SYSTEMS AND METHODS FOR BATTERY STATE ESTIMATION

• US 20150219726A1
• Filed: 02/03/2014
• Published: 08/06/2015
• Est. Priority Date: 02/03/2014
• Status: Abandoned Application

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: BARASZU, ROBERT C., LENZ, JOCHEN
• Application Number:
  US14/171,334
• Publication Number:
  US 20150219726A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• 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

Abstract

System and methods for estimating a state of a battery utilizing an adaptive battery model are presented. The model may utilize a multi-RC electric circuit model designed to represent an open circuit voltage and/or an impedance of an actual battery system. A state observer may be utilized in connection with estimating parameters associated with a model of the battery system (e.g., resistances in the multi-RC circuit model). Systems and methods disclosed herein may further employ a blending technique utilizing an Ah-based SOC determination and an OCV-based SOC determination in estimating a state of a battery system.

Claims

1. A method of determining a state of a subdivision of a battery system, the method comprising:

receiving a current measurement signal from the subdivision;

receiving a difference signal associated with a difference between a measured open circuit voltage of the subdivision and a modeled open circuit voltage generated from a model of the subdivision;

applying a correction to the received current measurement signal based, at least in part, on the difference signal to generate a corrected current measurement signal; and

estimating a state of the subdivision based on the corrected current measurement signal.

2. The method of claim 1, wherein the state of the subdivision comprises a state of charge of the subdivision.

3. The method of claim 1, wherein the subdivision comprises a battery cell of the battery system.

4. The method of claim 1, wherein the subdivision comprises a battery pack of the battery system.

5. The method of claim 1, wherein the model of the subdivision comprises a multi-RC circuit model comprising a plurality of resistors and a plurality of capacitors.

6. The method of claim 5, wherein each of the plurality of capacitors have capacitances associated with predefined time constants.

7. The method of claim 5, wherein each of the plurality of resistors have resistances estimated based on a measured parameter of the subdivision.

8. The method of claim 7, wherein the resistances are estimated using a state observer, the resistances being a state parameter of the state observer.

9. The method of claim 8, wherein the state observer comprises a Luenberger observer.

10. The method of claim 1, wherein the method further comprises applying an approximative real-time Fourier transform to the difference signal prior to applying the correction.

20. The non-transitory computer-readable medium of claim 1, wherein instructions are further configured to cause the processor to apply an approximative real-time Fourier transform to the difference signal prior to applying the correction.

11. A non-transitory computer-readable medium comprising instructions that, when executed by a processor, cause the processor to perform a method of determining a state of a subdivision of a battery system comprising:

receiving a current measurement signal from the subdivision;

receiving a difference signal associated with a difference between a measured open circuit voltage of the subdivision and a modeled open circuit voltage generated from a model of the subdivision;

applying a correction to the received current measurement signal based, at least in part, on the difference signal to generate a corrected current measurement signal; and

estimating a state of the subdivision based on the corrected current measurement signal.

12. The non-transitory computer-readable medium of claim 11, wherein the state of the subdivision comprises a state of charge of the subdivision.

13. The non-transitory computer-readable medium of claim 11, wherein the subdivision comprises a battery cell of the battery system.

14. The non-transitory computer-readable medium of claim 11, wherein the subdivision comprises a battery pack of the battery system.

15. The non-transitory computer-readable medium of claim 11, wherein the model of the subdivision comprises a multi-RC circuit model comprising a plurality of resistors and a plurality of capacitors.

16. The non-transitory computer-readable medium of claim 15, wherein each of the plurality of capacitors have capacitances associated with predefined time constants.

17. The non-transitory computer-readable medium of claim 15, wherein each of the plurality of resistors have resistances estimated based on a measured parameter of the subdivision.

18. The non-transitory computer-readable medium of claim 17, wherein the resistances are estimated using a state observer, the resistances being a state parameter of the state observer.

19. The non-transitory computer-readable medium of claim 18, wherein the state observer comprises a Luenberger observer.