Investigation of the Effective Transport Properties of Gas Diffusion Layer on PEM fuel cell

Fundamental understanding of the transport properties in gas diffusion layers (GDLs) is a critical issue for the optimal design of polymer electrolyte membrane (PEM) fuel cell. The utilization of the Bruggeman correlation, the Leverett-J function and the Wyllie's model in the description of the gaseous effective diffusivity, capillary characteristics and liquid water relative permeability in GDLs has been doubted in accurately estimating the effective diffusivities of the GDLs. In this study, a three-dimensional, two-phase flow PEM fuel cell model was developed to investigate how this inaccuracy is reflected on the fuel cell performance. The numerical results show that the gas diffusion and liquid water transport in GDLs are strongly determined by the effective diffusivities, which are closely correlated with the cell performance. The gas diffusion exhibits a more significant effect on the cell performance than the liquid water transport and water relative permeability. The water relative permeability is the dominant factor in determining the liquid water transport compared with the capillary characteristics.