Method and system for battery parameter estimation

• US 7,315,789 B2
• Filed: 11/23/2004
• Issued: 01/01/2008
• Est. Priority Date: 11/23/2004
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Plett, Gregory L.
• Primary Examiner(s): WACHSMAN, HAL D
• Application Number:
  US10/996,887
• Publication Number:
  US 20060111854A1
• Time in Patent Office: 1,134 Days
• Field of Search: 702 63- 65, 702/57, 702/58, 702/60, 702/130, 702/136, 702/179, 702/181, 702/187, 702/190, 702/185, 702/182, 702/183, 320/132, 320/127, 320149-150, 320/134, 320/136, 320/101
• 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 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

Methods and systems for predicting a cell capacity associated with a cell of an electrochemical cell system are provided. In one exemplary embodiment, the method determines a first predicate cell capacity of the cell of the electrochemical cell system. The method further includes measuring a voltage of the cell to obtain a measured voltage. The method further includes determining a corrected predicted cell capacity of the cell based on the first predicted cell capacity, the measured voltage, and a gain factor.

Claims

1. A method for predicting a cell capacity associated with a cell of an electrochemical cell system, comprising:

determining a first predicted cell capacity of the cell of the electrochemical cell system;

measuring a voltage of the cell to obtain a measured voltage;

determining a difference between the measured voltage and an estimated voltage to obtain a difference value;

multiplying the difference value by a first gain factor to obtain a first correction value;

summing the correction value by the first predicted cell capacity to obtain a corrected predicted cell capacity of the cell; and

storing the corrected predicted cell capacity of the cell in a storage medium.

2. The method of claim 1, further comprising:

measuring a temperature of the cell to obtain a measured temperature, wherein the corrected predicted cell capacity is also based on the measured temperature.

3. The method of claim 1, further comprising:

measuring a current of the cell to obtain a measured current, wherein the corrected predicted cell capacity is also based on the measured current.

4. The method of claim 1, further comprises:

determining a first predicted resistance of the cell;

multiplying the difference value by a second gain factor to obtain a second correction value;

summing the second correction value by the first predicted resistance of the cell to obtain a corrected predicted resistance of the cell; and

storing the corrected predicted resistance of the cell in the storage medium.

5. The method of claim 1, further comprising:

determining a first predicted polarization voltage time constant of the cell;

multiplying the difference value by a second gain factor to obtain a second correction value;

summing the second correction value by the first predicted polarization voltage time constant of the cell to obtain a corrected predicted polarization voltage time constant of the cell; and

storing the corrected predicted polarization voltage time constant of the cell in the storage medium.

6. The method of claim 1, further comprises:

determining a first predicted polarization voltage blending factor of the cell;

multiplying the difference value by a second gain factor to obtain a second correction value;

summing the second correction value by the first predicted polarization voltage blending factor of the cell to obtain a corrected predicted polarization voltage blending factor of the cell; and

storing the corrected predicted polarization voltage blending factor of the cell in the storage medium.

7. The method of claim 1, further comprising:

determining a first predicted hysteresis blending factor of the cell;

multiplying the difference value by a second gain factor to obtain a second corrected value;

summing the second correction value by the first predicted hysteresis blending factor of the cell to obtain a corrected predicted hysteresis blending factor of the cell; and

storing the corrected predicted hysteresis blending factor of the cell in the storage medium.

8. The method of claim 1, further comprising:

determining a first predicted hysteresis rate of the cell;

multiplying the difference value by a second gain factor to obtain a second correction value;

summing the second correction value by the first predicted hysteresis rate of the cell to obtain a corrected predicted hysteresis rate of the cell; and

storing the corrected predicted hysteresis rate of the cell in the storage medium.

9. The method of claim 1, further comprising:

determining a first predicted efficiency factor of the cell;

multiplying the difference value by a second gain factor to obtain a second correction value;

summing the second correction value by the first predicted efficiency factor of the cell to obtain a corrected predicted efficiency factor of the cell; and

storing the corrected predicted efficiency factor of the cell in the storage medium.

10. The method of claim 1, further comprising:

determining a first predicted uncertainty associated with the first predicted cell capacity;

determining the first gain factor based on the predicted uncertainty; and

determining a corrected predicted uncertainty associated with the corrected predicted cell capacity based on the first predicted uncertainty and a second gain factor.

11. The method of claim 1 wherein the corrected predicted cell capacity is also determined utilizing at least one of a Kalman Filter and an extended Kalman Filter.

12. The method of claim 1, further comprising ensuring convergence of the corrected predicted cell capacity to a respective physical cell capacity.

13. The method of claim 12 wherein said ensuring includes forcing a dc gain of a voltage polarization filter to be zero.

14. The method of claim 1 further comprising ensuring stability of a model dynamics of the electrochemical cell system by forcing filter poles to have a magnitude less than 1.

15. A system for predicting a cell capacity associated with a cell of an electrochemical cell system, comprising:

a voltage sensor configured to measure a voltage of the cell of the electrochemical cell system to obtain a measured voltage; and

an arithmetic circuit operably coupled to the voltage sensor, the arithmetic circuit configured to determine a first predicted cell capacity of the cell, the arithmetic circuit further configured to determine a difference between the measured voltage and an estimated voltage to obtain a difference value, the arithmetic circuit further configured to multiply the difference value by a first gain factor to obtain a first correction value, the arithmetic circuit further configured to sum the first correction value by the first predicted cell capacity to obtain a corrected predicted cell capacity of the cell, the arithmetic circuit further configured to store the corrected predicted cell capacity of the cell in a storage medium.

16. The system of claim 15, further comprising

a temperature sensor configured to measure a temperature of the cell to obtain a measured temperature, the temperature sensor operably coupled to the arithmetic circuit, wherein the corrected predicted cell capacity is also based on the measured temperature.

17. The system of claim 15, further comprising:

a current sensor configured to measure a current of the cell to obtain a measured current, the current sensor operably coupled to the arithmetic circuit, wherein the corrected predicted cell capacity is also based on the measured current.

18. The system of claim 15, wherein the arithmetic circuit is further configured to determine a first predicted resistance of the cell, the arithmetic circuit further configured to multiply the difference value by a second gain factor to obtain a second correction value, the arithmetic circuit further configured to sum the second correction value by the first predicted resistance of the cell to obtain a corrected predicted resistance of the cell, the arithmetic circuit further configured to store the corrected predicted resistance of the cell in the storage medium.

19. The system of claim 15, wherein the arithmetic circuit is further configured to determine a first predicted uncertainty associated with the first predicted cell capacity, the arithmetic circuit further configured to determine the first gain factor based on the first predicted uncertainty, the arithmetic circuit further configured to determine a corrected predicted uncertainty associated with the corrected predicted cell capacity based on the first predicted uncertainty and a second gain factor, the arithmetic circuit further configured to store the corrected predicted cell capacity in the storage medium.

20. A method for predicting a resistance associated with a cell of an electrochemical cell system, comprising:

determining a first predicted resistance of the cell of the electrochemical cell system;

measuring a voltage of the cell to obtain a measured voltage;

determining a difference between the measured voltage and an estimated voltage to obtain a difference value;

multiplying the difference value by a gain factor to obtain a correction value;

summing the correction value by the first predicted resistance of the cell to obtain a corrected predicted resistance of the cell; and

storing the corrected predicted resistance of the cell in the storage medium.

21. A system for predicting a resistance associated with a cell of an electrochemical cell system, comprising:

a voltage sensor configured to measure a voltage of the cell of the electrochemical cell system to obtain a measured voltage; and

an arithmetic circuit operably coupled to the voltage sensor, the arithmetic circuit configured to determine a first predicted resistance of the cell, the arithmetic circuit further configured to determine a difference between the measured voltage and an estimated voltage to obtain a difference value, the arithmetic circuit further configured to multiply the difference value by a gain factor to obtain a correction value, the arithmetic circuit further configured to sum the correction value by the first predicted resistance of the cell to obtain a corrected predicted resistance of the cell, the arithmetic circuit further configured to store the corrected predicted resistance of the cell in the storage medium.

22. A computer program product for predicting a cell capacity associated with a cell of an electrochemical cell system, the computer program product comprising:

a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for facilitating a method comprising;

determining a first predicted cell capacity of the cell of the electrochemical cell system;

measuring a voltage of the cell to obtain a measured voltage;

determining a difference between the measured voltage and an estimated voltage to obtain a difference value;

multiplying the difference value by a gain factor to obtain a correction value;

summing the correction value by the first predicted cell capacity to obtain a corrected predicted cell capacity of the cell; and

storing the corrected predicted cell capacity of the cell in the storage medium.

23. A computer program product for predicting a resistance associated with a cell of an electrochemical cell system, the computer program product comprising:

a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for facilitating a method comprising;

determining a first predicted resistance of the cell of the electrochemical cell system;

measuring a voltage of the cell to obtain a measured voltage;

determining a difference between the measured voltage and an estimated voltage to obtain a difference value;

multiplying the difference value by a gain factor to obtain a correction value;

summing the correction value by the first predicted resistance of the cell to obtain a corrected predicted resistance of the cell; and

storing the corrected predicted resistance of the cell in the storage medium.