Effect of Different Graphite Materials on the Properties of Bipolar Plates Fabricated by Selective Laser Sintering

Selective Laser Sintering (SLS) provides a way to fabricate graphite composite bipolar plates, which significantly reduces time and cost at the research and development stage of bipolar plates, as compared with the conventional fabrication methods of compression molding and injection molding. Different graphite materials (natural graphite, synthetic graphite, carbon black, and carbon fiber) were investigated in the SLS process, the effect of each material on electrical conductivity and flexural strength of bipolar plates was determined. Natural graphite was great for electrical conductivity, Carbon fiber was good for flexural strength, but synthetic graphite and carbon black were not good for both two properties. By proper combination of these materials bipolar plates with electrical conductivity ranging from 120S/cm to 380 S/cm and flexural strength of around 40 MPa can be obtained, which satisfied the requirements set by Department of Energy and also was comparable with those developed by compression molding and injection molding.