A cell voltage equation for an intermediate temperature proton exchange membrane fuel cell

A zero dimensional isothermal model equation for a single Intermediate Temperature Fuel Cell is developed and expressed as a semi-empirical relationship for cell potential as a function of current density. The model is applicable to fuel cells in which reactants and water product are in the gaseous or vapour phase. The model considers the influence of electrode kinetics using the Butler Volmer equation, over the complete voltage range, Ohmic potential losses and the effect of mass transport through electrolyte films covering catalyst layers on kinetics and thermodynamics. The model is used to simulate the variation in polarisation behaviour of a hydrogen fuel cell using a phosphoric acid doped PBI membrane. Performance predictions using published parameters for electrode kinetics, thermodynamics, conductivity and mass transport are compared with data from a laboratory fuel cell. Agreement between the model predictions and experimental data are good and indicate the relatively simple cell voltage model equation is suitable for estimating fuel cell voltage and power performance.