BATTERY DIFFUSION VOLTAGE ESTIMATION

• US 20120136595A1
• Filed: 09/12/2011
• Published: 05/31/2012
• Est. Priority Date: 11/29/2010
• Status: Abandoned Application

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Tang, Xidong, Lin, Jian, Koch, Brian J., Johnson, Kurt M., Thorsen, Benjamin
• Application Number:
  US13/229,931
• Publication Number:
  US 20120136595A1
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/48 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 Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method includes estimating a first diffusion voltage value of a battery by selecting the first diffusion voltage value from a look-up table, estimating a second diffusion voltage value of the battery using an estimation procedure, selecting at least one of the estimated first and second diffusion voltage values, and determining an open circuit voltage of the battery based at least in part on the selected diffusion voltage value. The method may be implemented by a computing device in a vehicle.

Claims

1. A method comprising:

estimating a first diffusion voltage value of a battery by selecting the first diffusion voltage value from a look-up table;

estimating a second diffusion voltage value of the battery using an estimation procedure;

selecting at least one of the estimated first and second diffusion voltage values; and

determining, via a computing device, an open circuit voltage of the battery based at least in part on the selected diffusion voltage value.

2. A method as set forth in claim 1, further comprising determining at least one of a terminal voltage, an accumulated charge, and a temperature of the battery.

3. A method as set forth in claim 2, wherein estimating the first diffusion voltage value includes selecting the first diffusion voltage value from the look-up table based at least in part on one or more of the terminal voltage, the accumulated charge, and the temperature.

4. A method as set forth in claim 2, wherein the estimation procedure includes:

estimating a first set of parameter values associated with a state of health of the battery;

calculating, via the computing device, a double layer voltage based at least in part on the estimated parameter values;

determining a change in an open circuit voltage of the battery over time; and

estimating a second set of parameter values associated with the state of health of the battery.

5. A method as set forth in claim 4, wherein estimating the second diffusion voltage value includes estimating the second diffusion voltage value based at least in part on one or more of the terminal voltage, the accumulated charge, and the second set of parameter values.

6. A method as set forth in claim 4, wherein determining the change in the open circuit voltage includes:

determining a change in the state of charge of the battery; and

deriving the change in the open circuit voltage from the change in the state of charge.

7. A method as set forth in claim 4, wherein estimating the first set of parameter values includes applying a regression procedure to the first set of parameter values.

8. A method as set forth in claim 4, wherein estimating the second set of parameter values includes applying a regression procedure to the second set of parameter values.

9. A method as set forth in claim 2, wherein determining the open circuit voltage includes determining the open circuit voltage based at least in part on the selected diffusion voltage value and one or more of the terminal voltage, the accumulated charge, and the temperature.

10. A method as set forth in claim 1, wherein selecting at least one of the estimated first and second diffusion voltage values includes determining the validity of one or more of the first and second diffusion voltage values.

11. A method as set forth in claim 1, further comprising applying a filter procedure to the selected diffusion voltage value prior to determining the open circuit voltage.

12. A vehicle comprising:

a battery;

at least one sensor configured to measure at least one of a terminal voltage, a terminal current, and a temperature of the battery; and

a computing device in communication with the at least one sensor and configured to estimate a first diffusion voltage value of the battery by selecting the first diffusion voltage value from a look-up table, estimate a second diffusion voltage value of the battery using an estimation procedure, select at least one of the estimated first and second diffusion voltage values, and determine an open circuit voltage of the battery based at least in part on the selected diffusion voltage value.

13. A vehicle as set forth in claim 12, wherein the computing device is configured to derive an accumulated charge from the measured terminal current.

14. A vehicle as set forth in claim 13, wherein the computing device is configured to select the first diffusion voltage value from the look-up table based at least in part on one or more of the terminal voltage, the accumulated charge, and the temperature during the first procedure.

15. A vehicle as set forth in claim 13, wherein the computing device is configured to estimate a first set of parameter values associated with a state of health of the battery and calculate a double layer voltage based at least in part on the estimated parameter values.

16. A vehicle as set forth in claim 15, wherein the computing device is configured to determine a change in an open circuit voltage of the battery over time and estimate a second set of parameter values associated with the state of health of the battery.

17. A vehicle as set forth in claim 16, wherein the computing device is configured to estimate the second diffusion voltage value based at least in part on one or more of the terminal voltage, the accumulated charge, the double layer voltage, the change in the open circuit voltage, the first set of parameter values, and the second set of parameter values.

18. A vehicle as set forth in claim 13, wherein the computing device is configured to determine the open circuit voltage based at least in part on the selected diffusion voltage value and one or more of the terminal voltage, the accumulated charge, and the temperature.

19. A non-transitory computer-readable medium tangibly embodying computer-executable instructions comprising:

estimating a first diffusion voltage value of a battery by selecting the first diffusion voltage value from a look-up table;

estimating a second diffusion voltage value of the battery using an estimation procedure;

selecting at least one of the estimated first and second diffusion voltage values; and

determining an open circuit voltage of the battery based at least in part on the selected diffusion voltage value.

20. A non-transitory computer-readable medium tangibly embodying computer-executable instructions as set forth in claim 19, further comprising:

determining at least one of a terminal voltage, an accumulated charge, and a temperature of the battery;

wherein estimating the first diffusion voltage value includes selecting the first diffusion voltage value from the look-up table based at least in part on one or more of the terminal voltage, the accumulated charge, and the temperature; and

wherein the estimation procedure includes estimating a first set of parameter values associated with a state of health of the battery, calculating a double layer voltage based at least in part on the estimated parameter values, determining a change in an open circuit voltage of the battery over time, estimating a second set of parameter values associated with the state of health of the battery, and estimating the second diffusion voltage value based at least in part on one or more of the terminal voltage, the accumulated charge, the double layer voltage, the change in the open circuit voltage, the first set of parameter values, and the second set of parameter values.