Estimation of State-Of-Health in Batteries

• US 20110060538A1
• Filed: 09/07/2010
• Published: 03/10/2011
• Est. Priority Date: 09/04/2009
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Banaei, Anahita, Fahimi, Babak
• Granted Patent: US 9,366,732 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

Methods and apparatuses for estimation of a state-of-health in a battery are disclosed. An example method comprises: determining if a terminal voltage of the chemical battery differs from a calculated terminal voltage; in response to determining that the terminal voltage of the chemical battery differs from the calculated terminal voltage, calculating a range of voltages by taking the convolution of a terminal current of the chemical battery with a range of impulse responses from a look up table of impulse responses corresponding to different states-of-health; comparing the terminal voltage of the chemical battery with the range of calculated voltages to determine a second impulse response that corresponds to the case where the terminal voltage matches the calculated voltage; and using the look up table of impulse responses corresponding to different states-of-health to determine the state-of-health of the chemical battery from the second impulse response. Other embodiments are described and claimed.

Claims

1. A method for online estimation of a state-of-health in a chemical battery, the method comprising:

determining if a terminal voltage of the chemical battery differs from a calculated terminal voltage;

in response to determining that the terminal voltage of the chemical battery differs from the calculated terminal voltage, calculating a range of voltages by taking the convolution of a terminal current of the chemical battery with a range of impulse responses from a look up table of impulse responses corresponding to different states-of-health;

comparing the terminal voltage of the chemical battery with the range of calculated voltages to determine a second impulse response that corresponds to the case where the terminal voltage matches the calculated voltage; and

using the look up table of impulse responses corresponding to different states-of-health to determine the state-of-health of the chemical battery from the second impulse response.

2. The method of claim 1, wherein determining if the terminal voltage of the chemical battery differs from the calculated terminal voltage comprises:

measuring the terminal current of the chemical battery;

measuring the terminal voltage of the chemical battery;

estimating a state-of-charge of the chemical battery;

determining a first impulse response of the chemical battery corresponding to the estimated state-of-charge of the chemical battery; and

calculating the terminal voltage of the chemical battery.

3. The method of claim 2, further comprising estimating the state-of-charge of the chemical battery from the terminal current of the chemical battery and the terminal voltage of the chemical battery.

4. The method of claim 2, wherein the first impulse response of the chemical battery corresponding to the estimated state-of-charge of the chemical battery is determined from a look up table of impulse responses corresponding to different states-of-charge.

5. The method of claim 2, wherein the calculated terminal voltage of the chemical battery is calculated by taking the convolution of the measured terminal current with the first impulse response.

6. The method of claim 1, wherein determining if the terminal voltage of the chemical battery differs from the calculated terminal voltage comprises:

measuring the terminal current of the chemical battery;

measuring the terminal voltage of the chemical battery;

measuring a temperature of the chemical battery;

estimating a state-of-charge of the chemical battery;

determining a first impulse response of the chemical battery corresponding to the estimated state-of-charge of the chemical battery; and

calculating the terminal voltage of the chemical battery.

7. The method of claim 6, further comprising estimating the state-of-charge of the chemical battery from the terminal current of the chemical battery, the terminal voltage of the chemical battery, and the temperature of the chemical battery.

8. The method of claim 6, wherein the first impulse response of the chemical battery corresponding to the estimated state-of-charge of the chemical battery is determined from a look up table of impulse responses corresponding to different states-of-charge and temperature.

9. The method of claim 6, further comprising:

in response to determining that the measured terminal voltage of the chemical battery differs from the calculated terminal voltage, calculating the range of voltages at the temperature of the chemical battery by taking the convolution of the terminal current of the chemical battery with the range of impulse responses at the temperature of the chemical battery from a look up table of impulse responses corresponding to different states-of-health and temperatures; and

using the look up table of impulse responses corresponding to different states-of-health and temperatures to determine the state-of-health of the chemical battery from the second impulse response.

10. The method of claim 1, further comprising:

calculating a second range of voltages by taking the convolution of a second terminal current of the chemical battery with the range of impulse responses from the look up table of impulse responses corresponding to different states-of-health;

comparing a second terminal voltage of the chemical battery with the second range of calculated voltages to determine a third impulse response that corresponds to the case where the second terminal voltage matches the second calculated voltage; and

using the look up table of impulse responses corresponding to different states-of-health to identify a fault in the chemical battery.

11. The method of claim 10, further comprising:

measuring a second terminal current of the chemical battery;

measuring a second terminal voltage of the chemical battery;

measuring a temperature of the chemical battery;

calculating the second range of voltages at the temperature of the chemical battery by taking the convolution of the second terminal current of the chemical battery with the range of impulse responses at the temperature of the chemical battery from a look up table of impulse responses corresponding to different states-of-health and temperature; and

using the look up table of impulse responses corresponding to different states-of-health and temperatures to identify a fault in the chemical battery.

12. The method of claim 1, further comprising estimating the lifetime of the chemical battery by comparing a fitness percentage of a healthy chemical battery impulse response with the fitness percentage of the second impulse response.

13. The method of claim 1, wherein the chemical battery comprises a Li-Ion battery, a Ni-MH battery, a Ni—

Cd battery, or a Lead-Acid battery.

14. The method of claim 1, further comprising estimating the online state-of-health of a plurality of chemical batteries.

15. An apparatus for estimating a state-of-health in an online chemical battery, the apparatus comprising:

one or more processors; and

one or more memory units coupled to the processors,

the apparatus being configured to;

determine if a terminal voltage of the chemical battery differs from a calculated terminal voltage;

in response to determining that the terminal voltage of the chemical battery differs from the calculated terminal voltage, calculate a range of voltages by taking the convolution of a terminal current of the chemical battery with a range of impulse responses from a look up table of impulse responses corresponding to different states-of-health;

compare the terminal voltage of the chemical battery with the range of calculated voltages to determine a second impulse response that corresponds to the case where the terminal voltage matches the calculated voltage; and

use the look up table of impulse responses corresponding to different states-of-health to determine the state-of-health of the chemical battery from the second impulse response.

16. The apparatus of claim 15, wherein the apparatus being configured to determine if the terminal voltage of the chemical battery differs from the calculated terminal voltage comprises the apparatus being configured to:

measure the terminal current of the chemical battery;

measure the terminal voltage of the chemical battery;

estimate a state-of-charge of the chemical battery;

determine a first impulse response of the chemical battery corresponding to the estimated state-of-charge of the chemical battery; and

calculate the terminal voltage of the chemical battery.

17. The apparatus of claim 15, wherein the apparatus being configured to determine if the terminal voltage of the chemical battery differs from the calculated terminal voltage comprises the apparatus being configured to:

measure the terminal current of the chemical battery;

measure the terminal voltage of the chemical battery;

measure a temperature of the chemical battery;

estimate a state-of-charge of the chemical battery;

determine a first impulse response of the chemical battery corresponding to the estimated state-of-charge of the chemical battery; and

calculate the terminal voltage of the chemical battery.

18. The apparatus of claim 15, wherein the apparatus is further configured to:

calculate a second range of voltages by taking the convolution of a second terminal current of the chemical battery with the range of impulse responses from the look up table of impulse responses corresponding to different states-of-health;

compare a second terminal voltage of the chemical battery with the second range of calculated voltages to determine a third impulse response that corresponds to the case where the second terminal voltage matches the second calculated voltage; and

use the look up table of impulse responses corresponding to different states-of-health to identify a fault in the chemical battery.

19. The apparatus of claim 18, wherein the apparatus is further configured to:

measure a second terminal current of the chemical battery;

measure a second terminal voltage of the chemical battery;

measure a temperature of the chemical battery;

calculate the second range of voltages at the temperature of the chemical battery by taking the convolution of the second terminal current of the chemical battery with the range of impulse responses at the temperature of the chemical battery from a look up table of impulse responses corresponding to different states-of-health and temperature; and

use the look up table of impulse responses corresponding to different states-of-health and temperatures to identify a fault in the chemical battery.

20. An apparatus for online estimation of a state-of-health in a chemical battery, comprising:

means for determining if a terminal voltage of the chemical battery differs from a calculated terminal voltage;

in response to means for determining that the terminal voltage of the chemical battery differs from the calculated terminal voltage, means for calculating a range of voltages by taking the convolution of a terminal current of the chemical battery with a range of impulse responses from a look up table of impulse responses corresponding to different states-of-health;

means for comparing the terminal voltage of the chemical battery with the range of calculated voltages to determine a second impulse response that corresponds to the case where the terminal voltage matches the calculated voltage; and

means for using the look up table of impulse responses corresponding to different states-of-health to determine the state-of-health of the chemical battery from the second impulse response.

21. An apparatus, comprising:

a battery;

a state-of-charge (SOC) Estimator coupled to the battery;

a first look up table coupled to the SOC Estimator;

a second look up table receiving a measured temperature of the battery;

a first convolution device coupled to the first look up table and a pattern recognition device;

a second convolution device coupled to the second look up table and the pattern recognition device; and

the pattern recognition device coupled to the battery, the first convolution device, and the second convolution device, wherein the pattern recognition device receives a calculated voltage of the battery, a measured voltage of the battery, and a calculated range of voltages and outputs at least one of;

a state-of-health of the battery, a possible fault of the battery, and a life time of the battery.

22. The apparatus of claim 21, wherein the SOC Estimator receives a measured terminal current of the battery, the measured temperature of the battery, and the measured voltage of the battery and outputs a state-of-charge of the battery.

23. The apparatus of claim 21 wherein the first look up table includes impulse responses related to different SOCs and temperatures for a healthy battery.

24. The apparatus of claim 21 wherein the second look up table includes impulse responses related to different faults and temperatures for an unhealthy battery.

25. The apparatus of claim 21 wherein the first convolution device receives an impulse response and outputs the calculated voltage of the battery to the pattern recognition device.

26. The apparatus of claim 21 wherein the second convolution device receives a range of impulse responses from the second look up table and outputs the calculated range of voltages.