Life extension of PEM fuel cell using startup method

摘要

A fuel cell system that employs a technique for reducing or significantly eliminating the MEA degradation that occurs as a result of the hydrogen-air front in the anode flow channels at system start-up. After system shut-down, any hydrogen remaining within the anode flow channels will be quickly reacted or diffused. At the next start-up, a switch is closed to provide a dead short across the positive and negative terminals of the fuel cell stack as hydrogen is being introduced into the anode flow channels. The existing air in the cathode flow channels reacts with the hydrogen being introduced across the membrane in the normal fuel cell reaction. However, the short prevents a voltage potential across the membrane.

主权项

1. A fuel cell system comprising:
a fuel cell stack including an anode side, a cathode side, a positive terminal and a negative terminal, said fuel cell stack further including a shorting line electrically coupled to the positive terminal and the negative terminal; a switch electrically coupled to the shorting line that can be selectively opened and closed to provide or remove a dead short across the fuel cell stack; a cathode inlet valve for closing off cathode flow channels at the inlet to the fuel cell stack; a cathode outlet valve for closing off the cathode flow channels at the outlet of the fuel cell stack; a hydrogen source for providing hydrogen to the anode side of the fuel cell stack; and a controller configured to control the cathode inlet valve, the cathode outlet valve, the switch and the hydrogen source, said controller simultaneously or nearly simultaneously closing the switch, closing the cathode inlet valve, closing the cathode outlet valve and opening the hydrogen source so that hydrogen is provided to the anode side of the fuel cell stack and existing air in the cathode side of the fuel cell stack reacts with the hydrogen being introduced to the anode side of the fuel cell stack without creating a voltage potential as a result of the short.