IP Library Granted Patent US 8,415,926
Granted Patent B2
US 8,415,926 · App. 12/581,721 · Granted Apr 9, 2013

In-situ battery health detector and end-of-life indicator

Inventors: Ramesh C. Bhardwaj (Fremont, CA); Taisup Hwang (Santa Clara, CA); Richard M. Mank (Sunnyvale, CA)
Assignee: Apple Inc.
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Quick Facts
Patent No.
US 8,415,926
App. No.
12/581,721
Granted
Apr 9, 2013
Kind
B2
Abstract

Some embodiments provide a system that monitors a battery in a portable electronic device. During operation, the system applies a pulse load to the battery and determines an impedance of the battery by measuring a voltage of the battery during the pulse load. Next, the system assesses a health of the battery based on the impedance. Finally, the system uses the assessed health to manage use of the battery in the portable electronic device.

Claims (18)

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

applying a pulse load to the battery;

determining an impedance of the battery by measuring a voltage of the battery during the pulse load;

assessing a health of the battery based on the impedance by analyzing a linearity of the impedance of the battery for at least two separate charge-discharge cycles performed on the battery; and

using the assessed health to manage use of the battery in the portable electronic device.

2. The computer-implemented method of claim 1 , wherein determining the impedance of the battery involves:

measuring the voltage of the battery in a fully charged state;

calculating a drop in the voltage after the pulse load is applied; and

dividing the drop in the voltage by a current of the pulse load.

3. The computer-implemented method of claim 1 , wherein a lack of linearity corresponds to degradation in the battery.

4. The computer-implemented method of claim 1 , wherein using the assessed health to manage use of the battery in the portable electronic device involves at least one of:

adjusting a charge voltage for the battery;

notifying a user of the portable electronic device of an end-of-life for the battery; and

isolating a cell in the battery.

5. The computer-implemented method of claim 4 , wherein adjusting the charge voltage for the battery involves:

decreasing the charge voltage to extend a cycle life of the battery and to control cell swelling within the battery.

6. The computer-implemented method of claim 4 , wherein adjusting the charge voltage for the battery involves:

stopping charging of the battery at the end-of-life for the battery.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 23, 2010
From: BHARDWAJ, RAMESH C.; HWANG, TAISUP; MANK, RICHARD M.
To: APPLE INC.
Reel/Frame 023978/0722 →
Continuity (1)
Related Publication 20110089907A1 · Apr 21, 2011