Systems and methods for determining battery system power capability

Patent metadata

Field	Value
Publication number	US-9419314-B2
Application number	US-201414275553-A
Country	US
Kind code	B2
Filing date	May 12, 2014
Priority date	May 12, 2014
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

System and methods for determining battery system power capability in a vehicle are presented. Peak power capability estimation systems and methods disclosed herein may compensate regressed parameters in a battery system circuit model for an effect of current magnitude. Utilizing the disclosed methods for accurately estimating peak power capability of a battery system may provide for, among other things, improved battery system performance modeling and/or improved battery system control and management decisions.

First claim

The invention claimed is:

1. A method of determining a peak power capability of a battery system comprising:
identifying a peak current of the battery system;
determining a regressed ohmic resistance in a battery system model used to model the battery system;
scaling the regressed ohmic resistance to calculate a compensated ohmic resistance of the battery system model based on the peak current;
determining a peak power capability of the battery system based on the compensated ohmic resistance and the battery system model; and
implementing a control action in a vehicle associated with the battery system based on the determined peak power capability.

2. The method of claim 1 , wherein the peak power capability comprises a current-limited peak power capability and the peak current of the battery system comprises a maximum current limit of the battery system.

3. The method of claim 1 , wherein the peak power capability comprises a voltage-limited peak power capability and identifying the peak current comprises:
generating a guessed current;
determining a guessed resistance based on the guessed current using current dependent resistance information;
determining a calculated current based on the guessed resistance; and
determining whether a difference between the calculated current and the guessed current is below a threshold.

4. The method of claim 3 , wherein if the difference between the calculated current and the guessed current is below the threshold, identifying the peak current comprises:
identifying the calculated current as the peak current.

5. The method of claim 3 , wherein if the difference between the calculated current and the guessed current is not below the threshold, identifying the peak current comprises:
iteratively generating subsequent guessed currents, determining subsequent guessed resistances based on the subsequent guessed currents, and determining subsequent calculated currents based on the subsequent guessed currents until a difference between a final subsequent calculated current and a final subsequent guessed current is below the threshold; and
identifying the final subsequent calculated current as the peak current.

6. The method of claim 1 , wherein scaling the regressed ohmic resistance to calculate a compensated ohmic resistance further comprises:
determining a peak resistance based on the peak current;
determining a nominal resistance based on an average current associated with a regression operation used to calculate the regressed ohmic resistance; and
scaling the regressed ohmic resistance by a ratio of the peak resistance to the nominal resistance to calculate the compensated ohmic resistance.

7. The method of claim 1 , wherein the model comprises a circuit model including elements configured to model ohmic resistance, charge transfer, and mass transfer processes of the battery system.

8. The method of claim 1 , wherein the control action comprises an action associated with a regenerative braking acceptance setting of the vehicle.

9. The method of claim 1 , wherein the control action comprises an action associated with a maximum allowed vehicle acceleration.

10. The method of claim 1 , wherein the control action comprises an action associated with initiation of an electric drivetrain system of the vehicle.

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 peak power capability of a battery system, the method comprising:
identifying a peak current of the battery system;
determining a regressed ohmic resistance in a battery system model used to model the battery system;
scaling the regressed ohmic resistance to calculate a compensated ohmic resistance of the battery system model based on the peak current;
determining a peak power capability of the battery system based on the compensated ohmic resistance and the battery system model; and
implementing a control action in a vehicle associated with the battery system based on the determined peak power capability.

12. The non-transitory computer-readable medium of claim 11 , wherein the control action comprises an action associated with a regenerative braking acceptance setting of the vehicle.

13. The non-transitory computer-readable medium of claim 11 , wherein the peak power capability comprises a current-limited peak power capability and the peak current of the battery system comprises a maximum current limit of the battery system.

14. The non-transitory computer-readable medium of claim 11 , wherein the peak power capability comprises a voltage-limited peak power capability and identifying the peak current comprises:
generating a guessed current;
determining a guessed resistance based on the guessed current using current dependent resistance information;
determining a calculated current based on the guessed resistance; and
determining whether a difference between the calculated current and the guessed current is below a threshold.

15. The non-transitory computer-readable medium of claim 14 , wherein if the difference between the calculated current and the guessed current is below the threshold, identifying the peak current comprises:
identifying the calculated current as the peak current.

16. The non-transitory computer-readable medium of claim 14 , wherein if the difference between the calculated current and the guessed current is not below the threshold, identifying the peak current comprises:
iteratively generating subsequent guessed currents, determining subsequent guessed resistances based on the subsequent guessed currents, and determining subsequent calculated currents based on the subsequent guessed currents until a difference between a final subsequent calculated current and a final subsequent guessed current is below the threshold; and
identifying the final subsequent calculated current as the peak current.

17. The non-transitory computer-readable medium of claim 11 , wherein scaling the regressed ohmic resistance to calculate a compensated ohmic resistance further comprises:
determining a peak resistance based on the peak current;
determining a nominal resistance based on an average current associated with a regression operation used to calculate the regressed ohmic resistance; and
scaling the regressed ohmic resistance by a ratio of the peak resistance to the nominal resistance to calculate the compensated ohmic resistance.

18. The non-transitory computer-readable medium of claim 11 , wherein the control action comprises an action associated with a maximum allowed vehicle acceleration.

19. The non-transitory computer-readable medium of claim 11 , wherein the control action comprises an action associated with initiation of an electric drivetrain system of the vehicle.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Koch Brian J
• Stawinski Brett B
• Frost Patrick
• Frisch Damon R
• Novak John E

Classifications

• G01R21/14 Primary

  Compensating for temperature change · CPC title

• H01M10/48 Primary

  Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title

• H01M10/482

  for several batteries or cells simultaneously or sequentially · CPC title

• B60L15/20

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title

• B60L11/1851

  Operations & Transport · mapped topic