Modeling of two-phase temperatures in a two-layer porous cathode of polymer electrolyte fuel cells

Abstract

The solid-phase and fluid-phase temperatures inside a two-layer porous cathode of a polymer electrolyte fuel cell are calculated simultaneously. The porous cathode consists of a catalyst layer and a gas diffusion layer. In the gas diffusion layer, a two-equation model is employed to deal with the local thermal non-equilibrium (LTNE) between the solid matrices and the fluids. In the catalyst layer, the energy equation is coupled with species transports via a macroscopic electrochemical model. As for the species transports, the Bruggemann model is employed to describe the effective diffusivities of the oxygen and water vapor in the porous cathode. Results show that fluid-phase temperature and the solid-phase temperature are different due to the LTNE effect. In addition, both the fluid-phase temperature and the solid-phase temperature increase with increasing the electrochemical reaction rate. Finally, the species fluxes and current density inside the catalyst layer and gas diffusion layer are also provided.