Determination of battery predictive power limits

• US 8,466,684 B2
• Filed: 06/16/2006
• Issued: 06/18/2013
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: Chevron Technology Ventures LLC (Chevron Corp.)
• Original Assignee: Chevron Technology Ventures LLC (Chevron Corp.)
• Inventors: Melichar, Robert J.
• Primary Examiner(s): RAMADAN, RAMY O
• Application Number:
  US11/455,297
• Publication Number:
  US 20080007224A1
• Time in Patent Office: 2,559 Days
• Field of Search: 320/132, 324/426, 702/63, 702/64, 702/65
• US Class Current: 324/426
• 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, the battery control module comprising:

a voltage measuring module that measures voltages of the battery;

a current measuring module that measures a battery current through the battery during a current time period; and

a power limit module that communicates with the current and voltage measuring modules and that during a future time period estimates a battery current limit, wherein the future time period is subsequent to the current time period, and wherein the power limit module iteratively estimates the battery current limit,

wherein the power limit module estimates the battery current limit during the future time period based on;

a predetermined voltage limit of the battery;

the battery current through the battery; and

a battery voltage of the battery during a time period prior to 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 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 during each of a plurality of time periods;

and

the plurality of time periods include the current time period, the future time period, and the time period prior to the future time period.

21. The battery control module of claim 1, wherein the time period prior to the future time period is one of the current time period and a time period prior to the current time period.

6. A hybrid power supply system for a load, the hybrid power supply system 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 voltages of the rechargeable battery;

a current measuring module that measures battery currents through the rechargeable battery; and

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

wherein the power limit module estimates a battery current limit during a predetermined time period based on one of the measured battery currents, a predetermined voltage limit of the rechargeable battery, and at least one of;

a running average over time of the measured battery voltages; and

one of the measured battery voltages measured during a time period prior to the predetermined time period, 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 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.

22. The hybrid power supply system of claim 6, wherein:

the power limit module estimates the battery current limit during the predetermined time period based on one of the measured battery voltages measured during the time period prior to the predetermined time period; and

the one of the measured battery voltages measured during the time period prior to the predetermined time period is a polarization voltage of the rechargeable battery.

23. The hybrid power supply system of claim 6, wherein:

the power limit module estimates the battery current limit during the predetermined time period based on the running average over time of the measured battery voltages; and

the control module determines the running average over time of the measured battery voltages based on;

a running average over time of measured battery voltages during the time period prior to the predetermined time period;

a value between zero and one; and

the battery voltage measured during the predetermined time period.

24. The hybrid power supply system of claim 6, wherein the power limit module estimates the battery current limit based on:

the one of the measured battery currents measured during the predetermined time period;

a resistance of the rechargeable battery; and

a time constant that is based on (i) one of the measured battery voltages measured during the predetermined time period, and (ii) a voltage limit of the rechargeable battery,

wherein the one of the measured battery voltages is a polarization voltage.

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

measuring battery voltages of the battery;

measuring battery currents through the battery; and

predicting a battery current limit during a predetermined time period, wherein the battery current limit represents a maximum allowable battery current through the battery,

wherein the battery current limit is based on;

one of the measured battery currents;

a predetermined voltage limit of the battery; and

at least one of;

a running average over time of the measured battery voltages; and

one of the measured battery voltages measured during a time period prior to the predetermined time period.

12. The method of claim 11 further comprising estimating a maximum power that the battery can deliver based on the battery current limit.

13. The method of claim 11 further comprising predicting the battery current limit based on a polarization voltage of the battery.

14. A method for controlling a hybrid power supply system, the method 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 battery voltages of the rechargeable battery;

measuring battery currents through the rechargeable battery;

estimating a battery current limit during a predetermined time period, wherein the battery current limit 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 estimated based on;

one of the measured battery currents;

a first one of the measured battery voltages, wherein the one of the measured battery currents and the first one of the measured battery voltages are measured during the predetermined time period,

a predetermined voltage limit of the battery, and

at least one of;

a running average over time of the measured battery voltages including the first one of the measured battery voltages measured during the predetermined time period; and

a second one of the measured battery voltages measured during a time period prior to the predetermined time period.

15. The method of claim 14 further comprising estimating a maximum power of the battery based on the estimated battery current limit.

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

17. The method of claim 16 further comprising initializing the polarization voltage to a predetermined value.

18. The method of claim 16 further comprising estimating the polarization voltage and the battery current limit during each of a plurality of time periods,

wherein the plurality of time periods include the predetermined time period and the time period prior to the predetermined time period.

19. The method of claim 14 wherein the first power source includes at least one of an internal combustion engine and an electrical power supply.

20. A powertrain system for a hybrid electric vehicle, the powertrain system 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 and comprising;

a voltage measuring module that measures a battery voltage of the rechargeable battery during a time period prior to a predetermined time period;

a current measuring module that measures a battery current through the rechargeable battery; and

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

wherein the power limit module determines a battery current limit during the predetermined 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 predetermined period.