Abstract:
PURPOSE: A method for operating a polymer electrolyte fuel cell below the freezing point of water and its apparatus are provided, to prevent the deterioration of properties of a membrane-electrode assembly by inhibiting the freezing of water of the membrane-electrode assembly, thereby improving the stability of the fuel cell even at a temperature below the freezing point of water. CONSTITUTION: The method comprises the steps of flowing a dry gas for several seconds and charging a solution having a low freezing point into the anode of the fuel cell before the temperature drops below the freezing point water when the polymer electrolyte fuel cell is stopped after operation. Preferably the solution having a low freezing point is methanol, ethylene glycol, ethanol or butanol. The polymer electrolyte fuel cell is operated with flowing only dry gas when it is re-operated at a temperature below the freezing point of water and its is operated with flowing the moist gas normally when the temperature increases over the freezing point of water.
Abstract:
PURPOSE: Provided is a method for producing an electrode being excellent in a hydrogen ion transfer property and activity cell which includes applying a layer of carbon powder on a gas diffusion layer, applying a catalyst ink on the carbon layer to form a catalyst layer; and applying a solution of an ionomer on the catalyst layer. CONSTITUTION: The method comprises steps of (a) applying a layer of carbon powder(22) containing 10 to 50 wt% of polytetrafluoroethylene on a gas diffusion layer(21); (b) applying a catalyst ink on the carbon layer containing a polymer electrolyte ionomer, a catalyst and an organic solvent to form a catalyst layer(23); and (c) applying a solution of polymer electrolyte ionomer dispersed in a hydrophilic solvent on the catalyst layer to form an ionomer layer(24). By this method, an electrode being excellent in hydrogen ion transfer and its activity can be obtained with a small amount of catalyst.
Abstract:
PURPOSE: A polymer electrolyte fuel cell is provided for manufacturing the high reliable unit cell or stack and accomplishing superior gas-sealing effect with no leak of gas by additionally attaching at least one specific gasket to the structure of the fuel cell. CONSTITUTION: The polymer electrolyte fuel cell comprises a plurality of unit cells laminated together and equipped with at least one gasket(2, 4) between a separator plate(1) and the electrolyte-electrolyte membrane assembly(3). The gasket has passages(6-21) for passing gas through at the center part, electrodes at its edge part and a rib having a width of 1-2mm and a thickness of 0.1-0.3mm around the peripheral side of the passage to seal gas stream. The rib(s) is(are) attached to one side or both sides of the gasket.