Patent ID: 8790834

Claim:
A fuel cell system comprising: a fuel cell; a gas-supply passage via which anode gas is supplied to the fuel cell; a gas-discharge passage via which anode gas is discharged from the fuel cell, the gas-discharge passage having an end which is substantially closed and configured to expel the anode gas discharged from the fuel cell at a very low rate that prevents deterioration of a power generation performance of the fuel cell system; a communication passage via which the gas-discharge passage communicates with the gas-supply passage; an interrupting device having a single pump or a single set of an ejector and a valve provided in the communication passage and operable to interrupt the flow of anode gas to control a degree of hydration of the fuel cell; and a controller programmed to: normally maintain the communication passage in a closed state using the single pump or the single set of the ejector and the valve, determine whether a predetermined condition related to the operation state of the fuel cell is satisfied, control the single pump or the single set of the ejector and the valve so as to place the communication passage in an opened state if the predetermined condition is satisfied, determine whether the load on the fuel cell is below a first reference load, when the load on the fuel cell is below the first reference load, determine that the predetermined condition is satisfied and operate the single pump or the single set of the ejector and the valve to open the communication passage, and control the single pump or the single set of the ejector and the valve to close the communication passage if it is determined that the load of the fuel cell is equal to or greater than the first reference load.