Patents by Inventor Keiichiro Okawa

Keiichiro Okawa 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).

  • Electric storage device
    Patent number: 9293937
    Abstract: An electric storage device includes an assembled battery including a plurality of electric cells connected in series; an assembled battery control unit that estimates internal resistances of the plurality of electric cells, or a magnitude relationship of the internal resistances of the plurality of electric cells; an assembled battery control unit that calculates such a discharge quantity that an SOC after the electric cells have been discharged becomes lower as the internal resistance of the electric cells, which is estimated by the assembled battery control unit, is larger, or as the magnitude relationship of the internal resistances of the electric cells is estimated to be larger by the assembled battery control unit, for each of the electric cells; and electric cell control units that discharge each of the plurality of electric cells on the basis of the discharge quantity calculated by the assembled battery control unit.
    Type: Grant
    Filed: April 18, 2011
    Date of Patent: March 22, 2016
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Youhei Kawahara, Ryouhei Nakao, Akihiko Kudo, Akihiko Emori, Keiichiro Okawa, Yoshinori Aoshima
  • ELECTRIC STORAGE DEVICE
    Publication number: 20140042973
    Abstract: An electric storage device includes an assembled battery including a plurality of electric cells connected in series; an assembled battery control unit that estimates internal resistances of the plurality of electric cells, or a magnitude relationship of the internal resistances of the plurality of electric cells; an assembled battery control unit that calculates such a discharge quantity that an SOC after the electric cells have been discharged becomes lower as the internal resistance of the electric cells, which is estimated by the assembled battery control unit, is larger, or as the magnitude relationship of the internal resistances of the electric cells is estimated to be larger by the assembled battery control unit, for each of the electric cells; and electric cell control units that discharge each of the plurality of electric cells on the basis of the discharge quantity calculated by the assembled battery control unit.
    Type: Application
    Filed: April 18, 2011
    Publication date: February 13, 2014
    Applicant: HITACHI VEHICLE ENERGY, LTD.
    Inventors: Youhei Kawahara, Ryouhei Nakao, Akihiko Kudo, Akihiko Emori, Keiichiro Okawa, Yoshinori Aoshima