This study proposes a novel flow-field design strategy that incorporates porous inserts into the bipolar plate (BP) flow channels to address flooding and improve the performance of polymer electrolyte membrane fuel cells (PEMFCs). The BPs were fabricated by maintaining the traditional flow-field structure while varying the number and arrangement of melamine foam inserts, with the electrochemical performance changes analyzed comparatively. The findings revealed that the configuration featuring five porous inserts achieved the highest performance enhancement, with a peak power density increase of approximately 13.4% compared to the conventional cell. This improvement is attributed to localized pressure gradients created by the porous inserts, which facilitated transverse gas transport toward the gas diffusion layer and reduced flooding in the flow channels. However, excessive insertion resulted in increased flow resistance and mass transport limitations, leading to performance degradation. The study also confirmed the impact of insert arrangement on PEMFC performance. Overall, the introduction of porous inserts into BP flow channels, without the need for additional machining processes, offers an effective method for managing water and gas transport in PEMFCs, providing valuable insights for flow-field optimization and the development of high-performance fuel cell systems.
Degradation of proton exchange membrane fuel cells (PEMFCs) can be accelerated by impurities in the air. In maritime environments in particular, sodium chloride (NaCl) can reduce the performance of membrane electrode assembly (MEA) in PEMFCs. In this context, we experimentally analyzed effect of flow channel depth on PEMFCs humidified with a NaCl solution at the cathode side. The analysis was conducted in serpentine flow channels with different depths of 0.4, 0.8, and 1.6 mm. The initial performance of unit cells was compared to their performance after applying a constant current for 10 hours. Results showed that the degradation rate correlated positively with the flow-channel depth. Channel depths of 0.4 and 1.6 mm resulted in 2.4% and 7.3% decreases in the maximum power density, respectively. For the 1.6 mm channel depth, the activation loss after 10 hours was larger than the initial loss.
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