Mass transfer enhancement of PEM fuel cells with optimized flow channel dimensions

A comprehensive understanding of gas channel (GC)-gas diffusion layer (GDL) interrelations incorporating the mass transfer coefficients, resistances, and areas provides guidelines for the flow channel design. This paper is based on the “flow field analysis scheme” that combines theoretical analysis and numerical simulation. In the analysis, transport-reaction interactions are clarified using multiple resistances in series approach. Results indicate that the external mass transfer resistance is primarily confined to the GDL; and instead, the GC-GDL interface should be highlighted for a uniform transport flux. It is further revealed that the reconciliation of the mass transfer area and coefficient is the key to enhanced transport capability. On this basis, the analytical solution of optimal channel width is obtained; and its coordination with the flow rate is established. Next, a typical single-channel fuel cell model is investigated with various geometric and operating parameters, further validating and quantifying the theoretical analysis.