A multi-resolution simulation method was developed for the polymer electrolyte membrane (PEM) fuel cell simulation: a full 3D model was employed for the membrane and diffusion layer; a 1D+2D model was applied to the catalyst layer, that is, at each location of the fuel cell plate, the governing equations were integrated only in the direction perpendicular to the fuel cell plate; and a quasi-1D model with high numerical efficiency and reasonable accuracy was employed for the flow channels. The simulation accuracy was assessed in terms of the fuel cell polarization curves and membrane Ohmic overpotential. Overall, good agreements between the simulated results and the experimental data were obtained. However, at large current densities, with high relative humidity reactant inputs, the simulation under-predicted the fuel cell performance due to the single-phase assumption; the simulation slightly over-predicted the fuel cell performance for a dry cathode input, possibly due to the nonlinearity of the membrane properties in dehydration case. Further, a parameter study was performed under both fully humidified and relatively dry conditions for the parameters related to the cathode catalyst layer and the gas diffusion layer (GDL). It is found that the effects of liquid water in both the GDL and catalyst layer on the cell performance, and the accurate identification of the cathode catalyst layer parameters such as the cathodic transfer coefficient should be focused for future studies in order to further improve the model accuracy.
Numerical study of the effect of effective diffusivity and permeability of the gas diffusion layer on fuel cell performance
