FUEL CELL SYSTEM AND START-UP METHOD THEREFOR

摘要

The present invention relates to a fuel cell system comprising a fuel cell that generates power with fuel gas and oxidant gas; a hydrogen supply flow channel (2a) that is connected between a hydrogen tank (2) and the fuel cell and through which hydrogen supplied to the fuel cell flows; a hydrogen supply control valve (5) installed on the hydrogen supply flow channel (2a) that is for adjusting an amount of hydrogen supplied from the hydrogen tank (2); an air emission flow channel (3b); a fuel exhaust line (2b) that is connected to the fuel cell (1) and which merges upstream of an air regulator (9) provided on air emission flow channel (3b) with air emission flow channel (3b) at the downstream side of a purge valve (8) installed on the fuel exhaust line (2b) so as to exhaust the fuel gas to the outside of the fuel cell (1); and through which fuel gas exhausted from the fuel cell (1) flows; a bypass line (6) that connects the hydrogen supply flow channel (2a) with the fuel exhaust line (2b); a circulating pump (7) provided with a revolution speed sensor, installed on the bypass line (6) so as to circulate the fuel gas exhausted from the fuel cell (1) so that it travels from the fuel exhaust line (2b) to the hydrogen supply flow channel (2a); an oxygen concentration sensor (31) at the anode inlet and a controller (20) configured to perform a start-up control when oxidant is detected in an anode of the fuel cell when the fuel cell starts up from an unloaded state in which the fuel cell is not generating an electrical output, wherein the controller (20) is configured to first close the purge valve (8) and to then start the operation of the circulating pump (7) and to then control the circulating pump (7) to the maximum revolution speed that can be controlled in a stable manner, said maximum revolution speed being determined based on the values of the revolution speed sensor, and to then narrow the opening of the air regulator (9) and to then open hydrogen supply control valve (5) and to further control the circulating pump (7) while the purge valve (8) is closed to recirculate the fuel gas exhausted from the fuel cell (1) back to the hydrogen supply flow channel (2a) such that the oxygen concentration determined by the oxygen concentration sensor (31) reaches a predetermined value or less and to then lower the revolution speed of the circulating pump (7) to a revolution speed that corresponds to the idle state and to then start power generation and open the purge valve (8).