Determination of battery predictive power limits

• US 20080007224A1
• Filed: 06/16/2006
• Published: 01/10/2008
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: Chevron Technology Ventures LLC (Chevron Corp.)
• Original Assignee: Cobasys LLC (Robert Bosch GmbH)
• Inventors: Melichar, Robert J.
• Granted Patent: US 8,466,684 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• 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 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery control module for use with a battery includes a voltage measuring module that measures battery voltage and a current measuring module that measures battery current. A power limit module communicates with the current and voltage measuring modules and once every time period estimates a battery current limit that corresponds with a future time period. The battery current limit is based on a predetermined voltage limit of the battery and a battery current and a battery voltage that correspond with a time period that precedes the future time period.

Claims

1. A battery control module for use with a battery, comprising:

a voltage measuring module that measures battery voltage;

a current measuring module that measures battery current; and

a power limit module that communicates with the current and voltage measuring modules and that once every time period estimates a battery current limit that corresponds with a future time period, wherein the battery current limit is based on a predetermined voltage limit of the battery and a battery current and a battery voltage that correspond with a time period that precedes the future time period.

2. The battery control module of claim 1 wherein the power limit module periodically estimates a power limit based on the battery current limit.

3. The battery control module of claim 1 wherein the power limit module estimates a polarization voltage of the battery and estimates the battery current limit further based on the polarization voltage.

4. The battery control module of claim 3 wherein the power limit module initializes the polarization voltage to a predetermined value.

5. The battery control module of claim 3 wherein the power limit module estimates the polarization voltage and the battery current limit once every time period.

6. A hybrid power supply system for a load, comprising:

a first power source that provides power to the load based on a power demand signal;

a rechargeable battery that provides power to the load; and

a control module in communication with the rechargeable battery, comprising;

a voltage measuring module that measures battery voltage;

a current measuring module that measures battery current; and

a power limit module that communicates with the current and voltage measuring modules,

wherein the power limit module estimates a battery current limit based on the battery current, the battery voltage, and a predetermined voltage limit of the battery, and

wherein the power limit module generates the power demand signal based on the battery current limit.

7. The hybrid power supply system of claim 6 wherein the power limit module estimates a power limit based on the battery current limit.

8. The hybrid power supply system of claim 6 wherein the power limit module estimates the battery current limit further based on a polarization voltage of the rechargeable battery.

9. The hybrid power supply system of claim 6 wherein the first power source includes an internal combustion engine.

10. The hybrid power supply system of claim 6 wherein the first power source includes an electrical power supply.

11. The battery control module of claim 6 where the rechargeable battery includes a nickel-metal hydride battery.

12. A method for controlling current draw from a battery, comprising:

measuring a battery voltage;

measuring a battery current; and

periodically estimating a battery current limit that corresponds with a future time period and represents a maximum allowable battery current through the battery, wherein the battery current limit is based on the measured battery current, the measured battery voltage, and a predetermined voltage limit of the battery.

13. The method of claim 12 further comprising estimating a maximum power that the battery can deliver based on the predicted battery current limit.

14. The method of claim 12 wherein the battery current limit is further based on a polarization voltage of the battery.

15. A method for controlling a hybrid power supply system, comprising:

operating a first power source to provide power to a load based on a power demand signal;

supplying power to the load from a rechargeable battery;

measuring a battery voltage of the rechargeable battery;

measuring a battery current of the rechargeable battery;

periodically estimating a battery current limit that corresponds with a future time period and represents a maximum allowable battery current through the battery; and

generating the power demand signal based on the estimated battery current limit, wherein the battery current limit is based on the measured battery current, the measured battery voltage, and a predetermined voltage limit of the battery

16. The method of claim 15 further comprising estimating a maximum power of the battery based on the estimated battery current limit.

17. The method of claim 15 wherein the battery current limit is further based on a polarization voltage of the battery.

18. The method of claim 17 further comprising initializing the polarization voltage to a predetermined value.

19. The method of claim 17 wherein the power limit module estimates the polarization voltage and the battery current limit once every time period.

20. The method of claim 15 wherein the first power source includes an internal combustion engine.

21. The method of claim 15 wherein the first power source includes an electrical power supply.

22. The method of claim 15 wherein the rechargeable battery includes a nickel-metal hydride battery.

23. A powertrain system for a hybrid electric vehicle, comprising:

a rechargeable battery that provides power to an electric motor for propelling the vehicle;

an internal combustion engine that generates power for propelling the vehicle;

an engine controller that starts the internal combustion engine in response to a power demand signal; and

a control module in communication with the rechargeable battery, comprising;

a voltage measuring module that measures battery voltage;

a current measuring module that measures battery current; and

a power limit module that communicates with the current and voltage measuring modules,

wherein the power limit module periodically determines a battery current limit corresponding to a future period and based on the battery current and the battery voltage; and

wherein the power limit module generates the power demand signal based on the battery current limit such that the engine controller starts the internal combustion engine prior to the future period.

24. The powertrain system of claim 23 wherein the power limit module determines a power limit based on the battery current limit.