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We report the through-plane thermal conductivities of the several widely used carbon porous transport layers (PTLs) and their thermal contact resistance to an aluminum polarization 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 the existence of residual water, the thermal conductivity of the materials varies from 0.15 W K−1 m−1 to 1.6 W K−1 m−1, one order of magnitude. This behavior is the same for the contact resistance varying from 0.8 m2 K W−1 to 11×10−4 m2 K W−1. For dry PTLs, the thermal conductivity decreases with increasing polytetrafluorethylene (PTFE) content and increases with residual water. These effects are explained by the behavior of air, water, and PTFE in between the PTL fibers. It is also found that Toray papers of differing thickness exhibit different thermal conductivities.

In this paper we report the thermal conductivity for several battery components. Materials were obtained from several electrode-and separator suppliers, and some were extracted from commercial batteries.

Ion-exchange equilibria of ammonium between an aqueous phase and Nafion 117 were measured at 10, 25, 40, and 60°C by equilibrating the membrane in 0.1 M chloride electrolytes of known cation composition. The water content in the membrane phase decreased linearly with increasing cation fraction of ammonium in the membrane phase (y NH 4 ϩ) from H 2 O ϭ 21.2 ͑moles of water per mole-sulfonic acid groups͒ in proton form Nafion in pure water to H 2 O ϭ 13.2 in ammonium form Nafion in a 0.1 M chloride solution. The conductivity was measured by ac impedance in a two-electrode setup using a stack of membranes. The conductivity also decreased linearly with increasing y NH 4 ϩ from 97 to 25 mS/cm at 25.0°C. Our results indicated that the conductivity of Nafion was isotropic, however, available literature is not conclusive on this matter. The temperature dependence of the conductivity was measured, and the fitted activation energy in an Arrhenius-type equation was found to depend on membrane composition and hence water content.