A synchronous investigation of the degradation of metallic bipolar plates in real and simulated environments of polymer electrolyte membrane fuel cells

Abstract

We propose a method to investigate the degradation of metallic bipolar plates (BPPs) synchronously in real and simulated environments of PEM fuel cells. In order to eliminate the uncertainty factor of cell performance resulting from the degradation of the polymer membrane, a simulated PEMFC environment separated from the cell system was created, and the results from real and simulated environments can be directly compared. All of the BPPs aged in real operation and in a simulated environment are used to assemble single cells with the same fabricating and activating conditions. Based on the fitting results for the polarization curves of single cells, the cell ohmic resistance (R) shows a tendency to linearly increase with time, and the increasing rate in the simulated environment is higher than that in real operation. Moreover, the surface morphologies and corrosion behaviors of the BPPs having undergone real or simulated tests are examined. The results indicate that the simulated environment causes more severe degradation of BPPs than the real situation. Therefore, the temporal evolution in the surface conductivity of BPPs is also explored, to evaluate the effect of interfacial contact resistance on the degradation of cell performance. This study can provide a reference method for the preliminary evaluation and design of metallic BPPs.