Liquid and oxygen transport in defective bilayer gas diffusion material of proton exchange membrane fuel cell

In this paper, pore network simulations are carried out to explore the effects of micro porous layer (MPL) and its crack location on the liquid and oxygen transport in the gas diffusion material (GDM) of proton exchange membrane fuel cell (PEMFC). The constructed network is composed of cubic pores connected by throats of square cross section. The GDM is partially screened by the land, and the MPL is assumed to have a crack. When the MPL crack is considered under the land in the model, the predicted results agree with experimental findings regarding the effect of MPL on the liquid saturation and distribution in the GDM. This indicates that the liquid may prefer to flow through the MPL crack under the land. The role of MPL in the fuel cell performance is revealed to be dependent on the oxygen effective diffusivity of MPL and GDL. Therefore, caution should be taken before employing the MPL to improve the cell performance. Based on the present studies, some guidelines are gained for the GDM design and optimization.