Tuesday, 11 October 2022
Electrically conductive polymer composites offer the potential for manufacturing lightweight, low-cost, fuel cell bipolar plates. In this work, we explore 3D printing and injection molding of these composites. The primary objective of this research is to fabricate polymer composites that will meet the United States Department of Energy technical target for bipolar plate electrical conductivity (> 100 S/cm). Samples were 3D printed with various filaments, in various printing orientations, and injection molded samples utilized various weight percentages of conductive filler. Sample compositions were then compared by measuring electrical conductivity using a four-point probe method. Conductivities greater than 250 S/cm were achieved, exceeding the DOE technical target. In addition to experimental efforts, we also develop a micromechanical model to predict conductivity based upon direction in the material, fiber alignment, fiber length and diameter, fiber concentration, and fiber conductivity. Modeling predictions show good correlation within 10% of experimental conductivity data.