Topology Optimization of Cathode Gas Channel Layout in Proton Exchange Membrane Fuel Cells (PEMFCs)

The output of a proton exchange membrane fuel cell (PEMFC) relies on the transport behavior within the cathode gas channels, which is largely determined by their design features. Current designs remain inadequate, as they often rely on heuristic modifications of existing layouts or designer intuition with suboptimal performance. In this study, topology optimization is proposed to redesign the PEMFC cathode gas channel layout without a priori assumptions. The optimization aims to maximize the reactant concentration and minimize power dissipation along the flow path. A density-based topology optimization framework is adopted and coupled with a gradient-based optimizer. The problem is solved within a three-dimensional half-cell model. For computational tractability, a reduced-order, depth-averaged 2D model is also implemented. The optimized topology yields an enhanced current density with lower energy dissipation over the conventional benchmarks. At an inlet velocity of 0.15 m/s, the pressure drop is reduced by 46.7% compared to the serpentine layout, though it is 28.2% higher than that of the parallel case. Within the optimized channels, oxygen flows at higher local velocities, which allows more homogeneous reactant delivery across the domain. Compared to the serpentine layout, the optimized design increases the mean current density by 20.9% and lowers its standard deviation by 4.9%; relative to the parallel layout, the improvement in the mean current density reaches 39.7%. Placing more emphasis on dissipation minimization during optimization produces more intricate and tortuous channel topologies. Such design flexibility enables the discovery of unconventional yet efficient layouts that can be readily manufactured thanks to additive manufacturing (AM).