Nissan Motor Company Limited

Tokyo Radiator Mfg. Co., Ltd.

Nippon Yakin Kogyo Co., Ltd.

Masatoshi Iio

Yutaka Kobayashi

Takashi Fukuda

Keisuke Suzuki

Hitoshi Igarashi

Yasukazu Iwasaki

Kenji Yonekura

Mituo Kimura

Takao Izumi

Hayato Chikugo

Kazuo Saito

Mitsunori Kumada

Ikuhiro Taniguchi

Takashi Iimori

Masaru Okamoto

Naoto Todoroki

Koichi Yamaguchi

Shinichi Makino

Hisashi Niioka

Takatada Usami

Yoshito Fujiwara

Atsushi Ooma

Seiho Sugawara

Takanori Hiyoshi

Mitsuhiro Kokubo

Yoshinao Ootake

Tohsaku Takamura

Naoto c/o Nissan Motor Co Ltd Todoroki

Ikuhiro c/o Nissan Motor Co Ltd Taniguchi

Hitoshi c/o Nissan Motor Co Ltd Igarashi

Yoshinao c/o Nissan Motor Co Ltd Ootake

A fuel cell stack includes a heat exchange unit that performs heat exchange between a gas mixture containing source hydrogen and a circulating gas and cooling water used for controlling the temperature of the fuel cell stack. A system controller adjusts the temperature of the cooling water by controlling a temperature control unit on the basis of the temperature of source hydrogen flowing into a junction at which the source hydrogen and a circulating gas are mixed such that the temperature of a source/recirculated hydrogen mixture that is mixed at the junction and that is supplied to the fuel cell stack is kept within a managed temperature range.

Fuel cell system and method of controlling fuel cell system

A fuel cell system includes a controller that estimates or detects an air replacement state of a fuel electrode and a hydrogen circulation path while the operation of the fuel cell system is stopped. Upon starting the fuel cell system, the controller changes the order in which the operation of a hydrogen circulation pump is started and a hydrogen pressure regulator is opened to start the supply of hydrogen gas on the basis of the estimated or detected air replacement state, thereby preventing deterioration caused by uneven distribution of air and hydrogen in the fuel electrode.

Fuel cell system

A fuel cell has an anode, a cathode, and a proton-exchange membrane disposed between the anode and cathode. An exhaust anode gas exhausted from an outlet of the anode is directed back to an inlet of the anode. Hydrogen is added to the exhaust anode gas before the exhaust anode gas reaches the inlet.

Fuel cell start-up control system

Moisture caused by humidity in the fuel gas and water vapor from the water that is generated become condensed inside a fuel cell when power generation in the fuel cell is temporarily stopped, making obstruction to the fuel gas flow channel when power generation is restarted possible. A fuel cell includes an electrolyte membrane sandwiched between a fuel electrode and an oxidant electrode. Oxidant is supplied to the oxidant electrode in the fuel cell, and the fuel emitted from the fuel electrode of the fuel cell is resupplied back to the fuel electrode. When requested power generating capacity for the fuel cell is less than a prescribed capacity, the oxidant supply is temporarily stopped while the fuel continues to circulate in order to prevent obstruction in the fuel flow channel due to water condensation, making a reliable fuel supply becomes possible.

Fuel cell with anode exhaust recirculation means

A fuel cell stack () performs power generation using an anode gas having hydrogen as its main component, and after a power generation reaction, the anode gas is discharged as anode effluent. The anode effluent is re-circulated into the anode gas through a return passage (). The return passage () comprises a purge valve () which discharges the anode effluent to the outside of the passage. In this invention, calculation of a first energy loss caused by an increase in non-hydrogen components in the anode gas while the purge valve () is closed (S, S), and calculation of a second energy loss which corresponds to the amount of hydrogen lost from the anode gas by opening the purge valve () (S, S) are performed. By opening the purge valve () when the second energy loss equals or falls below the first energy loss, the start timing of purging is optimized.

Anode effluent control in fuel cell power plant

A system controller drives a gas circulator with a purge valve closed to supply hydrogen to a fuel cell stack and then increases anode operating pressure and cathode operating pressure to target operating pressures after a predetermined condition is satisfied. This allows an amount of gas mixture of remaining oxygen and hydrogen to be suppressed compared to the case of increasing the anode operating pressure in a state where oxygen remains in the anode circulation path. Accordingly, it is possible to suppress local generation of electric potential and heat and prevent degradation of the components of the fuel cell stack. Moreover, hydrogen is not discharged during activation, which eliminates the need to include dilution equipment of combustion equipment for treating hydrogen and increases the degree of freedom in the layout of the fuel cell system.

In a fuel cell power plant, carbon monoxide contained in reformate gas which is produced by a reformer () by means of a catalytic fuel reaction is removed by the respective catalytic reactions of a shift converter () and a preferential oxidation reactor (). During start up of the fuel cell power plant, a burner () burns fuel to produce combustion gas and the combustion gas is supplied individually to the reformer (), shift converter () and preferential oxidation reactor () through combustion gas supply passages (-) thereby simultaneously completing warming up of these catalytic reactors (-).

Fuel cell power plant warm up

A fuel reforming system generates burnt gas by burning fuel and air in a burner () during system startup, and the temperatures of a reforming reactor () and carbon monoxide oxidizer () are raised by supplying the burnt gas to the reforming reactor () and carbon monoxide oxidizer (). The temperature of the burnt gas produced by the burner () is increased according to the elapsed time from the beginning of the startup processing.

Fuel reforming system and warmup method thereof

The fuel cell system according to this invention disposes a moisture exchanger () at a suction side of an air supply device (). This causes an increase in the pressure differential and temperature differential of the fresh air and the cathode exhaust in the moisture exchanger () and promotes transfer of moisture. Since the moisture exchanger () effectively transfers moisture, it is possible to downsize the radiator for the cooling water and the condenser (). Thus it is possible to reduce the weight and size of the fuel cell system.

A vehicle fuel cell system according to this invention comprises a controller () that compares a input running distance to a predetermined distance. When the input running distance is less than the predetermined distance, the controller () finishes running using only the hydrogen supplied from a hydrogen storage device () without starting a start-up combustor (). When the input running distance is larger than the predetermined distance, the controller () starts hydrogen supply from the hydrogen storage device (), and simultaneously starts warm-up of a reformer () by starting the start-up combustor (). When warm-up of the reformer () is complete, supply of hydrogen from the hydrogen storage device () finishes, and hydrogen supply from the reformer () starts.

Fuel cell system for vehicle

The hydrogen permeating to a post-separation side (B) of the membrane hydrogen separator () is supplied to an anode chamber (A) of a fuel cell stack () via a hydrogen supply passage (). A hydrogen recirculation passage () recirculates hydrogen from the anode chamber (A) to the post-separation side (B). When the hydrogen partial pressure on the post-separation side (B) increases, air is introduced into the hydrogen recirculation passage () from an intake valve (). When the hydrogen partial pressure decreases, gas in the hydrogen recirculation passage () is discharged from an exhaust valve (). The rate of hydrogen permeation through the membrane hydrogen separator () is thereby maintained to a preferred level.

Fuel cell power plant

A reformer ( ) produces a reformate gas by partial oxidation of vaporized fuel with air supplied through a first air supply passage ( A). A hydrogen-rich gas is produced by removing carbon monoxide from the reformate gas with a carbon monoxide oxidizer ( ) and thereafter is supplied to the fuel cell stack ( ). A second air supply passage ( A) which has a smaller cross sectional area than the first air supply passage ( A) is also provided to supply air to the reformer ( ). When substantially no load is applied to the fuel cell stack ( ), the first air supply passage ( A) is cut off with a valve ( A) and a minute amount of air is supplied to the reformer ( ) from the second air supply passage ( A) to maintain a standby operation of the power plant in order to prevent reductions in the temperature of the fuel cell stack ( ).

In a fuel cell system and a method of controlling the same, a fuel cell stack is connected at its downstream side with a hydrogen control valve and a hydrogen draw pump . A control unit controls the hydrogen draw pump such that hydrogen drawing power is increased to a level larger than that required for normal operation and controls the hydrogen control valve such that opening degree is decreased. After that, the control unit controls the hydrogen control valve such that the opening degree is increased to purge moisture in the fuel cell stack.

Fuel cell system and method

A fuel cell generation system of the invention includes a reforming apparatus; a fuel cell; a reformed gas flow rate control section controlling a flow rate of reformed gas flowing from the reforming apparatus so that an operating pressure of the reforming apparatus is equal to its target pressure; a reformed gas flow rate detecting section detecting a flow rate of the reformed gas flowing into the fuel cell; a target load current calculating section calculating a target load current taken out of the fuel cell in accordance with the flow rate of the reformed gas detected by the reformed gas flow rate detecting section so that an operating pressure of the fuel cell is equal to its target pressure; an inlet pressure detecting section detecting an inlet pressure of the fuel cell; a target load current correction quantity calculating section calculating a load current correction quantity in accordance with a deviation between the inlet pressure of the fuel cell detected by the inlet pressure detecting section and the target pressure of the fuel cell; and a correction quantity adding section adding the target load current calculated by the target load current calculating section and the load current correction quantity calculated by the target load current correction quantity calculating section.

Fuel cell generation system

A ferritic stainless steel comprises C: not more than 0.025 wt %, Si: not more than 0.10 wt %, Mn: not more than 1.0 wt %, Cr: 17.0-25.0 wt %, Ni: not more than 0.50 wt %, Mo: 0.50-2.00 wt %, Al: not more than 0.025 wt %, N: not more than 0.025 wt %, at least one of Nb: 10(C wt %+N wt %)-1.0 wt % and Ti: 10(C wt %+N wt %)-1.0 wt %, and the balance being substantially Fe and inevitable impurities and is effectively used in various heat exchangers.

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Yokosuka, Japan

Masatoshi Iio