Effect of PEM Fuel Cell Operation on Gas Diffusion Layers and Membrane Stresses

A three-dimensional, multi-phase, non-isothermal computational fluid dynamics model of a proton exchange membrane fuel cell has been developed to investigate the hygro-and thermal stresses in PEM fuel cell, which developed during the cell operation due to the changes of temperature and relative humidity. The behaviour of the gas diffusion layers and membrane during operation of a unit cell has been studied and investigated under real cell operating conditions. The results show that the non-uniform distribution of stresses, caused by the temperature gradient in the cell, induces localized bending stresses, which can contribute to delaminating between the membrane and the gas diffusion layers. These stresses may explain the occurrence of cracks and pinholes in the membrane under steadystate loading during regular cell operation. The results show that the maximum von Mises stress in fuel cell for the low, intermediate and high load conditions were 3 : 1 2, 3 : 1 6, and 3 : 2 3 MPa respectively.