Technique for Measuring Gas Transport Resistance in Application-Scale Aged Fuel Cell Gas Diffusion Media

摘要

A technique for measuring the gas transport resistance of fuel cells is described that enables this analysis to be performed on application-scale parts including those that have been aged in full scale stacks. The general procedure is to measure the limiting current of a portion of the active area using a current distribution tool at several different values of RH (relative humidity) and oxygen concentrations. Probing just a small portion of the cell's active area enables one to achieve highly differential flow conditions locally, thereby ensuring uniform conditions. This method is applied to a set of new and aged soft goods to illustrate the efficacy of the technique. By comparing the transport resistance of the new and aged parts at different operating conditions, it is shown that the ability of the soft goods to reject liquid water diminished, while the purely gas phase transport resistance is unchanged.