Management of high-voltage lithium-polymer batteries in portable electronic devices

• US 9,912,186 B2
• Filed: 08/18/2016
• Issued: 03/06/2018
• Est. Priority Date: 08/25/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Dai, Hongli, Mank, Richard M.
• Primary Examiner(s): Henze-Gongola, David V
• Application Number:
  US15/240,444
• Publication Number:
  US 20160372943A1
• Time in Patent Office: 565 Days
• Field of Search: 320153, 320134, 320150
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

The disclosed embodiments provide a system that manages use of a battery corresponding to a high-voltage lithium-polymer battery in a portable electronic device. During operation, the system monitors a cycle number of the battery during use of the battery with the portable electronic device, wherein the cycle number corresponds to a number of charge-discharge cycles of the battery. If the cycle number exceeds one or more cycle number thresholds, the system modifies a charging technique for the battery to manage swelling in the battery and use of the battery with the portable electronic device.

Claims

1. An electronic system, the electronic system comprising:

at least one battery cell, the battery cell having a charge voltage;

at least one controller coupled to the battery cell, the controller configured to;

monitor a cycle number of the battery cell, the cycle number corresponding to a number of charge-discharge cycles of the battery cell;

monitor a temperature of the battery cell;

monitor a state-of-charge of the battery cell;

reduce the charge voltage applied to the battery cell when the temperature of the battery cell exceeds a temperature threshold and the cycle number exceeds a first cycle number threshold;

reduce the charge voltage applied to the battery cell when the temperature of the battery cell does not exceed the temperature threshold and the cycle number exceeds a second cycle number threshold different from the first cycle number threshold; and

cause charging of the battery cell to cease when the state-of-charge of the battery cell is a fully charged state for a time period exceeding a time threshold.

2. The electronic system of claim 1, wherein the temperature threshold is 45 degrees Celsius.

3. The electronic system of claim 1, wherein the controller is further configured to cause resumption of charging when the state-of-charge of the battery cell is less than or equal to 95 percent of the fully charged state.

4. The electronic system of claim 1, wherein the controller is a microcontroller.

5. The electronic system of claim 1, wherein the time threshold is 24 hours.

6. The electronic system of claim 1, wherein the first cycle number threshold is 300 charge-discharge cycles or 600 charge-discharge cycles.

7. The electronic system of claim 1, wherein the charge voltage is reduced by an increment after a predetermined number of charge-discharge cycles or every time the battery cell exceeds the temperature threshold.

8. The electronic system of claim 7, wherein the increment is between 10 mV and 50 mV, the predetermined number of charge-discharge cycles is 300, and the temperature threshold is 45°

C.

9. A non-transitory computer readable storage medium storing instructions executable by a controller, the instructions comprising instructions to cause the controller to:

monitor a cycle number of a battery cell, the cycle number corresponding to a number of charge-discharge cycles of the battery cell, the battery cell having a charge voltage;

monitor a temperature of the battery cell;

monitor a state-of-charge of the battery cell;

reduce the charge voltage applied to the battery cell when the temperature of the battery cell exceeds a temperature threshold and the cycle number exceeds a first cycle number threshold;

reduce the charge voltage applied to the battery cell when the temperature of the battery cell does not exceed the temperature threshold and the cycle number exceeds a second cycle number threshold different from the first cycle number threshold; and

cause charging of the battery cell to cease when the state-of-charge of the battery cell is a fully charged state for a time period exceeding a time threshold.

10. The non-transitory computer readable storage medium of claim 9, wherein the temperature threshold is 45 degrees Celsius.

11. The non-transitory computer readable storage medium of claim 9, wherein the instructions further comprise instructions to cause the controller to cause resumption of charging when the state-of-charge of the battery cell is less than or equal to 95 percent of the fully charged state.

12. The non-transitory computer readable storage medium of claim 9, wherein the time threshold is 24 hours.

13. The non-transitory computer readable storage medium of claim 9, wherein the first cycle number threshold is 300 charge-discharge cycles or 600 charge-discharge cycles.

14. The non-transitory computer readable storage medium of claim 9, wherein the instructions to reduce the charge voltage of the battery cell reduce the charge voltage by an increment after a predetermined number of charge-discharge cycles or every time the battery cell exceeds the temperature threshold.

15. The non-transitory computer readable storage medium of claim 14, wherein the increment is between 10 mV and 50 mV, the predetermined number of charge-discharge cycles is 300, and the temperature threshold is 45°

C.

16. A method of monitoring a battery cell, the method comprising:

monitoring, by at least one monitor, a cycle number of at least one battery cell, the cycle number corresponding to a number of charge-discharge cycles of the at least one battery cell, the at least one battery cell having a charge voltage;

monitoring, by the monitor, a temperature of the at least one battery cell;

monitoring, by the monitor, a state-of-charge of the at least one battery cell;

reducing the charge voltage applied to the battery cell when the temperature of the at least one battery cell exceeds a temperature threshold and the cycle number exceeds a first cycle number threshold;

reducing the charge voltage applied to the at least one battery cell when the temperature of the at least one battery cell does not exceed the temperature threshold and the cycle number exceeds a second cycle number threshold different from the first cycle number threshold; and

causing, under control of the controller, the charging of the at least one battery cell to cease when the state-of-charge of the at least one battery cell is a fully charged state for a time period exceeding a time threshold.

17. The method of claim 16, wherein the temperature threshold is 45 degrees Celsius.

18. The method of claim 16, wherein the time threshold is 24 hours.

19. The method of claim 16, wherein the first cycle number threshold is 300 charge-discharge cycles or 600 charge-discharge cycles.

20. The method of claim 16, wherein reducing the charge voltage applied to the at least one battery cell comprises reducing the charge voltage by an increment after a predetermined number of charge-discharge cycles or every time the battery cell exceeds the temperature threshold, wherein the increment is between 10 mV and 50 mV, the predetermined number of charge-discharge cycles is 300, and the temperature threshold is 45°

C.