Development of fiber reinforced compound bipolar foils for fuel cells

Abstract

In the research project "InduRex", the challenge was to produce graphite polymer bipolar plates with the thinnest possible thickness. The physical and chemical requirements were defined according to the values set by the "Department of Energy". Within the scope of the project, the continuous production of highly filled foils, which were then successfully structured as bipolar foils and operated in a fuel cell, was successfully implemented. Initial cell tests demonstrated a good cell efficiency at low and medium current densities. For this reason, the approach of creating bipolar plates from compound foils is still being pursued. Now the challenge is to produce bipolar films with a larger active area and to increase the mechanical stability to such an extent that the construction of a multicell stack can be realized. As a result, a metallic bipolar plate design was successfully transferred to a compound foil as part of the "InduRex" project. The problem is that with a larger bipolar foil there is a risk of obtaining low mechanical stability. Therefore, carbon fibers are introduced into the films as part of the research project "Faserverstaerkte Folien" in order to improve the mechanical properties. In addition to continuous production, the thin-walled foils are reinforced with carbon fibers using a hot press. The fiber-reinforced foils will be characterized in the next steps to investigate the influence of the carbon fibers. The aim is to obtain even thinner bipolar plates with consistent properties from the extruded foils in order to reduce the overall weight and volume of the fuel cell.