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).

  • Patent number: 7687202
    Abstract: A non-aqueous electrolyte secondary battery including: a positive electrode having a positive electrode material mixture containing a composite lithium oxide; a negative electrode; a polyolefin separator; a non-aqueous electrolyte; and a heat-resistant insulating layer interposed between the positive and negative electrodes. The positive electrode active material mixture has an estimated heat generation rate at 200° C. of not greater than 50 W/kg. The estimated heat generation rate is determined by obtaining a relation between absolute temperature T and heat generation rate V of the positive electrode material mixture using an accelerating rate calorimeter; plotting a relation between the inverse of absolute temperature T and the logarithm of heat generation rate V according to the Arrhenius law; obtaining a straight line fitted to the plotted points in a heat generation temperature range of T<200° C.; and extrapolating the straight line to the temperature of 200° C.
    Type: Grant
    Filed: December 23, 2005
    Date of Patent: March 30, 2010
    Assignee: Panasonic Corporation
    Inventors: Hajime Nishino, Shinji Kasamatsu, Hideharu Takezawa, Kazuhiro Okamura, Mikinari Shimada
  • Publication number: 20090155686
    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: Application
    Filed: December 11, 2006
    Publication date: June 18, 2009
    Inventor: Hideharu Takezawa
  • Publication number: 20090117463
    Abstract: In a lithium ion secondary battery including a positive electrode, a negative electrode containing an alloy-based negative electrode active material, a separator, a positive electrode lead, a negative electrode lead, a gasket, and an outer case, the positive electrode is allowed to contain an oxygen deficient non-stoichiometric oxide, or an oxygen removing layer containing an oxygen deficient non-stoichiometric oxide is provided between the positive electrode and the separator. In a lithium ion secondary battery containing the alloy-based negative electrode active material, a reaction between oxygen generated in the positive electrode and the alloy-based negative electrode active material, and heat generation accompanying the reaction are prevented.
    Type: Application
    Filed: October 30, 2008
    Publication date: May 7, 2009
    Inventors: Hideharu Takezawa, Masato Fujikawa, Miyuki Nakai
  • Publication number: 20090104515
    Abstract: A lithium secondary battery of this invention includes: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; a separator; and a non-aqueous electrolyte. The negative electrode active material includes a first portion capable of absorbing and desorbing lithium ions and a second portion covering at least a part of a surface of the first portion. The second portion includes at least one material that is less reactive with oxygen than the first portion.
    Type: Application
    Filed: October 22, 2008
    Publication date: April 23, 2009
    Inventors: Masato Fujikawa, Hideharu Takezawa, Miyuki Nakai
  • Publication number: 20090104529
    Abstract: An object of the present invention is to provide an electrode for a lithium ion secondary battery that can ensure a high level of safety even when exposed to severe conditions such as a nail penetration test or crush test, and exhibit excellent output characteristics. The present invention relates to an electrode for a lithium ion secondary battery having a material mixture containing active material particles capable of reversibly absorbing and desorbing lithium, and a current collector that carries the material mixture, wherein a surface of the current collector has recessed portions, and an area occupied by the recessed portions accounts for not less than 30% of an a material mixture carrying area of the current collector.
    Type: Application
    Filed: July 21, 2006
    Publication date: April 23, 2009
    Inventors: Hajime Nishino, Shuji Tsutsumi, Shinji Kasamatsu, Hideharu Takezawa, Mikinari Shimada
  • Publication number: 20090098451
    Abstract: In a lithium ion secondary battery including a flat-plate electrode assembly which is configured by stacking the positive electrode, the separator, and the negative electrode in the thickness direction thereof, each of the positive electrode and the negative electrode includes a current collector and an active material layer. Each of the current collector includes a substantially rectangular current collector body, a heat radiating portion, and a lead portion, and the heat radiating portions are projected toward the outside of the electrode assembly so as not to overlap with each other in the thickness direction of the electrode assembly. In this way, heat caused inside the lithium ion secondary battery can be diffused efficiently to the outside, and safety of the lithium ion secondary battery can be further increased, without complicating the battery structure and decreasing mechanical strength of the battery.
    Type: Application
    Filed: October 8, 2008
    Publication date: April 16, 2009
    Inventors: Tomohiko Yokoyama, Masato Fujikawa, Hideharu Takezawa, Shinji Kasamatsu
  • Publication number: 20090098459
    Abstract: A method for manufacturing an electrode of an electrochemical element includes: (A) forming an active material layer on a current collector; and (B) providing lithium to the active material layer. The A step and the B step are carried out in continuous space.
    Type: Application
    Filed: December 27, 2007
    Publication date: April 16, 2009
    Inventors: Hideharu Takezawa, Toshitada Sato, Kazuyoshi Honda
  • Publication number: 20090042097
    Abstract: A lithium ion secondary battery includes a negative electrode that is shaped like waves in a section in the thickness direction. In the negative electrode, the ratio t1/t0 of the largest thickness t1 to the smallest thickness t0 is from 1.2 to 3.0. The negative electrode includes a thin-film negative electrode active material layer in which the ratio A/B of the volume A in a charged state to the volume B in a discharged state is 1.2 or more. The lithium ion secondary battery has high capacity, high power, long life, and improved safety. In particular, heat generation due to an internal short-circuit is significantly suppressed in a nail penetration test.
    Type: Application
    Filed: August 7, 2008
    Publication date: February 12, 2009
    Inventors: Masato Fujikawa, Hideharu Takezawa, Shinji Kasamatsu, Tomohiko Yokoyama
  • Publication number: 20090017375
    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: Application
    Filed: January 26, 2007
    Publication date: January 15, 2009
    Inventor: Hideharu Takezawa
  • Publication number: 20080254353
    Abstract: According to a method for manufacturing an electrode of an electrochemical device, an electrode precursor capable of absorbing and releasing lithium is provided with lithium, and the resistance of the electrode precursor is measured after absorbing lithium. In addition, a processing apparatus for an electrode of an electrochemical device includes a lithium providing section for providing lithium to such an electrode precursor, and a first measurement section for measuring the resistance of the electrode precursor after absorbing lithium.
    Type: Application
    Filed: April 10, 2008
    Publication date: October 16, 2008
    Inventor: Hideharu TAKEZAWA
  • Publication number: 20080248189
    Abstract: The invention presents a manufacturing method of an electrode for an electrochemical element for inserting and extracting a lithium ion reversibly, comprising; forming a concave portion and a convex portion at least on one side of a current collector, preparing a raw material containing a element for composing an active material, introducing a specified supply amount of the raw material and a carrier gas into a film forming device to form a plasma, and injecting the plasma of the raw material on the current collector, in which the active material is grown on the convex portion of the current collector, and a columnar body is formed by covering at least a part of respective sides of the convex portion.
    Type: Application
    Filed: April 2, 2008
    Publication date: October 9, 2008
    Inventors: Takashi Ohtsuka, Kaoru Nagata, Hideharu Takezawa, Shoichi Imashiku
  • Publication number: 20080248388
    Abstract: The invention presents an electrode for an electrochemical element for inserting and extracting a lithium ion reversibly, comprising a current collector forming a concave portion and a convex portion at least on one side, and a columnar body including an active material formed on the convex portion of the current collector, in which the columnar body covers at least a part of respective sides of the convex portion. By this configuration, an electrode for an electrochemical element of long life and excellent reliability is realized.
    Type: Application
    Filed: April 4, 2008
    Publication date: October 9, 2008
    Inventors: Takashi Ohtsuka, Kaoru Nagata, Hideharu Takezawa, Shoichi Imashiku
  • Patent number: 7425386
    Abstract: An electrode group for a battery including a positive electrode and a negative electrode wound into a spiral with a separator interposed therebetween, wherein the positive electrode includes a positive electrode current collector and positive electrode material mixture layers formed on both sides of the positive electrode current collector, the negative electrode includes a negative electrode current collector and negative electrode material mixture layers formed on both sides of the negative electrode current collector, a lead is connected to at least one of the positive electrode current collector and the negative electrode current collector, and at least one of step portions having difference in level formed in the electrode group by lengthwise ends of the positive electrode, the negative electrode and the separator and the periphery of the lead, respectively, is covered with an insulating member arranged on an inner circumference side or an outer circumference side of a turn of the electrode group.
    Type: Grant
    Filed: September 22, 2003
    Date of Patent: September 16, 2008
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideharu Takezawa, Shuji Tsutsumi, Mikinari Shimada
  • Publication number: 20080199775
    Abstract: In a method for examining a negative electrode of a battery, a total thickness of a current collector and an active material layer is measured. Then, in order to estimate a composition of the active material layer, the total resistivity of the current collector and the active material layer is measured.
    Type: Application
    Filed: February 1, 2008
    Publication date: August 21, 2008
    Inventors: Hideharu TAKEZAWA, Takayuki Shirane, Shinya Fujimura, Sadayuki Okazaki, Kazuyoshi Honda
  • Publication number: 20080187835
    Abstract: A method for examining a negative electrode of a non-aqueous electrolyte secondary battery includes irradiating an active material layer including silicon or a silicon compound having a known composition, which is capable of electrochemically absorbing and releasing lithium ions on a current collector made of a metal including at least any one of copper, nickel, titanium and iron, with an X-ray; and measuring an attenuation amount of any one of a CuK? ray, a NiK? ray, a TiK? ray, and a FeK? ray, which is a fluorescent X-ray of the metal included in the current collector in fluorescent X-rays generated from the active material layer.
    Type: Application
    Filed: February 1, 2008
    Publication date: August 7, 2008
    Inventors: Hideharu TAKEZAWA, Takayuki Shirane, Shinya Fujimura, Sadayuki Okazaki, Kazuyoshi Honda
  • Publication number: 20080187832
    Abstract: In a method for manufacturing a negative electrode for a battery, an active material layer including a metallic element M and an element A that is at least any one of oxygen, nitrogen, and carbon is formed on a current collector. This active material layer is irradiated with an X-ray and at least one of intensity of a K? ray of the element A and intensity of a K? ray of the metallic element M in fluorescent X-rays generated from the active material layer is measured.
    Type: Application
    Filed: February 1, 2008
    Publication date: August 7, 2008
    Inventors: Hideharu TAKEZAWA, Takayuki SHIRANE, Shinya FUJIMURA, Sadayuki OKAZAKI, Kazuyoshi HONDA
  • Publication number: 20080187833
    Abstract: In a method for testing a negative electrode of a secondary battery, light is irradiate to an active material layer formed on a current collector having a plurality of projections at least on one side thereof, the active material layer including first columnar bodies of active material grown obliquely from the projections. The angle is measured between the reflected light from the active material layer and a normal line parallel to the thickness direction of the current collector.
    Type: Application
    Filed: February 1, 2008
    Publication date: August 7, 2008
    Inventors: Hideharu TAKEZAWA, Shinya FUJIMURA, Sadayuki OKAZAKI, Kazuyoshi HONDA
  • Publication number: 20080187834
    Abstract: A method for manufacturing a negative electrode of a battery includes forming an active material layer and a active material layer for measuring both including a material having a characteristic absorption in an infrared region on a surface of a sent current collector and a surface of a measuring current collector that is being sent faster than the current collector, respectively; and irradiating the active material layer for measuring with an infrared ray and measuring a wave number of a reflected infrared ray in order to estimate a composition of at least the active material layer for measuring.
    Type: Application
    Filed: February 1, 2008
    Publication date: August 7, 2008
    Inventors: Hideharu TAKEZAWA, Takayuki Shirane, Shinya Fujimura, Sadayuki Okazaki, Kazuyoshi Honda
  • Publication number: 20080160412
    Abstract: In the non-aqueous electrolyte secondary battery of the present invention, the separator includes a heat-resistant resin having chlorine atoms as an end group and the positive electrode active material includes a lithium-containing complex oxide containing aluminum atoms in its composition. Even if the chlorine atoms are liberated into the non-aqueous electrolyte, aluminum contained in the positive electrode active material is selectively leached into the non-aqueous electrolyte, thereby suppressing the leaching of other component elements. Consequently, there can be obtained a non-aqueous electrolyte secondary battery excellent in safety and high temperature storage characteristics.
    Type: Application
    Filed: March 9, 2006
    Publication date: July 3, 2008
    Inventors: Shinji Kasamatsu, Hajime Nishino, Hideharu Takezawa
  • Publication number: 20080118842
    Abstract: A method of manufacturing a negative electrode for a non-aqueous electrolyte secondary battery includes a step of imparting lithium to a precursor of the negative electrode capable of storing and releasing lithium, by a film forming method in a dry process. In this step, the precursor is brought into contact with a measuring terminal having a non-aqueous electrolyte and a counter electrode. The amount of lithium stored in the precursor is calculated from an open circuit potential of the precursor with respect to the counter electrode. Further, according to the calculated amount of stored lithium, the amount of lithium to be imparted to the precursor is controlled.
    Type: Application
    Filed: October 30, 2007
    Publication date: May 22, 2008
    Inventor: Hideharu Takezawa