Patents by Inventor Mayumi Uehara

Mayumi Uehara 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: 5650244
    Abstract: A nonaqueous electrolyte battery comprises a positive electrode, a negative electrode with lithium as active material, a nonaqueous electrolyte comprising a solute and a solvent, and a separator, the nonaqueous electrolyte further comprising 3.times.10.sup.-4 to 3.times.10.sup.-2 mole/liter, preferably 1.5.times.10.sup.-3 to 6.times.10.sup.-3 mole/liter of a specific calcium salt. This battery, with the nonaqueous electrolyte incorporating the specific calcium in the specific amount, causes little self-discharge during storage, thus having excellent storage stability.
    Type: Grant
    Filed: August 25, 1995
    Date of Patent: July 22, 1997
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoshihiro Shoji, Mayumi Uehara, Koji Nishio, Toshihiko Saito
  • Patent number: 5626985
    Abstract: A nonaqueous electrolyte battery comprising a positive electrode, a negative electrode having lithium as an active material, a nonaqueous electrolyte comprising a solute and a solvent, and a separator. The solvent is a mixed solvent consisting essentially of 5 to 50% by volume of cyclic carbonate, 5 to 50% by volume of chain carbonate and 40 to 80% by volume of ether. The mixed solvent of a specific composition is less likely to cause undesirable surface layer formation on the negative electrode so that the electric resistance of the interface between the negative electrode and nonaqueous electrolyte is kept small. The nonaqueous electrolyte battery of the invention can therefore deliver a large amount of current and provide a high discharge capacity at low temperatures.
    Type: Grant
    Filed: August 25, 1995
    Date of Patent: May 6, 1997
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yoshihiro Shoji, Mayumi Uehara, Koji Nishio, Toshihiko Saito
  • Patent number: 5443929
    Abstract: Provided is a nonaqueous battery having an active material of a positive electrode formed from a composite powder consisting of Li.sub.1-x Mn.sub.2 O.sub.4 (0.ltoreq.X.ltoreq.1) and Li.sub.2 MnO.sub.3. Because the active material has the form of a composite, this battery allows little of the manganese to dissolve out during charge and hence has excellent charge-discharge characteristics.
    Type: Grant
    Filed: August 16, 1993
    Date of Patent: August 22, 1995
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yuji Yamamoto, Toshiyuki Nohma, Hiroshi Kurokawa, Mayumi Uehara, Koji Nishio, Toshihiko Saito
  • Patent number: 5308720
    Abstract: A non-aqueous battery has a positive electrode having a composition essentially represented by a formula LixNiOy (0<x<1.3 and 1.8<y<2.2), a negative electrode having a material which occludes and releases lithium reversibly and a non-aqueous electrolyte. The composition has a ratio of I.sub.104 to I.sub.003 ranging from 0.35 to 0.68 when measured by an X-ray powder diffraction method using CuK.sub..mu. as a target. The I.sub.104 represents a peak intensity of reflection of X-rays at an angle about 2.theta.=44 degrees with respect to the lattice plane (104), and the I.sub.003 representing another peak intensity of reflection of X-rays at an angle about 2.theta.=19 degrees with respect to the lattice plane (003).
    Type: Grant
    Filed: August 5, 1993
    Date of Patent: May 3, 1994
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Hiroshi Kurokawa, Toshiyuki Nohma, Yuuji Yamamoto, Mayumi Uehara, Koji Nishio, Toshihiko Saitoh