METHOD AND SYSTEM FOR REPORTING BATTERY STATUS BASED ON CURRENT ESTIMATION

• US 20090132186A1
• Filed: 10/31/2008
• Published: 05/21/2009
• Est. Priority Date: 11/15/2007
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Sanyal, Sumit, Esnard, Domitille, Walley, John
• Application Number:
  US12/262,527
• Publication Number:
  US 20090132186A1
• 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 31/3828 using current integration
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

A charge stored in a battery is estimated by multiplying estimated charge currents supplied during charge phases and estimated discharge currents discharged during operational modes by the respective amounts of time of charging and discharge. The state of charge of the battery is calculated from the estimated stored charge. Furthermore, parameters of the battery may be measured to be used to adjust the estimated state of charge of the battery. In a first case, the estimated stored charge may be adjusted to a charge value corresponding to the detected completion of a constant current charge phase. In a second case, the estimated stored charge may be adjusted to a charge value corresponding to the detected completion of a constant voltage charge phase. In a third case, the estimated stored charge may be adjusted to a charge value corresponding to a detected predetermined discharge level of the battery.

Claims

1. A method for estimating a state of charge for a rechargeable battery of an electronic device, comprising:

calculating a first increase in a charge stored in the battery during a first charge phase of the battery in which a substantially constant charge current is received by the battery for a first amount of time;

calculating a second increase in the charge stored in the battery during a second charge phase of the battery in which a decreasing charge current is received by the battery for a second amount of time;

calculating a reduction of the charge stored in the battery by multiplying a predetermined discharge current corresponding to an operational mode of the electronic device by an amount of time that the electronic device is in the operational mode;

calculating a stored charge in the battery based on a prior determined stored charge in the battery and at least one of the calculated reduction in the charge, the calculated first increase in the charge, or the calculated second increase in the charge; and

calculating a state of charge of the battery based on the calculated stored charge.

2. The method of claim 1, further comprising:

measuring a parameter of the battery; and

adjusting the calculated state of charge of the battery according to the measured parameter.

3. The method of claim 2, wherein said measuring comprises:

measuring a voltage and/or current of the battery to determine a completion of the first charge phase; and

wherein said adjusting comprises;

adjusting the calculated stored charge to a charge value corresponding to the completion of the first charge phase, and

calculating the state of charge of the battery based on the adjusted stored charge.

4. The method of claim 2, wherein said measuring comprises:

measuring a current of the battery to determine a completion of the second charge phase; and

wherein said adjusting comprises;

adjusting the calculated stored charge to a charge value corresponding to the completion of the second charge phase, and

calculating the state of charge of the battery based on the adjusted stored charge.

5. The method of claim 2, wherein said measuring comprises:

measuring a voltage of the battery to determine whether the battery is discharged to a predetermined amount of stored charge; and

wherein said adjusting comprises;

adjusting the calculated stored charge to the predetermined amount of stored charge, and

calculating the state of charge of the battery based on the adjusted stored charge.

6. The method of claim 1, wherein said calculating the state of charge of the battery based on the calculated stored charge comprises:

calculating the state of charge (SOC) of the battery as a percentage according to

SOC of the battery=100×

CSC/SOH,

where

SOH=a state of charge of the battery, and

CSC=the calculated stored charge.

7. The method of claim 1, further comprising:

displaying the calculated state of charge of the battery.

8. A battery manager, comprising:

a first charge phase charge calculator configured to calculate a first increase in a charge stored in the battery during a first charge phase of the battery in which a substantially constant charge current is received by the battery for a first amount of time;

a second charge phase charge calculator configured to calculate a second increase in the charge stored in the battery during a second charge phase of the battery in which a decreasing charge current is received by the battery for a second amount of time;

a third charge phase charge calculator configured to calculate a reduction of the charge stored in the battery by multiplying a predetermined discharge current corresponding to an operational mode of the electronic device by an amount of time that the electronic device is in the operational mode;

a summer configured to calculate a stored charge in the battery based on a prior determined stored charge in the battery and at least one of the calculated reduction in the charge, the calculated first increase in the charge, or the calculated second increase in the charge; and

a state of charge calculator configured to calculate the state of charge of the battery based on the calculated stored charge.

9. The battery manager of claim 8, further comprising:

a stored charge adjuster configured to measure a parameter of the battery, and to calculate an adjusted stored charge for the battery according to the measured parameter.

10. The battery manager of claim 9, wherein the stored charge adjuster comprises:

a beacon point detector configured to measure a voltage and/or current of the battery to determine a completion of the first charge phase, and to adjust the calculated stored charge to a charge value corresponding to the completion of the first charge phase.

11. The battery manager of claim 9, wherein the stored charge adjuster comprises:

a beacon point detector configured to measure a current of the battery to determine a completion of the second charge phase, and to adjust the calculated stored charge to a charge value corresponding to the completion of the second charge phase.

12. The battery manager of claim 9, wherein the stored charge adjuster comprises:

a beacon point detector configured to measure a voltage of the battery to determine whether the battery is discharged to a predetermined amount of stored charge, and to adjust the calculated stored charge to the predetermined amount of stored charge.

13. The system of claim 8, wherein the battery is a lithium battery.

14. The system of claim 8, further comprising:

an indicator configured to display the calculated state of charge.

15. A method for tracking a state of charge of a rechargeable battery of an electronic device, comprising:

estimating the state of charge of the battery;

measuring a parameter of the battery; and

adjusting the estimated state of charge of the battery according to the measured parameter.

16. The method of claim 15, wherein said measuring comprises:

measuring a voltage and/or current of the battery to determine a completion of a constant current charge phase for the battery; and

wherein said adjusting comprises;

adjusting a stored charge determined for the battery to a charge value corresponding to the completion of the constant current charge phase, and

calculating the state of charge of the battery based on the adjusted stored charge.

17. The method of claim 15, wherein said measuring comprises:

measuring a current of the battery to determine a completion of a constant voltage charge phase for the battery; and

wherein said adjusting comprises;

adjusting a stored charge determined for the battery to a charge value corresponding to the completion of the constant voltage charge phase, and

calculating the state of charge of the battery based on the adjusted stored charge.

18. The method of claim 15, wherein said measuring comprises:

measuring a voltage of the battery to determine whether the battery is discharged to a predetermined amount of stored charge; and

wherein said adjusting comprises;

adjusting a stored charge determined for the battery to the predetermined amount of stored charge, and

calculating the state of charge of the battery based on the adjusted stored charge.

19. The method of claim 15, further comprising:

displaying the calculated state of charge of the battery.

20. A battery-powered electrical device, comprising:

a battery manager that includes a battery charger, a timer, and a stored charge estimator configured to estimate a state of charge of a battery; and

a battery port configured to interface the battery with the device;

wherein the stored charge estimator includes

a first charge phase charge calculator configured to calculate a first increase in a charge stored in the battery during a first charge phase of the battery in which a substantially constant charge current is received by the battery for a first amount of time;

a second charge phase charge back later configured to calculate a second increase in the charge stored in the battery during a second charge phase of the battery in which a decreasing charge current is received by the battery for a second amount of time;

a third charge phase charge calculator configured to calculate a reduction of the charge stored in the battery by multiplying a predetermined discharge current corresponding to an operational mode of the electronic device by an amount of time that the electronic device is in the operational mode;

a summer configured to calculate a stored charge in the battery based on a prior determined stored charge in the battery and at least one of the calculated reduction in the charge, the calculated first increase in the charge, or the calculated second increase in the charge; and

a state of charge calculator configured to calculate the state of charge of the battery based on the calculated stored charge.

21. The battery-powered electrical device of claim 20, wherein the battery manager further includes:

a stored charge adjuster configured to measure a parameter of the battery, and to calculate an adjusted stored charge for the battery according to the measured parameter.