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

• US 8,854,012 B2
• Filed: 08/25/2011
• Issued: 10/07/2014
• Est. Priority Date: 08/25/2011
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Dai, Hongli, Mank, Richard M.
• Primary Examiner(s): Muralidar, Richard V
• Assistant Examiner(s): HENZE-GONGOLA, DAVID V
• Application Number:
  US13/217,592
• Publication Number:
  US 20130049702A1
• Time in Patent Office: 1,139 Days
• Field of Search: 320/150, 320/153, 320/130, 320/131, 320/134, 320/136
• US Class Current: 320/150
• 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 computer-implemented method for managing use of a battery corresponding to a high-voltage lithium-polymer battery in a portable electronic device, comprising:

monitoring 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;

monitoring a temperature of the battery during use of the battery with the portable electronic device;

determining an optimal charge voltage for the battery that manages swelling in the battery by;

if the temperature exceeds a temperature threshold, calculating the optimal charge voltage by incrementally reducing a first initial charge voltage based on a first cycle number threshold;

if the temperature does not exceed the temperature threshold, calculating the optimal charge voltage by incrementally reducing a second initial charge voltage based on a second cycle number threshold, wherein the second cycle number threshold is higher than the first cycle number threshold;

modifying a charging technique for the battery to charge the battery at the optimal charge voltage;

monitoring a state-of-charge of the battery during charging of the battery; and

if the battery remains in a fully charged state for longer than a time threshold,

disconnecting the battery from a charger; and

maintaining the disconnection as the battery self discharges and the state-of-charge of the battery voltage drops below the fully charged state;

when the state-of-charge of the battery falls below a threshold state-of-charge, which is less than the fully charged state, resuming charging of the battery.

2. The computer-implemented method of claim 1,

wherein the charge voltage of the battery is initially between 4.25V and 5.0V, and

wherein the charge voltage is reduced by 10 mV to 50 mV if the cycle number exceeds the first cycle number threshold while the temperature exceeds the temperature threshold or the second cycle number thresholds while the temperature does not exceed the temperature threshold.

3. A system for managing use of a battery corresponding to a high-voltage lithium-polymer battery in a portable electronic device, comprising:

a monitoring apparatus configured to;

monitor 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; and

monitor a temperature of the battery during use of the battery with the portable electronic device;

a management apparatus configured to;

determine an optimal charge voltage for the battery that manages swelling in the battery by;

if the temperature exceeds a temperature threshold, calculating the charge voltage by incrementally reducing a first initial charge voltage based on a first cycle number threshold;

if the temperature does not exceed the temperature threshold, calculating the charge voltage by incrementally reducing a second initial charge voltage based on a second cycle number threshold, wherein the second cycle number threshold is higher than the first cycle number threshold;

modify a charging technique for the battery to charge at the optimal charge voltage; and

wherein the monitoring apparatus is configured to monitor a state-of-charge of the battery during charging of the battery; and

wherein if the battery remains in a fully charged state for longer than a time threshold, the management apparatus is configured to,

disconnect the battery from a charger, and

maintain the disconnection as the battery self discharges and the state-of-charge of the battery voltage drops below the fully charged state, and

when the state-of-charge of the battery falls below a threshold state-of-charge, which is less than the fully charged state, resume charging of the battery.

4. The system of claim 3,

wherein the charge voltage of the battery is initially between 4.25V and 5.0V, and

wherein the charge voltage is reduced by 10 mV to 50 mV if the cycle number exceeds the first cycle number threshold while the temperature exceeds the temperature threshold or the second cycle number threshold while the temperature does not exceed the temperature threshold.

5. A non-transitory 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 corresponding to a high-voltage lithium-polymer battery in a portable electronic device, the method comprising:

monitoring 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;

monitoring a temperature of the battery during use of the battery with the portable electronic device;

determining an optimal charge voltage for the battery that manages swelling in the battery by;

if the temperature exceeds a temperature threshold, calculating the optimal charge voltage by incrementally reducing a first initial charge voltage based on a first cycle number threshold;

if the temperature does not exceed the temperature threshold, calculating the optimal charge voltage by incrementally reducing a second initial charge voltage based on a second cycle number threshold, wherein the second cycle number threshold is higher than the first cycle number threshold;

modifying a charging technique for the battery to charge the battery at the optimal charge voltage; and

monitoring a state-of-charge of the battery during charging of the battery; and

if the battery remains in a fully charged state for longer than a time threshold,

disconnecting the battery from a charger; and

maintaining the disconnection as the battery self discharges and the state-of-charge of the battery voltage drops below the fully charged state;

when the state-of-charge of the battery falls below a threshold state-of-charge, which is less than the fully charged state, resuming charging of the battery.

6. The non-transitory computer-readable storage medium of claim 5,

wherein the charge voltage of the battery is initially between 4.25V and 5.0V, and

wherein the charge voltage is reduced by 10 mV to 50 mV if the cycle number exceeds the first cycle number threshold while the temperature exceeds the temperature threshold or the second cycle number thresholds while the temperature does not exceed the temperature threshold.

7. A portable electronic device, comprising:

a set of components powered by a battery, wherein the battery corresponds to a high-voltage lithium-polymer battery;

a monitoring apparatus configured to;

monitor 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; and

monitor a temperature of the battery during use of the battery with the portable electronic device;

a management apparatus configured to;

determine an optimal charge voltage for the battery that manages swelling in the battery by;

if the temperature exceeds a temperature threshold, calculating the charge voltage by incrementally reducing a first initial charge voltage based on a first cycle number threshold;

if the temperature does not exceed the temperature threshold, calculating the charge voltage by incrementally reducing a second initial charge voltage based on a second cycle number threshold, wherein the second cycle number threshold is higher than the first cycle number threshold;

modify a charging technique for the battery to charge at the optimal charge voltage; and

wherein the monitoring apparatus is configured to monitor a state-of-charge of the battery during charging of the battery; and

wherein if the battery remains in a fully charged state for longer than a time threshold, the management apparatus is configured to,

disconnect the battery from a charger, and

maintain the disconnection as the battery self discharges and the state-of-charge of the battery voltage drops below the fully charged state, and

when the state-of-charge of the battery falls below a threshold state-of-charge, which is less than the fully charged state, resume charging of the battery.

8. The portable electronic device of claim 7,

wherein the charge voltage of the battery is initially between 4.25V and 5.0V, and

wherein the charge voltage is reduced by 10 mV to 50 mV if the cycle number exceeds the first cycle number threshold while the temperature exceeds the temperature threshold or the second cycle number thresholds while the temperature does not exceed the temperature threshold.