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1
Padigi, Sudhaprasanna Kumar. "Multivalent Rechargeable Batteries." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2464.
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Li+ ion batteries have been the mainstay of high energy storage devices that have revolutionized the operating life time of consumer electronic devices for the past two decades. However, there is a steady increase in demand for energy storage devices with the ability to store more energy and deliver them at high power at low cost, without comprising safety and lifetime.
Li-ion batteries have had significant challenges in increasing the amount of stored energy without affecting the overall lifetime and the ability to deliver stored energy. In order to store and deliver more energy, more lithium ions need to be inserted and extracted from a given electrode (cathode or anode). Upon inserting a large number of Li ions, the crystal lattice of the materials undergo severe mechanical distortions, leading to un-desirable structural changes. This results in underutilization of theoretical energy storage capacities of the electrodes and early failure of the batteries owing to instabilities in the electrode materials.
Unlike monovalent Li+ ions, multivalent rechargeable batteries offer a potential solution to the above problems. Multivalent cations, such as Ca2+, are doubly-ionized as opposed to Li+ which is a monovalent cation. The advantages of using Ca2+ ions instead of Li+ ions are multifold. Due to the doubly-ionized nature, only half the number of Ca2+ ions need to be inserted and extracted from a given electrode to store and deliver energy from a high capacity cathode as compared to Li+ ions. This reduces the probability of lattice distortion and un-desirable structural changes, further leading to increased utilization of high theoretical energy storage capacities of the electrodes (cathode and anode). The use of Ca2+ ions also helps in delivering twice the amount of current density as compared to Li+ ions due to its doubly ionized nature.
In this work, a set of eight metal hexacyanoferrate compounds were synthesized using the following metal ions: Ba2+, Mn2+, Zn2+, Co2+, Fe3+, Al3+, Sn4+, Mo5+. The resulting metal hexacyanoferrate compounds were subjected to physical characterization using scanning electron microscope (SEM) and powder x-ray diffraction (XRD), to determine physical properties such as size, morphology, unit cell symmetry and unit cell parameters. This was followed by electrochemical characterization utilizing cyclic voltammetry and galvanic cycling, to determine the specific capacity and kinetics involved in the transport of Ca2+ ions to store charge. Optical characterization of the metal hexacyanoferrates using Fourier transform infrared (FTIR) spectroscopy, allowed for the identification of metal-nitrogen stretching frequency, which was used as a measure of the strength of the metal-nitrogen bond to understand the role of the above mentioned metal ions in electron density distribution across the unit cell of the metal hexacyanoferrates.
The specific capacity utilization of the metal hexacyanoferrates, when compared to the electronegativity values (Xi) of the above mentioned metal ions, the σ- parameter, and the metal-nitrogen stretching frequency (v), revealed an empirical trend suggesting that the materials (FeHCF, CaCoHCF and CaZnHCF) that possessed intermediates values for the above mentioned parameters demonstrated high capacity utilization (≥50%). Based on these empirical trends, it is hypothesized that a uniform distribution of electron density around a unit cell, as reflected by intermediate values of the electronegativity (Xi) of the above mentioned metal ions, the σ-parameter and the metal-nitrogen stretching frequency (v), results in minimal electrostatic interactions between the intercalating cation and the host unit cell lattice. This results in relatively easy diffusion of the cations, leading to high specific capacity utilization for metal hexacyanoferrate cathodes. These parameters may be used to select high efficiency cathode materials for multivalent batteries.
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Lu, Xueyi. "Architectural Nanomembranes as Cathode Materials for Li-O2 Batteries." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-228120.
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Li-O2 batteries have attracted world-wide research interest as an appealing candidate for future energy supplies because they possess the highest energy density of any battery technology. However, such system still face some challenges for the practical application. One of the key issues is exploring highly efficient cathode materials for Li-O2 batteries.
Here, a rolled-up technology associated with other physical or chemical methods are applied to prepare architectural nanomembranes for the cathode materials in Li-O2 batteries. The strain-release technology has recently proven to be an efficient approach on the micro/nanoscale to fabricate composite nanomembranes with controlled thickness, versatile chemical composition and stacking sequence.
This dissertation first focuses on the synthesis of trilayered Pd/MnOx/Pd nanomembranes. The incorporation of active Pd layers on both sides of the poor conductive MnOx layer commonly used in energy storage systems greatly enhances the conductivity and catalytic activity. Encouraged by this design, Pd nanoparticles functionalized MnOx-GeOy nanomembranes are also fabricated, which not only improve the conductivity but also facilitate the transport of Li+ and oxygen-containing species, thus greatly enhancing the performance of Li-O2 batteries. Similarly, Au and Pd arrays decorated MnOx nanomembranes act as bifunctional catalysts for both oxygen reduction reaction and oxygen evolution reaction in Li-O2 batteries. Moreover, by introducing hierarchical pores on the nanomembranes, the performance of Li-O2 batteries is further promoted by porous Pd/NiO nanomembranes. The macropores created by standard photolithography facilitate the rolling process and the nanopores in the nanomembranes induced by a novel template-free method supply fast channels for the reactants diffusion. In addition, a facile thermal treatment method is developed to fabricate Ag/NiO-Fe2O3/Ag hybrid nanomembranes as carbon-free cathode materials in Li-O2 batteries. A competing scheme between the intrinsic strain built in the oxide nanomembranes and an external driving force provided by the metal nanoparticles is introduced to tune the morphology of the 3D tubular architectures which greatly improve the performance by providing continuous tunnels for O2 and electrolyte diffusion and mitigating the side reactions produced by carbonaceous materials.
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Toigo, Christina Verena <1986>. "Towards eco-friendly batteries: concepts for lithium and sodium ion batteries." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10067/1/Thesis%20CT_final.pdf.
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Several possibilities are arising aiming the development of “greener”, more sustainable energy storage systems. One point is the completely water-based processing of battery electrodes, thus being able to renounce the use of toxic solvents in the preparation process. Despite its advantage of lower cost and eco-friendlyness, there is the need of similar mechanical and electrochemichal behavior for boosting this preparation mode.
Another point – accompanying the water-based processing - is the replacement of solvent-based polymer binders by water-based ones. These binders can be based on fluorinated, crude-oil based polymers on the one side, but also on naturally abundant and economic friendly biopolymers.
The most common anode materials, graphite and lithium titanate (LTO), have been subjected a water-based preparation route with different binder systems. LTO is a promising anode material for lithium ion batteries (LIBs), as it shows excellent safety characteristics, does not form a significant SEI and its volume change upon intercalation of lithium ions is negligible. Unfortunately, this material suffers from a rather low electric conductivity - that is why an intensive study on improved current collector surfaces for LTO electrodes was performed.
In order to go one step ahead towards sustainable energy storage, anode and cathode active materials for a sodium ion battery were synthesized. Anode active material resulted in a successful product which was then subjected to further electrochemical tests.
In this PhD work the development of “greener” energy storage possibilities is tested under several aspects. The ecological impact of raw materials and required battery components is examined in detail.
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Troncoso, Abelleira Maria Teresa. "Batteries for marine applications." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22408.
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The significant reduction in environmental emissions stated by the new IMO legislation, which specifies an amount of sulphur in fuels below 5% for 2020 and a NOx limit with an 80% reduction respect to the actual IMO limit within SECAS´s for 2016, aim the use of batteries as a propulsion source in hybrid marine power plants.Offshore vessels fit perfectly in the application of hybrid propulsion systems due to the large variations of energy requirements during their operation. Besides the reduction of emissions, the optimal combination between engines and batteries can be used for fast transients, smoothing the load of the engine and hence reducing the fuel consumption.The reasons behind the selection of the Lithium Ion battery as an ideal candidate for marine applications are stated in this thesis, through the comparison between the characteristics of different battery types.Simulation models of a Lithium Ion cell and a Lithium Ion battery pack at three complexity levels are developed in this thesis (simple, isothermal and thermal). Bond Graph approach is used for the model generation and 20Sim is used to perform the simulations.A safe operation window is stated for all levels since the performance of Lithium Ion cells is dependent on both, the temperature and the operating voltage. Therefore, both values must be kept within determined limits in order to avoid permanent damage in the cell.In case of the isothermal and thermal approaches, the electrochemical behaviour in the cell is considered and the main phenomena involved is represented, including: activation, conduction and diffusion, as well as, the dynamic effect of the electrochemical reactions and the heat release due to Joule heating.
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Rud, Andrew, and Андрій Андрійович Рудь. "Batteries of the spacecraft." Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/50736.
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1. Sineglazov V.M. Solar power plants based on rotary platforms - К: NAU, 2018.– 59 p. (in Ukrainian).
2. Ablesimov O.K., Alexandrov E.E., Alexandrova I.E. Automatic control of moving objects and technological processes. - Kharkiv: NTU "KhPI"The study and development of space requires the development and improvement of spacecraft for various purposes. In this case, it is economically feasible to increase the service life of the spacecraft. The high level of reliability and quality of operation of onboard systems and equipment of spacecraft largely depend on the efficiency of their power supply systems. As practice shows, the primary source of energy in the energy supply system is the solar battery. It determines the period of active existence of the spacecraft. Failure of the solar battery leads to the gradual failure of the entire power supply system.
Вивчення та освоєння космосу вимагає розробки та вдосконалення космічних кораблів різного призначення. У цьому випадку економічно доцільно збільшити термін служби космічного корабля. Високий рівень надійності та якості експлуатації бортових систем та обладнання космічних кораблів багато в чому залежать від ефективності їх систем електропостачання. Як показує практика, основним джерелом енергії в системі енергопостачання є сонячна батарея. Він визначає період активного існування космічного корабля. Несправність сонячної батареї призводить до поступового виходу з ладу всієї системи електропостачання.
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Fung, Kwok Yuk Anna. "A feasibility study of the used battery collection programme in Hong Kong /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21301876.
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Tam, Cheuk-wai. "A preliminary study of recycling batteries in Hong Kong /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17457075.
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Yang, Luyi. "Batteries beyond Li-ion : an investigation of Li-Air and Li-S batteries." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/384921/.
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Rohde, Michael [Verfasser], and Ingo [Akademischer Betreuer] Krossing. "New conducting salts for rechargeable lithium-ion batteries = Neue Leitsalze für wiederaufladbare Lithium-Ionen Batterien." Freiburg : Universität, 2014. http://d-nb.info/1123481490/34.
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Wang, Gang, Faxing Wang, Panpan Zhang, Jian Zhang, Tao Zhang, Klaus Müllen, and Xinliang Feng. "Polarity‐Switchable Symmetric Graphite Batteries with High Energy and High Power Densities." WILEY‐VCH, 2018. https://tud.qucosa.de/id/qucosa%3A34564.
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Multifunctional batteries with enhanced safety performance have received considerable attention for their applications at extreme conditions. However, few batteries can endure a mix‐up of battery polarity during charging, a common wrong operation of rechargeable batteries. Herein, a polarity‐switchable battery based on the switchable intercalation feature of graphite is demonstrated. The unique redox‐amphoteric intercalation behavior of graphite allows a reversible switching of graphite between anode and cathode, thus enabling polarity‐switchable symmetric graphite batteries. The large potential gap between anion and cation intercalation delivers a high midpoint device voltage (≈average voltage) of ≈4.5 V. Further, both the graphite anode and cathode are kinetically activated during the polarity switching. Consequently, polarity‐switchable symmetric graphite batteries exhibit a remarkable cycling stability (96% capacity retention after 500 cycles), a high power density of 8.66 kW kg−1, and a high energy density of 227 Wh kg−1 (calculated based on the total weight of active materials in both anode and cathode), which are superior to other symmetric batteries and recently reported dual‐graphite or dual‐carbon batteries. This work will inspire the development of new multifunctional energy‐storage devices based on novel materials and electrolyte systems.
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Valøen, Lars Ole. "Metal hydrides for rechargeable batteries." Doctoral thesis, Norwegian University of Science and Technology, Department of Materials Technology, 2000. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2068.
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Dumancic, Dominik. "Flow batteries : Status and potential." Thesis, Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-12975.
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New ideas and solutions are necessary to face challenges in the electricity industry. The application of electricity storage systems (ESS) can improve the quality and stability of the existing electricity network. ESS can be used for peak shaving, instead of installing new generation or transmission units, renewable energy time-shift and many other services. There are few ESS technologies existing today: mechanical, electrical and electrochemical storage systems. Flow batteries are electrochemical storage systems which use electrolyte that is stored in a tank separated from the battery cell. Electrochemistry is very important to understand how a flow battery functions and how it stores electric energy. The functioning of a flow battery is based on reduction and oxidation reactions in the cell. To estimate the voltage of a cell the Nernst equation is used. It tells how the half-cell potential changes depending on the change of concentration of a substance involved in an oxidation or reduction reaction. The first flow battery was invented in the 1880’s, but was forgotten for a long time. Further development was revived in the 1950’s and 1970’s. A flow battery consists of two parallel electrodes separated by an ion exchange membrane, forming two half-cells. The electro-active materials are stored externally in an electrolyte and are introduced into the device only during operation. The vanadium redox battery (VRB) is based on the four possible oxidation states of vanadium and has a standard potential of 1.23 V. Full ionic equations of the VRB include protons, sulfuric acid and the corresponding salts. The capital cost of a VRB is approximately 426 $/kW and 100 $/kWh. Other flow batteries are polysulfide-bromine, zinc bromine, vanadium-bromine, iron-chromium, zinc-cerium, uranium, neptunium and soluble lead-acid redox flow batteries. Flow batteries have long cycle life and quick response times, but are complicated in comparison with other batteries.Nya idéer och lösningar är nödvändiga för att möta utmaningarna i elbranschen. Användningen av elektriskt lagringssystem (ESS) kan förbättra kvalitén och stabiliteten av det nuvarande elnätet. ESS kan användas till toppbelastningsutjämning, istället för att installera nya produktions eller kraft överförnings enheter, förnybar energi tidsförskjutning och många andra tjänster. I dagsläget finns det få olika ESS: Mekaniska, elektriska och elektrokemiska lagringssystem. Flödesbatterier tillhör kategorin elektrokemiska lagringssystem som använder sig utav elektrolyt som är lagrad i en tank separerad från battericellen. För att kunna förstå hur flödesbatteriernas funktioner och på vilket sätt som dem lagrar elektriskt energi är det viktigt att kunna elektrokemi. Flödesbatteriernas funktion är baserad på reduktions och oxidations reaktioner i cellen. Nernsts ekvation används för att kunna uppskatta voltantalet i en cell. Nernsts ekvation säger hur halvcell potentialen ändras beroende av ändringen av koncentrationen av ämnet involverat i oxidations eller reduktions reaktionen. Det första flödesbatteriet uppfanns 1880-talet, men blev bortglömt under en lång tid. Vidare utveckling förnyades under 1950 och 1970-talet. Ett flödesbatteri består utav två parallella elektroder som är separerade utav ett jonbytes membran vilket formar två halvceller. Dem elektroaktiva materialen är lagrade externt i elektrolyt och är införs bara i anordningen under användning. Vanadium redox batteriet (VRB) är baserat på dem fyra möjliga oxidations tillstånden av vanadium och har en standard potential på 1.23 V. Fullt joniska ekvationer av VRB inkluderar protoner, svavelsyra och deras motsvarande salter. Kapitalkostnaden av ett VRB är ungefär 426 $/kW och 100 $/kWh. Det finna andra flödesbatterier som är polysulfide-brom, zink-brom, vanadium-brom, järn-krom, uran, neptunium och löslig blysyre redox flödesbatterier. Flödesbatterier har en lång omloppstid samt en snabb svarstid men är komplicerade jämfört med andra batterier.
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Paul, Gary William. "Absenteeism management at Willard Batteries." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/896.
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The main research problem in this study centred around the assessment of the impact of an absenteeism monitoring and management system at Willard Batteries. The main research problem had five sub-problems which were addressed through the following actions: A literature study was conducted to identify the causes and impact of absenteeism in the workplace. The researcher also conducted interviews with the Human Resources Manager, line managers and employees at Willard Batteries to obtain their views of the absenteeism management strategies utilised, as well as the effects of absenteeism in their organisation. The insights gained from these interviews were incorporated into the questionnaire. The absenteeism figures of the organisation for the period 2005 to 2008 were analysed and compared against the internationally accepted absenteeism norm of three percent. An absence rate above three percent is considered as unacceptable and would imply that the current absenteeism management system is not effective. The theoretical study also entailed the reviewing of the legal framework within which absenteeism needs to be managed, as well as the literature that deals with strategies for the effective management of absenteeism. These strategies relate to the recording, calculation, analysis, benchmarking and practical management of absenteeism in the workplace. A survey questionnaire was developed to determine the perceptions of managers, supervisors and employees in relation to the impact of absenteeism on the company as well as the extent to which managers and supervisors were utilising selected absenteeism monitoring and management strategies within the company. The results from the empirical study revealed that management and supervisors were more aware of the impact of absenteeism on the organisation than their employees. It can therefore be concluded that employees perceived their absence from work to have little impact on aspects such as employee morale, cost, production and the customer. This could possibly be due to ineffective communication in terms of the cost and other consequences of absenteeism in the organisation. Employees also felt that managers were effective in taking the necessary disciplinary action with regards to absenteeism-related transgressions, but that they were not diligent in the recording and communication of absence information, as well as comparing absenteeism information inter-departmentally. Absenteeism has proven to be globally pervasive, expensive and extremely disruptive to organisations. Managers and supervisors who employ the various absence monitoring and management strategies, could be more effective in improving employee attendance. Their efforts could be further enhanced if employees are made aware of the negative impact that their absence has on the morale of their fellow employees, the cost to the company, the customer, as well as the achievement of production targets and the quality of outputs.
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Herstedt, Marie. "Towards Safer Lithium-Ion Batteries." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3542.
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Lagerbäck, Findus. "Charging Switch for two batteries." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93588.
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Uppgiften är att utveckla och tillverka en prototyp till en laddningsomkopplare för 12 V. Att parallellkoppla blybatterier med olika kapacitet eller kondition kan medföra problem. Därför ska en omkopplare byggas, som kopplar om laddströmmen från regulatorn till två batterier så att de kan laddas automatiskt utan att behöva parallellkopplas. Den kopplar ihop laddningsregulatorn med det batteri som ska hållas fulladdat (hädanefter kallat primärbatteriet), så länge detta inte uppnått full spänning. När det är fulladdat kopplar omkopplaren laddningsregulatorn till det andra batteriet (hädanefter kallat sekundärbatteriet). Om primärbatteriets spänning sjunker, p.g.a. energiuttag, kopplar omkopplaren tillbaka laddningsregulatorn till det, så att det hålls fulladdat. Laddningsomkopplarens omkopplingsspänning kan ställas in med en potentiometer och spänningsskillnaden mellan till- och frånslag med en annan. Laddningsomkopplaren är avsedd att användas tillsammans med solceller, men kan även användas med andra strömkällor. Liknande anordningar för specifika laddningsregulatorer finns redan på marknaden, men den laddningsomkopplare som utvecklas i detta examensarbete kan kopplas till godtycklig laddningsregulator för 12V-blybatterier.
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Hopkins, Brandon J. (Brandon James). "Mechanical design of flow batteries." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/87922.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 72-73).
The purpose of this research is to investigate the design of low-cost, high-efficiency flow batteries. Researchers are searching for next-generation battery materials, and this thesis presents a systems analysis encompassing static and moving electrode architectures that identifies which architecture is most appropriate for which materials and how to modify those materials to decrease cost and increase efficiency. The cost model and mechanical designs presented will help researchers (i) identify how to modify existing materials, (ii) find new desirable materials, and (iii) use those materials in novel flow battery structures to create next-generation batteries.
by Brandon J. Hopkins.
S.M.
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Tangirala, Ravichandra. "Developments in redox flow batteries." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/361961/.
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This thesis describes the investigation of the electrochemistry principles, technology, construction and composition of the electrode materials, electrolyte and additives used in redox flow batteries. The aim was to study a flow battery system with an appreciable working performance. The study explores and compares mainly three different redox flow battery technologies; all-vanadium, soluble lead-acid and a novel copper-lead dioxide flow batteries. The first system is based in sulfuric acid electrolyte environment whilst the other two are in methanesulfonic acid. Various cell parameters such as cell voltage, individual electrode potentials, flow rate and efficiencies (in particular voltage, charge and energy) have been utilized to compare. Further research in other redox couples and comparative study towards the design, construction and electrochemistry, along with the performance of these three batteries in relation to other electrochemical energy storage technologies available was also discussed. These technological studies are of particular interest for applications in the renewable energy storage (offshore and onshore) and sustainable energy research (grid integration and micro generation).
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Xu, Chao. "All silicon lithium-ion batteries." Licentiate thesis, Uppsala universitet, Strukturkemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-261626.
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Lithium-ion batteries have been widely used as power supplies for portable electronic devices due to their higher gravimetric and volumetric energy densities compared to other electrochemical energy storage technologies, such as lead-acid, Ni-Cd and Ni-MH batteries. Developing a novel battery chemistry, ‘‘all silicon lithium-ion batteries’’, using lithium iron silicate as the cathode and silicon as the anode, is the primary aim of this Ph.D project. This licentiate thesis is focused on improving the performance of the silicon anode via optimization of electrolyte composition and electrode formulation. Fluoroethylene carbonate (FEC) was investigated as an electrolyte additive for silicon composite electrodes, and both the capacity retention as well as coulombic efficiency were significantly improved by introducing 10 wt% FEC into the LP40 electrolyte. This is due to the formation of a stable SEI, which mainly consisted of FEC decomposition products of LiF, -CHFOCO2-, etc. The chemical composition of the SEI was identified by synchrotron radiation based photoelectron spectroscopy. This conformal SEI prevented formation of large amounts of cracks and continues electrolyte decomposition on the silicon electrode. An alternative lithium salt, lithium 4,5-dicyano-2-trifluoromethanoimidazole (LiTDI), was studied with the silicon electrode in this thesis. The SEI formation led to a rather low 1st cycle coulombic efficiency of 44.4%, and the SEI layer was found to contain hydrocarbon, ether-type and carbonate-type species. Different to conventional composite silicon electrodes, which require heavy and expensive copper current collector, a flexible silicon electrode, consisted of only silicon nanopowder, Cladophora nanocellulose and carbon nanotube, was facilely prepared via vacuum filtration. The electrode showed good mechanical, long-term cycling as well as rate capability performance.
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FACCHINETTI, IRENE. "Thermally Regenerable Redox-Flow Batteries." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/308694.
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Il calore a bassa temperatura (LTH), inferiore a 100°C, è una forma di energia largamente disponibile che viene dispersa nell’ambiente, senza alcun utilizzo. La conversione di questo tipo di energia in elettricità aprirebbe le porte allo sfruttamento di fonti energetiche come il calore solare, geotermico e di scarto industriale.
La conversione di LTH in elettricità non è però un processo efficiente a causa dei limiti posti dalla termodinamica, con la cosiddetta legge di Carnot, oltre che ai limiti tecnologici che riducono ulteriormente la conversione di questa forma di energia.
I dispositivi preposti per convertire LTH in elettricità devono poter operare con alte efficienze e potenze, e devono essere facilmente scalabili ed economici. Purtroppo, attualmente nessun dispositivo è in grado di effettuare questa conversione con potenze ed efficienze abbastanza elevate da giustificare gli alti costi (materiali, operazionali e manutenzione) e la complessità dei dispositivi stessi ed è per questo motivo che LTH non trova tutt’ora alcuna applicazione
Questo progetto di ricerca si è focalizzato sullo sviluppo di un dispositivo in grado di convertire LTH in maniera efficiente e con alte potenze. Tale dispositivo, chiamato Thermally Regnerable Redox-Flow Battery, TRB, è una batteria a flusso ricaricabile termicamente. Il dispositivo conta due diverse processi: la produzione energetica, che avviene in una cella elettrochimica in grado di produrre elettricità alle spese dell’energia libera di mescolamento di due soluzioni acquose dello stesso sale ma a diversa concentrazione. Quando le due soluzioni raggiungono la stessa concentrazione, la soluzione esausta viene mandata al secondo processo: un distillatore sottovuoto che rigenera il gradiente di concentrazione tra le due soluzioni sfruttando risorse di LTH. L’efficienza totale del dispositivo è quindi data dal prodotto tra l’efficienza della cella elettrochimica e l’efficienza del distillatore.
Studi termodinamici dimostrano che per incrementare tale efficienza è fondamentale lavorare sull’efficienza del distillatore, il cui valore dipende dalla scelta del soluto e del solvente. In particolare, per questo lavoro di ricerca si è scelto di operare con soluzioni acquose di NaI/I2 e LiBr/Br2.
I risultati raggiunti e le principali attività di ricerca vengono riportate brevemente in questo abstract:
Con la determinazione dei coefficienti di attività, si è calcolato l’energia libera di mescolamento e il potenziale a circuito aperto per entrambi i set di soluzioni (NaI e LiBr).
Le celle elettrochimiche sono state sviluppate specificamente per entrambi I sistemi studiati e test elettrochimici hanno permesso di valutare le performance dei due dispositivi, come potenza ed efficienza elettrochimica. La distillazione è stata modellizzata in modo da definire le condizioni ottimali di lavoro e determinare l’efficienza del processo.Low-Temperature Heat (LTH), below of 100°C, has elicited great interest among the scientific community, as a source of energy since it does not see any form of utilization as it is currently simply released into the environment. Its conversion would open the doors to the exploitation of a huge amount of energy as well, such as geothermal, solar, and industrial waste heat. The conversion efficiencies of LTH are low because of the limitations imposed by Carnot law, as well as the existence of technological limits which further reduce the efficiency of the conversion of LTH. In order to be suitable for extensive industrial production, LTH converters should show high power densities, scalable and efficient whilst being cost-effective; to this point, the devices proposed for this afore mentioned application all failed to achieve suitable efficiencies and power density, making the LTH conversion unfeasible. This PhD project was focused on the design of a device called Thermally Regenerable Redox-Flow Battery (TRB) consisting of a redox-flow battery that can be recharged by a thermal process. The device is based upon a two-stages technology composed by a “power production” stage and a “thermal” stage: power production happens in an electrochemical cell which release electricity at the expenses of the mixing free energy of two water solutions of the same salt at different concentrations, referred to as a concentration cell. When the two solutions reach the same concentration, the exhausted fluid is sent to the second stage, the thermal process, which regenerates the initial mixing free energy, by exploiting LTH sources, through vacuum distillation. The efficiency of the technology is the product between the efficiencies of the units in the device where both stages happen: the electrochemical cell, engineered for power production, and a distillation unit, designed to be responsible for thermal conversion. NaI/I2 and LiBr/Br2 water solutions will be the most discussed redox couple in this thesis, as result of thermodynamic analysis that have shown the importance related to the solvent and salt choice to ensure high energy conversion efficiencies. The achieved results, as well as the main research activities, are briefly reported here: starting from the determination of the activity coefficients, mixing free energy of the initial solutions, and the open circuit voltage of the electrochemical are calculated. Electrochemical cells are specifically designed for both systems while electrochemical tests are performed to evaluate the main performances of the devices, such as power density and electrochemical efficiency. Modeling of the operational conditions of the thermal stage allows to determine the distillation efficiency for both the solutions. The initial experiments prove an unprecedented heat-to-electricity efficiency for both the systems: 3% for TRB-NaI and 4-5% for TRB based on LiBr, depending on the thickness of the membrane with a power density output of almost 10 W m-2 for both technologies, which opens various possibilities to implement further improvements into this new class of energy storage/converter devices.
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Jouhara, Alia. "De la conception de matériaux d'électrode organiques innovants à leur intégration en batteries "tout organique"." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4026/document.
Full textAbstract:
Répondre aux besoins croissants en termes de stockage électrochimique sans épuiser les ressources naturelles exige de promouvoir des technologies de batteries en rupture à la fois efficientes mais aussi à faible impact au plan environnemental. La conception de batteries organiques pourrait s'avérer être une partie de la solution. En effet, la richesse de la chimie organique offre une multitude de possibilités pour développer des matériaux d'électrode innovants à partir d’éléments abondants et peu coûteux. Près de 40 ans après la découverte des polymères conducteurs, des batteries Li-organiques offrent maintenant d’intéressantes performances en cyclage. Pourtant, la synthèse de matériaux organiques lithiés électroactifs à haut-potentiel ainsi que celle de matériaux organiques de type p électroactifs à bas potentiel se sont avérées assez complexes et par conséquent, très peu d'exemples de cellules « tout organique » existent. Au cours de ce travail de recherche, nous avons mis en lumière une approche chimique originale consistant à perturber la structure électronique de l’entité organique électroactive (modulation des effets inductifs) au moyen d’un cation spectateur faiblement électropositif ce qui conduit à une augmentation significative du potentiel redox des matériaux d'électrodes organiques lithiés déjà connus. Cette découverte nous a permis de développer une batterie Li-ion « tout organique » capable d’offrir une tension de sortie d’au moins 2,5 V sur plus de 300 cycles. Ensuite, nous avons cherché à concevoir des matériaux de type p capables de fonctionner à bas potentiel et ainsi élaboré des batteries Anion-ion « tout organique ». Enfin, une étude préliminaire d’une nouvelle famille de composés potentiellement bipolaires au plan redox (intégration de centres redox de type n et de type p) a également été réaliséeMeeting the ever-growing demand for electrical storage devices, without depleting natural resources, requires both superior and “greener” battery technologies. Developing organic batteries could well provide part of the solution since the richness of organic chemistry affords us a multitude of avenues for uncovering innovative electrode materials based on abundant, low-cost chemical elements. Nearly 40 years after the discovery of conductive polymers, long cycling stability in Li-organic batteries has now been achieved. However, the synthesis of high-voltage lithiated organic cathode materials and the synthesis of low-voltage p type organic anode materials is still rather challenging, so very few examples of all-organic cells currently exist. Herein, we first present an innovative approach consisting in the substitution of spectator cations and leading to a significant increase of the redox potential of lithiated organic electrode materials thanks to an inductive effect. These results enable developing an all-organic Li-ion battery able to deliver an output voltage above 2.5 V for more than 300 cycles. We then design two p type organic electrode materials able of being charged at low potentials for developing all-organic Anion-ion batteries able to deliver an output voltage at least 1.5 V. Finally, we present a preliminary study of a new family of potentially bipolar compounds
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Leandersson, Regina. "Optimal usage of EV batteries – V2X and second life of batteries : From a circular economy perspective." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281779.
Full textAbstract:
The increased number of electric vehicles (EV) will influence the electricity demand and could possibly exceed the maximum power available on the grid. In order to manage such development, new innovations and impactful policy mechanisms are crucial. EV fleets are prospected to work as dynamic energy storage systems and if controlled smartly, it could result in energy savings and revenue streams. The EV could, be charged when electricity prices are low and discharged when high. Thus, discharged power could be sold to the grid or supplied to a building. This could then generate revenue streams and enhance self-consumption through services called vehicle-to-grid (V2G) and vehicle-to-building (V2B). Despite the advantages of V2X (vehicle-to-anything), premature battery degradation due to capacity loss as a consequence of charging and discharging processes is a prominent concern since the battery is unfit for EV when it reaches 80 percent of the initial capacity. This could be managed by providing the battery a second life as storage solution and thus enhance the feasibility, and lifetime for EV batteries thereby contributing to circular economy. Previous studies have investigated the possibility of EV as energy vectors and optimizing the charging and discharging schedules for demand supply management, for example in peak shredding or shifting. This study aims to combine the mechanism of V2B and V2G and further providing the EV battery a second life in residential PV storage to optimize the usage through the battery’s lifetime in a circular perspective. Hence, for this thesis, a mixed integer linear problem (MILP) was developed to optimize the potential, savings and earnings from V2B/V2G as well as from second-life energy storage in residential PV. For this purpose, a case study with real data from a residential building with a build-in PV from 2018 in Switzerland was integrated. Further, the impact of the batteries in the two stages and the contribution towards a circular economy was investigated. Results show that the battery lifetime from exercising V2G/V2B could at its worst last for 3.11 years. This is however strongly impacted from input data, degradation and selling price of electricity. During its lifetime, the EV battery could avoid 26% of cost compared with not using V2X. Overall, V2B/V2G leads to energy and economic savings, but there is degradation in the battery and the savings made by V2B/V2G is not enough to justify the investment costs of an EV battery. Hence, the cost of replacing the battery in the EV due to the degradation of V2B/V2G needs to be subsidized or by other incentives for it to become feasible. When further providing the battery a second life, it shows huge potential in savings as observed from the result which contributes to resource efficiency and circular economy. In this study, the reused battery could last for either 2.4 or 9.45 years, depending on the electricity selling price. Thus, the lifetime usage of the battery can be increased substantially with second life of batteries depending on the application.Det ökande antalet elbilar kommer att resultera i ökad efterfrågan av elektricitet och då även överskrida tillgängligheten på elnätet. För att hantera utveckling som denna är nya innovationer och kraftfulla policys vitalt. Elbilar förväntas att kunna användas som dynamisk energilagring och leda till energibesparingar och intäkter. Genom innovationer som vehicle-to-grid (V2G) och vehicle-to-building (V2B) finns det potential för elbilar att ladda upp batteriet när elpriserna är låga och sedan ladda ur batteriet när priserna är höga. Den urladdade energin kan då exempelvis säljas till elnätet (V2G) eller levereras till en byggnad (V2B) och således leda till intäkter eller reducerade elkostnader. Trots fördelarna med att tillämpa elbilsbatterier för urladdning, tillkommer följder av ökad degradering av batteriet på grund av upp- och urladdning. Då batteriet inte är lämpligt för användning i elbilar när det degraderat till 80 procent av den initiala kapaciteten, finns det även en problematik. Detta skulle kunna hanteras genom att återanvända batteriet i lagringslösningar och öka lönsamheten i att använda dynamisk energilagring, förlänga livslängden men även bidra till den cirkulära ekonomin. Den här studien syftar till att optimera potentialen, besparingar och intäkter av elbilsbatterier i ett cirkulärt perspektiv genom V2B och V2G och därefter återanvända elbilsbatteriet för energilagring med solceller i ett bostadshus. För detta, användes linjär programmering. Vidare integrerades en fallstudie med verkliga data från ett bostadshus i Schweiz med solceller. Resultaten visar att batteriets livslängd reduceras till 3,11 år genom att använda V2G/V2B, men är starkt påverkat av inmatningsdata, degraderings modellen och försäljningspriset av elektricitet. Under batteriets livstid kunde elbilsbatteriet undvika 26% av elkostnaderna jämfört med att inte implementera V2B/V2G. Sammantaget leder sådan användning av elbilsbatterier till energi- och ekonomiska besparingar, men på grund av den signifikanta reduceringen i livslängd och höga investeringskostnader, räcker det inte för att motivera implementerandet av sådana tekniker som det ser ut idag. Det finns därmed ett behov av subventionering av elbilsbatterier för att använda V2B/V2G. Vidare, när batteriet återanvänds, visar resultaten signifikant besparingspotential som kan bidra till resurseffektivitet och cirkulär ekonomi. I den här studien, varierar livslängden på det återanvända batteriet mellan 2,4 och 9,45 år som ett resultat av försäljningspriset av elektricitet. Således kan batteriets livslängd beroende på applikation förlängas avsevärt genom återanvändning.
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Purushothaman, Bushan K. "DEVELOPMENT OF BATTERIES FOR IMPLANTABLE APPLICATIONS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1151609663.
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Poli, Federico. "Design of novel redox flow batteries." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Find full textAbstract:
Questo lavoro di tesi partendo da un'analisi bibliografica delle tecnologie di batterie più avanzate allo stato solido e a flusso, sottolinea le potenzialità delle batterie metallo aria in particolare Li/O2 per applicazioni stazionarie e per il veicolo elettrico.
L'ottimizzazione delle prestazioni delle batterie a flusso richiede un'accurata ingegnerizzazione del disegno di cella e studi di fluidodinamica per la valutazione dell'impatto dei flussi sul funzionamento della batteria. Le cadute di pressione attraverso la cella generano, infatti, una perdita di potenza che deve essere minimizzata mediante opportune geometrie di cella.
Lo scopo di questa tesi è la modellizzazione e la valutazione sperimentale delle cadute di pressione attraverso prototipi di laboratorio di celle Li/O2
L’analisi dei disegni di celle a flusso proposte in letteratura ha permesso di realizzare un primo prototipo ottenuto con stampa 3D cha ha evidenziato come un intelligente geometria di cella permetta di ridurre drasticamente le cadute di pressione anche con sistemi viscosi quali gli elettroliti organici utilizzati nelle batterie a più alta energia specifica.
L'integrazione tra simulazioni numeriche e prove elettrochimiche su celle Li/O2 reali ha permesso di proporre il disegno di un terzo prototipo di cella sempre con l'obbiettivo di massimizzare la potenza netta della cella.
Da sottolineare che l'accuratezza della descrizione fluidodinamica nei prototipi virtuali studiati ha avuto conferma dalle misure sperimentali effettuate.
Questa tesi pertanto contribuisce a dimostrare come gli approcci numerici utilizzati siano metodi estremamente potenti per accelerare l'attività di prototipazione di batterie redox a flusso avanzate, in particolare metallo aria, e per portare tali tecnologie a raggiungere valori di energie e potenze specifiche superiori rispetto allo stato dell'arte.
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Andersson, Anna. "Surface Phenomena in Li-Ion Batteries." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5120-9/.
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Kawai, Hiroo. "Cathode materials for 5V lithium batteries." Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287603.
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Complex spinel-structure oxides based on Li2MM'3O8 and LiMM'O4 have been systematically investigated on the basis of solid state chemistry and thermodynamics, and are found to constitute a novel family of cathode materials for 5 V lithium batteries. We have targeted lithium cathode materials that operate over 5 V, linked to large capacity and good cycling stability. The spinels prepared by solid state synthesis have been characterised using powder X-ray and neutron diffraction, impedance measurements, thermal analyses, magnetic measurements, XANES spectroscopy, Mossbauer spectroscopy and electrochemical measurements. In a single lithium cell, Li2CoMn3O8 and LiCoMnO4 are shown to be the first cathode materials to operate at discharge voltages over 5 V; Li2FeMn3O8 operates at a discharge plateau commencing at 5 V and centred on 4.9 V, offering potentially great economic and environmental advantages as a lithium cathode. LiCoMnO4 exhibits a discharge capacity of ca. 95 mAhg-1 at a long plateau centred on 5.0 V in a cell, Li/LiPF6, propylene carbonate / LiCoMnO4, and therefore has superior energy density to LiMn2O4, the cathode material used in state-of-the-art cells. This renders LiCoMnO4 potentially very attractive as a cathode material in practical 5 V lithium battery systems.
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Al-Mahmoud, Saddam Mohammad. "Lithium/sulphur batteries : an electrochemical study." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/382901/.
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The lithium/sulfur battery has been investigated as an attractive candidate for the rechargeable energy storage system, since it can potentially deliver a much higher energy than a typical lithium ion battery of the same weight. In this work, sulfur/acetylene black composite electrodes were prepared by the ball milling method and studied cells with various electrolyte systems. A significant impact of the electrolyte viscosity on the electrochemical performance of the cells was explained in terms of the electrolyte penetration into the sulfur electrode structure, the diffusion rate of lithium salts and the dissolution rate of the solid active materials. Sulfur/acetylene black (AB) composites were also prepared using a direct precipitation method. The smaller particles of sulfur, as well as the well-distributed AB on the surface of sulfur particles resulting from the precipitation method was found to provide a more uniform and conductive S/AB composite with a larger surface area. The resulting electrodes showed less degradation on cycling than those prepared by milling method.A simple quantitative one-dimensional model of the initial self-discharge has been developed in terms of diffusion of a polysulfide shuttle species. Despite the simplicity of the model, it reproduces very well the decrease in the open circuit potential of the cells under a range of experimental conditions (varying the number of separators between the electrodes, the amount of AB in the sulfur electrode and the pre-saturation of the electrolyte with sulfur). The model provides a detailed understanding of the mechanism of self-discharge, quantifying the two main causes of sulfur loss from the positive electrode: dissolution followed by diffusion down a concentration gradient and direct reaction with polysulfides arriving from the lithium electrode.
Galvanostatic Intermittent Transient Technique (GITT) measurements were conducted to study the diffusion behaviour in Li/S cells. Analysis of the transient voltage change during and after current pulses was performed at different states of discharge/charge. The relaxation time was optimised to avoid errors due to poor equilibration at short times and self-discharge during longer periods.
Finally, the effect of the shuttle reaction on the electrochemical performance of Li/S cells was investigated using a lithium ion conducting glass ceramic (LICGC) separator in an effort to eliminate the self-discharge. This resulted in a higher discharge capacity and more accurate GITT results, showing that better controlled diffusion conditions can be achieved in a Li/S cell containing LICGC separator.
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Harrison, Harry. "Practical magnetic tomography for lead batteries." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/21428/.
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A variety of economic factors currently motivate the development of electrochemical energy storage. The effective use of renewable energy requires short term storage, for which electrochemical cells may be used. Electrified transport is also driving development; stored energy limits the range of electric vehicles. In hybrid vehicles, improved dynamic charge acceptance will help to optimise powertrain efficiency. A non-invasive measurement of current distribution within a cell is a useful aid to understanding its operation and optimising its design. Here, the coupling between the cell current and the resulting magnetic field is exploited by taking measurements of magnetic flux density outside the cell and inferring the current distribution within. This technique may be termed magnetic tomography or magnetotomography. In this thesis, a practical system is implemented in order to observe the current distribution within a single lead acid cell. An existing method of constraining and solving the inverse problem is adapted for use in conjunction with 3D finite element software, to make it suitable for modelling the complex geometry of a commercial electrode. Some tolerance of unknown material conductance is built into the solver method. An array of sensors is used to obtain a set of magnetic field measurements simultaneously, allowing temporally- and spatially- resolved current distribution images. Solutions from the magnetic tomography system are verified against data from an array of ferrous cores, submerged in the electrolyte. Measurements are taken while the cell is operated at a current of approximately 0.625 C. The current distribution is found to be very uniform throughout most of the testing, although fatigue of the cell plates does lead to a non- uniform distribution. The magnetic tomography system is tested on both uniform and non- uniform distributions. Mean absolute errors of approximately 5 – 7 % are achieved. The effect of model errors on solution accuracy is investigated.
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Burch, Damian. "Intercalation dynamics in lithium-ion batteries." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54233.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 153-160).
A new continuum model has been proposed by Singh, Ceder, and Bazant for the ion intercalation dynamics in a single crystal of rechargeable-battery electrode materials. It is based on the Cahn-Hilliard equation coupled to reaction rate laws as boundary conditions to handle the transfer of ions between the crystal and the electrolyte. In this thesis, I carefully derive a second set of boundary conditions--necessary to close the original PDE system--via a variational analysis of the free energy functional; I include a thermodynamically-consistent treatment of the reaction rates; I develop a semi-discrete finite volume method for numerical simulations; and I include a careful asymptotic treatment of the dynamical regimes found in different limits of the governing equations. Further, I will present several new findings relevant to batteries: Defect Interactions: When applied to strongly phase-separating, highly anisotropic materials such as LiFePO4, this model predicts phase-transformation waves between the lithiated and unlithiated portions of a crystal. This work extends the analysis of the wave dynamics, and describes a new mechanism for current capacity fade through the interactions of these waves with defects in the particle. Size-Dependent Spinodal and Miscibility Gaps: This work demonstrates that the model is powerful enough to predict that the spinodal and miscibility gaps shrink as the particle size decreases. It is also shown that boundary reactions are another general mechanism for the suppression of phase separation.
(cont.) Multi-Particle Interactions: This work presents the results of parallel simulations of several nearby crystals linked together via common parameters in the boundary conditions. The results demonstrate the so-called "mosaic effect": the particles tend to fill one at a time, so much so that the particle being filled actually draws lithium out of the other ones. Moreover, it is shown that the smaller particles tend to phase separate first, a phenomenon seen in experiments but difficult to explain with any other theoretical model.
by Damian Burch.
Ph.D.
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Chang, Michael Tse-Gene. "Performance targets for electric vehicle batteries." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97943.
Full textAbstract:
Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, Engineering Systems Division, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 79-88).
Light-duty vehicle transportation accounted for 17.2% of US greenhouse gas emissions in 2012 [95]. An important strategy for reducing CO₂ emissions emitted by light-duty vehicles is to reduce per-mile CO₂ emissions. While one approach is to improve vehicle efficiency, greater reductions in emissions can be achieved by switching from gasoline vehicles to electric vehicles, if the electric vehicles run on electricity from clean energy sources. Batteries affect the consumer adoption of electric vehicles by influencing two important vehicle characteristics: cost and driving range on a single charge. The cost of the battery is a significant fraction of total vehicle cost, and the battery's energy capacity determines driving range. To lower battery costs and improve battery energy capacity, further research is needed. To guide such research, several organizations have created performance targets for batteries, including the Advanced Research Projects Agency-Energy (ARPA-E) and the US Advanced Battery Consortium (USABC). The goal of this thesis is to assess these performance targets based on real-world vehicle performance. A method is developed for estimating the energy requirements of personal vehicle travel, which improves upon previous methods by accounting for per-trip variation of vehicle energy consumption and analyzing data with wider geographic scope. The method consists of a model of battery-to-wheel vehicle energy consumption and a conditional bootstrap procedure for combining GPS travel data with large-scale data from the US National Household Travel Survey. The research finds that the distribution of energy requirements for US vehicle-trips and vehicle-days (the sum of all trips taken in a day) has a heavy tail, namely that a small proportion of long trips accounts for a disproportionately large amount of energy consumption. Current electric vehicle batteries (2011 Nissan Leaf) can satisfy 83% of vehicle-days, which account for 53% of all energy consumed in personal vehicle travel, while batteries that meet the performance targets can satisfy 98 to 99% of vehicle-days, which account for 90 to 96% of energy. These results allow for a quantification of the benefits of meeting performance targets for battery energy capacity, which can help assess technology readiness and guide allocation of research funding.
by Michael Tse-Gene Chang.
S.M. in Technology and Policy
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Olivetti, Elsa A. "Composite cathodes for lithium rechargeable batteries." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39554.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.Includes bibliographical references.
The utility of incorporating continuous, nanoscale vanadium oxide phases within preferred domains of self-organizing copolymers was investigated towards the fabrication of composite, nanoarchitectured electrode materials for solid-state rechargeable batteries. In situ growth of cathodic phases within ion-conducting copolymer domains was explored as a means to control morphology and to increase the surface-area-to-volume ratio, thereby increasing the specific electrode area for faradaic reactions and decreasing ion diffusion distances within the electrode-active material. Copolymers of microphase-separating rubbery block and graft copolymers, previously developed as solid electrolytes, provide a matrix for directing the synthesis of an inorganic battery-active phase. The copolymers include poly[(oxyethylene)9 methacrylate]-block-poly(butyl methacrylate) (POEM-b-PBMA) with a domain periodicity of -35 nm made by atom transfer radical polymerization, and poly[(oxyethylene)9 methacrylate]-graft-poly(dimethyl siloxane) (POEM-g-PDMS) with a domain periodicity of-17 nm made by free radical polymerization. The resulting microphase-separated polymer is a structure of alternating hydrophilic (Li-ion conducting) and hydrophobic regions.
(cont.) Sol-gel chemistry involving a vanadium alkoxide precursor enabled the in situ growth of cathode-active vanadium oxide within the continuous ion-conducting POEM domains of the microphase-separated copolymers. Resulting films, termed POEM-b-PBMA/VOx and POEM-g-PDMS/VOx, were freestanding and mechanically flexible. Small angle x-ray scattering and transmission electron microscopy revealed the nanoscale morphology of the composite and confirmed the spatially-selective incorporation of up to 34 wt% VO, in POEM-b-PBMA and 31 wt% in POEM-g-PDMS. Electronically conductive components, necessary for wiring of the lithium-active vanadium oxide domains to the external circuit, were added through a variety of methods. Dispersions of acid-treated and cryo-ground carbon black within POEM-b-PBMA/VOx enabled the cycling of this material as a cathode. Reversible capacities of-~ 40 mAh/g were measured for batteries fitted with a polymer electrolyte doped with LiCF3SO3 and a lithium foil anode. Electrolyte thickness studies indicated battery performance was limited by the ionic conductivity of the solid electrolyte.
(cont.) Using liquid electrolyte resulted in improved capacity (at higher currents) over conventional composite cathodes made from sol-gel derived vanadium oxide without the polymer matrix. The vanadium oxide nanoarchitecture was preserved upon removal of the polymer by heat treatment. The resulting templated vanadium oxide, when repotted with carbon black and binder, exhibited improved capacity at high current over non-templated vanadium oxide cathodes.
by Elsa A. Olivetti.
Ph.D.
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Ariel, Nava. "Integrated thin film batteries on silicon." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33612.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.Includes bibliographical references (p. 147-158).
Monolithic integration has been implemented successfully in complementary metal oxide semiconductor (CMOS) technology and led to improved device performance, increased reliability, and overall cost reduction. The next element to be incorporated on the silicon chip is the power unit; possibly as part of the back end process of the very large scale integrated (VLSI) circuits' production. This thesis describes the work done in developing and studying thin film integrated lithium ion batteries compatible with microelectronics with respect to the material system employed, the cells' fabrication methods, and performance. The project consisted of three stages; first, a material system new to the battery application field was explored and power cells were fabricated and characterized. In the second stage, the fabrication process of the first material system cells was optimized thereby improving their performance. The third stage dealt with a more conventional battery material system, utilizing thin film technology to fabricate and explore power cells.
(cont.) All the cells fabricated in this work were created using microelectronic technology and were characterized by thin film analysis techniques and by measurement equipment commonly used for microelectronic device testing. The cells were fabricated in four sizes of active areas: 5x5 mm², 2x2 mm², lxl mm², and 0.5x0.5 mm². The first material system consisted of a novel lithium-free electrolyte in the form of an ultra-thin SiO₂ layer, thermally grown from sacrificial polysilicon layer on a doped polysilicon anode. The concept of SiO₂ as an electrolyte is innovative since common solid state lithium and lithium ion batteries consist of 1-2 ptm thick lithium-containing electrolytes. The controlled transport of lithium through SiO₂, 9-40 nm thick, was studied for electrolyte application. The fabricated LiCoO₂/SiO₂/polysilicon cells were successfully charged and discharged. This stage of the project demonstrated the concept of an ultra-thin lithium free electrolyte layer and introduces SiO₂ as an interesting candidate material. The second stage of the project focused on improving the LiCoO₂/SiO₂/polysilicon cell's performance and optimizing its fabrication process.
(cont.) Chemical mechanical polishing (CMP), a typical planarization method in microelectronics, new to the battery application field, was introduced in order to enhance the cell's properties and performance. LiCoO₂/SiO₂/polysilicon cells consisting of Si0₂ layers 7-40 nm thick were studied. Cells with the planarized polysilicon anode were characterized and the planarization effect was evaluated. This stage demonstrates the importance of interfacial quality in thin film batteries and the advantages incorporation of CMP as a planarization step in the fabrication process. Finally, the third stage of the project focused on applying the thin film technology knowledge and expertise to a more commonly used material system V₂0₅/LiPON/LiCoO₂. With the aim of reducing interfacial roughness, a surface morphology study of V₂0₅ was performed, tailoring different deposition conditions and surface morphology. Implementing the optimized conditions obtained from this analysis, a V₂0₅/LiPON/LiCoO₂ rocking-chair battery was studied next. The cells consisted of approximately 100 or 350 nm thick lithium phosphorus oxynitride (LiPON) electrolyte.
(cont.) This stage demonstrated the advantage of thin film technology in reducing film thickness and the performance enhancement achieved. The work described in this thesis approached the thin film battery subject from the microelectronic perspective, in order to "bring the battery into the clean room".
by Nava Ariel.
Ph.D.
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Chizarie, Anders. "Driving Implantable Circuits Without Internal Batteries." Thesis, Linköpings universitet, Elektroniksystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132595.
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This master thesis investigates how implantable devices can operate without the use of internal batteries. The idea is to be able to drive a circuit inside human tissue to i.e. monitor blood flow in patients. Methods such as harvesting energy from the environment to power up the devices and wireless energy transferring such as electromagnetic induction have been investigated. Implantable devices as this communicates wirelessly, this means that data will be transferred through the air. Sending data streams through air have security vulnerabilities. These vulnerabilities can be prevented and have been discussed. Measurements of the electromagnetic induction have been made with tissue-like material, to see how tissue affects the received signal strength indication levels. Optimization have been made to make printed inductors as efficient as possible by looking at the parameters that have an impact on it. This to get the most out of the inductor, while still keeping it small when it comes implantable devices. Smaller size is better for implantable device.
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Huang, Haitao. "Manganese spinels for rechargeable lithium batteries." Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/13603.
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The synthesis, characterisation and performance of lithium manganese oxide spinels have been studied in terms of their application as cathode materials in rechargeable lithium batteries. A new air stable synthesis based on a solution route has been proposed. Powder X-ray diffraction demonstrates that formation of single phase spinel is possible at temperatures as low as 200 °C. Chemical analysis indicates that the compositions of the spinels prepared by the new solution route depend on the firing temperature. A temperature of 200 °C gives a composition of LiMn2O4.1 and the oxygen content decreases with increasing firing temperature, reaching LiMn2O4 .02 at 600 °C and LiMn2O4 at 800 °C. TEM indicates that the solution based spinels possess small particle sizes, less than 1 ?m. All these characteristics differ markedly from the highly stoichiometric and crystalline spinel prepared by traditional solid state reaction over 800 °C. Electrochemical cells based on the new spinel cathodes were constructed and subjected to galvanostatical cycling at a high discharge rate of C/2 for 300 cycles (charging at C/4). The material fired at 200 °C exhibits excellent performance at 3 V cells. An initial capacity of around 140 mAhg-1 is obtained, very close to the theoretical capacity (148 mAhg-1 ) expected for LiMn2O4 . An enhancement of capacity retention by nearly 50 % after 300 cycles is obtained if < 1 wt % of carbon is added to the solution during synthesis. After 300 cycles, 64 % of the initial capacity remains. The spinel prepared by the solution route and fired at 600 °C gives excellent performance in 4 V cells. An initial capacity of 120 mAhg-1 is obtained and around 75 % of capacity remains after 300 cycles. Ex-situ X-ray diffraction and electrochemical studies such as ac impedance and cyclic voltammetry including the use of microelectrodes were carried out to understand self-discharge and capacity loss on cycling. Spinel dissolution in the electrolyte as well as layer formed on the electrode surface may play an important part in the cycle life of the 4 V spinel cathode. The capacity loss in the 3 V cells arises from incomplete reversibility of the phase transition between cubic and tetragonal spinel which accompanies each cycle.
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Ranom, Rahifa. "Mathematical modelling of lithium ion batteries." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/375538/.
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Zheng, Jingfeng. "Designing Ionic Polymers for Potassium Batteries." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu155508012993124.
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Alam, Tariq Rizvi. "Modeling and Design of Betavoltaic Batteries." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/89648.
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The betavoltaic battery is a type of micro nuclear battery that harvests beta emitting radioactive decay energy using semiconductors. The literature results suggest that a better model is needed to design a betavoltaic battery. This dissertation creates a comprehensive model that includes all of the important factors that impact betavoltaic battery output and efficiency.
Recent advancements in micro electro mechanical systems (MEMS) necessitate an onboard miniaturized power source. As these devices are highly functional, longevity of the power source is also preferred. Betavoltaic batteries are a very promising power source that can fulfill these requirements. They can be miniaturized to the size of a human hair. On the other hand, miniaturization of chemical batteries is restricted by low energy density. That is why betavoltaics are a viable option as a power source for sophisticated MEMS devices. They can also be used for implantable medical devices such as pacemakers; for remote applications such as spacecraft, undersea exploration, polar regions, mountains; military equipment; for sensor networks for environmental monitoring; and for sensors embedded in bridges due to their high energy density and long lifetime (up to 100 years).
A betavoltaic battery simulation model was developed using Monte Carlo particle transport codes such as MCNP and PENELOPE whereas many researchers used simple empirical equations. These particle transport codes consider the comprehensive physics theory for electron transport in materials. They are used to estimate the energy deposition and the penetration depth of beta particles in the semiconductors. A full energy spectrum was used in the model to take into account the actual radioactive decay energy of the beta particles. These results were compared to the traditional betavoltaic battery design method of estimating energy deposition and penetration depth using monoenergetic beta average energy. Significant differences in results were observed that have a major impact on betavoltaic battery design. Furthermore, the angular distribution of the beta particles was incorporated in the model in order to take into account the effect of isotropic emission of beta decay. The backscattering of beta particles and loss of energy with angular dependence were analyzed. Then, the drift-diffusion semiconductor model was applied in order to estimate the power outputs for the battery, whereas many researchers used the simple collection probability model neglecting many design parameters. The results showed that an optimum junction depth can maximize the power output. The short circuit current and open circuit voltage of the battery varied with the semiconductor junction depth, angular distribution, and different activities. However, the analysis showed that the analytical results overpredicted the experimental results when self-absorption was not considered. Therefore, the percentage of self-absorption and the source thickness were estimated using a radioisotope source model. It was then validated with the thickness calculated from the specific activity of the radioisotope. As a result, the battery model was improved significantly. Furthermore, different tritiated metal sources were analyzed and the beta fluxes were compared. The optimum source thicknesses were designed to increase the source efficiencies. Both narrow and wide band gap semiconductors for beryllium tritide were analyzed.PHD
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Nazari, Ashkan. "HEAT GENERATION IN LITHIUM-ION BATTERIES." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1469445487.
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Nwafornso, Tochukwu. "Bismuth anode for sodium-ion batteries." Thesis, Uppsala universitet, Strukturkemi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-449075.
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It is imperative to develop alternative battery technologies based on naturally abundant elements, with competitive performance as lithium-ion batteries. Sodium has a natural abundance 1000 times more than lithium with both lithium and sodium-ion batteries having similar chemistry. Sodium-ion batteries are potentially an alternative that can achieve such competitive performance, given that electrode and electrolyte materials of high rate and long-term electrochemical performance are being developed. This thesis investigates the rate capability and long-term performance of bulk bismuth electrodes containing varying carbon content. The electrodes were cycled in cells with glyme-based electrolytes: diglyme and tetraglyme. Scanning electron microscopy and energy dispersive spectroscopy showed the morphology and elemental mapping of pristine and cycled bismuth electrodes. The result demonstrates the evolving porosity as the electrode cycled. The galvanostatic cycling of half-cells showed two plateaus each for sodiation and desodiation. Also, two peaks are seen in cyclic voltammetry suggesting a two-phase reaction. When cycled between -0.6 to 0.6 V in a symmetrical cell, the bismuth electrode showed an appreciable rate capability at a current rate of 770 mA/g in diglyme. In tetraglyme, it showed a poor rate capability, even at a current rate of 308 mA/g. The rate performance in a full cell cycled between 0.1 to 3.2 V also showed a good rate capability at a current rate of 770 mA/g in diglyme. Tetraglyme showed poor rate capability at the same current rate. The capacity retention was higher in the symmetrical cells, with 79 % and 78 % capacity retention relative to the initial charge capacity after 100 cycles for diglyme and tetraglyme. At the same current rate and more than 70 cycles, the full cells showed capacity retention of 58 % in diglyme and 44.8 % in tetraglyme. The capacity retention varied slightly for the two different electrode composites. The superior performance in the symmetrical cell is due to the narrow voltage window. Evaluating the stability of the solid electrolyte interphase via galvanostatic cycling suggests some stability issues. The full cells showed growing resistance with an increasing number of cycles.
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McTurk, Euan. "Degradation and processes in lithium batteries." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:1cd07380-ac39-4ca2-856d-4903f2a5757a.
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The automotive industry requires rapid advances in battery technology to fulfil the range and price criteria set by its consumer base. Lithium-ion cell chemistries are currently best-suited to this application, but are approaching their maximum practical energy density and have yet to exhibit lifespans that are equivalent to that of the vehicles that they power. Therefore, there is considerable interest in the next-generation lithium-air cell, which promises upwards of a five-fold increase in energy density over today's lithium-ion cells. However, there are many hurdles to overcome, the most important being limited cycle life. Two new organic solvents, namely adiponitrile and glutaronitrile, were investigated as possible new electrolytes for non-aqueous lithium-air cells. Both electrolytes were found to be susceptible to nucleophilic attack by the intermediate O2 radical species, resulting in rapid capacity loss upon cycling and the conversion of the discharge product, Li2O2, to LiOH. As such, these solvents have been ruled out for use in lithium-air applications. Work then focussed on the parameterisation of lithium-air cells to assist the development of a multiscale model of the lithium-air discharge mechanism that incorporates the simultaneous formation of Li2O2 in solution and as a surface layer for the first time. Numerous analytical techniques were used to obtain the oxygen concentration and diffusion coefficient of multiple electrolytes, as well as details pertaining to the cathode structure of the cell. The model was shown to predict the discharge profile of a lithium-air cell with greater accuracy than previous models at low and medium current densities, and will thus be a useful tool for the rapid screening of new electrolyte solutions and cathode structures. Finally, a new 3-electrode modification technique was developed for commercial lithium-ion pouch cells that allows potential profiles of each electrode to be obtained in-situ with no impact upon cell performance, as verified by cycling with unmodified cells and cathode/anode half-cells, and by post-mortem analysis. This technique has provided the data required to experimentally verify a parametric open circuit voltage model for lithium-ion cells that can model and predict electrode-specific decomposition mechanisms to within an accuracy of 10 mV RMSE. Ultimately, the model may be used to improve the effectiveness of a vehicular battery management system and extend the lifespan of the traction battery pack.
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Barrett, Lawrence Kent. "Silicon Carbon Nanotube Lithium Ion Batteries." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6172.
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Silicon has the highest theoretical capacity of any known anode material, and silicon coated carbon nanotubes (Si-CNTs) have shown promise of dramatically increasing battery capacity. However, capacity fading with cycling and low rate capability prevent widespread use. Here, three studies on differing aspects of these batteries are presented. Here, three studies on differing aspects of these batteries are presented. The first examines the rate capability of these batteries. It compares the cycling of electrodes hundreds of microns thick with and without ten micron access holes to facilitate diffusion. The holes do not improve rate capability, but thinner coatings of silicon do improve rate capability, indicating that the limiting mechanism is the diffusion through the nanoscale bulk silicon. The second attempts to enable stable cycling of anodes heavily loaded with silicon, using a novel monolithic scaffolding formed by coating vertically aligned carbon nanotubes (VACNTs) with nanocrystalline carbon. The structure was only able to stabilize the cycling at loadings of carbon greater than 60% of the electrode by volume. These electrodes have volume capacities of ~1000 mAhr/ml and retained over 725 mAhr/ml by cycle 100. The third studies the use of an encapsulation method to stabilize the solid electrolyte interphase (SEI) and exclude the electrolyte. The method was only able to stabilize cycling at loadings below 5% silicon, but exhibits specific capacities as high as 3000 mAhr/g of silicon after 20 cycles.
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Zhu, Juner. "Mechanical failure of lithium-ion batteries." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122143.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-244).
The commercialization of lithium-ion batteries has accelerated the electrification process of vehicles. In the past decade, one could see great advances in the life span, cost, performance, specific energy, and specific power of batteries. At the same time, the safety of batteries has not been adequately addressed by most stakeholders in the Electric Vehicle market. The present thesis systematically investigates the deformation mechanisms of the multi-layered structure of lithium-ion battery cells subjected to various loading conditions with particular emphasis on predicting the onset of the electrical short circuit. It starts with a comprehensive testing and modeling study of all the components of the cell, including the current collectors, the separator, the pouch/shell casing, and particularly, the coatings of electrodes.
A detailed computational model for quasi-static loading is subsequently established in Abaqus/explicit, which is very effective to predict the load-displacement response, peak load, displacement to fracture and short circuit, as well as the shear fracture phenomenon. The computational model is then extended to cover the effect of strain rate dependence by introducing the poro-mechanical theory. Darcy's law is used to describe the flow of the electrolyte inside the granular structure of the coating, and the Kozeny-Carman equation is adapted to calculate the permeability of the porous media of the battery cell. The model is shown to accurately predict the strengthening effect of the battery cell under low-speed dynamic loading, observed in experiments. The effect of mechanical deformations of a battery cell on its electrochemical performance is investigated next through a series of control tests on the coin-cell type batteries made of deformed electrodes.
The batteries are tested with ten cycles of charge-discharge, and a clear capacity fade in the damaged cells compared with the undamaged ones is observed. Electrochemical impedance spectroscopy tests are then performed, and the possible mechanism of the capacity fade is proposed. In the last part of the thesis, two applications of the developed computational modeling strategy are exhibited. One is the axial deformation of the 18650 cylindrical cells, and the other is the protective structural design of EV battery pack subjected to a "ground impact".
by Juner Zhu.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Johansen, Jonathan Frederick. "Mathematical modelling of primary alkaline batteries." Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16412/1/Jonathan_Johansen_Thesis.pdf.
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Three mathematical models, two of primary alkaline battery cathode discharge, and one of primary alkaline battery discharge, are developed, presented, solved and investigated in this thesis. The primary aim of this work is to improve our understanding of the complex, interrelated and nonlinear processes that occur within primary alkaline batteries during discharge.
We use perturbation techniques and Laplace transforms to analyse and simplify an existing model of primary alkaline battery cathode under galvanostatic discharge. The process highlights key phenomena, and removes those phenomena that have very little effect on discharge from the model. We find that electrolyte variation within Electrolytic Manganese Dioxide (EMD) particles is negligible, but proton diffusion within EMD crystals is important. The simplification process results in a significant reduction in the number of model equations, and greatly decreases the computational overhead of the numerical simulation software. In addition, the model results based on this simplified framework compare well with available experimental data.
The second model of the primary alkaline battery cathode discharge simulates step potential electrochemical spectroscopy discharges, and is used to improve our understanding of the multi-reaction nature of the reduction of EMD. We find that a single-reaction framework is able to simulate multi-reaction behaviour through the use of a nonlinear ion-ion interaction term.
The third model simulates the full primary alkaline battery system, and accounts for the precipitation of zinc oxide within the separator (and other regions), and subsequent internal short circuit through this phase. It was found that an internal short circuit is created at the beginning of discharge, and this self-discharge may be exacerbated by discharging the cell intermittently. We find that using a thicker separator paper is a very effective way of minimising self-discharge behaviour.
The equations describing the three models are solved numerically in MATLABR, using three pieces of numerical simulation software. They provide a flexible and powerful set of primary alkaline battery discharge prediction tools, that leverage the simplified model framework, allowing them to be easily run on a desktop PC.
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Johansen, Jonathan Frederick. "Mathematical modelling of primary alkaline batteries." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16412/.
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Three mathematical models, two of primary alkaline battery cathode discharge, and one of primary alkaline battery discharge, are developed, presented, solved and investigated in this thesis. The primary aim of this work is to improve our understanding of the complex, interrelated and nonlinear processes that occur within primary alkaline batteries during discharge. We use perturbation techniques and Laplace transforms to analyse and simplify an existing model of primary alkaline battery cathode under galvanostatic discharge. The process highlights key phenomena, and removes those phenomena that have very little effect on discharge from the model. We find that electrolyte variation within Electrolytic Manganese Dioxide (EMD) particles is negligible, but proton diffusion within EMD crystals is important. The simplification process results in a significant reduction in the number of model equations, and greatly decreases the computational overhead of the numerical simulation software. In addition, the model results based on this simplified framework compare well with available experimental data. The second model of the primary alkaline battery cathode discharge simulates step potential electrochemical spectroscopy discharges, and is used to improve our understanding of the multi-reaction nature of the reduction of EMD. We find that a single-reaction framework is able to simulate multi-reaction behaviour through the use of a nonlinear ion-ion interaction term. The third model simulates the full primary alkaline battery system, and accounts for the precipitation of zinc oxide within the separator (and other regions), and subsequent internal short circuit through this phase. It was found that an internal short circuit is created at the beginning of discharge, and this self-discharge may be exacerbated by discharging the cell intermittently. We find that using a thicker separator paper is a very effective way of minimising self-discharge behaviour. The equations describing the three models are solved numerically in MATLABR, using three pieces of numerical simulation software. They provide a flexible and powerful set of primary alkaline battery discharge prediction tools, that leverage the simplified model framework, allowing them to be easily run on a desktop PC.
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INSINGA, Maria Grazia. "LEAD-ACID BATTERIES WITH NANOSTRUCTURED ELECTRODES." Doctoral thesis, Università degli Studi di Palermo, 2020. http://hdl.handle.net/10447/395216.
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Xu, Feng. "Propriétés thermo-mécaniques des micro-batteries." Paris 6, 2012. http://www.theses.fr/2012PA066549.
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La miniaturisation des dispositifs électroniques a pour conséquence une forte demande de sources d’énergie miniaturisée. Les micro-batteries répondent exactement à cette demande. La micro-batterie que nous étudions avec l’empilement actif de Ti / a-Si / LiPON / TiOS (lithié) / Ti a été élaborée par le CEA-LITEN. Mon travail s’inscrit dans le projet STRESSBAT, soutenu par l’Agence Nationale de la Recherche (ANR), dont le but est d’améliorer des performances électrochimiques et thermomécaniques de ce type de micro-batterie. Comme les propriétés thermomécaniques globales de la micro-batterie dépendent des caractéristiques de ses composants individuels, ma thèse s’organise principalement autour de la caractérisation mécanique et thermique de ceux-ci. Nous utilisons deux techniques de type pompe-sonde: l’acoustique picoseconde et la microscopie de thermo-réflectance. Concrètement, l’acoustique picoseconde nous permet de mesurer la vitesse des ondes longitudinales et des ondes de Rayleigh, et accessoirement la densité du matériau étudié. Ces données permettront de remonter à des paramètres tels que le module d’Young et le coefficient de Poisson. La microscopie de thermo-réflectance nous permet d’extraire conductivité et diffusivité thermiques par l’analyse théorique de la diffusion latérale de la chaleur. Le collecteur de courant Ti, l’électrolyte LiPON, les électrodes TiOS et a-Si ont été étudiés successivement par ces deux techniquesThe miniaturization of electronic devices brings a strong demand for miniaturized power sources. Micro-batteries fit well with this demand. The micro-battery that we studied with the active multilayer system: Ti / a-Si / LiPON / TiOS (lithiated) / Ti has been fabricated by CEA-LITEN. My work is part of the STRESSBAT research project, supported by the French National Research Agency. This project is devoted to the improvement of the electrochemical and thermo-mechanical performances of this type of micro-battery. As the global thermo-mechanical properties of micro-batteries depend on the characteristics of their individual components, my thesis is dedicated primarily to the characterization of mechanical and thermal properties of each of them. We use two techniques both based on "pump-probe" method: picosecond ultrasonics and thermo-reflectance microscopy. Specifically, picosecond ultrasonics allows us to measure the velocities of longitudinal and Rayleigh waves, and if possible, the density of the studied material. These data will help us to deduce some elastic parameters like Young’s modulus and Poisson’s ratio. Thermo-reflectance microscopy allows us to extract the thermal conductivity and diffusivity with the help of the theoretical analysis of lateral heat diffusion. The Ti current collector, LiPON electrolyte, TiOS and a-Si electrodes are studied successively by these two techniques
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Shen, Weixiang. "Advanced battery capacity estimation approaches for electric vehicles /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B24872751.
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Dudezert, Christophe. "Fatigue des batteries Li-ion dans le cadre d'une utilisation véhicule électrique : impact des conditions d'utilisation sur le vieillissement." Paris 11, 2009. http://www.theses.fr/2009PA112350.
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L'essor des batteries Li-ion, ces dernières décennies, a largement contribué à la mise en place de standards en termes de mobilité. La course à la miniaturisation et à la performance a alors priviligié l'élaboration de systèmes de stockages sûrs et à fortes autonomies plutôt que durables. L'utilisation de ces batteries, dans le cadre d'une application automobile, pour lesquels les cycles de vie se définissent sur des périodes de 6 à 15 ans, bouscule ces standards. Vis-à-vis de cette application, le vieillissement est devenu un critère de premier plan dans le choix d'une technologie. De ce constat naît la nécessité de developper des outils théoriques et expérimentaux capables d'évaluer et de garantir une durée de vie en service de la batterie. Étant donné la diversité des usages automobiles, la nécessité d'une caractérisation rapide et la complexité inhérente aux systèmes Li-ion, la problématique du vieillissement d'une "batterie véhicule" a été abordée selon une approche "fatigue" électrochimique, inspirée des études de fatigue mécaniqueThe development of Li-ion, in recent decades has contributed to the establishment of standards in terms of mobility. The demand for miniaturization and performance then favored the develpment of secure storage systems and high autonomy, rather than sustainable. The use of these batteries, as part of an automotive appliaction, for which cycle life are defined for periods of 6 to 15 years, pushes the standards. For this application, aging has become a leading criterion in choosing a technology. From this observation arises the need to develop theorical and experimental tools able to assess and ensure a long service life of the battery. Given the diversity of uses in automotive domain, the need for rapid characterization and complexity inherent in the Li-ion systems, the aging problem of a "vehicle powertrain" has been addressed by an elctrochemical "fatigue" approach inspired from mechanical fatigue studies
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Siniard, Kevin Choe Song-Yul. "Thermal electrochemical dynamic modeling of sealed lead acid batteries." Auburn, Ala, 2009. http://hdl.handle.net/10415/1879.
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Björkman, Carl Johan. "Detection of lithium plating in lithium-ion batteries." Thesis, KTH, Kemiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266369.
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With an increasing demand for sustainable transport solutions, there is a demand for electrified vehicles. One way to store energy on board an electrified vehicle is to use a lithium-ion battery (LIB). This battery technology has many advantages, such as being rechargeable and enabling reasonably high power output and capacity. To ensure reliable operation of LIB:s, the battery management system (BMS) must be designed with regards to the electrochemical dynamics of the battery. However, since the battery ages over time, the dynamics changes as well. It is possible to predict ageing, but some ageing mechanisms can occur randomly, e.g. due to variations of circumstances during manufacturing, and variations of battery user choices. Hence, by monitoring ageing mechanisms in situ, the BMS can adapt accordingly, similar to a closed loop control system. One ageing mechanism in LIB:s is lithium plating. This mechanism signifies when Li ions are electrochemically deposited as metal onto the negative electrode of the LIB during charging, and can induce other ageing mechanisms, such as gassing or electrolyte reduction. The present project has investigated a method for detecting Li plating in situ after its occurrence by both analysing the voltage change over time during open-circuit voltage (OCV) periods after charging and monitoring battery swelling forces. Results show a correlation between a high probability of Li plating and the appearance of a swelling force peak and an OCV plateau. However, results also show a possible correlation between the onset of Li plating and the onset of the swelling force peak, while also showing a greater detectability of the force signal compared to the electrochemical signal. Furthermore, the present results show that the magnitudes of both signals are probably related to the amount of plated Li. The amount of irreversibly lost Li from plating is shown to have a possible correlation with accumulation of swelling pressure. However, to further validate the feasibility of these two signals, more advanced analysis is required, which was not available during this project.Med en ökande efterfråga på hållbara transportlösningar så finns det ett behov av elektrifierade fordon. Ett sätt att lagra energi ombord ett elektrifierat fordon är att använda et litium-jon-batteri. Denna batteriteknologi har många fördelar: t.ex. är dessa batterier återladdningsbara, och de kan leverera höga uteffekter samtidigt som de kan ha ett stort energiinnehåll. för att säkerställa en säker drift av litium-jon-batterier måste batteriets styrsystem vara designat med hänsyn till den elektrokemiska dynamiken inuti batteriet. Dock åldras batteriet med tiden, vilket innebär att denna dynamik ändras med tiden, vilket innebär att styrningen av batteriet måste anpassa sig till denna föråldring. Det är möjligt att förutspå åldring av batterier, men vissa åldringsmekanismer kan ske slumpartat, t.ex. via slumpmässiga förändringar i tillverkningsprocessen av batteriet, eller variationer i användningen av batteriet. Genom att därmed bevaka dessa åldringsmekanismer in situ så kan styrsystemets algoritm anpassa sig utmed batteriåldringen, trots dessa slumpartade effekter. En åldringmekanism hos litium-jon-batterier är s.k. litiumplätering. Denna mekanism innebär att litium-joner elektrokemiskt pläteras i form av metalliskt litium på ytan av litium-jon-batteriets negativa elektrod. Mekanismen kan också inducera andra åldringsmekanismer, t.ex. gasutveckling eller elektrolytreduktion. Detta projekt har undersökt en metod för att detektera litiumplätering in situ efter att plätering har skett, genom att både analysera öppencellspänningens (OCV) förändring med tiden direkt efter uppladdning samt analysera de svällande krafterna som uppstår under uppladdning av batteriet. Resultaten visar på en korrelation mellan en hög sannolikhet för litiumplätering och observationen av en topp i svällningskraft och en platå i OCV-kurvan. resultaten visar också en möjlig korrelation mellan påbörjandet av litium-plätering och påbörjandet av toppen i svällningskraft. Vidare visar även resultaten ett troligt samband mellan signalernas magnitud och mängden pläterat litium. Slutligen visar resultaten också ett möjligt samband mellan irreversibelt pläterat litium och ett svällningstryck som ackumuleras med varje uppladdningscykel. Dock krävs det en validering med mer avancerade analysmetoder för att säkerställa användningsbarheten av dessa två signaler, vilket ej var möjligt inom detta projekt.
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Cheng, Qingmei. "Materials Design toward High Performance Electrodes for Advanced Energy Storage Applications." Thesis, Boston College, 2018. http://hdl.handle.net/2345/bc-ir:108116.
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Thesis advisor: Udayan MohantyRechargeable batteries, especially lithium ion batteries, have greatly transformed mobile electronic devices nowadays. Due to the ever-depletion of fossil fuel and the need to reduce CO2 emissions, the development of batteries needs to extend the success in small electronic devices to other fields such as electric vehicles and large-scale renewable energy storage. Li-ion batteries, however, even when fully developed, may not meet the requirements for future electric vehicles and grid-scale energy storage due to the inherent limitations related with intercalation chemistry. As such, alternative battery systems should be developed in order to meet these important future applications. This dissertation presents our successes in improving Li-O2 battery performance for electric vehicle application and integrating a redox flow battery into a photoelectrochemical cell for direct solar energy storage application. Li-O2 batteries have attracted much attention in recent years for electric vehicle application since it offers much higher gravimetric energy density than Li-ion ones. However, the development of this technology has been greatly hindered by the poor cycling performance. The key reason is the instability of carbon cathode under operation conditions. Our strategy is to protect the carbon cathode from reactive intermediates by a thin uniform layer grown by atomic layer depostion. The protected electrode significantly minimized parasitic reactions and enhanced cycling performance. Furthermore, the well-defined pore structures in our carbon electrode also enabled the fundamental studies of cathode reactions. Redox flow batteries (RFB), on the other hand, are well-suited for large-scale stationary energy storage in general, and for intermittent, renewable energy storage in particular. The efficient capture, storage and dispatch of renewable solar energy are major challenges to expand solar energy utilization. Solar rechargeable redox flow batteries (SRFBs) offer a highly promising solution by directly converting and storing solar energy in a RFB with the integration of a photoelectrochemical cell. One major challenge in this field is the low cell open-circuit potential, mainly due to the insufficient photovoltages of the photoelectrode systems. By combining two highly efficient photoelectrodes, Ta3N5 and Si (coated with GaN), we show that a high-voltage SRFB could be unassistedly photocharged and discharged with a high solar-to-chemical efficiency
Thesis (PhD) — Boston College, 2018
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry