Abstract: Coolant passages (11a, 11b) are provided in unit cells (17a, 17b) which form a laminate (170) of the unit cells (17a, 17b). A coolant supply manifold (12) which distributes coolant from a coolant recirculation device (100) to the coolant passages (11a, 11b), and a coolant discharge manifold (13) which recovers coolant from the coolant passage (11a, 11b) to the coolant recirculation device (100), pass through the laminate (170). The coolant supply manifold (12) and coolant discharge manifold (13) are connected by two bypass passages (14a, 14b). At low temperature, heat transfer from the high temperature parts to the low temperature parts is promoted by shutting off circulation of coolant between the coolant recirculation device (100) and the laminate (170) by a valve (3, 4), and recirculating coolant inside the fuel cell stack (1) via the bypass passages (14a, 14b).

Abstract: Coolant passages (11a, 11b) are provided in unit cells (17a, 17b) which form a laminate (170) of the unit cells (17a, 17b). A coolant supply manifold (12) which distributes coolant from a coolant recirculation device (100) to the coolant passages (11a, 11b), and a coolant discharge manifold (13) which recovers coolant from the coolant passage (11a, 11b) to the coolant recirculation device (100), pass through the laminate (170). The coolant supply manifold (12) and coolant discharge manifold (13) are connected by two bypass passages (14a, 14b). At low temperature, heat transfer from the high temperature parts to the low temperature parts is promoted by shutting off circulation of coolant between the coolant recirculation device (100) and the laminate (170) by a valve (3, 4), and recirculating coolant inside the fuel cell stack (1) via the bypass passages (14a, 14b).

Abstract: A fuel cell system includes a fuel cell (1) having a water passage and passage for gas required for power generation, a first protection device (5, 10) which prevents freezing of water in the fuel cell by maintaining the temperature of the fuel cell (1), and a second protection device (11, 12) which prevents freezing of water in the fuel cell by discharging the water in the fuel cell (1). A controller (50) selects one of the first protection device (5, 10) and the second protection device (11, 12) as the protection device to be used when the fuel cell (1) has stopped, and the fuel cell (1) is protected from freezing of water by operating the selected protection device.

Abstract: A fuel cell system includes a fuel cell (1) having a water passage and passage for gas required for power generation, a first protection device (5, 10) which prevents freezing of water in the fuel cell by maintaining the temperature of the fuel cell (1), and a second protection device (11, 12) which prevents freezing of water in the fuel cell by discharging the water in the fuel cell (1). A controller (50) selects one of the first protection device (5, 10) and the second protection device (11, 12) as the protection device to be used when the fuel cell (1) has stopped, and the fuel cell (1) is protected from freezing of water by operating the selected protection device.