An Experimental Investigation of the Effects of Operating Conditions on Anisotropic Electrical Conductivity in a PEM Fuel Cell

This study aimed to investigate the effects of the operating conditions on the anisotropic electrical conductivity of diffusion layers in a polymer electrolyte membrane fuel cell. For this purpose, two different gas diffusion layers were considered. The electrical conductivity values of the selected gas diffusion layers in both in-plane and through-plane directions were examined experimentally, depending on cell temperature, relative humidity and clamping pressure. Resistance measurements were carried out for all combinations of operating conditions where cell temperature, relative humidity (RH) and clamping pressure were changed from 50 degrees C to 80 degrees C, from 70% to 100% and from 2 bars to 8 bars, respectively. The results showed that although the relative humidity had a dominant effect on the in-plane conductivities for both the gas diffusion layers, it did not significantly affect the through-plane conductivities. The through-plane conductivities increased with the increase of the cell temperature and the clamping pressure, whereas the in-plane conductivities did not remarkable change.