Effects of Frame Materials and Structures on Stress Concentration of Membrane Electrode Assembly of PEMFCs

A membrane electrode assembly (MEA) is one of the core components of proton exchange membrane fuel cells (PEMFCs) comprising a catalyst coated membrane, gas diffusion electrodes, frames, and seals. By employing a 2D finite element model the mechanical stresses in membrane caused during the cell assembly procedure are analyzed for different MEA frame materials, frame structures and contact behaviors. The stress distributions in the membrane are presented and quantified. A zone with strong nonuniform stresses in the membrane under the end edge of frame/membrane is observed. The stepped frames assembly (SFA) and the bonded contact behaviors have more uniform stress distributions than the aligned frames assembly (AFA) does. The frame materials are not the main factors affecting the stress concentration in membrane for the SFA, while for the AFA the mechanical properties of frame materials should be close to those of the membrane. The results are expected to be helpful for people to select the frame materials and to design frame structures, and can be applied to guide the assembly of PEMFCs.