Apparatus for detecting charged state of secondary battery

• US 20070090805A1
• Filed: 10/26/2006
• Published: 04/26/2007
• Est. Priority Date: 10/26/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Soken, Inc.
• Original Assignee: DENSO Corporation, Nippon Soken, Inc.
• Inventors: Ueda, Kenji, Kato, Akira, Tanaka, Katsunori, Sakai, Shoji, Mizuno, Satoru, Sou, Masahiro, Sada, Takeshi, Hashikawa, Atsushi
• Granted Patent: US 7,679,328 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A charged state detecting apparatus for a secondary battery is provided, which can suppress deterioration in the accuracy of detecting a charged state, such as an SOC, the deterioration being caused by variation of a polarization state of a battery. The charged state detecting apparatus stabilizes an amount of polarization of the battery, stops power generation upon confirmation of the stabilization of the polarization amount, and sufficiently alters the current of the battery to sample a required number of data pairs of voltage and current of the battery. Using these data pairs, the charged state detecting apparatus detects a charged state, such as the SOC, of the battery.

Claims

1. An apparatus for detecting a charged state of a battery being mounted on a vehicle, the apparatus comprising:

a data acquiring device configured to acquire a plurality of pairs of data consisting of current and voltage of the battery; and

a charged-state detecting device configured to detect the charged state of the battery based on the plurality of pairs of data acquired by the data acquisition device after recognizing stabilization of a polarized state of the battery.

2. The apparatus according to claim 1, wherein the charged-state detecting device comprises

a stabilizing device configured to stabilize an amount of polarization of the battery at a predetermined level;

and

a calculating device configured to calculate the charged state of the battery by using the pairs of data acquired by the data acquiring device immediately after it is confirmed that the polarized state of the battery is stabilized by the stabilizing device.

3. The apparatus according to claim 2, wherein the stabilizing device is configured to charge and discharge the battery over a specified period of time.

4. The apparatus according to claim 2, wherein the stabilizing device is configured to make the amount of polarization of the battery converge at a predetermined amount, the amount of polarization of the battery being calculated based on charge and discharge currents acquired when the battery Is subjected to charge and discharge at a fixed voltage.

5. The apparatus according to claim 2, wherein the calculating device is configured to acquire the pairs of data, by a necessary number of pairs of data, from the data acquiring device by changing the current of the battery after the polarized state of the battery is stabilized by the stabilizing device and calculate the charged state of the battery based on the acquired necessary number of pairs of data.

6. The apparatus according to claim 2, wherein the calculating device is configured to calculate a pseudo open-circuit voltage of the battery based on the pairs of data acquired in a state where the polarized state of the battery Is stabilized and an Internal resistance of the battery calculated at a latest sampling time and to calculate an SOC (state of charge) based on the pseudo open-circuit voltage.

7. The apparatus according to claim 2, wherein the calculating device comprises

a predetermined input/output table showing relationships between input parameters defining state amounts of a plurality of types of reference batteries and output parameters defining charged states of the reference batteries,

means for acquiring a necessary number of pairs of data, as the pairs of data, of the battery by forcibly changing current of the battery after the polarized state of the battery is stabilized by the stabilizing device, and

means for calculating the charged state of the battery by calculating a state amount of the battery based on the acquired necessary number of pairs of data and inputting the resultant state amount of the battery to the input/output table.

8. The apparatus according to claim 2, wherein the charged-state detecting device further comprises control means for controlling the stabilizing device and the calculating device such that the polarized state of the battery is stabilized immediately after start of an engine being mounted on the vehicle and, immediately after the stabilization of the polarized state, the charged state of the battery Is detected.

9. The apparatus according to claim 2, wherein the charged-state detecting device further comprises control means for controlling the stabilizing device and the calculating device such that the polarized state of the battery Is stabilized at intervals during an operation of an engine being mounted on the vehicle and, immediately after the stabilization of the polarized state, the charged state of the battery is detected.

10. The apparatus according to claim 2, wherein

the battery is connected to a generator being mounted on a vehicle so as to receive power to be charged from the generator and

the charged-state detecting device further comprises command means for commanding the generator to raise the power to be charged only when the charged state of the battery detected immediately after the stabilization of the polarized state of the battery is less than a minimum reference value.

11. The apparatus according to claim 1, wherein the charged-state detecting device comprises

a determining device configured to determine whether or not the polarization of the battery substantially disappears;

an acquiring device configured to acquire a necessary number of pairs of data of the battery through the data acquiring device by changing a current state of the battery immediately after the determining device determines that the polarization of the battery substantially disappears; and

a charged-state calculating device configured to calculate the charged state of the battery based on the necessary number of pairs of data acquired by the acquiring device.

12. The apparatus according to claim 11, wherein the determining device is configured to determine that the polarization of the batter has substantially disappeared, provided that a state wherein a voltage of the battery is substantially equal to a reference value and a charge/discharge current is equal to or less than a reference value lasts more than a predetermined period of time.

13. The apparatus according to claim 11, wherein

the determining device is configured to determine that the polarization of the battery has substantially disappeared, provided that a predetermined period of time has elapsed since a last turn-off operation of ignition of the vehicle and

the charged-state calculating device is configured to calculate the charged state of the battery based on pairs of data acquired when an engine being mounted on the vehicle Is started.

14. The apparatus according to claim 3, wherein the charged-state detecting device further comprises control means for controlling the stabilizing device and the calculating device such that the polarized state of the battery is stabilized immediately after start of an engine being mounted on the vehicle and, immediately after the stabilization of the polarized state, the charged state of the battery is detected.

15. The apparatus according to claim 3, wherein the charged-state detecting device further comprises control means for controlling the stabilizing device and the calculating device such that the polarized state of the battery Is stabilized at intervals during an operation of an engine being mounted on the vehicle and, immediately after the stabilization of the polarized state, the charged state of the battery is detected.

16. The apparatus according to claim 3, wherein

the battery is connected to a generator being mounted on a vehicle so as to receive power to be charged from the generator and

the charged-state detecting device further comprises command means for commanding the generator to raise the power to be charged only when the charged state of the battery detected immediately after the stabilization of the polarized state of the battery Is less than a minimum reference value.

17. The apparatus according to claim 4, wherein the charged-state detecting device further comprises control means for controlling the stabilizing device and the calculating device such that the polarized state of the battery Is stabilized immediately after start of an engine being mounted on the vehicle and, immediately after the stabilization of the polarized state, the charged state of the battery is detected.

18. The apparatus according to claim 4, wherein the charged-state detecting device further comprises control means for controlling the stabilizing device and the calculating device such that the polarized state of the battery is stabilized at intervals during an operation of an engine being mounted on the vehicle and, immediately after the stabilization of the polarized state, the charged state of the battery is detected.

19. The apparatus according to claim 4, wherein

the battery is connected to a generator being mounted on a vehicle so as to receive power to be charged from the generator and

the charged-state detecting device further comprises command means for commanding the generator to raise the power to be charged only when the charged state of the battery detected immediately after the stabilization of the polarized state of the battery is less than a minimum reference value.