Patents by Inventor Keigo Ikezoe

Keigo Ikezoe has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8828612
    Abstract: The fuel cell system is simplified and made more compact while providing the favorable recirculation of hydrogen-containing off-gas regardless of the increase or decrease in its flow rate. The fuel cell system is provided with: a cell unit that generates electricity by means of separating hydrogen-containing gas and oxygen-containing gas from each other while placing in flow contact to each other; and a recirculation mechanism for recirculating to the cell unit hydrogen-containing off-gas discharged from the cell unit. The fuel cell system has a flow rate determination unit that determines whether or not the hydrogen-containing gas fed to the cell unit is less than a predetermined flow rate; and a gas feeding pressure varying mechanism that cause the pressure of the hydrogen-containing gas to vary to increase and decrease when it is determined that the hydrogen-containing gas fed to the cell unit is less than the predetermined flow quantity.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: September 9, 2014
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Keigo Ikezoe, Yasushi Ichikawa
  • Patent number: 8790836
    Abstract: A fuel cell system and method that enables warm-up power generation corresponding to the residual water volume in the fuel cell stack without using auxiliary devices for measuring the residual water volume in the fuel cell stack. A controller computes total generated electrical energy Q by integrating of the generated current detected by current sensor during the period from start-up to shutting down of the fuel cell system, and stores the result in total generated electrical energy storage part. Also, controller measures fuel cell temperature Ts at the last shutting down cycle with temperature sensor, and stores it in power generation shutting down temperature storage part.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: July 29, 2014
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Takahiro Kaito, Keigo Ikezoe
  • Publication number: 20140050998
    Abstract: A fuel cell system is provided with a plurality of cell units, a feeding channel, a bypass channel and a control unit. The cell units generate power by feeding hydrogen-containing gas an oxygen-containing gas separated from each other and then having them flow and join with each other. The feeding channel has an ejector arranged therein for refluxing exhausted hydrogen-containing gas exhausted from the cell units back to the cell units. The bypass channel has the hydrogen-containing gas flowing to the cell units bypass the ejector. The control unit includes a gas feeding pressure varying section that is programmed to make the hydrogen-containing gas flow in the bypass channel, and, at the same time, vary the pressure of the hydrogen-containing gas flowing in the feeding channel upon determining a flow rate of the hydrogen-containing gas flowing in the feeding channel is over a prescribed level.
    Type: Application
    Filed: November 2, 2011
    Publication date: February 20, 2014
    Applicant: Nissan Motor Co., Ltd.
    Inventors: Keigo Ikezoe, Yasushi Ichikawa
  • Publication number: 20130244127
    Abstract: A fuel cell system is basically provided with a fuel cell, a pressure adjusting valve, a purge valve and an anode pressure controller. The fuel cell includes an anode that receives an anode gas and a cathode that receives a cathode gas to generate electric power corresponding to a load. The pressure adjusting valve is disposed in a supply path to adjust anode gas pressure to the anode. The purge valve is disposed in a discharging flow path to discharge an anode-off gas containing impurities from the fuel cell. The anode pressure controller is configured to control the pressure adjusting valve to perform a pulsation operation that pulsates the anode gas pressure of the fuel cell. The anode pressure controller decreases a median pressure of the pulsation operation as a wetness level of an electrolyte membrane of the fuel cell stack is determined to become higher.
    Type: Application
    Filed: March 11, 2013
    Publication date: September 19, 2013
    Applicant: NISSAN MOTOR CO., LTD.
    Inventors: Susumu MAESHIMA, Keigo IKEZOE, Yasushi ICHIKAWA, Takahiro FUJII, Ryoichi SHIMOI, Taiji NISHIYAMA, Yusuke ITO
  • Publication number: 20130171531
    Abstract: The fuel cell system is simplified and made more compact while providing the favorable recirculation of hydrogen-containing off-gas regardless of the increase or decrease in its flow rate. The fuel cell system is provided with: a cell unit that generates electricity by means of separating hydrogen-containing gas and oxygen-containing gas from each other while placing in flow contact to each other; and a recirculation mechanism for recirculating to the cell unit hydrogen-containing off-gas discharged from the cell unit. The fuel cell system has a flow rate determination unit that determines whether or not the hydrogen-containing gas fed to the cell unit is less than a predetermined flow rate; and a gas feeding pressure varying mechanism that cause the pressure of the hydrogen-containing gas to vary to increase and decrease when it is determined that the hydrogen-containing gas fed to the cell unit is less than the predetermined flow quantity.
    Type: Application
    Filed: September 13, 2011
    Publication date: July 4, 2013
    Applicant: NISSAN MOTOR CO., LTD.
    Inventors: Keigo Ikezoe, Yasushi Ichikawa
  • Publication number: 20130164649
    Abstract: An anode gas non-recirculation type fuel cell system includes a fuel cell, a buffer tank for purging impurity gas included in anode off-gas from the fuel cell stack, an impurity gas concentration detector for detecting impurity gas concentration in the buffer tank, and an anode gas supply unit for supplying anode gas to the fuel cell stack. When pressure-supplying impurity gas in the fuel cell stack to the buffer tank while pulsating a supply pressure by the anode gas supply unit, an activation control is executed by changing, by the anode gas supply unit, at least one of a pulsative pressure and a pulsative cycle of anode gas supply according to impurity gas concentration in the buffer tank. According to the system, it is possible to get adequate hydrogen gas concentration in a fuel cell stack and to remove impurity at its activation.
    Type: Application
    Filed: September 1, 2011
    Publication date: June 27, 2013
    Inventors: Hidetaka Nishimura, Keigo Ikezoe, Masashi Sato
  • Publication number: 20130149627
    Abstract: Conventional fuel cell systems had the problem of impurity gases flowing back from a buffer tank and a reduction in the voltages of unit cells when the supply pressure of an anode gas is caused to pulsate at startup. An operating method include setting any one of the amplitude and cycle of the pulsation of the supply pressure of the anode gas to a fuel cell stack (FS) in accordance with the permeability of a nitrogen gas from a cathode side to an anode side. The method makes it possible to suppress unnecessary pulsation of the supply pressure of the anode gas at startup, and thus to maintain the concentration of a hydrogen gas in the fuel cell stack (FS) at an optimum level while preventing degradation in the mechanical strength of a membrane electrode structure that constitutes each unit cell (FC) of the fuel cell stack (FS).
    Type: Application
    Filed: September 27, 2011
    Publication date: June 13, 2013
    Inventors: Hidetaka Nishimura, Keigo Ikezoe, Masashi Sato
  • Publication number: 20130137003
    Abstract: A fuel cell system is provided with a fuel cell, a gas supply passage which supplies a reaction gas to the fuel cell, a humidifier which humidifies the reaction gas, a first gas discharge passage which leads from a first gas discharge outlet of the fuel cell through the humidifier to the outside, and a second gas discharge flow passage which leads from a second gas discharge outlet of the fuel cell to the outside. A flow rate control mechanism which controls the flow rate of discharge gas is provided in at least one of the first gas discharge passage and the second gas discharge passage. The configuration reduces the distance between the fuel cell and the humidifier to obtain a compact system structure.
    Type: Application
    Filed: June 21, 2011
    Publication date: May 30, 2013
    Applicant: NISSAN MOTOR CO., LTD.
    Inventors: Takahito Osada, Keigo Ikezoe, Hayato Chikugo
  • Publication number: 20130071769
    Abstract: Disclosed is a fuel cell provided with a membrane electrode structure having a frame, two separators that sandwich the membrane electrode structure therebetween, and gas seals between the end portion of the frame and the end portions of respective separators, and diffuser sections for distributing a reacting gas to between the frame and respective separators. In the diffuser section on the cathode side, the frame is provided with a protruding section in contact with the separator, and in the diffuser section on the anode side, the frame and the separator are disposed by being spaced apart from each other, thereby excellently maintaining contact surface pressure between the membrane electrode structure and the separators, and preventing contact resistance from being increased.
    Type: Application
    Filed: April 19, 2011
    Publication date: March 21, 2013
    Applicant: NISSAN MOTOR CO., LTD.
    Inventors: Keigo Ikezoe, Mitsutaka Abe, Takanori Oku, Yasuhiro Numao
  • Patent number: 8357473
    Abstract: When a stop trigger of a fuel cell system (100) is turned on, air humidified by a humidifier (3) which air having a humidity quantity lower than a humidity quantity at a normal operation is supplied to a fuel cell stack (11). Thereby, a takeout quantity Qm of a moisture generated in the fuel cell stack (1) is increased, then, a power generation of the fuel cell stack (1) is continued for a certain time Pg. Then, the power generation is stopped, and a cathode side of the fuel cell stack (1) is purged with the air for a certain time Pp.
    Type: Grant
    Filed: October 27, 2005
    Date of Patent: January 22, 2013
    Assignee: Nissan Motor Co., Ltd.
    Inventor: Keigo Ikezoe
  • Publication number: 20110274998
    Abstract: A fuel cell system 100 includes: a fuel cell 1 for generating a power by causing an electrochemical reaction between an oxidant gas supplied to an oxidant electrode 34 and a fuel gas supplied to a fuel electrode 67; a fuel gas supplier HS for supplying the fuel gas to the fuel electrode 67; and a controller 40 for controlling the fuel gas supplier HS to thereby supply the fuel gas to the fuel electrode 67, the controller 40 being configured to implement a pressure change when an outlet of the fuel electrode 67 side is closed, wherein based on a first pressure change pattern for implementing the pressure change at a first pressure width API, the controller 40 periodically changes a pressure of the fuel gas at the fuel electrode 67.
    Type: Application
    Filed: November 16, 2009
    Publication date: November 10, 2011
    Inventors: Yasushi Ichikawa, Keigo Ikezoe, Kenichi Goto, Ken Nakayama, Mitsunori Kumada, Yousuke Tomita
  • Publication number: 20100190071
    Abstract: A fuel cell system and method that enables warm-up power generation corresponding to the residual water volume in the fuel cell stack without using auxiliary devices for measuring the residual water volume in the fuel cell stack. A controller computes total generated electrical energy Q by integrating of the generated current detected by current sensor during the period from start-up to shutting down of the fuel cell system, and stores the result in total generated electrical energy storage part. Also, controller measures fuel cell temperature Ts at the last shutting down cycle with temperature sensor, and stores it in power generation shutting down temperature storage part.
    Type: Application
    Filed: June 18, 2008
    Publication date: July 29, 2010
    Inventors: Takahiro Kaito, Keigo Ikezoe
  • Publication number: 20100167144
    Abstract: A fuel cell system and a method for controlling the same. The system and method employ a fuel cell stack that generates electrical power by electrochemical reaction of a fuel gas and an oxidant gas, a total generated electrical energy computation device that computes a value pertaining to the total generated electrical energy as the sum of the electrical energy generated by said fuel cell stack from start-up of the fuel cell system, and a residual water volume estimation device that estimates the residual water volume left in the fuel cell stack based on said value pertaining to said total generated electrical energy computed by said total generated electrical energy computation device.
    Type: Application
    Filed: June 18, 2008
    Publication date: July 1, 2010
    Applicant: Nissan Motor Co., Ltd.
    Inventors: Takahiro Kaito, Keigo Ikezoe
  • Patent number: 7504831
    Abstract: A cell-voltage measuring structure for a fuel cell stack, in which a plurality of unit cells, having conductive separators which includes anode-side separators and cathode-side separators to form pairs of unit separators with the anode-side separators and the cathode-side separators adjacent to each other, respectively, are stacked in a stack direction, is provided with a voltage-measuring unit having a conductive voltage-measuring terminal, a contact section, with which the conductive voltage-measuring terminal is to be held in contact, formed on an outer periphery of a first pair of unit separators, a non-contact section, with which the conductive voltage-measuring terminal is not to be held in contact, formed on an outer periphery of a second pair of unit separators adjacent to the first pair of unit separators. A length of the conductive voltage-measuring terminal is greater than a thickness of the first pair of unit separators, in the stack direction.
    Type: Grant
    Filed: March 18, 2005
    Date of Patent: March 17, 2009
    Assignee: Nissan Motor Co., Ltd.
    Inventor: Keigo Ikezoe
  • Publication number: 20090047565
    Abstract: A separator (5, 6) for a fuel cell (1) comprises a gas passage (16-20, 36-40) facing an electrode (3, 4). The gas passage (16-20, 36-40) comprises a rapid expansion which enlarges a width of the gas passage (16-20, 36-40) in a step-like fashion from an upstream side to a downstream side with respect to a flow of gas. The gas passage (16-20, 36-40) upstream of the rapid expansion is thereby made narrow which prevents dry-out of the fuel cell (1) while the rapid expansion enhances a moisture bead sweeping force of the gas flow which prevents flooding from occurring in the gas passage (16-20, 36-40) downstream of the rapid expansion.
    Type: Application
    Filed: August 8, 2008
    Publication date: February 19, 2009
    Inventors: Takayuki TERASAKI, Keigo Ikezoe
  • Patent number: 7361425
    Abstract: A fuel cell has an anode electrode (3), a cathode electrode (5), the membrane electrolyte (4) sandwiched by the anode and cathode electrodes, two separators (1, 7), a first current collector (2) and a second current collector (6). The two separators (1, 7) each having a flat plate-shaped porous body are disposed to sandwich the two electrodes. The two separators are water permeable. The first current collector (2) is disposed between the anode electrode and one separator, the first current collector forming a first gas channel allowing flow of the fuel gas. The second current collector (6) is disposed between the cathode electrode and the other separator, the second current collector forming a second gas channel allowing flow of the gaseous oxidant.
    Type: Grant
    Filed: March 18, 2003
    Date of Patent: April 22, 2008
    Assignee: Nissan Motor Co., Ltd.
    Inventor: Keigo Ikezoe
  • Publication number: 20080020246
    Abstract: When a stop trigger of a fuel cell system (100) is turned on, air humidified by a humidifier (3) which air having a humidity quantity lower than a humidity quantity at a normal operation is supplied to a fuel cell stack (11). Thereby, a takeout quantity Qm of a moisture generated in the fuel cell stack (1) is increased, then, a power generation of the fuel cell stack (1) is continued for a certain time Pg. Then, the power generation is stopped, and a cathode side of the fuel cell stack (1) is purged with the air for a certain time Pp.
    Type: Application
    Filed: October 27, 2005
    Publication date: January 24, 2008
    Inventor: Keigo Ikezoe
  • Publication number: 20050287416
    Abstract: A fuel cell is provided with a membrane electrode assembly (26) in which an anode (26B) and a cathode (26C) are formed on both sides of a polymer electrolyte film (26A). The fuel cell is provided with a downstream gas supply channel (33) facing the cathode (26C), an upstream gas supply channel (32) through which a cathode gas is supplied to the downstream gas supply channel (33) and which does not face the cathode (26C), and a partition wall (28A) which is made from a porous material and partitions the downstream gas supply channel (33) and the upstream gas supply channel (32). Electro-chemical reactions of the cathode gas in the cathode (26C) generates a large amount of moisture. The moisture passes through the partition wall (26A) and humidifies the cathode gas of the upstream gas supply channel (32), thereby making the moisture distribution in the membrane electrode assembly (26) uniform.
    Type: Application
    Filed: August 22, 2003
    Publication date: December 29, 2005
    Inventor: Keigo Ikezoe
  • Publication number: 20050255365
    Abstract: A fuel cell has an anode electrode (3), a cathode electrode (5), the membrane electrolyte (4) sandwiched by the anode and cathode electrodes, two separators (1, 7), a first current collector (2) and a second current collector (6). The two separators (1, 7) each having a flat plate-shaped porous body are disposed to sandwich the two electrodes. The two separators are water permeable. The first current collector (2) is disposed between the anode electrode and one separator, the first current collector forming a first gas channel allowing flow of the fuel gas. The second current collector (6) is disposed between the cathode electrode and the other separator, the second current collector forming a second gas channel allowing flow of the gaseous oxidant.
    Type: Application
    Filed: March 18, 2003
    Publication date: November 17, 2005
    Inventor: Keigo Ikezoe