Patent ID: 7858251
Filing Date: 2010-12-28
Classification: B60L,H01M,Y02E,Y02T

Abstract:
1. A fuel cell system comprising: a fuel cell operated to generate power by reaction of a fuel gas supplied to a fuel gas flow field and an oxygen-containing gas supplied to an oxygen-containing gas flow field; scavenging means for scavenging in at least one of said fuel gas flow field where the fuel gas flows and said oxygen-containing gas flow field where the oxygen-containing gas flows, using a scavenging gas when power generation by said fuel cell is stopped; and water amount detection means for detecting an amount of water produced in said fuel gas flow field as a result of power generation of said fuel cell when operation of said fuel cell is stopped, wherein when the amount of water in said fuel gas flow field is at or below a predetermined value, said scavenging means performs: a first scavenging process for scavenging in said oxygen-containing gas flow field using the scavenging gas at a large flow rate in order to remove liquid droplets in said oxygen-containing gas flow field; a second scavenging process for scavenging in said fuel gas flow field using the scavenging gas at a large flow rate in order to remove liquid droplets in said fuel gas flow field, the second scavenging process performed sequentially either before or after the first scavenging process; and a third scavenging process for scavenging in said oxygen-containing gas flow field after the first scavenging process using a scavenging gas at a small flow rate, which is smaller than the large flow rate.