Numerical simulation of the stress distribution of the components in a single PEM fuel cell

A typical proton exchange membrane (PEM) fuel cell consists of end plates, current collectors, flow field channel plates, gaskets, gas diffusion layers (GDLs) and a membrane electrode assembly (MEA). The components are stacked together by several bolts applied with specific clamping torques. Consequently, the components are subjected to mechanical stresses which directly affect not only the sealing but also the electrochemical performance of the PEM fuel cell during the long-term operation. Therefore, it is very important to understand the stress distribution of the components in the PEM fuel cell during operation or standby. In this paper, a single PEM fuel cell was assembled by eight bolts applied with various clamping torques ranging from 3.5 to 6.5 N.m. The pressures inside the fuel cell were measured using pressure sensitive films. And the relationship between the clamping torque and the internal compressive pressure was established experimentally. The finite element method (FEM) was used to investigate the stress distribution for each component in the fuel cell. A two-dimensional model which contains the bipolar plate, GDL, and the membrane was studied. Stress distribution in each component of the PEM fuel cell was simulated. In addition, the effect of the clamping torques on the porosity of the GDL was analyzed using FEM. The results are beneficial for revealing the assembly mechanism of PEM fuel cell and can be used to guide its assembly process. It may also be useful in optimal design of fuel cells.