The electrical resistance of flexible graphite as flowfield plate in proton exchange membrane fuel cells

摘要

Flexible graphite can be stamped into gas channels for proton exchange membrane fuel cells attributing to its good conductivity,corrosion resistance and flexibility.However,the electrical resistance of the bipolar plate consisting of a coated metal foil and the stamped flexible graphite flowfield plate should be investigated,for the internal resistance would affect the output power of the fuel cell greatly.The influences of various parameters,such as compacting pressure,temperature,effective area of the coating and the water content of the flexible graphite on the electrical resistance were studied.The electrical resistance decreases with the increment of compacting pressure exponentially.The temperature and the effective area of metal foil coating both have linear relations with the electrical resistance.And the water content of the flexible graphite has a very complex relation with the electrical resistance;it is the most important influencing factor.At last,an empirical equation for the electrical resistance,giving a good fit to the test data,was determined.