Numerical investigation of the thermal and mechanical response of PEMFCs under coupled loading conditions

Abstract

Thermo-mechanical behavior of proton exchange membrane fuel cells (PEMFCs) subjected to combined clamping torque and thermal loading represents a critical factor governing their electrochemical performance, mechanical durability, and overall operational reliability. A comprehensive three-dimensional finite element model was developed for PEMFCs with four different flow field designs (spiral, serpentine, pin-type, and parallel) to investigate the coupled thermal and mechanical behavior of the cell components. A constant clamping torque of 10 Nm, which represents a typical value applied in practical single-cell assemblies, was imposed, and simu lations were performed across operating temperatures of 50–80 ◦C. The results revealed that the pin-type flow field generated the highest stress levels, while the serpentine configuration exhibited the lowest, leading to approximately 5–6 % lower mechanical stresses and up to 39.2 % lower thermal stresses compared to the pintype design. Directional deformation and stress analyses revealed that the serpentine flow field offers superior mechanical stability compared to the pin-type design, under both clamping and thermal loading conditions. Additionally, the maximum coupled thermo-mechanical stress remained well below the tensile strength limit of the membrane, indicating that the applied assembly conditions ensured safe operation without risk of structural damage. These findings underscore the importance of optimizing flow field geometry to achieve better stress uniformity, enhanced mechanical integrity, and longer service lifetime in PEMFCs. This study presents a novel comparative framework by simultaneously evaluating the thermo-mechanical response of multiple PEMFC flowfield geometries using a coupled finite-element approach, providing critical insights that can guide the optimi zation of thermo-mechanically robust channel designs.