A Two-Phase, Transient Model for the Cathode of a PEMFC Using Thin Film-Agglomerate Approach

This study presents a transient, one-dimensional, and two phase model of the proton exchange membrane fuel cell cathode. A thin film-agglomerate approach is applied to the catalyst layer. The model includes the transport of gaseous species, liquid water, proton, and electrochemical kinetics. The effect of water flooding both in the gas diffusion layer and catalyst layer in the cathode are investigated. The effects of agglomerate radius and the catalyst layer thickness on the overall cell performance are also investigated. The results show that the time for fuel cells to reach the steady state is in the order of 10 sec due to the effect of water accumulated both in the porous layer and the membrane. However the time for proton transport is in the order of 0.1 sec. In addition, before the ionic potential reaches the steady state, it would get a critical value. The critical value would depend on the operating cell voltage. There seems to be an optimum in the catalyst layer thickness and agglomerate radius.