Water Transport in Gas Diffusion Layer of PEFC with Wettability Distribution in Thickness Direction

Abstract

To improve the water transport of a gas diffusion layers (GDL) in a polymer electrolyte fuel cell (PEFC), the effect on the wettability distribution in the thickness direction of the GDL was investigated by a lattice Boltzmann method (LBM). Because much water is generally accumulated in the GDL under rib, the water behavior in the GDL under rib was the focus. The result showed the water in the GDL was significantly reduced by the wettability distribution in the thickness direction made by weak and strong hydrophobicity because the water in the lower of GDL was pulled up to the upper of GDL and the water in the upper of GDL was transported into the channel along the weak hydrophobic region. The depth of the weak hydrophobic region from the GDL surface equivalent to about four pores advantageous to reduce the water in the GDL.