A FINITE-ELEMENT-BASED PRESSURE ALLOCATION STRATEGY BETWEEN SEALANT AND MEMBRANE ELECTRODE IN PEM FUEL CELL STACKS
Keywords:
Proton exchange membrane fuel cell, Sealant, Membrane electrode assembly, Pressure allocation, Finite element analysisAbstract
Sealing reliability is essential to the safe and efficient operation of proton exchange membrane fuel cell (PEMFC) stacks. In practical stack assembly, however, increasing the seal compression to improve gas tightness may simultaneously raise the mechanical stress in the membrane electrode assembly (MEA), especially in the membrane and gas diffusion layer region. This trade-off makes conventional seal design based solely on leakage prevention insufficient for high-performance stack packaging. In this study, a finite-element-based pressure allocation strategy is developed to coordinate the mechanical requirements of the sealant and the MEA. A two-level modeling framework is adopted. First, a local metal bipolar plate-sealant-MEA frame model is established to verify sealing feasibility and evaluate the force requirement of the seal line under different compression ratios. Then, a refined full model including the flow-field ribs, seal groove, sealant, proton exchange membrane, frame region, and gas diffusion layer is built to investigate the coupling between seal compression, bipolar-plate displacement, and membrane stress. The results show that although a semicircular sealant can satisfy the sealing criterion in the local model, it becomes unsuitable in the full structure because the compression required to ensure gas tightness leads to excessive membrane stress. Under a 20% compression ratio, the maximum equivalent stress in the proton exchange membrane reaches approximately 4.8 MPa, which is far above the desired level of about 1.4 MPa. An improved pressure allocation strategy is therefore proposed by controlling bipolar-plate displacement rather than directly preserving the seal compression state. Based on this strategy, an optimized rectangular sealant section at a compression ratio of 17% achieves both adequate gas tightness and acceptable membrane stress. The study provides a practical finite-element-guided route for coordinated seal and MEA design in PEMFC stacks.References
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