Study on the Effect of Microporous Layer Structure Parameters on the Fingering Process of Liquid Water in the Gas Diffusion Layer of PEMFC

The microporous layer (MPL) plays a crucial role in regulating the water transport process within the gas diffusion layer (GDL) of proton exchange membrane fuel cell (PEMFC). A two‐dimensional GDL model is established, and key parameters such as wettability, intrusion thickness, and porosity of the MPL are systematically analyzed based on the volume of fluid (VOF) method. This study aims to explore its effects on the distribution characteristics of liquid water, breakthrough behavior, and liquid water saturation within the GDL. The results reveal that the nonuniform wettability MPL limited the lateral diffusion of liquid water within the GDL, allowing liquid water to flow along the established path. The liquid water saturation within the GDL is reduced by 12% compared to the uniform wettability. The greater the MPL thickness, the fewer the liquid water breakthrough sites at the interface between the MPL and the macroporous substrate (MPS). There are 15 liquid water breakthrough sites at the interface at a thickness of 5 μm, and at a thickness of 45 μm, the number of breakthrough sites is sharply reduced to 2, and the time for liquid water to break through the interface is reduced by 44.8%.