USING REFERENCE ELECTRODES TO MANAGE BATTERIES FOR PORTABLE ELECTRONIC DEVICES

• US 20130009604A1
• Filed: 07/06/2011
• Published: 01/10/2013
• Est. Priority Date: 07/06/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bhardwaj, Ramesh C., Devan, Sheba, Hwang, Taisup, Mank, Richard M.
• Granted Patent: US 9,698,451 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The disclosed embodiments provide a system that manages use of a battery in a portable electronic device. During operation, the system uses a reference electrode in the battery to monitor an anode potential of an anode in the battery during charging of the battery in the portable electronic device. If the anode potential falls below an anode potential threshold, the system modifies a charging technique for the battery to extend a cycle life of the battery. For example, the system may reduce a charge current of the battery if the anode potential falls below the anode potential threshold to prevent degradation caused by a negative anode potential during charging of the battery.

Claims

1. A computer-implemented method for managing use of a battery in a portable electronic device, comprising:

using a reference electrode in the battery to monitor an anode potential of an anode in the battery during charging of the battery in the portable electronic device; and

if the anode potential falls below an anode potential threshold, modifying a charging technique for the battery to extend a cycle life of the battery.

2. The computer-implemented method of claim 1, further comprising:

using the reference electrode to monitor the anode potential and a cathode potential of a cathode in the battery during use of the battery with the portable electronic device; and

using the anode potential and the cathode potential to assess a state-of-health of the battery.

3. The computer-implemented method of claim 2, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery involves at least one of:

analyzing a fault in the battery;

assessing an electrode balance of the anode and the cathode; and

detecting degradation in the battery.

4. The computer-implemented method of claim 3, wherein assessing the electrode balance of the anode and the cathode involves:

comparing a first rate of change of the anode potential with a second rate of change of the cathode potential,

wherein the anode and the cathode are balanced if the first rate of change is comparable to the second rate of change at the end of discharging of the battery cell, and

wherein the anode and the cathode are imbalanced if the first rate of change is significantly different from the second rate of change at the end of the discharging of the battery cell.

5. The computer-implemented method of claim 2, further comprising:

using the assessed state-of-health to further modify the charging technique for the battery.

6. The computer-implemented method of claim 1, wherein modifying the charging technique to extend the cycle life of the battery involves:

reducing a charge current of the battery if the anode potential falls below the anode potential threshold.

7. The computer-implemented method of claim 1, wherein the anode potential threshold is 0.0V.

8. A method for facilitating the use of a battery with a portable electronic device, comprising:

obtaining a battery cell for the battery, wherein the battery cell comprises layers which are wound together, including a cathode with an active coating, a separator, an anode with an active coating, and a reference electrode;

using the reference electrode to assess an electrode balance of the battery cell; and

updating a design of the battery based on the assessed electrode balance.

9. The method of claim 8, wherein using the reference electrode to assess the electrode balance of the battery cell involves:

using the reference electrode to monitor an anode potential of the anode and a cathode potential of the cathode during discharging of the battery cell; and

comparing a first rate of change of the anode potential with a second rate of change of the cathode potential.

10. The method of claim 9,

wherein the battery cell is balanced if the first rate of change is comparable to the second rate of change at the end of the discharging of the battery cell, and

wherein the battery cell is imbalanced if the first rate of change is significantly higher than the second rate of change at the end of the discharging of the battery cell.

11. The method of claim 10, wherein updating the design of the battery based on the assessed electrode balance involves:

if the battery cell is imbalanced, increasing an amount of anode active material in the design of the battery.

12. The method of claim 8, wherein the reference electrode comprises:

a nickel tab; and

a lithium strip disposed around the nickel tab.

13. The method of claim 8, wherein the reference electrode is placed at a center of the layers or at a periphery of the layers.

14. A system for managing use of a battery in a portable electronic device, comprising:

a monitoring apparatus configured to use a reference electrode in the battery to monitor an anode potential of an anode in the battery during charging of the battery in the portable electronic device; and

a management apparatus configured to modify a charging technique for the battery to extend a cycle life of the battery if the anode potential falls below an anode potential threshold.

15. The system of claim 14,

wherein the monitoring apparatus is further configured to use the reference electrode to monitor the anode potential and a cathode potential of a cathode in the battery during use of the battery with the portable electronic device, and

wherein the management apparatus is further configured to use the anode potential and the cathode potential to assess a state-of-health of the battery.

16. The system of claim 15, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery involves at least one of:

analyzing a fault in the battery;

assessing an electrode balance of the anode and the cathode; and

detecting degradation in the battery.

17. The system of claim 16, wherein assessing the electrode balance of the anode and the cathode involves:

comparing a first rate of change of the anode potential with a second rate of change of the cathode potential,

wherein the anode and the cathode are balanced if the first rate of change is comparable to the second rate of change at the end of discharging of the battery cell, and

wherein the anode and the cathode are imbalanced if the first rate of change is significantly different from the second rate of change at the end of the discharging of the battery cell.

18. The system of claim 15, wherein the management apparatus is further configured to use the assessed state-of-health to modify the charging technique for the battery.

19. The system of claim 14, wherein modifying the charging technique to extend the cycle life of the battery involves:

reducing a charge current of the battery if the anode potential falls below the anode potential threshold.

20. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for managing use of a battery in a portable electronic device, the method comprising:

using a reference electrode in the battery to monitor an anode potential of an anode in the battery during charging of the battery in the portable electronic device; and

if the anode potential falls below an anode potential threshold, modifying a charging technique for the battery to extend a cycle life of the battery.

21. The computer-readable storage medium of claim 20, the method further comprising:

using the reference electrode to monitor the anode potential and a cathode potential of a cathode in the battery during use of the battery with the portable electronic device; and

using the anode potential and the cathode potential to assess a state-of-health of the battery.

22. The computer-readable storage medium of claim 21, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery involves at least one of:

analyzing a fault in the battery;

assessing an electrode balance of the anode and the cathode; and

detecting degradation in the battery.

23. The computer-readable storage medium of claim 22, wherein assessing the electrode balance of the anode and the cathode involves:

comparing a first rate of change of the anode potential with a second rate of change of the cathode potential,

wherein the anode and the cathode are balanced if the first rate of change is comparable to the second rate of change at the end of discharging of the battery cell, and

wherein the anode and the cathode are imbalanced if the first rate of change is significantly different from the second rate of change at the end of the discharging of the battery cell.

24. The computer-readable storage medium of claim 20, wherein modifying the charging technique to extend the cycle life of the battery involves:

reducing a charge current of the battery if the anode potential falls below the anode potential threshold.

25. A portable electronic device, comprising:

a set of components powered by a battery;

a monitoring apparatus configured to use a reference electrode in the battery to monitor an anode potential of an anode in the battery during charging of the battery in the portable electronic device; and

a management apparatus configured to modify a charging technique for the battery to extend a cycle life of the battery if the anode potential falls below an anode potential threshold.

26. The portable electronic device of claim 25,

wherein the monitoring apparatus is further configured to use the reference electrode to monitor the anode potential and a cathode potential of a cathode in the battery during use of the battery with the portable electronic device, and

wherein the management apparatus is further configured to use the anode potential and the cathode potential to assess a state-of-health of the battery.

27. The portable electronic device of claim 26, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery involves at least one of:

analyzing a fault in the battery;

assessing an electrode balance of the anode and the cathode; and

detecting degradation in the battery.

28. The portable electronic device of claim 27, wherein assessing the electrode balance of the anode and the cathode involves:

comparing a first rate of change of the anode potential with a second rate of change of the cathode potential,

wherein the anode and the cathode are balanced if the first rate of change is comparable to the second rate of change at the end of discharging of the battery cell, and

wherein the anode and the cathode are imbalanced if the first rate of change is significantly different from the second rate of change at the end of the discharging of the battery cell.

29. The portable electronic device of claim 26, wherein the management apparatus is further configured to use the assessed state-of-health to modify the charging technique for the battery.

30. The portable electronic device of claim 25, wherein modifying the charging technique to extend the cycle life of the battery involves:

reducing a charge current of the battery if the anode potential falls below the anode potential threshold.