Tesi sul tema "Piles à combustible à membrane échangeuse de protons (PEMFC)"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Piles à combustible à membrane échangeuse de protons (PEMFC)".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
Dumercy, Laurent. "Contribution à la caractérisation thermique et fluidique d'une pile à combustible à membrane échangeuse de protons (PEMFC)". Besançon, 2004. http://www.theses.fr/2004BESA2004.
The aim of this thesis is the thermal and fluidic model of a proton exchange membrane fuel cell. The management of the internal temperature of the fuel cell affect performance, in one hand directly on the electrochemical reaction, in the other hand by determination of their internal caracteristics (hydratation of the membrane, diffusion resistance in the porous area). The modelisation is made between two axis. At first, the thermal behavior is taken into account in the global form. The fuel cell is studed as a whole with a thermal resistance network et heat sources (heat supply by electrochemical reaction, exchanges with fluids). Dirichlet boundary conditions have been used to force surface temperatures. The meshing of the network is shrink for modelizing the central cell. Specific boundary conditions are applied at this cell for quantify intterference of neighboring cells. The studied cell can be used, in this case, on many situations : adiabatic, in serial or with a external flux. In addition, anode and cathode channel have been studied with a specific model, based on the compting by finites differences of a differential equations system. Taking into account the most important physical and thermophysical quantities (pressions, flow rates, water and heat exchange coefficients), it couple internal quantities off the channel et thermal state of the overall system. The studies of the pahse change of water in the channel, his transfert beetwen the anode and the cathode and his influence on the thermal balance are studed
Mezzi, Rania. "Contrôle tolérant au vieillissement dans des systèmes pile à combustible PEMFC". Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCD031.
The objective of this work is to realize an aging-tolerant control for a proton exchange membrane fuel cell system (PEMFC). In order to achieve this goal, supervision tools, including the monitoring of critical variables, the state of health evaluation and the prediction of the future state are studied and realized. The information collected are used to adapt the system control strategy. The priority of the monitoring system developed is to ensure the energy supply required by the user, while ensuring minimal degradation of the fuel cell. The work consists on determining optimal temperature values, cathode and anode stoichiometry coefficients, and fuel cell current to provide the power required by the load, while extending the lifetime of the PEMFC. The proposed strategy avoids reversible damage and slows the aging rate of the components, while maintaining the value of the voltage in an optimal and low degrading operating range. This voltage variation range was determined by studying the degradation mechanisms of PEMFC
Krosnicki, Guillaume. "Utilisation de fullerène comme support de catalyseur pour les piles à combustible de type PEMFC". Strasbourg, 2011. http://www.theses.fr/2011STRA6224.
This work concerns the study of new fullerene-based catalysts for the cathode of fuel cell type PEMFC. The use of fullerene C60, known to be stable, as a catalyst support and the ability to bind the platinum on the fullerene can hope to improve the resistance to degradation of the active layer. As a first step, a set of type catalyst MnC60 based on platinum and / or palladium atoms bonded to C60, called metallofullerenes, were synthesized and characterized physically and chemically. In parallel, non-noble catalysts based on iron phthalocyanine deposited on fullerene have been synthesized. The performance of these catalysts were electrochemically tested on a rotating ring-disk electrode, half-cell and, for best catalysts in fuel-cell, and compared with those obtained with reference commercial catalysts on carbon black Pt/C and PtCo/C. It appears from the study that the performance of metallofullerenes depends on the stoichiometry n of MnC60 compounds and best of them exhibit performance similar or even superior to those obtained with the reference catalysts. Non-noble catalysts on fullerene can obtain performance similar to those obtained with non-noble catalysts on carbon black. In addition, an initial study of metallofullerenes aging shows these compounds have a carbon corrosion resistance similar to reference catalysts
Yakisir, Dinçer. "Development of gas diffusion layer for proton exchange membrane fuel cell, PEMFC". Master's thesis, Université Laval, 2006. http://hdl.handle.net/20.500.11794/18765.
Akrout, Alia. "Membranes hybrides nanostructurées pour application en piles à combustible". Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTS014.
The objective of this PhD work is the development of perfluorosulfonic acid (PFSA) membranes for proton exchange membrane fuel cells with high mechanical and chemical stability. The strategy used during this thesis consists of preparing composite membranes incorporating networks of polymer nanofibers (mechanical reinforcement) as well as inorganic and organic radical scavengers (chemical stabilization). To avoid the elution of the latter, nanotubular clays were used as immobilization support and incorporated directly into the PFSA membrane or into polymer nanofibers. The membranes thus prepared were characterized ex situ, then in a single fuel cell. Their gas permeability and their stability towards mechanical and chemical degradation have been evaluated by accelerated stress test
Dijoux, Étienne. "Contrôle tolérant aux défauts appliqué aux systèmes pile à combustible à membrane échangeuse de protons (pemfc)". Thesis, La Réunion, 2019. http://www.theses.fr/2019LARE0008/document.
Fuel cells (FC) are powerful systems for electricity production. They have a good efficiency and do not generate greenhouse gases. This technology involves a lot of scientific fields, which leads to the appearance of strongly inter-dependent parameters. It makes the system particularly hard to control and increase the fault’s occurrence frequency. These two issues underline the necessity to maintain the expected system performance, even in faulty condition. It is a so-called “fault tolerant control” (FTC). The present paper aims to describe the state of the art of FTC applied to the proton exchange membrane fuel cell (PEMFC). The FTC approach is composed of two parts. First, a diagnostic part allows the identification and the isolation of a fault. It requires a good a priori knowledge of all the possible faults in the system. Then, a control part, where an optimal control strategy is needed to find the best operating point or to recover the fault
Touhami, Salah. "Apparition, détection et propagation des défauts à l'anode des piles à combustible à membrane échangeuse de protons". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0151.
Defects known to shorten the lifetime of polymer electrolyte membrane fuel cells (PEMFC) can appear on different membrane electrode assembly (MEA) components and under different forms due to manufacturing processes or operational aging of the fuel cell. This work concerns the occurrence, detection, and propagation of defects in PEMFC MEA, and more specifically at the anode. To this end, an accelerated stress test (AST) combining potential and humidity cycles -induced by load variations-, and open-circuit hold is applied to standard MEA, and to MEA with initial defects. Those customized MEA were intentionally prepared with a lack of active layer at the anode, the defect being located either near the hydrogen inlet or near the hydrogen outlet. Periodic electrochemical characterizations were carried out using a segmented instrumented linear cell, allowing to monitor the cell performance through the currents, electrode potentials, and local impedance, as well as the evolution of the electrochemical active surface (ECSA) at the anode and cathode during the ageing test, with a spatial resolution along the channels. An electrochemical impedance spectroscopy study was conducted jointly, using equivalent electrical circuits, and focusing on the detection of the anodic contribution to the global impedance of the cell. Results showed an accelerated degradation of the MEA and the first evidence of defect propagation, in terms of loss of ECSA at the anode. This propagation occurred in the direction of the hydrogen flow. The ECSA at the cathode also appeared to be impacted, although apparently homogeneously. Significant membrane thinning was also observed in the defective segments, with probable propagation to adjacent segments, but over a longer time period
Rambaud, Frédéric. "Elaboration de matériaux hybrides par procédé sol-gel pour application pile à combustible PEMFC". Paris 6, 2011. http://www.theses.fr/2011PA066046.
Hybrid membranes composed of a non-conductive protonic organic polymer with an inorganic conductive particles were produced for a PEMFC application with the objective of increasing the operating temperature. In order to lengthen the life expectancy of the electrodes and to improve its effectiveness, we need to increase the operating temperature. The original concept of this study employed the use of an anisotrope functionalized inorganic mesoporous componant dispersed into an organic phase. Silica is a material known for its hygroscopic characteristics. Additionally, silica has an easily modifiable surface, which brings interesting properties to electrolyte application. The first step of this study consisted of morphological control of the hybrid charge with a shape factor higher than 8 and with a large specific surface structure. The obtained nanofibers induced the protonic conduction into the polymer by forming preferential conduction paths of protons through the membrane. The movement of these cations was performed by incorporating sulfonic groups onto the porous surface of the fibers. The protonic motion was dependent on the number of active sites. A post-hybridation was necessary to increase the performance of the hybrid nanofibers. Two manners of post-incorporation and processes were studied and improved, which gave a protonic conduction equivalent to Nafion®
Ferrandez, Anne-Claire. "Synthèse et caractérisation des nouvelles architectures catalytiques pour une application en pile à combustible du type PEMFC". Poitiers, 2011. http://nuxeo.edel.univ-poitiers.fr/nuxeo/site/esupversions/1cb2c4a4-6d5f-47d5-b0a0-5d40f245abd4.
This thesis is within the scope of new catalytic layers development for proton exchange membrane fuel cell (PEMFC) based on the transposition of the phenomenology of the three-phase boundary at the molecular scale. The fieldwork concerns the working out of hybrid organic/inorganic catalyst by grafting proton conducting polymers (PSS). Both methods have been developed to introduce the polymer on the platinum nanoparticles. The first method consists of using the "grafting from" technique and controlled radical polymerization (Atom Transfer Radical Polymerization). The second grafting method used is the "grafting onto" technique. It consists first in synthesizing the polymer and second in grafting by reaction of the functions of the latter with platinum nanoparticles. Modifications of synthesis parameters allowed constituting a collection of objects showing a wide range of grafting density. Electrochemical characterizations have brought numerous information on the structure, activity and selectivity of hybrid catalytic complex
Sellin, Rémy. "Dégradation de catalyseurs Pt-C sous des conditions mimant celles d'une PEMFC en fonctionnement". Poitiers, 2009. http://theses.edel.univ-poitiers.fr/theses/2009/Sellin-Remy/2009-Sellin-Remy-These.pdf.
Fuel cell Pt/C catalysts were prepared via different colloidal methods. TGA, TGAMS, TEM and XRD studies from 323 to 573 K were carried out under oxidative and reductive atmospheres to mimic fuel cell anode and cathode working conditions and to accelerate ageing process. Under air flow, little aggregation of platinum is observed, but no fusion and increase of Lv. This is explained by the presence of oxygen species on the platinum surface. Under reductive atmosphere (H2 3%/He), aggregation and increase of the mean crystallite size are observed. Two kinetics of grain growth process seem to exist. Moreover, the carbon support undergoes degradation by combustion under air and reforming under reductive atmosphere. The effect of thermal treatment under controlled atmospheres on the electrochemical active surface area and on the electrocatalytic activity towards oxygen reduction reaction and CO oxidation of the Pt/C catalyst were evaluated
Li, Yongli. "Synthèse et propriétés de transport de membranes constituées d’alliages de polymères pour piles à combustible de type PEMFC". Caen, 2009. http://www.theses.fr/2009CAEN2008.
New proton exchange membranes were prepared from blends of sulfonated Polyetheretherketone (PEEK) and sulfonated Polyethersulfone cardo (PESc). The blended membranes are obtained by casting the collodion in a Petri dish, then the solvent was evaporated and finally they are treated in a solution of concentrated hydrochloric acid to get the acidic form of the proton exchange material. Seven membranes are prepared by blending the two pure polymers with different mass fraction. They are characterized by measuring the ion exchange capacity, the ionic conductivity, the water swelling, the water vapor sorption and permeation at 30 °C. The optimized membrane for the future application to PEMFC has the following wt% composition: 40 % SPEEK and 60 % SPESc. This membrane has an ion exchange capacity of 1. 32 meq/g of dry polymer, a conductivity of 0. 090 W-1. Cm-1 at 30 °C in a 0. 2 M HCl aqueous solution, a water swelling ratio of 35% at 30°C. A theoretical study, based on the generalized Nernst-Planck diffusion equation in the dusty gas model was developed to predict the properties of water vapour diffusion and the conductivity of all the blended membranes from the properties of the two pure polymers
Ilie, Valentina Alina. "Contribution à l'optimisation des AMEs et au développement des métrologies spécifiques pour les piles à combustible PEMFC et SAMFC". Poitiers, 2010. http://nuxeo.edel.univ-poitiers.fr/nuxeo/site/esupversions/b6c1771f-b6ea-470a-8e47-6083123f84ad.
This thesis point to the optimization of the PEMFC MEAs made by hot pressing, the optimization of SAMFC working parameters and performances, and the development of specific metrologies for the water and heat management inside the AMEs core. This research is part of the “CHAMEAU” project and ANR PAN-H program and of the “AMELI-0Pt” project of CNRS “Energy” program. First objective concerns the search for the optimal parameters (temperature, pressure, and pressing time) of the MEAs manufacturing by hot pressing. The results obtained through designed experimental make known temperature as the most influential factor on the fuel cell electrical performances. The electrical power density increases with the temperature range 100°C-115°C and decreases sharply after. This critical value is seemed to be associated to the Nafion® glass temperature. Secondly, we focus on the development of the glycerol SAMFC fuel cells. Studies concerning the optimization of the operating conditions have identified the important parameters for improving the SAMFC performances and help to realize a test protocol. Catalysts less/free platinium have revealed a visible increase in electrical performance compared to the pure Pt/C catalysts and plasma membranes shown the possibility to triple the SAMFCs electrical performance. The third target, is the development of specific metrologies for the temperature measurements at the interface between the membrane and the active layer. MEA embedded thermo-resitive sensors have shown the feasibility and the utility of the real-time monitoring temperature of the active layer
Bouatia, Eloumami Souhail. "Développement de matériaux électriquement conducteurs pour les plaques bipolaires de piles à combustibles à membrane échangeuse de protons, PEMFC". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25545/25545.pdf.
Labbe, Fabien. "Carbones revêtus de dioxyde d’étain comme supports cathodiques plus durables dans les piles à combustible à membrane échangeuse de protons (PEMFCs)". Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM006/document.
The proton exchange membrane fuel cell’s lifespan is insufficient because of the degradation of carbon used as cathodic catalyst supports. In order to reduce this degradation, a thin tin dioxide coating is synthesized on the surface of different carbonaceous materials (nanotubes, carbon blacks and aerogel). The aim is to combine the morphology and the electric conductivity of the carbon with the thermodynamic stability of the tin dioxide. Carbonaceous materials with different intrinsic properties are chosen for this study to test a wide range of textures and structures. Experimental studies were carried out in order to synthesize a thin, homogeneous and covering tin dioxide coating. The major influences of the texture and structure of carbonaceous materials but also the influence of the pH value on the quantity and quality of the coating are highlighted. It turns out that the mechanism of formation of tin dioxide depends on this pH value. Thanks to the improvement of the interactions between the carbon surface and the reactive species, it was possible, in some cases, to reduce drastically the quantity of precursor. Platinum nanoparticles deposition performed on various materials (raw or coated carbon aerogel) highlights a different platinum behavior. In fact, on the tin dioxide surface, nanoparticles tend to agglomerate together instead of making a homogeneous dispersion. Then, the initial performances and the durability of electrocatalysts tested with two accelerated stress tests (load protocol or start/stop protocol) are evaluated, spotlighting mitigate results
Silva, Sanchez Rosa Elvira. "Contribution au pronostic de durée de vie des systèmes piles à combustible PEMFC". Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2005/document.
This thesis work aims to provide solutions for the limited lifetime of Proton Exchange Membrane Fuel Cell Systems (PEM-FCS) based on two complementary disciplines:A first approach consists in increasing the lifetime of the PEM-FCS by designing and implementing a Prognostics & Health Management (PHM) architecture. The PEM-FCS are essentially multi-physical systems (electrical, fluid, electrochemical, thermal, mechanical, etc.) and multi-scale (time and space), thus its behaviors are hardly understandable. The nonlinear nature of phenomena, the reversibility or not of degradations and the interactions between components makes it quite difficult to have a failure modeling stage. Moreover, the lack of homogeneity (actual) in the manufacturing process makes it difficult for statistical characterization of their behavior. The deployment of a PHM solution would indeed anticipate and avoid failures, assess the state of health, estimate the Remaining Useful Lifetime (RUL) of the system and finally consider control actions (control and/or maintenance) to ensure operation continuity.A second approach proposes to use a passive hybridization of the PEMFC with Ultra Capacitors (UC) to operate the fuel cell closer to its optimum operating conditions and thereby minimize the impact of aging. The UC appear as an additional source to the PEMFC due to their high power density, their capacity to charge/discharge rapidly, their reversibility and their long life. If we take the example of fuel cell hybrid electrical vehicles, the association between a PEMFC and UC can be performed using a hybrid of active or passive type system. The overall behavior of the system depends on both, the choice of the architecture and the positioning of these elements in connection with the electric charge. Today, research in this area focuses mainly on energy management between the sources and embedded storage and the definition and optimization of a power electronic interface designated to adjust the flow of energy between them. However, the presence of power converters increases the source of faults and failures (failure of the switches of the power converter and the impact of high frequency current oscillations on the aging of the PEMFC), and also increases the energy losses of the entire system (even if the performance of the power converter is high, it nevertheless degrades the overall system)
Lamibrac, Adrien. "Étude des dégradations dans les piles à combustible PEMFC pendant les phases de démarrage/arrêt". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0117/document.
This works contributes to the identification of the various degradation mechanisms in Polymer Electrolyte Membrane Fuel Cell during start-up and shut-down operations. Single start-ups and shut-downs are first analysed using a cell with segmented cathode current collectors. Thus, internal currents which occur during these operations can be measured. Carbon dioxide measured in the cathode exhaust gas reveals that they result partially from carbon oxidation. Another contribution is the reversible or non reversible redox reactions involving platinum. The heterogeneity of the non reversible platinum oxidation between the inlet and outlet of the cathode is evidenced by the in-situ monitoring of the Electrochemical Surface Area during long-term start-up and shut-down aging protocols. Post-mortem analysis reveals another level of heterogeneity, which concerns also carbon oxidation, between land and channel. From these experiments, it appears also that degradations are more important when gases are injected with a low velocity in the anode compartment and when air is used instead of nitrogen to flush the anode compartment during shut-down. The influence of the MEA characteristics on the extent of the degradation observed during these aging protocols is also analyzed. High platinum loading in the anode and high surface carbon electrodes accelerate the drop of the electrical performances, while increasing the cathode platinum loading limits their decay. Finally, numerical simulations of start-ups complete the experimental results. Reversible platinum oxidation was found to be one of the main contribution to the internal currents
Campagne, Benjamin. "Nouveaux copolymères fluorés porteurs de fonctions azole (imidazole, benzimidazole ou triazole) pour membranes pour piles à combustible (PEMFC) fonctionnant en conditions quasi-anhydres". Thesis, Montpellier, Ecole nationale supérieure de chimie, 2013. http://www.theses.fr/2013ENCM0006.
This work concerns the syntheses and characterizations of new proton exchange polymer membranes containing N-heterocyclic compounds for PEMFC working under low relative humidity (HR < 25 %) and temperatures up to 200 °C for automotive applications. Three new partially fluorinated copolymers bearing different azole compounds (imidazole, benzimidazole or 1H-1,2,4-triazole) as pendant groups have been synthesized and characterized. Then, they have been used to synthesize blend polymer membranes with s-PEEK (20 µm < thickness < 100 µm) that showed thermal stabilities up to 210 °C. These new families of membranes have been compared and highest proton conductivity values have been observed for 1H-1,2,4-triazole containing membranes (σ = 7,0 mS.cm-1, 140 °C, HR < 25 %). Mechanical properties and oxidative stability of these membranes have been assessed and showed similar values than main commercially available membranes. To improve membranes structuration, pseudo semi-interpenetrating polymer networks have been synthesized. Thus, original cross-linkable terpolymers bearing 1H-1,2,4-triazole and cyclocabonate functions as pendant groups have been synthesized and blended with s-PEEK as linear polymer to synthesize new polymers membranes (20 µm < thickness < 60 µm). Cross-linking has been carried from the cyclocarbonate/diamine reaction to get pseudo semi-interpenetrated polymer networks. Finally, both pseudo semi-interpenetrated polymer networks and uncross-linked membranes were doped by immersion in phosphoric acid solution to increase proton conductivity of these materials. Single cell fuel cell tests have been carried out and showed good performances. High temperatures (140 – 180 °C) proton conductivity values of these doped membranes have been estimated from extrapolation curves and reached up to 210 and 250 mS.cm-1, at 180 and 200 °C, HR < 25 %, respectively (extrapolated values). Proton conductivity values should be assessed at these targeted temperatures (140 to 200 °C)
Athmouni, Nafaa. "Développement et caractérisation de nouveaux nanocomposites polymères électriquement conductueurs pour plaques bipolaires de piles à combustible à membrane échangeuse de protons, PEMFC". Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26861.
Faced to the declining of energy resources and the increase of energy pollution, many researches are focused on the production of clean and sustainable energy in order to reduce the use of fossil sources energy since they are the main source of greenhouse gases production. The Proton Exchange Membrane Fuel Cell (PEMFC) is a technology that is becoming increasingly important for clean and sustainable energy production. The PEMFC is an electrochemical device that operates according to the principle of inverse electrolysis of water. A PEMFC converts the chemical reaction between hydrogen and oxygen (or air) into electrical power, heat and water, while releasing only water steam into the atmosphere. A PEMFC consists of a bended multilayer Electrode-Membrane-Electrode (EME), where the membrane is a solid polymer electrolyte separating the anode and the cathode. This set is built between two bipolar plates used for collecting the electrical current and distributing the gas (hydrogen or oxygen) through gas flow paths etched on each face of the bipolar plates. Most of the recent research focused on the improvement of PEMFC performances, their durability and the reduction of their production cost. A lot of work was done on the development and characterization of the different elements of PEMFCs, including the bipolar plates, considered as one of the most expensive and most massive parts. The design of the bipolar plates must consider several parameters. They should combine good mechanical strength, good chemical and thermal stability, sufficient electrical conductivity and good ability to remove heat generated in the heart of the cell. Metal bipolar plates are penalized by their corrosion resistance, which causes a reduction of the cell life. Those obtained from graphite are brittle and their manufacturing cost is high (mainly due to channels machining cost). Therefore, much research is focused on the development of new concepts of bipolar plates in order to replace metals and graphite by new polymer based composites. The latter appear to be more attractive because of their good processing ability that could help reducing the production cost of PEMFCs. However, much more research has to be done on the improvement of their electrical and mechanical properties, which is the main objective of the present thesis in which we propose: i) To develop by twin-screw extrusion process an optimized polymer nanocomposite material in which conductive solid additives are incorporated, including carbon nanotubes. ii) Fabricate a bipolar plate prototype from theses optimized nanocomposites by using the compression molding process under controlled cooling. In this project, two thermoplastic polymers have been used as the matrix: polyvinylidene fluoride (PVDF) and polyethylene terephthalate (PET). Three electrically conductive fillers were also used: carbon black, graphite and carbon nanotubes. Various combinations of these conductive additives were also studied in order to develop optimized nanocomposite formulations. Through-plane electrical conductivity of the developed nanocomposites as well as their mechanical properties have been carefully characterized. The obtained results showed that not only the combination of the conductive additives influences the nanocomposites through-plane conductivity and their mechanical properties, but also the distribution of these solid additives (which in turn depends on their nature, their size and their surface properties) helped to improve these properties. It has been observed that the surface treatment of the carbon nanotubes used in this study helped to increase both through-plane conductivity and mechanical strength of the developed bipolar plate prototypes. It was also observed that the crystallinity generated during bipolar plate cooling inside the compression mold as well as the crystallization rate play an important role in the optimization of the through-plane electrical conductivity and mechanical properties.
Cognard, Gwenn. "Electrocatalyseurs à base d’oxydes métalliques poreux pour pile à combustible à membrane échangeuse de protons". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI007.
Conventional electrocatalysts used in proton exchange membrane fuel cells (PEMFC) are composed of platinum nanoparticles supported on high specific surface area carbon blacks. At the cathode side of the PEMFC, where the oxygen reduction reaction (ORR) occurs, the electrochemical potential can reach high values - especially during startup-shutdown operating conditions - resulting in irreversible degradation of the carbon support. A “material” solution consists of replacing the carbon with supports based on metal oxides. The latter have to be resistant to electrochemical corrosion, be electronic conductor and have a porous and nano-architectural structure (for the transport of reagents and products and the homogeneous distribution of the ionomer and platinum nanoparticles).In this work, we have developed and characterized electrocatalysts composed of platinum (Pt) nanoparticles based on tin dioxide (SnO2) and titanium dioxide (TiO2) with optimized textural (aerogel, nanofibres or loosetubes morphologies) and electron-conduction properties (doped with niobium Nb or antimony Sb). The best electrocatalytic properties are reached for an antimony-doped SnO2 aerogel support, denoted ATO. The Pt/ATO electrocatalyst has especially a higher specific activity for the ORR than a Pt/carbon Vulcan® electrocatalyst, synthesized in the same conditions, suggesting beneficial interactions between the Pt nanoparticles and the metal oxide support (Strong Metal Support Interactions SMSI).Durability tests simulating automotive operating conditions of a PEMFC were carried out in liquid electrolyte at 57 °C on these two electrocatalysts by cycling between 0.60 and 1.00 V vs the reversible hydrogen electrode (RHE) or between 1.00 and 1.50 V vs RHE. The Pt/ATO electrocatalyst has an increased stability compared to the reference Pt/carbon Vulcan® electrocatalyst. However, new degradation mechanisms were highlighted in this study: first, the doping element (Sb) is progressively dissolved during electrochemical ageing, which implies a loss of electronic conductivity. This loss is partly due to incursions at low potential, including during electrochemical characterizations. Moreover, between 5,000 and 10,000 cycles of the accelerated stress tests (between 0.60 and 1.00 V vs RHE or between 1.00 and 1.50 V vs RHE at 57 °C), the support loses its porous structure and forms a poorly conductive amorphous film
Zhao, Zuzhen. "Détermination des mécanismes de dégradation d'électrodes modèles de pile à combustible à membrane échangeuse de protons". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00764891.
Passot, Sylvain. "Etude expérimentale et par modélisation de l'impact d'impuretés de l'hydrogène sur le fonctionnement des piles à combustible à membrane échangeuse de protons (PEMFC)". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00813426.
Mrad, Christine. "Caractérisation ex-situ par RMN et IRM des transferts d'eau à l'interface membrane/électrode dans les piles à combustible PEMFC". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0358.
In the context of sustainable energy transition, Proton Exchange Membrane Fuel Cells (PEMFC) are considered promising alternatives to conventional engines. They offer efficient conversion of hydrogen into electricity without emitting pollutants. However, for the widespread deployment of these systems, it is essential to reduce their cost and improve their durability. This is the focus of the European project « ALPE: Advanced Low-Platinum hierarchical Electrocatalysts for low-T fuel cells », in which this thesis is situated. The project aims to reduce the cost of PEMFCs by decreasing the amount of platinum (Pt), catalyst used in their electrodes, targeting a reduction of 1.5 to 2 times compared to the state of the art in 2019. The operation of PEMFCs relies essentially on the electrochemical reactions occurring on the Pt catalytic sites, and proton transport is closely linked to the hydration state of the electrolyte membrane (water serving as a vector for protons). Therefore, the objective of this thesis is to study the impact of reducing the amount of Pt on the water transport phenomena across the membrane-electrode/air interfaces. In order to achieve this goal, experimental devices and methodologies for analyzing the membrane/electrode interface through spectroscopy and magnetic resonance imaging (NMR/MRI) have been developed. Initially, the study focuses on the examination of a single Nafion® membrane (N1110). An in-situ analysis that allows visualization of the impact of the membrane's hygrothermal history on the properties of water is presented. Furthermore, experiments under different relative humidity conditions on each side of the membrane demonstrate the capability of our approach to quantify interfacial resistances of water transfer while decoupling them from diffusive effects within the membrane. Additionally, a 1D steady-state model of the diffusion of water across the thickness of the membrane allows to determine the evolution of the mutual water diffusion coefficient. To complement our analysis, a partial acquisition measurement sequence has been designed to minimize the acquisition time of water profiles within the membrane, paving the way for a transient study. Finally, a comparison of interfacial resistances between a single membrane and a membrane with electrode(s) provides insights into the impact of adding an electrode deposit and varying the platinum loading on water transport phenomena. The results highlight that in transient conditions, there are no significant differences between a single Nafion® membrane and a membrane/electrode assembly (with one or two electrodes). However, it appears that the presence of the electrode and the amount of platinum seem to influence the evolution of interfacial resistances depending on the relative humidity (RH) of the air supplied to the sample
Woo, Sahng Hyuck. "Membranes composites acide perfluorosulfonique (PFSA)/argile pour un fonctionnement à faible humidité relative et haute température des piles à combustible à membrane échangeuse de protons (PEMFC)". Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEM033.
This thesis introduces novel electrolyte membranes which can be operated at low relative humidity (below 50%) and intermediate temperature, i.e., 90℃. More specifically, the thesis takes benefit from hygroscopicity of microfibrous SEP (sepiolite) and tubular HNT (halloysite). Changes in Nafion membrane properties with blending time were studied. Moreover, these nanoclays are functionalized and pretreated to make them proton conductive and to improve their compatibility with short-side-chain PFSA (perfluorosulfonic acid) composite membranes based on Aquivion. To begin with, functionalized and pretreated clay nanoparticles are characterized prior to incorporation in polymer matrix: ATR-FTIR (attenuated total reflection-fourier transform infrared spectroscopy), Py-GC/MS (pyrolysis gas chromatography mass spectrometry), and TGA (thermogravimetric analysis). Composites membranes have them been prepared and characterized for proton conductivity, water uptake, swelling, thermo-mechanical strength and chemical stability. The dispersion state of SEP and HNT inside polymer phase was observed using SEM/EDS (field emission scanning electron microscopy/Energy dispersive X-ray spectroscopy). The properties of pretreated nanoclays are characterized using XRD (X-ray diffraction) and EDS. Chemical stability regarding radical attack against composite membranes is clarified using Ion meter through fluoride ion (F-) analysis. Proton conductivity of composite membranes is also measured under condition of different relative humidity and temperature. Following this, it is demonstrated by DMA (dynamic mechanical analysis) results that the particular elongated morphology of SEPs and HNTs participates to improving mechanical property of the composite membranes with decreased swelling ratio. MEAs (membrane electrode assembly) performance are evaluated to understand the advantage of the presence of nanoclays in the composite membranes regarding the relative humidity of the feeding gas, the operating temperature of the cell, and the hydrogen crossover. Detailed abstracts including main results were provided at the beginning of each chapter
Ozouf, Guillaume. "Electrodes à base d’aérogels de SnO2, résistantes à la corrosion pour la réduction de l’oxygène dans les piles à combustible à membrane échangeuse de protons (PEMFC)". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM060/document.
In order to tackle the problem of low durability, tin dioxide aerogels were studied to replace carbon black as a catalyst support in proton exchange membrane fuel cells (PEMFCs). SnO2 is a well-known n-type semi-conductor whose electronic conductivity can be improved by doping with hypervalent cations such as Nb5+, Ta5+ or Sb5+. In addition, as a catalyst support, this material has to develop a high specific surface area with adequate mesoporous morphology to allow both good dispersion and activity of the catalyst (Pt). To this end, our objective was to develop doped SnO2 aerogels. In this study, SnO2 based-aerogels were successfully synthesized following an acid-catalyzed sol–gel route starting with metal alkoxides as precursors. Our materials have shown a very interesting airy morphology with among other a reasonable specific surface area (80–90 m2/g). Moreover, all Sb-doped aerogels exhibited significant improvement in electronic conductivity and reach a value of around 0.12 S/cm. Platinum nanoparticles were then deposed on the Sb doped SnO2 aerogel surface using three different methods. The method based on chemical reduction using a polyol route provided the best result in term of mass catalytic activity measured by RDE (Is = 32 mA/mgPt). This value is even higher than that of the reference electrocatalyst TEC10E40E (Is = 27 mA/mgPt). Sb doped SnO2 aerogel based MEAs have exhibited a very good durability at high potentials
Durst, Julien. "Etude du vieillissement des assemblages membrane-électrodes pour piles à combustible basse température". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00923165.
Gaumont, Thomas. "Résistance protonique d’électrodes de piles à combustible à membrane (PEMFC) : effets de l’humidité et des dégradations". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0002/document.
This work focuses on the development of electrochemical impedance spectroscopy (EIS) methods to measure the protonic resistance of PEMFC active layers. Experimental spectra of a cathode fed with nitrogen are fitted to a volumetric electrode impedance model to yield the protonic resistance of the electrode and that of the membrane in controlled humidity conditions. In addition, EIS measurements are performed on a cathode fed with oxygen, delivering current and producing water. The protonic resistances of the membrane and of the electrode are obtained in several conditions of gas stoichiometry and of current density. The effective humidity within the membrane and within the electrode is estimated using the calibration obtained in controlled humidity conditions. Thus, the monitoring of a MEA self humidification is achieved with spatial resolution using a segmented cell designed in our lab. The effective humidity is higher in the catalyst layer than in the membrane. A second part of this work is dedicated to the catalyst layer degradations. Accelerated stress tests consisting in a membrane chemical degradation protocol, a carbon degradation protocol, a start-up protocol and a dry operation regime are performed. A compaction of the electrode due to carbon corrosion is detected during start-up protocols. A strong chemical attack of the ionomer has been observed within the membrane, close to the cathode side. However, no degradation of the ionomer within the cathode has been measured
Wu, Yiming. "Long term performance prediction of proton exchange membrane fuel cells using machine learning method". Thesis, Belfort-Montbéliard, 2016. http://www.theses.fr/2016BELF0308/document.
The environmental issues, especially the global warming due to greenhouse effect, has become more and morecritical in recent decades. As one potential candidate among different alternative "green energy" solutions forsustainable development, the Proton Exchange Membrane Fuel Cell (PEMFC) has been received extensiveresearch attention since many years for energy and transportation applications. The PEMFC stacks, can produceelectricity directly from electrochemical reaction between hydrogen and oxygen in the air, with the only by-productsof water and heat. If the hydrogen is produced from renewable energy sources, this energy conversion is 100% ecofriendly.However, the relatively short lifespan of PEMFCs operating under non-steady-state conditions (for vehicles forexample) impedes its massive use. The accurate prediction of their aging mechanisms can thus help to designproper maintenance patterns of PEMFCs by providing foreseeable performance degradation information. In addition,the prediction could also help to avoid or mitigate the unwanted degradation of PEMFC systems during operation.This thesis proposes a novel data driven approach to predict the performance degradation of the PEMFC using animproved relevance vector machine method.Firstly, the theoretical description of the PEMFC during operation will be presented followed by an extensivelydetailed illustration on impacts of operational conditions on PEMFC performance, along with the degradationmechanisms on each component of PEMFC. Moreover, different approaches of PEMFC performance prediction inthe literature will also be briefly introduced.Further, a performance prediction method using an improved Relevance Vector Machine (RVM) would be proposedand demonstrated. The prediction results based on different training zones from historical data will also bediscussed and compared with the prediction results using conventional Support Vector Machine (SVM).Moreover, a self-adaptive kernel RVM prediction method will be introduced. At the meantime, the design matrix ofthe RVM training will also be modified in order to acquire higher precision during prediction. The prediction resultswill be illustrated and discussed thoroughly in the end.In summary, this dissertation mainly discusses the analysis of the PEMFC performance prediction using advancedmachine learning methods
Asset, Tristan. "Particules creuses peu expensives, durables et actives pour la réduction de l'oxygène dans le cadre d'une application en pile à combustible à membrane échangeuse de protons". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI037/document.
This thesis investigates the mechanisms driving the formation, the en-hanced activity for the oxygen reduction reaction (ORR) and the dura-bility of porous hollow PtM/C nanoparticles (NPs) for proton exchange membrane fuel cell (PEMFC) applications. The formation and growth of the NPs, synthesized by a ‘one-pot’ process, were discussed in the light of microscopic, in operando X-ray and electronic measurements, unveiling the different intermediate steps of the synthesis. The synthe-sis process was extended to different non-noble metals (M = Ni, Co, Cu, Zn and Fe) and to different carbon supports. The enhanced activity for the ORR resulted from (i) the contraction of the lattice parameter by the non-noble metal (the final NPs contains ca. 15 – 20 at. % of M), (ii) the open porosity and (iii) the density of structural defects at the surface of the NPs, rationalized by COads stripping measurments and Rietveld analysis. The non-noble metal was found to segregate faster than the structural defects during the accelerated stress tests
Abbou, Sofyane. "Phénomènes locaux instationnaires dans les piles à combustible à membrane (PEMFC) fonctionnant en mode bouché (dead-end)". Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0208/document.
This work investigates the local transient phenomena occurring in proton exchange membrane fuel cells (PEMFC) operated with a dead-ended anode. The dead-end mode consists in closing the anode outlet, which leads eventually to local hydrogen starvation due to the excessive accumulation of liquid water and nitrogen (because of membrane crossover) in the anode compartment. Such fuel-starvation events may remain undetected but can entail a significant rise of the anode (and thus cathode) potentials and accelerate carbon corrosion and catalyst degradation. To access local information, we developed an innovative segmented linear cell with reference electrodes along the gas channels. By simultaneously monitoring the local potentials and current densities during operation, we assessed the impact of fuel starvation and observed strong local cathode potential excursions close to the anode outlet. Aging protocols based on fuel cell operation with a dead-ended anode (longer than in real use condition) showed non-uniform cathode ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area: the damage was more severe in the regions suffering the longest from fuel starvation. Parametric studies completed by numerical simulations showed that the fuel starvation is mainly governed by liquid water accumulation in the anode channels, as well as nitrogen crossover through the membrane. As a consequence, water management impacts significantly the cathode potential variations and thus the resulting electrode degradation. Starting from this founding, we propose strategies to improve fuel cell lifetime
Linares, Lamus Rafael Antonio. "Alimentation d’une bobine supraconductrice par une pile à combustible à hydrogène et conception d'un aimant vectoriel de 3 T". Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0249/document.
The fuel cell (FC) converts the chemical energy of the reactants into direct electrical energy, heat and water. The FC is generally used around an operating point (or area) corresponding to a maximum of electric power. The direct current produced by the redox reaction is proportional to the active surface of the single cell and its voltage, which is approximately 0.6 V at the nominal operating point, can be increase by connecting several cells in series (constituting a stack). Due to its low DC voltage amplitude, its use in electrical systems requires the use of power converters. In this work, we have been interested taking benefit of such DC low voltage power source and more precisely the use of the FC as a current source controllable by the one of the reactant flow rates. The expertise of GREEN laboratory in the field of superconductors has naturally led us to an innovative application, namely to substitute the power supplies dedicated to the superconducting devices by a FC. A first promising test conducted on a 4 mH superconducting coil highlighted the full potential of such an application and encouraged us to extend the study to highly inductive superconducting coils where the energies involved are more important. This requires to carefully design the test bench with a protection system for the FC as well as operating conditions. To this end, a FC model supplying a superconducting coil has been developed and tested experimentally. At the same time, we have focused on the supply part of the superconducting coil by designing an innovative superconducting device, commonly called a three-axis vector magnet. This system can be used as a load for a fuel cell, but also, and above all, as a tool for the characterization of superconducting samples. This vector magnet allows to orient a magnetic field of several tesla in the three space directions, with a uniformity of more than 95 % in a 100 mm sphere of diameter. This design allowed us to realize the windings supporting structure and to choose a superconducting wire. The complete system has to cost less than 50 k€, including the cryostat, we have finally choose a superconducting wire with low critical temperature, cooled by liquid helium
Linares, Lamus Rafael Antonio. "Alimentation d’une bobine supraconductrice par une pile à combustible à hydrogène et conception d'un aimant vectoriel de 3 T". Electronic Thesis or Diss., Université de Lorraine, 2017. http://www.theses.fr/2017LORR0249.
The fuel cell (FC) converts the chemical energy of the reactants into direct electrical energy, heat and water. The FC is generally used around an operating point (or area) corresponding to a maximum of electric power. The direct current produced by the redox reaction is proportional to the active surface of the single cell and its voltage, which is approximately 0.6 V at the nominal operating point, can be increase by connecting several cells in series (constituting a stack). Due to its low DC voltage amplitude, its use in electrical systems requires the use of power converters. In this work, we have been interested taking benefit of such DC low voltage power source and more precisely the use of the FC as a current source controllable by the one of the reactant flow rates. The expertise of GREEN laboratory in the field of superconductors has naturally led us to an innovative application, namely to substitute the power supplies dedicated to the superconducting devices by a FC. A first promising test conducted on a 4 mH superconducting coil highlighted the full potential of such an application and encouraged us to extend the study to highly inductive superconducting coils where the energies involved are more important. This requires to carefully design the test bench with a protection system for the FC as well as operating conditions. To this end, a FC model supplying a superconducting coil has been developed and tested experimentally. At the same time, we have focused on the supply part of the superconducting coil by designing an innovative superconducting device, commonly called a three-axis vector magnet. This system can be used as a load for a fuel cell, but also, and above all, as a tool for the characterization of superconducting samples. This vector magnet allows to orient a magnetic field of several tesla in the three space directions, with a uniformity of more than 95 % in a 100 mm sphere of diameter. This design allowed us to realize the windings supporting structure and to choose a superconducting wire. The complete system has to cost less than 50 k€, including the cryostat, we have finally choose a superconducting wire with low critical temperature, cooled by liquid helium
Salah, Abdelkrim. "Simulation et contrôle de l'aspect thermique d'une pile à combustible PEMFC". Besançon, 2008. http://www.theses.fr/2008BESA2062.
This thesis deals with contribution to thermal problems of PEM Fuel Cell. In fact, since the chemical conversion of energy stored within the fuel cell is accompanied by the production of an important thermal energy (50 %), it is most important to understand the thermal behavior of fuel cell. Majority of models involves complex systems of heat differential equations. In addition, PEMFC presents a heterogeneous system and thermal coupling of conduction-convection involves complex differential equations, and their solution can not be done within a reasonable amount of time by sequential program. In the first part of this work, seeking reliable and simple method for study of thermal behavior phenomena, we have developed the nodal approach that result from a formal analogy between analogical circuits and their counterpart’s phenomena. In this approach, we can represent the two phenomena of conduction-convection without any coupling of with another approach of representation. It will be shown in this thesis that this model presents high scalability and parallel processing characteristics that make it suitable for simulation on parallel machines or a network of workstations. In the second part of this work, we have interested to the control of the temperature of fuel cell. The model inspired by the nodal approach that we have developed is in the bilinear form. We propose a result on feedback stabilization of thermal behavior of PEM Fuel Cell
Cellier, Julien. "Etude et caractérisations de membranes nanocomposites hybrides pour pile à combustible du type PEMFC". Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4001/document.
The proton conductive membrane is an essential part of the operation of PEMFC. This document presents the development of a non-perfluorinated membrane based on a hybrid nanocomposite technology likely to be produced at low cost. This membrane is composed of a poly(VDF-co-HFP) matrix in which are dispersed poly(styrene sulphonic acid) (PSSA) functionalized silica nanoparticles. This work focuses on the study of the implementation of the membrane to obtain a homogeneous and dense membrane with good physicochemical and electrochemical characteristics. Fuel cell performances after running at 60 °C are extremely satisfactory with a gain, compared to Nafion NRE211, of 40% for the power density at 0.7 V. However, the durability studies showed an elution phenomenon of the functionalized silica particles which results in a high voltage decline. Different membrane modification strategies have been proposed to improve the stability of the membrane. The most interesting involve modifying the morphology of the matrix (more rigid grades of PVDF or poly(VDF-co-HFP) crosslinking by radiation) to better confine the particles or grafting functionalized silica to the matrix. This last strategy leads to a threefold decrease of the swelling and 2.5 factor of the decay rate at 80 °C
Dalet, Corinne. "Gestion de l'eau dans un système pile à combustible pour traction automobile : transferts couplés dans un humidificateur membranaire". Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10136/document.
This report presents a synthesis of works carried out in order to solve the water management problematic in a PEM fuel cell system. An analysis of the different components of the system air line, and more specifically the membrane humidifier, is realized in order to determine the architecture allowing the optimal moisture content of air upstream the fuel cell whatever the operating conditions. This study involves the description and the understanding of coupled heat and mass transfers within the humidifier, through numerical and experimental approaches. The numerical section contains a model of coupled transfer through a Nafion membrane. Associated with a thermodynamic analysis of the humidifier, it allows to define two parameters characterizing respectively the mass exchanges and the heat transfers, according to the inlet conditions of the fluids or as well as to the exchanger geometry. These parameters turn out to be useful design tools. The experimental section allows to estimate the interactions between a fuel cell, the humidifier and the other air line components. Besides the analysis of components response to a current intensity variation, the investigations allowed to demonstrate that the operating conditions of the system is compatible with the chosen humidification technology
Taleb, Miassa. "Exploitation des mesures électriques en vue de la surveillance et du diagnostic en temps réel des piles à combustible pour application transport automobile". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLC010/document.
In the current global energy context, proton exchange membrane fuel cells represent a promising solution to the future development of a new generation of electrified vehicles, allowing greater autonomy than electrified vehicles using batteries.Nevertheless, the large-scale development of fuel cells remains limited due to some technological locks, such as water management. To enable mass production of fuel cells, such problems must be solved. Several working axes may be envisaged both on the hardware aspects of the fuel cell structure, and from the point of view of control, by developing algorithmic tools for monitoring the operating state of the system to detect any failures, or degradations that may occur.The work of this thesis falls within this second approach and focuses specifically on the identification of drying and drowning phenomena which can appear in a fuel cell, to diagnose any moisture problems leading to yield reduction.The methods developed in this work are based on the monitoring of relevant parameters of the fuel cell model which changes, compared to reference values, are characteristic of the state of the fuel cell hydration.The real-time monitoring of these parameters can highlight the drying and drowning phenomena.Adopted models for this work are based on a representation of the electrical impedance of the fuel cell.Thus, following this approach, the adopted strategy is then based on the development of two electrical models: an integer order model and a fractional order model. It appears that the second model formulation is closer to the physical reality of transport phenomena occurring in the fuel cell. It allows a better representation of the fuel cell behavior in time and frequency domain. Indeed, the analyzes based on experimental results performed using a single fuel cell (100 cm2 active area designed by UBzM company) have validated that the fractional order model, in return for an increase of complexity, allows better reproduce, in the one hand of the fuel cell time-series voltage response (voltage monitoring for a given current profile), on the other hand a better approximation of the measured impedance. Conventional and of fractional order parametric identification methods are then used to extract the model’s parameters from time-series experimental data (voltage / current from the battery) or frequency data (impedance spectroscopy).A sensitivity analysis allows then the defining of the most indicative parameters of the drowning and drying phenomena. The evolution of these parameters associated with the voltage and impedance spectrum of the fuel cell are then combined to build a diagnosis strategy of the fuel cell water management
Suárez, Santiago Hernán. "Gestion de l'énergie d'un système de piles à combustible alimenté par un réservoir d'hydrogène à hydrure métallique". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2022. http://www.theses.fr/2022UBFCA019.
This thesis work is part of the contribution to the scientific and technological advancement of the use of renewable energies based on a PEMFC fuel cell system powered by hydrogen from a metal hydride tank. The first part of the work was devoted to the characterisation of two commercial tanks of this technology with emphasis on their performance degradation. Stochastic methods were used to study the impact of cycling (charge/discharge) on the variation of the tanks' intrinsic parameters. In a second part, the results of this study were implemented through an energy model of the tank developed under the MATLAB /Simulink environment. The model was validated experimentally on a specially designed test bench. The ageing phenomenon was highlighted, providing a significant advance, particularly with a view to the industrialisation of this type of solution. Finally, the thermo-fluidic coupling between the fuel cell and the hydride tank was experimented, modelled and numerically simulated
Tayouo, Djinsu Russell. "Synthèses et caractérisations de nouvelles membranes fluorées porteuses de groupements acide phosphonique pour une application en pile à combustible type PEMFC". Montpellier 2, 2009. http://www.theses.fr/2009MON20171.
This thesis is a continuation of research conducted on the development of new proton exchange membrane fuel cell (PEMFC), bearing phosphonic acid as protogenic groups capable to work at high temperature (> 100°C) and low RH (<50%). The objective of this work is to propose new fluorinated copolymers bearing pendant phosphonic acid groups for fuel cell membranes. For this, the radical polymerization in solution of alternating copolymers and terpolymers from vinyl ethers (CEVE and EVE) and CTFE was first performed. Five phosphonate fluorinated copolymers were then obtained quantitatively according to Michaelis-Arbuzov reaction via an iodinated intermediate, and efficiently hydrolyzed by silylation, leading to the corresponding phosphonic acid whose rates, location and distribution are well controlled. This new fluorinated polymer was perfectly characterized by means of 1H, 19F and 31P NMR. Flexible and mechanically strong membranes were obtained by casting 27 wt % solutions of alternated fluorinated phosphonic acid copolymers in DMSO at 120°C. The membrane containing the highest IEC (6. 88 meq/g) shows the highest value of proton conductivity at 25°C and 98% RH (20 mS/cm). On the other hand, at high temperature (120°C) and low RH (25%) this conductivity decrease drastically to 0. 25 mS/cm
Castanheira, Luis Filipe Rodrigues. "Corrosion of high surface area carbon supports used in proton-exchange membrane fuel cell electrodes". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI084/document.
This thesis investigates the degradation mechanism of high surfacearea carbon (HSAC) supports used in proton-exchange membrane fuel cell (PEMFC) electrodes. The structural and the chemical properties of different HSAC supports were established. The effectof the Nafion® ionomer used as a proton conductor, the gas atmosphere, the upper potential limit and the intermediate electrochemical characterizations used to monitor the changes ofthe electrochemical surface area during accelerated stress tests(ASTs) were investigated. The long-term physical and chemical changes of Pt/HSAC electrocatalysts were investigated insimulated PEMFC operating conditions. Using Raman spectroscopy, we showed that the COR is strongly structure sensitive and proceeds more rapidly on disordered domains of the HSAC (amorphous carbon and defective graphite crystallites) thanon graphitic domains. The coverage with carbon surface oxides was investigated with X-ray photoelectron spectroscopy and bridged tothe intensity of the quinone/hydroquinone (Q/HQ) peak monitored by cyclic voltammetry. Finally, the analyses realized on membrane electrode assemblies operated for 12,860h disclosed a perfect agreement between model and real PEMFC operating conditions, and confirmed the structural dependency of the COR kinetics
Andre, Johan. "Optimisation des propriétés de conduction électrique et de passivité d'aciers inoxydables pour la réalisation de plaques bipolaires de pile à combustible de type pemfc". Grenoble INPG, 2007. http://www.theses.fr/2007INPG0105.
PEM fuel cells have to comply with stringent cost, performance, and durability criteria. Thus, the goal of this PhD was to optimize electrical conduction properties and passivity of stainless steels (SS) for PEMFC bipolar plates. This work presents the possible problems when using SS plates and corresponding solutions, SS passive film properties, as weIl as their modifications by low cost surface treatments. Material characterizations were performed, allowing to study the behaviour of two alloys in different states and conditions representative of a PEMFC media. The plate industrial state is not convenient for direct use in fuel cell. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side
Tan, Chiuan Chorng. "A new concept of regenerative proton exchange membrane fuel cell (R-‐PEMFC)". Thesis, La Réunion, 2015. http://www.theses.fr/2015LARE0012.
The past works found in the literature have focused on either PEM fuel cell or electrolyzer-PEM. Some of the papers even studied the unitised reversible regenerative fuel cell (URFC) and the solar power hydrogen system by integrating both fuel cell and electrolyzer. Unlike the URFC, our design has an individual compartment for each PEMFC and E-PEM systems and named Quasi-URFC. With this new concept, the main objective is to reduce the cost of regenerative fuel cell (RFC) by minimizing the ratio of the catalyst’s geometric surface area of the membrane electrode assembly (MEA) of both cell modes. Apart from that, we also aim to build a compact, light and portable RFC.This research work is divided into three parts: the modeling, assembly of the prototype and the experimentation work. As for the modeling part, a 2D multi-physics model has been developed in order to analyze the performance of a three chamber-regenerative fuel cell, which consists of both fuel cell and electrolyzer systems. This numerical model is based on solving conservation equations of mass, momentum, species and electric current by using a finite-element approach on 2D grids. Simulations allow the calculation of velocity, gas concentration, current density and potential's distributions in fuel cell mode and electrolysis mode, thus help us to predict the behavior of Quasi-RFC. Besides that, the assembly of the first prototype of the new concept of regenerative fuel cell has been completed and tested during the three years of PhD studies. The experimental results of the Three-Chamber RFC are promising in both fuel cell and electrolyzer modes and validate the simulation results that previously obtained by modeling
Fofana, Daouda. "Modélisation et conception d'électrode cathodique multicouche à faible quantité de platine et haute performance pour les piles à combustible à membrane échangeuse de proton (PEMFC)". Thèse, Université du Québec à Trois-Rivières, 2013. http://depot-e.uqtr.ca/6975/1/030596129.pdf.
Rouhet, Marlene. "Etude de l'influence des protons sur la réduction de l'oxygène dans des couches catalytiques ordonnées en vue d'une application en pile à combustible". Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAF031/document.
Ordered catalytic layers based on vertically aligned carbon nanofilaments with Pt nanoparticles demonstrate high efficiency for oxygen transport and Pt utilization in the catalytic layer. Electrochemical studies combined with mathematical modeling confirm the influence of the proton transport on surface red-ox processes, the kinetics and the mechanism of the O2 reduction (ORR), and on the H2O2 escape. We show that (i) protons are involved in the rate-determining step of the O2 reduction, (ii) for pH ≥ 3, a plateau corresponding to the diffusion-limited current of protons is observed and, (iii) for pH ≥ 3, the mechanism of the ORR involves not only the hydronium ions but also water molecules. The integration of these catalytic layers in high temperature PEMFCs was then studied. The performance is slightly lower than that for conventional layers. An optimization work is required to improve the performance
Daoudi, Meriem. "Performances et durabilité des membranes alternatives aux membranes PFSA". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0011.
The main objective of this thesis is to find a compromise between durability, cost, and eventually the ability to sustain high temperatures ionomer membranes used in PEMFC (Proton Exchange Membrane Fuel Cell). This work focused on sulfonated poly (ether ether ketone) membranes (sPEEK), which were chosen because of their good mechanical properties and high temperature resistance. However, sPEEK membranes suffer from a poor chemical stability, compared to the reference PFSA (PerFluoroSulfonic Acid) membranes. In order to overcome this problem, two approaches have been developed: pretreatment and/or hybridization of sPEEK membranes.The impact of sulfonated poly (ether ether ketone) membranes pretreatments on their functional properties, chemical structure and fuel cell performances was studied. Several physico-chemical characterization techniques as well as electrochemical diagnostic tools were used to correlate the cell performance with the sorption and transport properties of tested membranes.Subsequently, the durability of the best of these samples was studied via ex-situ and in-situ approaches. The ex-situ approach provided a first insight into the chemical stability of the membranes. In addition, the in-situ degradation tests allowed to evaluate the durability of the membranes under chemical and mechanical stresses very close from those encountered during fuel cell cells operation. For this purpose, an accelerated aging test was developed, combining potential cycling, humidity cycling and open-circuit prolonged hold.Finally, the second approach consists, in addition to the application of a pretreatment, in the hybridization of the membranes by sol-gel processes. Several precursors with sacrificial or redox functions were impregnated into the sulfonated poly (ether ether ketone) membranes. The analysis of fuel cell performances and membrane durability after applying the accelerated stress test have highlighted the efficiency of this approach: the performance and durability of some hybrid membranes even exceeded those of the reference PFSA membranes
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.
In 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
Souissi, Mohamed Ali. "Développement et caractérisation de matériaux électriquement conducteurs à base de mélanges polymères pour plaques bipolaires de piles à combustible de type PEMFC". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28082/28082.pdf.
Nguyen, Luc. "Développement et caractérisation de nouveaux matériaux à base de PET, PVDF, et de mélanges PET/PVDF, pour la fabrication de plaques bipolaires pour piles à combustibles à membrane échangeuse de protons, PEMFC". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26799/26799.pdf.
Fortineau, Julien. "Caractérisation et contrôle ultrasonore in situ de membranes échangeuses de protons". Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4004/document.
No summary available
Carrère, Pierre. "Modelling and numerical simulation of water transfer in Proton Exchange Membrane Fuel Cells". Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0123.
Water management is considered as a key issue in order to improve Proton Exchange Membrane Fuel Cells efficiency and durability. One of the critical components regarding this issue is the athode Gas Diffusion Layer (GDL). In this context, the main goal of the PhD work is to improve the understanding of the mechanisms responsible for the liquid water formation and transport in the cathode GDL. To this end, a Mixed liquid-vapour Injection Pore Network Model (MIPNM) is developed. This new model enables one to simulate the liquid water formation and transport in the cathode GDL for a larger range of operating conditions (temperature, current density and channel relative humidity) than in previous works. Different regimes of water formation and transport are identified and described. In a second part, the PhD work focus on the impact of the GDL hydrophobic treatment. Currently commercialized GDLs are rendered hydrophobic by coating Polytetrafluoroethylene (PTFE) onto the hydrophilic carbon fibres. It has been reported that the coating can be nonuniform on fresh GDLs and also that the coating can be altered during the operation of the fuel cell. The impact of these two phenomena on the liquid water distribution and on the reactant gas access to the catalyst layer is studied using the MIPNM for mixed wettability networks. In a third part, a work aiming at the improvement of PEMFC efficiency is developed. The goal is to optimise the reactant gas access to the catalyst layer by modifying the microstructure of GDLs. This is performed by coupling the PNM with a genetic algorithm. In a complementary study, the improvement of the reactant gas access is studied through modifications of the GDL wettability properties. Finally, a 1D model of the whole anode-cathode assembly is developed so as to take into account both anode and cathode operating conditions. This 1D model is coupled with the MIPNM in order to assess the impact of the anode operating conditions on the liquid water distribution in the cathode GDL
Duclos, Lucien. "Vers l’éco-conception des piles à combustible : développement d'un procédé de recyclage des catalyseurs des systèmes de PEMFC à base de platine". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI051/document.
The proton exchange membrane fuel cells (PEMFC) can be used to convert chemical energy into electrical energy using hydrogen which can be produced from renewable sources. Platinum (Pt) is the best catalyst used to perform PEMFC electrochemical reaction catalysis. However Pt resources are low and his production (extraction and refining) is complex. Moreover the platinum price represents an important part of the PEMFC stack cost. Nowadays this technology is too expensive to be competitive with conventional energy conversion systems, and cannot be commercialized at a large scale. In addition, PEMFC electrode platinum loading could not be reduced without affecting the system performance and durability. Thus PEMFC production cost could be reduced by recovering platinum from used fuel cells.The main goal of this thesis was to develop a platinum recovery way from fuel cells membrane electrodes-assemblies (MEAs). In order to achieve this objective the following steps were combined in a hydrometallurgical process: (i) leaching, (ii) separation, (iii) recovery. Several alternatives were tested for each step: leaching (HCl/H2O2, HCl/HNO3), separation (resin or solvent), and platinum recovery (as nanoparticles or as a complex). These platinum recovery steps were optimized using Pt/C catalysts and synthetic solutions. Then life-cycle analysis (LCA) methodology has been used to help with the process selection.Finally, about 76% of the platinum contained in multi-metallic catalysts (PtCo/C) MEAs has been recovered. The following path has been followed in this case: (i) dissolution in HCl/H2O2 solution, (ii) separation from cobalt with an ion exchange resin, (iii) recovery has nanoparticles using the polyol process. The LCA study final results showed that a significant reduction of PEMFC MEA life-cycle environmental impact could be achieved by recycling Pt at these systems end-of-life
Bassil, Joëlle. "Développement par procédés plasma de polymères conducteurs protoniques de type phosphonique pour piles à combustible". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20029/document.
The proton exchange membrane is a key component in the PEMFC-type fuel cell; it plays a decisive role as electrolyte medium for proton transport and barrier to avoid the direct contact between fuel and oxygen. The Nafion® is one of the most extensively studied proton exchange membrane for PEMFC applications. However, it has a number of drawbacks that need to be overcome, especially the poor performance at temperature above 80°C. That's why the development of effective and low cost membranes for fuel cell turned to be a challenge for the membrane community in the last years. Phosphonic acid derivatives are considered suitable candidates as ionomers for application in PEMFC at high temperature (> 80°C) thanks to their efficient proton transport properties under low humidity condition due to their amphoteric character.In this work, plasma polymers containing phosphonic acid groups have been successfully prepared using dimethyl allylphosphonate as a single precursor demonstrating the feasibility of plasma process for the manufacture of proton exchange membranes. Moreover, plasma polymers properties have been investigated as a function of the plasma conditions. The evolution of the films growth rate on three different supports as a function of the plasma discharge power is bimodal, with a maximum (close to 30 nm min-1 on Si) at 60 W. The chemical composition of plasma materials (investigated by FTIR, EDX and XPS) is quite homogeneous from the surface to the bulk; it is characterized by a wide variety of bond arrangements, in particular the presence of phosphonate and phosphonic acid groups which are above all concentrated in the plasma film synthesized at 60 W, characterized by the highest ion exchange capacity (4.65 meq g-1) and the highest proton conductivity (0.08 mS cm-1 at 90°C and 30% RH). TGA analysis has shown that phosphonic acid-based plasma polymers retain water and don't decompose up to 150 °C, which reveals a satisfying thermal stability for the fuel cell application. In terms of fuel retention, plasma films are intrinsically highly performing (methanol, ethanol and glycerol permeabilities being 40 to 235 lower than that of Nafion®211). The plasma films were deposited on fuel cell electrodes (E-TEK®) as binding agents. We have noticed that the phosphonic binder has a sufficient proton conductivity to allow proton transport at the electrode-membrane interface.A second part of this work concerns the surface treatment by plasma process of a conventional phosphonated membrane for improvement of thermal stability and fuel retention. TGA analysis has shown a slight improvement of the thermal stability for the treated membrane. Methanol and ethanol permeabilities tests show that the plasma-modified membrane is 2 to 4 times less permeable than the non-modified membrane. The treatment at 60 W shows the lowest fuel diffusion coefficients (DMeOH = 9.10-12 m2.s-1 and DEtOH = 6.10-12 m2.s-1). Fuel cell tests were realized showing better performance for the modified membrane compared to the non-modified one