The Experts below are selected from a list of 7539 Experts worldwide ranked by ideXlab platform
Olivier Lottin - One of the best experts on this subject based on the ideXlab platform.
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local potential evolutions during proton exchange membrane fuel cell operation with dead ended Anode part ii aging mitigation strategies based on water management and nitrogen crossover
Journal of Power Sources, 2017Co-Authors: Sylvain Didierjean, Sofyane Abbou, Olivier Lottin, Jérôme Dillet, Gaël MaranzanaAbstract:Abstract Proton exchange membrane (PEM) fuel cells operate with dead-ended Anode in order to reduce system cost and complexity when compared with hydrogen re-circulation systems. In the first part of this work, we showed that localized fuel starvation events may occur, because of water and nitrogen accumulation in the Anode Side, which could be particularly damaging to the cell performance. To prevent these degradations, the Anode compartment must be purged which may lead to an overall system efficiency decrease because of significant hydrogen waste. In the second part, we present several purge strategies in order to minimize both hydrogen waste and membrane-electrode assembly degradations during dead-ended Anode operation. A linear segmented cell with reference electrodes was used to monitor simultaneously the current density distribution along the gas channel and the time evolution of local Anode and cathode potentials. To asses MEA damages, Platinum ElectroChemical Surface Area (ECSA) and cell performance were periodically measured. The results showed that dead-end mode operation with an Anode plate maintained at a temperature 5 °C hotter than the cathode plate limits water accumulation in the Anode Side, reducing significantly purge frequency (and thus hydrogen losses) as well as MEA damages. As nitrogen contribution to hydrogen starvation is predominant in this thermal configuration, we also tested a microleakage solution to discharge continuously most the nitrogen accumulating in the Anode Side while ensuring low hydrogen losses and minimum ECSA losses provided the right microleakage flow rate is chosen.
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Perfluorosulfonic acid membrane degradation in the hydrogen inlet region: A macroscopic approach
International Journal of Hydrogen Energy, 2016Co-Authors: Gilles De Moor, Olivier Lottin, Jérôme Dillet, Gaël Maranzana, C. Bas, N. Charvin, N. Caqué, E. Rossinot, L. FlandinAbstract:This study focuses on the characterization of two complete stacks of a proton exchange membrane fuel cell that have operated in stationary mode for 12,860 h. We compare cell voltage, and in situ and ex situ leak tests with local cell performance from a segmented cell, showing large differences in degradation between the stacks. Cells near the warmest region show more membrane degradation in the hydrogen inlets. We build a membrane thickness profile over a large area from thousands of optical microscopy images, covering seven channels and lands around the hydrogen inlet region, and identify a dramatic difference between channels 1 and 2, where dry hydrogen enters, and channel 3, where hydrogen has travelled 26 cm. Using a polytetrafluoroethylene reinforced membrane, we discriminate thickness variation for each layer and we show that degradation commences from the Anode Side.
Tatsuhiro Okada - One of the best experts on this subject based on the ideXlab platform.
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theory for water management in membranes for polymer electrolyte fuel cells part 1 the effect of impurity ions at the Anode Side on the membrane performances
Journal of Electroanalytical Chemistry, 1999Co-Authors: Tatsuhiro OkadaAbstract:Abstract Performance degradation in membranes for polymer electrolyte fuel cells was discussed theoretically for the case where the membrane is contaminated with foreign impurity cations at the cathode Side. Water transport in a two-cation system membrane was conSidered by assuming an ‘infected zone’ of finite thickness. Four kinds of boundary value problems were solved, and analytical formulae derived for the water concentration profile across the membrane. The water content in the membrane, the net water flux and the membrane resistance overvoltage were calculated systematically as functions of several relevant parameters in fuel cell operations. Localized contamination at the cathode ∣ membrane interface turned out to be even more serious than the uniform contamination of the membrane or localized contamination at the Anode Side. It is noted that special caution should be directed in order to avoid the membrane contamination, especially at the cathode Side, because contaminant will easily enter from the air stream through the cathode compartment of a fuel cell.
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theory of water management at the Anode Side of polymer electrolyte fuel cell membranes
Journal of Electroanalytical Chemistry, 1996Co-Authors: Tatsuhiro Okada, Yoshikazu TanabeAbstract:Abstract The behavior of the water transport and the water concentration profile at the Anode Side of the membrane in a polymer electrolyte fuel cell is conSidered theoretically. A linear transport equation based on the diffusion of water and electroosmotic water drag was taken into account. Two kinds of boundary value problem were treated: (1) for semi-infinite boundary conditions, analytical solutions for water concentration at a given time and location were obtained, under either humidified or non-humidified conditions at the Anode Side of the membrane; (2) for finite boundary conditions, the steady-state water concentration profile was obtained with two kinds of boundary condition at the cathode Side. The effect of various fuel cell operation and membrane state parameters on the water concentration was evaluated in a systematic way. Among those parameters tested, the current density and water penetration parameters are essential in determining membrane water content. Membrane thickness and the diffusion coefficient of water are important parameters in the case of finite boundary conditions. It turned out that contamination of the membrane by foreign impurities (e.g. NaCl), even on the surface, will cause a serious effect on the water depletion at the Anode Side. Water supply from the Anode Side of the membrane results in a conSiderable improvement of the membrane state with regard to water depletion. Although the method was fairly simplified in comparison with the most detailed analysis of membrane water content, it gave explicit and easy-to-handle equations for the purpose of quantitative or semi-quantitative evaluation of the membrane water management in polymer electrolyte fuel cell operations.
Suresh G Advani - One of the best experts on this subject based on the ideXlab platform.
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in situ comparison of water content and dynamics in parallel single serpentine and interdigitated flow fields of polymer electrolyte membrane fuel cells
Journal of Power Sources, 2010Co-Authors: Dusan Spernjak, Ajay K Prasad, Suresh G AdvaniAbstract:Abstract Water content and dynamics were characterized and compared in situ by simultaneous neutron and optical imaging for three PEM fuel cell flow fields: parallel, serpentine, and interdigitated. Two independent sets of images were obtained simultaneously: liquid water dynamics in the flow field (channels and manifolds) were recorded by a digital camera through an optical window, while the through-thickness integrated water content was measured across the cell area by neutron imaging. Complementary data from the concurrent images allowed distinguishing between the water dynamics on the cathode and the Anode Side. The transient water content within the cell measured using neutron imaging is correlated with optical data as well as with temporal variations in the cell output and pressure differentials across the flow fields. Water dynamics on both the cathode and Anode Side were visualized and discussed. The serpentine cell showed stable output across the current range and the highest limiting current. Parallel and interdigitated cells exhibited substantially higher water contents and lower pressure differentials than the serpentine. Anode flooding significantly impeded their performance at high current. At moderate current, cell output correlated with the changes in water distribution in the cathode flow field rather than with the variations in the overall water content. Performance of the interdigitated cell was similar to the serpentine one in spite of the vastly different water contents. The cell's water-content response to a step-change in current revealed three distinct stages of water accumulation. Flow field configuration greatly affected both the amount of water accumulated in the cell and the duration of each stage.
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in situ comparison of water content and dynamics in parallel single serpentine and interdigitated flow fields of polymer electrolyte membrane fuel cells
Journal of Power Sources, 2010Co-Authors: Dusan Spernjak, Ajay K Prasad, Suresh G AdvaniAbstract:Abstract Water content and dynamics were characterized and compared in situ by simultaneous neutron and optical imaging for three PEM fuel cell flow fields: parallel, serpentine, and interdigitated. Two independent sets of images were obtained simultaneously: liquid water dynamics in the flow field (channels and manifolds) were recorded by a digital camera through an optical window, while the through-thickness integrated water content was measured across the cell area by neutron imaging. Complementary data from the concurrent images allowed distinguishing between the water dynamics on the cathode and the Anode Side. The transient water content within the cell measured using neutron imaging is correlated with optical data as well as with temporal variations in the cell output and pressure differentials across the flow fields. Water dynamics on both the cathode and Anode Side were visualized and discussed. The serpentine cell showed stable output across the current range and the highest limiting current. Parallel and interdigitated cells exhibited substantially higher water contents and lower pressure differentials than the serpentine. Anode flooding significantly impeded their performance at high current. At moderate current, cell output correlated with the changes in water distribution in the cathode flow field rather than with the variations in the overall water content. Performance of the interdigitated cell was similar to the serpentine one in spite of the vastly different water contents. The cell's water-content response to a step-change in current revealed three distinct stages of water accumulation. Flow field configuration greatly affected both the amount of water accumulated in the cell and the duration of each stage.
Dusan Spernjak - One of the best experts on this subject based on the ideXlab platform.
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in situ comparison of water content and dynamics in parallel single serpentine and interdigitated flow fields of polymer electrolyte membrane fuel cells
Journal of Power Sources, 2010Co-Authors: Dusan Spernjak, Ajay K Prasad, Suresh G AdvaniAbstract:Abstract Water content and dynamics were characterized and compared in situ by simultaneous neutron and optical imaging for three PEM fuel cell flow fields: parallel, serpentine, and interdigitated. Two independent sets of images were obtained simultaneously: liquid water dynamics in the flow field (channels and manifolds) were recorded by a digital camera through an optical window, while the through-thickness integrated water content was measured across the cell area by neutron imaging. Complementary data from the concurrent images allowed distinguishing between the water dynamics on the cathode and the Anode Side. The transient water content within the cell measured using neutron imaging is correlated with optical data as well as with temporal variations in the cell output and pressure differentials across the flow fields. Water dynamics on both the cathode and Anode Side were visualized and discussed. The serpentine cell showed stable output across the current range and the highest limiting current. Parallel and interdigitated cells exhibited substantially higher water contents and lower pressure differentials than the serpentine. Anode flooding significantly impeded their performance at high current. At moderate current, cell output correlated with the changes in water distribution in the cathode flow field rather than with the variations in the overall water content. Performance of the interdigitated cell was similar to the serpentine one in spite of the vastly different water contents. The cell's water-content response to a step-change in current revealed three distinct stages of water accumulation. Flow field configuration greatly affected both the amount of water accumulated in the cell and the duration of each stage.
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in situ comparison of water content and dynamics in parallel single serpentine and interdigitated flow fields of polymer electrolyte membrane fuel cells
Journal of Power Sources, 2010Co-Authors: Dusan Spernjak, Ajay K Prasad, Suresh G AdvaniAbstract:Abstract Water content and dynamics were characterized and compared in situ by simultaneous neutron and optical imaging for three PEM fuel cell flow fields: parallel, serpentine, and interdigitated. Two independent sets of images were obtained simultaneously: liquid water dynamics in the flow field (channels and manifolds) were recorded by a digital camera through an optical window, while the through-thickness integrated water content was measured across the cell area by neutron imaging. Complementary data from the concurrent images allowed distinguishing between the water dynamics on the cathode and the Anode Side. The transient water content within the cell measured using neutron imaging is correlated with optical data as well as with temporal variations in the cell output and pressure differentials across the flow fields. Water dynamics on both the cathode and Anode Side were visualized and discussed. The serpentine cell showed stable output across the current range and the highest limiting current. Parallel and interdigitated cells exhibited substantially higher water contents and lower pressure differentials than the serpentine. Anode flooding significantly impeded their performance at high current. At moderate current, cell output correlated with the changes in water distribution in the cathode flow field rather than with the variations in the overall water content. Performance of the interdigitated cell was similar to the serpentine one in spite of the vastly different water contents. The cell's water-content response to a step-change in current revealed three distinct stages of water accumulation. Flow field configuration greatly affected both the amount of water accumulated in the cell and the duration of each stage.
Sylvain Didierjean - One of the best experts on this subject based on the ideXlab platform.
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local potential evolutions during proton exchange membrane fuel cell operation with dead ended Anode part ii aging mitigation strategies based on water management and nitrogen crossover
Journal of Power Sources, 2017Co-Authors: Sylvain Didierjean, Sofyane Abbou, Olivier Lottin, Jérôme Dillet, Gaël MaranzanaAbstract:Abstract Proton exchange membrane (PEM) fuel cells operate with dead-ended Anode in order to reduce system cost and complexity when compared with hydrogen re-circulation systems. In the first part of this work, we showed that localized fuel starvation events may occur, because of water and nitrogen accumulation in the Anode Side, which could be particularly damaging to the cell performance. To prevent these degradations, the Anode compartment must be purged which may lead to an overall system efficiency decrease because of significant hydrogen waste. In the second part, we present several purge strategies in order to minimize both hydrogen waste and membrane-electrode assembly degradations during dead-ended Anode operation. A linear segmented cell with reference electrodes was used to monitor simultaneously the current density distribution along the gas channel and the time evolution of local Anode and cathode potentials. To asses MEA damages, Platinum ElectroChemical Surface Area (ECSA) and cell performance were periodically measured. The results showed that dead-end mode operation with an Anode plate maintained at a temperature 5 °C hotter than the cathode plate limits water accumulation in the Anode Side, reducing significantly purge frequency (and thus hydrogen losses) as well as MEA damages. As nitrogen contribution to hydrogen starvation is predominant in this thermal configuration, we also tested a microleakage solution to discharge continuously most the nitrogen accumulating in the Anode Side while ensuring low hydrogen losses and minimum ECSA losses provided the right microleakage flow rate is chosen.
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Effect of Gas Dilution on PEM Fuel Cell Performance and Impedance Response
Fuel Cells, 2006Co-Authors: Mathieu Boillot, N. Jatroudakis, Sylvain Didierjean, Philippe Carré, C. Bonnet, Francois LapicqueAbstract:In this work, an experimental study of gas dilution on the performance of a polymer electrolyte membrane (PEM) fuel cell was carried out. Impedance spectra were analysed depending on the dilution of either hydrogen or oxygen by nitrogen. By comparison of the impedance spectra obtained, the three loops were attributed to hydrogen oxidation, oxygen reduction and a low frequency diffusion process. Hydrogen oxidation was shown to be more complicated when the Anode Side was fed by a simulated reforming gas than with the same dilution rate with nitrogen.