Bipolar plates made of carbon fabric/phenolic composite reinforced with carbon black for PEMFC

Polymer electrolyte membrane fuel cell or proton exchange membrane fuel cell (PEMFC) is composed of bipolar plates, end plates, membrane electrode assemblies (MEAs) and gas diffusion layers (GDLs). Among the constituents of PEMFCs, the bipolar plates are major components, which make up a large portion of the stack volume and cost. In this study, the bipolar plate has been fabricated using carbon fabric/phenolic composite for mass production because the phenolic resin cures much faster than epoxy resin. Because the phenolic resin becomes brittle after being fully cured, it is mixed with carbon black to increase the ductility. The surface of the carbon fabric/phenolic composite bipolar plates has been treated with flame to reduce the interfacial contact resistance. The experimental results show that the contact resistance of the carbon fabric/phenolic composites bipolar plate decreases as the flame-treatment temperature and time increase due to the degree of carbonization of the phenolic resin, while the flexural strength decreases because the carbonization of phenolic resin increases its brittleness. Therefore, the optimum flame surface treatment temperature and processing time for the carbon fabric/phenolic composite bipolar plates are investigated to optimize the electrical conductivities and mechanical properties.