Battery state of charge voltage hysteresis estimator

• US 20060091863A1
• Filed: 12/13/2005
• Published: 05/04/2006
• Est. Priority Date: 04/06/2004
• 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 7,570,024 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/387 Determining ampere-hour charge capacity or SoC
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

A battery control module is provided for use with a battery and includes a voltage measuring module that measures battery voltage, a current measuring module that measures battery current, and a state of charge (SOC) module that communicates with said current and voltage measuring modules. In some features, the SOC module determines an unfiltered SOC of said battery, a characteristic of said unfiltered SOC, and a modified SOC that is based on said unfiltered SOC and said characteristic. In other features, the SOC module determines first and second reset voltages, compares the battery voltage to the first and second reset voltages, and determines an unfiltered SOC based on said first and second reset voltages and said battery voltage.

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 state of charge (SOC) module that communicates with said current and voltage measuring modules and determines an unfiltered SOC of said battery, a characteristic of said unfiltered SOC, and a modified SOC that is based on said unfiltered SOC and said characteristic.

2. The battery control module of claim 1 wherein said characteristic includes a rate of change.

3. The battery control module of claim 1 wherein said characteristic includes a direction.

4. The battery control module of claim 1 wherein said SOC module further determines a first filtered SOC based on said unfiltered SOC and determines said characteristic based on said first filtered SOC.

5. The battery control module of claim 4 wherein said SOC module further determines a second filtered SOC based on said unfiltered SOC and determines said characteristic based on said first filtered SOC and said second filtered SOC.

6. 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 state of charge (SOC) module that determines first and second reset voltages, compares the battery voltage to the first and second reset voltages, and determines an unfiltered SOC based on said first and second reset voltages and said battery voltage.

7. The battery control module of claim 6 wherein said SOC module maintains running averages of said first and second reset voltages and said battery voltage;

and

wherein said SOC module determines said unfiltered SOC based on said running averages.

8. The battery control module of claim 7 wherein said SOC module determines said unfiltered SOC based on the equation

SOC=socLow+(socHigh−

socLow)*(vAvg−

hLowAvg)/(hHighAvg−

hLowAvg),

where socLow is a SOC value that corresponds to a most recent value of the first reset voltage, socHigh is a SOC value that corresponds to a most recent value of the second reset voltage, Vavg is the running average of the battery voltage, and HLowAvg and hHighAvg are running averages of the respective first and second reset voltages.

9. A method for determining a state-of-charge (SOC) of a battery, comprising:

measuring a battery voltage;

measuring a battery current;

determining an unfiltered SOC of said battery;

determining a characteristic of said unfiltered SOC; and

determining a modified SOC that is based on said unfiltered SOC and said characteristic.

10. The method of claim 9 wherein said characteristic includes a rate of change.

11. The method of claim 9 wherein said characteristic includes a direction.

12. The method of claim 9 further comprising:

determining a first filtered SOC based on said unfiltered SOC; and

determining said characteristic based on said first filtered SOC.

13. The method of claim 12 further comprising:

determining a second filtered SOC based on said unfiltered SOC; and

determining said characteristic based on said first filtered SOC and said second filtered SOC.

14. A method for determining a state-of-charge (SOC) of a battery, comprising:

measuring a battery voltage;

measuring a battery current;

determining first and second reset voltages;

comparing the battery voltage to the first and second reset voltages; and

determining said unfiltered SOC based on said first and second reset voltages and said battery voltage.

15. The method of claim 14 further comprising:

maintaining a running average of said first reset voltage;

maintaining a running average of said second reset voltage;

maintaining a running average of said battery voltage; and

determining said unfiltered SOC based on said running averages of said first reset voltage, said second reset voltage, and said battery voltage.

16. The method of claim 15 wherein said determining step includes the equation

SOC=socLow+(socHigh−

socLow)*(vAvg−

hLowAvg)/(hHighAvg−

hLowAvg),

where socLow is a SOC value that corresponds to a most recent value of the first reset voltage, socHigh is a SOC value that corresponds to a most recent value of the second reset voltage, Vavg is the running average of the battery voltage, and HLowAvg and hHighAvg are running averages of the respective first and second reset voltages.

18. The battery control module of claim 15 wherein said characteristic includes a rate of change.

19. The battery control module of claim 15 wherein said characteristic includes a direction.

20. The battery control module of claim 15 wherein said SOC determining means further determines a first filtered SOC based on said unfiltered SOC and determines said characteristic based on said first filtered SOC.

21. The battery control module of claim 18 wherein said SOC determining means further determines a second filtered SOC based on said unfiltered SOC and determines said characteristic based on said first filtered SOC and said second filtered SOC.

22. The battery control module of claim 15 wherein said SOC determining means further determines first and second reset voltages, compares the battery voltage to the first and second reset voltages, resets the SOC based on the comparison of the battery voltage to the first and second reset voltages, and determines said unfiltered SOC based on said first and second reset voltages and said battery voltage.

23. The battery control module of claim 20 wherein said SOC determining means maintains running averages of said first and second reset voltages and said battery voltage;

and

wherein said SOC determining means determines said unfiltered SOC based on said running averages.

24. The battery control module of claim 23 wherein said SOC determining means determines said unfiltered SOC based on the equation

SOC=socLow+(socHigh−

socLow)*(vAvg−

hLowAvg)/(hHighAvg−

hLowAvg),

where socLow is a SOC value that corresponds to a most recent value of the first reset voltage, socHigh is a SOC value that corresponds to a most recent value of the second reset voltage, Vavg is the running average of the battery voltage, and HLowAvg and hHighAvg are running averages of the respective first and second reset voltages.

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

voltage measuring means for measuring battery voltage;

current measuring means for measuring battery current; and

state of charge (SOC) determining means for communicating with said current and voltage measuring means, determining an unfiltered SOC of said battery, determining a characteristic of said unfiltered SOC, and determining a modified SOC based on said unfiltered SOC and said characteristic.