Chang-Whan Lee, Dong-Yol Yang, Jong-Seung Park, Y. Kim, T. Lee
{"title":"Investigation Into Mechanical Behavior of the Current Collector for the Molten Carbonate Fuel Cell Through Finite Element Analysis Using Hexahedral Mesh Coarsening","authors":"Chang-Whan Lee, Dong-Yol Yang, Jong-Seung Park, Y. Kim, T. Lee","doi":"10.1115/1.4028939","DOIUrl":"https://doi.org/10.1115/1.4028939","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"061005"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028939","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Several experiments have proved that water in liquid phase can be present at the anode of a PEM fuel cell due to vapor condensation resulting in mass transport losses. Nevertheless, it is not yet well understood where exactly water tends to cumulate and how the design of the gas channel (GC) and gas diffusion layer (GDL) could be improved to limit water cumulation. In the present work, a three-dimensional lattice Boltzmann based model is implemented in order to simulate the water cumulation at the GC–GDL interface at the anode of a PEM fuel cell. The numerical model incorporates the H 2 –H 2 O mixture equation of state and spontaneously simulates phase separation phenomena. Different simulations are carried out varying pressure gradient, pore size, and relative height of the GDL. Results reveal that, once saturation conditions are reached, water tends to cumulate in two main regions: the upper and side walls of the GC and the GC–GDL interface, resulting in a limitation of the reactant diffusion from the GC to the GDL. Interestingly, the cumulation of liquid water at the interface is found to diminish as the relative height of the GDL increases.
{"title":"Lattice Boltzmann Modeling of Water Cumulation at the Gas Channel-Gas Diffusion Layer Interface in Polymer Electrolyte Membrane Fuel Cells","authors":"D. Maggiolo, A. Marion, M. Guarnieri","doi":"10.1115/1.4028952","DOIUrl":"https://doi.org/10.1115/1.4028952","url":null,"abstract":"Several experiments have proved that water in liquid phase can be present at the anode of a PEM fuel cell due to vapor condensation resulting in mass transport losses. Nevertheless, it is not yet well understood where exactly water tends to cumulate and how the design of the gas channel (GC) and gas diffusion layer (GDL) could be improved to limit water cumulation. In the present work, a three-dimensional lattice Boltzmann based model is implemented in order to simulate the water cumulation at the GC–GDL interface at the anode of a PEM fuel cell. The numerical model incorporates the H 2 –H 2 O mixture equation of state and spontaneously simulates phase separation phenomena. Different simulations are carried out varying pressure gradient, pore size, and relative height of the GDL. Results reveal that, once saturation conditions are reached, water tends to cumulate in two main regions: the upper and side walls of the GC and the GC–GDL interface, resulting in a limitation of the reactant diffusion from the GC to the GDL. Interestingly, the cumulation of liquid water at the interface is found to diminish as the relative height of the GDL increases.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"061008"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028952","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design Approach for the Development of the Flow Field of Bipolar Plates for a PEMFC Stack Prototype","authors":"P. Sala, P. G. Stampino, G. Dotelli","doi":"10.1115/1.4028150","DOIUrl":"https://doi.org/10.1115/1.4028150","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"31 1","pages":"061003"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028150","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63486424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of Operating Conditions on Direct Methanol Fuel Cell Performance Using Nafion-Based Polymer Electrolytes","authors":"S. Lue, W. Hsu, Chen Chao, K. Mahesh","doi":"10.1115/1.4028611","DOIUrl":"https://doi.org/10.1115/1.4028611","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"52 1","pages":"061004"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028611","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy-saving evaluation of sofc cogeneration systems with solar cell and battery","authors":"Akira Yoshida, Koichi Ito, Y. Amano","doi":"10.1115/1.4028948","DOIUrl":"https://doi.org/10.1115/1.4028948","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"55 1","pages":"061006"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Parametric Sensitivity Tests—European Polymer Electrolyte Membrane Fuel Cell Stack Test Procedures","authors":"Samuel Simon Araya, S. J. Andreasen, S. Kær","doi":"10.1115/1.4028949","DOIUrl":"https://doi.org/10.1115/1.4028949","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"061007"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028949","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Comparisons of Electrical Performance and Impedance Spectrum for Two Commercial Cells","authors":"Y. Cheng, Shih-Wei Cheng, Ruey‐yi Lee","doi":"10.1115/1.4027394","DOIUrl":"https://doi.org/10.1115/1.4027394","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"051002"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4027394","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63484818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Koshekov, Yu. N. Klikushin, V. Kobenko, Y. Evdokimov, A. Demyanenko
The possibility to use instruments of identification measurement theory to solve the problems of diagnostics of fuel cells according to their noise characteristics is considered in this paper. The offered techniques of diagnostic signals processing are based on the identification measurement of time and probabilistic characteristics, the comparison of model signals with the ones under analysis according to the reading values, the classification of signals according to the waveform parameter and characteristic frequency, the building of hierarchical structures, and the assessment of the signal structures by the fractal indices. All proposed techniques are applicable for the diagnosis of a fuel cell, but thanks to graphical representation of classification trees of noise signals, the more efficient method for experts is the one based on the building of hierarchical structures.
{"title":"Fuel Cell Diagnostics Using Identification Measurement Theory","authors":"K. Koshekov, Yu. N. Klikushin, V. Kobenko, Y. Evdokimov, A. Demyanenko","doi":"10.1115/1.4027395","DOIUrl":"https://doi.org/10.1115/1.4027395","url":null,"abstract":"The possibility to use instruments of identification measurement theory to solve the problems of diagnostics of fuel cells according to their noise characteristics is considered in this paper. The offered techniques of diagnostic signals processing are based on the identification measurement of time and probabilistic characteristics, the comparison of model signals with the ones under analysis according to the reading values, the classification of signals according to the waveform parameter and characteristic frequency, the building of hierarchical structures, and the assessment of the signal structures by the fractal indices. All proposed techniques are applicable for the diagnosis of a fuel cell, but thanks to graphical representation of classification trees of noise signals, the more efficient method for experts is the one based on the building of hierarchical structures.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"051003"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4027395","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63484834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yusuke Kai, Yukiya Kitayama, M. Omiya, T. Uchiyama, H. Kumei
The mechanical reliability of the membrane electrode assembly (MEA) in polymer electrolyte fuel cells (PEFCs) is a major concern with respect to fuel cell vehicles. When PEFCs generate power, water is generated. The proton exchange membrane (PEM) swells in wet conditions and shrinks in dry conditions. These cyclic conditions induce mechanical stress in the MEA, and cracks are formed. Failure of the MEA can result in leaking of fuel gases and reduced output power. Therefore, it is necessary to determine the mechanical reliability of the MEA under various mechanical and environmental conditions. The purpose of the present paper is to observe the deformation behavior of the MEA under humidity cycles. We have developed a device in which the constrained condition of the GDL is modeled by carbon bars of 100 to 500 μm in diameter. The carbon bars are placed side by side and are pressed against the MEA. The device was placed in a temperature and humidity controlled chamber, and humidity cycles were applied to the specimen. During the tests, cross sections of the specimen were observed by microscope, and the strain was calculated based on the curvature of the specimen. The temperature in the test chamber was varied from 25 to 80 °C, and the relative humidity was varied from 50 to 100%RH, and the wet condition was also investigated. The results revealed that the MEA deformed significantly by swelling and residual deformation was observed under the dry condition, even for one humidity cycle. The crack formation criteria for one humidity cycle corresponded approximately with those of the static tensile tests. The results of the humidity cycle tests followed Coffin–Manson law, and the number of cycles until crack formation corresponded approximately with the results of the mechanical fatigue tests. These results will be valuable in the critical design of durable PEFCs.
{"title":"In Situ Observation of Deformation Behavior of Membrane Electrode Assembly Under Humidity Cycles","authors":"Yusuke Kai, Yukiya Kitayama, M. Omiya, T. Uchiyama, H. Kumei","doi":"10.1115/1.4028155","DOIUrl":"https://doi.org/10.1115/1.4028155","url":null,"abstract":"The mechanical reliability of the membrane electrode assembly (MEA) in polymer electrolyte fuel cells (PEFCs) is a major concern with respect to fuel cell vehicles. When PEFCs generate power, water is generated. The proton exchange membrane (PEM) swells in wet conditions and shrinks in dry conditions. These cyclic conditions induce mechanical stress in the MEA, and cracks are formed. Failure of the MEA can result in leaking of fuel gases and reduced output power. Therefore, it is necessary to determine the mechanical reliability of the MEA under various mechanical and environmental conditions. The purpose of the present paper is to observe the deformation behavior of the MEA under humidity cycles. We have developed a device in which the constrained condition of the GDL is modeled by carbon bars of 100 to 500 μm in diameter. The carbon bars are placed side by side and are pressed against the MEA. The device was placed in a temperature and humidity controlled chamber, and humidity cycles were applied to the specimen. During the tests, cross sections of the specimen were observed by microscope, and the strain was calculated based on the curvature of the specimen. The temperature in the test chamber was varied from 25 to 80 °C, and the relative humidity was varied from 50 to 100%RH, and the wet condition was also investigated. The results revealed that the MEA deformed significantly by swelling and residual deformation was observed under the dry condition, even for one humidity cycle. The crack formation criteria for one humidity cycle corresponded approximately with those of the static tensile tests. The results of the humidity cycle tests followed Coffin–Manson law, and the number of cycles until crack formation corresponded approximately with the results of the mechanical fatigue tests. These results will be valuable in the critical design of durable PEFCs.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"051006"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63486477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To investigate the degradation mechanism of the as-prepared Pd/C catalyst, in situ and ex situ accelerated stress tests were carried out via potential cycling. Durability tests of the single cells with Pd/C catalysts were performed through an interval constant current density mode. Electrochemical impedance spectroscopy (EIS) was applied to measure the impedance of the single cell during degradation tests. Results indicate that the degradation of Pd/C catalyst may be attributed to the phase transition of absorbed α-phase PdH to β-phase PdH, the dissolution of Pd metal, and the size increase of Pd nanoparticles. Moreover, the degradation of single cell may be predominantly ascribed to the degradation of catalyst, the deterioration of contact between electronic/ionic conductors, as well as the flooding of gas diffusion channels.
{"title":"In Situ and Ex Situ Studies on the Degradation of Pd/C Catalyst for Proton Exchange Membrane Fuel Cells","authors":"Yongfu Tang, Shichun Mu, Sheng-xue Yu, Yufeng Zhao, Hongchao Wang, Faming Gao","doi":"10.1115/1.4027708","DOIUrl":"https://doi.org/10.1115/1.4027708","url":null,"abstract":"To investigate the degradation mechanism of the as-prepared Pd/C catalyst, in situ and ex situ accelerated stress tests were carried out via potential cycling. Durability tests of the single cells with Pd/C catalysts were performed through an interval constant current density mode. Electrochemical impedance spectroscopy (EIS) was applied to measure the impedance of the single cell during degradation tests. Results indicate that the degradation of Pd/C catalyst may be attributed to the phase transition of absorbed α-phase PdH to β-phase PdH, the dissolution of Pd metal, and the size increase of Pd nanoparticles. Moreover, the degradation of single cell may be predominantly ascribed to the degradation of catalyst, the deterioration of contact between electronic/ionic conductors, as well as the flooding of gas diffusion channels.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"051004"},"PeriodicalIF":0.0,"publicationDate":"2014-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4027708","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63485373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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