Effects of porosity gradient and average pore size in the in-plane direction and disposition of perforations in the gas diffusion layer on the performance of proton exchange membrane fuel cells

Abstract

A gas diffusion layer (GDL) is the primary component of proton exchange membrane fuel cells (PEMFCs) that aid in supplying reactant gases from the flow channel to the catalyst layer. It improves the discharge of water generated by the electrochemical reaction from the catalyst layer to the flow channel. Since the GDL is composed of pores that range from nanometer to micrometer in size, it is susceptible to water flooding. Thus, water discharge capability should be enhanced by increasing the capillary pressure gradient. In this study, the porosity and average pore size of the GDL are varied in the planar direction by varying the gasket thickness in the in-plane direction. Furthermore, the effects of the disposition of perforations in the GDL on PEMFC performance are investigated by forming perforations by mechanical processing. A total of three types of GDLs were fabricated, with the same number of perforations on the inlet, outlet, and the entire area of the GDL. Performance tendencies of the GDL were confirmed in both the porous flow channel mimicking the flow channel currently used in fuel-cell electric vehicles and the serpentine flow channels.