Proton-Exchange Membrane Fuel Cell Ionomer Hydration Model Using Finite Volume Method

In this paper a dynamic membrane electrode assembly water transport model, based on the Finite Volume Method, is presented. First, a state-of-the-art was carried out to collect all the information needed to compute a physical-based model dedicated to fuel cells. Water vapor transport through the multi-gaseous porous media (electrodes) is simulated using Fick, Stattery-Bird, Bruggeman and Knudsen equations. Liquid water transport is considered through capillarity. Membrane water sorption is quantified using a transport flow depending on the equilibrium water content at both sides of the membrane/catalyst layer interfaces. Through the membrane, a mix of diffusion, convection, and electro-osmosis equations is set up. The main novelty relies in the restructuring of all water transport equations into a single implicit equation system, which can iteratively be resolved through LU decomposition. With this method, the model output is represented using easy-to-interpret 3D figures. This new type of display is very useful to investigate the influence of each operating condition on membrane hydration behavior. As the model execution time is quicker than the simulation time, it is also suited for real time simulation on a test station interface. To calibrate and validate this model, mass transfer (flowmeter) and electrical (ohmmeter) methods have been applied