Numerical optimization of bipolar plates and gas diffusion electrodes for PBI-based PEM fuel cells

This paper is devoted to the numerical optimization of the geometry of some key cell components (flow-field channels, current transfer ribs of bipolar plates, gas diffusion electrodes) of high-temperature PEM fuel cells using H3PO4-doped Poly Benzimidazole (PBI) as solid polymer electrolyte. Some design specifications as well as optimum values of key operating parameters are proposed to increase the efficiency of such fuel cells. For this purpose physicochemical model and corresponding novel effective technique for solving of 2D transport equation have been developed. Results of the numerical analysis of dependence of fuel cell performances upon the geometry of cathodic and anodic flow-field channels, operating temperature and gas diffusion electrode parameters are provided. In particular, it was demonstrated that optimum relative width of current-transfer rib (i.e. the ratio between width of rib divided to sum of widths of rib and channel) is determined mainly by competition between diffusion and current conductivity in a gas diffusion electrode and is approximately equal to 0.30–0.35 for the parameters of cell components used in this study.