Study on Gas Diffusion Layer Structure Tolerant to Flooding in PEFC by Scale Model Experiment and LBM Simulation

Abstract

In a polymer electrolyte fuel cell (PEFC), it is important to control water drainage to supply oxygen smoothly to the catalyst layer (CL). Gas diffusion layer (GDL) plays an important role for the water management and it is significant to develop GDL’s that achieves ideal water transport. In this paper, as first step to develop the optimal GDL, the water transport in GDL’s with oriented fiber distribution and with periodic hydrophobic-hydrophilic pattern was investigated. Analysis was made by the lattice Boltzmann method (LBM) and the scale model experiment satisfying similarity conditions for the flow in GDL. In the oriented GDL, the water under rib was drained to the channel smoothly along with oriented fibers placed perpendicular to the rib. In the GDL with hydrophobic-hydrophilic pattern, the water was transported to the channel along hydrophilic band. In this case the hydrophilic region was saturated, while hydrophobic region was left water free.