Understanding Polymer-Electrolyte-Fuel-Cell Gas-Diffusion Layers
Abstract:
It is well known that for polymer-electrolyte fuel cells (PEFCs) operating below 100°C, water management is a critical issue. If there is too much water, then the catalyst and gas-diffusion layers will become saturated with liquid water and flood; if there is too little, then the membrane becomes highly resistive. In terms of flooding, the liquid water will block the access of oxygen to the reaction sites. In addition, a heat-pipe effect causes an outward flux of water vapor that also inhibits oxygen from reaching the catalyst layers. Key in controlling water management is the impact of the gas-diffusion layers, especially on the cathode side of the cell. Within these layers, two-phase flow dominates. In this talk, I will examine our mathematical modeling approach to gas-diffusion layers with an emphasis on understanding how thermal and water management impact the overall cell performance. I will discuss material solutions such as the use of microporous layers, operating condition impacts such as that of the heat-pipe effect, and end with looking at a mathematical method to account for the influence of the flowfield and its impact on transport in the gas-diffusion layers.
Applied Mathematics Seminar