Research on the Influence of Flow-Guiding Channel Structure on the Output Performance of Proton-Exchange Membrane Fuel Cells

The uneven distribution of reactant gases inside proton-exchange membrane fuel cells (PEMFCs) and insufficient diffusion in the direction perpendicular to the electrode plates are key issues affecting PEMFC performance. In order to enhance the vertical diffusion of the reaction gases, this paper proposes a flow-guiding channel structure and optimizes its structural parameters using computational fluid dynamics (CFD) simulations. A systematic analysis was conducted on the size parameters (leeward-side size A, 1–2 mm; height B, 1–2 mm; minimum-to-maximum cross-sectional ratio κ, 0.3–0.6) and distribution parameters (x-direction spacing L, 0.1–0.7 mm; y-direction spacing H, 2.0–2.6 mm) of the flow-guiding ridges. The results showed that the cell performance is optimal when A=1.5 mm, B=2 mm, κ=0.5, L=0.3 mm, and H=2.2 mm. This structure improves gas distribution uniformity and reduced water accumulation by enhancing gas flow velocities in the x-direction (8–11 mm·s) and z-direction (4–5 mm·s). Compared with the serpentine flow field, the proposed flow-guiding channel structure exhibited a 27% increase in current density at an output voltage of 0.5 V. This study improved the vertical mass transfer capacity of the flow field through the design of the flow-guiding ridges, providing a new solution for optimizing the flow field of PEMFCs.