Abstract: A direct methanol type fuel cell system provided with a tank for storing an antifreeze that is injected into at least said unit cell or a cell stack and held in place at the time of stand-by operation of the direct methanol type fuel cell system. At the time of starting operation an oxidant gas is supplied to the cathode side and the antifreeze is removed from the unit cell or the cell stack. After starting operation, the passage between the antifreeze tank and the unit cell or the cell stack is closed and an aqueous solution of methanol is supplied as liquid fuel from a fuel tank to the anode side.

Abstract: Elution of a fuel electrode material into a fuel in a direct methanol fuel cell is monitored. The elution arises resulting from elution of a perfluorosulfonic acid polymer in the fuel electrode into the fuel in a high-concentration fuel equal to or more than 2 M or at an operating temperature equal to or more than 80° C. The electrode catalyst elutes into the fuel and the characteristic degrades. Operating conditions of the fuel cell, i.e., the fuel concentration and the operating temperature are limited to be less than 2 M and 80° C. or less, respectively. In addition, the elution characteristic is evaluated at the time of manufacture of the fuel cell and quality control is conducted. Further, existence of the elution is detected by a color of the fuel etc., and when the elution is detected, the upper limits of the operating temperature and the fuel concentration are decreased, so that further elution is prevented.

Abstract: Elution of a fuel electrode material into a fuel in a direct methanol fuel cell is monitored. The elution arises resulting from elution of a perfluorosulfonic acid polymer in the fuel electrode into the fuel in a high-concentration fuel equal to or more than 2 M or at an operating temperature equal to or more than 80° C. The electrode catalyst elutes into the fuel and the characteristic degrades. Operating conditions of the fuel cell, i.e., the fuel concentration and the operating temperature are limited to be less than 2 M and 80° C. or less, respectively. In addition, the elution characteristic is evaluated at the time of manufacture of the fuel cell and quality control is conducted. Further, existence of the elution is detected by a color of the fuel etc., and when the elution is detected, the upper limits of the operating temperature and the fuel concentration are decreased, so that further elution is prevented.

Abstract: A direct methanol type fuel cell system provided with a tank for storing an antifreeze that is injected into at least said unit cell or a cell stack and held in place at the time of stand-by operation of the direct methanol type fuel cell system. At the time of starting operation an oxidant gas is supplied to the cathode side and the antifreeze is removed from the unit cell or the cell stack. After starting operation, the passage between the antifreeze tank and the unit cell or the cell stack is closed and an aqueous solution of methanol is supplied as liquid fuel from a fuel tank to the anode side.