Optimization design of proton exchange membrane fuel cells with bio-inspired leaf vein flow channels

The design of bipolar plates stands as one of the most promising research domains in fuel cell development, with flow channel configuration playing a pivotal role in determining the output power of proton exchange membrane fuel cells (PEMFCs). Given the responsibility of bipolar plates in distributing reactants and expelling waste, akin to certain biological structures, this study integrates biomimicry with PEMFC bipolar plate model design, proposing a novel Leaf vein flow channels (LVCHs) structure. By enhancing the transport of oxygen to the electrode surface within the channels, the issue of oxygen deficiency and reactant uniformity in PEMFCs is addressed. Comparative analysis with traditional Serpentine flow channels (SFCHs) was conducted, investigating and analyzing LVCHs' cathode and anode gas concentration distribution, membrane water concentration distribution, proton conductivity distribution, pressure distribution, electro-osmotic drag distribution, counter-diffusion distribution, and electrochemical performance. Results indicate that, under the influence of biomimetic enhancement, LVCHs significantly facilitate oxygen transport to the electrode surface. For instance, at an inlet humidity of 60% for both anode and cathode, the maximum power density achieved with the leaf vein flow field was 0.823536 W/cm², representing an approximately 3% increase compared to the serpentine flow field at 0.8020686 W/cm². Through validation, optimal structural parameters for LVCHs were determined, with a ridge width of 0.6 mm, 20 branches, and channel heights of 0.9/0.6 mm. It is believed that the utilization of this novel channel shape offers a promising solution for flow channel design in PEMFCs.