Modeling PEFC Anode Performance to Include Effects of CO, Reformate Gas, and High Hydrogen Utilization
T. E. Springer
Los Alamos National Laboratory, US
Keywords: PEM Fuel Cell
We discuss a polymer electrolyte fuel cell (PEFC) model designed to calculate anode potential losses from effects of CO poisoning, of H2 dilution in reformate gas, and of hydrogen utilization up to 90% along the flow channel. We specify a cell voltage, a cathode/membrane voltage-current relation, and an anode reactant gas concentration at the flow-channel / gas-diffusion layer interface. Then one-dimensional equations simultaneously describe anode gas fluxes and concentrations through the anode gas diffusion layer and local potential and reactant concentrations in the catalyst layer and determine local current density. These equations are repetitively applied along the flow channel where local reactant utilization rather than position tracks progress until the desired utilization is achieved at the flow channel exit. We will discuss the improvement in solution robustness by adding additional difference equations to pass current density from the cathode to the anode gas diffusion layer, the introduction of CO coverage-dependent rate constants to the anode kinetic equations to reproduce measured data, and the advantage of using local utilization in the flow channel.
NSTI Nanotech 2003 Conference Technical Program Abstract