METHOD FOR ESTIMATING BATTERY LIFE IN A HYBRID POWERTRAIN

• US 20090112495A1
• Filed: 09/18/2008
• Published: 04/30/2009
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), Daimler AG (Mercedes-Benz Group AG), GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Chrysler LLC (Stellantis NV)
• Inventors: Center, Marc B.
• Granted Patent: US 8,204,702 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

A method for estimating an operating life for an electrical energy storage system electrically connected to transmit power to a hybrid powertrain system includes monitoring temperature state-of-charge and electric current of the electrical energy storage system, calculating a battery life metric for a time interval based upon the temperature, the state-of-charge, and the electric current discharge, determining a total battery life metric therefrom and determining the remaining operating life of the electrical energy storage system.

Claims

1. A method for estimating a remaining operating life of an electrical energy storage device electrically operatively connected to an electric machine of a hybrid powertrain system, comprising:

monitoring temperature, state-of-charge, and electric current discharge of the electrical energy storage device;

determining a temperature factor and a state-of-charge factor based upon the monitored temperature and monitored state-of-charge during a predetermined time interval;

calculating a battery life metric during the predetermined time interval based upon the temperature factor, the state-of-charge factor, and the electric current discharge;

determining a total battery life metric based on the calculated battery life metric; and

determining the remaining operating life of the electrical energy storage device based upon the total battery life metric.

2. The method of claim 1, wherein the temperature factor is determined from a predetermined function based upon temperature of the electrical energy storage device at any instant of time within the predetermined time interval.

3. The method of claim 2, wherein the predetermined function comprises temperature factor increases with increasing temperature of the electrical energy storage device.

4. The method of claim 1, wherein the state-of-charge factor is determined from a predetermined function based upon the state-of-charge of the electrical energy storage device at any instant of time within the predetermined time interval.

5. The method of claim 4, wherein the predetermined function comprises a unity state-of-charge factor for states-of charge within a preferred state-of-charge range, increasing state-of-charge factor with increasing state-of-charge greater than the preferred state-of-charge range, and increasing state-of-charge factor with decreasing state-of-charge less than the preferred state-of-charge range.

6. The method of claim 1, further comprising:

determining total electric current discharge for the electrical energy storage device over the predetermined time interval.

7. The method of claim 6, wherein determining total electrical current discharge comprises:

measuring magnitudes of the electric current discharge during discharge events; and

integrating the magnitudes of the electric current discharge.

8. The method of claim 1, wherein:

the temperature factor is determined from a predetermined function based upon temperature of the electrical energy storage device at any instant of time within the predetermined time interval;

the state-of-charge factor is determined from a predetermined function based upon the state-of-charge of the electrical energy storage device at any instant of time within the predetermined time interval;

said method further comprising determining total electric current discharge for the electrical energy storage device over the predetermined time interval; and

wherein the battery life metric comprises a product of the total electric current discharge, the temperature factor, and the state-of-charge factor.

9. The method of claim 1, wherein determining the remaining operating life of the electrical energy storage device is further based upon a predetermined battery lifespan, wherein the remaining operating life is the difference between the predetermined battery lifespan and the total battery life metric.

10. The method of claim 1, wherein determining the remaining operating life of the electrical energy storage device is further based upon collected vehicle fleet data, wherein the remaining operating life is the difference between a predicted electrical energy storage device lifespan based upon the collected vehicle fleet data and the total battery life metric.

11. The method of claim 10, wherein the predicted electrical energy storage device lifespan is a lifespan at a predetermined standard deviation from a mean electrical energy storage device lifespan determined from the collected vehicle fleet data.

12. The method of claim 1, wherein determining the total battery life metric comprises cumulatively summing successively calculated battery life metrics.

13. A method for estimating a remaining operating life of an electrical energy storage device electrically connected to transmit power to an electro-mechanical transmission, comprising:

monitoring temperature of the electrical energy storage device;

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

monitoring electric current discharge of the electrical energy storage device;

determining a temperature factor and a state-of-charge factor based upon the monitored temperature and state-of-charge during a predetermined time interval;

calculating a battery life metric during the predetermined time interval based upon the temperature factor, the state-of-charge factor, and the electric current discharge;

determining a total battery life metric based on the calculated battery life metric; and

determining the remaining operating life of the electrical energy storage device based upon a predicted electrical energy storage device lifespan and the total battery life metric, wherein the remaining electrical energy storage device life is the difference between the predicted battery lifespan and the total battery life metric.

14. The method of claim 13, wherein:

said predicted electrical energy storage device lifespan is based upon collected vehicle fleet data, wherein the predicted electrical energy storage device lifespan is a lifespan at a predetermined standard deviation from a mean electrical energy storage device lifespan determined from the collected vehicle fleet data.

15. The method of claim 13, wherein determining the total battery life metric comprises cumulatively summing successively calculated battery life metrics.