The Effects of Morphological and Wetting Properties of Porous Transport Layers on Water Movement in PEM Fuel Cells

A parametric study of the effect of wetting and in proton exchange membrane (PFM) fuel cells morphological properties of the cathode porous transport layer (PTL), also known as the gas diffusion layer (GDL), on water transport in proton exchange membrane (PEM) fuel cells has been conducted using a two-dimensional network model that captures the two-phase capillary flow behavior. The effect of PTL wetting properties is explored by considering four contact angle values. The effect of the morphology is analyzed using six pore size distributions. These six pore size distributions are generated by varying the scale and shape parameters in Weibull probability distribution functions. Also, the effect of a microporous layer (MPL) on water transport in the PTL is considered. Inclusion of the MPL resulted in a significant increase in the percolation pressure and a reduction in the PTL water content due to the formation of a few localized fingers which serve as water conduits. When defects in the MPL were considered, the PTL water content remained low with percolation pressures reduced to values similar to a PTL without an MPL.