Fuel cell stack, fuel cell system, and method for controlling fuel cell stack

Abstract

The present disclosure provides a fuel cell stack, a fuel cell system and a method for controlling a fuel cell stack, which can reduce obstruction of reactive gas fluid channels caused by freezing of retained water, while allowing size to be reduced. The fuel cell stack of the disclosure comprises water storage units that are formed between every two adjacent fuel cell unit cells, surrounded by the adjacent separators, the wall members and the gaskets, and that communicate with the reactive gas discharge manifold via the gaps of the wall members. The fuel cell system of the disclosure controls either or both the valve and compressor in a reactive gas supply channel and/or the valve in a reactive gas discharge channel, to cause liquid water retained in the water storage units to be discharged out of the fuel cell stack. The controlling method of the disclosure includes reducing the pressure in and scavenging the interior of the reactive gas discharge manifold, to cause the liquid water that has been discharged into the reactive gas discharge manifold to be discharged out of the fuel cell stack.