Patents by Inventor Takefumi Okumura

Takefumi Okumura 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).

  • Publication number: 20120100436
    Abstract: Disclosed is a lithium-ion secondary battery which includes a carbonaceous material in an anodic active material mix, and a cyclic carbonate and a chain carbonate both in an electrolytic solution. The solvent contains an additive which is a substance having a LUMO energy determined through molecular orbital calculation of lower than the LUMO energy of ethylene carbonate determined through molecular orbital calculation and having a HOMO energy lower than the HOMO energy of vinylene carbonate determined through molecular orbital calculation, the electrolytic solution contains LiPF6 or LiBF4 as an electrolyte, and the electrolytic solution shows a reduction-reaction current of ?0.05 mA/cm2 (provided that a reaction current on the reducing side be negative) or less at a potential lower than 1 V and shows an oxidation-reaction current of 0.5 mA/cm2 (provided that a reaction current on the oxidizing side be positive) or more at a potential higher than 5.
    Type: Application
    Filed: June 21, 2010
    Publication date: April 26, 2012
    Inventors: Ryo Inoue, Shigetaka Tsubouchi, Takefumi Okumura
  • Publication number: 20120081077
    Abstract: A rechargeable battery system that controls charge/discharge of a lithium ion rechargeable battery, includes: an internal resistance detection unit that detects or estimates an internal resistance value indicating an internal resistance at the lithium ion rechargeable battery; and a discharge control unit that executes control so as to set a discharge suspension period while the lithium ion rechargeable battery is discharged if the internal resistance value detected via the internal resistance detection unit during discharge of the lithium ion rechargeable battery exceeds a first threshold value.
    Type: Application
    Filed: September 8, 2011
    Publication date: April 5, 2012
    Applicant: Hitachi, Ltd.
    Inventors: Hironori SASAKI, Tsunenori Yamamoto, Takefumi Okumura
  • Publication number: 20110195319
    Abstract: The object of the present invention is to provide a lithium secondary battery which can suppress a deterioration for a period of high temperature storage at 50° C. or more. The present invention relates to a lithium secondary battery comprising a positive electrode which can occlude and discharge lithium ion, a negative electrode which can occlude and discharge lithium ion, a separator which is disposed between the positive electrode and the negative electrode, and an electrolyte, wherein the electrolyte includes a compound within whose molecule a plurality of polymerizable functional groups are included. Herein, the electrolyte can comprise a compound represented by the formula 3: wherein each of Z1 and Z2 represents a polymerizable functional group including any one selected from the group consisting of allyl group, methallyl group, vinyl group, acryl group and methacryl group.
    Type: Application
    Filed: February 9, 2011
    Publication date: August 11, 2011
    Inventors: Takefumi OKUMURA, Ryo INOUE
  • Publication number: 20110187312
    Abstract: Provided is a secondary battery system including: a battery controller which controls charge and discharge of a secondary battery; a total controller which controls the entire system; an ammeter which detects a charge current and a discharge current of the secondary battery; and a voltmeter which detects a voltage of the secondary battery, in which a direct current resistance of the secondary battery at the time of charge and a direct current resistance of the secondary battery at the time of discharge are obtained on the basis of a current value and a voltage value detected by the ammeter and the voltmeter, to thereby determine a temporary increase in the direct current resistance of the secondary battery caused by charge and discharge with a large current on the basis of a relation between the two obtained direct current resistances.
    Type: Application
    Filed: January 28, 2011
    Publication date: August 4, 2011
    Inventors: Tsunenori YAMAMOTO, Takefumi Okumura, Hironori Sasaki
  • Publication number: 20110183213
    Abstract: An object of the present invention is to provide a lithium ion battery in which the deterioration during the high temperature storage is suppressed. The lithium ion battery is a lithium ion battery 100 having a cathode 3 capable of occluding and releasing lithium ions, an anode 6 capable of occluding and releasing lithium ions, a separator 7 disposed between the cathode 3 and the anode 6 and an organic electrolyte solution, wherein the organic electrolyte solution contains a plurality of solvents, an additive and an electrolyte, the electrolyte contains lithium hexafluorophosphate (LiPF6), and the additive contains vinylene carbonate or a derivative thereof and a compound represented by the following formula (I): wherein R1, R2 and R3 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 3 carbon atoms.
    Type: Application
    Filed: January 11, 2011
    Publication date: July 28, 2011
    Inventors: Ryo INOUE, Takefumi OKUMURA
  • Publication number: 20110171501
    Abstract: This invention provides a lithium-ion battery in which a coating film forming agent degradation reaction is prevented. A lithium-ion battery 100 in which electrodes 1 and 2 and an electrolyte are accommodated in a battery container 13, and which has a means of for adding a coating film forming agent 20 for adding a coating film forming agent 21 that forms a coating film on the surface of each of electrodes 1 and 2 to an electrolyte in a battery container 13 is provided. With the use of such means of adding a coating film forming agent 20, a reaction of electrochemical degradation of a coating film forming agent 21 is prevented, allowing long-term preservation. Also, with the addition of a coating film forming agent 21 to an electrolyte, a deteriorated coating film on the surface of each of electrodes 1 and 2 is repaired such that a lithium-ion battery 100 can be regenerated, resulting in extension of battery life.
    Type: Application
    Filed: January 11, 2011
    Publication date: July 14, 2011
    Inventors: Takefumi Okumura, Ryo Inoue, Toshio Abe
  • Publication number: 20110171525
    Abstract: Disclosed are an electrode for a lithium secondary battery which includes a metal substrate and a plated layer arranged on the metal substrate and bearing active material particles and resin particles embedded therein, in which a part of the active material particles and the resin particles has a protruding portion beyond the plated layer; and a lithium secondary battery using the electrode. The electrode helps the lithium secondary battery to be resistant to deterioration and property degradation at high temperature and allows the battery to have high input-output performance and to be suitable typically for hybrid electric vehicles.
    Type: Application
    Filed: January 12, 2011
    Publication date: July 14, 2011
    Inventors: Toshio ABE, Takefumi Okumura
  • Publication number: 20110143196
    Abstract: Objects of the present invention are to improve the adhesion and processing characteristics of electrode composite layers and to provide a lithium secondary battery by which a decrease in battery capacity during high-temperature storage at 50° C. or higher is suppressed. The lithium secondary battery of the present invention comprises a positive electrode capable of storing and releasing lithium ions, a negative electrode capable of storing and releasing lithium ions, a separator disposed between the positive electrode and the negative electrode, and an electrolyte, wherein the negative electrode or the electrolyte contains a nonvolatile liquid.
    Type: Application
    Filed: December 7, 2010
    Publication date: June 16, 2011
    Inventors: Takefumi OKUMURA, Ryo Inoue, Toshio Haba, Chieko Araki
  • Patent number: 7923580
    Abstract: A polymerizable boric compound for electrochemical devices represented by the formula (1), wherein, B represents a boron atom, Z represents a polymerizable functional group, X represents a divalent C1-12 hydrocarbon group or in the absence of X, Z and B form a direct bond, AO represents a C2-4 oxyalkylene group, m and n are each the number of moles of the oxyalkylene group added and each independently stands for 2 or greater but less than 6, and R1 and R2 each represents a C1-12 hydrocarbon group.
    Type: Grant
    Filed: March 22, 2010
    Date of Patent: April 12, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Norio Iwayasu, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
  • Patent number: 7862933
    Abstract: The present invention provides a lithium secondary battery which has improved safety, mainly coming from use of an electrolyte solution which is not inflammable at room temperature (20° C.), while not deteriorating output characteristics at low temperatures and room temperature or output maintenance characteristics after storage at high temperature (50° C.). The lithium secondary battery of the present invention, encased in a container, is provided with a cathode and an anode, both capable of storing/releasing lithium ions, a separator which separates these electrodes from each other, and an electrolyte solution containing a cyclic carbonate and a linear carbonate as solvents and a compound such as VC at composition ratios of 18.0 to 30.0%, 74.0 to 81.9% and 0.1 to 1.0%, respectively, based on the whole solvents, all percentages by volume.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: January 4, 2011
    Assignee: Hitachi Vehicle Energy, Ltd.
    Inventors: Takefumi Okumura, Takahiro Yamaki, Masanori Yoshikawa, Yoshimi Yanai, Toyotaka Yuasa
  • Publication number: 20100297509
    Abstract: The present invention provides a lithium secondary battery which has improved safety, mainly coming from use of an electrolyte solution which is not inflammable at room temperature (20° C.), while not deteriorating output characteristics at low temperatures and room temperature or output maintenance characteristics after storage at high temperature (50° C.). The lithium secondary battery of the present invention, encased in a container, is provided with a cathode and an anode, both capable of storing/releasing lithium ions, a separator which separates these electrodes from each other, and an electrolyte solution containing a cyclic carbonate and a linear carbonate as solvents and a compound such as VC at composition ratios of 18.0 to 30.0%, 74.0 to 81.9% and 0.1 to 1.0%, respectively, based on the whole solvents, all percentages by volume.
    Type: Application
    Filed: August 3, 2010
    Publication date: November 25, 2010
    Inventors: Takefumi Okumura, Takahiro Yamaki, Masanori Yoshikawa, Yoshimi Yanai, Toyotaka Yuasa
  • Publication number: 20100248037
    Abstract: A lithium secondary battery is intended to suppress deterioration upon storage at high temperature of 50° C. or higher without deteriorating the output characteristics at a room temperature. The battery includes a positive electrode capable of occluding and releasing lithium ions, a negative electrode capable of occluding and releasing lithium ions, a separator disposed between the positive electrode and the negative electrode, and an electrolyte. The electrolyte contains a compound having a double bond in the molecule and a compound having a plurality of polymerizable functional groups in the molecule, and the electrolyte contains a compound represented by formula (4): (in which Z1 and Z2 each represent any one of an allyl group, a methallyl group, a vinyl group, an acryl group, and a methacryl group).
    Type: Application
    Filed: January 28, 2010
    Publication date: September 30, 2010
    Applicant: Hitachi Vehicle Energy, Ltd.
    Inventors: Takefumi OKUMURA, Shigetaka Tsubouchi, Ryo Inoue
  • Patent number: 7759003
    Abstract: A polymerizable boric compound for electrochemical devices represented by the formula (1), wherein, B represents a boron atom, Z represents a polymerizable functional group, X represents a divalent C1-12 hydrocarbon group or in the absence of X, Z and B form a direct bond, AO represents a C2-4 oxyalkylene group, m and n are each the number of moles of the oxyalkylene group added and each independently stands for 2 or greater but less than 6, and R1 and R2 each represents a C1-12 hydrocarbon group.
    Type: Grant
    Filed: December 15, 2005
    Date of Patent: July 20, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Norio Iwayasu, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
  • Publication number: 20100179350
    Abstract: A polymerizable boric compound for electrochemical devices represented by the formula (1), wherein, B represents a boron atom, Z represents a polymerizable functional group, X represents a divalent C1-12 hydrocarbon group or in the absence of X, Z and B form a direct bond, AO represents a C2-4 oxyalkylene group, m and n are each the number of moles of the oxyalklylene group added and each independently stands for 2 or greater but less than 6, and R1 and R2 each represents a C1-12 hydrocarbon group.
    Type: Application
    Filed: March 22, 2010
    Publication date: July 15, 2010
    Inventors: Norio IWAYASU, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
  • Patent number: 7704642
    Abstract: The disclosure discloses a polymer represented by the general formula, wherein Rp is a residue of a polymer of a compound having a polymerizable unsaturated bond, Q is an organic residue of n+1 valences and connected directly or through another group to Rp by means of a single bond, Mk+ is a cation of k valence, Z is an organic function group capable of forming an ionic bond with cation Mk+ or an organic function group having a coordination capability with Mk+, and m, n and k are integers of one or more. The disclosure also discloses an intermediate of the polymer mentioned above.
    Type: Grant
    Filed: November 1, 2007
    Date of Patent: April 27, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Shin Nishimura, Akira Satou, Takefumi Okumura, Makoto Morishima, Hitoshi Yamamoto, Norikazu Ueyama
  • Publication number: 20090325041
    Abstract: A lithium secondary battery is disclosed which includes: a cathode that is capable of storing/releasing a lithium ion, an anode that is capable of storing/releasing a lithium ion, a separator that separates the electrodes from each other, and an electrolyte solution. The cathode includes a cathode-active material and an electroconductive material comprised of at least one gas-generating resin that is decomposed with generation of a gas at a temperature at which oxygen is eliminated from the cathode-active material, and an electroconductive filler.
    Type: Application
    Filed: June 25, 2009
    Publication date: December 31, 2009
    Applicant: Hitachi, Ltd.
    Inventors: Takefumi OKUMURA, Shigetaka Tsubouchi
  • Patent number: 7473492
    Abstract: The object of the present invention is to provide a lithium secondary battery of high output. According to the present invention, there is provided a lithium secondary battery having a positive electrode and a negative electrode which reversibly intercalate and deintercalate lithium and an electrolyte containing an ion conductive material and an electrolytic salt, where said electrolyte contains an electrolytic salt and a boron-containing compound represented by the following formula (1) or a polymer thereof, or a copolymer of the compounds of the following formulas (2) and (3).
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: January 6, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Takeshi Yabe
  • Publication number: 20080241701
    Abstract: The present invention provides a lithium secondary battery which has improved safety, mainly coming from use of an electrolyte solution which is not inflammable at room temperature (20° C.), while not deteriorating output characteristics at low temperatures and room temperature or output maintenance characteristics after storage at high temperature (50° C.). The lithium secondary battery of the present invention, encased in a container, is provided with a cathode and an anode, both capable of storing/releasing lithium ions, a separator which separates these electrodes from each other, and an electrolyte solution containing a cyclic carbonate and a linear carbonate as solvents and a compound such as VC at composition ratios of 18.0 to 30.0%, 74.0 to 81.9% and 0.1 to 1.0%, respectively, based on the whole solvents, all percentages by volume.
    Type: Application
    Filed: January 25, 2008
    Publication date: October 2, 2008
    Inventors: Takefumi Okumura, Takahiro Yamaki, Masanori Yoshikawa, Yoshimi Yanai, Toyotaka Yuasa
  • Publication number: 20080187839
    Abstract: The disclosure discloses a polymer represented by the general formula, Rp?Q?Z . . . Mk+)n]m, wherein Rp is a residue of a polymer of a compound having a polymerizable unsaturated bond, Q is an organic residue of n+1 valences and connected directly or through another group to Rp by means of a single bond, Mk+ is a cation of k valence, Z is an organic function group capable of forming an ionic bond with cation Mk+ or an organic function group having a coordination capability with Mk+, and m, n and k are integers of one or more. The disclosure also discloses an intermediate of the polymer mentioned above.
    Type: Application
    Filed: November 1, 2007
    Publication date: August 7, 2008
    Inventors: Shin NISHIMURA, Akira Satou, Takefumi Okumura, Makoto Morishima, Hitoshi Yamamoto, Norikazu Ueyama
  • Publication number: 20070287070
    Abstract: This invention provides a high-power secondary battery using a polymer electrolyte, a positive electrode, and a negative electrode. Such secondary battery comprises a positive electrode comprising a positive electrode active material that deintercalates and intercalates cations, a negative electrode comprising a negative electrode active material that intercalates and deintercalates cations deintercalated from the positive electrode, and an electrolytic layer comprising an ion conductive polymer that mediates between the positive electrode and the negative electrode and allows the cations to migrate, wherein the positive or negative electrode comprises an organic boron-containing compound as a binder component and the positive and/or negative electrode active material is treated with silane or aluminum.
    Type: Application
    Filed: July 20, 2005
    Publication date: December 13, 2007
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Tetsuya Itoh, Takeshi Yabe, Kengo Ichimiya