A Woodpecker-Inspired\nAssembly Methodology for a Proton\nExchange Membrane Fuel Cell with Uniform Contact Pressure on the Bipolar\nPlate

The contact pressure between bipolar plates in proton\nexchange\nmembrane fuel cells (PEMFCs) is nonlinearly distributed, because of\nthe bolt assembly. This nonlinearity in the contact pressure distribution\ncan be amplified under vibration, and the convex point on the rough\nsurface of a membrane electrode assembly (MEA) is equivalent to a\nHertz contact. Under the friction effect, a transient current is generated\nand the bipolar plate corrodes suddenly, resulting in hydrogen and\noxygen leakage. This study proposes a woodpecker inspired assembly\nPEMFC based on a hyoid-shaped wave spring (WIA-PEMFC), to achieve\nuniform contact pressure on the bipolar plates under both static and\ndynamic conditions. Then, the effectiveness of WIA-PEMFC was verified\nvia finite element simulations and experiments. Compared with that\nof conventional assembly methods, the nonuniformity of the contact\npressure can be reduced by up to 60%. Additionally, the electrical\nperformance of WIA-PEMFC was also tested, and the results revealed\na significant improvement in the electrical performance. Moreover,\nWIA-PEMFCs boast high reliability, low cost, and zero emissions due\nto the lack of energy supply equipment, which can facilitate the engineering\ndevelopment of PEMFC stacks with high reliability and high efficiency.