Method and apparatus of correcting battery characteristic and of estimating residual capacity of battery

• US 6,160,380 A
• Filed: 10/22/1998
• Issued: 12/12/2000
• Est. Priority Date: 02/13/1997
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Tsuji, Tadashi, Origuchi, Masato, Sodeno, Tsuyoshi
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/177,112
• Time in Patent Office: 782 Days
• Field of Search: 320/132, 324/427, 340/636
• US Class Current: 320/132
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method and apparatus of estimating a residual energy of a battery for an electric vehicle. A battery characteristic is corrected on the basis of a temperature correction factor and a deterioration correction factor which are obtained on the basis of the condition of the battery. The deterioration correction factor includes an internal resistance deterioration correction factor indicative of a deterioration ratio of a battery internal resistance and a energy deterioration correction factor indicative of a deterioration ratio of a battery energy. The residual capacity is calculated on the basis of the corrected battery characteristic, a discharge current and a terminal voltage of the battery. Therefore, a residual energy meter accurately displays a residual energy of the battery.

Claims

1. A method for correcting battery characteristic comprising the steps of:

detecting a temperature of a battery;

calculating a temperature correction factor on the basis of the detected battery temperature;

detecting a discharge characteristic of the battery;

calculating a deterioration correction factor on the basis of the detected battery discharge characteristic, the deterioration correction factor being constituted by an internal resistance deterioration correction factor relating to the change of an internal resistance of the battery and a capacity deterioration correction factor relating to the change of a battery capacity; and

correcting a battery characteristic on the basis of the calculated battery temperature correction factor and the calculated deterioration correction factor.

2. A method as claimed in claim 1, wherein the internal resistance deterioration correction factor is calculated on the basis of a full charged power calculated from a discharge current and a terminal voltage of the battery in a full charged condition and a temperature-corrected power calculated from a temperature and the battery characteristic.

3. The method as claimed in claim 1, wherein a correlation between the internal resistance deterioration correction factor and the capacity deterioration correction factor is calculated on the basis of the change of the capacity of the battery and the deterioration of the output of the battery.

4. The method as claimed in claim 1, wherein the correction of the battery characteristic is executed on the basis of a calculated internal resistance change correction factor and a previously calculated internal resistance change correction factor.

5. The method as claimed in claim 4, wherein the battery characteristic is corrected by using the calculated internal resistance change correction factor and an average of plural-times calculated values of the internal resistance change correction factor previously calculated.

6. A battery characteristic correcting method used in estimating a residual energy of a battery on the basis of a battery characteristic corrected by the battery characteristic correcting method, a discharge current and a terminal voltage of the battery during discharging, said battery characteristic correcting method comprising the steps of:

detecting a temperature of the battery;

calculating a temperature correction factor on the basis of the detected battery temperature;

detecting a discharge characteristic of the battery;

calculating a deterioration correction factor on the basis of the detection battery discharge characteristic; and

correcting a battery characteristic on the basis of the calculated battery temperature correction factor and the calculated deterioration correction factor, wherein

the deterioration correction factor is constituted by an internal resistance deterioration correction factor relating to the change of an internal resistance of the battery and a capacity deterioration correction factor relating to the change of a battery capacity.

7. A method of estimating a residual energy of a battery comprising the steps of:

calculating a dischargeable amount and a discharge power amount of the battery from a corrected battery characteristic obtained by a battery characteristic correcting method; and

calculating the residual energy of the battery from the calculated dischargeable amount and the discharged power amount of the battery, wherein

the battery characteristic correcting method comprises the steps of detecting a temperature of a battery, calculating a temperature correction factor on the basis of the detected battery temperature, detecting a discharge characteristic of the battery, calculating a deterioration correction factor on the basis of the detected battery discharge characteristic, and correcting a battery characteristic on the basis of the calculated battery temperature correction factor and the calculated deterioration correction factor, wherein

the deterioration correction factor is constituted by an internal resistance deterioration correction factor relating to the change of an internal resistance of the battery and a capacity deterioration correction factor relating to the change of a battery capacity.

8. A method of estimating a residual energy of a battery comprising the steps of:

estimating the residual energy of the battery using the following equation;

(residual energy)=(battery dischargeable amount)-(battery discharged power amount), wherein

the battery dischargeable amount is a power amount which the battery discharges from a full capacity condition to a minimum power condition, and in the minimum power condition the battery can discharge a power for traveling an electric vehicle in a specified travel mode.

9. The method of estimating a residual energy of a battery comprising the steps of:

estimating the residual energy of the battery using the following equation;

space="preserve" listing-type="equation">(residual energy)=(battery dischargeable amount)-(battery discharged power amount),

wherein

the dischargeable amount is set at a value smaller than a power amount which the battery discharges from a full capacity condition to a minimum power condition, and in the minimum power condition the battery can discharge a power for traveling an electric vehicle in a specified travel mode.

10. An apparatus of correcting battery characteristic comprising:

a temperature detecting section detecting a temperature of a battery;

a temperature correction factor calculating section calculating a temperature correction factor on the basis of the detected battery temperature;

a deterioration detecting section detecting a discharge characteristic of the battery, the deterioration correcting factor being constituted by an internal resistance deterioration correction factor relating to the change of an internal resistance of the battery and a capacity deterioration correction factor relating to the change of a battery capacity;

a deterioration correction factor calculating section calculating a deterioration correction factor on the basis of the detected battery discharge characteristic; and

a battery characteristic correcting section correcting the battery characteristic on the basis of the calculated battery temperature correction factor and the calculated deterioration correction factor.

11. The apparatus as claimed in claim 10, wherein the internal resistance deterioration correction factor is calculated on the basis of a full charged power calculated from a discharge current and a terminal voltage of the battery in a full charged condition and a temperature corrected power calculated from a temperature and the battery characteristic.

12. The apparatus as claimed in claim 10, wherein a correlation between the internal resistance deterioration correction factor and the capacity deterioration correction factor is calculated on the basis of the change of the capacity of the battery and the deterioration of the output of the battery.

13. The apparatus as claimed in claim 10, wherein the correction of the battery characteristic is executed on the basis of a calculated internal resistance change correction factor and a previously calculated internal resistance change correction factor.

14. An apparatus as claimed in claim 13, wherein the battery characteristic is corrected by using the calculated internal resistance change correction factor and an average of plural-times calculated values of the internal resistance change correction factor previously calculated.

15. A battery characteristic correcting apparatus used in estimating a residual energy of a battery on the basis of a battery characteristic corrected by the battery characteristic correcting apparatus, a discharge current and a terminal voltage of the battery during discharging, the battery characteristic correcting apparatus comprising:

a temperature detecting section detecting a temperature of the battery;

a temperature correction factor calculating section calculating a temperature correction factor on the basis of the detected battery temperature;

a deterioration detecting section detecting a discharge characteristic of the battery;

a deterioration correction factor calculating section calculating a deterioration correction factor on the basis of the detected battery discharge characteristic; and

a battery characteristic correcting section correcting the battery characteristic on the basis of the calculated battery temperature correction factor and the calculated deterioration correction factor, wherein

the deterioration correction factor is constituted by an internal resistance deterioration correction factor relating to the change of an internal resistance of the battery and a capacity deterioration correction factor relating to the change of a battery capacity.

16. An apparatus of estimating a residual energy of a battery comprising:

a battery characteristic calculating section calculating a dischargeable amount and a discharged power amount of the battery from the corrected battery characteristic obtained by a battery characteristic correcting apparatus;

a residual energy calculating section calculating the residual energy of the battery from the calculated dischargeable amount and the discharged power amount of the battery; and

a display section displaying the residual energy calculated by said residual energy calculating section, wherein

the battery characteristic correcting apparatus comprises

a temperature detecting section detecting a temperature of the battery,

a temperature correction factor calculating section calculating a temperature correction factor on the basis of the detected battery temperature,

a deterioration detecting section detecting a discharge characteristic of the battery,

a deterioration correction factor calculating section calculating a deterioration correction factor on the basis of the detected battery discharge characteristic, and

a battery characteristic correcting section correcting the battery characteristic on the basis of the calculated battery temperature correction factor and the calculated deterioration correction factor, and

the deterioration correction factor is constituted by an internal resistance deterioration correction factor relating to the change of an internal resistance of the battery and a capacity deterioration correction factor relating to the change of a batter capacity.

17. An apparatus of estimating a residual energy of a battery of an electric vehicle comprising:

a residual energy estimating section estimating a residual energy of the battery using the following equation;

space="preserve" listing-type="equation">(residual energy)=(battery dischargeable amount)-(battery discharged power amount),

wherein the dischargeable amount is a power amount which is discharged by the battery from a full capacity condition to a minimum power condition, and in the minimum power condition the battery can discharge a power for traveling an electric vehicle in a specified travel mode; and

a displaying section displaying the residual energy estimated by said residual energy estimating section.

18. An apparatus of estimating a residual energy of a battery comprising:

a residual energy estimating section estimating a residual energy of the battery using the following equation;

space="preserve" listing-type="equation">(residual energy)=(battery dischargeable amount)-(battery discharged power amount),

wherein the dischargeable amount is set at a value smaller than a power amount which the battery discharges from a full capacity condition to a minimum power condition, and in the minimum power condition the battery can discharge a power for traveling an electric vehicle in a specified travel mode; and

a display section displaying the residual energy estimated by said residual energy estimating section.

19. A method for correcting a battery characteristic comprising the steps of:

calculating a temperature correction factor representative of a degree of a temperature dependency of the battery characteristic;

calculating an internal resistance deterioration correction factor representative of a ratio between an internal resistance of a new battery and that of a deteriorated battery;

calculating a capacity deterioration correction factor representative of a ratio between a dischargeable power amount of the new battery and that of the deteriorated battery; and

correcting the battery characteristic on the basis of the temperature correction factor, the internal resistance deterioration correction factor and the capacity deterioration correction factor.

20. The method as claimed in claim 19, wherein the internal resistance deterioration correction factor is calculated on the basis of the internal resistance calculated from a battery discharge I-V characteristic obtained from a current value and a voltage value of the battery during discharge, and the capacity deterioration correction factor is calculated on the basis of the battery dischargeable capacity calculated from a relationship between a battery discharged power amount and an estimated open-circuit voltage obtained from the battery discharge I-V characteristic.

21. The method as claimed in claim 19, wherein the internal resistance deterioration correction factor is calculated on the basis of a full charged power calculated from a discharge current and a terminal voltage of the battery in a full charged condition and a temperature corrected power calculated from a temperature and the battery characteristic.

22. The method as claimed in claim 19, wherein the capacity deterioration correction factor is calculated from the internal resistance deterioration correction factor and a correlation between the internal resistance deterioration correction factor and the capacity deterioration correction factor which correlation is obtained from practically measured values of the change of the capacity of the battery and the deterioration of the output of the battery.

23. The method as claimed in claim 19, wherein the internal resistance deterioration correction factor is calculated by averaging calculation values of the internal resistance deterioration correction factor calculated at predetermined intervals.

24. The method as claimed in claim 19, wherein the capacity deterioration correction factor is calculating by averaging calculation values of the capacity change correction factor calculated at predetermined intervals.

25. The method as claimed in claim 19, wherein the internal resistance deterioration correction factor is calculated by averaging last two calculation values of the internal resistance deterioration correction factor calculated at predetermined intervals.

26. The method as claimed in claim 19, wherein the capacity deterioration correction factor is calculating by averaging last two calculation values of capacity change correction factor calculated at predetermined intervals.

27. The method as claimed in claim 19, wherein the internal resistance deterioration correction factor is calculated from a ratio between an initial internal resistance obtained from an initial battery discharge characteristic and a present internal resistance obtained from a present battery discharge characteristic.

28. The method as claimed in claim 19, wherein the capacity deterioration correction factor is calculated from a ratio between an new-battery capacity obtained from a new-battery discharge characteristic and a present internal resistance obtained from a present-battery discharge characteristic.

29. The method as claimed in claim 19, wherein the internal resistance deterioration correction factor is calculated by comparing a new-battery discharge I-V characteristic and an actual discharge I-V characteristic.

30. The method as claimed in claim 19, wherein the capacity deterioration correction factor β

is obtained from the following equations;

space="preserve" listing-type="equation">E=Vf-C·

K

space="preserve" listing-type="equation">C0=(Vf-Ve)/K0

space="preserve" listing-type="equation">Cd=(Vf'"'"'-Ve)/Kd

space="preserve" listing-type="equation">β

=Cd/C0

wherein E is an open-circuit voltage, K is a gradient of the characteristic line of each battery, Vf and Vf'"'"' are voltage intercepts of the characteristic line of a new battery and of a deteriorated battery, Ve is a predetermined discharge capacity reference voltage, and C0 and Cd are battery capacities of the new battery and the deteriorated battery.

31. The method of estimating a residual energy of a battery comprising the steps of:

calculating a dischargeable amount of the battery from a corrected battery characteristic obtained by a battery characteristic correcting method; and

calculating the residual energy of the battery from the dischargeable amount and a discharge power integrating amount of the battery, wherein

the battery characteristic correcting method comprises the steps of

calculating a temperature correction factor representative of a degree of a temperature dependency of the battery characteristic,

calculating an internal resistance deterioration correction factor representative of a ratio between an internal resistance of a new battery and that of a deteriorated battery,

calculating a capacity deterioration correction factor representative of a ratio between a dischargeable power amount of the new battery and that of the deteriorated battery, and

correcting the battery characteristic on the basis of the temperature correction factor, the internal resistance deterioration correction factor and the capacity deterioration correction factor.