Through-Plane Thermal Conductivity of PEMFC Porous Transport Layers
We report the through-plane thermal conductivities of the several widely used carbon porous transport layers (PTLs or GDLs) and their thermal contact resistance to an aluminium polarisation plate. We report these values both for wet and dry samples and at different compaction pressures. We show that depending on the type of PTL and possible residual water, the thermal conductivity of the materials varies from 0.15 to 1.6 W K−1 m−1 — one order of magnitude. This behaviour is the same for the contact resistance varying from 0.8 to 11 10−4 m2 K W−1. For dry PTLs the thermal conductivity decreases with increasing PTFE content and increases with residual water. These effects are explained by the behaviour of air, water and PTFE in between the PTL fibres.