Patents by Inventor Toshihisa Tamai

Toshihisa Tamai 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: 6447957
    Abstract: A collector for a secondary battery includes a metal foil having throughholes shaped or arranged to achieve an increased hole area ratio to improve an active material's adhesion thereto. A throughhole in the metal foil has a largest dimension of at least 1.55 mm, and the foil has a hole area ratio of at least 40%, and a thickness of at least 5 &mgr;m and at most 200 &mgr;m. The throughhole has a peripheral shape including two substantially straight sides that extend along lines intersecting with each other on their respective extensions to form an acute angle at a corner of the throughhole. To form the metal foil, a resist film with a predetermined pattern is arranged on a solid foil, and is used as a mask to etch the foil to provide the plurality of throughholes penetrating the foil.
    Type: Grant
    Filed: April 5, 2000
    Date of Patent: September 10, 2002
    Assignee: Toyo Aluminum Kabushiki Kaisha
    Inventors: Hiroyuki Sakamoto, Hiroshi Tada, Toshihisa Tamai