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).
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Publication number: 20120100436Abstract: 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: ApplicationFiled: June 21, 2010Publication date: April 26, 2012Inventors: Ryo Inoue, Shigetaka Tsubouchi, Takefumi Okumura
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Publication number: 20120081077Abstract: 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: ApplicationFiled: September 8, 2011Publication date: April 5, 2012Applicant: Hitachi, Ltd.Inventors: Hironori SASAKI, Tsunenori Yamamoto, Takefumi Okumura
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Publication number: 20110195319Abstract: 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: ApplicationFiled: February 9, 2011Publication date: August 11, 2011Inventors: Takefumi OKUMURA, Ryo INOUE
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Publication number: 20110187312Abstract: 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: ApplicationFiled: January 28, 2011Publication date: August 4, 2011Inventors: Tsunenori YAMAMOTO, Takefumi Okumura, Hironori Sasaki
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Publication number: 20110183213Abstract: 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: ApplicationFiled: January 11, 2011Publication date: July 28, 2011Inventors: Ryo INOUE, Takefumi OKUMURA
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Publication number: 20110171501Abstract: 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: ApplicationFiled: January 11, 2011Publication date: July 14, 2011Inventors: Takefumi Okumura, Ryo Inoue, Toshio Abe
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Publication number: 20110171525Abstract: 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: ApplicationFiled: January 12, 2011Publication date: July 14, 2011Inventors: Toshio ABE, Takefumi Okumura
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Publication number: 20110143196Abstract: 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: ApplicationFiled: December 7, 2010Publication date: June 16, 2011Inventors: Takefumi OKUMURA, Ryo Inoue, Toshio Haba, Chieko Araki
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Patent number: 7923580Abstract: 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: GrantFiled: March 22, 2010Date of Patent: April 12, 2011Assignee: Hitachi, Ltd.Inventors: Norio Iwayasu, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
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Patent number: 7862933Abstract: 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: GrantFiled: January 25, 2008Date of Patent: January 4, 2011Assignee: Hitachi Vehicle Energy, Ltd.Inventors: Takefumi Okumura, Takahiro Yamaki, Masanori Yoshikawa, Yoshimi Yanai, Toyotaka Yuasa
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Publication number: 20100297509Abstract: 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: ApplicationFiled: August 3, 2010Publication date: November 25, 2010Inventors: Takefumi Okumura, Takahiro Yamaki, Masanori Yoshikawa, Yoshimi Yanai, Toyotaka Yuasa
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Publication number: 20100248037Abstract: 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: ApplicationFiled: January 28, 2010Publication date: September 30, 2010Applicant: Hitachi Vehicle Energy, Ltd.Inventors: Takefumi OKUMURA, Shigetaka Tsubouchi, Ryo Inoue
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Patent number: 7759003Abstract: 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: GrantFiled: December 15, 2005Date of Patent: July 20, 2010Assignee: Hitachi, Ltd.Inventors: Norio Iwayasu, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
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Publication number: 20100179350Abstract: 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: ApplicationFiled: March 22, 2010Publication date: July 15, 2010Inventors: Norio IWAYASU, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
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Patent number: 7704642Abstract: 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: GrantFiled: November 1, 2007Date of Patent: April 27, 2010Assignee: Hitachi, Ltd.Inventors: Shin Nishimura, Akira Satou, Takefumi Okumura, Makoto Morishima, Hitoshi Yamamoto, Norikazu Ueyama
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Publication number: 20090325041Abstract: 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: ApplicationFiled: June 25, 2009Publication date: December 31, 2009Applicant: Hitachi, Ltd.Inventors: Takefumi OKUMURA, Shigetaka Tsubouchi
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Patent number: 7473492Abstract: 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: GrantFiled: November 21, 2003Date of Patent: January 6, 2009Assignee: Hitachi, Ltd.Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Takeshi Yabe
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Publication number: 20080241701Abstract: 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: ApplicationFiled: January 25, 2008Publication date: October 2, 2008Inventors: Takefumi Okumura, Takahiro Yamaki, Masanori Yoshikawa, Yoshimi Yanai, Toyotaka Yuasa
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Publication number: 20080187839Abstract: 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: ApplicationFiled: November 1, 2007Publication date: August 7, 2008Inventors: Shin NISHIMURA, Akira Satou, Takefumi Okumura, Makoto Morishima, Hitoshi Yamamoto, Norikazu Ueyama
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Publication number: 20070287070Abstract: 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: ApplicationFiled: July 20, 2005Publication date: December 13, 2007Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Tetsuya Itoh, Takeshi Yabe, Kengo Ichimiya