Performance of proton exchange membrane fuel cell with bionic fish scale porous flow field design

A bionic fish-scale porous flow field was proposed and investigated for proton exchange membrane fuel cells (PEMFCs). To enhance cell performance, the effects of varying GDL porosity and downstream contracting flow field dimensions were examined. Results show that compared to parallel/serpentine flow fields, the bionic design significantly optimizes oxygen transport both transversely and longitudinally, while also reducing pressure drop, improving water removal efficiency and thermal management. At 0.2 V, it reduces pressure drop by 44.92 % versus serpentine fields and increases current density by 36.58 % over parallel fields. Peak power density at 0.4 V shows 8.13 % and 27.82 % improvements over serpentine and parallel configurations respectively. Reducing GDL porosity from 0.78 to 0.48 decreases oxygen concentration but increases water concentration, helping maintain membrane humidity to ensure proton conduction. Optimal performance occurs at 0.58 porosity, yielding peak current density (1.8987 A/cm2) and power density (0.5824 W/cm2) – representing 1.61 % and 1.11 % gains over 0.78 porosity. The downstream contracting flow field enhances drainage and oxygen transport with increasing depth at the expense of reduced conductivity and elevated pressure drop. At 0.4 mm depth, peak current density reaches 1.9204 A/cm2 with 13300 Pa pressure drop, delivering performance improvements while requiring increased pumping power.