Patents by Inventor Suguru TAMAI

Suguru TAMAI 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: 11495800
    Abstract: An object of the present invention is to provide a lithium ion secondary battery having a high energy density and improved cycle characteristics. The present invention is related to an electrode for a power storage device comprising a negative electrode mixture layer comprising: (a) a negative electrode active material (42-2) comprising 1% or more of a material comprising Si as a constituent element; (b) a first polymer (42-1) coating the negative electrode active material and comprising vinylidene fluoride as a monomer unit; and (c) a negative electrode binder (42-3) comprising a second polymer that has a molecular weight of 80,000 or more and comprises at least one monomer unit selected from the group consisting of acrylic acid, acrylate salt, methacrylic acid, and methacrylate salt.
    Type: Grant
    Filed: August 14, 2018
    Date of Patent: November 8, 2022
    Assignee: NEC CORPORATION
    Inventors: Suguru Tamai, Hitoshi Ishikawa
  • Patent number: 11251424
    Abstract: A purpose of one embodiment of the present invention is to provide a lithium ion secondary battery which has improved cycle characteristics and comprises a Si material in the negative electrode. The lithium ion secondary battery according to the present invention comprises a negative electrode comprising a negative electrode active material, a positive electrode comprising a positive electrode active material and an electrolyte solution, wherein the negative electrode active material comprises a Si material, and a ratio (Ia/Ib) of a peak intensity (Ia) at 290 eV to a peak intensity (Ib) at 285 eV is 0.7 or more in a C1s spectrum obtained by surface analysis of the negative electrode by X-ray photoelectron spectroscopy.
    Type: Grant
    Filed: May 17, 2018
    Date of Patent: February 15, 2022
    Assignee: NEC CORPORATION
    Inventors: Suguru Tamai, Hitoshi Ishikawa
  • Publication number: 20210210785
    Abstract: Deterioration in cycle characteristics and battery swelling are improved. The lithium ion secondary battery of the present invention is characterized in comprising an electrolyte solution comprising a multifunctional monomer comprising two or more epoxy groups and a negative electrode comprising a binder comprising a polymer comprising a monomer unit comprising a functional group selected from the group consisting of —OH, —OM, —COOH, —COOM and —COOCnH2n+1, wherein M is a metal element, and n is an integer of 1 to 5.
    Type: Application
    Filed: October 31, 2018
    Publication date: July 8, 2021
    Applicant: NEC CORPORATION
    Inventors: Shin SERIZAWA, Suguru TAMAI, Kazuhiko INOUE
  • Publication number: 20210151749
    Abstract: A purpose of one embodiment of the present invention is to provide a lithium ion secondary battery which has improved cycle characteristics and comprises a Si material in the negative electrode. The lithium ion secondary battery according to the present invention comprises a negative electrode comprising a negative electrode active material, a positive electrode comprising a positive electrode active material and an electrolyte solution, wherein the negative electrode active material comprises a Si material, and a ratio (Ia/Ib) of a peak intensity (Ia) at 290 eV to a peak intensity (Ib) at 285 eV is 0.7 or more in a C1s spectrum obtained by surface analysis of the negative electrode by X-ray photoelectron spectroscopy.
    Type: Application
    Filed: May 17, 2018
    Publication date: May 20, 2021
    Applicant: NEC CORPORATION
    Inventors: Suguru TAMAI, Hitoshi ISHIKAWA
  • Publication number: 20200365899
    Abstract: An object of the present invention is to provide a lithium ion secondary battery having a high energy density and improved cycle characteristics. The present invention is related to an electrode for a power storage device comprising a negative electrode mixture layer comprising: (a) a negative electrode active material (42-2) comprising 1% or more of a material comprising Si as a constituent element; (b) a first polymer (42-1) coating the negative electrode active material and comprising vinylidene fluoride as a monomer unit; and (c) a negative electrode binder (42-3) comprising a second polymer that has a molecular weight of 80,000 or more and comprises at least one monomer unit selected from the group consisting of acrylic acid, acrylate salt, methacrylic acid, and methacrylate salt.
    Type: Application
    Filed: August 14, 2018
    Publication date: November 19, 2020
    Applicant: NEC CORPORATION
    Inventors: Suguru TAMAI, Hitoshi ISHIKAWA
  • Patent number: 10756337
    Abstract: When the particle size of a silicon material used for a negative electrode active material are small, a large surface area thereof easily causes a side reaction between the active material and an electrolyte solvent to occur, and the cycle characteristics of a lithium ion secondary battery decrease. In order to improve the cycle characteristics, a lithium ion secondary battery according to the present invention is characterized in comprising a negative electrode comprising a material comprising silicon as a constituent element and a polyacrylic acid, and an electrolyte solution comprising a fluoroethylene carbonate, wherein the 50% particle size of the material comprising silicon as a constituent element is 2 ?m or less.
    Type: Grant
    Filed: November 29, 2016
    Date of Patent: August 25, 2020
    Assignee: NEC CORPORATION
    Inventors: Ikiko Shimanuki, Suguru Tamai, Daisuke Kawasaki, Hitoshi Ishikawa
  • Patent number: 10707519
    Abstract: Provided is a lithium ion secondary battery that has improved cycle characteristics and employs a silicon material as a negative electrode active material. The lithium ion secondary battery according to the present invention comprises a negative electrode comprising at least a copolymer and a material comprising silicon as a constituent element, wherein the copolymer comprises a monomer unit based on an ethylenically unsaturated carboxylic acid alkali metal salt and a monomer unit based on an aromatic vinyl and the copolymer comprises an alkali metal constituting the alkali metal salt in an amount of 1000 mass ppm or more.
    Type: Grant
    Filed: November 29, 2016
    Date of Patent: July 7, 2020
    Assignee: NEC CORPORATION
    Inventor: Suguru Tamai
  • Patent number: 10644347
    Abstract: A negative electrode active material constituting a lithium ion secondary battery having high energy density and excellent cycle characteristics, and a negative electrode and a lithium ion secondary battery comprising the same are provided. The present invention relates to a negative electrode active material comprising graphite particles and crystalline silicon particles, wherein a median diameter of the crystalline silicon particles is 0.7 ?m or less, and a weight ratio of the crystalline silicon particles to the total weight of the graphite particles and the crystalline silicon particles is 1 wt % or more and 25 wt % or less.
    Type: Grant
    Filed: February 22, 2017
    Date of Patent: May 5, 2020
    Assignee: NEC Corporation
    Inventors: Daisuke Kawasaki, Takashi Ohtsuka, Suguru Tamai, Noboru Yoshida, Shinya Sudo
  • Patent number: 10637061
    Abstract: A lithium ion secondary battery excellent in cycle characteristics, comprising a high capacity negative electrode comprising a metal and/or a metal oxide as an active material is provided. The present invention relates to a lithium ion secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution, wherein the negative electrode comprises (a) a carbon material that can absorb and desorb lithium ions; at least one selected from the group consisting of (b) lithium metal and metals that can be alloyed with lithium and (c) metal oxides that can absorb and desorb lithium ions; and a polyacrylic acid, and the electrolyte solution comprises at least one disulfonic acid ester.
    Type: Grant
    Filed: May 25, 2016
    Date of Patent: April 28, 2020
    Assignee: NEC CORPORATION
    Inventors: Ikiko Shimanuki, Suguru Tamai
  • Publication number: 20190252716
    Abstract: The purpose of one embodiment of the present invention is to provide a lithium ion secondary battery which has improved cycle characteristics and the negative electrode of which comprises a silicon oxide. The present invention relates to a lithium ion secondary battery comprising a silicon oxide and an electrolyte solution comprising a fluorinated acid anhydride.
    Type: Application
    Filed: September 14, 2017
    Publication date: August 15, 2019
    Applicant: NEC Corporation
    Inventors: Suguru TAMAI, Noboru YOSHIDA
  • Publication number: 20190173123
    Abstract: A lithium ion secondary battery having high energy density and excellent cycle characteristics is provided. The present invention relates to a lithium ion secondary battery comprising a negative electrode comprising a negative electrode active material comprising more than 25% by weight of a silicon alloy and a non-aqueous electrolyte solution comprising more than 10% by weight of a compound represented by LiN(SO2CnF2n+1)2 (wherein n is an integer of 0 or more) and 10% by weight or more of fluoroethylene carbonate (FEC).
    Type: Application
    Filed: May 23, 2017
    Publication date: June 6, 2019
    Applicant: NEC CORPORATION
    Inventors: Ikiko SHIMANUKI, Daisuke KAWASAKI, Hitoshi ISHIKAWA, Suguru TAMAI
  • Publication number: 20190051928
    Abstract: A negative electrode active material constituting a lithium ion secondary battery having high energy density and excellent cycle characteristics, and a negative electrode and a lithium ion secondary battery comprising the same are provided. The present invention relates to a negative electrode active material comprising graphite particles and crystalline silicon particles, wherein a median diameter of the crystalline silicon particles is 0.7 ?m or less, and a weight ratio of the crystalline silicon particles to the total weight of the graphite particles and the crystalline silicon particles is 1 wt % or more and 25 wt % or less.
    Type: Application
    Filed: February 22, 2017
    Publication date: February 14, 2019
    Inventors: Daisuke KAWASAKI, Takashi OHTSUKA, Suguru TAMAI, Noboru YOSHIDA, Shinya SUDO
  • Publication number: 20180358610
    Abstract: When the particle size of a silicon material used for a negative electrode active material are small, a large surface area thereof easily causes a side reaction between the active material and an electrolyte solvent to occur, and the cycle characteristics of a lithium ion secondary battery decrease. In order to improve the cycle characteristics, a lithium ion secondary battery according to the present invention is characterized in comprising a negative electrode comprising a material comprising silicon as a constituent element and a polyacrylic acid, and an electrolyte solution comprising a fluoroethylene carbonate, wherein the 50% particle size of the material comprising silicon as a constituent element is 2 ?m or less.
    Type: Application
    Filed: November 29, 2016
    Publication date: December 13, 2018
    Applicant: NEC Corporation
    Inventors: Ikiko SHIMANUKI, Suguru TAMAI, Daisuke KAWASAKI, Hitoshi ISHIKAWA
  • Publication number: 20180351203
    Abstract: Provided is a lithium ion secondary battery that has improved cycle characteristics and employs a silicon material as a negative electrode active material. The lithium ion secondary battery according to the present invention comprises a negative electrode comprising at least a copolymer and a material comprising silicon as a constituent element, wherein the copolymer comprises a monomer unit based on an ethylenically unsaturated carboxylic acid alkali metal salt and a monomer unit based on an aromatic vinyl and the copolymer comprises an alkali metal constituting the alkali metal salt in an amount of 1000 mass ppm or more.
    Type: Application
    Filed: November 29, 2016
    Publication date: December 6, 2018
    Applicant: NEC Corporation
    Inventor: Suguru TAMAI
  • Publication number: 20180151882
    Abstract: A lithium ion secondary battery excellent in cycle characteristics, comprising a high capacity negative electrode comprising a metal and/or a metal oxide as an active material is provided. The present invention relates to a lithium ion secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution, wherein the negative electrode comprises (a) a carbon material that can absorb and desorb lithium ions; at least one selected from the group consisting of (b) lithium metal and metals that can be alloyed with lithium and (c) metal oxides that can absorb and desorb lithium ions; and a polyacrylic acid, and the electrolyte solution comprises at least one disulfonic acid ester.
    Type: Application
    Filed: May 25, 2016
    Publication date: May 31, 2018
    Applicant: NEC Corporation
    Inventors: Ikiko SHIMANUKI, Suguru TAMAI
  • Publication number: 20170338515
    Abstract: The present invention is a lithium-ion secondary battery including: a positive electrode containing a positive electrode active material; and an electrolyte solution containing a supporting electrolyte and a non-aqueous solvent, wherein the positive electrode active material contains a lithium-nickel composite oxide, and the electrolyte solution further contains vinylene carbonate (VC), fluoroethylene carbonate (FEC), and a boron complex of the formula (1). The content of the VC in the electrolyte solution is more than 0 mass % and 2.5 mass % or less, the content of the FEC in the electrolyte solution is more than 0 mass % and 2.0 mass % or less, the content of the boron complex of the formula (1) in the electrolyte solution is more than 0 mass % and 1.0 mass % or less, and the total content of the VC, the FEC, and the boron complex of the formula (1) in the electrolyte solution is less than 4.5 mass %. (Z, A1, A2, B1, B2, and Q1 in the formula (1) are as defined in the description.
    Type: Application
    Filed: October 9, 2015
    Publication date: November 23, 2017
    Applicant: NEC ENERGY DEVICES, LTD.
    Inventors: Shinako KANEKO, Suguru TAMAI