Comparative study of different topological flow fields in PEMWE based on coupled electrochemical and thermal mechanisms

High-current PEMWE operation is limited by coupled mass transport and thermal management. A 3D multiphysics model incorporating two-phase flow, non-isothermal kinetics, and heat/mass transfer is developed to evaluate six flow-field designs. Results reveal intrinsic trade-offs between polarization and thermal uniformity. The conventional Parallel Flow Field (PFF) exhibits severe reactant starvation and flow maldistribution, yielding the lowest current density (1.01 A/cm2 at 2.2 V) and high thermal runaway risk (membrane temperature SD = 0.765). In contrast, Symmetrical-Serpentine (SSFF) and Parallel-Serpentine (PSFF) configurations, featuring biomimetic fractal or symmetric structures, actively disrupt boundary layers, enhancing fluid uniformity and reducing ohmic losses, achieving 1.44 and 1.69 A/cm2, respectively. The work generalizes three thermal behavior modes—localized hotspot, gradient, and uniform dissipation. SSFF and PSFF operate in the uniform mode, with temperature SD reduced to 0.446 and 0.450, eliminating local thermal concentrations. This study provides a theoretical basis and optimal topological strategies for thermally robust, high-performance PEMWE.