Method for determining battery capacity

• US 8,589,098 B2
• Filed: 08/20/2012
• Issued: 11/19/2013
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Ahmed, Farhad, Fu, Runbo
• Primary Examiner(s): Raymond, Edward
• Application Number:
  US13/589,524
• Publication Number:
  US 20120316816A1
• Time in Patent Office: 456 Days
• Field of Search: 702/63, 702/60, 702/64, 702182-185
• US Class Current: 702/63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An electrical device is powered by a battery. The device includes transition phase determining circuitry operatively connected to the battery to determine that the battery has entered a transition phase based on the occurrence of a change in direction of current flowing through the battery. Battery capacity determining circuitry is operatively connected to the transition phase determining circuitry and configured to determine, in response the transition phase determining circuitry determining that the battery is in the transition phase, a capacity of the battery based on a transition phase battery capacity model of capacity-vs.-voltage. The transition phase determining circuitry is further configured to determine an end of the transition phase based on the transition phase battery capacity model and a non-transition battery capacity model of capacity-vs.-voltage yielding the same capacity value for a given measured voltage of the battery.

Claims

1. A method performed by an electrical device powered by a battery, the method comprising:

monitoring voltage of the battery;

determining that the battery has entered a transition phase;

in response to determining that the battery has entered the transition phase, determining capacity of the battery based on a transition phase battery capacity model that defines the battery'"'"'s capacity as a function of the battery'"'"'s voltage;

determining that the transition phase has ended based on lapse of a predetermined time period from the start of the transition phase; and

in response to determining that the transition phase has ended, determining the capacity of the battery based on a non-transition phase battery capacity model.

2. The method of claim 1 wherein a capacity value of the transition phase model for each given voltage is calculated as a function of two capacity values yielded respectively by a non-transition charge model and a non-transition discharge model for the given voltage.

3. The method of claim 1 wherein a capacity value of the transition phase model for each given voltage is determined experimentally.

4. The method of claim 1 wherein the non-transition phase model is a charge model or a discharge model.

5. The method of claim 1 wherein the monitoring step and the determining steps are performed by a mobile communication device that is powered by the battery.

6. The method of claim 1 further comprising:

storing different transition phase models, each for a different temperature range;

measuring a current temperature of the battery; and

selecting the transition phase model, for determining the battery capacity, whose temperature range includes the current temperature of the battery;

the storing, measuring and selecting steps being performed by the electrical device that is powered by the battery.

7. A method performed by an electrical device powered by a battery, the method comprising:

monitoring voltage of the battery;

determining that the battery has entered a transition phase;

in response to determining that the battery has entered the transition phase, determining capacity of the battery based on a transition phase battery capacity model that defines the battery'"'"'s capacity as a function of the battery'"'"'s voltage;

determining that the transition phase has ended based on the battery voltage having changed by a predetermined voltage value from the battery voltage at the start of the transition phase; and

in response to determining that the transition phase has ended, determining the capacity of the battery based on a non-transition phase battery capacity model.

8. The method of claim 7 wherein a capacity value of the transition phase model for each given voltage is calculated as a function of two capacity values yielded respectively by a non-transition charge model and a non-transition discharge model for the given voltage.

9. The method of claim 7 wherein a capacity value of the transition phase model for each given voltage is determined experimentally.

10. The method of claim 7 wherein the non-transition phase model is a charge model or a discharge model.

11. The method of claim 7 wherein the monitoring step and the determining steps are performed by a mobile communication device that is powered by the battery.

12. The method of claim 7 further comprising:

storing different transition phase models, each for a different temperature range;

measuring a current temperature of the battery; and

selecting the transition phase model, for determining the battery capacity, whose temperature range includes the current temperature of the battery;

the storing, measuring and selecting steps being performed by the electrical device that is powered by the battery.

13. A method performed by an electrical device powered by a battery, the method comprising:

monitoring voltage of the battery;

determining that the battery has entered a transition phase;

in response to determining that the battery has entered the transition phase, determining capacity of the battery based on a transition phase battery capacity model that defines the battery'"'"'s capacity as a function of the battery'"'"'s voltage;

determining that the transition phase has ended based on the transition phase battery capacity model and a non-transition battery capacity model of capacity-vs.-voltage yielding the same capacity value for the monitored voltage; and

in response to determining that the transition phase has ended, determining the capacity of the battery based on the non-transition phase battery capacity model.

14. The method of claim 13 wherein a capacity value of the transition phase model for each given voltage is calculated as a function of two capacity values yielded respectively by a non-transition charge model and a non-transition discharge model for the given voltage.

15. The method of claim 13 wherein a capacity value of the transition phase model for each given voltage is determined experimentally.

16. The method of claim 13 wherein the non-transition phase model is a charge model or a discharge model.

17. The method of claim 13 wherein the monitoring step and the determining steps are performed by a mobile communication device that is powered by the battery.

18. The method of claim 13 further comprising:

storing different transition phase models, each for a different temperature range;

measuring a current temperature of the battery; and

selecting the transition phase model, for determining the battery capacity, whose temperature range includes the current temperature of the battery;

the storing, measuring and selecting steps being performed by the electrical device that is powered by the battery.