PARAMETRIC MODELING OF THE PERFORMANCE OF A 5-KW PROTON-EXCHANGE MEMBRANE FUEL-CELL STACK

A parametric model predicting the performance of a solid polymer electrolyte, proton-exchange membrane fuel cell has been developed using a combination of mechanistic and empirical modelling techniques. Mass-transport properties, thermodynamic equilibrium potentials, activation overvoltages, and internal resistance were defined by fundamental relations. But the mechanistic model, however, could not completely model fuel cell performance, since several simplifying approximations had been used to facilitate model development. Additionally, certain properties likely to be observed in operational fuel cells, such as thermal gradients, have not been considered. Nonetheless, the insights gained from the mechanistic assessment of fuel cell processes were found to give the resulting empirical model a firmer theoretical basis than many of the models presently available in the literature. Correlation of the empirical model to actual experimental data was very good. The performance of a Ballard Mark V 35-cell stack, using a Nafion(TM) electrolyte membrane, and operating on inlet feeds of air (150% excess) and hydrogen (15% excess) has been modelled parametrically, based on a model previously developed for a Ballard Mark IV single cell.