Patents by Inventor Yumiko Takashima

Yumiko Takashima 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: 7629079
    Abstract: A lithium secondary battery which comprises: a negative electrode comprising as an active material a carbonaceous material capable of electrochemically holding/releasing lithium; a positive electrode comprising as an active material a lithium chalcogenide; and polymer electrolyte layers united respectively with the negative electrode and the positive electrode. The polymer electrolyte layers comprise an ionically conductive polymer matrix holding a nonaqueous electrolytic solution. They are obtained by crosslinking and polymerizing a liquid mixture of a monomeric precursor for the ionically conductive polymer and the nonaqueous electrolytic solution respectively on the negative electrode and the positive electrode using different polymerization initiators.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: December 8, 2009
    Assignees: Dai-Ichi Kogyo Seiyaki Co., Ltd., Sharp Corporation
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata, Kouichi Ui
  • Patent number: 7273503
    Abstract: A lithium polymer secondary cell having a negative electrode, a positive electrode and, arranged between the electrodes, a polymer electrolyte layer, characterized in that the cell has been subjected to a heat treatment at a temperature of 40 to 60° C. after the assembly thereof. The polymer cell is freed of or is reduced in the adverse effect of a residual monomer and initiator on the performance of the cell. The polymer electrolyte is formed by cross-linking polymerization of a precursor monomer for an ion conducting polymer in a non-aqueous electrolyte, and the residual monomer and initiator contained therein is consumed by the heat treatment.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: September 25, 2007
    Assignee: Sharp Corporation
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
  • Patent number: 7270914
    Abstract: In a lithium secondary cell having a negative electrode, a positive electrode and, arranged between the electrodes, a polymer electrolyte layer, the internal resistance of the cell and the interfacial resistance between the electrode and the polymer electrolyte can be reduced by incorporating into the electrode, in advance, a polymer electrolyte precursor solution in a manner such that the electrode has a higher content of the precursor monomer and/or an oligomer thereof than that in the polymer electrolyte layer formed on the electrode.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: September 18, 2007
    Assignee: Sharp Corporation
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
  • Patent number: 7238444
    Abstract: A lithium secondary battery which comprises a negative electrode, a positive electrode, and disposed therebetween a polymer electrolyte comprising an ionically conductive polymer. The polymer electrolyte has a two-layer structure composed of a positive-electrode-side layer and a negative-electrode-side layer. The polymer electrolyte on the positive-electrode side contains a nonaqueous electrolytic solution containing a lithium salt in a higher concentration than that in the polymer electrolyte on the negative-electrode side. The battery is improved in charge/discharge cycling characteristics and high-load discharge characteristics.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: July 3, 2007
    Assignees: Dai-Ichi Kogyo Seiyaku Co., Ltd., Sharp Corporation
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
  • Patent number: 7192675
    Abstract: A lithium polymer secondary battery which comprises a negative electrode, a positive electrode, and polymer electrolyte layers united respectively with the two electrodes and differing in viscoelastic behavior. In this battery, conformation to the expansion and shrinkage accompanying charge/discharge is easy and the interfacial resistance between each electrode and the polymer electrolyte is kept low.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: March 20, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
  • Publication number: 20050100788
    Abstract: In a lithium secondary cell having a negative electrode, a positive electrode and, arranged between the electrodes, a polymer electrolyte layer, the internal resistance of the cell and the interfacial resistance between the electrode and the polymer electrolyte can be reduced by incorporating into the electrode, in advance, a polymer electrolyte precursor solution in a manner such that the electrode has a higher content of the precursor monomer and/or an oligomer thereof than that in the polymer electrolyte layer formed on the electrode.
    Type: Application
    Filed: September 28, 2001
    Publication date: May 12, 2005
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
  • Publication number: 20040048159
    Abstract: A lithium polymer secondary battery which comprises a negative electrode, a positive electrode, and polymer electrolyte layers united respectively with the two electrodes and differing in viscoelastic behavior. In this battery, conformation to the expansion and shrinkage accompanying charge/discharge is easy and the interfacial resistance between each electrode and the polymer electrolyte is kept low.
    Type: Application
    Filed: September 3, 2003
    Publication date: March 11, 2004
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
  • Publication number: 20040043296
    Abstract: A lithium secondary battery which comprises:
    Type: Application
    Filed: September 15, 2003
    Publication date: March 4, 2004
    Inventors: Tsutomu Lithium, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata, Kouichi Ui
  • Publication number: 20040029010
    Abstract: A lithium secondary battery which comprises a negative electrode, a positive electrode, and disposed therebetween a polymer electrolyte comprising an ionically conductive polymer. The polymer electrolyte has a two-layer structure composed of a positive-electrode-side layer and a negative-electrode-side layer. The polymer electrolyte on the positive-electrode side contains a nonaqueous electrolytic solution containing a lithium salt in a higher concentration than that in the polymer electrolyte on the negative-electrode side. The battery is improved in charge/discharge cycling characteristics and high-load discharge characteristics.
    Type: Application
    Filed: August 12, 2003
    Publication date: February 12, 2004
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada
  • Publication number: 20040029009
    Abstract: A lithium secondary cell with a small decrease in discharge capacity during high-load discharge and little self-discharge. The electrolytic layers of the cell consist of positive-side and negative-side polymer electrolytic layers integrated with their respective electrodes, wherein the positive-side electrolytic layer is lower than the negative-side electrolytic layer indirect current resistance.
    Type: Application
    Filed: August 12, 2003
    Publication date: February 12, 2004
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Mishimura, Takehito Mitate, Kazuo Yamada
  • Publication number: 20040023114
    Abstract: A lithium polymer secondary cell having a negative electrode, a positive electrode and, arranged between the electrodes, a polymer electrolyte layer, characterized in that the cell has been subjected to a heat treatment at a temperature of 40 to 60° C. after the assembly thereof. The polymer cell is freed of or is reduced in the adverse effect of a residual monomer and initiator on the performance of the cell. The polymer electrolyte is formed by cross-linking polymerization of a precursor monomer for an ion conducting polymer in a non-aqueous electrolyte, and the residual monomer and initiator contained therein is consumed by the heat treatment.
    Type: Application
    Filed: August 20, 2003
    Publication date: February 5, 2004
    Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata