Experimental Determination of Water Transport in Polymer Electrolyte Membrane Fuel Cells

Abstract

The water crossover flux in polymer electrolyte membrane (PEM) fuel cells was measured using a novel in situ measurement device designed to achieve an accuracy of better than 0.01 in water crossover factor by Sauriol et al. [ J. Fuel Cell Sci. Technol. 6 , 041014 (2009)] . The average anode-to-cathode water crossover flux was linear with respect to current density, suggesting a constant distribution of generated water through anode and cathode channels under the conditions studied. Varying the inlet relative humidity difference between anode and cathode for a given temperature and pressure shifted the water crossover flux–current density line vertically, whereas an increase in cathode pressure changed its slope. The experimental results were used to estimate parameters in the model by Berg et al. [ J. Electrochem. Soc. 151 , A341 (2004)] . If the current density was used as the only fitting criteria, only poor agreement was observed between the measured and calculated water crossover flux. When both current density and water crossover flux were used in the fitting process, the trends in the fitted kinetic and transport model parameters were more consistent, and a good compromise in fitting both polarization and water crossover flux data was obtained. The results highlight the importance of using additional validation data to increase confidence in fitting parameters used for performance prediction of PEM fuel cells.