Three-dimensional numerical simulation of full-scale proton exchange membrane fuel cells at high current densities

Abstract Improving the maximum power density of proton exchange membrane fuel cells (PEMFCs) requires very high current density and downsizing. Challenging targets, such as 0.66 V at 3.8 A/cm2, have been proposed to achieve a power density of 6.0 kW/L. The internal distributions of PEMFCs are not well understood at such densities; they must be analyzed because cell performance and durability relate to distributions such as temperature, the water content of a proton exchange membrane (PEM), and water saturation in gas diffusion layers. We conducted three-dimensional numerical simulations of a full-scale PEMFC and its short stack at high current densities. Model parameters in the simulations were fitted to reproduce experimental results of common PEMFCs. The material properties of the PEM, cathode catalyst layer, and gas diffusion layers (GDLs) were numerically modified to achieve the target power density. Modifying the GDL markedly improved the cell performance. The simulations estimated in- and through-plane distributions at high current densities; results indicate that gas diffusivity and thermal conductivity of GDLs considerably affect the distributions of PEM temperature and water saturation in the GDL, which relate to cell performance and durability.