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 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 the MPL and the catalyst layer (CL) at the cathode side to clarify the effect of the MPL on discharge of produced water. Freezing method was applied to observe the distribution of the condensed water, and the ice distribution on the CL surface was quantified by a binary image processing. The effects of operation conditions on the water distribution were examined, and the distributions were also compared with large amount of ice on the CL surface after -10 degrees C cold start operation. It was shown from these results that the MPL has a role to prevent accumulation of water on the surface of CL and suppress water flooding.