Patents by Inventor Hideharu Takezawa

Hideharu Takezawa 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: 20110279088
    Abstract: A battery pack includes at least a lithium ion secondary battery, a voltage sensor, and a control unit. The control unit controls discharge of the battery by a relatively high end-of-discharge voltage when the use frequency of the battery is relatively low during discharge of the battery. On the other hand, the control unit controls discharge of the battery by a relatively low end-of-discharge voltage when the use frequency of the battery is relatively high. Consequently, it is possible to prevent the utilizable capacity from decreasing more than a practical decrease in the capacity due to increase in the use frequency.
    Type: Application
    Filed: December 1, 2010
    Publication date: November 17, 2011
    Inventors: Taisuke Yamamoto, Masaya Ugaji, Hideharu Takezawa, Tatsuki Hiraoka
  • Patent number: 8039148
    Abstract: A non-aqueous electrolyte secondary battery of this invention includes a positive electrode including a positive electrode mixture, a negative electrode including a negative electrode mixture, and a non-aqueous electrolyte. The negative electrode mixture includes a material capable of absorbing and desorbing Li and a carbon material. The material capable of absorbing and desorbing Li includes at least one element selected from the group consisting of Si and Sn, and the amount of the carbon material is 3 to 60% by weight of the negative electrode mixture. At least one of the positive electrode, the negative electrode, and the non-aqueous electrolyte contains a lithium perfluoroalkylsulfonyl imide represented by the following general formula (1): LiN(CmF2m+1SO2)(CnF2n+1SO2)??(1) where m and n each represent an integer of 1 to 5 and may be m=n. The ratio of the weight of the lithium perfluoroalkylsulfonyl imide to the weight of the carbon material is 10?3 to 10.
    Type: Grant
    Filed: December 11, 2006
    Date of Patent: October 18, 2011
    Assignee: Panasonic Corporation
    Inventor: Hideharu Takezawa
  • Patent number: 8017262
    Abstract: A lithium secondary battery including: an electrode group, a non-aqueous electrolyte and a battery case housing the electrode group and the non-aqueous electrolyte, the electrode group including a positive electrode, a negative electrode and a separator layer interposed between the positive electrode and the negative electrode, wherein an end-of-charge voltage and an end-of-discharge voltage are set in such a manner that the electrode group has an energy density of not less than 700 Wh/L, the separator layer includes a porous heat-resistant layer, and a short circuit area A produced when an internal short circuit has occurred between the positive electrode and the negative electrode, and a reduced area B of the porous heat-resistant layer that is produced by heat generation satisfy 1?(A+B)/A?10.
    Type: Grant
    Filed: January 26, 2006
    Date of Patent: September 13, 2011
    Assignee: Panasonic Corporation
    Inventors: Masato Fujikawa, Shinji Kasamatsu, Hajime Nishino, Hideharu Takezawa, Mikinari Shimada
  • Publication number: 20110159341
    Abstract: A battery pack 1 of the present invention includes: a secondary battery 2; a molded body 11 configured to store therein the secondary battery; a temperature increase suppressing layer 13 provided between the secondary battery and an inner surface of the molded body to suppress a temperature increase of an outer surface of the molded body; and a block layer 12 provided between the secondary battery and the temperature increase suppressing layer to block leakage from the secondary battery. With this, if a malfunction, such as a case where contents, such as a molten material, flows out from the secondary battery, occurs, the contents are prevented from flowing out to the outside of the battery pack, and the temperature increase of the surface of the battery pack is suppressed.
    Type: Application
    Filed: August 31, 2009
    Publication date: June 30, 2011
    Inventors: Kazuya Iwamoto, Taisuke Yamamoto, Hideharu Takezawa, Tomohiko Yokoyama
  • Publication number: 20110143195
    Abstract: A negative electrode 10 for a lithium ion battery of the present invention includes a negative electrode current collector 11, protrusions 13 formed so as to be spaced apart from each other on a surface of the negative electrode current collector 11, columns 12 supported on the protrusions 13 one by one, and a coating layer 15 coating a surface of each of the columns 12. The columns 12 include a negative electrode active material including either one of silicon and tin, and further include lithium absorbed thereinto. The coating layer 15 contains at least one of lithium carbonate and lithium fluoride and is formed by exposing the columns 12 to an atmosphere with a dew point temperature of ?60° C. or higher and 0° C. or lower.
    Type: Application
    Filed: June 17, 2010
    Publication date: June 16, 2011
    Inventors: Shuji Ito, Tatsuki Hiraoka, katsumi Kashiwagi, Hideharu Takezawa, Masaya Ugaji, Kunihiko Mineya
  • Patent number: 7914930
    Abstract: A non-aqueous electrolyte secondary battery having both high capacity and long-life is provided by solving the problem of the large irreversible capacity of a negative electrode active material. The non-aqueous electrolyte secondary battery is produced by a method including the steps of: reacting lithium with a negative electrode active material by bringing a metal film that is composed mainly of lithium into contact with a surface of a negative electrode active material layer; and thereafter combining the negative electrode with a positive electrode to form an electrode assembly. The metal film composed mainly of lithium is preferably formed on a carrier that does not chemically react with lithium, and the metal film on the carrier is preferably brought into contact with the negative electrode active material layer while heating and applying a pressure thereto.
    Type: Grant
    Filed: November 16, 2006
    Date of Patent: March 29, 2011
    Assignee: Panasonic Corporation
    Inventors: Toshitada Sato, Hideharu Takezawa, Syoichi Imashiku, Kazuyoshi Honda
  • Publication number: 20110064983
    Abstract: Provided is a highly safe portable electronic device having a secondary battery as a power source, and including a housing, an electronic device body housed in the housing, and a battery housing portion housed in the housing, in which a surface is inhibited from being locally heated to high temperature. In the portable electronic device, the battery housing portion is a molding with a battery fitting portion for fitting the secondary battery therein, and the battery fitting portion has provided on its surface a heat-insulating layer having a thickness of from 500 to 3000 ?m and a thermal conductivity of 0.2 W/m·K or lower.
    Type: Application
    Filed: September 18, 2009
    Publication date: March 17, 2011
    Inventors: Tomohiko Yokoyama, Hideharu Takezawa, Kazuya Iwamoto, Taisuke Yamamoto
  • Publication number: 20110026207
    Abstract: A portable electronic device of the present invention includes a package, an electronic device body, a battery housing portion including a battery fitting portion for fitting a secondary battery therein, a foaming agent-containing layer provided on a surface of the battery housing portion, and a secondary battery to be fitted in the battery fitting portion. The foaming agent-containing layer is normally thin and, in the event of the battery generating heat, the layer turns into a thicker foamed layer which exhibits superior thermal insulation properties. Thus, it is possible to provide a portable electronic device having the degree of freedom in design for size and thickness reduction achieved at a high level, while offering high-level safety and reliability.
    Type: Application
    Filed: September 18, 2009
    Publication date: February 3, 2011
    Inventors: Hideharu Takezawa, Tomohiko Yokoyama, Kazuya Iwamoto, Taisuke Yamamoto
  • Publication number: 20110020536
    Abstract: A production method of an electrode for a lithium-ion secondary battery includes: (A) a step of providing a current collector 11 having a plurality of bumps 12 on a surface thereof; (B) a step of allowing an evaporated source material to strike from a direction E which is tilted with respect to the normal of the surface of the current collector 11 to form a corresponding plurality of pillar-like members 14 on the plurality of bumps 12; and (C) a step of oxidizing the plurality of pillar-like members 14 to form a plurality of active material members 18 containing an oxide of the source material.
    Type: Application
    Filed: March 26, 2009
    Publication date: January 27, 2011
    Inventors: Taisuke Yamamoto, Kazuyoshi Honda, Hideharu Takezawa
  • Publication number: 20110020688
    Abstract: Provided is a highly safe portable electronic device having a secondary battery as a power source, and including a package, an electronic device body housed in the package, and a battery housing portion housed in the package, in which even if the content melts due to an extremely significant impact applied thereto, discharge of a melt is inhibited. In the portable electronic device, the battery housing portion is a molding with a battery fitting portion for fitting the secondary battery therein, and the battery fitting portion has a covering layer, which includes a temperature suppression layer and a block layer, provided on its surface.
    Type: Application
    Filed: September 18, 2009
    Publication date: January 27, 2011
    Inventors: Hideharu Takezawa, Tomohiko Yokoyama, Kazuya Iwamoto, Taisuke Yamamoto
  • Publication number: 20110003208
    Abstract: A negative electrode for a non-aqueous electrolyte secondary battery including: a current collector; and an active material layer including at least two alloy-based active materials selected from the group consisting of silicon, tin, a silicon oxide, and a tin oxide. The active material layer includes a first portion supported on a surface of the current collector, a second portion supported on a surface of the first portion, and a third portion supported on a surface of the second portion. The first portion includes the silicon oxide or the tin oxide, and the oxygen content in the silicon oxide or the tin oxide in the first portion decreases continuously or stepwise as approaching the second portion. The second portion includes silicon or tin. The third portion includes the silicon oxide or the tin oxide, and the oxygen content in the silicon oxide or the tin oxide in the third portion increases continuously or stepwise with distance from the second portion.
    Type: Application
    Filed: July 2, 2010
    Publication date: January 6, 2011
    Inventors: Tatsuki HIRAOKA, Masaya Ugaji, Taisuke Yamamoto, Hideharu Takezawa
  • Publication number: 20100320080
    Abstract: An electrode for an electrochemical element reversibly absorbing and releasing lithium ions including: a current collector having a higher first convex portion and a lower second convex portion on at least one surface thereof; a columnar body including an active material formed in such a manner as to rise obliquely on the first convex portion and the second convex portion of the current collector.
    Type: Application
    Filed: May 15, 2008
    Publication date: December 23, 2010
    Applicant: Panasonic Corporation
    Inventors: Hideharu Takezawa, Shoichi Imashiku, Kaoru Nagata, Takashi Otsuka
  • Publication number: 20100247990
    Abstract: A battery pack 1 of the present invention includes: a plurality of lithium ion secondary batteries 10 electrically connected together in series, in parallel, or in series-parallel combination; a tray 11; and a housing 12. The lithium ion secondary batteries 10 each include an electrode assembly containing an alloy-based negative electrode active material serving as a negative electrode active material, and each have a sealed surface 10a. The lithium ion secondary battery 10 is mounted on the tray. The housing 12 accommodates the tray 11 with the lithium ion secondary battery 10 mounted thereon. Even if high-temperature contents are produced in the interior of the lithium ion secondary battery 10 in the event of internal short circuiting or overcharging, this configuration prevents the high-temperature contents from leaking out of the batter pack 1, and thus improves the safety of the battery pack 1.
    Type: Application
    Filed: June 2, 2009
    Publication date: September 30, 2010
    Inventors: Masaya Ugaji, Hideharu Takezawa, Taisuke Yamamoto, Yasushi Hirakawa
  • Patent number: 7803485
    Abstract: A positive electrode for use in a lithium secondary battery comprises a positive electrode current collector, and a positive electrode film which is carried on the positive electrode current collector and includes a plurality of mixture layers. The positive electrode film contains, as a positive electrode active material, two or more kinds of lithium-containing compounds having exothermic initiation temperatures different from each other. At least one kind of the two or more kinds of lithium-containing compounds has the exothermic initiation temperature of 300 ° C. or higher. A first mixture layer of the plural mixture layers closest to the positive electrode current collector contains at least one kind of the lithium-containing compound having the exothermic initiation temperature of 300 ° C. or higher.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: September 28, 2010
    Assignee: Panasonic Corporation
    Inventors: Hideharu Takezawa, Hajime Nishino
  • Patent number: 7754390
    Abstract: A negative electrode for a nonaqueous electrolytic rechargeable battery capable of storing and discharging lithium ions is manufactured in the steps of forming a lithium metal layer on a carrier substrate by a gas phase method, superimposing the surface of the lithium metal layer formed on the carrier substrate on a negative electrode active material layer formed on a collecting body, storing the lithium metal layer into the negative electrode active material layer in nonaqueous electrolyte, and removing the carrier substrate from the negative electrode active material layer.
    Type: Grant
    Filed: February 21, 2007
    Date of Patent: July 13, 2010
    Assignee: Panasonic Corporation
    Inventors: Hideharu Takezawa, Toshitada Sato
  • Patent number: 7736808
    Abstract: A non-aqueous electrolyte secondary battery of the present invention includes a positive electrode including a positive electrode material mixture, a negative electrode including a negative electrode material mixture, and a non-aqueous electrolyte including a non-aqueous solvent and a first lithium salt and a second lithium salt dissolved in the non-aqueous solvent. The negative electrode material mixture includes a material capable of absorbing and desorbing lithium ions, and carbon nanofibers. The material capable of absorbing and desorbing lithium ions has a ratio A/B of a volume A in a charged state to a volume B in a discharged state of 1.2 or more. The first lithium salt is at least one selected from the group consisting of LiBF4 and LiB(C2O4)2. The second lithium salt is a salt other than the first lithium salt. The first lithium salt is included in the non-aqueous electrolyte at a weight ratio of 10?4 or more relative to the carbon nanofibers.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: June 15, 2010
    Assignee: Panasonic Corporation
    Inventor: Hideharu Takezawa
  • Publication number: 20100136428
    Abstract: The non-aqueous electrolyte secondary battery of the present invention is provided with an electrode plate group and a non-aqueous electrolyte, the electrode plate group including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, a positive electrode lead connected to the positive electrode, and a negative electrode lead connected to the negative electrode. The energy density of the electrode plate group is 750 Wh/L or higher by volume, and the cross-sectional area of at least one of the positive electrode lead and the negative electrode lead is 5.5×10?5 to 1.2×10?2 cm2.
    Type: Application
    Filed: November 19, 2008
    Publication date: June 3, 2010
    Applicant: PANASONIC CORPORATION
    Inventors: Tomohiko Yokoyama, Hideharu Takezawa, Masato Fujikawa, Shinji Kasamatsu
  • Publication number: 20100136393
    Abstract: In a lithium ion secondary battery, a lithium-nickel-containing composite oxide that contains lithium and nickel is used as a positive electrode active material, and a negative electrode active material having a melting temperature of 1200° C. or less in a lithium-absorbed state is included in a negative electrode active material layer. By configuring as above, in the lithium ion secondary battery, it is possible to achieve higher capacity, higher output, and longer life, as well as further improved safety, and particularly in a nail penetration test, to suppress the heat generation due to internal short circuit and to reliably prevent the occurrence of thermal runaway.
    Type: Application
    Filed: July 17, 2008
    Publication date: June 3, 2010
    Inventors: Hideharu Takezawa, Masato Fujikawa, Miyiki Nakai, Shinji Kasamatsu, Tomohiko Yokoyama
  • Publication number: 20100112442
    Abstract: An electrode for an electrochemical device according to the present invention includes a current collector and an active material layer formed on the current collector. The active material layer includes an active material capable of reversibly absorbing and desorbing lithium ions and having a theoretical capacity density of more than 833 mAh/cm3, and the BET specific surface area of the active material layer is 5 m2/g or more and 80 m2/g or less.
    Type: Application
    Filed: October 24, 2008
    Publication date: May 6, 2010
    Inventors: Masato Fujikawa, Hideharu Takezawa, Miyuki Nakai
  • Publication number: 20100112451
    Abstract: A negative electrode 100 for a nonaqueous electrolytic secondary cell includes a current collector 1 and a plurality of active material bodies 2 formed on a surface of the current collector 1 at intervals; each active material body 2 contains a material for occluding or releasing lithium; and a plurality of projections 3 are formed on a part of a side surface of each active material body 2.
    Type: Application
    Filed: October 9, 2007
    Publication date: May 6, 2010
    Inventors: Satoshi Shibutani, Hideharu Takezawa, Kazuyoshi Honda, Toshitada Sato