Patents by Inventor Keitaro Otsuki

Keitaro Otsuki 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: 9263736
    Abstract: A positive electrode material for a lithium ion secondary battery contains a first compound represented by Li3V2(PO4)3 and one or more second compounds selected from vanadium oxide and lithium vanadium phosphate.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: February 16, 2016
    Assignee: TDK CORPORATION
    Inventors: Keitaro Otsuki, Atsushi Sano, Tomohiko Kato
  • Publication number: 20150333366
    Abstract: A provided lithium ion secondary battery includes a pair of electrodes and a solid electrolyte layer. The solid electrolyte layer is provided between the pair of electrodes and includes titanium aluminum lithium phosphate. At least one of the pair of electrodes includes vanadium lithium phosphate. At least one of the pair of electrodes includes at least one constituent of titanium and aluminum. The amount of the at least one constituent existing on a side opposite to the solid electrolyte layer is smaller than the amount of the at least one constituent existing on the solid electrolyte layer side.
    Type: Application
    Filed: May 8, 2015
    Publication date: November 19, 2015
    Inventors: Hiroshi SATO, Tetsuya UENO, Ayaka HORIKAWA, Keitaro OTSUKI
  • Publication number: 20150333330
    Abstract: A lithium ion secondary battery including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer is provided. The positive electrode layer includes a positive electrode current collector layer and a positive electrode active material layer. Positive electrode active material layer includes a positive electrode active material. The negative electrode layer includes a negative electrode current collector layer and a negative electrode active material layer. The negative electrode active material layer includes a negative electrode active material. Solid electrolyte layer between the positive and negative electrode active material layers includes a solid electrolyte. At least one of a ratio of a particle diameter of the solid electrolyte to a particle diameter of the positive electrode active material and a ratio of the particle diameter of the solid electrolyte to a particle diameter of the negative electrode active material is in the range of 1/10 to 1/3.
    Type: Application
    Filed: May 8, 2015
    Publication date: November 19, 2015
    Inventors: Hiroshi SATO, Tetsuya UENO, Ayaka HORIKAWA, Keitaro OTSUKI
  • Publication number: 20150333362
    Abstract: A lithium ion secondary battery including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer is provided. The positive electrode layer includes a positive electrode current collector layer and a positive electrode active material layer. The positive electrode active material layer includes a positive electrode active material. The negative electrode layer includes a negative electrode current collector layer and a negative electrode active material layer. The negative electrode active material layer includes a negative electrode active material. The solid electrolyte layer between the positive and negative electrode active material layers includes a solid electrolyte. At least one of a ratio of a particle diameter of the solid electrolyte to a particle diameter of the positive electrode active material and a ratio of the particle diameter of the solid electrolyte to a particle diameter of the negative electrode active material ranges from 3.0 to 10.0.
    Type: Application
    Filed: May 8, 2015
    Publication date: November 19, 2015
    Inventors: Hiroshi SATO, Tetsuya UENO, Ayaka HORIKAWA, Keitaro OTSUKI
  • Publication number: 20150255795
    Abstract: The present invention aims to obtain a lithium ion secondary battery having excellent high-rate discharge characteristics. A lithium ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution and is characterized in that the positive electrode uses a compound expressed by an expression as a positive electrode active material, and the positive electrode has an electrode density of 1.8 to 2.9 g/cm3, the expression being Lia(M)b(PO4)cXd (where M is VO or V, X is F, and 0.9?a?3.3, 0.9?b?2.2, 0.9?c?3.3, 0?d?1.1).
    Type: Application
    Filed: September 27, 2013
    Publication date: September 10, 2015
    Inventors: Atsushi Sano, Keitaro Otsuki
  • Patent number: 8993171
    Abstract: To provide an active material from which a sufficient discharge capacity is obtained, an electrode containing the active material, a lithium secondary battery including the electrode, and a method for making an active material. A method for making an active material includes a temperature elevation step of heating a mixture containing a lithium source, a pentavalent vanadium source, a phosphoric acid source, water, and a reductant in a hermetically sealed container at a temperature elevation rate T1 from 25° C. to 110° C. and then at a temperature elevation rate T2 from 110° C. to a designated temperature of 200° C. or more, in which T1>T2; T1=0.5 to 10° C./min; and T2=0.1 to 2.2° C./min.
    Type: Grant
    Filed: July 12, 2011
    Date of Patent: March 31, 2015
    Assignee: TDK Corporation
    Inventors: Atsushi Sano, Keitaro Otsuki, Kouji Tokita, Tomohiko Kato, Akiji Higuchi
  • Patent number: 8936871
    Abstract: An active material contains a triclinic LiVOPO4 crystal particle, while the crystal particle has a spherical form and an average particle size of 20 to 200 nm.
    Type: Grant
    Filed: September 28, 2009
    Date of Patent: January 20, 2015
    Assignee: TDK Corporation
    Inventors: Atsushi Sano, Keitaro Otsuki, Yosuke Miyaki, Takeshi Takahashi, Akiji Higuchi
  • Patent number: 8932762
    Abstract: A method for manufacturing an active material containing a triclinic LiVOPO4 crystal particle that has a spherical form and an average particle size of 20 to 200 nm. The method includes a step of manufacturing the crystal particle by hydrothermal synthesis.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: January 13, 2015
    Assignee: TDK Corporation
    Inventors: Atsushi Sano, Keitaro Otsuki, Yosuke Miyaki, Takeshi Takahashi, Akiji Higuchi
  • Patent number: 8906255
    Abstract: The lithium-ion secondary battery in which a positive electrode contains Lia(M)b(PO4)cFd (M=VO or V, 0.9?a?3.3, 0.9?b?2.2, 0.9?c?3.3, 0?d?2.0) as an active material and 1 to 300 ppm of sulfur is used.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: December 9, 2014
    Assignee: TDK Corporation
    Inventors: Atsushi Sano, Keitaro Otsuki
  • Patent number: 8821763
    Abstract: An active material capable of forming an electrochemical device excellent in its discharge capacity and rate characteristic is provided. The active material in accordance with a first aspect of the present invention comprises a compound particle containing a compound having a composition represented by the following chemical formula (1), a carbon layer covering the compound particle, and a carbon particle. The active material in accordance with a second aspect of the present invention comprises a carbon particle and a compound particle having an average primary particle size of 0.03 to 1.4 ?m, being carried by the carbon particle, and containing a compound represented by the following chemical formula (1): LiaMXO4??(1) where a satisfies 0.9?a?2, M denotes one species selected from the group consisting of Fe, Mn, Co, Ni, and VO, and X denotes one species selected from the group consisting of P, Si, S, V, and Ti.
    Type: Grant
    Filed: September 28, 2009
    Date of Patent: September 2, 2014
    Assignee: TDK Corporation
    Inventors: Atsushi Sano, Keitaro Otsuki, Yosuke Miyaki, Takeshi Takahashi, Tohru Inoue, Akiji Higuchi
  • Patent number: 8734539
    Abstract: The first aspect of the present invention provides a method of manufacturing an active material capable of improving the discharge capacity of a lithium-ion secondary battery. The method of manufacturing an active material in accordance with the first aspect of the present invention comprises the steps of heating a phosphate source, a vanadium source, and water so as to form an intermediate containing phosphorus and vanadium and having a specific surface area of at least 0.1 m2/g but less than 25 m2/g; and heating the intermediate, a water-soluble lithium salt, and water. The second aspect of the present invention provides a method of manufacturing an active material capable of improving the rate characteristic of a lithium-ion secondary battery.
    Type: Grant
    Filed: September 22, 2010
    Date of Patent: May 27, 2014
    Assignee: TDK Corporation
    Inventors: Kouji Tokita, Keitaro Otsuki, Atsushi Sano
  • Patent number: 8734987
    Abstract: The method of manufacturing an active material in accordance with the first aspect of the invention yields an active material containing LiVOPO4 capable of improving the cycle characteristic of a battery. Methods of manufacturing active materials in accordance with the second, third, and fourth aspects of the present invention yield active materials containing LiVOPO4 capable of improving the discharge capacity of a battery.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: May 27, 2014
    Assignee: TDK Corporation
    Inventors: Atsushi Sano, Keitaro Otsuki, Kouji Tokita, Tomohiko Kato, Akiji Higuchi
  • Publication number: 20140004416
    Abstract: A method for manufacturing an active material, capable of improving the discharge capacity of a lithium ion secondary battery is provided. The method for manufacturing an active material according to the present invention includes a first step of heating a mixture solution including a lithium source, a phosphate source, a vanadium source, and water under pressure to generate a precursor in the mixture solution, and adjusting the pH of the mixture solution including the precursor to be 6 to 8; and a second step of heating the precursor at 425 to 650° C. after the first step to generate an active material.
    Type: Application
    Filed: March 30, 2012
    Publication date: January 2, 2014
    Applicant: TDK CORPORATION
    Inventors: Atsushi Sano, Keitaro Otsuki, Tomohiko Kato, Akinobu Nojima, Akiji Higuchi
  • Publication number: 20140004417
    Abstract: An active material capable of improving the discharge capacity of a lithium ion secondary battery is provided. The active material of the present invention includes LiVOPO4 and one or more metal elements selected from the group consisting of Al, Nb, Ag, Mg, Mn, Fe, Zr, Na, K, B, Cr, Co, Ni, Cu, Zn, Si, Be, Ti, and Mo.
    Type: Application
    Filed: March 30, 2012
    Publication date: January 2, 2014
    Applicant: TDK CORPORATION
    Inventors: Atsushi Sano, Keitaro Otsuki, Tomohiko Kato, Akiji Higuchi
  • Publication number: 20140001413
    Abstract: An active material that can achieve sufficient discharge capacity at high discharging rate, an electrode including the active material, and a lithium ion secondary battery including the electrode, and a method for manufacturing the active material are provided. The active material includes a LiVOPO4 powder, a first carbon powder, and a second carbon powder. A relational expression of 0.05?A1/A2?0.5 is satisfied, where A1 represents the ratio of the G band peak height observed around 1580 cm?1 in Raman spectrum of the first carbon powder to the 2D band peak height observed around 2700 cm?1 in the Raman spectrum of the first carbon powder, and A2 represents the ratio of the G band peak height observed around 1580 cm?1 in Raman spectrum of the second carbon powder to the 2D band peak height observed around 2700 cm?1 in the Raman spectrum of the second carbon powder.
    Type: Application
    Filed: March 30, 2012
    Publication date: January 2, 2014
    Applicant: TDK CORPORATION
    Inventors: Keitaro Otsuki, Atsushi Sano
  • Publication number: 20130330261
    Abstract: A method for manufacturing an active material containing a triclinic LiVOPO4 crystal particle that has a spherical form and an average particle size of 20 to 200 nm. The method includes a step of manufacturing the crystal particle by hydrothermal synthesis.
    Type: Application
    Filed: August 16, 2013
    Publication date: December 12, 2013
    Applicant: TDK CORPORATION
    Inventors: Atsushi SANO, Keitaro OTSUKI, Yosuke MIYAKI, Takeshi TAKAHASHI, Akiji HIGUCHI
  • Publication number: 20130260226
    Abstract: A nonaqueous electrolyte for a lithium-ion secondary battery containing 0.1 ppm to 20 ppm of vanadium in terms of vanadium ions, and containing cyclic carbonate and chain carbonate is used.
    Type: Application
    Filed: March 18, 2013
    Publication date: October 3, 2013
    Applicant: TDK CORPORATION
    Inventors: Atsushi SANO, Keitaro OTSUKI, Keiichi FUKUDA
  • Publication number: 20130260253
    Abstract: A positive electrode material for a lithium ion secondary battery contains a first compound represented by Li3V2(PO4)3 and one or more second compounds selected from vanadium oxide and lithium vanadium phosphate.
    Type: Application
    Filed: March 18, 2013
    Publication date: October 3, 2013
    Inventors: Keitaro OTSUKI, Atsushi SANO, Tomohiko KATO
  • Publication number: 20130256592
    Abstract: The lithium-ion secondary battery in which a positive electrode contains Lia(M)b(PO4)cFd (M=VO or V, 0.9?a?3.3, 0.9?b?2.2, 0.9?c?3.3, 0?d?2.0) as an active material and 1 to 300 ppm of sulfur is used.
    Type: Application
    Filed: March 18, 2013
    Publication date: October 3, 2013
    Applicant: TDK CORPORATION
    Inventors: Atsushi SANO, Keitaro OTSUKI
  • Publication number: 20130260228
    Abstract: The lithium-ion secondary battery includes a positive electrode containing an active material made of a compound including lithium and a transition metal; an electrolyte containing 5 to 30 ppm of hydrofluoric acid; and a negative electrode containing 1 to 100 ppm of vanadium.
    Type: Application
    Filed: March 18, 2013
    Publication date: October 3, 2013
    Applicant: TDK CORPORATION
    Inventors: Atsushi SANO, Keitaro OTSUKI, Masahiro OISHI, Keiichi FUKUDA