Method and apparatus for real-time life estimation of an electric energy storage device

• US 7,598,712 B2
• Filed: 06/07/2006
• Issued: 10/06/2009
• Est. Priority Date: 06/07/2006
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Zettel, Andrew M., Heap, Anthony H.
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US11/422,652
• Publication Number:
  US 20070285059A1
• Time in Patent Office: 1,217 Days
• Field of Search: 320/104, 320/132, 320/150, 320/153, 324/430, 324/431, 324/432, 324/434
• US Class Current: 320/150
• CPC Class Codes: B60L 2260/56 Temperature prediction, e.g. for pre-cooling
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/25 by controlling the electric load
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• 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 31/3832 without measurement of battery voltage
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Sate-of-life for an electrical energy storage device is predictively determined based on electrical current, state-of-charge, and temperature of the electrical energy storage device during active and quiescent periods of operation.

Claims

1. Method to determine state-of-life of an electrical energy storage device, comprising:

monitoring electrical current through the electrical energy storage device;

monitoring a state-of-charge of the electrical energy storage device;

monitoring temperature of the electrical energy storage device during active periods of operation characterized by electrical current flow through the electrical energy storage;

monitoring temperature of the electrical energy storage device during quiescent periods of operation characterized by de minimis electrical current through the electrical energy storage device;

determining a state-of-life of the electrical energy storage device based upon the electrical current, the state-of-charge, and the temperature of the electrical energy storage device during the active periods of operation and during the quiescent periods of operation;

detecting an internal resistance change over time that is greater than a minimum amount; and

fixing the state-of-life to a predetermined value when the internal resistance is greater than the minimum amount.

2. The method of claim 1, wherein monitoring electrical current through the electrical energy storage device comprises calculating a time-integral of the electrical current during active periods of operation.

3. The method of claim 1, wherein the determined life expectancy of the electrical energy storage device is utilized in a control system for a hybrid vehicle.

4. The method of claim 1, wherein said electrical energy storage device is operative to exchange electrical energy with an electric machine.

5. The method of claim 4, wherein monitoring temperature of the electrical energy storage device during active periods of operation comprises monitoring the temperature when the electrical machine is operative.

6. The method of claim 3, wherein monitoring temperature of the electrical energy storage device during quiescent periods of operation comprises monitoring the temperature when the electrical machine is inoperative.

7. The method of claim 1, further comprising monitoring internal resistance of the electrical energy storage device and wherein determining the state-of-life is further based upon said internal resistance.

8. The method of claim 7, wherein determining state-of-life includes fixing state-of-life to the predetermined value when a characteristic knee is identified in a measured resistance curve of said internal resistance, indicating an incipient end of life of the electrical energy storage device.

9. The method of claim 7, further comprising reducing electrical energy storage device power limits when incipient end of life of the electrical energy storage device is indicated.

10. The method of claim 3, wherein active periods of operation comprise periods when the electrical machine is operative.

11. The method of claim 3, wherein quiescent periods of operation comprise periods when the electrical machine is inoperative.

12. Apparatus for determining state-of-life of an electrical energy storage device, comprising:

a temperature sensor adapted for sensing temperature of the energy storage device; and

a computer based controller adapted to receive a signal indicative of sensed energy storage device temperature;

said computer based controller including a storage medium having a computer program encoded therein, said computer program comprising;

code for monitoring electrical current through the electrical energy storage device;

code for monitoring a state-of-charge of the electrical energy storage device;

code for monitoring temperature of the electrical energy storage device during active periods of operation characterized by electrical current flow through the electrical energy storage;

code for monitoring temperature of the electrical energy storage device during quiescent periods of operation characterized by de minimis electrical current through the electrical energy storage device;

code for monitoring a state-of-life of the electrical energy storage device based upon the electrical current, the state-of-charge, and the temperature of the electrical energy storage device during the active periods of operation and during the quiescent periods of operation;

code to determine state-of-life of the electrical energy storage device, based upon the electrical current, the state-of-charge of the electrical energy storage device, and the temperature of the electrical energy storage device during active periods of operation and during quiescent periods of operation;

code for detecting an internal resistance change over time that is greater than a minimum amount; and

code for fixing the state-of-life to a predetermined value when the internal resistance is greater than the minimum amount.

13. The apparatus of claim 12, wherein the code for monitoring electrical current comprises code for calculating a time-integral of the electrical current during active periods of operation.

14. The apparatus of claim 12, wherein the computer program further comprises code to monitor internal resistance of the electrical energy storage device and wherein the code to determine state-of-life is further based upon said internal resistance.

15. The apparatus of claim 14, wherein the code to determine the state-of-life includes code for fixing state-of-life to a predetermined value when a characteristic knee is identified in a measured resistance curve of said internal resistance indicating incipient end of life of the electrical energy storage device.

16. The apparatus of claim 15, wherein the computer program further comprises code to reduce electrical energy storage device power limits when the incipient end of life of the electrical energy storage device is indicated.

17. The apparatus of claim 12, wherein said electrical energy storage device comprises a vehicular electrical energy storage device.