Bipolar Plate Durability and Challenges

Bipolar plates constitute the backbone of a hydrogen fuel cell power stack as they isolate the individual cells, conduct current between cells, facilitate water and thermal management through the cell, and provide conduits for reactant gases as well as removing reaction products. Polymer electrolyte membrane (PEM) fuel cell commercialization and market penetration necessitate the mass production of bipolar plates and are therefore, required to be made of length of their lifetime in combating corrosion, while maintaining low interfacial contact resistance (ICR) and not large supplies of fuel cell materials and high volume manufacturing processes must be reduced for PEM to reach economic viability, to allow it to penetrate the energy market and compete with other systems. The durability of the PEM fuel cell is another important parameter that must be improved to enhance the reliability of the two main components, namely, bipolar plates and MEA. Further research and development must be conducted to rectify the four main bipolar plate corrosion mechanisms namely, corrosion failure by pin hole formation, electrocatalyst poisoning, membrane ion exchange with metal ion, and passivation formation. The concept of replacing graphite with metallic bipolar plates seems promising. This chapter provides an update on the research that can help attain a balance between metal and graphite suitability for PEM fuel cell applications. As more research is conducted to enable metals to perform well under fuel cell operating conditions, an ideal fuel cell system will emerge that can be deployed in the transportation sector.