Patents by Inventor Takafumi Oura
Takafumi Oura 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: 8367252Abstract: A non-aqueous electrolyte secondary battery wherein the non-aqueous electrolyte contains a non-aqueous solvent, a solute dissolved in the non-aqueous solvent, and hydrogenated terphenyl, the solute includes a boron-containing alkali salt and a boron-free alkali salt, the negative electrode includes a negative electrode active material comprising a randomly oriented carbon composite (A), and the carbon composite (A) contains a graphitic carbon substance (B) and a carbon substance (C) that is different from the graphitic carbon substance (B).Type: GrantFiled: February 23, 2007Date of Patent: February 5, 2013Assignees: Panasonic Corporation, Mitsubishi Chemical CorporationInventors: Takaharu Morikawa, Atsushi Ueda, Takafumi Oura, Shinichi Kinoshita, Minoru Kotato, Hideharu Satou, Hitoshi Matsumoto
-
Patent number: 8277520Abstract: One aspect of the present invention pertains to a method for producing a negative electrode for a non-aqueous electrolyte secondary battery, which comprises a paste preparing step of kneading a mixture containing a negative electrode active material, a binder resin having a glass transition temperature within a range from 20 to 40° C. and a dispersion solvent to prepare a negative electrode material mixture paste, a paste applying step of applying the negative electrode material mixture paste controlled to a temperature which is at least 10° C. higher than the glass transition temperature of the binder resin on a current collector to form a coating film, a coating film drying step of drying the coating film to form a negative electrode precursor, and a rolling step of rolling the negative electrode precursor to prepare a negative electrode having a negative electrode material mixture layer.Type: GrantFiled: November 27, 2007Date of Patent: October 2, 2012Assignee: Panasonic CorporationInventors: Toshihiro Inoue, Masao Fukunaga, Takafumi Oura
-
Publication number: 20100227218Abstract: A non-aqueous electrolyte secondary battery wherein the non-aqueous electrolyte contains a non-aqueous solvent, a solute dissolved in the non-aqueous solvent, and hydrogenated terphenyl, the solute includes a boron-containing alkali salt and a boron-free alkali salt, the negative electrode includes a negative electrode active material comprising a randomly oriented carbon composite (A), and the carbon composite (A) contains a graphitic carbon substance (B) and a carbon substance (C) that is different from the graphitic carbon substance (B).Type: ApplicationFiled: February 23, 2007Publication date: September 9, 2010Inventors: Takaharu Morikawa, Atsushi Ueda, Takafumi Oura, Shinichi Kinoshita, Minoru Kotato, Hideharu Satou, Hitoshi Matsumoto
-
Patent number: 7674556Abstract: A non-aqueous electrolyte secondary battery comprises a negative electrode including a negative electrode active material, a positive electrode including a positive electrode active material, and a non-aqueous electrolyte; the positive electrode active material is LiNi1-y-zMnyCozO2, wherein y and z satisfy 0<y?0.5, 0?z?0.5, and 0<y+z?0.75; and an upper limit voltage for charging the non-aqueous electrolyte secondary battery is 4.25 to 4.70 V. It is possible to obtain a non-aqueous electrolyte secondary with high capacity, high reliability, and long life by properly setting the composition of a composite oxide of lithium which is a positive electrode active material and the charging conditions of the battery using this composite oxide of lithium as a positive electrode active material as described above.Type: GrantFiled: May 28, 2003Date of Patent: March 9, 2010Assignee: Panasonic CorporationInventors: Kensuke Nakura, Takafumi Oura, Mitsuhiro Takeno, Shuji Tsutsumi, Kazuhiro Okamura
-
Publication number: 20080124628Abstract: An object of the present invention is to provide a method for producing a negative electrode for a non-aqueous electrolyte secondary battery capable of forming a negative electrode material mixture layer which is less likely to fall or peel from a negative electrode current collector. One aspect of the present invention pertains to a method for producing a negative electrode for a non-aqueous electrolyte secondary battery, which comprises a paste preparing step of kneading a mixture containing a positive electrode active material for a non-aqueous negative electrode active material, a binder resin having a glass transition temperature within a range from 20 to 40° C. and a dispersion solvent to prepare a negative electrode material mixture paste, a paste applying step of applying the negative electrode material mixture paste controlled to a temperature which is at least 10° C.Type: ApplicationFiled: November 27, 2007Publication date: May 29, 2008Inventors: Toshihiro INOUE, Masao Fukunaga, Takafumi Oura
-
Publication number: 20070254215Abstract: Disclosed is a non-aqueous electrolyte containing a non-aqueous solvent, a solute dissolved in the non-aqueous solvent, and a hydrogenated terphenyl. The solute comprises an alkali salt containing boron and an alkali salt containing no boron. An amount of the hydrogenated terphenyl contained in the non-aqueous electrolyte is preferably 0.5 mass % to 3.5 mass %. For example, LiBF4, NaBF4 or KBF4 is used as the alkali salt containing boron, while LiPF6, LiClO4, LiAsF6, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2C2F5)2 or LiC(SO2CF3)3 is used as the alkali salt containing no boron.Type: ApplicationFiled: August 29, 2005Publication date: November 1, 2007Inventors: Takaharu Morikawa, Takafumi Oura, Atsushi Otsuka, Shinichi Kinoshita, Minoru Kotato
-
Patent number: 7052803Abstract: The present invention provides a lithium rechargeable battery including a negative electrode comprising a copper core material, to which is fixed an active material made by mixing artificial graphite particles A obtained by kneading and granulating a base material of pulverized bulk mesophase pitch with pitch in a softened state and/or thermosetting resin, carbonizing the resulting granules at 700 to 1,500° C. and graphitizing the carbonized granules at 2,500 to 3,000° C. with spherical graphite particles B having a high mean circularity, with a view to inhibiting the deterioration in battery capacity through the repeated charge/discharge cycles, which occurs remarkably in a high energy density lithium rechargeable battery, and providing excellent discharge characteristic and safety.Type: GrantFiled: July 17, 2003Date of Patent: May 30, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Fumio Kato, Takafumi Oura, Yusuke Fukumoto, Norihiro Yamamoto, Shozo Fujiwara
-
Patent number: 7026073Abstract: In an electrolyte of a non-aqueous electrolyte secondary battery using a cyclic carboxylic-acid ester exerting high conductivity under a low temperature condition, for suppressing reductive decomposition of the cyclic carboxylic acid ester, a cyclic carbonic acid ester having at least one carbon-carbon unsaturated bond is contained, and for suppressing excessive polymerization reaction of the cyclic carbonic acid ester having at least one carbon-carbon unsaturated bond, a cyclic carbonic acid ester having no carbon-carbon unsaturated bond is further contained.Type: GrantFiled: January 28, 2002Date of Patent: April 11, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Atsushi Ueda, Kazuya Iwamoto, Takafumi Oura, Hiroshi Yoshizawa, Masaki Deguchi, Takaharu Morikawa
-
Patent number: 6958198Abstract: The invention relates to a non-aqueous electrochemical apparatus in which the difference (?l??se) between the surface tension ?l of non-aqueous electrolyte and the surface free energy ?se of electrode is not more than 10 dynes/cm.Type: GrantFiled: July 10, 2001Date of Patent: October 25, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kazuya Iwamoto, Takafumi Oura, Kumiko Sonoda, Makino Hatazaki, Hiroshi Yoshizawa, Shinji Nakanishi
-
Patent number: 6806004Abstract: A polymeric solid electrolyte capable of conducting lithium ions which contains silylamide bonds in its polymer skeleton structure, for example, which is obtained by a method comprising subjecting a mixture of lithium silylamide and an organic compound having at least one carbon—carbon double bond to a polymerization in a dry atmosphere; and a lithium secondary cell using the polymeric solid electrolyte. The polymeric solid electrolyte is a “dry” polymeric solid electrolyte which contains counter ions forming lithium salts with lithium ions in its polymer skeleton structure and thus has a single ion electron conducting system wherein lithium ions alone are mobile ions, and hence has excellent conductivity, and further is easy to produce.Type: GrantFiled: July 31, 2001Date of Patent: October 19, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kazuya Iwamoto, Takafumi Oura, Shinji Nakanishi, Atsushi Ueda, Hizuru Koshina
-
Patent number: 6723473Abstract: In a non-aqueous electrolyte secondary battery, a cyclic carboxylic acid ester having a high conductivity in a low-temperature environment is used as an electrolyte, and, furthermore, a cyclic carbonic acid ester having at least one carbon-carbon unsaturated bond is added thereto for the inhibition of reductive decomposition of the cyclic carboxylic acid ester.Type: GrantFiled: November 14, 2001Date of Patent: April 20, 2004Assignees: Matsushita Electric Industrial Co., Ltd., Mitsubishi Chemical CorporationInventors: Takafumi Oura, Kazuya Iwamoto, Shinji Nakanishi, Atsushi Ueda, Hizuru Koshina
-
Patent number: 6713217Abstract: The present invention relates to a nonaqueous electrolyte secondary battery, and more particularly to its separator, and it is an object thereof to prevent electrolyte leakage accident due to elevation of cell internal pressure even if the cell is exposed to high temperature without sacrificing the cell capacity. To achieve the object, by using the polyolefin group separator large in endothermic calorie per unit area by the heat of fusion in a temperature range of 70 to 150° C., and selecting appropriate graphite powder for negative electrode and organic solvent in nonaqueous electrolyte, the electrolyte leakage accident can be successfully eliminated by suppressing the reaction between the cell active substance and organic solvent, thereby suppressing elevation of cell internal pressure.Type: GrantFiled: January 8, 1998Date of Patent: March 30, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takafumi Oura, Masaki Kitagawa, Hajime Nishino, Hizuru Koshina
-
Publication number: 20040023115Abstract: The present invention provides a lithium rechargeable battery including a negative electrode comprising a copper core material, to which is fixed an active material made by mixing artificial graphite particles A obtained by kneading and granulating a base material of pulverized bulk mesophase pitch with pitch in a softened state and/or thermosetting resin, carbonizing the resulting granules at 700 to 1,500° C. and graphitizing the carbonized granules at 2,500 to 3,000° C. with spherical graphite particles B having a high mean circularity, with a view to inhibiting the deterioration in battery capacity through the repeated charge/discharge cycles, which occurs remarkably in a high energy density lithium rechargeable battery, and providing excellent discharge characteristic and safety.Type: ApplicationFiled: July 17, 2003Publication date: February 5, 2004Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.Inventors: Fumio Kato, Takafumi Oura, Yusuke Fukumoto, Norihiro Yamamoto, Shozo Fujiwara
-
Publication number: 20030228519Abstract: A non-aqueous electrolyte secondary battery comprises a negative electrode including a negative electrode active material, a positive electrode including a positive electrode active material, and a non-aqueous electrolyte; the positive electrode active material is LiNi1-y-zMnyCozO2, wherein y and z satisfy 0<y≦0.5, 0≦z≦0.5, and 0<y+z≦0.75; and an upper limit voltage for charging the non-aqueous electrolyte secondary battery is 4.25 to 4.70 V.Type: ApplicationFiled: May 28, 2003Publication date: December 11, 2003Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Kensuke Nakura, Takafumi Oura, Mitsuhiro Takeno, Shuji Tsutsumi, Kazuhiro Okamura
-
Patent number: 6645667Abstract: A lithium secondary cell comprising a safe aqueous-solution electrolyte free from danger of firing and explosion and capable of supplying a high voltage of more than 3 V. The cell includes a positive plate having an active material absorbing/desorbing lithium ions and exhibiting a high voltage, a negative plate having an active material exhibiting a low voltage, a polymer solid electrolyte having a lithium-ionic conductivity, and an aqueous-solution electrolyte. The positive and negative plates are coated with a polymer solid electrolyte having an ionic conductivity and therefore isolated from the aqueous-solution electrolyte by the plate coating layers.Type: GrantFiled: July 13, 2001Date of Patent: November 11, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kazuya Iwamoto, Takafumi Oura, Shinji Nakanishi, Atsushi Ueda, Hizuru Koshina
-
Patent number: 6630272Abstract: The present invention relates to an electrolyte for non-aqueous electrochemical device containing at least one of 6-substituted-1,3,5-triazine-2,4-dithiol and derivatives thereof as an additive and a non-aqueous electrochemical device, particularly a lithium secondary battery by the use thereof. The additive of the present invention forms a stable and low resistance film on the positive electrode, inhibiting characteristics of the electrochemical device from deteriorating on account of gas generated due to the decomposition of electrolyte.Type: GrantFiled: May 18, 2001Date of Patent: October 7, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kazuya Iwamoto, Takafumi Oura, Shinji Nakanishi, Atsushi Ueda, Hizuru Koshina
-
Patent number: 6589689Abstract: For providing a non-aqueous electrolyte secondary battery having excellent storage characteristics when stored in the charged state under a high temperature condition, the non-aqueous electrolyte or the negative electrode is made to contain divinylethylene carbonate, thereby to form a film derived from divinylethylene carbonate on the surface of the negative electrode material.Type: GrantFiled: April 10, 2001Date of Patent: July 8, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Takafumi Oura, Kazuya Iwamoto, Atsushi Ueda, Hiroshi Yoshizawa
-
Publication number: 20020192565Abstract: In an electrolyte of a non-aqueous electrolyte secondary battery using a cyclic carboxylic-acid ester exerting high conductivity under a low temperature condition, for suppressing reductive decomposition of the cyclic carboxylic acid ester, a cyclic carbonic acid ester having at least one carbon-carbon unsaturated bond is contained, and for suppressing excessive polymerization reaction of the cyclic carbonic acid ester having at least one carbon-carbon unsaturated bond, a cyclic carbonic acid ester having no carbon-carbon unsaturated bond is further contained.Type: ApplicationFiled: January 28, 2002Publication date: December 19, 2002Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Atsushi Ueda, Kazuya Iwamoto, Takafumi Oura, Hiroshi Yoshizawa, Masaki Deguchi, Takaharu Morikawa
-
Publication number: 20020039677Abstract: The invention relates to a non-aqueous electrochemical apparatus in which the difference (&ggr;l-&ggr;se) between the surface tension &ggr;l of non-aqueous electrolyte and the surface free energy &ggr;se of electrode is not more than 10 dynes/cm.Type: ApplicationFiled: July 10, 2001Publication date: April 4, 2002Inventors: Kazuya Iwamoto, Takafumi Oura, Kumiko Sonoda, Makino Hatazaki, Hiroshi Yoshizawa, Shinji Nakanishi
-
Publication number: 20010053474Abstract: For providing a non-aqueous electrolyte secondary battery having excellent storage characteristics when stored in the charged state under a high temperature condition, the non-aqueous electrolyte or the negative electrode is made to contain divinylethylene carbonate, thereby to form a film derived from divinylethylene carbonate on the surface of the negative electrode material.Type: ApplicationFiled: April 10, 2001Publication date: December 20, 2001Applicant: Matsushita Electric Industrial Co., Ltd.Inventors: Takafumi Oura, Kazuya Iwamoto, Atsushi Ueda, Hiroshi Yoshizawa