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Device and method for estimating remaining battery capacity

  • US 9,977,087 B2
  • Filed: 02/05/2015
  • Issued: 05/22/2018
  • Est. Priority Date: 04/23/2014
  • Status: Active Grant
First Claim
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1. A remaining battery capacity estimating device for estimating a remaining battery capacity from inter-terminal voltage of a battery and current passed through the battery, comprising:

  • a current measuring unit that measures the current;

    a voltage measuring unit that measures the inter-terminal voltage;

    a first remaining capacity storage that stores a first remaining battery capacity as a remaining battery capacity correlated with open-circuit voltage of the battery;

    a second remaining capacity storage that stores a second remaining battery capacity produced by subtracting the first remaining battery capacity from the remaining battery capacity that increases and decreases by the current;

    a current calculator that calculates remaining capacity difference current between the first remaining battery capacity and the second remaining battery capacity;

    a first remaining capacity estimator that estimates the first remaining battery capacity on the basis of a value obtained by removing the remaining capacity difference current from the current and the inter-terminal voltage and has the estimate stored in the first remaining capacity storage;

    a second remaining capacity calculator that calculates the second remaining battery capacity by adding up the remaining capacity difference current and has the result stored in the second remaining capacity storage; and

    an adder that obtains the remaining battery capacity by adding the first remaining battery capacity and the second remaining battery capacity,wherein the remaining capacity difference current of the current calculator being, when the battery is charged, a current value that allows the second remaining battery capacity to be smaller than the first remaining battery capacity by a quantity corresponding to a first potential difference as a potential difference during battery charging, andthe remaining capacity difference current of the current calculator being, when the battery is discharged, a current value that allows the first remaining battery capacity to be smaller than the second remaining battery capacity by a quantity corresponding to a second potential difference as a potential difference during battery discharging.

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