Patents by Inventor Yoshio Kajiura

Yoshio Kajiura 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: 6783894
    Abstract: A process for producing a porous sintered positive electrode for a secondary battery. The steps include: (a) calcining a raw material containing a lithium compound under an oxidizing atmosphere to form calcined powders; (b) mixing the calcined powders with organic fibers or organic polymer particles to form a raw mixture; (c) forming the raw mixture into a raw electrode; and (d) heating the raw electrode to remove any organic fibers or any organic polymer particles.
    Type: Grant
    Filed: April 2, 2001
    Date of Patent: August 31, 2004
    Assignee: Kao Corporation
    Inventors: Yoshio Kajiura, Tetsuya Kusakabe, Nobuyuki Isshiki
  • Patent number: 6679926
    Abstract: A lithium secondary battery including an anode and cathode containing an active material capable of incorporating and releasing lithium ions, wherein the cathode is a porous sintered material made of a lithium-transition metal oxide, the porosity of the sintered material is 15 to 60%, and the electrical conductivity is not less than 0.1 mS/cm. Since the sintered material is sufficiently sintered so that the electrical conductivity may be more than 0.1 mS/cm, the bonding power of the primary particles of the sintered material is strong, and therefore the primary particles do not come off and the electrodes do not collapse even if the sintered material expands or shrinks because of the charge/discharge. Since the mechanical strength is great, the cathode can have a larger area. The electrolyte penetrates well into the sintered material because of its 15 to 60% porosity, and consequently the internal electrical resissitivity is low.
    Type: Grant
    Filed: February 12, 2001
    Date of Patent: January 20, 2004
    Assignee: Kao Corporation
    Inventors: Yoshio Kajiura, Atsushi Suzuki, Nobuyuki Isshiki
  • Patent number: 6335121
    Abstract: Disclosed is an electrode material for secondary battery, wherein the discharge capacity is large and the change in potential during the charge/discharge is small. A carbonaceous material, wherein a value of R (degree of raphitization ), which is defined as a ratio of a Raman spectrum intensity at 1580 cm−1 to a Raman spectrum intensity at 1360 cm−1 in the Raman spectrum analysis, is not more than 4.0 and a length of crystallite (Lc) oriented along a crysatllographic c axis obtained by a wide angle X-ray diffraction method is from 25 to 35 nm, of the electrode material is obtained by calcining a material, which can be carbonized by a heat treatment, in the presence of boron nitride or silicon.
    Type: Grant
    Filed: July 9, 1998
    Date of Patent: January 1, 2002
    Assignee: Kao Corporation
    Inventors: Kuniyuki Nakanishi, Nobuyuki Isshiki, Atsushi Suzuki, Yoshio Kajiura
  • Patent number: 6287728
    Abstract: By using a porous material formed by calcining an active material as an electrode of a non-aqueous solvent secondary battery, the volume of a dead space in the electrode contained in a container of the constituted battery is reduced, thereby to increase an electric capacity per unit volume. By using the porous material as the electrode material, rather a powder material, the active material is sufficiently brought into contact with an electrolyte solution, electrically. Furthermore, the amount of a metal foil as a current collecting material and a conductive material are reduced or use of them is made unnecessary, and an electric capacity per unit weight is increased in comparison with the prior art. When the porous sintered material has a plate-like shape, the thickness is from 100 &mgr;m to 2 mm. The porous sintered material contains pores of an average diameter of 0.
    Type: Grant
    Filed: August 19, 1998
    Date of Patent: September 11, 2001
    Assignee: Kao Corporation
    Inventors: Yoshio Kajiura, Tetsuya Kusakabe, Nobuyuki Isshiki
  • Publication number: 20010019798
    Abstract: By using a porous material formed by calcining an active material as an electrode of a non-aqueous solvent secondary battery, the volume of a dead space in the electrode contained in a container of the constituted battery is reduced, thereby to increase an electric capacity per unit volume. By using the porous material as the electrode material, rather a powder material, the active material is sufficiently brought into contact with an electrolyte solution, electrically. Furthermore, the amount of a metal foil as a current collecting material and a conductive material are reduced or use of them is made unnecessary, and an electric capacity per unit weight is increased in comparison with the prior art. When the porous sintered material has a plate-like shape, the thickness is from 100 &mgr;m to 2 mm. The porous sintered material contains pores of an average diameter of 0.
    Type: Application
    Filed: April 2, 2001
    Publication date: September 6, 2001
    Applicant: Kao Corporation
    Inventors: Yoshio Kajiura, Tetsuya Kusakabe, Nobuyuki Isshiki