Preparation And Properties Of Expanded Graphite-based Composite Bipolar Plates

Bipolar plate is one of the important components of proton exchange membrane fuel cell, which can provide reaction gas channels and isolate the reaction gases from each other along with conducting current. How to reduce the cost of bipolar plate has become the critical issues of fuel cell industry. Composite bipolar plate has the comprehensive advantages of graphite bipolar plate and metal bipolar plate, which has the characteristics of resistant to corrosion, small size, light weight and high strength. Therefore, composite bipolar plate is the main trend of the future.In this paper, expanded graphite was utilized to prepare composite bipolar plate by dry blending with powder resin. The effects of the type and content of resin, the molding temperature and time, the molding pressure and other conditions of release agent were inspected on the properties of composite bipolar plate. Analytical techniques with TG, DSC, SEM, etc., were used to study the conductivity, the bending strength, the density, the hardness and the hydrogen transmission of the composite bipolar plate. Better release agent was gotten after experiments. The composite bipolar plate prepared fits the demand on the property of resin/graphite composite bipolar plate proposed by Department of Energy, USA.By use of expanded graphite as conductive filler, the three-dimensional network structure can play full role in the composite bipolar plate. The melted resin package can be avoided and the fine graphite conductivity, the thermal conductivity and the flexibility of the expanded graphite can be made full use. The use of solvents in the traditional process of wet blending with resin and graphite also can be avoided, and the costs can be reduced. Thus, the environment can be protected. The study lays the foundation of the manufacture of composite bipolar plate in industry.