Study on a purge method using pressure reduction for effective water removal in polymer electrolyte membrane fuel cells

Polymer electrolyte membrane fuel cells are used as a power source in automobiles where they are required endure harsh conditions like sub-zero temperatures. A new purge method is introduced in this study that uses a sudden pressure reduction to minimize residual water in the fuel cell. The internal ohmic resistance and the dew point temperature of the exhaust gas in the cathode were measured to verify the effectiveness of the proposed method. In addition, images of the surface of the microporous layer were obtained using a microscope and cold start experiments were conducted to verify the effectiveness of the method. The results show that most of water on the catalyst layer and the membrane electrolyte assembly was removed following the pressure reduction purge compared to the normal gas blowing purge process. A durability test was also conducted and no significant degradation during the pressure reduction purge process was observed.