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

• US 9,450,443 B2
• Filed: 09/23/2014
• Issued: 09/20/2016
• 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): Tso, Edward
• Assistant Examiner(s): Henze-Gongola, David V
• Application Number:
  US14/494,387
• Publication Number:
  US 20150102767A1
• Time in Patent Office: 728 Days
• Field of Search: 320/150, 320/134
• US Class Current: 1/1
• 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. A method, comprising:

at an electronic device;

monitoring a cycle number of a battery during use of the battery, the cycle number representing a number of charge-discharge cycles of the battery, the battery having a charge voltage;

monitoring a temperature of the battery during use of the battery;

in event the temperature of the battery exceeds a temperature threshold, incrementally reducing the charge voltage of the battery in event the cycle number exceeds a first cycle number threshold;

in event the temperature of the battery does not exceed the temperature threshold, incrementally reducing the charge voltage in event the cycle number exceeds a second cycle number threshold, wherein the first cycle number threshold is different than the second cycle number threshold;

monitoring a state-of-charge of the battery while charging the battery at the charge voltage; and

in event the state-of-charge of the battery is fully charged for longer than a time threshold, halting the charging of the battery.

2. The method of claim 1, further comprising reducing the charge voltage by a voltage in a range of 10 mV to 50 mV each time that the cycle number exceeds the corresponding first cycle number threshold or the second cycle number threshold.

3. The method of claim 2, further comprising reducing the charge voltage from an initial voltage value in a range of 4.2V to 5V.

4. The method of claim 2, further comprising further reducing the charge voltage based on the second cycle number threshold in event the temperature of the battery exceeds the temperature threshold.

5. The method of claim 1, further comprising:

in event the state-of-charge of the battery falls below a threshold state-of-charge, resuming charging the battery.

6. The method of claim 1, wherein the second cycle number threshold is higher than the first cycle number threshold.

7. An electronic device, comprising:

a controller; and

a monitoring circuit coupled to the controller, the monitoring circuit configured to transmit one or more parameters of a battery to the controller;

wherein the controller is configured to;

monitor a cycle number of the battery during use of the battery, the cycle number representing a number of charge-discharge cycles of the battery, the battery having a charge voltage;

monitor a temperature of the battery during use of the battery;

in event the temperature of the battery exceeds a temperature threshold, incrementally reduce the charge voltage of the battery in event the cycle number exceeds a first cycle number threshold;

in event the temperature of the battery does not exceed the temperature threshold, incrementally reduce the charge voltage of the battery in event the cycle number exceeds a second cycle number threshold, wherein the first cycle number threshold is different than the second cycle number threshold; and

monitor a state-of-charge of the battery while charging the battery at the charge voltage; and

in event the state-of-charge of the battery is fully charged for longer than a time threshold, halt the charging of the battery.

8. The electronic device of claim 7, wherein the controller is further configured to reduce the charge voltage by a voltage in a range of 10 mV to 50 mV each time that the cycle number exceeds the corresponding first cycle number threshold or second cycle number threshold.

9. The electronic device of claim 8, wherein the controller is further configured to reduce the charge voltage by a first voltage based on the first cycle number threshold and reduce the charge voltage by a second voltage based on the second cycle number threshold, wherein the first voltage is different than the second voltage.

10. The electronic device of claim 7, wherein the controller is further configured to:

resume the charging of the battery in event the state-of-charge of the battery falls below a threshold state-of-charge.

11. A non-transitory computer-readable storage medium storing computer-readable medium (CRM) instructions for execution by a controller, wherein the CRM instructions comprise instructions to:

monitor a cycle number of a battery during use of the battery, the cycle number representing a number of charge-discharge cycles of the battery, the battery having a charge voltage;

monitor a temperature of the battery during use of the battery;

modify the charge voltage for the battery by;

in event the temperature of the battery exceeds a temperature threshold, incrementally reducing the charge voltage in event the cycle number exceeds a first cycle number threshold; and

in event the temperature of the battery does not exceed the temperature threshold, incrementally reducing the charge voltage of the battery in event the cycle number exceeds a second cycle number threshold, wherein the first cycle number threshold is different than the second cycle number threshold;

monitor a state-of-charge of the battery while the battery is charging at the charge voltage; and

in event the state-of-charge of the battery is fully charged for longer than a time threshold, halt the charging of the battery.

12. The computer-readable storage medium of claim 11, wherein the CRM instructions further comprise instructions to reduce the charge voltage by a voltage in a range of 10 mV to 50 mV each time that the cycle number exceeds the corresponding first cycle number threshold or the second cycle number threshold.

13. The computer-readable storage medium of claim 12, wherein the CRM instructions further comprise instructions to reduce the charge voltage by a first voltage based on the first cycle number threshold and reduce the charge voltage by a second voltage based on the second cycle number threshold, wherein the first voltage is different than the second voltage.

14. The computer-readable storage medium of claim 11, wherein the the CRM instructions further comprise instructions to:

in event the state-of-charge of the battery falls below a threshold state-of-charge resume the charging of the battery.