In Situ Determination of MEA Resistance and Electrode Diffusivity of a Fuel Cell

Abstract

This paper describes a novel method to determine the membrane electrode assembly (MEA) resistance and electrode diffusion (MRED) coefficient for a fuel cell (the MRED method) under in situ conditions. It is shown that the MRED method allows the determination of (i) the ohmic resistance of an MEA and (ii) the mass-transport coefficient of the electrodes. The method is based on the galvanostatic discharge of a fuel cell with interrupted reactant supply. Application of the method to the cathode of a polymer electrolyte membrane fuel cell is demonstrated, and the experimental results are analyzed using a theoretical model based on a simple one-dimensional diffusion process using Fick’s law. Comparison of the experimental O2O2 mass-transport coefficient with theoretical values indicates that diffusion in the active layer is mass-transport limiting.