Thermal Contact Resistance Measurements of Gas Diffusion Layers in Polymer Electrolyte Fuel Cells

Localized temperature gradients in a polymer electrolyte fuel cell are known to decrease the durability of the polymer membrane. The most important factor in controlling these temperature gradients is the thermal contact resistance at the interface of the gas diffusion layer and the bipolar plate. Here we present thermal contact resistance measurements of carbon paper and carbon cloth gas diffusion layers over a pressure range of 0.7–14.5 MPa. Contact resistances are highly dependent upon the clamping pressure applied to a fuel cell, and in the present work, contact resistances vary from 3.5E−4 to 2.0E−5 m²K/W, decreasing non-linearly over the pressure range for each material tested. The data presented here also shows that the thermal resistance of the sample is negligible in comparison to the thermal contact resistance. Thermal uniformity in a fuel cell is desirable, and the measurements presented here can be used to more accurately predict temperature distribution in a polymer electrolyte fuel cell.