Electrical conductivity study of graphite composite bipolar plates

Abstract

Graphite composite bipolar plate is one of the core components of the fuel cell, which is mainly composed of graphite and polymer resin, and its electrical conductivity is greatly related to the ratio and distribution of these two materials. In order to study the electrical conductivity of graphite composite bipolar plates, the surface layer of the sample was removed by manual micro-grinding and the distribution law of polymer resin and graphite was investigated by resistance measurement using a through-plane resistance meter. RESULTS: Sample 1 was milled from 1 mm to 0.2 mm in thickness, and the resistance decreased sharply from 0.97 mΩ to 0.51 mΩ when the thickness was milled from 1 mm to 0.9 mm, while the resistance jumped between 0.42 mΩ and 0.57 mΩ when milled from 0.9 mm to 0.2 mm. Sample 2 was milled from 1mm to 0.76mm in thickness and the resistance jumped from 0.93mΩ to 0.48mΩ when the thickness was milled from 1mm to 0.94mm, whereas the resistance jumped between 0.38mΩ and 0.51mΩ when Sample 2 was milled from 0.94mm to 0.76mm. CONCLUSION: By measuring the resistance values of sample 1 and sample 2 after grinding and comparing them, it is known that the thickness of the resin on the surface layer of the sample is about 0.06mm,because of the high content of resin, which leads to the high resistance of the surface layer, and the high content of graphite inside the sample, which leads to the small resistance. This paper provides some research value for improving the electrical conductivity of the surface layer of graphite composite bipolar plates.