Measurement of in-plane effective thermal conductivity in PEM fuel cell diffusion media

Gas diffusion media used in polymer electrolyte membrane (PEM) fuel cells are highly anisotropic with significantly different transport property values in the through- and in-plane directions. In this study, experimental measurements of the in-plane effective thermal conductivity k for gas diffusion media used in PEM fuel cells have been carried out using a parallel thermal conductance technique. Conductivity values are measured at a mean sample temperature of 70 °C for six different material types and two different orientations in order to quantify the effect of PTFE content on thermal conductivity and to reveal any anisotropic behavior. The results vary from a minimum of k = 3.54 W/(m °C) to a maximum value of 15.1 W/(m °C) for various samples and configurations tested in this study, with an uncertainty between 1% and 2% for all the cases investigated.