A review of microstructure optimization design for flow fields of metallic bipolar plates in hydrogen fuel cells

Abstract

Metallic bipolar plates (BPPs) are critical components in proton exchange membrane fuel cells (PEMFCs), accounting for the majority of stack mass, volume, and cost. The microstructure of the flow field directly governs reactant distribution, water management, and interfacial contact resistance, thereby determining overall cell performance and durability. This review examines recent advances in the optimization of flow field microstructures for metallic BPPs, encompassing conventional channel configurations, bio-inspired and fractal geometries, and topology-optimized architectures. The analysis extends to manufacturing technologies, including stamping, hydroforming, and additive manufacturing, which dictate the geometric fidelity and cost-effectiveness of metallic plates. Furthermore, protective coating strategies—such as diamond-like carbon, nitride films, and metal oxide layers—are discussed in relation to corrosion resistance and electrical conductivity in acidic fuel cell environments. Multiphysics simulation methods that couple fluid dynamics, electrochemical reactions, and structural mechanics are highlighted as essential tools for rationalizing microstructural design. Finally, future research directions are identified, focusing on multi-objective optimization, in situ characterization, and the integration of advanced manufacturing with intelligent design frameworks to accelerate the commercialization of high-performance PEMFC stacks.