Patents by Inventor Tatsuji Numata
Tatsuji Numata 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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Publication number: 20130244086Abstract: Provided are a negative electrode for a secondary battery realizing satisfactory cycle characteristics and a method for manufacturing the same, and a nonaqueous electrolyte secondary battery having satisfactory cycle characteristics. A negative electrode for a secondary battery formed by bonding a negative electrode active material to a negative electrode collector with a negative electrode binder, in which the negative electrode binder is a polyimide or a polyamide-imide, and the negative electrode collector is a Cu alloy containing at least one metal (a) selected from the group consisting of Sn, In, Mg and Ag and has a conductivity of 50 IACS % or more.Type: ApplicationFiled: August 25, 2011Publication date: September 19, 2013Applicant: NEC ENERGY DEVICES, LTD.Inventors: Jiro Iriyama, Daisuke Kawasaki, Ryuichi Kasahara, Tetsuya Kajita, Tatsuji Numata
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Publication number: 20130119940Abstract: There is provided a control system for a lithium secondary battery that can quantitatively sense a deterioration state inherent in a lithium secondary battery using silicon oxide as a negative electrode active material, that is, the nonuniform reaction state of a negative electrode.Type: ApplicationFiled: July 20, 2011Publication date: May 16, 2013Applicants: NEC ENERGY DEVICES, LTD., NEC CORPORATIONInventors: Jiro Iriyama, Tetsuya Kajita, Daisuke Kawasaki, Ryuichi Kasahara, Tatsuji Numata
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Patent number: 8435672Abstract: The invention provides a lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolysis solution containing an aprotic solvent having an electrolyte dissolved in it, wherein the negative electrodes uses an amorphous carbon material as a negative electrode active material. The amorphous carbon material has (A) an average particle diameter (median size) of 7 ?m to 20 ?m inclusive as measured by a laser diffraction scattering method and (B) a particle size distribution as measured by a laser diffraction scattering method, in which distribution the ratio of particles of less than 3 ?m in diameter is 1% by mass to 10% mass inclusive, and is free of an electrical conducting material.Type: GrantFiled: April 19, 2007Date of Patent: May 7, 2013Assignee: NEC Energy Devices, Ltd.Inventors: Yutaka Bannai, Tatsuji Numata, Ryuichi Kasahara
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Publication number: 20130108914Abstract: In a lithium ion secondary battery including a positive electrode, a separator, a negative electrode, and a package body, the negative electrode includes simple substance silicon as a negative electrode active material, and a negative electrode binder, and is doped with lithium, and the following formulas (1) and (2) are satisfied: 1.2?Ma/Mc?1.9??(1) 1.0<Ma/(Mc+MLi)<1.6??(2) wherein an amount of lithium inserted into the negative electrode until the negative electrode reaches a potential of 0.02 V with respect to metal lithium is Ma (a number of atoms), an amount of lithium released from the positive electrode until the positive electrode reaches a potential of 4.3 V with respect to metal lithium is Mc (a number of atoms), and an amount of lithium with which the negative electrode is doped is MLi (a number of atoms).Type: ApplicationFiled: July 29, 2011Publication date: May 2, 2013Applicants: NEC ENERGY DEVICES, LTD., NEC CORPORATIONInventors: Ryuichi Kasahara, Jiro Iriyama, Tetsuya Kajita, Hiroo Takahashi, Tatsuji Numata, Daisuke Kawasaki
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Publication number: 20130101899Abstract: There is provided a nonaqueous electrolyte secondary battery having high capacity in which the reduction in the capacity of the battery due to the irreversible capacity in the first charge and discharge is suppressed using a high capacity positive electrode.Type: ApplicationFiled: June 6, 2011Publication date: April 25, 2013Applicant: NEC ENERGY DEVICES, LTD.Inventors: Tetsuya Kajita, Hiroo Takahashi, Ryuichi Kasahara, Jiro Iriyama, Tatsuji Numata
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Publication number: 20120321962Abstract: There is provided a polymer secondary battery using silicon and silicon oxide as a negative electrode active material that shows a high capacity retention rate also when a charge and discharge cycle is repeated. A polymer secondary battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a polymer-containing gel electrolyte, wherein the negative electrode includes silicon and silicon oxide as a negative electrode active material, and the polymer-containing gel electrolyte is present in voids formed by fine division of particles of the negative electrode active material.Type: ApplicationFiled: February 18, 2011Publication date: December 20, 2012Applicant: NEC ENERGY DEVICES, LTD.Inventors: Tetsuya Kajita, Yasutaka Kono, Ryuichi Kasahara, Jiro Iriyama, Tatsuji Numata
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Publication number: 20120244420Abstract: A secondary battery according to the present exemplary embodiment is a secondary battery including a laminated electrode body provided with at least one pair of positive and negative electrodes and an outer enclosure that accommodates the laminated electrode body, wherein the outer enclosure includes one or more concave portions, inside a border corresponding to an outer edge of an electrode surface of an outermost layer of the laminated electrode body, on a surface facing the electrode surface, and wherein, when a band-shaped outer circumferential region having an area that is a half of an area inside the border is set inside the border, at least one of the concave portions is located inside the outer circumferential region.Type: ApplicationFiled: March 21, 2012Publication date: September 27, 2012Applicant: NEC CORPORATIONInventors: Shin SERIZAWA, Hiroo TAKAHASHI, Daisuke KAWASAKI, Jiro IRIYAMA, Ryuichi KASAHARA, Emiko FUJII, Tetsuya KAJITA, Tatsuji NUMATA
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Patent number: 8227116Abstract: A lithium secondary battery which has excellent characteristics such as energy density and electromotive force and is excellent in cycle life and storage stability is provided. The secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution comprising an aprotic solvent having at least an electrolyte dissolved therein, wherein the positive electrode comprises a lithium-manganese composite oxide having a spinel structure as a positive electrode active material, and the electrolyte solution comprises a compound represented by the general formula (1).Type: GrantFiled: December 14, 2004Date of Patent: July 24, 2012Assignee: NEC CorporationInventors: Daisuke Kawasaki, Yuki Kusachi, Tatsuji Numata, Koji Utsugi
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Publication number: 20110318637Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0?a1?1, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2<0.3, and the z2 satisfies 0<z2<2.Type: ApplicationFiled: September 2, 2011Publication date: December 29, 2011Applicant: NEC TOKIN CORPORATIONInventors: Takehiro Noguchi, Masaaki Matsuu, Ryuichi Kasahara, Tatsuji Numata, Yutaka Bannai
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Publication number: 20110274966Abstract: An exemplary embodiment of the invention provides a nonaqueous electrolytic solution secondary battery in which capacity deterioration associated with a charge/discharge cycle at a high temperature (45° C. or higher) can be prevented. An exemplary embodiment of the invention is a nonaqueous electrolytic solution secondary battery, comprising an electrode element in which a cathode and an anode are stacked, a nonaqueous electrolytic solution which contains at least one of carbonate solvent, and a gel in an outer packaging body; wherein the anode comprises a silicon oxide represented by SiOx (0<x?2) as an anode active material, and the gel comprises a cross-linked unsaturated carboxylate ester polymer and a carbonate solvent which is the same as at least one of the carbonate solvent contained in the nonaqueous electrolytic solution.Type: ApplicationFiled: January 19, 2010Publication date: November 10, 2011Inventors: Jiro Iriyama, Tatsuji Numata, Ryuichi Kasahara, Tetsuya Kajita
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Publication number: 20110244328Abstract: There is provided a negative electrode for a nonaqueous electrolyte secondary battery in which when a battery is formed, the energy density is high, and moreover, the decrease in charge and discharge capacity is small even if charge and discharge are repeated. By using silicon oxide particles having a particle diameter in a particular range as a starting raw material, and heating these particles in the range of 850° C. to 1050° C., Si microcrystals are deposited on the surfaces of the particles. Then, by performing doping of Li, a structure comprising a plurality of protrusions having height and cross-sectional area in a particular range is formed on the surfaces. The average value of the height of the above protrusions is 2% to 19% of the average particle diameter of the above lithium-containing silicon oxide particles.Type: ApplicationFiled: December 17, 2009Publication date: October 6, 2011Applicant: NEC ENERGY DEVICES, LTD.Inventors: Jiro Iriyama, Ryuichi Kasahara, Tetsuya Kajita, Tatsuji Numata
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Publication number: 20100173201Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0?a1?1, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2<0.3, and the z2 satisfies 0<z2<2.Type: ApplicationFiled: March 17, 2010Publication date: July 8, 2010Applicant: NEC TOKIN CORPORATIONInventors: Takehiro NOGUCHI, Masaaki MATSUU, Ryuichi KASAHARA, Tatsuji NUMATA, Yutaka BANNAI
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Publication number: 20100173200Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0?a1?1, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2?0.3, and the z2 satisfies 0?z2?2.Type: ApplicationFiled: March 17, 2010Publication date: July 8, 2010Applicant: NEC TOKIN CORPORATIONInventors: Takehiro NOGUCHI, Masaaki MATSUU, Ryuichi KASAHARA, Tatsuji NUMATA, Yutaka BANNAI
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Patent number: 7556889Abstract: A life of a secondary battery is extended, increase in a resistance when storing a secondary battery at an elevated temperature is prevented, and increase in a resistance during a charge-discharge cycle is prevented. A positive electrode active material comprising a lithium manganate and a lithium nickelate are used. The lithium manganate is a compound represented by the following formula (1) or the compound in which some of Mn or O sites are replaced with another element: Li1+xMn2?xO4??(1) (in the above-shown formula (1), 0.15?x?0.24).Type: GrantFiled: May 26, 2004Date of Patent: July 7, 2009Assignee: NEC CorporationInventors: Tomokazu Kumeuchi, Tatsuji Numata, Daisuke Kawasaki
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Patent number: 7335444Abstract: A positive electrode active material containing lithium manganate having a spinel structure is used, wherein the value of a* of the L*a*b* color specification system is made to satisfy the requirement: ?3.2 ?a*??1.4. Or, the value of a* is made to satisfy the requirement: ?5.8 23 a*??4.2. Or, the value of L* is made to satisfy the requirement: 24 ?L*?27.Type: GrantFiled: September 28, 2005Date of Patent: February 26, 2008Assignee: NEC CorporationInventors: Tatsuji Numata, Yoshitada Tomioka
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Publication number: 20070248885Abstract: The invention provides a lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolysis solution containing an aprotic solvent having an electrolyte dissolved in it, wherein the negative electrodes uses an amorphous carbon material as a negative electrode active material. The amorphous carbon material has (A) an average particle diameter (median size of 7 ?m to 20 ?m inclusive as measured by a laser diffraction scattering method and (B) a particle size distribution as measured by a laser diffraction scattering method, in which distribution the ratio of particles of less than 3 ?m in diameter is 1% by mass to 10% mass inclusive, and is free of an electrical conducting material.Type: ApplicationFiled: April 19, 2007Publication date: October 25, 2007Applicant: NEC TOKIN CorporationInventors: Yutaka Bannai, Tatsuji Numata, Ryuichi Kasahara
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Publication number: 20070172734Abstract: An objective of the present invention is to provide a lithium secondary battery which can achieve a higher capacity and a longer life without reduction in a lower voltage in the battery. In the present invention, a compound represented by general formula (I) described below is used as a cathode active material, and a compound represented by general formula (II) described below is used as an anode active material; Lia1(Nix1Mn2-x1-y1M1y1)O4??(I) wherein the M1 is at least one of Ti, Si, Mg and Al, the a1 satisfies 0<a1<, the x1 satisfies 0.4?x1?0.6, and the y1 satisfies 0?y1?0.4; and Lia2M21-y2M3y2Oz2??(II) wherein the M2 is at least one of Si and Sn; the M3 is at least one of Fe, Ni and Cu, the a2 satisfies 0?a2?5, the y2 satisfies 0?y2<0.3, and the z2 satisfies 0<z2<2.Type: ApplicationFiled: January 24, 2007Publication date: July 26, 2007Inventors: Takehiro NOGUCHI, Masaaki MATSUU, Ryuichi KASAHARA, Tatsuji NUMATA, Yutaka BANNAI
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Publication number: 20070154815Abstract: A lithium secondary battery which has excellent characteristics such as energy density and electromotive force and is excellent in cycle life and storage stability is provided. The secondary battery comprises a positive electrode, a negative electrode, and an electrolyte solution comprising an aprotic solvent having at least an electrolyte dissolved therein, wherein the positive electrode comprises a lithium-manganese composite oxide having a spinel structure as a positive electrode active material, and the electrolyte solution comprises a compound represented by the general formula (1).Type: ApplicationFiled: December 14, 2004Publication date: July 5, 2007Applicant: NEC CORPORATIONInventors: Daisuke Kawasaki, Yuki Kusachi, Tatsuji Numata, Koji Utsugi
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Patent number: 7179566Abstract: A cathode active material for a secondary battery including a lithium-manganese composite oxide having a spinel structure and represented by the following general formula (I), Lia(MxMn2-x-y-zYyAz)(O4-wZw) (I), wherein 0.5?x?1.2, 0?y, 0?z, x+y+z<2, 0?a?1.2 and 0?w?1; M contains at least Co and may further contains at least one element selected from the group consisting of Ni, Fe, Cr and Cu; Y is at least one element selected lo from the group consisting of Li, Be, B, Na, Mg, Al, K and Ca; A is at least one of Ti and Si; and Z is at least one of F and Cl. When the cathode active material for the secondary battery is used as the cathode for the a secondary battery, a higher operating can be realized while suppressing the reliability reduction such as the capacity decrease after the cycles and the deterioration of the crystalline structure at a higher temperature.Type: GrantFiled: March 7, 2003Date of Patent: February 20, 2007Assignee: NEC CorporationInventors: Daisuke Kawasaki, Takehiro Noguchi, Tatsuji Numata
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Patent number: 7026070Abstract: A positive electrode active material for a secondary battery contains a spinel lithium manganese composite oxide expressed by a general formula of Lia(MxMn2?x?yAy)O4 where x and y are positive values which satisfy 0.4<x, 0<y, x+y<2, and 0<a<1.2. “M” denotes Ni and at least one metal element selected from the group consisting of Co, Fe, Cr and Cu. “A” denotes at least one metal element selected from the group consisting of Si and Ti. The ratio y of A has a value of 0.1<y in case where A includes only Ti. Accordingly, it is possible to acquire a material for the positive electrode of a lithium ion secondary battery, which has a high capacity and a high energy density with a high voltage of 4.5 V or higher with respect to Li.Type: GrantFiled: October 15, 2002Date of Patent: April 11, 2006Assignee: NEC CorporationInventors: Takehiro Noguchi, Tatsuji Numata