Fuel cell system control during low efficiency operation

摘要

Provided is a fuel cell system including: a fuel cell which generates power by an electrochemical reaction between an oxidant gas supplied to an oxidant gas flow path and a fuel gas supplied to a fuel gas flow path; and a controller which adjusts an amount of the oxidant gas supplied to the fuel cell and a voltage of the fuel cell. The controller has an obstruction degree determining unit which determines a degree of obstruction of the oxidant gas flow path based on a stoichiometric ratio of the oxidant gas and the voltage of the fuel cell during a low-efficiency operation in which the stoichiometric ratio of the oxidant gas is reduced from the stoichiometric ratio of the oxidant gas during a normal operation and heat discharged from the fuel cell is increased from that during the normal operation. This improves stability of the low-efficiency operation of the fuel cell system.