In this study, local area water content distribution under various gas purging conditions are experimentally analyzed for the first time. The local high frequency resistance (HFR) is measured using novel micro sensors. The results reveal that the liquid water removal rate in a membrane electrode assembly (MEA) is non-uniform. In the under-the-channel area, the removal of liquid water is governed by both convective and diffusive flux of the through-plane drying. Thus, almost all of the liquid water is removed within 30 s of purging with gas. However, liquid water that is stored in the under-the-rib area is not easy to remove during 1 min of gas purging. Therefore, the re-hydration of the membrane by internal diffusive flux is faster than that in the under-the-channel area. Consequently, local fuel starvation and membrane degradation can degrade the performance of a fuel cell that is started from cold.
References
[1]
Liu, Z.Y.; Brandy, B.K.; Carter, R.N.; Litteer, B.; Budinski, M.; Hyun, J.K.; Muller, D.A. Characterization of carbon corrosion-induced structural damage of PEM fuel cell cathode electrodes caused by local fuel starvation. J. Electrochem. Soc 2008, 55, B979–B984.
[2]
Tang, H.; Qi, Z.; Ramani, M.; Elter, J.F. PEM fuel cell cathode carbon corrosion due to the formation of air/fuel boundary at the anode. J. Power Sources 2006, 158, 1306–1312.
[3]
Ge, S.; Wang, C.Y. In situ imaging of liquid water and ice formation in an operating PEFC during cold start. Electrochem. Solid State Lett 2006, 9, A499–A503.
[4]
Ge, S.; Wang, C.Y. Characteristics of subzero startup and water/ice formation on the catalyst layer in a polymer electrolyte fuel cell. Electrochem. Acta 2007, 52, 4825–4835.
[5]
Tajiri, K.; Wang, C.Y.; Tabuchi, Y. Water removal from a PEFC during gas purge. Electrochem. Acta 2008, 53, 6337–6343.
[6]
Tajiri, K.; Tabuchi, Y.; Kagami, F.; Takahashi, S.; Yoshizawa, K.; Wang, C.Y. Effects of operating and design parameters on PEFC cold start. J. Power Sources 2007, 165, 279–286.
[7]
Oszcipok, M.; Riemann, D.; Kronenwett, U.; Kreideweis, M.; Zedda, M. Statistic analysis of operational influences on the cold start behavior of PEM fuel cells. J. Power Sources 2005, 145, 407–415.
[8]
Hou, J.; Yi, B.; Yu, H.; Hao, L.; Song, W.; Fu, Y.; Shao, Z. Investigation of resided water effects on PEM fuel cell after cold start. J. Hydrog. Energy 2007, 32, 4503–4509.
[9]
Jiang, F.M.; Wang, C.Y. Potentiostatic start-up of PEMFCs from subzero temperatures. J. Electrochem. Soc 2008, 155, B743–B751.
[10]
Sinha, P.K.; Wang, C.Y. Two-phase modeling of gas purge in a polymer electrolyte fuel cell. J. Power Sources 2008, 183, 609–618.
[11]
Ghosh, P.C.; Wüster, T.; Dohle, H.; Kimiaie, N.; Mergel, J.; Stolten, D. In situ approach for current distribution measurement in fuel cells. J. Power Sources 2006, 154, 184–191.
[12]
Schulze, M.; Gülzow, E.; Sch？nbauer, St.; Kn？ri, T.; Reissner, R. Segmented cells as tool for development of fuel cells and error prevention/prediagnostic in fuel cell stacks. J. Power Sources 2007, 173, 19–27.
[13]
Eckl, R.; Grinzinger, R.; Lehnert, W. Current distribution mapping in polymer electrolyte fuel cells—a finite element analysis of measurement uncertainty imposed by lateral currents. J. Power Sources 2006, 154, 171–179.
[14]
Sinha, P.K.; Wang, C.Y. Gas purge in a polymer electrolyte fuel cell. J. Electrochem. Soc 2007, 154, B1158–B1166.
