Comprehensive three-dimensional model of PEMFC with straight flow channels and cell performance simulation

The purpose of this paper is to investigate the effects on cell performance of gas-diffusion layer thickness, porosity, and the catalyst particle size. A comprehensive three-dimensional multicomponent transport model was developed for a typical unit of Proton Exchange Membrane fuel cell (PEMFC) with straight flow channels. The activation overpotential was obtained locally in the catalyst layer by solving electric potential equations separately for the membrane and solid phase, instead of assuming a constant through the catalyst layer. The electrochemical reaction rate in the catalyst layer was modified by the agglomerate model to account for the effect of diffusion resistance across the catalyst particles. The cell polarization curve is predicted by the model, and it agrees well with the experimental data published. The model is used to investigate the effects of gas-diffusion layer thickness, porosity, and the catalyst particle size. Conclusion are drawn as follow: the cell performance can be enhanced by increasing the porosity of gas-diffusion layer; and the thickness of the gas diffusion should be optimized to fulfill the requirements of the electro-chemical reaction rate and the fuel cell cost. Also the cell performance can be enhanced by educing the catalyst particle size.