Role of Micro-Porous Layer for Water Transfer Phenomena in PEFC

Micro-porous layers (MPLs) play an important role in the water management of polymer electrolyte membrane fuel cells (PEFCs), but details of the mechanism to suppress water flooding has not been fully understood. In this study, we investigated water distribution at the interface between MPL and catalyst layer (CL) at the cathode side to clarify the effect of MPL on discharge of produced water. Freezing method was applied to observe the distribution of the condensed water, and the distribution of ice on the CL surface was quantified by a binary image processing. In addition, comparing normal operation with start-up temperature -10○C, there is large amount of condensed water on the CL surface after operation at -10○C. Based on these results, the MPL has a role to prevent accumulation of water on the surface of CL, and suppresses water flooding.