Patent ID: 9337502
Filing Date: 2016-05-10
CPC Classification: H01M,Y02E,Y02T

Claim Text:
1. A fuel cell system comprising: a fuel cell stack which is supplied with a fuel gas and an oxidation gas to generate electric power by an electrochemical reaction; an oxidation gas piping system which supplies the oxidation gas to the fuel cell stack; and a fuel gas piping system which supplies the fuel gas to the fuel cell stack, the fuel gas piping system including a supply path through which the fuel gas to be supplied to the fuel cell stack from a fuel gas supply source flows; a circulation path which returns a fuel off-gas discharged from the fuel cell stack to the supply path; and a circulating pump which feeds under pressure the fuel off-gas in the circulation path to the supply path, the fuel cell system being capable of, at starting below a freezing point, selectively performing a rapid warm-up operation to generate the electric power at a stoichiometric ratio between the oxidation gas and the fuel gas lower than that at starting at ordinary temperature, while revolving the circulating pump, the fuel cell system further comprising; a clogging determination unit which determines, at the starting below freezing point, whether or not clogging arises from freezing in a fuel gas passage of the fuel cell stack, or the fuel gas piping system, while revolving the circulating pump; and a rapid warm-up controller which, when it is determined by the clogging determination unit during the rapid warm-up operation that the clogging arises, is programmed to stop the circulating pump, and to change restarting conditions of the circulating pump in accordance with at least three degrees of the clogging.