Toyota Jidosha Kabushiki Kaisha

Aisin Aw Co., Ltd.

Yasuhiro Nonobe

Yoshio Kimura

Tsukuo Ishitoya

Kenji Kurita

Joji Yoshimura

Minobu Mizuno

Kiyoshi Yoshizumi

Kazunori Yanagihara

Keiji Yamane

Munehisa Horiguchi

Yoshikazu Tohata

Shinpei Miura

A fuel cell system has a fuel cell stack and a controller. The fuel cell stack is formed by stacking cells. The controller executes first cell voltage recovery processing when the cell voltage of a first cell group, placed at each end of the fuel cell stack, is below a first lower limit voltage threshold and executes second cell voltage recovery processing, which is different from the first cell voltage recovery processing, when the cell voltage of a second cell group, placed at substantially the center of the fuel cell stack, is below a second lower limit voltage threshold.

Fuel cell system

The fuel cell system includes a storage portion, a fuel cell, a fuel supply portion, a hydrogen circulation system and a boil-off gas supply portion. The storage portion stores liquid hydrogen. The fuel cell uses hydrogen gas as fuel gas. The fuel supply portion provides hydrogen gas to an anode of the fuel cell. The hydrogen gas is generated caused by a vaporization of liquid hydrogen stored in the storage portion. The hydrogen circulation system includes the anode of the fuel cell. The boil-off gas supply portion provides boil-off gas generated in the storage portion to the hydrogen circulation system.

In a fuel cell unit that generates electric power using fuel gas supplied via an anode gas passage and air supplied via a cathode gas passage, an anode-off gas passage is connected to the downstream side of the anode gas passage. An orifice is provided at the anode-off gas passage and anode-off gas is discharged to the downstream side via the orifice.

Fuel cell system and method for controlling fuel cell system

Consumed hydrogen-off gas is discharged from a fuel cell via a hydrogen-off gas exhaust flow passage. Consumed oxygen-off gas is discharged from the fuel cell via an oxygen-off gas exhaust flow passage. The oxygen-off gas flowing through the oxygen-off gas exhaust flow passage and the hydrogen-off gas flowing through the hydrogen-off gas exhaust flow passage are mixed and diluted in a mixing portion. The gases mixed in the mixing portion flow into a combustor via a gas-liquid separator. The combustor, which includes a platinum catalyst, causes hydrogen contained in the mixed gases to react with oxygen by combustion and further reduces the concentration of hydrogen contained in the mixed gases. The mixed gases whose concentration of hydrogen has been reduced by the combustor is discharged to the atmosphere.

Onboard fuel cell system and method of discharging hydrogen-off gas

An on-board fuel cell system adapted to be installed on a motor vehicle includes a main passage connecting a hydrogen-gas storage device with an inlet of a fuel cell, a circulation passage that connects an outlet of the fuel cell with a first point in the main passage, a pump disposed in the circulation passage, and a bypass passage that connects a second point between the outlet of the storage device and the first point, with a third point located in the circulation passage between the outlet of the fuel cell and the pump. During a normal operation condition of the system, the hydrogen gas flows from the storage device to the fuel cell through the main passage, and hydrogen gas discharged from the fuel cell returns to the main passage through the circulation passage. When the pressure of the hydrogen gas is lower than a reference pressure, the pump operates to draw the hydrogen gas out of the storage device and feed the hydrogen gas from the main passage to the circulation passage through the bypass passage, and to the fuel cell through the main passage.

On-board fuel cell system and method of controlling the same

In a polymer electrolyte fuel cell system, a condition of humidification of electrolyte membranes is precisely determined, and adjustment is performed so that the condition of humidification of the electrolyte membranes substantially remains within a proper range. The system determines a condition of humidification of the electrolyte membranes of the fuel cell based on a differential value of the resistance of the fuel cell detected by a resistance detector when the electric current outputted by the fuel cell equals a predetermined value. The current from the cell is detected by an ammeter. The fuel cell is formed by stacking electrically conductive electrodes and separators, and proton-conductive electrolyte membranes. The electric conductivity of the electrodes and the separators is not affected by the humidification condition thereof, whereas the proton-conductivity of the electrolyte membranes greatly changes depending on the condition of humidification thereof. Therefore, the changing rate of the resistance of the fuel cell directly represents the changing rate of the proton-conductivity of the electrolyte membranes, so that the humidification condition of the electrolyte membranes can be precisely determined.

Fuel cell system with humidity determination

An inexpensive and corrosion resistant metal-made gas separator includes a base formed by joining formed stainless steel base sheets face to face. The base carries on each of opposite surfaces thereof a first coating layer formed by plating with tin. The base is also coated with a second coating layer of a thermal expansion graphite. When incorporated into a fuel cell, the separator contacts gas diffusion electrodes that are formed from a carbon material similar to the carbon material of the second coating layer, so that the contact resistance is reduced. The first coating layer is formed after a passive state coating is removed from the stainless steel surface, so that an increase in the internal resistance of the separator caused by the passive state coating is substantially prevented.

Separator for fuel cell, fuel cell incorporating the same, and method of production of the same

A power supply system 10 with a stack of fuel cells 20 and a storage battery 30 includes a remaining charge monitor 46 for measuring the remaining charge of the storage battery 30. The remaining charge monitor 46 detects the remaining charge of the storage battery 30 at the time of stopping operation of the power supply system 10. In case that the remaining charge of the storage battery 30 is not greater than a predetermined level, the fuel cells 20 continuously charge the storage battery 30 until the remaining charge reaches the predetermined level. The power supply system 10 is stopped after the charging operation of the storage battery 30 has been accomplished. At a next start of the power supply system, the storage battery 30 functions as a primary power source to supply electric power to a loading until the warm-up of the fuel cells 20 is completed.

Power supply system, electric vehicle with power supply system mounted

A power supply system 10 with a stack of fuel cells 20 and a storage battery 30 includes a remaining charge monitor 42 for measuring the remaining charge of the storage battery 30. At the time of starting the power supply system 10, the remaining charge monitor 42 detects the remaining charge of the storage battery 30. The power supply system 10 estimates output electric current of the fuel cells 20 based on the observed remaining charge of the storage battery 30 and an amount of electric power required for auxiliary machinery 34, and supplies required amounts of gases to the fuel cells 20 based on the estimated output electric current.

In a fuel-cells system 10 including a stack of fuel cells 20 and a storage battery 30, the remaining charge of the storage battery 30 is measured by a remaining charge monitor 46. In case that the observed remaining charge of the storage battery 30 is less than a predetermined reference value, a control unit 50 outputs a driving signal to an inverter 80, in order to restrict the consumption of electric power by a motor 32. When it is determined that the output state of the storage battery 30 is in the discharging state, based on the output electric current of the storage battery 30 measured by a current sensor 90, the control unit 50 further limits the electric power consumed by the motor 32. These processes are repeatedly carried out to charge the storage battery 30 and recover the remaining charge of the storage battery 30 to a sufficient level.

Growing community of inventors

Aichi-ken, Japan

Yasuhiro Nonobe