Patents by Inventor Koji Takahata

Koji Takahata 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: 9312568
    Abstract: A lithium secondary battery 10 of the present invention is a secondary battery provided with a positive electrode 30 having a positive electrode active material layer 34 on a positive electrode collector 32, and a negative electrode 50 having a negative electrode active material layer 54 on a negative electrode collector 52. The positive electrode active material layer 34 contains a positive electrode active material capable of reversibly storing and releasing lithium ions. The negative electrode active material layer 54 contains a negative electrode active material made up of lamellar graphite that is bent so as to have an average number of bends f per particle of 0<f?3, and an average aspect ratio of 1.8 or higher.
    Type: Grant
    Filed: December 21, 2011
    Date of Patent: April 12, 2016
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Koji Takahata, Hideki Sano
  • Patent number: 9312559
    Abstract: A main object of the present invention to provide a nonaqueous electrolyte secondary battery having high durability towards charge and discharge cycles, by preventing buckling of a wound electrode body. The secondary battery provided by the present invention comprises: a nonaqueous electrolyte; and a wound electrode body 80 configured by superposing on each other, and winding a positive electrode sheet 10 having a positive electrode collector formed to a sheet shape and a positive electrode active material layer formed on that collector, a, negative electrode sheet 20 having a negative electrode collector formed to a sheet shape and a negative electrode active material layer formed on that collector, and a separator 40 formed to a sheet shape. The negative electrode active material contained in the negative electrode active material layer is oriented in a predetermined direction.
    Type: Grant
    Filed: September 22, 2010
    Date of Patent: April 12, 2016
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Koji Takahata, Toshihiko Mitsuhashi, Naoyuki Wada
  • Patent number: 9281513
    Abstract: A lithium-ion secondary battery (100A) has a negative electrode current collector (241A) and a negative electrode active material layer (243A) formed on the negative electrode current collector (241A). The negative electrode active material layer (243A) contains a graphite material and a binder. The negative electrode active material layer (243A) has a first region (A1) neighboring the negative electrode current collector (241A), and the first region (A1) contains natural graphite in a weight ratio of equal to or greater than 80% of the graphite material. The negative electrode active material layer (243A) has a second region (A2) neighboring a surface thereof, and the second region (A2) contains artificial graphite in a weight ratio of equal to or greater than 80% of the graphite material.
    Type: Grant
    Filed: July 29, 2011
    Date of Patent: March 8, 2016
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Koji Takahata
  • Patent number: 9240701
    Abstract: A lithium-ion secondary battery (100) includes a positive electrode mixture layer (223) coated on a positive electrode current collector (221), a negative electrode mixture layer (243) coated on a negative electrode current collector (241), and an electrolyte solution containing lithium ions at a predetermined concentration. The number of lithium ions X in the electrolyte solution impregnated per 1 cm3 of the positive electrode mixture layer (223) and the number of lithium ions Y in the electrolyte solution impregnated per 1 cm3 of the negative electrode mixture layer (243) are both 3.75×1019 or greater.
    Type: Grant
    Filed: June 8, 2011
    Date of Patent: January 19, 2016
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Koji Takahata
  • Patent number: 9219278
    Abstract: The non-aqueous electrolyte secondary battery provided by this invention comprises a positive electrode and a negative electrode, wherein the positive electrode has a positive electrode active material layer comprising a positive electrode active material as a primary component, and the negative electrode has a negative electrode active material layer comprising a negative electrode active material as a primary component, having a negative electrode active material's linseed oil absorption number B (mL/100 g) to positive electrode active material's DBP absorption number A (mL/100 g) ratio B/A of 1.27 to 1.79.
    Type: Grant
    Filed: October 20, 2011
    Date of Patent: December 22, 2015
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Koji Takahata, Akihiro Ochiai
  • Patent number: 9190632
    Abstract: A power storage device includes a fuel cell (33), a battery holder (1) and an end plate (40) for sandwiching and binding the fuel cell, and an interposed member (11) disposed between the end plate (40) and the fuel cell (33). The battery holder (1) and the end plate (40) are made of resin, and have a positive coefficient of thermal expansion at a temperature lower than a predetermined temperature. The interposed member (11) is formed to have a substantially negative coefficient of thermal expansion at a temperature lower than the predetermined temperature.
    Type: Grant
    Filed: April 3, 2008
    Date of Patent: November 17, 2015
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Akira Tsujiko, Koji Takahata, Hironori Harada, Hideyasu Kawai, Hideyuki Yamamura
  • Patent number: 9190661
    Abstract: A secondary battery is provided with a negative electrode sheet including a negative active material layer including negative active material particles. The negative active layer contains, as the negative active material particles, graphite particles formed from graphite and amorphous carbon particles formed from amorphous carbon. The difference (?S)(=Sb?Sa) in specific surface area between the specific surface area (Sb) of the amorphous carbon particles and the specific surface area (Sa) of the graphite particles is ?0.3 to 2.6 m2/g.
    Type: Grant
    Filed: May 10, 2011
    Date of Patent: November 17, 2015
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Koji Takahata
  • Publication number: 20150221946
    Abstract: The present invention provides a negative electrode capable of improving the on-vehicle service life and storage life of a nonaqueous electrolyte secondary battery, a nonaqueous electrolyte secondary battery, and methods for manufacturing them. Provided is a negative electrode (32) used for a lithium-ion secondary battery (1) as a nonaqueous electrolyte secondary battery, including a negative electrode active material made of natural graphite whose surface is coated with amorphous carbon. The negative electrode active material has an electrostatic capacity of not less than 0.122 F/g and not more than 0.160 F/g, and a content percentage of the amorphous carbon of not less than 4 wt % and not more than 7 wt %.
    Type: Application
    Filed: April 25, 2013
    Publication date: August 6, 2015
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Koji Takahata
  • Publication number: 20150171414
    Abstract: A method is provided for manufacturing a lithium secondary battery, wherein a negative electrode composite material layer formed on a negative electrode in this battery has a maximum point, in accordance with measurement of the pore distribution based on a mercury intrusion technique, in the pore diameter range (A) of from at least 0.3 ?m to not more than 4 ?m and in the pore diameter range (B) of from at least 0 ?m to less than 0.3 ?m, and has a ratio (VA/VB) between the pore volume (VA) at the maximum point in the range A and the pore volume (VB) at the maximum point in the range B of from at least 2.1 to not more than 3.4.
    Type: Application
    Filed: December 2, 2011
    Publication date: June 18, 2015
    Inventors: Koji Takahata, Kaoru Inoue
  • Patent number: 9059436
    Abstract: A method for producing a lithium-ion secondary battery comprising positive and negative electrodes and a non-aqueous electrolyte solution is provided. The method comprises (A) with several different negative electrode active materials, determining density Xn (g/cm3) at several different number of taps applied, n, respectively; (B) determining density Y (g/cm3) of a negative electrode active material layer constituted with a mixture comprising each negative electrode active material; (C) based on a regression line, Y=aXn+b, determining the number of taps applied, n?, that gives a?0.5 and a determination coefficient R2?0.99; (D) based on a plot of Y=aXn?+b, determining a passing range of Xn? where negative electrode active material layer density Y is in a prescribed range; (E) selecting a negative electrode active material having Xn?in the passing range, and fabricating a negative electrode with this material.
    Type: Grant
    Filed: October 27, 2010
    Date of Patent: June 16, 2015
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Koji Takahata, Hideki Sano
  • Patent number: 8980482
    Abstract: The present invention provides a lithium-ion secondary battery with excellent high-temperature storage characteristics. The lithium-ion secondary battery provided by the present invention has positive and negative electrodes capable of absorbing and desorbing lithium ions, and an electrolyte solution containing a lithium salt as a supporting salt in an organic solvent. The nonaqueous electrolyte contains not only the lithium salt, but also at least one type of dicarboxylic acid as additive A; and at least one type of additive selected from vinylene carbonate, vinylethylene carbonate, ethylene sulfite, and fluoroethylene carbonate as additive B.
    Type: Grant
    Filed: August 24, 2009
    Date of Patent: March 17, 2015
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Koji Takahata
  • Publication number: 20150030931
    Abstract: The non-aqueous electrolyte secondary battery 10 provided by the present invention comprises a positive electrode 30, a negative electrode 50 and a non-aqueous electrolyte. The negative electrode 50 includes a negative electrode current collector 52 and a negative electrode active material layer 54 formed on the current collector 52, the negative electrode active material layer 54 containing a negative electrode active material 55 capable of storing and releasing charge carriers and having shape anisotropy so that the charge carriers are stored and released along a predefined direction. The negative electrode active material layer 54 includes, at a bottom thereof contacting the current collector 52, a minute conductive material 57 with granular shape and/or minute conductive material 57 with fibrous shape having an average particle diameter that is smaller than that of the negative electrode active material 55, and includes, at the bottom thereof; a part of the negative electrode active material 55.
    Type: Application
    Filed: December 14, 2011
    Publication date: January 29, 2015
    Inventors: Koji Takahata, Tatsuya Hashimoto, Yoshiyuki Ozaki, Yukihiro Okada, Kenji Tsuchiya, Masanori Kitayoshi, Naoyuki Wada
  • Patent number: 8936875
    Abstract: In a lithium ion secondary battery, an electrode assembly, in which a positive electrode sheet having a positive electrode mixture layer and a negative electrode sheet having a negative electrode mixture layer are overlain each other, is housed in a container together with a nonaqueous electrolyte solution. The negative electrode mixture layer includes a carbon material having at least in part a graphite structure as a negative active material.
    Type: Grant
    Filed: December 16, 2009
    Date of Patent: January 20, 2015
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Koji Takahata, Hideki Sano
  • Publication number: 20150010784
    Abstract: The present invention provides a sealed nonaqueous electrolyte secondary battery which is equipped with a current interrupt device that is actuated by a rise in internal pressure of a battery case and in which the current interrupt device is actuated in a speedy and stable manner during an overcharge. In the sealed nonaqueous electrolyte secondary battery, an electrode body formed by a positive electrode 10 and a negative electrode that oppose each other via a separator, an electrolyte, and an overcharge inhibitor are housed in the battery case. The positive electrode 10 includes a positive electrode current collector 12 and a positive electrode active material layer 14 which is formed on the current collector and which mainly contains a positive electrode active material. In addition, a conductive material layer 16 which mainly contains a conductive material is formed between the positive electrode active material layer 14 and the separator.
    Type: Application
    Filed: January 29, 2013
    Publication date: January 8, 2015
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Koji Takahata, Akihiro Ochiai
  • Patent number: 8911906
    Abstract: There is provided a lithium ion secondary cell excellent in charging and discharging cycle characteristics. A lithium ion secondary cell includes: an electrode body including a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material, and a separator; and a non-aqueous electrolyte containing a lithium salt as a supporting salt in an organic solvent, the electrode body and the non-aqueous electrolyte being accommodated in a case. The positive electrode active material is a lithium transition metal oxide having a layered structure. The electrolyte contains a compound represented by a chemical formula (I) in an amount of ? mol relative to the total content ? mol of moisture to be mixed in the cell. ? satisfies ?1.3?log(?/?)?1.
    Type: Grant
    Filed: August 4, 2009
    Date of Patent: December 16, 2014
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Koji Takahata, Yukihiro Okada
  • Publication number: 20140349189
    Abstract: A lithium secondary battery 10 of the present invention is a secondary battery provided with a positive electrode 30 having a positive electrode active material layer 34 on a positive electrode collector 32, and a negative electrode 50 having a negative electrode active material layer 54 on a negative electrode collector 52. The positive electrode active material layer 34 contains a positive electrode active material capable of reversibly storing and releasing lithium ions. The negative electrode active material layer 54 contains a negative electrode active material made up of lamellar graphite that is bent so as to have an average number of bends f per particle of 0<f?3, and an average aspect ratio of 1.8 or higher.
    Type: Application
    Filed: December 21, 2011
    Publication date: November 27, 2014
    Inventors: Koji Takahata, Hideki Sano
  • Publication number: 20140335389
    Abstract: A battery, which is provided with a pressure-type current interrupt mechanism, is provided with: a gas-generating material placed outside an electrode body and within a battery case; a positive electrode potential member that is placed outside the electrode body and within the battery case in a manner contacting the gas-generating material, and conducts with the positive electrode of the electrode body; and a negative electrode potential member that is placed outside the electrode body and within the battery case in a manner contacting the gas-generating material while being spaced from the positive electrode potential member, and conducts with the negative electrode of the electrode body. The gas-generating material includes a gas-generating agent that generates a gas when the potential of the positive electrode potential member exceeds a gas generation potential.
    Type: Application
    Filed: December 19, 2011
    Publication date: November 13, 2014
    Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventor: Koji Takahata
  • Publication number: 20140312684
    Abstract: A power supply apparatus comprises: a transformer that includes primary/secondary windings that are electromagnetically connected to each other with polarities opposite to each other, an output switch that activates/inactivates an electric-current route that extends from an application terminal for an input voltage to a ground terminal via the primary winding a rectifying-smoothing portion that generates an output voltage from an induced voltage, a feedback voltage generation portion that monitors a switch voltage appearing at a connection node between the primary winding and the output switch and generates a feedback voltage in accordance with the output voltage, a reference voltage generation portion that generates a reference voltage, a comparator that compares the feedback voltage and the reference voltage with each other to generate a comparison signal, and a switching control portion that generates an output switch control signal by means of an on-time control method in accordance with the comparison si
    Type: Application
    Filed: March 26, 2014
    Publication date: October 23, 2014
    Applicant: ROHM CO., LTD.
    Inventors: Hiroshi Sawada, Satoshi Oishi, Koji Takahata, Yohei Akamatsu
  • Publication number: 20140272540
    Abstract: A nonaqueous secondary battery 100A has a negative electrode sheet 240A in which a negative electrode active material layer 243A is held by a negative electrode current collector 241A. Contained within the negative electrode active material layer 243A is a binder 730 which includes a rubber-based binder or a resin having a binder function. The rubber-based binder or the resin having a binder function is abundantly present, within the negative electrode active material layer 243A, in a surface vicinity A1 of the negative electrode active material layer 243A.
    Type: Application
    Filed: October 11, 2011
    Publication date: September 18, 2014
    Inventors: Koji Takahata, Machiko Abe, Akihiro Ochiai
  • Publication number: 20140255783
    Abstract: The non-aqueous electrolyte secondary battery provided by this invention comprises a positive electrode and a negative electrode, wherein the positive electrode has a positive electrode active material layer comprising a positive electrode active material as a primary component, and the negative electrode has a negative electrode active material layer comprising a negative electrode active material as a primary component, having a negative electrode active material's linseed oil absorption number B (mL/100 g) to positive electrode active material's DBP absorption number A (mL/100 g) ratio B/A of 1.27 to 1.79.
    Type: Application
    Filed: October 20, 2011
    Publication date: September 11, 2014
    Inventors: Koji Takahata, Akihiro Ochiai