Fuel cell system

摘要

A fuel cell system includes a fuel cell stack, a cathode supply flow passage which is connected to the fuel cell stack and through which cathode gas flows, a cathode off-gas flow passage which is connected to the fuel cell stack and discharges cathode off-gas, a bypass flow passage which is branched off from the cathode supply flow passage and through which a part of the cathode gas flows while bypassing the fuel cell stack, a bypass valve configured to regulate a bypass flow rate in the bypass flow passage and include an atmosphere communication hole, and an anode off-gas flow passage which is connected to the fuel cell stack and discharges anode off-gas. The anode off-gas flow passage joins the bypass flow passage at a side downstream of the cathode off-gas flow passage or the bypass valve, and the bypass valve is formed with a clearance configured to leak a predetermined quantity of gas even in a fully closed state.

主权项

1. A fuel cell system, comprising:
a fuel cell stack; a cathode supply flow passage which is connected to the fuel cell stack and through which cathode gas flows; a cathode off-gas flow passage which is connected to the fuel cell stack and discharges cathode off-gas; a bypass flow passage which is branched off from the cathode supply flow passage, joins the cathode off-gas flow passage, and through which a part of the cathode gas flows while bypassing the fuel cell stack; a bypass valve configured to regulate a bypass flow rate in the bypass flow passage; and an anode off-gas flow passage which is connected to the fuel cell stack and discharges anode off-gas; wherein: the anode off-gas flow passage joins the bypass flow passage at a side downstream of the cathode off-gas flow passage or the bypass valve; a housing of the bypass valve is formed with an atmosphere communication hole allowing communication between the interior of the housing and atmosphere and having a possibility of causing the anode off-gas flowing back in the bypass flow passage to flow out to the atmosphere; and a clearance is formed in a chamber in the bypass valve through which the cathode gas flows from the cathode supply flow passage, the clearance being configured to leak a predetermined quantity of gas toward the cathode off-gas flow passage even in a fully closed state.