STORAGE DEVICE STATE DETECTION METHOD

• US 20150198675A1
• Filed: 03/26/2015
• Published: 07/16/2015
• Est. Priority Date: 11/12/2012
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: Alps Green Devices Co., Ltd. (Alps Alpine Co., Ltd.)
• Inventors: HEBIGUCHI, Hiroyuki
• Granted Patent: US 9,638,760 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

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.

Claims

1. A storage device state detection method in which an SOH or an SOC of a storage device is inferred from an internal impedance of a storage device, the method comprising:

measuring an internal resistance of the storage device by using a signal with a first frequency at which the internal impedance of the storage device is reduced as a temperature is raised, and calculating an initial SOH or an initial SOC of the storage device from a measured value of the internal resistance;

measuring the internal impedance of the storage device by using a signal with a second frequency at which the internal impedance of the storage device is increased as a temperature is raised, and calculating an internal temperature of the storage device from a measured impedance value of the internal impedance; and

inferring the SOH or the SOC by using a calculated value of the internal temperature to correct the initial SOH or the initial SOC.

4. The storage device state detection method according to claim 1, wherein when the SOH is inferred, the SOC is substantially the same in each measurement of the internal resistance.

5. The storage device state detection method according to claim 4, wherein when the SOH is inferred, the internal resistance is measured within a prescribed time after the storage device has been fully charged.

10. The storage device state detection method according to claim 1, wherein the internal resistance is measured before and after a large change of a current, and the internal resistance is obtained from measured values obtained before and after the large change.

13. The storage device state detection method according to claim 1, wherein:

the storage device is mounted in an automobile; and

the automobile is stopping during a measurement of the internal resistance.

16. The storage device state detection method according to claim 1, wherein:

a transient response signal induced by a pulse signal given to the storage is converted to a frequency component by a Fourier transform;

the internal impedance at the second frequency is calculated; and

a calculated value is used as the measured impedance value.

2. A storage device state detection method in which an SOH or an SOC of a storage device is inferred from an internal impedance of a storage device, the method comprising:

measuring an internal resistance of the storage device by using a 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 a measured value of the internal resistance;

measuring the internal impedance of the storage device by using a 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 an internal temperature of the storage device from a measured impedance value of the internal impedance; and

inferring the SOH or the SOC by using a calculated value of the internal temperature to correct the initial SOH or the initial SOC.

6. The storage device state detection method according to claim 2, wherein when the SOH is inferred, the SOC is substantially the same in each measurement of the internal resistance.

7. The storage device state detection method according to claim 6, wherein when the SOH is inferred, the internal resistance is measured within a prescribed time after the storage device has been fully charged.

11. The storage device state detection method according to claim 2, wherein the internal resistance is measured before and after a large change of a current, and the internal resistance is obtained from measured values before and after the large change.

14. The storage device state detection method according to claim 2, wherein:

the storage device is mounted in an automobile; and

the automobile is stopping during a measurement of the internal resistance.

17. The storage device state detection method according to claim 2, wherein:

a transient response signal induced by a pulse signal given to the storage is converted to a frequency component by a Fourier transform;

the internal impedance at the second frequency is calculated; and

a calculated value is used as the measured impedance value.

3. A storage device state detection method in which an SOH or an SOC of a storage device is inferred from an internal impedance of a storage device, the method comprising:

measuring an internal resistance of the storage device by using a signal with a first frequency of 1 kHz or lower, and calculating an initial SOH or an initial SOC of the storage device from a measured value of the internal resistance;

measuring the internal impedance of the storage device by using a signal with a second frequency of 10 kHz or higher, and calculating an internal temperature of the storage device from a measured value of the internal impedance; and

inferring the SOH or the SOC by using a calculated value of the internal temperature to correct the initial SOH or the initial SOC.

8. The storage device state detection method according to claim 3, wherein when the SOH is inferred, the SOC is substantially the same in each measurement of the internal resistance.

9. The storage device state detection method according to claim 8, wherein when the SOH is inferred, the internal resistance is measured within a prescribed time after the storage device has been fully charged.

12. The storage device state detection method according to claim 3, wherein the internal resistance is measured before and after a large change of a current, and the internal resistance is obtained from measured values obtained before and after the large change.

15. The storage device state detection method according to claim 3, wherein:

the storage device is mounted in an automobile; and

the automobile is stopping during a measurement of the internal resistance.

18. The storage device state detection method according to claim 3, wherein:

a transient response signal induced by a pulse signal given to the storage is converted to a frequency component by a Fourier transform;

the internal impedance at the second frequency is calculated; and

a calculated value is used as the measured impedance value of the internal impedance.