An Analytical Model of the Membrane Electrode Assembly in a PEMFC

An analytical model of the membrane electrode assembly (MEA) in a polymer electrolyte membrane fuel cell (PEM) has been developed for investigating the effect of catalyst layer specifications. Emphasis is placed on the cathode catalyst layer, which is modeled using a finite-thickness formulation with parameters obtained from a variable-width macrohomogeneous model. The variable-width formulation accounts for the effect of changing catalyst layer specifications on the dimensions of the catalyst layer by assuming a constant void fraction. Interest in low-humidity operation of micro-fuel cells that are passively fed ambient air has facilitated the present derivations and assumptions. The model is shown to agree well with experimental data over a substantial range of catalyst layer specifications. In addition, the model shows excellent promise as a tool for optimizing catalyst layers in micro-fuel cells with passive ambient air breathing.