Proton exchange membrane fuel cells rely on precise engineering of internal interfaces to achieve efficient hydrogen-to-electricity conversion. This research quantifies how mechanical assembly pressure and metal-foam flow-field geometry directly influence cell performance through effects on membrane-electrode contact, gas distribution, and water removal.
The study used a 4-square-centimeter single-cell PEMFC operating at 80°C to measure performance across varying humidity levels and compression states. Electrochemical impedance spectroscopy revealed how ohmic resistance and mass-transport losses changed with compression and humidity. Complementary computational fluid dynamics simulations using ANSYS Fluent modeled reactant transport through nickel-foam structures with porosity ranging from 50% to 90% void space.
Results showed that optimized mechanical compression increased power output by approximately 19.5% compared to uncompressed assemblies. Computational models predicted that reducing foam porosity from 90% to 60% void space increased current density by 18.8%, from 1.47 to 1.74 amperes per square centimeter. However, direct unprotected contact between foam and the polymer membrane caused physical damage and hydrogen-oxygen crossover—a critical failure mode in fuel-cell systems.
The research reveals a design tension: higher compression improves electrochemical performance but risks membrane damage if not carefully controlled. Nickel-foam flow fields offer excellent corrosion resistance and thermal properties compared to graphite alternatives, but require protective surface treatments and precisely engineered gasket heights to prevent mechanical damage.
The findings emphasize that assembly pressure, foam porosity, and surface protection must be treated as coupled variables rather than independent design choices. Engineers cannot optimize compression in isolation without considering foam structure and membrane vulnerability. Before nickel-foam flow fields are adopted in commercial fuel-cell stacks, manufacturers must validate designs through both simulation and hardware testing, ensuring that laboratory-scale improvements translate reliably to multi-cell systems operating under variable load, temperature, and humidity conditions.
