Modeling analysis for species, pressure, and temperature regulation in proton exchange membrane fuel cells

The performance degradation of proton exchange membrane or polymer electrolyte membrane fuel cell (PEMFC) stems from air starvation and water flooding. In the mathematical modeling, the conservation equations were applied for momentum, mass, species, charge, and energy, to investigate the heat transfer and temperature distribution in the cathode along with the multiphase and multi-species transport under the steady-state condition. This model shows the effect of stoichiometry of reactants and relative humidity on the water saturation. The back-diffusion of water from the cathode to the anode is considered to reduce possible flooding. The feedback controls are used to address the transient water, pressure, and temperature management problems of a PEMFC system. An anode recirculation system measures the feedback signals to regulate the anode and cathode humidities and the pressure difference between the anode and cathode compartments. It was found that the robust nonlinear controller is insensitive to parametric uncertainty, maintaining performance around any equilibrium point.