Patent ID: 8216731

Claim:
A control method for a fuel cell, which comprises a membrane, and a positive electrode and a negative electrode which sandwich the membrane therebetween, wherein the fuel cell produces electric power from a reaction of reactive gases via the membrane when the reactive gases are supplied to the positive and negative electrodes, the method comprising the following steps of: monitoring a temperature of the fuel cell when the fuel cell is in a state in which electricity is not being generated; estimating areas of the positive and negative electrodes available for producing power, each area of each positive electrode and each area of each negative electrode for which an estimation is performed defining a power production effective area; calculating a current density of the estimated power production effective areas based on a current required by a load connected to the fuel cell; determining an amount of reactive gases to be supplied to the fuel cell based on the calculated current density; and supplying the determined amount of reactive gases to the fuel cell, wherein the power production effective areas of the positive and negative electrodes are estimated using a power production effective area estimation map in which the temperature of the monitored fuel cell and the power production effective areas are associated with each other, the power production effective areas being estimated based on the temperature of the monitored fuel cell associated therewith in the power production effective area estimation map, and the power production effective area estimation map has a hysteresis characteristic in which a relationship between the power production effective areas and the temperature of the monitored fuel cell during a rise in the temperature of the monitored fuel cell differs from a relationship between the power production effective areas and the temperature of the monitored fuel cell during a decline in the temperature of the monitored fuel cell when a lowest temperature of the monitored fuel cell is lower than a freezing temperature of an antifreeze within the monitored fuel cell.