Fabrication and analysis of composite bipolar plates with expanded graphite to increase electrical conductivity of fuel cells

Bipolar plates are one of the most important components in a PEM fuel cell. In this study, a bipolar plate made of stamping method is developed to increase electrical conductivity and mechanical behavior and manufacturing productivity of the fuel cell and to decrease electrical resistance according to DOE. For fabrication these plates, phenolic resins were used as matrix and expanded graphite to increase electrical conductivity and graphite to filler and carbon fiber to increase flexural strength and optimize electrical conductivity. The electrical conductivity increased up to 40 percent respect to the DOE. The flexural strength and impact strength of the measured specimens were improved respect to the DOE about 11 and 170 percent, respectively. The experimental results are in accordance with DOE. According to SEM images and test curves, electric conductivity increases with expanded graphite filler. Finally, the results showed that expanded graphite weight gain did not affect the mechanical behavior of the composite and increased the electrical conductivity.