SYSTEM AND METHOD OF BATTERY CAPACITY ESTIMATION

• US 20110238344A1
• Filed: 06/10/2011
• Published: 09/29/2011
• Est. Priority Date: 09/24/2002
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Nie, Junhong, Pomeroy, Stephen L., Bouianovskaia, Reguina, Shah, Samir R., Bugnariu, Calin N., Islam, M. Khaledul, Jin, Xin
• Granted Patent: US 8,655,613 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

A method includes measuring an operating parameter of a battery of a mobile device. The measured operating parameter is translated into an equivalent series resistance (ESR) value. The ESR value is adjusted by a correction factor to generate a corrected ESR value. The capacity of the battery is determined based on the corrected ESR value. The correction factor is automatically calibrated based on the measured operating parameter.

Claims

1. A method comprising:

measuring an operating parameter of a battery of a mobile device;

translating the measured operating parameter into an equivalent series resistance (ESR) value;

adjusting the ESR value by a correction factor to generate a corrected ESR value;

determining the capacity of the battery based on the corrected ESR value; and

automatically calibrating the correction factor based on the measured operating parameter.

2. The method of claim 1 further comprising:

using the measured operating parameter to estimate an actual ESR value;

the correction factor being automatically calibrated using the estimated ESR value.

3. The method of claim 1 wherein the operating parameter is a temperature of the battery.

4. The method of claim 1 further comprising measuring a loaded voltage of the battery, and the determining step includes:

determining an unloaded battery voltage based on the corrected ESR value and the measured loaded battery voltage; and

determining the capacity of the battery based on the unloaded battery voltage.

5. The method of claim 1 wherein the measuring, translating, adjusting, determining and automatically calibrating steps are performed by the mobile device.

6. The method of claim 1 wherein the mobile device is a mobile communication device.

7. A method comprising:

measuring an operating parameter of a battery of a mobile device;

accessing a profile table, that relates battery profile values to corresponding operating parameter values, to translate the measured operating parameter into an equivalent series resistance (ESR) value; and

determining the capacity of the battery based on the ESR value.

8. The method of claim 7 further comprising, after the determining step:

automatically calibrating the correction factor based on the measured operating parameter.

9. The method of claim 7, wherein the operating parameter is a temperature of the battery.

10. The method of claim 7 further comprising measuring a loaded voltage of the battery, and the determining step includes:

determining an unloaded battery voltage based on the corrected ESR value and the measured loaded battery voltage; and

determining the capacity of the battery based on the unloaded battery voltage.

11. The method of claim 7 wherein the measuring, accessing and determining steps are performed by the mobile device.

12. The method of claim 7 further comprising:

displaying a message, on the mobile device, advising a user to warm the mobile device to increase the battery capacity.

13. The method of claim 7 further comprising:

displaying a message, on the mobile device, advising a user to move to another location to increase battery capacity.

14. The method of claim 7 wherein the mobile device is a mobile communication device.

15. The method of claim 14 further comprising:

measuring, by the mobile device, during a call conducted by the mobile device, a first voltage of the battery and a first current drawn from the battery and a temperature of the battery; and

measuring, by the mobile device, after the call has ended but before the temperature noticeably changes, both a second voltage of the battery and a second current drawn from the battery; and

calculating the ESR as a function of a difference between the first and second voltages and a difference between first and second currents.

16. The method of claim 15 further comprising:

adding, to the profile table, an entry relating the calculated ESR to the measured temperature.

17. The method of claim 15 wherein the measuring of the first current includes:

measuring transmit power of the mobile device; and

translating the measured transmit power into said first current, using a table that relates transmit power to battery current.

18. A mobile device comprising:

a memory device;

a battery;

a profile table stored in the memory device that relates battery profile values to corresponding operating parameter values;

a sensor circuit configured to measure an operating condition of the battery; and

a battery capacity estimation program configured to access the profile table to translate the measured operating parameter into an equivalent series resistance (ESR) value, and to determine the capacity of the battery based on the ESR value.