METHOD AND APPARATUS FOR DETERMINING DETERIORATION OF SECONDARY BATTERY, AND POWER SUPPLY SYSTEM THEREWITH
First Claim
1. A method for determining SOH of a secondary battery according to an internal impedance or an internal resistance of the secondary battery supplying power to a load, comprising:
- preparing in advance a specified temperature characteristic function which contains at least one exponential terms and one adjustment parameter and expresses a temperature dependency of the internal impedance or the internal resistance;
calculating the internal impedance or the internal resistance based on a measured current value or a measured voltage value at the time when the secondary battery is charged or discharged with a specified current;
determining a value of the adjustment parameter by substituting the measured temperature at the time when the secondary battery is charged or discharged with the specified current and the calculated internal impedance or the internal resistance to the temperature characteristic function;
calculating a reference internal impedance or a reference internal resistance by substituting the determined adjustment parameter value and a specified reference temperature into the temperature characteristic function; and
determining the SOH of the secondary battery based on the calculated reference internal impedance or the calculated reference internal resistance.
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Abstract
A method for detecting SOC and SOH of a storage battery includes: calculating an SOC value of the storage battery with use of an SOC calculation unit based on a measured voltage value or a measured current value of the storage battery and calculating an SOH value of the storage battery with use of an SOH calculation unit based on the SOC value; further calculating a new SOC value with use of the SOC calculation unit based on the SOH value and calculating a new SOH value with use of the SOH calculation unit based on the new SOC value, these further calculations of SOC value and SOH value being repeated a prescribed n times of at least one so as to obtain an nth calculated SOC value and an nth calculated SOH value; outputting the nth calculated SOH value as an SOH output value and outputting the nth calculated SOH value as an SOC output value; and storing the SOH output value into a memory.
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Citations
13 Claims
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1. A method for determining SOH of a secondary battery according to an internal impedance or an internal resistance of the secondary battery supplying power to a load, comprising:
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preparing in advance a specified temperature characteristic function which contains at least one exponential terms and one adjustment parameter and expresses a temperature dependency of the internal impedance or the internal resistance; calculating the internal impedance or the internal resistance based on a measured current value or a measured voltage value at the time when the secondary battery is charged or discharged with a specified current; determining a value of the adjustment parameter by substituting the measured temperature at the time when the secondary battery is charged or discharged with the specified current and the calculated internal impedance or the internal resistance to the temperature characteristic function; calculating a reference internal impedance or a reference internal resistance by substituting the determined adjustment parameter value and a specified reference temperature into the temperature characteristic function; and determining the SOH of the secondary battery based on the calculated reference internal impedance or the calculated reference internal resistance. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for determining an SOH of a secondary battery based on an internal impedance or an internal resistance of the secondary battery supplying power to a load, comprising:
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a charging circuit for charging the secondary battery with a specified current; a discharging circuit for discharging the secondary battery with a specified current; a current sensor for measuring a current of the secondary battery; a voltage sensor for measuring a voltage of the secondary battery; a temperature sensor for measuring a temperature of the secondary battery; and a control unit configured to;
(i) receive a measured current value, a measured voltage value, and a measured temperature value from the current sensor, the voltage sensor, and the temperature sensor, respectively, at the time when the secondary battery is charged or discharged with the specified current by the charging circuit or the discharging circuit;
(ii) calculate the internal impedance or the internal resistance based on the measured current value and the measured voltage value;
(iii) determine a value of a adjustment parameter by substituting the calculated internal impedance or the calculated internal resistance and the measured temperature into a temperature characteristic function which contains at least one exponential terms and one adjustment parameter and expresses a temperature dependency of the internal impedance or the internal resistance;
(iv) calculate a reference internal impedance or a reference internal resistance by substituting the decided adjustment parameter value and a specified reference temperature into the temperature characteristic function; and
(v) determine an SOH of the secondary battery based on the calculated reference internal impedance or the calculated reference internal resistance. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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Specification