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1. WO2011004249 - SECONDARY BATTERY TEMPERATURE-ESTIMATING APPARATUS AND METHOD

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS:

1. A secondary battery temperature-estimating apparatus for estimating a temperature of a secondary battery, comprising:

a ripple generating section that is connected to the secondary battery and adapted to cause a ripple current at a predetermined frequency to flow in the secondary battery; an electric current detecting section that detects an electric current charging or discharging the secondary battery;

a voltage detecting section that detects a voltage of the secondary battery;

an impedance estimating section that estimates an impedance of the secondary battery based on the electric current detected by the electric current detecting section and the voltage detected by the voltage detecting section when the ripple generating section causes the ripple current to flow in the secondary battery; and

a temperature estimating section that estimates the temperature of the secondary battery based on the impedance estimated by the impedance estimating section with the use of a relation, obtained in advance, between the temperature of the secondary battery and the impedance of the secondary battery.

2. The secondary battery temperature-estimating apparatus according to claim 1, wherein:

the impedance estimating section estimates an alternating current impedance of the secondary battery at the predetermined frequency based on the electric current detected by the electric current detecting section and the voltage detected by the voltage detecting section when the ripple generating section causes the ripple current to flow in the secondary battery; and

the temperature estimating section estimates the temperature of the secondary battery based on the alternating current impedance estimated by the impedance estimating section with the use of a relation, obtained in advance, between the temperature of the secondary battery and the alternating current impedance of the secondary battery at the predetermined frequency.

3. The secondary battery temperature-estimating apparatus according to claim 1, wherein the impedance estimating section includes: an offset electric current calculating section that calculates an offset electric current represented by an average value of the detected electric current, based on the electric current detected by the electric current detecting section when the ripple generating section causes the ripple current to flow in the secondary battery; an offset voltage calculating section that calculates an offset voltage that is a difference between an open-circuit voltage of the secondary battery and an average value of the detected voltage, based on the voltage detected by the voltage detecting section when the ripple generating section causes the ripple current to flow in the secondary battery; and a direct-current resistance estimating section that estimates a direct current resistance of the secondary battery based on the offset electric current and the offset voltage, and

wherein the temperature estimating section estimates the temperature of the secondary battery based on the direct current resistance estimated by the direct-current resistance estimating section with the use of a relation, obtained in advance, between the temperature of the secondary battery and the direct current resistance of the secondary battery.

4. The secondary battery temperature-estimating apparatus according to any one of claims 1 to 3, wherein each of the electric current detecting section and the voltage detecting section includes a peak value acquiring section that acquires a peak value of the detected value.

5. A secondary battery temperature-estimating apparatus for estimating a temperature of a secondary battery, comprising:

a ripple generating section that is connected to the secondary battery and adapted to cause a ripple current at a predetermined frequency to flow in the secondary battery;

o

an electric current detecting section that detects an electric current charging or discharging the secondary battery;

a state of charge (SOC) estimating section that estimates an SOC of the secondary battery based on the electric current detected by the electric current detecting section; a loss estimating section that estimates an energy loss of the secondary battery based on the SOC estimated when the ripple generating section causes the ripple current to flow in the secondary battery; and

a temperature estimating section that estimates an amount of change in the temperature of the secondary battery based on the energy loss of the secondary battery estimated by the loss estimating section and estimates the temperature of the secondary battery based on the estimated amount of change in the temperature.

6. The secondary battery temperature-estimating apparatus according to claim 5, wherein

the SOC estimating section includes: an offset electric current calculating section that calculates an offset electric current represented by an average value of the detected electric current, based on the electric current detected by the electric current detecting section when the ripple generating section causes the ripple current to flow in the secondary battery; a discharge amount estimating section that estimates an amount of discharge from the secondary battery obtained by integrating the offset electric current; and a change amount estimating section that estimates an amount of change in the SOC of the secondary battery by dividing the amount of discharge from the secondary battery estimated by the discharge amount estimating section by a capacity of the secondary battery.

7. The secondary battery temperature-estimating apparatus according to claim 5 or 6, wherein the electric current detecting section includes a peak value acquiring section that acquires a peak value of the detected value.

8. A secondary battery temperature-estimating method of estimating a temperature of a secondary battery, comprising:

causing a ripple current at a predetermined frequency to flow in the secondary battery; detecting an electric current charging or discharging the secondary battery;

detecting a voltage of the secondary battery;

estimating an impedance of the secondary battery based on the electric current and the voltage detected when the ripple current is caused to flow in the secondary battery; and estimating the temperature of the secondary battery based on the estimated impedance with the use of a relation, obtained in advance, between the temperature of the secondary battery and the impedance of the secondary battery.

9. The secondary battery temperature-estimating method according to claim 8, wherein:

in estimating the impedance, an alternating current impedance of the secondary battery at the predetermined frequency is estimated based on the electric current and the voltage detected when the ripple current is caused to flow in the secondary battery; and

in estimating the temperature, the temperature of the secondary battery is estimated based on the estimated alternating current impedance with the use of a relation, obtained in advance, between the temperature of the secondary battery and the alternating current impedance of the secondary battery at the predetermined frequency.

10. The secondary battery temperature-estimating method according to claim 8, wherein estimating the impedance includes: calculating an offset electric current represented by an average value of the detected electric current, based on the electric current detected when the ripple current is caused to flow in the secondary battery; calculating an offset voltage that is a difference between an open-circuit voltage of the secondary battery and an average value of the detected voltage, based on the voltage detected when the ripple current is caused to flow in the secondary battery; and estimating a direct current resistance of the secondary battery based on the offset electric current and the offset voltage, and

wherein in estimating the temperature, the temperature of the secondary battery is estimated based on the estimated direct current resistance with the use of a relation, obtained in advance, between the temperature of the secondary battery and the direct current resistance of the secondary battery.

11. A secondary battery temperature-estimating method of estimating a temperature of a secondary battery, comprising:

causing a ripple current at a predetermined frequency to flow in the secondary battery; detecting an electric current charging or discharging the secondary battery;

estimating a state of charge (SOC) of the secondary battery based on the detected electric current;

estimating an energy loss of the secondary battery based on the SOC estimated when the ripple current is caused to flow in the secondary battery; and

estimating an amount of change in the temperature of the secondary battery based on the estimated energy loss of the secondary battery and estimating the temperature of the secondary battery based on the estimated amount of change in the temperature.

12. The secondary battery temperature-estimating method according to claim 11, wherein

the estimating the SOC includes: calculating an offset electric current represented by an average value of the detected electric current, based on the electric current detected when the ripple current is caused to flow in the secondary battery; estimating an amount of discharge from the secondary battery obtained by integrating the offset electric current; and estimating an amount of change in the SOC of the secondary battery by dividing the estimated amount of discharge from the secondary battery by a capacity of the secondary battery.