The characteristic thickness of polymer electrolyte membrane and the efficiency of fuel cell

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.We propose a simple diffusion model of a PEM fuel cell and perform its thermodynamic analysis. Our description is based on a set of two mass balance equations involving water and proton transport through the membrane coupled with two reaction equations describing the electrochemical reactions at the electrodes. Equations for the water and proton flux densities are constructed in a linearized form suitable for the analysis from the point of view of irreversible thermodynamics. In terms of our simplified model, relations for the characteristic thickness of a PEM membrane is derived, and the maximum efficiency of a fuel cell is evaluated, both as functions of the transport properties of the PEM material.