A power net system of a fuel cell and a method for controlling the same are provided. The power net system includes: a fuel cell to generate electric power through a reaction of a fuel gas and an oxidation gas; batteries to be charged by the electric power generated by the fuel cell or discharged to supply electric power; main lines electrically connecting the fuel cell and the batteries; main relays provided in the main lines to open or allow electrical connections between the fuel cell and the batteries; COD lines branched from the main lines between the fuel cell and the main relays and provided with a COD device to consume input electric power; COD relays provided in the COD lines to open or allow electrical connections to the COD device through the COD lines; and a controller to control the main relays or the COD relays to supply electric power charged in the batteries to the fuel cell.

A fuel cell vehicle includes a fuel cell stack, an air compressor configured to supply air to the fuel cell stack, and a controller configured to increase air compressor driving at a launch control function activation request, charge a battery through an output of the fuel cell stack, thereby preparing to activate a launch control function, and output a signal indicating that the launch control function can be activated when the output of the fuel cell stack or the amount of charging of the battery has reached a preset value.

Various embodiments manage a fuel cell IT grid system to maintain fuel cell temperatures above a threshold temperature. The system may include power modules each including a fuel cell, DC/DC converters each connected to a power module, a DC power bus connected to the DC/DC, IT loads each connected to the DC power bus, a load balancing load connected to the DC power bus, and a control device connected to a first power module. The control device may determine whether a temperature of the first power module exceeds the temperature threshold, determine whether an electrical power output of the power modules exceeds an electrical power demand of the IT loads in response to the temperature exceeding the temperature threshold, and direct excess electrical power output to the load balancing load in response to the electrical power output exceeding the electrical power demand.

An operation control method of a fuel cell system is provided that increases the output of a fuel cell stack by detecting and overcoming the cause of a performance limit when the stack reaches the performance limit during high-altitude operation of a fuel cell vehicle, thereby achieving higher stack performance and vehicle power performance. The method includes determining whether an operation state of the stack corresponds to a predetermined condition in which a stack output limit occurs by determining current operation state information of the stack. Additionally, operating pressure of an air pole is adjusted by changing an opening degree of an air pressure adjusting valve to a control command value based on the operation state of the stack when the operation state corresponds to the predetermined condition in which the stack output limit occurs.

In a fuel cell system, a controller is configured to, to stop the fuel cell system, (a) execute an oxidizing gas consumption process by supplying a fuel gas to an anode and sweeping current from a fuel cell while a supply-side on-off valve and an exhaust-side on-off valve are closed to seal the remaining oxidizing gas in the cathode, and (b) stop sweeping the current at a time point at which the difference between pressure of the cathode that decreases in response to the sweeping of the current and an estimated pressure value of the cathode that decreases by consumption of the oxidizing gas remaining in the cathode in response to the sweeping of the current becomes larger than a predetermined determination threshold value to end the oxidizing gas consumption process.

Provided is a cogeneration system that includes a plurality of fuel cell devices capable of supplying heat and power to a heat load and a power load and a control device connected to the fuel cell devices. The control device determines an operation mode on the basis of at least one of a heat demand value and a power demand value. The control device controls a power generation efficiency and a heat recovery efficiency by controlling the fuel cell devices on the basis of the operation mode determined.

Example implementations relate to data center fuel cells. In some examples, a controller for data center fuel cells can include instructions to: determine when a load for a data center that exceeds a power threshold, determine a first quantity of power to be provided by a first power source and a second quantity of power to be provided by a second power source such that a sum of the first quantity of power and the second quantity of power is equal to or exceeds the power threshold for the data center, provide the first quantity of power utilizing the first power source, wherein the first quantity of power is less than the power threshold, and provide the second quantity of power utilizing the second power source.

On a start of a fuel cell system, (i) when the temperature of a high-voltage secondary battery obtained from a temperature sensor is higher than a predetermined reference value, a controller of the fuel cell system is configured to set an output voltage on a step-down side of a DC-DC converter to a higher voltage than a voltage of a low-voltage secondary battery and subsequently start an FC auxiliary machine using electric power from the high-voltage secondary battery. (ii) When the temperature of the high-voltage secondary battery obtained from the temperature sensor is equal to or lower than the predetermined reference value, on the other hand, the controller of the fuel cell system is configured to set the output voltage on the step-down side of the DC-DC converter to a lower voltage than the voltage of the low-voltage secondary battery and subsequently start the FC auxiliary machine using the electric power from the high-voltage secondary battery.

A technique of diagnosing a fuel cell stack is provided. In particular, current and voltage of a fuel cell stack are measured during driving of a fuel cell vehicle and the current and voltage are sequentially stored. It is then determined based on the stored current whether the vehicle is being operated at constant current. Different factors are analyzed depending on whether the vehicle is being operated at constant current, and then it is determined whether the fuel cell stack is in a normal state. A moisture supply into the fuel cell stack is calculated if it is determined that the fuel cell stack is not in the normal state. Based on the calculated moisture supply, whether the fuel cell stack is in a dryout state is diagnosed.

The present disclosure provides a fuel cell system comprising a hot box, an air tube, an electrical heater and a thermal sensor. The hot box may comprise a fuel cell stack having a plurality of fuel cell units joined together. Each fuel cell unit of the fuel cell stack unit has an anode, a cathode and an electrolyte sandwiched between the anode and cathode. An air tube having an upper end and lower end is configured to receive ambient air at a second inlet. The electrical heater is integrated within the air tube and configured to heat the fuel cell stack by introducing hot air at a cathode side of a plurality of fuel cell units. Further, the fuel system is configured to operate in different modes comprising a startup mode, a normal mode, a dump load mode and hot standby mode with the use of the integrated electrical heater.