Storage device state detection method
View Patent ↗In a storage device state detection method in which the SOH or SOC of the storage device is inferred from the internal impedance of the storage device: the internal resistance of the storage device is measured by using a signal with a first frequency at which the internal impedance is reduced as a temperature is raised, and the initial SOH or initial SOC of the storage device is calculated from the measured value of the internal resistance; the internal impedance is measured by using a signal with a second frequency at which the internal impedance is increased as a temperature is raised, and the internal temperature of the storage device is calculated from the measured value of the internal impedance; and the SOH or SOC is inferred by using the calculated value of the internal temperature to correct the initial SOH or initial SOC.
1. A method for detecting a state of a storage device in which an SOH (State of Health) or an SOC (State of Charge) of the storage device is estimated from an internal impedance thereof, the method comprising:
measuring an internal resistance of the storage device using a first signal with a first frequency at which the internal impedance of the storage device decreases as a temperature rises, and calculating an initial SOH or an initial SOC of the storage device from the measured internal resistance;
measuring the internal impedance of the storage device using a second signal with a second frequency at which the internal impedance of the storage device increases as the temperature rises, and calculating a value of an internal temperature of the storage device from the measured internal impedance; and
estimating the SOH or the SOC using the calculated value of the internal temperature to correct the initial SOH or the initial SOC.
2. The method according to claim 1 , wherein when the SOH is estimated, the SOC is substantially the same in each measurement of the internal resistance.
3. The method according to claim 2 , wherein the SOH is estimated by measuring, the internal resistance is within a prescribed time period after the storage device has been fully charged.
4. The method according to claim 1 , wherein the internal resistance is measured before and after a large change occurred in a current, and a value of the internal resistance is obtained from the measured internal resistance before and after the large change.
5. The method according to claim 1 , wherein:
the storage device is mounted in an automobile; and
the automobile is stopped during the measurement of the internal resistance.
6. The method according to claim 1 , wherein:
a value of the measured internal impedance at the second frequency is calculated by converting a transient response signal induced by a pulse signal given to the storage device into a frequency component by a Fourier transform.
7. A method for detecting a state of a storage device in which an SOH (State of Health) or an SOC (State of Charge) of the storage device is estimated from an internal impedance thereof, the method comprising:
measuring an internal resistance of the storage device using a first signal with a first frequency at which a capacitance component of the internal impedance of the storage device becomes more dominant than an inductance component of the internal impedance, and calculating an initial SOH or an initial SOC of the storage device from the measured internal resistance;
measuring the internal impedance of the storage device using a second signal with a second frequency at which the inductance component of the internal impedance of the storage device becomes more dominant than the capacitance component of the internal impedance, and calculating a value of an internal temperature of the storage device from the measured internal impedance; and
estimating the SOH or the SOC using the calculated value of the internal temperature to correct the initial SOH or the initial SOC.
8. The method according to claim 7 , wherein when the SOH is estimated, the SOC is substantially the same in each measurement of the internal resistance.
9. The method according to claim 8 , wherein the SOH is estimated by measuring, the internal resistance within a prescribed time period after the storage device has been fully charged.
10. The method according to claim 7 , wherein the internal resistance is measured before and after a large change occurred in a current, and a value of the internal resistance is obtained from the measured internal resistance before and after the large change.
11. The method according to claim 7 , wherein:
the storage device is mounted in an automobile; and
the automobile is stopped during the measurement of the internal resistance.
12. The method according to claim 7 , wherein:
a value of the measured internal impedance at the second frequency is calculated by converting a transient response signal induced by a pulse signal given to the storage device into a frequency component by a Fourier transform.
13. A method for detecting a state of a storage device in which an SOH (State of Health) or an SOC (State of Charge) of the storage device is estimated from an internal impedance thereof, the method comprising:
measuring an internal resistance of the storage device using a first signal with a first frequency of 1 kHz or lower, and calculating an initial SOH or an initial SOC of the storage device from the measured internal resistance;
measuring the internal impedance of the storage device using a second signal with a second frequency of 10 kHz or higher, and calculating a value of an internal temperature of the storage device from the measured internal impedance; and
estimating the SOH or the SOC using the calculated value of the internal temperature to correct the initial SOH or the initial SOC.
14. The method according to claim 13 , wherein when the SOH is estimated, the SOC is substantially the same in each measurement of the internal resistance.
15. The method according to claim 14 , wherein the SOH is estimated by measuring, the internal resistance within a prescribed time period after the storage device has been fully charged.
16. The method according to claim 13 , wherein the internal resistance is measured before and after a large change occurred in a current, and a value of the internal resistance is obtained from the measured internal resistance before and after the large change.
17. The method according to claim 13 , wherein:
the storage device is mounted in an automobile; and
the automobile is stopped during the measurement of the internal resistance.
18. The method according to claim 13 , wherein:
a value of the measured internal impedance at the second frequency is calculated by converting a transient response signal induced by a pulse signal given to the storage device into a frequency component by a Fourier transform.