Development of composite-metal hybrid bipolar plates for PEM fuel cells

In this study, in order to increase the electrical conductivity, a carbon composite-metal hybrid bipolar plate has been developed using pre-forming method followed by a plasma surface treatment. A pre-formed metal foil between the carbon fiber/polymer composite plates promotes the metal foil to follow the shape of the channels of the bipolar plates without tearing and permits a continuous flow of electrons. The pre-formed metal foil also reduces the residual stress between the composite and metal foils, which helps prevent delamination between the composite and metal foils. The composite surface has been treated with plasma to increase the contact area between the carbon fiber and the gas diffusion layer (GDL). The composite-metal hybrid bipolar plates have only 1.4% of the total electrical resistance of that of the conventional composite bipolar plates. Unit cell test results have proved that the developed composite-metal hybrid bipolar plates with reduced total electrical resistance increase the cell performance.