Topology optimization of proton exchange membrane fuel cell flow fields with interface enhancement and morphology-robustness constraints

Conventional density-based topology optimization is mainly driven by global flow and heat-transfer metrics. The fluid–solid interface is usually formed indirectly as the density field evolves, and thin and threshold-sensitive features can remain. To address these issues, an interface-enhanced and morphology-robust topology optimization method is proposed for the cathode flow field of proton exchange membrane fuel cells. In the flow–heat-transfer bi-objective framework, an active-interface enhancement term is constructed by coupling local interface density, a positive temperature-difference driving force, and a velocity-utilization factor. Local heat-transfer conditions can therefore directly influence interface placement. A morphology-robustness constraint is also constructed from the difference between eroded and dilated projections to suppress thin, isolated, and threshold-sensitive features. The interface-enhanced and robust topology-optimized flow field (IERTO-FF) is generated through two-dimensional thermofluid optimization and then reconstructed in three dimensions. It is compared with conventional, parameterized, and other topology-optimized flow fields using a steady, non-isothermal gas–liquid two-phase PEMFC model and 25 cm 2 single-cell experiments. The IERTO-FF exhibits a pressure drop of 79.77 Pa, which is 91.39 % and 64.27 % lower than those of the serpentine and parallel flow fields, respectively. Its average liquid–water concentration is the lowest among the eight flow fields. At 0.5 V, the net power density reaches 0.6866 W/cm 2 , 16.04 % higher than that of the parallel flow field. The proposed method preserves the basic thermofluid performance while producing a clearer and more stable topology. Lower flow loss, improved liquid–water management, and higher electrochemical output are also achieved. The method provides a useful approach for inverse design of PEMFC cathode flow fields.