Patents by Inventor Tatsuji Numata

Tatsuji Numata 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: 20130244086
    Abstract: Provided are a negative electrode for a secondary battery realizing satisfactory cycle characteristics and a method for manufacturing the same, and a nonaqueous electrolyte secondary battery having satisfactory cycle characteristics. A negative electrode for a secondary battery formed by bonding a negative electrode active material to a negative electrode collector with a negative electrode binder, in which the negative electrode binder is a polyimide or a polyamide-imide, and the negative electrode collector is a Cu alloy containing at least one metal (a) selected from the group consisting of Sn, In, Mg and Ag and has a conductivity of 50 IACS % or more.
    Type: Application
    Filed: August 25, 2011
    Publication date: September 19, 2013
    Applicant: NEC ENERGY DEVICES, LTD.
    Inventors: Jiro Iriyama, Daisuke Kawasaki, Ryuichi Kasahara, Tetsuya Kajita, Tatsuji Numata
  • Publication number: 20130119940
    Abstract: There is provided a control system for a lithium secondary battery that can quantitatively sense a deterioration state inherent in a lithium secondary battery using silicon oxide as a negative electrode active material, that is, the nonuniform reaction state of a negative electrode.
    Type: Application
    Filed: July 20, 2011
    Publication date: May 16, 2013
    Applicants: NEC ENERGY DEVICES, LTD., NEC CORPORATION
    Inventors: Jiro Iriyama, Tetsuya Kajita, Daisuke Kawasaki, Ryuichi Kasahara, Tatsuji Numata
  • Patent number: 8435672
    Abstract: The invention provides a lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolysis solution containing an aprotic solvent having an electrolyte dissolved in it, wherein the negative electrodes uses an amorphous carbon material as a negative electrode active material. The amorphous carbon material has (A) an average particle diameter (median size) of 7 ?m to 20 ?m inclusive as measured by a laser diffraction scattering method and (B) a particle size distribution as measured by a laser diffraction scattering method, in which distribution the ratio of particles of less than 3 ?m in diameter is 1% by mass to 10% mass inclusive, and is free of an electrical conducting material.
    Type: Grant
    Filed: April 19, 2007
    Date of Patent: May 7, 2013
    Assignee: NEC Energy Devices, Ltd.
    Inventors: Yutaka Bannai, Tatsuji Numata, Ryuichi Kasahara
  • Publication number: 20130108914
    Abstract: In a lithium ion secondary battery including a positive electrode, a separator, a negative electrode, and a package body, the negative electrode includes simple substance silicon as a negative electrode active material, and a negative electrode binder, and is doped with lithium, and the following formulas (1) and (2) are satisfied: 1.2?Ma/Mc?1.9??(1) 1.0<Ma/(Mc+MLi)<1.6??(2) wherein an amount of lithium inserted into the negative electrode until the negative electrode reaches a potential of 0.02 V with respect to metal lithium is Ma (a number of atoms), an amount of lithium released from the positive electrode until the positive electrode reaches a potential of 4.3 V with respect to metal lithium is Mc (a number of atoms), and an amount of lithium with which the negative electrode is doped is MLi (a number of atoms).
    Type: Application
    Filed: July 29, 2011
    Publication date: May 2, 2013
    Applicants: NEC ENERGY DEVICES, LTD., NEC CORPORATION
    Inventors: Ryuichi Kasahara, Jiro Iriyama, Tetsuya Kajita, Hiroo Takahashi, Tatsuji Numata, Daisuke Kawasaki
  • Publication number: 20130101899
    Abstract: There is provided a nonaqueous electrolyte secondary battery having high capacity in which the reduction in the capacity of the battery due to the irreversible capacity in the first charge and discharge is suppressed using a high capacity positive electrode.
    Type: Application
    Filed: June 6, 2011
    Publication date: April 25, 2013
    Applicant: NEC ENERGY DEVICES, LTD.
    Inventors: Tetsuya Kajita, Hiroo Takahashi, Ryuichi Kasahara, Jiro Iriyama, Tatsuji Numata
  • Publication number: 20120321962
    Abstract: There is provided a polymer secondary battery using silicon and silicon oxide as a negative electrode active material that shows a high capacity retention rate also when a charge and discharge cycle is repeated. A polymer secondary battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a polymer-containing gel electrolyte, wherein the negative electrode includes silicon and silicon oxide as a negative electrode active material, and the polymer-containing gel electrolyte is present in voids formed by fine division of particles of the negative electrode active material.
    Type: Application
    Filed: February 18, 2011
    Publication date: December 20, 2012
    Applicant: NEC ENERGY DEVICES, LTD.
    Inventors: Tetsuya Kajita, Yasutaka Kono, Ryuichi Kasahara, Jiro Iriyama, Tatsuji Numata
  • Publication number: 20120244420
    Abstract: A secondary battery according to the present exemplary embodiment is a secondary battery including a laminated electrode body provided with at least one pair of positive and negative electrodes and an outer enclosure that accommodates the laminated electrode body, wherein the outer enclosure includes one or more concave portions, inside a border corresponding to an outer edge of an electrode surface of an outermost layer of the laminated electrode body, on a surface facing the electrode surface, and wherein, when a band-shaped outer circumferential region having an area that is a half of an area inside the border is set inside the border, at least one of the concave portions is located inside the outer circumferential region.
    Type: Application
    Filed: March 21, 2012
    Publication date: September 27, 2012
    Applicant: NEC CORPORATION
    Inventors: Shin SERIZAWA, Hiroo TAKAHASHI, Daisuke KAWASAKI, Jiro IRIYAMA, Ryuichi KASAHARA, Emiko FUJII, Tetsuya KAJITA, Tatsuji NUMATA
  • Patent number: 8227116
    Abstract: A lithium secondary battery which has excellent characteristics such as energy density and electromotive force and is excellent in cycle life and storage stability is provided. The secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution comprising an aprotic solvent having at least an electrolyte dissolved therein, wherein the positive electrode comprises a lithium-manganese composite oxide having a spinel structure as a positive electrode active material, and the electrolyte solution comprises a compound represented by the general formula (1).
    Type: Grant
    Filed: December 14, 2004
    Date of Patent: July 24, 2012
    Assignee: NEC Corporation
    Inventors: Daisuke Kawasaki, Yuki Kusachi, Tatsuji Numata, Koji Utsugi
  • Publication number: 20110318637
    Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0?a1?1, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2<0.3, and the z2 satisfies 0<z2<2.
    Type: Application
    Filed: September 2, 2011
    Publication date: December 29, 2011
    Applicant: NEC TOKIN CORPORATION
    Inventors: Takehiro Noguchi, Masaaki Matsuu, Ryuichi Kasahara, Tatsuji Numata, Yutaka Bannai
  • Publication number: 20110274966
    Abstract: An exemplary embodiment of the invention provides a nonaqueous electrolytic solution secondary battery in which capacity deterioration associated with a charge/discharge cycle at a high temperature (45° C. or higher) can be prevented. An exemplary embodiment of the invention is a nonaqueous electrolytic solution secondary battery, comprising an electrode element in which a cathode and an anode are stacked, a nonaqueous electrolytic solution which contains at least one of carbonate solvent, and a gel in an outer packaging body; wherein the anode comprises a silicon oxide represented by SiOx (0<x?2) as an anode active material, and the gel comprises a cross-linked unsaturated carboxylate ester polymer and a carbonate solvent which is the same as at least one of the carbonate solvent contained in the nonaqueous electrolytic solution.
    Type: Application
    Filed: January 19, 2010
    Publication date: November 10, 2011
    Inventors: Jiro Iriyama, Tatsuji Numata, Ryuichi Kasahara, Tetsuya Kajita
  • Publication number: 20110244328
    Abstract: There is provided a negative electrode for a nonaqueous electrolyte secondary battery in which when a battery is formed, the energy density is high, and moreover, the decrease in charge and discharge capacity is small even if charge and discharge are repeated. By using silicon oxide particles having a particle diameter in a particular range as a starting raw material, and heating these particles in the range of 850° C. to 1050° C., Si microcrystals are deposited on the surfaces of the particles. Then, by performing doping of Li, a structure comprising a plurality of protrusions having height and cross-sectional area in a particular range is formed on the surfaces. The average value of the height of the above protrusions is 2% to 19% of the average particle diameter of the above lithium-containing silicon oxide particles.
    Type: Application
    Filed: December 17, 2009
    Publication date: October 6, 2011
    Applicant: NEC ENERGY DEVICES, LTD.
    Inventors: Jiro Iriyama, Ryuichi Kasahara, Tetsuya Kajita, Tatsuji Numata
  • Publication number: 20100173201
    Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0?a1?1, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2<0.3, and the z2 satisfies 0<z2<2.
    Type: Application
    Filed: March 17, 2010
    Publication date: July 8, 2010
    Applicant: NEC TOKIN CORPORATION
    Inventors: Takehiro NOGUCHI, Masaaki MATSUU, Ryuichi KASAHARA, Tatsuji NUMATA, Yutaka BANNAI
  • Publication number: 20100173200
    Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0?a1?1, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2?0.3, and the z2 satisfies 0?z2?2.
    Type: Application
    Filed: March 17, 2010
    Publication date: July 8, 2010
    Applicant: NEC TOKIN CORPORATION
    Inventors: Takehiro NOGUCHI, Masaaki MATSUU, Ryuichi KASAHARA, Tatsuji NUMATA, Yutaka BANNAI
  • Patent number: 7556889
    Abstract: A life of a secondary battery is extended, increase in a resistance when storing a secondary battery at an elevated temperature is prevented, and increase in a resistance during a charge-discharge cycle is prevented. A positive electrode active material comprising a lithium manganate and a lithium nickelate are used. The lithium manganate is a compound represented by the following formula (1) or the compound in which some of Mn or O sites are replaced with another element: Li1+xMn2?xO4??(1) (in the above-shown formula (1), 0.15?x?0.24).
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: July 7, 2009
    Assignee: NEC Corporation
    Inventors: Tomokazu Kumeuchi, Tatsuji Numata, Daisuke Kawasaki
  • Patent number: 7335444
    Abstract: A positive electrode active material containing lithium manganate having a spinel structure is used, wherein the value of a* of the L*a*b* color specification system is made to satisfy the requirement: ?3.2 ?a*??1.4. Or, the value of a* is made to satisfy the requirement: ?5.8 23 a*??4.2. Or, the value of L* is made to satisfy the requirement: 24 ?L*?27.
    Type: Grant
    Filed: September 28, 2005
    Date of Patent: February 26, 2008
    Assignee: NEC Corporation
    Inventors: Tatsuji Numata, Yoshitada Tomioka
  • Publication number: 20070248885
    Abstract: The invention provides a lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolysis solution containing an aprotic solvent having an electrolyte dissolved in it, wherein the negative electrodes uses an amorphous carbon material as a negative electrode active material. The amorphous carbon material has (A) an average particle diameter (median size of 7 ?m to 20 ?m inclusive as measured by a laser diffraction scattering method and (B) a particle size distribution as measured by a laser diffraction scattering method, in which distribution the ratio of particles of less than 3 ?m in diameter is 1% by mass to 10% mass inclusive, and is free of an electrical conducting material.
    Type: Application
    Filed: April 19, 2007
    Publication date: October 25, 2007
    Applicant: NEC TOKIN Corporation
    Inventors: Yutaka Bannai, Tatsuji Numata, Ryuichi Kasahara
  • Publication number: 20070172734
    Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0<a1<, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2<0.3, and the z2 satisfies 0<z2<2.
    Type: Application
    Filed: January 24, 2007
    Publication date: July 26, 2007
    Inventors: Takehiro NOGUCHI, Masaaki MATSUU, Ryuichi KASAHARA, Tatsuji NUMATA, Yutaka BANNAI
  • Publication number: 20070154815
    Abstract: A lithium secondary battery which has excellent characteristics such as energy density and electromotive force and is excellent in cycle life and storage stability is provided. The secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution comprising an aprotic solvent having at least an electrolyte dissolved therein, wherein the positive electrode comprises a lithium-manganese composite oxide having a spinel structure as a positive electrode active material, and the electrolyte solution comprises a compound represented by the general formula (1).
    Type: Application
    Filed: December 14, 2004
    Publication date: July 5, 2007
    Applicant: NEC CORPORATION
    Inventors: Daisuke Kawasaki, Yuki Kusachi, Tatsuji Numata, Koji Utsugi
  • Patent number: 7179566
    Abstract: A cathode active material for a secondary battery including a lithium-manganese composite oxide having a spinel structure and represented by the following general formula (I), Lia(MxMn2-x-y-zYyAz)(O4-wZw) (I), wherein 0.5?x?1.2, 0?y, 0?z, x+y+z<2, 0?a?1.2 and 0?w?1; M contains at least Co and may further contains at least one element selected from the group consisting of Ni, Fe, Cr and Cu; Y is at least one element selected lo from the group consisting of Li, Be, B, Na, Mg, Al, K and Ca; A is at least one of Ti and Si; and Z is at least one of F and Cl. When the cathode active material for the secondary battery is used as the cathode for the a secondary battery, a higher operating can be realized while suppressing the reliability reduction such as the capacity decrease after the cycles and the deterioration of the crystalline structure at a higher temperature.
    Type: Grant
    Filed: March 7, 2003
    Date of Patent: February 20, 2007
    Assignee: NEC Corporation
    Inventors: Daisuke Kawasaki, Takehiro Noguchi, Tatsuji Numata
  • Patent number: 7026070
    Abstract: A positive electrode active material for a secondary battery contains a spinel lithium manganese composite oxide expressed by a general formula of Lia(MxMn2?x?yAy)O4 where x and y are positive values which satisfy 0.4<x, 0<y, x+y<2, and 0<a<1.2. “M” denotes Ni and at least one metal element selected from the group consisting of Co, Fe, Cr and Cu. “A” denotes at least one metal element selected from the group consisting of Si and Ti. The ratio y of A has a value of 0.1<y in case where A includes only Ti. Accordingly, it is possible to acquire a material for the positive electrode of a lithium ion secondary battery, which has a high capacity and a high energy density with a high voltage of 4.5 V or higher with respect to Li.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: April 11, 2006
    Assignee: NEC Corporation
    Inventors: Takehiro Noguchi, Tatsuji Numata