Fuel cell system comprising battery and method of consuming residual fuel in the fuel cell system

A method of consuming residual fuel in a fuel cell system, the method comprising:

• comparing a first power and a second power, the first power being an output power from a fuel cell of the fuel cell system, and the second power being an intrinsic power consumed by the fuel cell system during operation;
• driving the fuel cell system in a power loss mode if the first power is less than the second power, the power loss mode being an operation in which the first power is consumed by at least a converter unit and a charger of the fuel cell system;
• determining whether a back-up battery of the fuel cell system is completely charged if the first power is greater than the second power;
• driving the fuel cell system in a valve OFF driving mode if the back-up battery is determined to be completely charged and the first power is determined greater than the second power, the valve OFF driving mode being an operation in which the converter unit consumes power and an OFF signal is applied to a valve driver of the fuel cell system to consume power from the back-up battery, the valve driver controlling a valve which provides the fuel to the fuel cell;
• driving the fuel cell system in a charge mode when the back-up battery is determined to be not completely charged and the first power is greater than the second power, the charge mode being an operation in which the back-up battery is charged to a full charge state;
• comparing an output voltage from the fuel cell and a set voltage during one of the power loss mode, the charge mode, and the valve OFF driving mode;
• and
• repeating the comparing of the first power with the second power, the driving the fuel cell system in the power loss mode, the determining whether the back-up battery is completely charged, driving the fuel cell system in the valve OFF driving mode, the driving the fuel cell system in the charge mode, and the comparing the output voltage from the fuel cell and the set voltage if the output voltage from the fuel cell is greater than the set voltage.

A method of consuming residual fuel in a fuel cell of a fuel cell system, the method comprising:

• after removing a load from the fuel cell system, determining whether a first power is less than a second power, the first power being a power output of the fuel cell, and the second power being a power required to operate the fuel cell system;
• if the first power is less than the second power, operating the fuel cell system in a power loss mode to consume the residual fuel in the fuel cell;
• if the first power is not less than the second power, determining if a back-up battery is completely charged;
• if the back-up battery is completely charged and the first power is not less than the second power, operating the fuel cell system in a valve OFF driving mode to consume the residual fuel in the fuel cell by discharging the back-up battery through operation of a fuel cell element;
• and
• if the back-up battery is not completely charged and the first power is not less than the second power, operating the fuel cell system in a charge mode to charge the back-up battery and consume the residual fuel in the fuel cell by charging the back-up battery.

A fuel cell system, comprising:

• a fuel cell to supply energy to a load from a fuel;
• a back-up battery to supply energy to the load;
• and
• a controller to control the fuel cell system to consume residual fuel in the fuel cell by alternately charging the back-up battery and consuming power of the back-up battery through the operation of the fuel cell system.

A fuel cell system, comprising:

• a fuel cell to supply energy to a load from a fuel;
• a back-up battery to supply energy to the load;
• a charger disposed between the converter unit and the load to charge the back-up battery;
• a valve driver to control a valve through which fuel enters the fuel cell;
• a first switch disposed between the load and the charger;
• a second switch disposed between the charger and the back-up battery;
• and
• a controller to apply control signals to the charger and the valve driver to consume residual fuel in the fuel cell, after the load is removed from the fuel cell, so that a power of the back-up battery is consumed through the application of a valve OFF signal to the valve driver and the residual fuel is consumed in re-charging the back-up battery.