Development of a Semi-Empirical Model for Description of PEMFC Polarization Curve Based on Effect of Fuel Crossover and Internal Current Through a PEM

Abstract

The manuscript presents a new semi-empirical cell voltage model of performance of PEMFC based on Srinivasan et al’ s model with addition of an extra term to take account the effect of fuel crossover and internal current through membrane using numerical simulations developed under CFD software. This semi empirical model describes the effect of charge and mass transport (O2, H2 and e-) through a PEM such as permeability, solubility, and internal current on polarization curves. The permeability within hydrated Nafion were obtained based on the assumption that the gas solubility and gas diffusivity were determined as the volume averaged value based on the solubility, diffusivity and volume fraction of both water and Nafion phase. The effect of current exchange density on polarization curves was studied. The obtained results show that overpoential can be reduced by using thicker membrane; in addition temperature and water content involve over potential. Indeed, internal currents and fuel crossover increase as temperature, water content increase while OCV decreases with decreasing in current exchange density.