Patents by Inventor Keitaro Katsu

Keitaro Katsu 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: 6324049
    Abstract: An electric double layer capacitor is formed by stacking one or a plurality of basic cells each having a pair of polarized electrodes, collectors, and a gasket unit. The polarized electrodes oppose each other via a separator made from a porous material soaked in a water-based electrolytic solution such as sulfuric acid. The collectors contact surfaces of the polarized electrodes away from surfaces in contact with the separator. The gasket unit is so arranged as to surround peripheral end faces of the polarized electrodes with a predetermined spacing therebetween. In this electric double layer capacitor, a peripheral portion of the separator projecting from the polarized electrode end faces is surrounded by another material.
    Type: Grant
    Filed: December 8, 1997
    Date of Patent: November 27, 2001
    Assignee: NEC Corporation
    Inventors: Masako Inagawa, Keitaro Katsu, Yoshiki Inoue
  • Patent number: 5959830
    Abstract: A stack type electric double layer capacitor includes a plurality of unit cells, each with a pair of polarizing electrodes facing each other across a porous separator, a pair of current collecting members, and a gasket surrounding the electrodes and current collecting members. The gasket has a heat radiation notch in the direction parallel to or perpendicular to the stacking direction. This prevents heat from accumulating in the capacitor at the time of rapid charge and discharge, and thereby enhances the reliability of the capacitor.
    Type: Grant
    Filed: July 30, 1997
    Date of Patent: September 28, 1999
    Assignee: NEC Corporation
    Inventors: Masako Inagawa, Munekazu Aoki, Keitaro Katsu
  • Patent number: 5859761
    Abstract: An electric double-layer capacitor is provided, which decreases the number of necessary components to improve the productivity of the capacitor. The capacitor includes at least one basic cell. Each of the at least one basic cell has (a) an insulative, tubular gasket having a tubular inner space and opening ends, (b) a pair of polarizable electrodes made of a solid activated-carbon, (c) a sheet-like, porous, non electron-conductive separator sandwiched between the pair of electrodes; and (d) a pair of conductive, sheet-like collectors placed to close the opening ends of the gasket. The pair of collectors are electrically connected to a pair of external terminals. The pair of electrodes and the separator are placed in the inner space of the gasket. The gasket is made of a thermoplastic resin and is formed by injection molding. The separator and the pair of electrodes are unified with the gasket.
    Type: Grant
    Filed: March 28, 1997
    Date of Patent: January 12, 1999
    Assignee: NEC Corporation
    Inventors: Munekazu Aoki, Keitaro Katsu
  • Patent number: 5786981
    Abstract: A basic cell for an electric double layer capacitor has a pair of polarizing electrodes each including a plurality of chip electrodes arranged in matrix or honeycomb pattern. The plurality of chip electrodes are electrically connected by direct contact between each adjacent two chip electrodes for increasing the capacitance and decreasing the internal resistance. Excellent charging or discharging characteristic can be obtained even if the sheet collectors for providing charging or discharging current for the chip electrodes have different specific resistivities along the surface of the sheet collectors. The chip electrodes may be of a truncated pyramid shape for improving resistance against distorting or bending stress applied to the basic cell.
    Type: Grant
    Filed: February 19, 1997
    Date of Patent: July 28, 1998
    Assignee: NEC Corporation
    Inventors: Munekazu Aoki, Masako Inagawa, Keitaro Katsu
  • Patent number: 5781403
    Abstract: An electric double layer capacitor including a pair of activated charcoal electrodes facing each other with the intermediary of a porous separator, and current collecting members each being positioned on a surface of the respective electrode opposite to a surface contacting the separator is disclosed. Hydrophobic powdery activated charcoal is provided around the electrodes for adsorbing gases. With this arrangement, it is possible to prevent pressure inside the capacitor from being elevated by gases produced in the capacitor, thereby enhancing the reliability of the capacitor.
    Type: Grant
    Filed: July 30, 1997
    Date of Patent: July 14, 1998
    Assignee: NEC Corporation
    Inventors: Munekazu Aoki, Masako Inagawa, Keitaro Katsu
  • Patent number: 5253148
    Abstract: The electric double layer capacitor is designed such that a pair of electrode plates each having a lead terminal portion are positioned on upper and lower faces of an electric double layer capacitor element, the resulting assembly is resin-molded with a heat-resistant resin while applying a desired pressure to the assembly through the upper and lower electrode plates and the lead terminal portions are formed into shapes having L-shaped sections. This structure makes it possible to easily provide chip type electric double layer capacitors capable of being surface-mounted.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: October 12, 1993
    Assignee: NEC Corporation
    Inventor: Keitaro Katsu
  • Patent number: 5093762
    Abstract: The components of the electrical capacitor according to the present invention consist only of unit cells, terminal plates and a molded portion, and operations such as caulking, etc. are not required so that production of the capacitor can be easily performed, by arranging and pressing electrode plates having terminals at the top and the bottom of the stacked unit cells of an electric double-layer capacitor in the stacked direction thereof, and applying molding process with resin, as it is.
    Type: Grant
    Filed: March 15, 1991
    Date of Patent: March 3, 1992
    Assignee: NEC Corporation
    Inventors: Kazuhiko Sato, Kazuhiko Kuwata, Hiroyasu Yamamoto, Keitaro Katsu