Patent ID: 7108928

Claim:
A method of thawing frozen water in a fuel cell, applied to the start-up of a fuel cell power plant comprising a fuel cell stack comprising plural laminated fuel cells each of which has an anode and cathode on either side of an electrolyte membrane, and a secondary battery having a positive electrode and a negative electrode to supply a direct current voltage, the method comprising: detecting a temperature of a fuel cell; thawing the frozen water when the temperature is less than a freezing point, by a heat generated by applying the direct current voltage between the anode and cathode to cause the frozen water to undergo electrolysis; and repeating an oxygen/hydrogen generation process wherein the anode is connected to the positive electrode and the cathode is connected to the negative electrode so as to cause the frozen water to undergo electrolysis to generate oxygen at the anode and generate hydrogen at the cathode, and a hydrogen/oxygen generating process wherein the anode is connected to the negative electrode and the cathode is connected to the positive electrode so as to cause the frozen water to undergo electrolysis to generate hydrogen at the anode and generate oxygen at the cathode.