Effect of graphitization degree of fuel cell gas diffusion layers on their heat management: Modeling and experiments

Serving as gas diffusion layers (GDLs), the thermal conductivity of carbon paper (CP) plays a significant role in the heat transfer management in fuel cells. In the present study, the effect of graphitization degree of CP on its through-plane thermal conductivity and in-plane thermal conductivity is investigated. The relationship between heat treatment temperatures (1800, 2000, 2200, 2400 and 2500 °C) and graphitization degree is also investigated by SEM, XRD and Raman measurements. A model for CP under different graphitization degree is suggested considering the thermal conductivity difference of carbon fiber and matrix carbon. The experimental and simulation results are compared. The results show that the graphitization degree has a significant impact on the through-plane thermal conductivity and in-plane thermal conductivity.