| Fuel cell (FC) is recognized as a new alternative to the present power sourcesbecause of its high efficiency, low emission, high energy and power density. Bipolarplate is an important part in FC, which distributes fuel and oxidant for FC andprovides electronic connection between single cells. Its cost accounted for about40% 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 andlow cost bipolar plate has been very important. With the above background, newmaterials and manufacturing methods for bipolar plates are explored in this study. The performance of bipolar plates is evaluated in view of their electronicconductivity and H2 permeability. The study began with technological conditionresearch and the effect of mixing method, hot pressing conditions and coolingmethods on the plate's performance was investigated. Then the effect of resincontent, resin type, their melt flow index and grain size of the graphite on the plate'sperformance was investigated. It is discovered that the resin's fluidity and the contactresistance of the graphite grain are two important factors that greatly influence theplate's conductivity while the permeability is highly influenced by the plate'sporosity. In addition, the plates were tested under normal current density that a fuelcell can possibly reach, to make sure the conductivity of the composite plates stableunder fuel cell environment. Encouraging results are achieved in regards that the proposed naturalgraphite/resin composite plate will be suitable for FC and their cost can be highlydecreased by the method of one-step press molding. The PP-NG and PVDF-NGplates produced by this way, with the potential of much lower cost compared withconventional bipolar plate of hard graphite, meet the requirement of PEM fuel cellwhen the resin content is 8wt%-25wt% and 13wt%-34wt% respectively. These willhelp to make fuel cell more economically competitive.
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