Performance of PBF‐Printed Micro‐Channel Bipolar Plates as a Function of Flow‐Field Parameters and Plane Area

ABSTRACT SUS 316L bipolar plates (BPPs) with rectangular micro‐channels for polymer electrolyte membrane fuel cell (PEMFC) were fabricated using powder bed fusion (PBF) technology, and the effects of flow‐field structure parameters (channel width, rib width, and channel depth) on fuel cell performance were analyzed. While PBF effectively realized complex micro‐geometries, surface roughness and minor deviations such as rib fillets and pores were observed. Fuel cell performance evaluation results revealed a clear positive correlation where reducing rib width expanded the plane area, increasing current density by approximately one‐third of the area expansion ratio. Notably, although the plane area of the BPP with 400 µm channel and 200 µm rib widths was 33.2% larger (1508 vs. 1132 cm −2 ) than the reference BPP (500/500 µm), the resulting current density was disproportionately higher at 48.2% (1.132 vs. 0.764 A cm −2 ). Regarding channel depth, optimal performance occurred at 600 µm, with a decline at 700 µm. These findings demonstrate that while channel dimensions are independent variables, their combined impact is effectively represented by the plane area. Consequently, prioritizing plane area expansion is suggested as a significant design consideration for enhancing the performance of micro‐channel BPPs.