A working model of polymer electrolyte fuel cells - Comparisons between theory and experiments

To describe the performance curves of a polymer electrolyte membrane fuel cell we present a Bernardi-Verbrugge-like model. The model contains an improved description of the cathode diffusion and reactive regions. This improvement was motivated by the need to correct the behavior of the Bernardi-Verbrugge model at high cell current densities, where concentration overpotentials and flooding phenomena start to appear. To achieve this goal, we derived a new expression for the overpotential of the cathode reactive region. The advantage of having such an expression is twofold: (i) elimination of strong nonlinearities in the solution scheme (with the result of having a fast and stable numerical code), and (ii) clear inclusion of concentration and flooding phenomena. Extensive applications of the model are presented. The comparison between the results of our simulations and experimental data show astonishingly good agreements. (C) 2002 The Electrochemical Society.