Vibration induced multiscale damage mechanism of BPP: From interfacial electron transfer distortion to surface thermal ablation

Surface fretting corrosion of the bipolar plate (BPP) impacts power density, efficiency, and durability of fuel cell. Traditional research focuses on surface coatings, while the significant degeneration of BPP surface due to road vibration is rarely considered. In this paper, a test bench is designed and fabricated to investigate the electrical contact of BPP interface, the contact vibration, current and interface force are regulated respectively, to obtain their impacts on performance degeneration of BPP. Results indicate the BPP surface temperature increases rapidly under 1 Hz vibration, which is close the fuel cell vibration under road operation, while the surface heat increases slowly under high frequency, high interface pressure and lower surface current density. Furthermore, the variation principle of surface contact resistance is analyzed, based on surface erosion characterization. And the erosion evolution mechanism is characterized and deduced. This investigation can provide a theoretical foundation and scientific evidence for inhibiting dynamic damage of the bipolar plate interface.