Method for determining battery capacity

• US 7,676,335 B2
• Filed: 11/27/2007
• Issued: 03/09/2010
• 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:
  US11/945,765
• Publication Number:
  US 20080086277A1
• Time in Patent Office: 833 Days
• Field of Search: 702/63, 702/64, 702/66, 702/69, 702182-185, 702/188
• 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

A method includes monitoring the voltage of a power source connector for charging a battery. A determination is made that the battery has entered a transition phase based on sensing an abrupt change in the voltage. In response to determining that the battery is in the transition phase, a capacity of the battery is determined based on a transition phase battery capacity model that defines the battery'"'"'s capacity as a function of the battery'"'"'s voltage.

Claims

1. A method comprising:

monitoring the voltage of a power source connector for charging a battery;

determining that the battery has entered a transition phase based on sensing an abrupt change in the voltage; and

in response to determining that the battery is in the transition phase, determining a 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;

the transition phase occurring upon connection of the battery to a power source or disconnection of the battery from a power source, in which the battery'"'"'s capacity as a function of voltage differs from both a charge curve and a discharge curve of the battery.

2. The method of claim 1 wherein the determination step includes determining that the battery has entered a transition phase from discharging to charging based on sensing an abrupt increase in the connector voltage.

3. The method of claim 1 wherein the determination step includes determining that the battery has entered a transition phase from charging to discharging based on sensing an abrupt decrease in the connector voltage.

4. The method of claim 1 wherein the abrupt change is from 0V to a predetermined voltage value or from a predetermined voltage value to 0V.

5. The method of claim 1 further comprising:

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

6. The method of claim 1 further comprising:

determining that the transition phase has ended based on the battery'"'"'s voltage having changed by a predetermined voltage value from the battery'"'"'s voltage at the start of the transition phase.

7. The method of claim 1 further comprising:

determining the transition phase battery capacity model from both a non-transition battery capacity charge model and a non-transition battery capacity discharge model, all three models defining the battery'"'"'s capacity as a function of the battery'"'"'s voltage.

8. A handheld device configured to perform the method of claim 1.

9. A method comprising:

determining that a battery has entered a transition phase initiated by a change in direction of current through the battery;

in response to determining that the battery is in the transition phase, determining a 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; and

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

the transition phase occurring upon connection of the battery to a power source or disconnection of the battery from a power source, in which the battery'"'"'s capacity as a function of voltage differs from both a charge curve and a discharge curve of the battery.

10. The method of claim 9 further comprising:

in response to determining the end of the transition phase, ceasing to base the capacity determination on the transition phase battery capacity model.

11. The method of claim 9 further comprising:

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

12. A handheld device configured to perform the method of claim 9.

13. A method comprising:

determining that a battery has entered a transition phase initiated by a change in direction of current through the battery;

in response to determining that the battery is in the transition phase, determining a 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; and

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;

the transition phase occurring upon connection of the battery to a power source or disconnection of the battery from a power source, in which the battery'"'"'s capacity as a function of voltage differs from both a charge curve and a discharge curve of the battery.

14. The method of claim 13 further comprising:

in response to determining the end of the transition phase, ceasing to base the capacity determination on the transition phase battery capacity model.

15. The method of claim 13 further comprising:

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

16. A handheld device configured to perform the method of claim 13.

17. A method comprising:

determining a transition phase battery capacity model as a function of both a non-transition battery capacity charge model and a non-transition battery capacity discharge model, all three models defining a battery'"'"'s capacity as a function of its voltage;

the transition phase occurring upon connection of the battery to a power source or disconnection of the battery from a power source, in which the battery'"'"'s capacity as a function of voltage differs from both a charge curve and a discharge curve of the battery.

18. The method of claim 17 wherein the capacity value of the transition phase model for each given voltage is a function of the two capacity values yielded by the two non-transition models for the given voltage.

19. The method of claim 17 further comprising:

using the transition phase model to determine capacity of a battery.

20. A method comprising:

determining if a battery is in a charging state, a discharging state, or a transition phase, the transition phase occurring upon connection of the battery to a power source or disconnection of the battery from a power source, in which the battery'"'"'s capacity as a function of voltage differs from both a charge curve and a discharge curve of the battery;

if the battery is in the charging state, then determining the battery'"'"'s capacity through the battery'"'"'s charge capacity model as a function of voltage;

if the battery is in the discharging state, then determining the battery'"'"'s capacity through the battery'"'"'s discharge capacity model as a function of voltage;

if the battery is in the transition phase, then determining the battery'"'"'s capacity through a transition capacity model as a function of voltage.

21. The method of claim 20 further comprising:

determining that the battery has entered the transition phase based on sensing an abrupt change in the battery'"'"'s voltage.

22. The method of claim 20 further comprising:

determining that the battery has entered the transition phase based on sensing a change in direction of current through the battery.

23. The method of claim 20 wherein a capacity value of the transition phase model for each given voltage is a function of the two capacity values yielded by the charge model and discharge model for the given voltage.