Research Of Graphite-base Composite Bipolar Plates Of PEMFC

The polymer electrolyte membrane fuel cells(PEMFC) is one kind of efficient,low-contamination power source.In the future,it has a good prospect applying indriving electrical source,portable electrical source,home power station and etc.Atpresent,the high cost is the most important reason for blocking its commercializat-ion. Bipolar paltes are the critical component which decides the cost of PEMFC.It isimportant to investigate composite of bipolar paltes for its commercialization. Thecomposite of bipolar paltes includes metals,graphite,graphite/resin composite,carbon fiber-graphite/resin composite.And graphite/resin composite,carbon fiber-graphite/resin composite are the important research direction.The paper choosed S-ZD001 PI, S- ZD002 PI, L- ZD002 PI, PAN as bulk addit-ive,graphite as basal body, and CF as reinforcements.The graphite/polymer compositewas prepared by vacuum moulding.On the condition of graphite content＞10％, itinvestigate the way of preparing composite,polymer, inorganic fillers, moulding tem-perature,vacuum condition and CF.Characterizations was getted by measuringelectricresistance,partical size, SEM and mechanical properties.The result showed that,contact resistance occupied great proportion.Particle size of granule graphite wasbigger than that of flake graphite,which caused the resistance of flake graphitecomposite is higher than that of granule graphite on the condition of same graphitecontent. In dry process,the slope of flake graphite content on effect of electricresistance is bigger than that of granule graphite,but in wet process,they were almostthe same. The conductivity of composite with PAN was better than composite withPI.Inorganic fillers did not improve conductivity.When the shaping temperatureincreased,the resistance of composite increased.And the composite with vacuumprocess had less uncontinuou interface,which could form more conduct acess.The composite with CF of gas-liquid oxidation had better conductivity and mechanicalproperties,and composite with CF of gas oxidation had bad result. On the condition ofgraphite content＜10％,it investigated conductivity mechanism. Characterizationswas get by measuring electric resistance,IR,SEM and DMA.The laminated model isalso used simulating the electrical properties of composite material.The result showthat the electrical properties of composite is improved by coupling agent.And Criticalnumber of volumn fraction is 1.43％,when the graphite formed conductive networkfor the first time.The IR and DMA verify that structure ofpolyaniline ischanged.This process reduced the electric resistance up 80~C.And the system ofcomposite coincided the linear relation of conductivity with volumn fraction.