Method for detecting state of secondary battery and device for detecting state of second battery
First Claim
1. A method for detecting the state of a secondary battery, comprising:
- (a) a step of acquiring a plurality of data sets associating a current flowing through the secondary battery with a terminal voltage of the secondary battery corresponding to that current;
(b) a step of making the plurality of data sets valid when specific selection conditions are satisfied;
(c) a step of performing statistical processing with respect to the plurality of valid data sets during charging and discharging, and calculating a value of internal resistance during charging and discharging of the secondary battery from the slope of a linear approximation obtained by the statistical processing;
(d) a step of performing statistical processing with respect to the plurality of valid data sets during charging, and calculating a value of internal resistance during charging of the secondary battery from the slope of a linear approximation obtained by the statistical processing; and
(e) a step of calculating a value of internal resistance of the secondary battery based on the value of internal resistance during charging and discharging and the value of internal resistance during charging.
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Accused Products
Abstract
Based on a plurality of valid data sets from a data set selection portion, an internal-resistance-during-charging calculation portion calculates the value Rc of internal resistance during charging from the slope of a voltage-current linear approximation during charging, and an internal-resistance-during-charging-and-discharging calculation portion calculates the value Rcd of internal resistance during charging and discharging from the slope of a voltage-current linear approximation during charging and discharging. A judgment portion compares the absolute value ΔR of the difference between Rcd and Rc that has been calculated by a difference computation portion with a first predetermined value ΔRT1, and when ΔR≦ΔRT1 is satisfied, the judgment portion outputs Rcd or Rc, whichever is smaller, as the value of internal resistance of a secondary battery.
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Citations
10 Claims
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1. A method for detecting the state of a secondary battery, comprising:
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(a) a step of acquiring a plurality of data sets associating a current flowing through the secondary battery with a terminal voltage of the secondary battery corresponding to that current;
(b) a step of making the plurality of data sets valid when specific selection conditions are satisfied;
(c) a step of performing statistical processing with respect to the plurality of valid data sets during charging and discharging, and calculating a value of internal resistance during charging and discharging of the secondary battery from the slope of a linear approximation obtained by the statistical processing;
(d) a step of performing statistical processing with respect to the plurality of valid data sets during charging, and calculating a value of internal resistance during charging of the secondary battery from the slope of a linear approximation obtained by the statistical processing; and
(e) a step of calculating a value of internal resistance of the secondary battery based on the value of internal resistance during charging and discharging and the value of internal resistance during charging. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A device for detecting the state of a secondary battery, comprising:
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a current measurement portion that measures the current flowing through the secondary battery as current data;
a voltage measurement portion that measures the terminal voltage of the secondary battery as voltage data;
a data set selection portion that acquires a plurality of data sets comprising the current data from the current measurement portion and the voltage data from the voltage measurement portion that corresponds to the current data, and that outputs the plurality of data sets as valid data sets when specific selection conditions are satisfied;
an internal-resistance-during-charging-and-discharging calculation portion that performs statistical processing with respect to the plurality of valid data sets during charging and discharging, and calculating a value of internal resistance during charging and discharging of the secondary battery from the slope of a linear approximation obtained by the statistical processing;
an internal-resistance-during-charging calculation portion that performs statistical processing with respect to the plurality of valid data sets during charging, and calculating a value of internal resistance during charging of the secondary battery from the slope of a linear approximation obtained by the statistical processing;
a difference computation portion that calculates an absolute value of the difference between the value of internal resistance during charging and discharging and the value of internal resistance during charging, and that also outputs a signal indicating the magnitude correlation between the value of internal resistance during charging and discharging and the value of internal resistance during charging; and
a judgment portion that judges whether or not the absolute value of the difference from the difference computation portion is equal to or less than a first predetermined value, and that outputs the value of internal resistance during charging and discharging or the value of internal resistance during charging, whichever is smaller, as a value of internal resistance of the secondary battery when the absolute value of the difference is equal to or less than the first predetermined value. - View Dependent Claims (8, 9, 10)
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Specification