PEM Fuel Cell Models Validation and Accuracy Analysis

A multi-resolution method is developed for the polymer electrolyte membrane (PEM) fuel cell simulation. A full 3D modeling is employed for membrane and diffusion layer, 1D+2D model is applied to the catalyst layer, that is, at each location of the fuel cell plate, the governing equations are integrated only in the direction perpendicular to the fuel cell plate; and a quasi-1D method with high numerical efficiency and reasonable accuracy is employed for the flow channels. The simulation accuracy was assessed in terms of fuel cell polarization curves and membrane ohmic overpotential. Overall, the agreements between simulated results and experimental data are good. However, at large current densities, when high relative humidity reactant inputs are employed, the simulation under predicts the fuel cell performance due to a single-phase assumption. The method slightly over predicts 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 for a fully humidified cell and a relative dry cell. These parameters include porosity and permeability of gas diffusion layer; porosity, effective oxygen permeability, ratio of thickness of surrounding Nafion layer to exposed agglomerate area density and cathodic transfer coefficient of catalyst layer. Some insight can be obtained by examining their effects on the cell performances in order to further improve the model accuracy.