Modeling dynamic behaviors of a single cell proton exchange membrane fuel cell under different operating conditions

The objective of this paper is to investigate transient behaviors of a proton exchange membrane (PEM) fuel cell under different operating conditions by developing a transient model. The fuel cell model includes a mass transport submodel and an equivalent circuit submodel. In the mass transport model, transport phenomena in the flow channel and gas diffusion layer (GDL) on both electrodes and in the membrane were considered as well as the phase change of water in the GDL. Both transient and steady performance of fuel cell was studied under various operating conditions such as different operating temperature, pressure, inlet reactants humidity and gas stoichiometric ratio. The results indicate that the dynamic responses of the PEM fuel cell are mainly affected by diffusion and balance speed of reactants inside the fuel cell. It takes approximately the same time for the cell voltage and hydrogen mass flux to reach steady state after the current jump. The liquid water saturation in the GDL takes longer time. The inlet reactant humidity and gas stoichiometric ratio also have significant impact on the improvement of cell performance. The dynamic responses predicted by the model agree well with the results obtained from experimental investigation.