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1
Scott, Paul. "Experimental investigation of a novel design concept of a modular PEMFC stack." Thesis, University of Hertfordshire, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577516.
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The research described in this thesis focuses on the technological and operational aspects of low temperature polymer electrolyte membrane fuel cell (PEMFC) Stacks. The PEMFC is regarded as an ideal replacement to the internal combustion engine, but is still not an economically attractive prime-mover due to a number of key challenges that have yet to be fully resolved. These challenges include; degradation of cell components resulting in inadequate lifetimes, specialised and costly manufacturing processes and poor gravimetric/volumetric energy densities. The design of a novel modular fuel cell stack is presented which attempts to resolve some of the issues relating to material selection and the manufacturing processes required to produce components of the stack. The bi-polar plate (BPP) is a multifunctional component and is responsible for a considerable proportion of stack weight, size and cost in traditional planar PEMFC stacks. The manufacturing processes associated with BPP are costly and often require specialised machining. The design concept removes the conventional BPP from the stack architecture which improves the volumetric and gravimetric energy density of the stack while considerably reducing the cost of the stack. The new architecture comprises of active and passive zones which have focused on specific functionality originally fulfilled by a planar BPP. Active zones are regions that are in direct contact with the membrane electrode assembly and comprise of components that must have both chemical stability and electrical conductivity. Passive regions are designed for gas distribution and structural rigidity of the stack. The architecture involves a series of integrated chambers that supply a single gaseous stock to two cells simultaneously, which are coupled with external manifolds. Electrical continuity is achieved by utilising mono-polar plates that are connected external to the fuel cell stack. A six cell short stack was designed and assembled and the performance of the stack was experimentally tested. Experimental characterisation of the novel stack produced encouraging results. The stack recorded a maximum electrical output of 232.4W and operated over a wide range of operating conditions, including both steady state and dynamic load sequences. Another design feature is the incorporation of a Fault Tolerant System (FTS) as a result of the electrical connections being made external to the fuel cell stack, thus in the event of a cell failure the cell can be made redundant and the stack continues to operate. The FTS was found to operate as envisaged and continued to produce a steady stack output of 3.6V thereafter under this setting. Inspection of the current collecting plates demonstrated degradation on the TiN coating used, with loss of TiN and surface oxidation seen on the coating surface. The severity of the degradation indicated that the TiN coating technique was not suitable for the application. The estimated cost of the stack based on 10,000,000 item quantities was approximately $10.83, while the total weight of the stack was measured to be 2.26kg, resulting in a gravimetric power density of 101W/kg. Significant further weight and cost savings are planned as part of a continual design process.
2
De, Moor Gilles. "Approche multi-échelle des mécanismes de vieillissement des coeurs de pile à combustible." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI049/document.
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Malgré d'importants progrès ces dix dernières années, les piles à combustible de type PEMFC (à membrane échangeuse de protons) souffrent toujours de fin de vie prématurée. Le catalyseur et la membrane, principaux constituants du cœur de la pile, sont les deux éléments principalement mis en cause. Ce travail a pour objectif de comprendre les modes de rupture et de dégradation de la membrane électrolyte durant le fonctionnement. Différents types de vieillissement ont été analysés, à la fois en laboratoire mais également sur des systèmes ayant fonctionné sur site en conditions réelles d'opération (jusqu'à 13000 heures). Au travers une approche multi-échelle (du système macroscopique à l'analyse des propriétés macromoléculaires de la membrane) et d'une utilisation systématique (plusieurs centaines d'échantillons analysés), des scénarios de dégradation ont été établis. Dans un premier temps, des outils de caractérisation macroscopiques ont été spécifiquement développés pour sonder rapidement l'ensemble des cellules d'un stack. Ces outils permettent d'identifier les défauts inter et intra-cellule tout en discriminant les propriétés barrières aux gaz des propriétés d'isolation électronique des membranes, tous deux responsables des courants de fuite en système. Cette approche systématique sur l'ensemble des échantillons a mis en évidence des zones spécifiques favorisant la dégradation prématurée des membranes. Dans un second temps, des caractérisations physico-chimiques ciblées dans ces zones de défaillance ont révélé une dégradation fortement localisée et principalement favorisée par des conditions opératoires spécifiques dans les zones d'entrée des gazIn spite of strong improvements in fuel cell design this last ten years, Proton Exchange Membrane Fuel Cell are still suffering of premature end of life. Failure of the heart of fuel cell, composed of membrane and catalysts, is commonly responsible for fuel cell shutdown. This work brings an original contribution in understanding membrane degradation mechanisms. Different ageing tests were analyzed, in laboratory as well as in real life operating conditions (up to 13000 hours of solicitations). Within a multi-scale approach, from macroscopic to microscopic, and with a systematic usage (hundreds of samples fully characterized), some degradation mechanisms were established. Firstly, macroscopic tools were specifically developed to rapidly track state of health of all the cells from each stack. With the help of these tools, we were able to identify defects inter and intra-cell. It was also possible to discriminate between gas crossover or electronic short-circuit defects, both responsible for current leaks. This systematic approach on each samples put forward some specific areas within the membrane where degradation was promoted. Secondly, physico-chemical characterizations were performed on membrane targeted areas. It was shown that membrane degradation is strongly localized in some specific channels of the bipolar plates and favored by specific operating conditions in the gaz inlets areas
3
Edwards, Tyler A. "A Parametric Study of Stack Performance for a 4.8kW PEM Fuel Cell." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1275667559.
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Frappé, Emmanuel. "Architecture de convertisseur statique tolérante aux pannes pour générateur pile à combustible modulaire de puissance-traction 30kW." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00796139.
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Dans l'objectif d'une augmentation en puissance des piles à combustible pour satisfaire les besoins énergétiques des applications embarquées, une solution consiste à augmenter la taille des assemblages. Dès lors, des problèmes de disparités fluidique, thermique et électrique peuvent survenir dans le cœur des piles et conduire ainsi à l'apparition de défaut. La pile à combustible, de par sa nature de source électrique basse tension - fort courant, requiert d'être couplée au réseau électrique embarqué par l'intermédiaire d'un convertisseur statique. Ce dernier peut alors être employé pour agir de façon corrective sur la pile et aussi de corriger les défaillances qui en sont liées. Dans cette perspective, le convertisseur doit avoir en permanence un retour sur l'état de santé de la pile. Pour cela, une méthode de détection et d'identification de défaut de type noyage et d'assèchement pour une pile du type PEMFC a été approfondie. Cette méthode simple, économique en capteurs, se base sur la mesure de 3 tensions de cellule judicieusement sélectionnées et localisées sur la pile. Ainsi, l'utilisation de l'information " spatiale ", qui correspond à la position de la mesure de tension dans la pile permet d'identifier les défauts. Le principe de la détection localisée nous amène alors à considérer le concept de pile segmentée qui consiste à séparer électriquement la pile en 3 parties de façon à ce que des convertisseurs associés puissent agir électriquement sur chaque segment. L'action peut être du type tout ou rien, ou contrôlée. Cette dernière offre davantage de degrés de liberté, et est moins contraignante pour la pile d'un point de vue électrique. Pour choisir comment réaliser cette action, une étude comparative de plusieurs topologies de convertisseur est effectuée. Les structures alimentées en courant répondent au mieux aux contraintes électriques d'une PEMFC et sont donc privilégiées, de même que la nécessité d'une isolation galvanique imposée par la segmentation de la pile. Au final, une topologie de BOOST isolé résonant est apparue comme étant la topologie répondant au mieux à l'ensemble des critères (plage de fonctionnement, performances énergétiques, nombre de composants). L'ensemble convertisseur global intègre ainsi trois structures unitaires qui permettent d'offrir une modularité, une action indépendante sur chaque segment et de garantir une disponibilité du système grâce à un fonctionnement dégradé. Pour cela, la stratégie de commande de l'ensemble convertisseur intègre les informations issues de la méthode de détection. La thèse se termine avec le dimensionnement complet d'un pré-prototype du convertisseur avec le choix des composants actif et passifs, et du système de refroidissement associé.
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DeLashmutt, Timothy E. "Modeling a proton exchange membrane fuel cell stack." Ohio : Ohio University, 2008. http://www.ohiolink.edu/etd/view.cgi?ohiou1227224687.
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Adiutantov, Nikolai. "Développement d'une instrumentation et méthodologie par l'étude des bruits électrochimiques pour le diagnostic des stacks de pile à combustible de type PEMFC." Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT2313/document.
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Le développement de la technologie « piles à combustible » nécessite l'utilisation d'outils de diagnostic adéquats notamment pour le monitoring de l'état de santé des systèmes industriels (stacks) dans les conditions réelles de fonctionnement. L'utilisation des moyens traditionnels de diagnostic nécessite l'arrêt ou la perturbation du fonctionnement du système. Le travail de cette thèse vise le développement d'une approche innovante non intrusive pour le diagnostic des stacks PEM (Proton Exchange Membrane), basée sur la mesure des petites fluctuations électriques (bruits électrochimiques). Pour mesurer les bruits, un système d'acquisition des faibles signaux à haute fréquence a été utilisé sans filtrage analogique préalable. Ces mesures ont été dans le cadre du projet ANR « Propice » pour quatre campagnes de mesures avec la collaboration du FCLAB et du CEA LITEN. Les mesures des bruits électrochimiques, sur plusieurs semaines, ont permis de construire une base de données extrêmement riche. Pour traiter ces données, différents approches statistiques dans le domaine temporel, fréquentiel et tempo-fréquentiel ont été utilisés pour la génération de descripteurs fiables et robustes. Il a été démontré que la mesure des bruits permet d'obtenir une riche signature des stacks PEM dans un vaste domaine fréquentiel. Cette signature reflète les différents phénomènes physico-chimiques et est très sensible aux paramètres de fonctionnement du système. L'évolution de cette signature au court de temps peut être utilisée pour le diagnostic in-situ de d'état de santé des stacks commerciaux dans les conditions réelles de fonctionnement et pour le développement des moyens de pronosticFuel cell technology development requires adequate diagnostic tools, in particular for monitoring the state of health of industrial systems (stacks) under operating conditions. Traditional diagnostic tools require to stop or disrupt the system operating. This thesis aims at the development of an innovative and non-intrusive approach for the diagnostic of PEM (Proton Exchange Membrane) fuel cell stacks. The methodology is based on the measurement of small electrical fluctuations (electrochemical noise). To measure this noise, a high frequency signal acquisition system was used without prior analog filter. These measurements were obtained within the ANR project « Propice » using four measurement campaigns with the collaboration of FCLAB and CEA LITEN. Electrochemical noise Measurements, over several weeks, made it possible to build a rich database. To process these data, different statistical approaches in time, frequency and tempo-frequency domains have been used for the generation of reliable and robust descriptors. It has been shown that the measurement of noise makes it possible to obtain a rich signature of the PEM stacks in a wide frequency range. This signature reflects the various physico-chemical phenomena and it is very sensitive to the operating parameters of the system. The evolution of this signature in short time analysis can be used for an in-situ diagnostic of the state of health of commercial stacks under real operating conditions and for the development of prognostic strategies
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von, Unwerth Thomas, and Welf-Guntram Drossel. "FC³ - 1st Fuel Cell Conference Chemnitz 2019 - Saubere Antriebe. Effizient Produziert.: Wissenschaftliche Beiträge und Präsentationen der ersten Brennstoffzellenkonferenz am 26. und 27. November 2019 in Chemnitz." Universitätsverlag Chemnitz, 2019. https://monarch.qucosa.de/id/qucosa%3A35720.
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Die erste Chemnitzer Brennstoffzellenkonferenz wurde vom Innovationscluster HZwo und dem Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik IWU durchgeführt. Ausgewählte Fachbeiträge und Präsentationen werden in Form eines Tagungsbandes veröffentlicht.The first fuel cell conference was initiated by the innovation cluster HZwo and the Fraunhofer Institute for Machine Tools and Forming Technology. Selected lectures and presentations are published in the conference proceedings.
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SENNA, ROQUE M. de. "Desenvolvimento e demonstração de funcionamento de um sistema híbrido de geração de energia elétrica, com tecnologia nacional, composto por módulo de células a combustível tipo PEMFC e acumulador chumbo ácido." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10121.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
9
Singh, Hitendra Kumar. "Lifetime Prediction and Durability of Elastomeric Seals for Fuel Cell Applications." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27658.
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Polymer electrolyte membrane (PEM) fuel cell (FC) stacks require elastomeric gaskets for each cell to keep the reactant gases within their respective regions[1]. If any gasket degrades or fails, the reactant gases can leak or mix with each other directly during operation or standby, affecting the overall operation and performance of the FC. The elastomeric gaskets used as FC seals are exposed to a range of environmental conditions, and concurrently, subjected to mechanical compression between the bipolar plates forming the cell. The combination of mechanical stress and environmental exposure may result in degradation of the seal material[2] over a period of time. In order to address the durability and make reliability predictions, the long-term stability of the gaskets in FC assemblies is critical. The aim of this study is to investigate the performance of elastomeric seals in a simulated FC environment in the presence of mechanical stresses. The overall scope of the study includes mechanical and viscoelastic properties characterization, and lifetime durability predictions based on an accelerated characterization approach.
With the help of finite element analysis software, ABAQUS, a fixture was designed to perform strain-based accelerated characterization of seal material in air, deionized (DI) water, 50v/50v ethylene glycol/water solution, and 0.1M sulfuric acid solution. Dogbone samples were strained to different levels in the custom fixture and submerged in liquid solutions at 90°C and in air at 90°C and 120°C. It was observed that mechanical properties such as tensile strength, strain to break, 100% modulus, crosslink density, and tensile set degrade due to aging and the extent of change (increase or decrease) depends significantly on the strain level on the specimen.
Trouser tear tests were conducted on reinforced specimens in air and deionized water (DI) to evaluate the tear resistance of an elastomeric seal material intended for proton exchange membrane fuel cells. Plots relating the crack growth rate with tearing energy were obtained at various temperatures and provided significant insight into the rate and temperature dependence of the tearing strength of the seal material. Stick-slip crack propagation was observed at all temperatures and loading rates, although the behavior was suppressed significantly at low loading rates and high temperatures. Crack growth rate versus tearing energy data at different temperatures was shifted to construct a master curve and an estimate on the threshold value of tear energy was obtained which may be helpful in designing components where material tear is of concern. Strain energy release rate (SERR) value, calculated using the J-integral approach for a pre-existing crack in ABAQUS, was used to estimate the crack growth rate in a given seal cross-section to predict lifetime.
In order to assess the viscoelastic behavior and to investigate the long term stress relaxation behavior of the seal material, compression stress relaxation (CSR) tests were performed on molded seals, called as SMORS, over a range of environmental conditions using a custom-designed fixture. The effect of temperature and environment was evident on material property changes and presented in terms of momentary properties and stress relaxation behavior. Various mechanisms involved in material degradation, chain scission and crosslinking, were suggested and insights were gained into how cure state and level of antidegradants in a material dictate the material behavior during the first phase of environmental exposure leading to change in material properties. Ring samples made of silicone were also tested using the fixture to obtain insight additional into material degradation due to aging. Results presented from testing on SMORS showed a lot more variation in data as compared to neat silicone rings due to the complexity involved in making SMORS.
For understanding the deformation behavior of an elastomeric seal and its sealing performance, finite element characterization of seal cross-section was carried out on O-ring and SMORS cross-section. The effect of a seal's layout on distribution and magnitude of contact stresses and contact width was investigated for the O-ring and the information obtained thereby helped to analyze a complex assembly such as SMORS, where several interfaces and boundary conditions are involved. Stress/strain profiles were generated to visualize their concentration and distribution in the seal cross-section. Frictionless and rough interfacial conditions between seal material and platens were assumed and it was found that its effect on contact width and peak contact pressure was insignificant. Results obtained from FEA on SMORS were validated through comparison with contact mechanics approach and experimental data and it was found that Lindley's equation correlates well with experimental data whereas ABAQUS overestimates the load values at a given compression. Lindley's approach may be used to develop contact pressure profiles that may help estimate peak contact pressure at a given time so leaking can be avoided.Ph. D.
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Wu, Wen-Hsien, and 吳文獻. "Simulation of the PEMFC Stack Model." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/93756382305580658781.
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碩士國立臺灣大學
機械工程學研究所
96
This research is for the purpose of establishing the proton exchange membrane fuel cell （PEMFC） stack model. And the model in this study will be described by the algebraic equation which is different from complex finite element method. The system parameters are accumulated unceasingly to obtain the fuel cell dynamic simulation result and the model can reduce the simulation time. Moreover, this research provides for the PEMFC system developers and experimenters to calculate the performance of the fuel cell and reduce developmental and the experimental time. Besides, we use the MATLAB/Simulink software which is developed by American MathWork Corporation as development kit of PEMFC stack model. According to their physical properties, this research divides PEMFC stack model into three main programs. They contain electrical model, heat transfer model and mass transfer model, and also divide parameters into external parameters, fuel cell stack parameters and dynamic parameters. We program MATLAB/Simulink codes separately for the three models and then confirm the model exactitude. Last but not least, the three models will be combined to form PEMFC stack model, which is used to analysis fuel cell performance with the different input parameters.
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Yang, Su-Bin, and 楊肅斌. "Numerical study for interdigitated micro-PEMFC stack." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/48978845751048183780.
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碩士國立中山大學
機械與機電工程學系研究所
98
According to the previous experimental fact that an interdigitated single PEMFC has a better performance than other flow type single PEMFC, therefore this research is aimed to predict a two-cell stack interdigitated PEMFC via a numerical simulation. Investigation the effects of the cell temperature, the cell operating pressure, the fuel flow rate and the air flow rate are performed. This research can provide design reference for application of interdigitated PEMFC stack.
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Chia-HsienKang and 康嘉顯. "Performance of kW-scale Water-cooled PEMFC Stack." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/4kqqvv.
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碩士國立成功大學
航空太空工程學系
103
In this study, a kW-scale water-cooled PEMFC stacks is designed and tested under different conditions, including fuel conditions, inlet water temperatures , inlet water flow rates, in order to understand effects of the above three parameters on the stack performance and impedance. Based on the qualitative analysis of the experimental results, the gas parameters and thermal management conditions which make the water-cooled PEMFC stack best to be uniform thermally are applied to the stack. The experimental results show that the best performance of this stack, 1431 Watts, and its power density, 694.8 mW/cm2 is exhibited at the inlet water flow rate of 5 L/min, the inlet water temperature of 55oC, the hydrogen stoichiometric ratio of 1.5, the air stoichiometric ratio of 3.0, the air dew point temperature of 65oC. And the maximum power generating efficiency is up to 40.6 %. In addition, with increasing the inlet water temperature and decreasing the inlet water flow rate will decrease the charge transfer resistance because elevated stack temperatures improve the electrochemical reaction. However, the Ohmic resistance rises due to membrane dehydration at elevated stack temperatures. It is also noticed that the stack performance changes significantly with temperature operating conditions at low inlet water flow rates owing to significantly non-uniform temperature distributions over the stack. As a result, the inlet water temperature becomes a critical operational parameter at low inlet water flow rates.
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Huang, Chun-Hui, and 黃竣輝. "Simulation study for a stack of micro-PEMFC." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/af5ehg.
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碩士國立中山大學
機械與機電工程學系研究所
96
Proton exchange membrane (PEM) fuel cell possesses the characteristics of microminiaturization and low temperature operation. For this reason, the proton exchange membrane fuel cell is very suitable to serve as power source of portable electronic products. In this paper, a three-dimensional numerical model to evaluate the voltage and the total current density of a PEM fuel cell stack was developed. The polarization curves of the PEM fuel cell stack under three different operating temperatures were investigated. In this study, the micro PEM fuel cell stack contains two single cells. Pure H2 gas stream was supplied as the anode inlet flow and air as the cathode inlet flow under constant pressure at 97 kPa and constant cell temperate (298K、308K、323K) conditions. Because the cell temperature may affect the chemical reaction rate on the cathode side, we discussed the influences of different temperatures on the cell performance. Solutions were compared with the experimental data. Both the value of power density and the tendency of polarization curve are in good agreement with the experimental data.
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Biak, Martin, and Unwerth Thomas von. "Fit-4-AMandA – Automation of PEMFC-Stack Manufacture." 2019. https://monarch.qucosa.de/id/qucosa%3A36264.
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An EU-funded project Fit-4-AMandA aims to establish a technological roadmap to scale-up from less than hundred stacks/year (manual assembly) to 50,000 stacks/year (automated assembly) in 2020 and beyond. Existing membrane-electrode assembly (MEA) and stack were redesigned/adapted for manufacturability and automation. The technology and machine system for the automated assembly of polymer-electrolyte-membrane fuel cell (PEMFC) stacks were developed, manufactured and are currently being tested. Fast in-line non-destructive quality-assurance methods for automated production of MEAs and stack assembly are being developed and implemented. For the final period of the project, a validation of the designs, hardware, tools and software for the automated production of MEAs and stack assembly as well as an integration of one of the prototype stacks manufactured by the automated processes into a light-commercial vehicle followed by a field-testing are scheduled.Die breite Markteinführung von wasserstoffbasierten Antriebssystemen verlangt zunehmend nach einer kosteneffizienten und serientauglichen Produktion von Brennstoffzellenstacks. So sehen die Ziele der Europäischen Union vor, die Herstellung von aktuell unter 100 Stacks pro Jahr auf 50.000 Stacks pro Jahr bis zum Jahr 2020 zu erhöhen. Um dies zu erreichen, sollen im Rahmen des vom Fuel Cell and Hydrogen Joint Undertaking (FCH JU) der europäischen Union geförderten Projektes Fit-4-AMandA automatisierte Anlagen für solche Stückzahlen befähigt werden. Der Beitrag beschreibt, wie die bereits verfügbare Membran-Elektroden-Einheit (MEA) und der Stack bezüglich Herstellbarkeit und Automatisierung konstruktiv umgestaltet und angepasst wurden. Die neu entwickelte Technologie und das Maschinensystem für die automatisierte Montage von PEM-FC-Stacks sowie Verfahren der INLINE-Qualitätssicherung und der zerstörungsfreien Prüfung werden mit ihren Implementierungsmöglichkeiten in die automatisierte Fertigungsstrecke vorgestellt. Ein Ausblick gibt eine Übersicht über die weiteren Entwicklungsschritte wie die Validierung der Entwürfe, der Hard- und Software für die automatisierte Produktion der MEAs und Stacks. Eine vorgesehene spätere Integration der so gefertigten Stacks in ein Fahrzeug und die damit verbundenen Feldtests zur Untersuchung der Reproduzierbarkeit und Zuverlässigkeit der Stacks werden abschließend dargestellt. Die Förderung des Projektes erfolgt im Rahmen der Finanzhilfevereinbarung Nr. 735606 des FCH JU der EU.
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Yang, Shih-cheng, and 楊仕丞. "The assembly and testing of a PEMFC stack." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/21129355263905644751.
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碩士國立中山大學
機械與機電工程學系研究所
102
The design of bipolar plates and the manufacturing of electrodes are critical to the fuel cell performance. Therefore, this study has following two aspects: (1) The design and fabrication of a new bipolar plate; (2) Changing the spraying scheme in preparing the electrode. In producing the bipolar plate, carbon fiber is used as the current collector, with the other parts of bipolar plates made by 3D Printer, and, then, completed with adhesive and compression. Since carbon fiber is soft, the contact resistance can be reduced. And it has some other advantages: the corrosion resistance of acid and alkali, light weight, and cheap. Therefore, the carbon fiber has a great potential to be the material of the bipolar plate. The other components of the bipolar plate are made from 3D Printer. The development of component is quick and easy by using 3D Printer. Especially suitable in the experiment stage. With different catalyst spraying schemes, the catalyst structure will vary, and, subsequently, the cell performance. The increasing in the coverage of carbon fiber on the electrode can improved the fuel cell performance significantly. With the narrowing of distance between fiber bunches and the increasing in carbon fiber, we are able to improve the performance of the fuel cell in experiment.
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Mérida, Donis Walter Roberto. "Diagnosis of PEMFC stack failures via electrochemical impedance spectroscopy." Thesis, 2002. https://dspace.library.uvic.ca//handle/1828/10312.
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Two failure modes related to water management in Proton Exchange Membrane fuel cells (dehydration and flooding) were investigated using electrochemical impedance spectroscopy as a diagnosis tool. It was hypothesised that each failure mode corresponds to changes in the overall stack impedance that are observable in different frequency ranges. This hypothesis was corroborated experimentally.
The experimental implementation required new testing hardware and techniques. A four-cell stack capable of delivering individually conditioned reactants to each cell was designed, built, tested, and characterised under a variety of operating conditions. This stack is the first reported prototype of its type.
The stack was used to perform galvanostatic, impedance measurements in situ. The measurements were made at three different temperatures (62, 70 and 80°C), covering the current density range 0.1 to 1.0 A cm−2 , and the frequency range 0.1 to 4 × 105 Hz. The recorded data represent the first reported set of measurements covering these ranges.
The failure modes were simulated on individual cells within the stack. The effects on individual cell and stack impedance were studied by measuring the changes in stack and cell impedances under flooding or dehydration conditions.
Dehydration effects were measurable over a wide frequency range (0.5 to 105 Hz). In contrast, flooding effects were measurable in a narrower frequency range (0.5 to 102 Hz). Using these results, separate or concurrent impedance measurements in these frequency ranges (or narrow bands thereof) can be used to discern and identify the two failure modes quasi-instantaneously. Such detection was not possible with pre-existing, do techniques.
The measured spectra were modelled by a simple equivalent circuit whose time constants corresponded to ideal (RC) and distributed (Warburg) components. The model was robust enough to fit all the measured spectra (for single cells and the stack), under normal and simulated-failure conditions.
Approximate membrane conductivities were calculated using this model. The calculations yielded a range from 0.04 to 0.065 S cm−1 (under normal humidification), and conductivities that deviated from these nominal range under flooding or dehydrating conditions. The highest conductivity value (was ∼0.10 S cm−1) was measured under flooding conditions at j = 0.4 A cm−2. The lowest conductivity (∼0.02 S cm−1) corresponded to a dehydrated cell at j = 0.1 A cm−2. These values fall within the ranges of published data for modern proton exchange membranes.
The phenomenological and numerical results reported in this work represent the first demonstration of these techniques on a PEMFC stack under real operating conditions. They are also the basis of ongoing research, development, and intellectual property protection.Graduate
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wei-chifung and 方瑋琦. "Experiment and Numerical Simulation of a Small PEMFC Stack." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/89613294409810501282.
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碩士國立成功大學
航空太空工程學系碩博士班
98
This work is aimed to study the characteristics of a single proton exchange membrane fuel cell (PEMFC) and a small two-cell stack through experiments and numerical simulations. Notably, the three dimensional numerical model used is of full size (97.75 cm2 reaction area/single cell). A commercial computational fluid dynamics software, CFD-ACE+, is used as the solver in this report. The Navier-Stokes equation is coupled with the energy, species, and the electrochemical equations. Therefore, mass, momentum and species transport phenomena as well as the electron- and proton- transfer processes in a PEMFC cell/stack are solved simultaneously. Experimental results of the polarization curves are used to validate the numerical results. Good agreements are observed for both single cell and two-cell stack. The present results show that the electrochemical reaction is faster at low-voltage and high temperature condition, by which leads to the results of fast reduction of the reaction gas and makes fuel deficiency appear around the outlet. These results can be important issues in the real engineering for improving the performance of the fuel cell. Flow phenomena in the full-size fuel cell/stack can be observed by the simulation results which are difficult to be obtained in experiments. The future work is to increase the number of cells in the stack in the numerical simulations and to decrease the computational time for a cost- and time-effective engineering development.
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Lee, Kun-Cheng, and 李焜正. "Studies and Developments of a High Efficiency Portable PEMFC Stack." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/17605434732170567977.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
98
In this thesis, a portable PEMFC stack, which can directly power or charge 3C products, will be developed. The stack is developed for portable applications, so the structure of the stack is simplified as possible as we can. The PEMFC stack is made with 32 carbon fiber bunches for current collectors and two 8-cell banded-type MEAs which are made with 8 sets of electrodes on a piece of membrane. The stack can develop a high voltage by serially connecting 8 cell or 16 cell outside of the reaction chamber. The resistance of each carbon bunch assembling with carbon cloth is measured before they are assembled into the stack. Under assembly pressure 3 bar, the total resistance is about 8.7mΩ or 11mΩ‧cm2. The resistance is about one half of that graphite plate assembling with carbon cloth. Without being compressed greatly in diffusion layer, the fluid can easily flow through the gaps between carbon fiber and within diffusion layers, and then the reactive region will react more uniformly. In addition, the connecting wires are assembled to a wire collecting board, so that the stack is look more neat, and it easier assemble or dissemble. In this thesis, the volume of the developed 16-cell hydrogen fuel cell stack is about 9.6 cm*6.3 cm*2.2 cm. The total electrode area is 50 cm2 (16-cell×3.15 cm2 per cell). When the stack is operating at room temperature and air-breathing, an 8-cell stack in series connection can generate 3.7V voltage. Its power at voltage 3.7V is about 3.6W. It can directly power PDAs, mobile phones or digital cameras. A 16-cell stack in series connection can generate 7.2V voltage. Its power at this voltage can offer 7W. The 16-cell stack can directly power digital single-lens reflex cameras. If two or more of this stack are connected in series, it will be able to power a notebook or other more power products.
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Sheu, Ning-Yih, and 許寧逸. "Innovative Design and Experimental Studies of Flat Type PEMFC Stack." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/90139722687615220481.
Full textAbstract:
碩士國立臺灣大學
化學工程學研究所
88
A growing number of consumer electronics need small, portable and lightweight power supplies with high power density and energy density. In this study, a novel design of flat type PEMFC stack was fabricated by using acrylic plates instead of stainless end plates and composite graphite gas flow field plates to largely reduce the weight of stacks and their production cost. Furthermore, using conducting pastes to make current collectors instead of copper plates the weight of the stack could be greatly reduced. In this study, the membrane electrode assembly (MEA) was fabricated by using a new catalyst layer process with Pt loading of less than 0.2 mg/cm2. The single cell test performance of MEA with this new process was found to be better than the traditional process and could be comparable to that of electrodes made by E-Tek. Cyclic voltammetry results of the new MEA were obtained and the results was compared with those made by traditional process and E-Tek electrodes. The preliminary experimental results of the flat-type PEMFC stack show that its peak power density is 100 mW/cm2 operated by dry hydrogen and oxygen at ambient pressure and room temperature in order to eliminate the bulky supporting systems such as compressors or humidifiers.
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Lin, Yu-Sheng, and 林育昇. "Influence of Clamping Force on the Performance of PEMFC Stack." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/27659303454427272871.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
96
Recently, there is a tendency toward larger reactive area and higher current in PEMFC stack design. The design of assembly of a PEMFC stack becomes much more complex and important than just a single cell. The assembly mechanism will affect the contact behavior between bipolar plates and membrane electrode assemblies （MEAs）and hence the performance of PEMFC stack. Inadequate clamping pressure may lead to leakage of fuels, high electric impedance and malfunction of the cells. On the other hand, excessive clamping pressure may destroy the MEA. This study is to study the PEMFC stack design and its clamping pressure distribution, using the pressure sensitive film (FUJI-FILM I&I) to measure the clamping pressure between the reactive area and the bipolar plates under different bolt-clamping configurations and different clamping forces. According to the experimental results, the stack performance and the pressure’s distribution is greatly influenced by the clamping force and the bolt configuration. The experimental results further our understanding of the effects of clamping conditions on the performance of a PEMFC.
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Lee, Te-Hsuan, and 李德軒. "Development of a Passive Hydrogen PEMFC Stack for 3C Products." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/na2p6a.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
102
In this thesis a portable passive hydrogen proton exchange membrane fuel cell (called PEMFC) stack is developed to drive or charge 3C products without any transformer. We divide our research into two stages. One is the characteristics study of a 2-cell PEMFC stack. The other is the characteristics studies and the applications of a 16-cell PEMFC stack. In the 2-cell stack, the effects of water content within proton electrode membrane on the performance of the stack are studied. In general, the cathode of MEA completely expose in the atmosphere so that the water is easily diffusing and evaporating into air. This phenomenon will cause water shortage and reduce the conductivity of proton within the membrane. Therefore, we add a water chamber within anode to supply water to make-up the evaporated water during long-period operation. The next, the effects of the storage methods of MEA on the stability and the performance are studied. After studies of a 2-cell stack, we design and make a 16-cell stack. The rating voltage of this stack is 5 V. The maximum power output is about 10 W. The range of the power can drive or charge the most 3C products. The 16-cell stack can be series and/or parallel connected with different number of cells so that it can drive or charge a mobile phone, a pad, and a digital photo player without a transformer. The future commercial stack will directly drive or charge any 3C products with power less than 10 W.
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Chen, Chen-Yu, and 陳震宇. "Studies on The Design of Air-Breathing Miniature PEMFC Stack." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/66655268185758083295.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
93
Proton exchange membrane fuel cells (PEMFC) are one of the most interesting alternatives for clean power production in automotive applications and for distributed power generation. PEMFC might also be a viable alternative in many special applications where a highly reliable source of electricity is needed and a miniature PEMFC will be a good electricity source of MAVs, robots or other small applications. In this study, an air-breathing miniature PEMFC stack with a dimension of 6 cm length, 6 cm width and 3 cm thickness has been designed. A mono-polar assembly method is applied to connect 10 single cells with a 1.7 cm2 electrode area in each single cell and the stack is composed of several layers including a proton exchange membrane with 10 segmented electrode coated area, sealing layers, collector plates, a ventilation plate, a fuel flow field plate, a fuel distributor and end-plates. To provide the flexibility of electrics connection of 10 single cells, the flow field plate is fabricated with acrylonitrile-butadiene-styrene (ABS) material to ensure electricity isolation between each single cell. In this study, the rapid prototyping (RP) technology have been firstly applied to manufacture the flow field plates of the fuel cell stack. Rapid prototyping utilize CAD data which is transformed from a design concept to CAD data by computer integrated manufacturing (CIM) technology to forming the 3D model to accelerate the new product development. This technology reduces producing and processing difficulties, and allows manufacturing to proceed as long as 3D CAD design file has been completed. RP method fast connects product design and manufacturing, without conventional NC code editing and considerations in finding available fixtures. An MEAs polarization curve test under the conditions of 70℃ cell temperature, 70℃RH humidified H2 and O2 and closed flow channel has been completed and a current density 960 mA/cm2 at rated voltage output of 0.6V has been obtained. The polarization curve test under the conditions of room temperature environment, forced convection of air, . 90℃ R.H. humidified H2, has been completed. A power density of 188mW/cm2 at 0.425V in the parallel-connection tests and a power density of 123mW/cm2 at 4.25V has been obtained in the serial-connection tests.
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Wei-FengHong and 洪偉峰. "Design and Performance Test of a Water-Cooled PEMFC Stack." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/31640098721459481875.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
101
There are several technical obstructions to overcome for the commercialization of PEMFCs. One of the most critical issues is the water and thermal management which has been considered a key factor to an uniform electrochemical reaction and a proper water content in the MEA. There is a considerable amount of heat while operating a stack, especially at a high current density. The waste heat could lead to dehydration of the MEA locally or globally if an improper thermal management. In this work, a 5-cell liquid-cooled PEMFC stack was designed and developed. In the beginning process of stack design, ANSYS CFX simulation is adopted. Our primary mission focuses on the investigation of stack characteristics, including stack performance and impedance analysis in terms of gas stoichiometric ratio, gas humidification, cooling water temperatures and cooling water flow rates, A cooling plate pattern with the best temperature distribution is selected according to our simulate qualitative analysis. The experiment results show that increasing the cooling water temperature significantly raising the stack performance due to an increase of the rate of electrochemical reaction. The 5-cell water-cooled PEMFC stack exhibited the best performance at a water flow rate of 2 L/min, a water temperature of 65 oC, an air stoichiometric ratio of 2.5 and a hydrogen stoichiometric ratio of 1.5. The outside temperature distribution of the stack and the temperature difference between inlet and outlet water change as the output load changes. At a water flow rate of 1 L/min, a higher temperature was observed at a position close to the 3rd and 4th cells. At this condition, the temperature difference between inlet and outlet water is about 6 oC. However ,the area affected by the local high temperature can be reduced effectively by increasing the water flow rate. Increasing the stack temperature increases the Ohmic resistance, but decreases the sum of charge transfer resistance and mass transfer resistance. In addition, the phenomenon of resistance raise becomes less significant for ROhm but more significant for Rct+Rmt at a higher current. This can be attributed to more amount of generated water.
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Hsu, Che-Jung, and 許哲榮. "Design and performance analysis of metal bipolar plate on PEMFC stack." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/52450341805798282836.
Full textAbstract:
碩士元智大學
機械工程學系
98
In this study, we used low-cost, lightweight aluminum alloy bipolar plate on proton exchange membrane fuel cell(PEMFC) stack. Aluminum alloy has good heat Thermal conductivity and mechanical strength. But, aluminum alloy surface oxides lead to poor conductivity, high contact resistance. So we using Au-coated on aluminum alloy bipolar plate surface. Assembled into a single cell and 4-cells stack to measure performance. At H2/Air stoichimotry 1.2/4.0 and humidification temperature of 60 ℃ for best performance by single cell 61.6W and stack maximum power 286W. The dynamic load test had a good response. Finally, the metal bipolar plate to set a long-term test to ensure the stability of the single cell output is no recession.
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Chen, Shu-Bin, and 陳書斌. "Studies on the Stack Design of the Flat-Panel Series PEMFC." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/q7989n.
Full textAbstract:
碩士國立虎尾科技大學
車輛工程系碩士班
100
The purpose of this thesis is to modify the traditional fuel cell stack design, assembly and stack to develop a modulized planar proton exchange membrane fuel cell (PEMFC) stack. In this study, Flip-Flop plane cascading concept is used to design bipolar plate and cascaded composition of the cell stack is used to obtain a higher voltage output. Besides, the combination of the stack pack is applied in the fuel cell stack system to achieve the advantages of easy maintenance and higher scalability. In the stack experiment, the stack is tested to find the best fuel flow, when hydrogen is 600sccm and Air 1200sccm. The result shows that the prototype stack maximum power density of the stack can reach to 1091.93 mW/cm2 at 2V, achieve the 74.29% performance of single cell test kit.
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Jheng, Yi-Ting, and 鄭儀婷. "The Effects of Clamping Force on the Efficiency of PEMFC Stack." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/jcubk9.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
106
The purpose of this study is to investigate the effect of bolt pre-loading variation (5-20MPa) on the efficiency of PEMFC (Proton Exchange Membrane Fuel Cell). In this work, the value of contact resistance and porosity of GDL (Gas Diffusion Layer) are the important factors to judge performance. A 3D FEM (Finite Element Method) model of a complete PEMFC stack was developed incorporated with the commercial software ANSYS 15.0. This stack consisted of one to four cells, and then explored the effect of bolt pre-loading variation on the efficiency of PEMFC with the electrochemical simulation Fluent 15.0. The PEMFC module with an active area of 9cm^2 were composed of end plates, current collectors, bipolar plates, membrane, catalyst layer, and gas diffusion layer. And a PEMFC stack was assembled from a number of repeated units of membrane electrolyte assembly (MEAs) and bipolar plates. All elements were fixed by 8 pairs of bolts and nuts. The fixed nuts and bolts were pre-tensioned by the ANSYS built-in function. From the results of analysis, both contact resistance and porosity of GDL were decreased with the increasing of bolt pre-loading. In a 1-4cell PEMFC, the contact resistance was decreased 61.07%. The decreasing of contact resistance can lead to the ohmic losses and the increase of efficiency for PEMFC. However, the porosity was decreased 18.84%. The decrease of porosity of GDL will lead to the increase of resistance of permeability and result in the reduction of efficiency for PEMFC. The power density of the 1-4cell module was increased by 21.1% while the bolt pre-loading increasing. It is found that the bolt pre-loading of 10MPa is an optimal value for each fuel cell system. Then, we not only get the best conductivity, but also increase the gas transmission resistance. That provides the combination of low contact resistance and good porosity can obtain the maximum power density.
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Wang, Chun-Lin, and 王俊麟. "High performance open cathode PEMFC stack development for lightweight UAV applications." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/31538423056620979074.
Full textAbstract:
碩士元智大學
機械工程學系
105
The lightweight unmanned aerial vehicle (UAV), integrated network of things, artificial intelligence, sensors and new energy technologies, is one of the future innovation industry, which can be applied to the military, commercial and entertainment industry. Such as aerial photography, agriculture, environmental and traffic monitoring VAV machines, and the most critical future network transport service UAV. Among them, the energy technology, how to use fuel cells to extend flight time can be more practical for the logistics industry and long-time detection applications. The high power density of fuel cell module (> 500W / Kg) and the high energy density of hydrogen storage technology (> 5wt%) are required in the range of 50 ~ 300W for the modularized fuel cell power system. Although the current fuel cell vehicle technology has exceeded this specification, but in the small watt system, there is no mature commercial fuel cell technology and products. The membrane electrodes used in open cathode stacks and required high-performance at low-humidity environments, which are used in prototypes of companies such as Intelligent Energy EnergyOR, Horizon fuel cell Tech., Etc. or literatures. In addition to reducing the size of the power pack and system, it also need to reduce its weight and costs of parts. This technology and products also may be applied to other portable power and lightweight mobile carriers. The goal of the project is to build a research and development platform for this unmanned fuel cell stack and component technology, integrating parts and systems technology from Taiwan’s academic and industrial technology to enhance the power density, stability and longevity of UAV applications. A collection of personal expertise in the low-temperature diffusion layer and fuel cell technology, as well as industry components such as carbon energy technology Co. of carbon paper and Yang-ze Tech.CO. of membrane electrode assemblies, and the Asia-Pacific fuel cell technology Co. on the fuel cell stack and system experience, used in this high-performance open cathode type fuel cell stack design. The first year, the establishment of open cathode stack design, and testing of domestic and foreign component materials, so that the fuel cell power density can be up to 300W / Kg. The next year, the improved fuel cell stack and system design, has high performance, stability and life time, and also improved material component technology to have optimized stable power performance> 500 W / Kg, and its low humidity MEA has power density of 500mW / cm2.
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Pai, Jen-Hao, and 白仁豪. "Metal bipolar plates for PEMFC fuel cell stack of the development." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/74922376737659387041.
Full textAbstract:
碩士國立勤益科技大學
機械工程系
101
The main goal of this study is to develop a 5-cell PEMFC stack with SUS 316L stainless steels as bipolar plates with high cell efficiency and power density. The Cell performance test is carried to obtain the optimal operation parameters. The SUS316L is chosen as the plate material because of its excellent corrosion resistance. This study applies micro-electrical discharge machining to fabricate unipolar and bipolar plates. The flow field is serpentine in a reaction area of 34.4×34.4mm2(about 12 cm2), with the channel width of 0.8mm, rib width of 0.6mm. Plates with two different channel depths (0.4mm and 0.6mm) are fabricated for comparison. The bipolar plates are assembled in series to become cell stacks. The performances of cell stacks are evaluated based on parameters such as channel depths, cathode flow rates, and fuel humidification. We successfully develop an 8×8×32cm 5-cell PEMFC stack with the reaction area of 12 cm2 for each cell unit based on series connection. The result shows that the peak power for the 5-cell stack is 17.6W for the channel depth of 0.4mm, and pure air without humidification as the cathode inlet. For cell stack with channel depth of 0.6mm, the peak power is 16.1W. The cell stack with the channel depth of 0.4mm yields better results than that .of 0.6mm. For the results respect to the flow-rate test, the cell performance increases with the increase of flow rate. The cell stacks with cathode flow rate of 1200c.c./min yield best result. As respect to the humidification test, the results show that the cell performance increases with cathode humidification. For the cell stack with 0.4mm channel depth, the peak power is 20.6W for the humidification temperature of 60℃. Under similar condition, the cell stack with 0.6mm channel depth yields 19.4W of peak power. The peak powers increase about 18.1% and 20.5% for the channel depths of 0.4mm and 0.6 mm, respectively, comparing to those without humidification.
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Chang, Jui-Heng, and 張瑞珩. "Applying Intelligent Parameter Design To The Experiment Study Of PEMFC Stack." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/94056760460994484262.
Full textAbstract:
碩士國防大學理工學院
造船及海洋工程碩士班
100
The purpose of this paper is to apply intelligent parameter designs to study the Performance of PEMFC stack in different combinations of the cell temperature, the humidification temperature of anode reaction gas, the humidification temperature of cathode reaction gas, the stoichiometric flow ratio of anode reaction gas and the stoichiometric flow ratio of cathode reaction gas. Expecting the power in the fixed-load is higher, and in the same time, the pressure drop of import and export is lower. The content of the study includes：(1) To design and product the fuel cell stack. (2) To experiment with design of experiments. (3) Applying Taguchi method to analyze the factor level combinations. (4) To verify with the application of principal component analysis. (5) To combine backpropagation neural network and genetic algorithm to find the best solution. Finally, this work determined the best parameters combination by the reduction percentage of quality loss (RPQL). Through analysis of the Taguchi method, principal component analysis and intelligent parameter design, the results showed that the RPQL values of the Taguchi method, principal component analysis and intelligent parameter design were 32.03%, 31.61% and 32.35% respectively more than the original design. Therefore, this study has proved that intelligent parameter design was able to solve the multi-quality problems of both the electric power and the cost.
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Meng-HanLiu and 劉孟翰. "Study on Performance of PEMFC Stack Design with Stainless Steel Bipolar Plates." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/admbu4.
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Tsai, Che-Yin, and 蔡則胤. "The Study of Activation Simulation and Dynamic Data Acquisition of PEMFC Stack." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/37282325404298549838.
Full textAbstract:
碩士銘傳大學
電子工程學系碩士班
101
PEMFC is a kind of new energy. The advantages of PEMFC includes high efficiency, wide application, low pollution, high utility of product, multiple fuel, wide power range and high portability. In terms of theoretical simulation, we could significantly avoid mistakes of designing as well as fabricating a PEMFC stack. Generally, there are two simulation models such as basic mathematical model and GSSEM model. However, the two models are lack some considerations of operational stack. So we propose an improved GSSEM model by adding some parameters including stack activation process, flow design, assembly methods, temperature variation and dead zone to improve the model. Comparing to the experimental results, the error of our simulated results based on our model is less than 10%. In order to obtain the data during fuel cell stack operating, we need to continuously measure and record the relative parameters. Therefore, we developed a fuel cell monitoring system and a hydrogen sensing system. The monitoring system allows users to observe the operation of the stack output voltage, current, temperature and power. The hydrogen sensing system can observe the concentration of hydrogen to keep in safe range.
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Chen, Jion-You, and 陳俊佑. "Design and performance analysis of metal bipolar plate on kW-class PEMFC stack." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/44592178098472552820.
Full textAbstract:
碩士元智大學
機械工程學系
99
In this study, we used aluminum alloy bipolar plate on proton exchange membrane fuel cell(PEMFC) stack. Aluminum alloy has good heat thermal conductivity and mechanical strength than graphite. But the aluminum alloy surface oxides not only stuck the flow channels plate also make poor conductivity, high contact resistance at high humidity states. So we using Au-coated on aluminum alloy bipolar plate to ensure surface stabilize. Assemble 20-cells stack to measure the performance. In H2/Air stoichimotry 1.2/5.0 and humidification temperature of 60 ℃ for best performance can reach 1,201 kW. In low load (10A) and high load (60A) long-term tests, the overall performance of the stack is only 1% and 2% decay. Finally, after the stack connected to external system at low humidity and low fuel stoichimotry the stack net power output can reach 700W.
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Tanadumrongsak, Katayuth, and 陳毓麒. "Study of proton exchange membrane fuel cell stack with piezoelectric fan (PZT fan-PEMFC)." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/29748576429312264889.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
100
The novel PZT-fan design in pseudo-bipolar for a proton exchange membrane fuel cell stack with piezoelectric fan has been developed to generate air supply with high flow rate to initiate the chemical reaction in the cells, and simultaneously push away byproduct e.g. water; that will cause water-flooding within the cells stack. In this design, PEMFC stack contains 24 cm2 of reaction area in six separated fuel cells. This pseudo-bipolar design contained six inside cathodes and six outside anodes to share common piezoelectric fan. The experiment results have shown that the best performance is occurred at the second mode harmonic resonance frequency of piezoelectric fan which used less than 0.15W of power consumption. Relative humidity of hydrogen, cathode chamber thickness and non-piezoelectric blade thickness will affect the PEMFC relative humidity, the indicator of PEMFC performance. The appropriate condition at 50°C for this design is 57.9% of hydrogen relative humidity, 3cm of cathode chamber thickness and 0.1mm of non-piezoelectric blade thickness. In this design, the fuel cell stack with electrical cascade performed better than fuel cell stack with electrical parallel. The results show that maximum power density of PZT fan-PEMFC is 227.5mW/cm2at 2.085Amp. Moreover, the maximum power density shown above is feasible and consistent for approximately one hour in the durability test.
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Lien, Jim, and 連晉. "Studies on the Stack Design of the Miniature Double-Planar Array Air-Breathing PEMFC." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/54005298721388542023.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
96
Proton exchange membrane fuel cell (PEMFC), belonging to the field of clean power source, is widely applied in automotive applications and distributed power generation. However, PEMFC could also be great alternative in other special applications. For example, some low powered equipment with high voltage such as MAVs, robots or other small components would need a stable miniature PEMFC. Therefore, an air-breathing miniature fuel cell stack with double planar array was designed to study its characteristics performed. In this study, the rapid prototyping (RP) technology was applied to manufacture the flow field plates of the fuel cell stack. The stack with a dimension of 9cm length, 4.5cm width and 1.65cm thickness has been developed. A mono-polar assembly method is applied to 20 single cells with a 2.25cm2 electrode area in each single cell. In the stack experiment, we tested on the stack with series connection. The result shows that under the condition of passive operation in ambient temperature while the hydrogen without humidity conduction was applied, the maximum power density of the stack could reach to 80.80 mW/cm2 at 7V. This result reaches the state of the art in miniature PEMFC reported from the literature. It also revealed that the interdigitated flow field shows better performance than parallel flow field which has been used in the anode electrode. Interdigitated flow field can enhance its performance up to 30%.
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Keng-PinHuang and 黃耿彬. "Effects of Anodic Gas Conditions on Characteristics of a kW-scale Air-cooling PEMFC Stack." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/31933754988345073480.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
100
A fuel cell is one of the most promising green energy devices. Hydrogen is being used as the anodic fuel, and air is being used as the catholic oxidant in a fuel cell. While air can be obtained easily, hydrogen is much harder to produce, transport and store. Thus, hydrogen production becomes a main topic in the research of fuel cell systems. A reformer is commonly used to produce hydrogen. However, the reformate compresses a low concentration of hydrogen and a certain amount of carbon monoxide which deactivates the Pt catalyst, and therefore, using a reformer makes the power of the fuel cell system unable to be steady. In the study, a self-made kw-class 40cell PEMFC stack with reaction area of 112.85 cm2 per cell was tested. First, effects of anode and cathode stoichiometric ratio, the fuel cell stack temperature and the dew point on the stack performance was carried out. After optimal operational parameters were obtained, effects of the carbon monoxide concentration and hydrogen concentration on stack performance were performed, and the change of the carbon monoxide concentration at the anode outlet was also monitored at the same time. As can be seen in the results, the curve of voltage change with time varied with the carbon monoxide concentration, and the descending rate of voltage varied with the hydrogen concentration. On the other hand, when the mixed gas which contains carbon monoxide was flowed into the fuel cell, the cell temperature changed, too. Moreover, diluted hydrogen and carbon monoxide increased the anodic overpotential, and therefore resulted in a rivaling phenomenon between the oxidation rate of carbon monoxide and the adsorption rate of carbon monoxide on the catalyst. Thus, the stack potential fluctuated. r. In the study, air-bleeding was used to remove carbon monoxide on the catalyst surface to recover the stack performance. The results showed that flowing a small amount of air can remove most carbon monoxide adsorbed on the catalyst, and it can make the stack performance recovered and make the stack power output stable.
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Bai, Qiang, and 白強. "The Comparative Study on Performance of Air/Oxygen and Variable Load of PEMFC Stack and Its Economic Analysis." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/35764704035349442730.
Full textAbstract:
碩士元智大學
機械工程學系
105
Fuel cell is a kind of power supply with high efficiency and no pollution.Fuel cell can change fossil energy like alcohol,natural gas ,hydrogen and so on to electric energy by redox reaction.Fuel cell has a big advantage than fossil energy in high efficiency and on pollutio,so fuel cell have became a new kind of power supply to attract worldwide attention. The paper has two parts.First,now the proton exchange membrane fuel cell's cathode gas is air,but the oxygen concent in the air is only 21 ％,which may limit the maximum power of the fuel cell.The testing machine of this paper is produced by Qunyi energy limited liability company and the testing fuel cell is 5 cell detachable water-cooled fuel cell stack produced by Fubao energy limited liability company.The cathode will inject air and oxygen respectively and analyze the different power change.I will use the origin for performance curve to find the best performance curve.By collecting information about the power for oxygen production,calculate whether the use of oxygen instead of air has a net increase and then the economic caculation. Second,the paper use the software on the testing platform to simulate the operation of the coaches traveling around the island,and use the fuel cell for air and oxygen to provide power.And then observation and analysis of fuel cell performance changes and economic calculation for the fuel cell power to enhance the development of a new idea,and for fuel cell business to provide a new way of thinking.
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KUEI-CHEN, CHEN, and 陳奎辰. "A Study on the Operating Characteristics of PEMFC Stacks." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/95966014486152140247.
Full textAbstract:
碩士大葉大學
機械與自動化工程學系
98
The present research investigates the influence of humidification of reactant gas, operating temperature on the performance of an air-breathing PEM fuel cell stack. During the experiments, two methods are used to fuel the fuel cell stack: one is to supply the hydrogen by a fuel cell testing system and the other is by a metal hydride storage tank. The result shows that the supply of hydrogen affects the performance of the fuel cell stack substantially, especially the cells near the hydrogen inlet. Although supplied with humidified air, the performance of fuel cell stack decreases after one hour’s operation due to lack of hydrogen.
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Lin, Zun-Tsung, and 林存中. "Studies of Self-humidification and Stable Operation PEMFC Stacks." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/01356197091036088299.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
103
This thesis is aimed to develop a set of PEMFC that can be operated stably for long-term use. The stacks can be applied to the recharging and operation of electronic devices. Two stages are performed in present study. Firstly, the investigation of 2-cell stack stability, followed by the investigation of 8-cell stack stability and its application. The water content in the membrane is the key to maintain the performance of the fuel cell. To prevent the decay due to the lack of water content, we humidify the MEA using the cotton thread and cloth on the anode and cathode. Under the moisturizing condition, 2-cell stacks can maintain the performance stability at current density 324 mA/cm2. When cells don’t function, the water content should be held constant to avoid the detachment of MEA on account of expansion and contraction of membrane. The water content transport through membrane is done by use of cathode threads, meanwhile excessive evaporation is segregated from the atmosphere. The result shows that MEA performance can be held effectively through the proper control over water content. When applied to the 8-cell stack, similar results to 2-cell stack are yields for conserving. Nonetheless the maximal current density can only be kept under 300 mA/cm2 for stability. MEA area enlargement and the increase of formation heat are ascribed to the cause. Lastly, when compared with AC adaptor to the supply mains, 8-cell stacks consumes more time to recharge. But this disadvantage can be overcome by adjusting the connection in series/parallel or the electrode area. The application of stacks in series/parallel connection is seen to be up-and-coming for future use of electronic devices.
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Wu, Hao-Ai, and 吳浩皚. "Development of a Passive Humidification and Air-breathing PEMFC Stacks and its Improvement of Long-term Stability." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/26831043802327213888.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
104
This thesis is aimed to develop a set of passive hydrogen PEMFC that can work stably for a long time operation and to study the effect of the performance after a long period store. Finally, the developed PEMFC stacks will be applied to the recharging or operation of electronic devices. The key to maintain the performance of the fuel cell is the preservation of the water within the membrane. To prevent the fuel cell decay due to the lack of water within the membrane, we humidify the MEA by using the wetting cotton cloth in the anode and the wetting cotton thread in the cathode. The experimental results with various wetting methods are compared to that of the stack without any wetting. The result of humidification experiment shows that the stack with our wetting design can be operating continuously for more than three hours at a current of 1.05A. It depends on the quantity of water stored within anode chamber. The effects of the store ways of the fuel cell stack are also studied. The experimental results show that the stack can preserve its performance after several day store by spraying water in cathode before stack stored and then to block it from ambient during store. After the humidification and preservation tests, the 8-cell stack is applied to recharge or drive certain 3C products. The stack can be connected in series and in parallel to adjust the output voltage and current in order to provide the electronic product required. The 8-cell stack can be directly drive digital photo frame and charge smartphone. The application of stacks is seen to be up-and-coming for future use of electronic devices.
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Fang, Fu-Min, and 方富民. "Study of Gas and Water Management Systems for 5 kW PEMFC Stacks Arranged in Electrical Parallel/Cascade with Diodes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/69292956140778294252.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
101
In this study, fuel, oxidant supply and cooling systems with a microcontroller unit (MCU) were developed in a compact design to fit two 5 kW proton exchange membrane fuel cell (PEMFC) stacks (Ballard 1310). The original design of the subsystems, which had a longer pipeline and excessive control sensors, caused a large pressure drop and high power consumption. However, with an MCU, the fuel consumption and humidity can be effectively controlled within a proper purge period. Additionally, this study includes stack performances under different hydrogen recycling modes and the direct electrical coupling of two similar 5 kW stacks with diodes to obtain a higher power output. The result showed that the efficiency of the 5 kW stack is 43.46 % with a purge period of 2 minutes with hydrogen recycling and that the hydrogen utilization rate, μf, is 66.31 %. In addition, the maximum power output of the twin-coupled module (a power module with two stacks in electrical cascade/parallel arrangement) is 9.52 kW.