Method and system for tracking battery state-of-health based on charging information

• US 8,258,751 B2
• Filed: 01/23/2008
• Issued: 09/04/2012
• Est. Priority Date: 11/15/2007
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Esnard, Domitille
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US12/018,425
• Publication Number:
  US 20090128097A1
• Time in Patent Office: 1,686 Days
• Field of Search: 320/132
• 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 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/488 Cells or batteries combined with indicating means for external visualization of the condition, e.g. by change of colour or of light density
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Methods, systems, and apparatuses for determining battery state of health are provided. A battery that is substantially uncharged is charged with a substantially constant charge current. A time duration of the charging of the battery with the substantially constant charge current is determined. A state of health of the battery is estimated based upon the determined time duration and the constant charge current. The state of health of the battery may be calculated by multiplying the determined time duration with a value of the constant charge current to determine a total accumulated charge, and applying a predetermined factor to the accumulated charge to determine the state of health. The predetermined factor is a fixed percentage of the total charge capacity of the battery that corresponds to the battery type.

Claims

1. A method for determining battery state of health, comprising:

receiving a battery that is substantially uncharged;

charging the battery during a first charge phase during which the battery is charged with a substantially constant charge current and during a second charge phase during which a substantially constant voltage is applied to the battery;

measuring a time duration of the first charge phase only; and

calculating a state of health of the battery based upon the measured time duration and the constant charge current.

2. The method of claim 1, wherein said calculating comprises:

calculating the state of health (SOH) of the battery according to

SOH of the battery=TD×

CCC/FPTC,

where

TD=the measured time duration,

CCC=the constant charge current, and

FPTC=a predetermined fixed percentage of a total charge capacity of the battery.

3. The method of claim 2, wherein the battery is a lithium battery.

4. The method of claim 1, further comprising:

displaying the calculated state of health of the battery.

5. The method of claim 1, further comprising:

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

6. The method of claim 5, further comprising:

displaying the calculated state of charge of the battery.

7. A system for determining battery health, comprising:

a battery charger configured to charge a battery from a substantially uncharged state during a first charge phase during which the battery is charged with a substantially constant charge current and during a second charge phase during which a substantially constant voltage is applied to the battery;

a charge timer configured to measure a time duration of the first charge phase only; and

a battery state of health calculator configured to calculate a state of health of the battery based upon the measured time duration and the constant charge current.

8. The system of claim 7, wherein the battery state of health calculator is configured to calculate the state of health (SOH) of the battery according to

SOH of the battery=TD×

CCC/FPTC,

where

TD=the measured time duration,

CCC=the constant charge current, and

FPTC=a predetermined fixed percentage of a total charge capacity of the battery.

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

10. The system of claim 8, further comprising:

an indicator configured to display the calculated state of health.

11. The system of claim 7, further comprising:

a battery state of charge calculator configured to calculate a state of charge of the battery based upon the calculated state of health.

12. The system of claim 11, further comprising:

an indicator configured to display the calculated state of charge.

19. The system of claim 8, wherein the FPTC has a value that does not vary substantially with battery age and is substantially constant for a particular charge current and temperature range.

13. A battery-powered electrical device, comprising:

a battery monitor that includes a battery charger, a charge timer, and a battery state of health calculator; and

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

wherein the battery charger is configured to charge the interfaced battery from a substantially uncharged state during a first charge phase during which the battery is charged with a substantially constant charge current and during a second charge phase during which a substantially constant voltage is applied to the battery;

wherein the charge timer is configured to measure a time duration of the first charge phase only; and

wherein the battery state of health calculator is configured to calculate a state of health of the battery based upon the measured time duration and the constant charge current.

14. The device of claim 13, wherein the battery state of health calculator is configured to calculate the state of health (SOH) of the battery according to

SOH of the battery=TD×

CCC/FPTC,

where

TD=the measured time duration,

CCC=the constant charge current, and

FPTC=a predetermined fixed percentage of a total charge capacity of the battery.

15. The device of claim 14, wherein the battery is a lithium battery.

16. The device of claim 13, further comprising

a battery state of health indicator configured to provide an indication of the calculated state of health of the battery.

17. The device of claim 16, wherein the battery state of health indicator includes at least one light emitting diode.

18. The device of claim 16, further comprising:

a display;

wherein the battery state of health indicator comprises a graphical icon displayed by the display.

20. The device of claim 14, wherein the FPTC has a value that does not vary substantially with battery age and is substantially constant for a particular charge current and temperature range.