Effects of operating relative humidity on the water transport and distribution of PEMFC with steady-state model

A two-dimensional, steady-state, two-phase model for a PEM fuel cell (PEMFC) is developed to investigate the effects of operating relative humidity on water transport in the fuel cell. In the model, momentum conservation, mass transportation, charge balance, chemical reaction in the catalyst layers, as well as water condensation in the gas diffusion layers (GDLs) are considered. By modeling and analyzing the water distribution and transportation in the fuel cell, the simulation results indicate that the inlet gas in both anode and cathode should be humidified to keep the membrane from drying, and make it has good conductibility. The PEMFC would have a better performance with 75% relative humidity in cathode inlet. Dry gas in anode side deteriorates the performance of PEMFC much more than that in cathode side.