A Study On The Graphite/Phenol Formaldehyde Resin Composite Bipolar Plates

Polymer electrolyte membrane fuel cell (PEMFC) is recognized as a new alternative to the present power sources because of its high efficiency, low emission, high energy and power density. Bipolar plate is an important part in FC, which distributes fuel and oxidant for FC and provides electronic connection between single cells. Its cost accounted for about 40% of a FC stack, while the high cost of FC is a key obstacle to its wide application. Therefore, searching materials and manufacturing methods for high performance and low cost bipolar plate has been very important. With the above background, new materials and manufacturing methods for bipolar plates are explored in this study.Graphite/polymer composite plate was manufactured using compression molding with one-step which decreases the processing cost. Compared with injection molding, the compression molding is more applicable for the compound with polymer content in the range of 10~20%. So the composite plates have better electrical properties. Low-cost phenol formaldehyde resin was chosen to mix with natural graphite.The composite plate was manufactured using the compression moulding. The variation of electrical properties, gas tightness, mechanical properties and corrosion resistance with compression technological conditions, polymer content were also studied. The composite plate with formaldehyde resin (PF) content 10wt% can meet the demand for the bipolar plate materials.NG/PF composite plate structure is improved to adapt to wider application. NG/PF composite sandwich plate is invented whose surface layers are made up of coral graphite and its sandwich layer is made up of NG/PF composite. The results show that contact resistance of composite sandwich plate is decreased 3~4 times and the other properties of NG/PF composite plate are not changed.To improve work efficiency uncured composite sandwich plate is studied elementarily and its flaws are found. Prior work is completed for our ideas.