Chapter 6 – Freeze Damage to Polymer Electrolyte Fuel Cells

Publisher Summary Dozens of studies are performed to examine various aspects of fuel cell material compatibility and performance degradation in freezing environments. The damage resulting from a frozen soak, from freeze/thaw (F/T) cycling, and from frozen start is examined. The purpose of this chapter is to explore the damage resulting from freeze/thaw conditions. Generically, damage resulting from a frozen environmental condition is due to water generated at the cathode during sub-zero operation, or the existence of liquid water that resides in the membrane, porous media after shut-down. An important result from accumulated studies is that, for conventional fuel cell materials and designs, no significant damage is observed from simply cycling the fuel cell material to subzero conditions without start-up operation or liquid water before freeze. Significant damage is observed from simply cycling the fuel cell material to subzero conditions without start-up operation or liquid water before freeze. Although many studies are conducted to investigate freeze damage on different components of a polymer electrolyte fuel cell, there are significant variations in the results. Much of this variation can be ascribed to the non-standardized testing procedures, cell designs, and materials used. There is still a clear need to resolve these discrepancies with fundamental understanding of the physicochemical mechanisms involved, so that optimized designs, materials, and protocols can be developed. This chapter helps to better understand and codify the existing data. Additionally, methods and potential concepts to mitigate freeze-induced damage are discussed.