Characteristics and Preparation of Polymer/Graphite Composite Bipolar Plate for PEM Fuel Cells

Abstract

A novel concept of composite bipolar plate composed of modified phenolic resin, graphite, and carbon black with thickness less than 2mm has been successfully prepared by the bulk molding process at ambient temperature. This study investigates a potential approach to improve the properties of composite bipolar plate by choosing appropriate graphite particle size distributions and carbon black added means. The effects of resin content, molding pressure, curing temperature, graphite particle size distribution, graphite sorts, and carbon black on the properties of composite bipolar plate have been studied. The optimum processing conditions for preparing composite bipolar plate are: resin content 15—20wt%; molding pressure 10—12MPa; curing temperature 180°C; graphite particle size distribution -200/+325 mesh; carbon black content 4—5 wt%; and carbon black initially dispersed in resin with supersonic purifier. Under optimum conditions, we have produced composite bipolar plate with electrical conductivity higher than 80 S/cm and flexural strength higher than 40 MPa. In addition, this composite bipolar plate was thermally stable from room temperature to 420°C.