| 摘要 |
In a fuel cell system and its controlling method, the fuel cell system includes a stack (21) including fuel cells each having a polymer electrolyte membrane, and a controller (61). The controller (61) is responsive to detected outputs of a displacement sensor (27) and a temperature sensor (27) and controls such that, when the polymer electrolyte membrane is discriminated to remain in an excessively dry state, a shut-off valve (37) is applied with a "close" control signal to interrupt the supply of fuel gas to the stack (21) and, concurrently, a shut-off valve (41) is applied with an "open" control signal to allow air to be supplied to the stack (21) while applying a pump control signal to a pump (57) so as to maximize its rotational speed for thereby increasing the flow rate of pure water (59) to be circulated to the humidifier (35) from a pure water tank (55). Simultaneously, a timer of the controller (61) is operated to begin counting an incremental time. As a result, air is excessively humidified by the humidifier (35) and is supplied to the stack (21) via the shut-off valve (41). |
