Effect of Porosity Distribution of Gas Diffusion Layer on Performance of Proton Exchange Membrane Fuel Cells

Abstract

The gas diffusion layer (GDL) is an important and integral part of the proton exchange membrane(PEM) fuel cell. The porosity of the GDL is not uniform due to the compression by the shoulder of the bipolar plate and the accumulation of water produced on the cathode side. In this study, the GDL porosity variation due to both compression and water production is investigated. Four types of porosity distributions are investigated. Using a 2D isothermal single phase PEMFC model, the simulation results under various porosity distributions are compared with the experimental data. The results show that the compression by shoulders affects the local current density distribution, especially under the shoulder of bipolar plates, and the water accumulation affects the local current density distribution along the electrode. The porosity distribution which considers both compression and water accumulation effects is shown to provide a better prediction of the cell performance.