Patents by Inventor Ryuichi Kasahara

Ryuichi Kasahara 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: 10374219
    Abstract: The object of an exemplary embodiment of the invention is to provide a lithium ion secondary battery having an excellent charge and discharge cycle property. An exemplary embodiment of the invention is a lithium ion secondary battery, comprising a battery assembly in which a positive electrode and a negative electrode are stacked through a separator and a package in which the battery assembly and an electrolyte are placed; wherein the negative electrode comprises a negative electrode collector which is composed of a metal and a negative electrode active material layer which is formed on the negative electrode collector and which comprises a negative electrode active material and a binder; wherein the negative electrode collector and the negative electrode active material layer have a crack which is formed so as to be communicated with each of them; and wherein the crack reaches an outer peripheral edge from an inside of the negative electrode.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: August 6, 2019
    Assignee: NEC Corporation
    Inventors: Ryuichi Kasahara, Jiro Iriyama, Shin Serizawa, Hiroo Takahashi, Tatsuji Numata
  • Patent number: 9768476
    Abstract: A control system for a lithium secondary battery measures a voltage V of a negative electrode that uses silicon oxide as a negative electrode active material, with respect to a lithium reference electrode and a discharge capacity Q of the lithium secondary battery during discharge of the lithium secondary battery; generates a V?dQ/dV curve representing a relationship between dQ/dV, which is a proportion of an amount of change dQ in the discharge capacity Q to an amount of change dV in the voltage V, and the voltage V; calculates an intensity ratio of two peaks appearing on the V?dQ/dV curve for two voltage values in the voltage V; and senses a state of the negative electrode utilizing the intensity ratio.
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: September 19, 2017
    Assignees: NEC CORPORATION, NEC ENERGY DEVICES, LTD.
    Inventors: Jiro Iriyama, Tetsuya Kajita, Daisuke Kawasaki, Ryuichi Kasahara, Tatsuji Numata
  • Patent number: 9263741
    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: Grant
    Filed: December 17, 2009
    Date of Patent: February 16, 2016
    Assignee: NEC Energy Devices, Ltd.
    Inventors: Jiro Iriyama, Ryuichi Kasahara, Tetsuya Kajita, Tatsuji Numata
  • Patent number: 9160004
    Abstract: In a lithium ion secondary battery including a positive electrode, a separator, and a negative electrode opposed to the positive electrode with an intervention of the separator, the negative electrode includes a negative electrode active material including a silicon compound, and a negative electrode binder including a particular polyimide, and lithium is occluded in both the negative electrode active material and the negative electrode binder even during discharge.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: October 13, 2015
    Assignee: NEC Corporation
    Inventors: Ryuichi Kasahara, Jiro Iriyama, Kazuhiko Inoue
  • Publication number: 20150200425
    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: March 27, 2015
    Publication date: July 16, 2015
    Applicants: NEC ENERGY DEVICES, LTD., NEC CORPORATION
    Inventors: Jiro IRIYAMA, Tetsuya KAJITA, Daisuke KAWASAKI, Ryuichi KASAHARA, Tatsuji NUMATA
  • Patent number: 9076995
    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: Grant
    Filed: March 21, 2012
    Date of Patent: July 7, 2015
    Assignee: NEC CORPORATION
    Inventors: Shin Serizawa, Hiroo Takahashi, Daisuke Kawasaki, Jiro Iriyama, Ryuichi Kasahara, Emiko Fujii, Tetsuya Kajita, Tatsuji Numata
  • Patent number: 9018916
    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: Grant
    Filed: July 20, 2011
    Date of Patent: April 28, 2015
    Assignees: NEC Corporation, NEC Energy Devices, Ltd.
    Inventors: Jiro Iriyama, Tetsuya Kajita, Daisuke Kawasaki, Ryuichi Kasahara, Tatsuji Numata
  • Patent number: 8956762
    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: Grant
    Filed: July 29, 2011
    Date of Patent: February 17, 2015
    Assignees: NEC Corporation, NEC Energy Devices, Ltd.
    Inventors: Ryuichi Kasahara, Jiro Iriyama, Tetsuya Kajita, Hiroo Takahashi, Tatsuji Numata, Daisuke Kawasaki
  • Publication number: 20140356711
    Abstract: In a lithium ion secondary battery including a positive electrode, a separator, and a negative electrode opposed to the positive electrode with an intervention of the separator, the negative electrode includes a negative electrode active material including a silicon compound, and a negative electrode binder including a particular polyimide, and lithium is occluded in both the negative electrode active material and the negative electrode binder even during discharge.
    Type: Application
    Filed: September 13, 2012
    Publication date: December 4, 2014
    Inventors: Ryuichi Kasahara, Jiro Iriyama, Kazuhiko Inoue
  • Publication number: 20140127557
    Abstract: The object of an exemplary embodiment of the invention is to provide a lithium ion secondary battery having an excellent charge and discharge cycle property. An exemplary embodiment of the invention is a lithium ion secondary battery, comprising a battery assembly in which a positive electrode and a negative electrode are stacked through a separator and a package in which the battery assembly and an electrolyte are placed; wherein the negative electrode comprises a negative electrode collector which is composed of a metal and a negative electrode active material layer which is formed on the negative electrode collector and which comprises a negative electrode active material and a binder; wherein the negative electrode collector and the negative electrode active material layer have a crack which is formed so as to be communicated with each of them; and wherein the crack reaches an outer peripheral edge from an inside of the negative electrode.
    Type: Application
    Filed: April 13, 2012
    Publication date: May 8, 2014
    Inventors: Ryuichi Kasahara, Jiro Iriyama, Shin Serizawa, Hiroo Takahashi, Tatsuji Numata
  • Publication number: 20130280594
    Abstract: In a nonaqueous electrolyte secondary battery using silicon and silicon oxide as a negative electrode active material, the charge and discharge cycle characteristics are improved. A nonaqueous electrolyte secondary battery in the exemplary embodiment comprises a sheet-shaped negative electrode comprising a negative electrode active material layer comprising a composite of silicon and silicon oxide formed on a negative electrode current collector, and a sheet-shaped positive electrode comprising a positive electrode active material layer formed on a positive electrode current collector, wherein the negative electrode is disposed opposed to the positive electrode via a separator, a peripheral edge portion of the negative electrode active material layer is disposed within a peripheral edge portion of the positive electrode active material layer, and a relationship of 1.00<c is satisfied when a charge capacity of the positive electrode is a, a charge capacity of the negative electrode is b, and b/a=c is set.
    Type: Application
    Filed: January 18, 2011
    Publication date: October 24, 2013
    Applicant: NEC ENERGY DEVICES, LTD.
    Inventors: Tetsuya Kajita, Ryuichi Kasahara, Jiro Iriyama, Tatsuji Numata
  • 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: 20120276436
    Abstract: The present invention provides a stack-type lithium-ion polymer battery wherein: the battery capacity is not being degraded; the generation of the wrinkles and fracture of the separator is being suppressed; the battery has gas releasing paths; the displacement of an electrode stack hardly occurs; and the workability at the time of placing the electrode stack in a package body is improved by fixing the electrode stack. A stack-type lithium-ion polymer battery of the present invention comprises: a cathode 13; an anode 14; a separator 15; and a gel electrolyte; wherein an electrode stack 23 in which the cathode 13 and the anode 14 are stacked through the separator 15 is enclosed and fixed by insulating porous sheets 21 and 24, and is packaged with a laminate material.
    Type: Application
    Filed: July 11, 2012
    Publication date: November 1, 2012
    Applicant: NEC TOKIN CORPORATION
    Inventors: Shinako Kaneko, Ryuichi Kasahara, Hiroshi Kobayashi, Yasutaka Kono, Toshihiko Nishiyama
  • 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
  • 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