Patents by Inventor Takefumi Okumura

Takefumi Okumura 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: 7300991
    Abstract: The disclosure discloses a polymer represented by the general formula, wherein Rp is a residue of a polymer of a compound having a polymerizable unsaturated bond, Q is an organic residue of n+1 valences and connected directly or through another group to Rp by means of a single bond, Mk+ is a cation of k valence, Z is an organic function group capable of forming an ionic bond with cation Mk+ or an organic function group having a coordination capability with Mk+, and m, n and k are integers of one or more. The disclosure also discloses an intermediate of the polymer mentioned above.
    Type: Grant
    Filed: March 21, 2003
    Date of Patent: November 27, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Shin Nishimura, Akira Satou, Takefumi Okumura, Makoto Morishima, Hitoshi Yamamoto, Norikazu Ueyama
  • Patent number: 7230057
    Abstract: An object of the present invention is to provide a boron-containing compound capable of forming an ion-conductive polyelectrolyte having high ion-conductive properties, and a polymer of said compound.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: June 12, 2007
    Assignees: Hitachi, Ltd., NOF Corporation
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Takeshi Yabe
  • Publication number: 20070048616
    Abstract: The present invention provides a high-power secondary battery using a gel electrolyte comprising a polymer matrix, which is obtained by polymerizing a polymerizable functional group-terminated borate represented by formula (1) or a mixture composed of a borate represented by formula (2) and a borate represented by formula (3), an electrolytic salt, and further a nonaqueous solvent: wherein Z1, Z2, and Z3 each independently represent a polymerizable functional group or a hydrocarbon group having 1 to 10 carbon atoms, provided that an average mole of the hydrocarbon group having 1 to 10 carbon atoms is 1.0 to 2.
    Type: Application
    Filed: March 16, 2006
    Publication date: March 1, 2007
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Kazushige Kohno, Shoichi Yokoyama, Masato Mizutani, Tetsuya Itoh
  • Publication number: 20070048618
    Abstract: This invention provides electrochemical devices that facilitate formation of an electric double layer, i.e., a reaction field at the electrode interface, for the purpose of reducing interface resistance. Such electrochemical devices each independently have a positive electrode and a negative electrode, wherein the positive electrode and the negative electrode are each in contact with a polymer, and wherein the Lewis acid properties of a polymer that is in contact with the positive electrode are different from those of a polymer that is in contact with the negative electrode.
    Type: Application
    Filed: August 17, 2006
    Publication date: March 1, 2007
    Inventors: Takefumi Okumura, Masanori Sakai, Akira Satou
  • Publication number: 20060147805
    Abstract: A polymerizable boric compound for electrochemical devices represented by the formula (1), wherein, B represents a boron atom, Z represents a polymerizable functional group, X represents a divalent C1-12 hydrocarbon group or in the absence of X, Z and B form a direct bond, AO represents a C2-4 oxyalkylene group, m and n are each the number of moles of the oxyalklylene group added and each independently stands for 2 or greater but less than 6, and R1 and R2 each represents a C1-12 hydrocarbon group.
    Type: Application
    Filed: December 15, 2005
    Publication date: July 6, 2006
    Inventors: Norio Iwayasu, Shin Nishimura, Takefumi Okumura, Tetsuya Itoh, Takeshi Yabe
  • Publication number: 20050260501
    Abstract: An electrolyte with excellent ionic conductivity, and a lithium secondary battery utilizing the electrolyte for increased level of safety. The lithium secondary battery comprises a positive and a negative electrode that reversibly intercalate and deintercalate lithium, and an electrolyte containing a lithium ion. The electrolyte comprises: a polymer having a carbonate group represented by formula 1 below: where R1 is a hydrocarbon group with a carbon number of 2 to 7, and n is an integer from 10 to 10000; an electrolyte salt; and an organic solvent. The electrolyte salt is contained with a molar ratio of 0.2 or more with respect to the carbonate group, thereby providing the battery with an excellent ionic conductivity and high levels of safety.
    Type: Application
    Filed: February 11, 2005
    Publication date: November 24, 2005
    Inventors: Takefumi Okumura, Shin Nishimura
  • Publication number: 20040147697
    Abstract: An object of the present invention is to provide a boron-containing compound capable of forming an ion-conductive polyelectrolyte having high ion-conductive properties, and a polymer of said compound.
    Type: Application
    Filed: November 21, 2003
    Publication date: July 29, 2004
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Takeshi Yabe
  • Publication number: 20040101759
    Abstract: The object of the present invention is to provide a lithium secondary battery of high output. According to the present invention, there is provided a lithium secondary battery having a positive electrode and a negative electrode which reversibly intercalate and deintercalate lithium and an electrolyte containing an ion conductive material and an electrolytic salt, where said electrolyte contains an electrolytic salt and a boron-containing compound represented by the following formula (1) or a polymer thereof, or a copolymer of the compounds of the following formulas (2) and (3).
    Type: Application
    Filed: November 21, 2003
    Publication date: May 27, 2004
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Takeshi Yabe
  • Publication number: 20040101758
    Abstract: The object of the present invention is to provide a lithium secondary battery of high output. According to the present invention, there is provided a lithium secondary battery having a positive electrode and a negative electrode which reversibly intercalate and deintercalate lithium and an electrolyte containing an ion conductive material and an electrolytic salt, where said electrolyte contains an electrolytic salt and a boron-containing compound represented by the following formula (1) or a polymer thereof, or a copolymer of the compounds of the following formulas (2) and (3).
    Type: Application
    Filed: July 22, 2003
    Publication date: May 27, 2004
    Inventors: Takefumi Okumura, Shin Nishimura, Norio Iwayasu, Shoichi Yokoyama, Takeshi Yabe
  • Publication number: 20030194610
    Abstract: The disclosure discloses a polymer represented by the general formula, 1
    Type: Application
    Filed: March 21, 2003
    Publication date: October 16, 2003
    Inventors: Shin Nishimura, Akira Satou, Takefumi Okumura, Makoto Morishima, Hitoshi Yamamoto, Norikazu Ueyama
  • Publication number: 20030031932
    Abstract: An electrolyte, which comprises (a) a compound having at least one methylene group adjacent to an oxygen atom in the molecule, (b) a compound represented by the following formula (1), 1
    Type: Application
    Filed: September 20, 2001
    Publication date: February 13, 2003
    Inventors: Takefumi Okumura, Shin Nishimura, Masaki Akatsuka