Patent ID: 7144645
Filing Date: 2006-12-05
Classification: H01M,Y02E

Abstract:
1. A method for operating a polymer electrolyte fuel cell comprising, a pair of electrodes sandwiching a polymer electrolyte membrane, a conductive separator, a means for supplying and discharging a fuel gas and an oxidizing gas to and from said electrodes, a moisturizing means for said fuel gas and/or said oxidizing gas, and a means for circulating cooling water in a plane direction parallel to said electrodes, said method comprising the steps of: measuring at least one physical quantity selected from the group consisting of a gas flow rate of said fuel gas, a gas flow rate of said oxidizing gas, a saturated steam pressure in said fuel gas, a steam pressure in said fuel gas, a saturated steam pressure in said oxidizing gas, a steam pressure in said oxidizing gas, a temperature of said electrode and an output current value; regulating at least one physical quantity selected from the group consisting of a flow direction of said cooling water, a temperature of said cooling water, a flow amount of said cooling water, a supply amount of said ftiel gas, a supply amount of said oxidizing gas, a moisture amount in said fuel gas, a moisture amount in said oxidizing gas, a temperature of said electrode, a temperature distribution of said electrode and an output current value; and thereby maintaining a property value Y calculated by the formula (1): wherein V indicates a flow rate (m/sec) of said fuel gas or said oxidizing gas, ΔP is the difference (kgf/m 2 ) between a saturated steam pressure and a steam pressure in said fuel gas or said oxidizing gas and 1≦m≦2 and 1≦n≦2; and wherein at least one selected from the group consisting of m and n is regulated depending on an operating duration of time or output characteristics of said polymer electrolyte fuel cell, such that: when m=1 and n=1, at a current density of 0.3A Y=V×ΔP is in a range of 2000 to 30,000 and at a current density of 0.7A Y=V×ΔP is in a range of 2000 to 70,000; when m=2 and n=1, at a current density of 0.3A Y=V and at a current density of 0.7A Y=V when m=1 and n=2, at a current density of 0.3A Y=V×(ΔP and at a current density of 0.7A Y=V×(ΔP