Patents by Inventor Masatoshi Nagayama

Masatoshi Nagayama 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).

  • Publication number: 20080213668
    Abstract: A nonaqueous electrolyte secondary battery has a positive electrode including an active material of complex oxides capable of storing and emitting lithium ions, a negative electrode, a separator, and an electrolytic solution made of a nonaqueous solvent. A discharge curve of this battery when being discharged with a constant power has two or more points of step-like flections near the end of electrical discharge in a range of 5% to 20% of a discharge capacity thereof as determined from an initial discharge voltage in a state of full charge to a discharge-end voltage.
    Type: Application
    Filed: January 13, 2006
    Publication date: September 4, 2008
    Inventors: Yoshiyuki Muraoka, Takuya Nakashima, Kiyomi Kozuki, Masatoshi Nagayama
  • Publication number: 20080193844
    Abstract: The present invention provides a high-capacity and low-cost non-aqueous electrolyte secondary battery, comprising: a negative electrode containing, as a negative electrode active material, a substance capable of absorbing/desorbing lithium ions and/or metal lithium; a separator; a positive electrode; and an electrolyte, wherein the positive electrode active material contained in the positive electrode is composed of crystalline particles of an oxide containing two kinds of transition metal elements, the crystalline particles having a layered crystal structure, and oxygen atoms constituting the oxide forming a cubic closest packing structure.
    Type: Application
    Filed: January 14, 2008
    Publication date: August 14, 2008
    Applicants: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., OSAKA CITY UNIVERSITY
    Inventors: Tsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama
  • Patent number: 7381497
    Abstract: A positive electrode active material for a non-aqueous electrolyte secondary battery, comprising a lithium-containing composite oxide, wherein the composite oxide is represented by the general formula: LizCo1-x-yMgxMyO2, the element M included in the general formula is at least one selected from the group consisting of Al, Ti, Sr, Mn, Ni and Ca, the values x, y and z included in the general formula satisfy: (i) 0?z?1.03; (ii) 0.005?x?0.1; and (iii) 0.001?y?0.03, the composite oxide has a crystal structure attributed to a hexagonal system in an overcharged state having a potential over 4.25 V relative to metallic Li, and a maximum value of an oxygen generation peak in a gas chromatograph mass spectrometry measurement of the composite oxide in the overcharged state is in the range of 330 to 370° C.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: June 3, 2008
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masatoshi Nagayama, Hiroshi Yoshizawa
  • Publication number: 20080096111
    Abstract: The present invention provides a high-capacity and low-cost non-aqueous electrolyte secondary battery, comprising: a negative electrode containing, as a negative electrode active material, a substance capable of absorbing/desorbing lithium ions and/or metal lithium; a separator; a positive electrode; and an electrolyte, wherein the positive electrode active material contained in the positive electrode is composed of crystalline particles of an oxide containing two kinds of transition metal elements, the crystalline particles having a layered crystal structure, and oxygen atoms constituting the oxide forming a cubic closest packing structure.
    Type: Application
    Filed: October 25, 2007
    Publication date: April 24, 2008
    Applicants: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., OSAKA CITY UNIVERSITY
    Inventors: Tsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama
  • Publication number: 20080032199
    Abstract: In a non-aqueous electrolyte secondary battery comprising: a negative electrode containing, as a negative electrode active material, at least a material capable of absorbing and desorbing lithium ions or metal lithium; a positive electrode; and an electrolyte, an oxide containing nickel and manganese elements, the material comprising primary particles of the oxide having a twining portion and a superlattice arrangement of a [3×3] R30° when assigned as R3-m is used as a positive electrode active material.
    Type: Application
    Filed: August 3, 2007
    Publication date: February 7, 2008
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Tsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama
  • Publication number: 20070207383
    Abstract: The present invention relates to a positive electrode active material comprising a lithium-containing composite oxide containing nickel with an oxidation state of 2.0 to 2.5 and manganese with an oxidation state of 3.5 to 4.0, the oxidation state determined by the shifts of energy at which absorption maximum is observed in the X-ray absorption near-K-edge structures, and to a non-aqueous electrolyte secondary battery using the same, the positive electrode active material being characterized in having a high capacity, a long storage life and excellent cycle life.
    Type: Application
    Filed: May 1, 2007
    Publication date: September 6, 2007
    Applicant: Osaka City University
    Inventors: Tsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama
  • Patent number: 7255963
    Abstract: A non-aqueous electrolyte rechargeable battery including: (a) a positive electrode capable of charging and discharging lithium; (b) a negative electrode capable of charging and discharging lithium; (c) a separator or a lithium ion conductive layer interposed between the positive electrode and the negative electrode; and (d) a lithium ion conductive non-aqueous electrolyte, wherein the positive electrode contains a mixture of a first positive electrode active material and a second positive electrode active material, the first positive electrode active material includes lithium oxide containing manganese, the lithium oxide further contains aluminum and/or magnesium, and the second positive electrode active material includes LixCo1-y-zMgyAlzO2 where 1?x?1.03, 0.005?y?0.1 and 0.001?z<0.02.
    Type: Grant
    Filed: December 9, 2003
    Date of Patent: August 14, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masatoshi Nagayama, Hiroshi Yoshizawa
  • Publication number: 20070184337
    Abstract: A battery operated device is equipped with one or more batteries each including a positive electrode, a negative electrode, a separator, and an electrolyte in a battery case. In this battery operated device, the battery has a gas vent that is opened due to an increase in pressure inside the battery case, and is configured to dispose the gas vent at a lower position thereof when installed in the battery operated device. Therefore, the battery function is ceased due to actuation of the gas vent.
    Type: Application
    Filed: January 10, 2007
    Publication date: August 9, 2007
    Inventors: Masatoshi Nagayama, Tsuyoshi Hatanaka, Hideaki Fujita
  • Publication number: 20070166607
    Abstract: An assembled battery comprises mainly multiple non-aqueous secondary cells A and at least one electric device B for voltage detection containing a non-aqueous electrolyte connected to the multiple non-aqueous secondary cells A in series. When a difference in the non-aqueous secondary cell A between a voltage per cell (VA1) at a depth of discharge of 25% and a voltage per cell (VA2) at a depth of discharge of 75% is designated as ?VA, and a difference in the electric device B between a voltage per cell (VB1) at a depth of discharge equivalent to the depth of discharge of 25% of the non-aqueous secondary cell A and a voltage per cell (VB2) at a depth of discharge equivalent to the depth of discharge of 75% of the non-aqueous secondary cell A is designated as ?VB, the ?VB of electric device B is greater than the ?VA of non-aqueous secondary cell A.
    Type: Application
    Filed: January 18, 2007
    Publication date: July 19, 2007
    Inventors: Yukihiro Okada, Masatoshi Nagayama
  • Publication number: 20070166610
    Abstract: A non-aqueous electrolyte battery has a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode has a high-capacity positive electrode portion with a plate area per capacity of smaller than 200 cm2/Ah, and a high-power positive electrode portion with a plate area per capacity of 200 cm2/Ah or larger. The non-aqueous electrolyte battery is advantageous in providing a battery, with use of a single kind of non-aqueous electrolyte battery, which simultaneously satisfies the requirements on high-capacity characteristics capable of performing a long-term continuous discharge, and on high-power characteristics capable of performing a pulse discharge at a large current, without using a hybrid power supply unit which has multiple kinds of batteries and requires a complex control system.
    Type: Application
    Filed: January 16, 2007
    Publication date: July 19, 2007
    Inventors: Takuya Nakashima, Masatoshi Nagayama, Yoshiyuki Muraoka
  • Publication number: 20070048615
    Abstract: A non-aqueous electrolyte secondary battery includes an electrode assembly formed by winding positive and negative electrodes, and an insulating layer together. Each of the electrodes has a core sheet and mixture layers formed on both sides of the sheet. The insulating layer electrically insulates the electrodes. At least one of the electrodes includes a core-exposed portion continuous parallel to the winding direction. Each of the mixture layers has an inclined weight region where the amount of mixture per unit area decreases toward the core-exposed portion, and a constant weight region in which the amount of mixture per unit area is constant. The inclined weight region has a width of not more than 0.2 of the width of the mixture layers and has an average mixture density of not less than 40% and not more than 99% of the mixture density of the constant weight region.
    Type: Application
    Filed: July 25, 2006
    Publication date: March 1, 2007
    Inventors: Masatoshi Nagayama, Takuya Nakashima, Yoshiyuki Muraoka
  • Publication number: 20070042274
    Abstract: A non-aqueous electrolyte secondary battery has a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte solution. The positive electrode has a theoretical capacity per unit area from 3.0 to 4.5 mAh/cm2. The non-aqueous electrolyte solution contains ethylene carbonate (EC), ethylmethyl carbonate (EMC), and dimethyl carbonate (DMC) as solvents, and LiPF6 as an electrolyte, with volume ratios from 10 to 20% for EC, 10 to 20% for EMC, and 60 to 80% for DMC relative to all the solvents in the electrolyte solution. The concentration of the LiPF6 is from 1.30 to 1.50 mol/L.
    Type: Application
    Filed: August 17, 2006
    Publication date: February 22, 2007
    Inventors: Yoshiyuki Muraoka, Takuya Nakashima, Kiyomi Kouzuki, Masatoshi Nagayama
  • Publication number: 20070009424
    Abstract: A positive electrode active material for a non-aqueous electrolyte battery comprising a lithium-containing transition metal oxide, produced with the use of a dry precursor obtained by: introducing an alkaline solution together with an aqueous solution containing two or more of transition metal salts or two kinds or more of aqueous solutions of different transition metal salts into a reaction vessel to obtain a hydroxide or an oxide as a precursor through coprecipitation with a reductant being coexistent or an inert gas being supplied; and drying the precursor at 300 to 500° C. to obtain a dry precursor.
    Type: Application
    Filed: September 14, 2006
    Publication date: January 11, 2007
    Applicants: OSAKA CITY UNIVERSITY, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Tsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama
  • Patent number: 7157186
    Abstract: A method of producing a positive electrode active material for a non-aqueous electrolyte secondary battery, comprising the steps of: (a) preparing a raw material mixture, comprising “nx” mol of magnesium, “ny” mol of an element M where the element M is at least one selected from the group consisting of Al, Ti, Sr, Mn, Ni and Ca, “n(1?x?y)” mol of cobalt and “nz” mol of lithium, such that the values n, x, y and z satisfy 0<n, 0.97?(1/z)?1, 0.005?x?0.1, and 0.001?y?0.03; and (b) baking the raw material mixture in an oxidization atmosphere at 1000 to 1100° C.
    Type: Grant
    Filed: January 5, 2004
    Date of Patent: January 2, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masatoshi Nagayama, Hiroshi Yoshizawa
  • Patent number: 7150940
    Abstract: A lithium ion secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein the positive electrode comprises a positive electrode active material, a conductive agent and a binder, the positive electrode active material comprises a lithium-containing composite oxide represented by the formula Lia(Co1?x?yMgxMy)bOc, where M is at least one selected from Ni and Al, 0?a?1.05, 0.03?x?0.15, 0?y?0.25, 0.85?b?1.1 and 1.8?c?2.1, and the amount of the conductive agent contained in the positive electrode is not more than 3.0 parts by weight per 100 parts by weight of the positive electrode active material.
    Type: Grant
    Filed: October 21, 2002
    Date of Patent: December 19, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masaya Okochi, Masatoshi Nagayama, Yutaka Kawatate, Ryoichi Tanaka, Hideya Asano
  • Publication number: 20060275664
    Abstract: In order to provide a 3V level non-aqueous electrolyte secondary battery with a flat voltage and excellent cycle life at a high rate with low cost, the present invention provides a positive electrode represented by the formula: Li2±?[Me]4O8?x, wherein 0??<0.4, 0?x<2, and Me is a transition metal containing Mn and at least one selected from the group consisting of Ni, Cr, Fe, Co and Cu, said active material exhibiting topotactic two-phase reactions during charge and discharge.
    Type: Application
    Filed: May 11, 2006
    Publication date: December 7, 2006
    Inventors: Tsutomu Ohzuku, Hiroshi Yoshizawa, Masatoshi Nagayama, Hizuru Koshina
  • Publication number: 20060269842
    Abstract: A non-aqueous electrolyte secondary battery including an electrode assembly, a non-aqueous electrolyte, and a substantially rectangular battery case for housing the electrode assembly and the non-aqueous electrolyte. The thickness ?, the width ?, and the height ? of the battery case satisfy the relation ?<???c. The electrode assembly includes a positive electrode, a negative electrode, and a porous heat-resistant layer disposed between these electrodes. The positive electrode includes a positive electrode active material layer, and the negative electrode includes a negative electrode active material layer. The ratio of the pore volume included in a predetermined area of the porous heat-resistant layer to the battery theoretical capacity is 0.18 to 1.117 ml/Ah. The predetermined area has the same area as the positive electrode active material layer. The porosity of the porous heat-resistant layer is 35 to 85%.
    Type: Application
    Filed: May 31, 2006
    Publication date: November 30, 2006
    Inventors: Hiroaki Ichinose, Masatoshi Nagayama
  • Publication number: 20060251963
    Abstract: To provide a high power non-aqueous electrolyte secondary battery with high performance and less degradation in capacity even when high power discharge is repeated while maintaining the initial output characteristic by optimizing the insulating structure between the positive and negative electrodes, in a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, a microporous resin separator and an electrolyte, an area per theoretical capacity of the positive electrode is set to 190 to 800 cm2/Ah and a porous heat-resistant layer having a thickness of 10 to 60 ?m is provided between the separator and at least one of the positive electrode and the negative electrode.
    Type: Application
    Filed: April 4, 2006
    Publication date: November 9, 2006
    Inventors: Takuya Nakashima, Masatoshi Nagayama, Yoshiyuki Muraoka
  • Patent number: 7122278
    Abstract: A non-aqueous electrolyte secondary battery provided with a positive electrode having a lithium-manganese composite oxide as a positive electrode material, a negative electrode comprising a material capable of absorbing and releasing lithium and a non-aqueous electrolyte can be inhibited from deterioration of the negative electrode and can maintain excellent battery performances even after stored in a high-temperature environment or subjected to charging and discharging cycles at high temperatures by containing at least one of sodium (Na), potassium (K), calcium (Ca) and strontium (Sr).
    Type: Grant
    Filed: June 21, 2000
    Date of Patent: October 17, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takuya Nakashima, Shinji Arimoto, Masatoshi Nagayama, Yoshiaki Nitta
  • Publication number: 20060194109
    Abstract: A non-aqueous electrolyte secondary battery including: a positive electrode including a positive electrode material mixture layer; a negative electrode including a negative electrode material mixture layer; a separator or lithium-ion conductive porous film interposed between the positive electrode and the negative electrode; and a lithium-ion conductive non-aqueous electrolyte. The positive electrode material mixture layer contains a positive electrode active material comprising a lithium transition metal composite oxide, and the lithium transition metal composite oxide contains lithium, a transition metal, and a metal different from the transition metal. The negative electrode material mixture layer contains a negative electrode active material comprising a carbon material. In the area where the positive electrode material mixture layer and the negative electrode material mixture layer are opposed to each other, the ratio R:Wp/Wn is 1.3 to 2.
    Type: Application
    Filed: May 11, 2004
    Publication date: August 31, 2006
    Inventors: Shoichiro Watanabe, Masatoshi Nagayama, So Kuranaka