We have developed hybrid gas channels for polymer electrolyte fuel cells (PEFCs) that can arbitrarily change the ratio of the flow rates between the interdigitated and parallel flows. We analyze flooding under the rib of the cathode separator using the interdigitated flow to find methods to improve the cell performance. The ratio of the rate of in-plane flow passing through the gas diffusion layer (GDL) under the rib of an operating cell to the rate of the in-plane flow of dry air without operation gives the cross-sectional area ratio of through-pores (A/A0) and flooding ratio (1 - A/A0) of the GDL. Quantitative analyses of these ratios clarify that the concentration over-potential increases with increase in the flooding ratio. Increasing pressure difference between high and low pressure channels for the interdigitated flow beyond the bubble point of the GDL pores enables an increase in current density up to 2 A/cm2 when the utilization of the air is 40%. Such current density has hardly been accomplished by the conventional PEFCs.
|Number of pages||7|
|Journal||Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B|
|Publication status||Published - May 2008|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering