Using reference electrodes to manage batteries for portable electronic devices

• US 9,698,451 B2
• Filed: 07/06/2011
• Issued: 07/04/2017
• Est. Priority Date: 07/06/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bhardwaj, Ramesh C., Hwang, Taisup, Devan, Sheba, Mank, Richard M.
• Primary Examiner(s): Berhanu, Samuel
• Application Number:
  US13/177,468
• Publication Number:
  US 20130009604A1
• Time in Patent Office: 2,190 Days
• Field of Search: 320134-136
• 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 process for managing use of a battery in a portable electronic device, the process comprising:

using a reference electrode in the battery to monitor an anode potential between the reference electrode and an anode in the battery and a cathode potential between the reference electrode and a cathode of the battery, wherein the reference electrode is not in electrical contact with the anode or the cathode; and

analyzing the anode potential and the cathode potential using a computer to assess a state of health of the battery, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery comprises assessing an electrode balance of the anode and the cathode.

2. The process of claim 1 further comprising:

when the anode potential falls below an anode potential threshold during charging of the battery, using the computer to execute instructions embodied on a non-transitory computer-readable storage medium to modify a charging technique for the battery.

3. The process of claim 2, wherein the anode potential threshold is 0.0V.

4. The process of claim 1, wherein assessing the electrode balance of the anode and the cathode comprises determining whether the anode and the cathode are balanced based on a comparison of a first rate of change of the anode potential and a second rate of change of the cathode potential.

5. The process of claim 1, further comprising:

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

6. 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 anode potential of the anode and a cathode potential of the cathode during discharging of the battery cell; and

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

7. The method of claim 6, wherein using the reference electrode to assess the anode potential and the cathode potential further comprises determining whether the anode and the cathode are balanced based on a comparison of a first rate of change of the anode potential during the discharge and a second rate of change of the cathode potential during the discharge.

8. The method of claim 7, wherein updating the design of the battery based on the assessed electrode balance comprises:

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

9. The method of claim 6, wherein the reference electrode is placed at a center of the layers or at a periphery of the layers.

10. 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 between the reference electrode and an anode in the battery and a cathode potential of a cathode of the battery, wherein the reference electrode is not in electrical contact with the anode or the cathode; and

a management apparatus configured to use the anode potential and the cathode potential to assess a state of health of the battery by assessing an electrode balance of the anode and the cathode.

11. The system of claim 10, wherein:

the management apparatus is further configured to modify a charging technique for the battery when the anode potential falls below an anode potential threshold.

12. The system of claim 10, wherein assessing the electrode balance of the anode and the cathode comprises determining whether the anode and the cathode are balanced based on a comparison of a first rate of change of the anode potential and a second rate of change of the anode potential.

13. The system of claim 10, wherein the management apparatus is further configured to use the assessed state-of-health to modify the charging technique for the battery.

14. 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 between the reference electrode and an anode in the battery and a cathode potential between the reference electrode and a cathode in the battery, wherein the reference electrode is not in electrical contact with the anode or the cathode;

using the anode potential and the cathode potential to assess a state of health of the battery, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery comprises assessing an electrode balance of the anode and the cathode.

15. The computer-readable storage medium of claim 14 wherein the method further comprises:

when the anode potential falls below an anode potential threshold, modifying a charging technique for the battery.

16. The computer-readable storage medium of claim 14, wherein assessing the electrode balance of the anode and the cathode comprises determining whether the anode and the cathode are balanced based on a comparison of a first rate of change of the anode potential and a second rate of change of the cathode potential.

17. 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 between the reference electrode and an anode in the battery and a cathode potential between the reference electrode and a cathode in the battery, wherein the reference electrode is not in electrical contact with the anode or the cathode; and

use the anode potential and the cathode potential to assess a state of health of the battery, wherein using the anode potential and the cathode potential to assess the state-of-health of the battery comprises assessing an electrode balance of the anode and the cathode.

18. The portable electronic device of claim 17 further comprising:

a management apparatus configured to modify a charging technique for the battery when the anode potential falls below an anode potential threshold.

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

20. The portable electronic device of claim 17, wherein assessing the electrode balance of the anode and the cathode comprises determining whether the anode and the cathode are balanced based on a comparison of a first rate of change of the anode potential and a second rate of change of the cathode potential.