Patent ID: 8129044
Filing Date: 2012-03-06
Classification: H01M,Y02E

Abstract:
1. A method for operating a fuel cell system comprising: a fuel cell comprising a fuel gas channel on an anode side and an oxidant gas channel on a cathode side, which is configured to generate electricity using a fuel gas and an oxidant gas; a diluting unit configured to dilute gas discharged from the fuel gas channel by mixing the discharged gas with a dilution gas, and to exhaust the diluted gas to outside; and a purge valve configured to purge gas in the fuel gas channel to the diluting unit; in which method cathode scavenging is performed first and anode scavenging is performed subsequently, comprising: a step of determining, during the cathode scavenging, whether or not a concentration of hydrogen exhausted from the diluting unit is less than a first specific concentration which is an upper limit value, and when it is determined that the hydrogen concentration is less than the first specific concentration, maintaining the purge valve in an opened state to perform purging; and a step of determining whether or not a concentration of hydrogen exhausted from the diluting unit is a second specific concentration or more which requires a dilution assist, and when it is determined that the hydrogen concentration is the second specific concentration or more, supplying a dilution assist gas to the diluting unit to assist dilution.