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).
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Patent number: 7629079Abstract: 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: GrantFiled: September 28, 2001Date of Patent: December 8, 2009Assignees: Dai-Ichi Kogyo Seiyaki Co., Ltd., Sharp CorporationInventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata, Kouichi Ui
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Patent number: 7273503Abstract: 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: GrantFiled: September 28, 2001Date of Patent: September 25, 2007Assignee: Sharp CorporationInventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
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Patent number: 7270914Abstract: 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: GrantFiled: September 28, 2001Date of Patent: September 18, 2007Assignee: Sharp CorporationInventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
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Patent number: 7238444Abstract: 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: GrantFiled: September 28, 2001Date of Patent: July 3, 2007Assignees: Dai-Ichi Kogyo Seiyaku Co., Ltd., Sharp CorporationInventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
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Patent number: 7192675Abstract: 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: GrantFiled: September 28, 2001Date of Patent: March 20, 2007Assignee: Sharp Kabushiki KaishaInventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
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Publication number: 20050100788Abstract: 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: ApplicationFiled: September 28, 2001Publication date: May 12, 2005Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
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Publication number: 20040048159Abstract: 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: ApplicationFiled: September 3, 2003Publication date: March 11, 2004Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata
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Publication number: 20040043296Abstract: A lithium secondary battery which comprises:Type: ApplicationFiled: September 15, 2003Publication date: March 4, 2004Inventors: Tsutomu Lithium, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata, Kouichi Ui
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Publication number: 20040029010Abstract: 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: ApplicationFiled: August 12, 2003Publication date: February 12, 2004Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada
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Publication number: 20040029009Abstract: 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: ApplicationFiled: August 12, 2003Publication date: February 12, 2004Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Mishimura, Takehito Mitate, Kazuo Yamada
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Publication number: 20040023114Abstract: 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: ApplicationFiled: August 20, 2003Publication date: February 5, 2004Inventors: Tsutomu Sada, Kazunari Takeda, Yumiko Takashima, Naoto Nishimura, Takehito Mitate, Kazuo Yamada, Motoaki Nishijima, Naoto Torata