Modeling two-phase behavior in PEFCs

A model is developed to examine quantitatively the effects of flooding on the operation of polymer-electrolyte fuel cells (PEFCs). Specifically, the change in the maximum power as a function of the structural properties of the diffusion media, including the bulk porosity, wettability, thickness, and pore-size distribution, is described. The porous-medium model developed includes analytic expressions and a modeling methodology for handling both liquid and gas flow. The model is used in combination with our previous membrane model to simulate transport in typical gas diffusion layers and examine the effect of layer hydrophobicity on the maximum power. (C) 2004 The Electrochemical Society.