A fuel cell system having a direct liquid fuel cell that uses a liquid containing a formic acid or an alcohol as a fuel includes: a fuel tank that stores the fuel to be supplied to the fuel cell; a fuel supply device that supplies the fuel in the fuel tank to the fuel cell; and a bubbling device that blows an inert gas into the fuel stored in the fuel tank.

A method of correcting error of hydrogen pressure sensor of vehicle fuel cell system, may checking, whether an opening ratio of a hydrogen pressure regulation valve is in a normal range by use of data map; checking whether a hydrogen purge valve is opened when the opening ratio of the hydrogen pressure valve is not within the normal range; changing the opening ratio of the hydrogen pressure regulation valve at least one time when the hydrogen purge valve is determined as being opened, and detecting two or more measurement values of the hydrogen pressure sensor at two or more different opening ratios of the hydrogen pressure regulation valve; and comparing, the two or more measurement values of the hydrogen pressure sensor detected at the two more opening ratios, respectively with predetermined pressure values corresponding to the opening ratios, and correcting errors between the measurement values and the predetermined pressure values.

A method of detecting degradation of a membrane electrode assembly of a fuel cell is provided. In the method, it is possible to detect degradation (cross leakage) of the fuel cell. In the measurement step, the pressure drop value of the pressure of the fuel gas which decreases in the power generation state after discharging of the predetermined amount of the fuel gas, in each predetermined period of time is measured a plurality of times. Thereafter, in the determination step, it is determined that the membrane electrode assembly has been degraded in the case where the minimum pressure drop value, among a plurality of pressure measurement values, exceeds a threshold value.

A fuel cell mount apparatus includes a plurality of fuel cell stacks, a pipe arrangement, a fluid adjustment part, a pressure detection part, and a control device. The pipe arrangement is individually connected to each of the fuel cell stacks. The fluid adjustment part adjusts a pressure or a flow rate of a fluid which flows through the pipe arrangement. The pressure detection part is disposed on a portion which requires a desired pressure or flow rate of the fluid in the pipe arrangement and detects the pressure of the fluid. The control device controls the fluid adjustment part on the basis of a detection result of the pressure detection part.

System for recirculating hydrogen in a fuel cell including a tank having an inlet connectable to an outlet of the fuel cell and an outlet connectable to a line for feeding hydrogen to the fuel cell; the recirculation system includes a first check valve and a second check valve; the first check valve can be inserted between the outlet of the fuel cell and the inlet of the tank, for adjusting a flow from the fuel cell to the tank whilst the second check valve can be inserted between the outlet of the tank and the hydrogen feed line, for adjusting a flow of hydrogen from the tank to the feed line.

a fuel cell system without a high pressure line of a hydrogen supplying system, including a gas charging line formed between a gas charging station and a high pressure vessel charged with gas by the gas charging station, and a gas supplying line formed between the high pressure vessel and a stack, includes: a regulator provided in the gas supplying line; a solenoid valve provided in the gas supplying line between the regulator and the high pressure vessel; and a check valve provided in a bypass line connecting one point of the gas supplying line between the regulator and the solenoid valve and one point of the gas charging line.

A method for controlling a carbon dioxide utilization in a fuel cell assembly includes: measuring a voltage across the fuel cell assembly; determining an estimated carbon dioxide utilization of the fuel cell assembly based on at least the measured voltage across the fuel cell assembly by determining an expected voltage of the fuel cell assembly based on at least a temperature of the fuel cell assembly, a current density across the fuel cell assembly, a fuel utilization of the fuel cell assembly, and a cathode oxygen utilization of the fuel cell assembly; determining the estimated carbon dioxide utilization based on a comparison between the measured voltage and the determined expected voltage; comparing the determined estimated carbon dioxide utilization to a predetermined threshold utilization; and upon determining that the determined estimated carbon dioxide utilization is higher than the predetermined threshold utilization, reducing the carbon utilization of the fuel cell assembly.

A device for controlling compensation for an air flow rate upon discharge of hydrogen off-gas and a method for controlling compensation for an air flow rate using the same is an air flow rate control device configured to control a flow rate of air supplied to a fuel cell cathode through an air supply unit of a fuel cell system, wherein the air flow rate control device is configured to determine whether a fuel discharge valve of the fuel cell system is opened and determine a fuel diffusion amount per unit time, wherein the fuel diffusion amount corresponds to an amount of the hydrogen off-gas discharged through the fuel discharge valve and diffused into an air supply unit through a humidifier, and compensate a target air flow rate depending on an oxygen concentration reduction proportion, determined according to the determined fuel diffusion amount per unit time and flow rate information of the air supply unit.

A pressure control system of a fuel cell stack includes: an air supply control unit for controlling a revolutions per minute (RPM) of an air compressor for supplying air to a cathode side of the fuel cell stack based on a required output of the fuel cell stack; a hydrogen supply control unit for controlling a pressure at an anode side of the fuel cell stack with a target pressure based on the required output of the fuel cell stack; and a differential pressure control unit for controlling the air supply control unit or the hydrogen supply control unit to calculate a differential pressure between the anode side and the cathode side of the fuel cell stack, and to modify the target pressure or the RPM of the air compressor based on the calculated differential pressure.

Disclosed is a system for determining a hydrogen supply failure of a fuel cell, the system including: a fuel cell, a plurality of hydrogen tanks having hydrogen, a hydrogen supply line connected to the hydrogen tanks and supplying hydrogen from the hydrogen tanks to the fuel cell, a plurality of tank valves mounted on the hydrogen tanks, respectively, and discharging hydrogen in the hydrogen tanks to the hydrogen supply line when opening, a pressure sensor sensing pressure in the hydrogen supply line, and a determiner determining poor opening of the hydrogen tanks on the basis of pressure information sensed by the pressure sensor.