Patents by Inventor Hisafumi Asai

Hisafumi Asai 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: 8909490
    Abstract: An object of the present invention is to provide a battery state estimation device and a battery state estimation method which identify parameter of a secondary battery with high accuracy. A current and a terminal voltage of secondary battery are detected, then by using the current measured value and terminal voltage measured value thus detected, the terminal voltage of secondary battery based on predetermined battery model is estimated, and the parameter of the secondary battery is identified such that a difference between terminal voltage measured value and voltage estimated value is converged to zero. In the identifying of parameter of secondary battery, the terminal voltage measured value and terminal voltage estimated value are subjected to filter treatment by low pass filter having a common high frequency breaking characteristic and the terminal voltage measured value and terminal voltage estimated value subjected to the filter treatment are used.
    Type: Grant
    Filed: February 18, 2011
    Date of Patent: December 9, 2014
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Shiho Umeki, Hisafumi Asai, Hideo Nakamura, Kazuhiko Tazoe, Satoshi Segawa
  • Publication number: 20120316812
    Abstract: An object of the present invention is to provide a battery state estimation device and a battery state estimation method which identify parameter of a secondary battery with high accuracy. A current and a terminal voltage of secondary battery are detected, then by using the current measured value and terminal voltage measured value thus detected, the terminal voltage of secondary battery based on predetermined battery model is estimated, and the parameter of the secondary battery is identified such that a difference between terminal voltage measured value and voltage estimated value is converged to zero. In the identifying of parameter of secondary battery, the terminal voltage measured value and terminal voltage estimated value are subjected to filter treatment by low pass filter having a common high frequency breaking characteristic and the terminal voltage measured value and terminal voltage estimated value subjected to the filter treatment are used.
    Type: Application
    Filed: February 18, 2011
    Publication date: December 13, 2012
    Inventors: Shiho Umeki, Hisafumi Asai, Hideo Nakamura, Kazuhiko Tazoe, Satoshi Segawa
  • Patent number: 7564221
    Abstract: An inputtable/outputtable power estimating device and method that can correctly estimate maximum inputtable and/or outputtable power of a secondary battery that can continue for a prescribed period of time. When the secondary battery is continuously charged or discharged for a prescribed period of time, the estimated value of a maximum possible charge and/or discharge current is estimated such that the terminal voltage of the secondary battery reaches a predetermined upper limit voltage or lower limit voltage. The inputtable and/or outputtable power is estimated as the power that can be used to charge the secondary battery or be discharged from it on the basis of the estimated maximum possible current(s) and the respective upper limit voltage or lower limit voltage.
    Type: Grant
    Filed: November 28, 2006
    Date of Patent: July 21, 2009
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Hisafumi Asai, Hideaki Yonezawa, Hideo Nakamura
  • Patent number: 7352156
    Abstract: A state-of-charge (SOC) estimating device and method for a secondary battery that estimates the SOC of the battery with high precision when variation takes place in the parameters of the battery model, even if the input current is constant. A first SOC estimating part estimates the open-circuit voltage by estimating the battery parameters en bloc using an adaptive digital filter computing treatment from the measurement values of the current and the terminal voltage and computes a first estimated SOC of the secondary battery from the open-circuit voltage and a predetermined relationship between the open-circuit voltage and the SOC. A second SOC estimating part computes a second estimated SOC by means of current-integration. State-of-charge estimated value-selecting part selects the second SOC value as when the current is constant and otherwise selects the first SOC value.
    Type: Grant
    Filed: July 16, 2006
    Date of Patent: April 1, 2008
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Hiroyuki Ashizawa, Hideo Nakamura, Hisafumi Asai
  • Publication number: 20070145953
    Abstract: An inputtable/outputtable power estimating device and method that can correctly estimate maximum inputtable and/or outputtable power of a secondary battery that can continue for a prescribed period of time. When the secondary battery is continuously charged or discharged for a prescribed period of time, the estimated value of a maximum possible charge and/or discharge current is estimated such that the terminal voltage of the secondary battery reaches a predetermined upper limit voltage or lower limit voltage. The inputtable and/or outputtable power is estimated as the power that can be used to charge the secondary battery or be discharged from it on the basis of the estimated maximum possible current(s) and the respective upper limit voltage or lower limit voltage.
    Type: Application
    Filed: November 28, 2006
    Publication date: June 28, 2007
    Applicant: Nissan Motor Co., Ltd.
    Inventors: Hisafumi Asai, Hideaki Yonezawa, Hideo Nakamura
  • Publication number: 20070029973
    Abstract: A state-of-charge (SOC) estimating device and method for a secondary battery that estimates the SOC of the battery with high precision when variation takes place in the parameters of the battery model, even if the input current is constant. A first SOC estimating part estimates the open-circuit voltage by estimating the battery parameters en bloc using an adaptive digital filter computing treatment from the measurement values of the current and the terminal voltage and computes a first estimated SOC of the secondary battery from the open-circuit voltage and a predetermined relationship between the open-circuit voltage and the SOC. A second SOC estimating part computes a second estimated SOC by means of current-integration. State-of-charge estimated value-selecting part selects the second SOC value as when the current is constant and otherwise selects the first SOC value.
    Type: Application
    Filed: July 16, 2006
    Publication date: February 8, 2007
    Applicant: Nissan Motor Co., Ltd.
    Inventors: Hiroyuki Ashizawa, Hideo Nakamura, Hisafumi Asai