A fuel cell system configured to supply electric power to load includes: a fuel cell; and a control unit configured to set target electric power to be generated by the fuel cell and control electric power generation by the fuel cell such that the fuel cell generates the target electric power. The control unit is configured to, when setting the target electric power using request electric power that the load requests the fuel cell to generate, execute a fluctuation suppression process for making a fluctuation of the target electric power smaller than a fluctuation of the request electric power.

A hierarchical fault classification method for a fuel cell system, a multi-stage fault diagnosis method therefor, and a fault diagnosis device therefor are disclosed. The fuel cell system is divided into a subsystem, a component, and an element step by step. The multi-stage fault diagnosis method includes detecting a subsystem, a fault of which occurs, in the fuel cell system composed of a plurality of subsystems and detecting an upper-level component, which causes the fault, among upper-level components included in the subsystem, the fault of which occurs, using measurement data and a control signal.

A hierarchical fault classification method for a fuel cell system, a multi-stage fault diagnosis method therefor, and a fault diagnosis device therefor are disclosed. The fuel cell system is divided into a subsystem, a component, and an element step by step. The multi-stage fault diagnosis method includes detecting a subsystem, a fault of which occurs, in the fuel cell system composed of a plurality of subsystems and detecting an upper-level component, which causes the fault, among upper-level components included in the subsystem, the fault of which occurs, using measurement data and a control signal.

A fuel cell system includes a fuel cell stack including fuel and air electrodes, a fuel gas supply module configured to supply hydrogen and oxygen, as fuel gases, to the fuel cell stack, a fuel gas supply line including channels through which the fuel gases are supplied to the fuel cell stack, a humidification module disposed in the fuel gas supply line and configured to supply moisture to the fuel gases, and a controller configured to control the fuel gas supply line such that the fuel gases bypass the humidification module and are directly supplied to the fuel cell stack when temperature of the fuel cell stack is determined low at an initial stage of operation of the fuel cell stack, and the fuel gases pass through the humidification module and are supplied to the fuel cell stack when the temperature reaches a normal temperature.

A fuel cell system includes a fuel cell stack including fuel and air electrodes, a fuel gas supply module configured to supply hydrogen and oxygen, as fuel gases, to the fuel cell stack, a fuel gas supply line including channels through which the fuel gases are supplied to the fuel cell stack, a humidification module disposed in the fuel gas supply line and configured to supply moisture to the fuel gases, and a controller configured to control the fuel gas supply line such that the fuel gases bypass the humidification module and are directly supplied to the fuel cell stack when temperature of the fuel cell stack is determined low at an initial stage of operation of the fuel cell stack, and the fuel gases pass through the humidification module and are supplied to the fuel cell stack when the temperature reaches a normal temperature.

Methods and systems are provided for a cooling system for a vehicle having a fuel cell system. The cooling system comprises a first cooling circuit configured to cool a first set of vehicle components and a second cooling circuit configured to cool a second set of vehicle components. The fuel cell system is distributed between the first set of vehicle components and the second set of vehicle components.

A system for providing oxygen to a fuel cell circuit includes a compressor and a fuel cell stack having a plurality of fuel cells. The system also includes a plurality of pipes and a pressure sensor designed to detect pressure at a first location. The system also includes a memory to store a model of the fuel cell circuit and an ECU. The ECU determines a control signal corresponding to desirable operation of the compressor and determines flow values of the gas through each component based on the detected pressure and the model of the fuel cell circuit. The ECU also determines pressure values of each component based on the determined flow values and the model of the fuel cell circuit. The ECU also controls operation of the compressor based on the control signal, at least one of the flow values, and at least one of the pressure values.

A system for providing oxygen to a fuel cell circuit includes a compressor and a fuel cell stack having a plurality of fuel cells. The system also includes a plurality of pipes and a pressure sensor designed to detect pressure at a first location. The system also includes a memory to store a model of the fuel cell circuit and an ECU. The ECU determines a control signal corresponding to desirable operation of the compressor and determines flow values of the gas through each component based on the detected pressure and the model of the fuel cell circuit. The ECU also determines pressure values of each component based on the determined flow values and the model of the fuel cell circuit. The ECU also controls operation of the compressor based on the control signal, at least one of the flow values, and at least one of the pressure values.

A fuel gas supply system for a fuel cell includes an injector, an inlet pressure acquisition unit, a discharge valve, a hydrogen partial pressure acquisition unit, and a controller. The controller is configured to stop driving the injector when a hydrogen partial pressure reaches or exceeds a first upper limit value in a state where the injector is being driven, and start driving the injector when the hydrogen partial pressure falls to or below a first lower limit value in a state where the injector is stopped. The controller is configured to open the discharge valve when an inlet pressure reaches or exceeds a second upper limit value in a state where the discharge valve is closed, and close the discharge valve when the inlet pressure falls to or below a second lower limit value in a state where the discharge valve is open.

The fuel cell system is a fuel cell system comprising a fuel cell stack assembly, wherein the fuel cell stack assembly comprises a fuel cell stack and a data storage configured to store a start-up history of the fuel cell stack; wherein the data storage comprises a detector configured to detect a presence or absence of a connection to at least one selected from the group consisting of an external power source and an external communication device; and wherein the data storage starts up when a voltage of the fuel cell stack is a predetermined threshold value or more.