EXTENDING BATTERY LIFE FOR A RECHARGEABLE BATTERY

• US 20140217984A1
• Filed: 09/08/2011
• Published: 08/07/2014
• Est. Priority Date: 09/08/2011
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Banerjee, Neel, Clarkson, Anton Nicholas, Mabeck, Jeffrey Todd
• Granted Patent: US 9,425,630 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• 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: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Technology is described for extending battery life for a rechargeable battery. The method can include estimating a desired energy storage for the rechargeable battery in an electronic device during an operating time period. Expected active periods for the rechargeable battery can be determined. A defined charge voltage can be computed based on the desired energy storage and expected active periods of the rechargeable battery in the electronic device. In addition, the rechargeable battery can be charged to the defined charge voltage.

Claims

1. A method for extending battery life for a rechargeable battery, comprising:

estimating a desired energy storage for the rechargeable battery in an electronic device during an operating time period;

determining expected active periods for the rechargeable battery during the operating time period;

computing a defined charge voltage based on the desired energy storage and expected active periods of the rechargeable battery in the electronic device; and

charging the rechargeable battery to the defined charge voltage.

2. The method as in claim 1, further comprising computing an estimated temperature exposure over the operating time period of the rechargeable battery to use in calculating the defined charge voltage for the rechargeable battery.

3. The method as in claim 2, further comprising applying a correction factor for the actual battery cell temperature when computing the defined charge voltage.

4. The method as in claim 1, further comprising using a history of the rechargeable battery to compute the defined charge voltage.

5. The method as in claim 1, further comprising taking into account the historical self-discharge of the rechargeable battery to determine the defined charge voltage.

6. The method as in claim 1, further comprising a power profile for the electronic device to determine the defined charge voltage.

7. The method as in claim 1, further comprising defining the dormant time for the rechargeable battery to determine the defined charge voltage.

8. The method as in claim 1, further comprising using a database to store historical battery attributes used for finding the defined charge voltage.

9. The method as in claim 8, further comprising using the database to store the last capacity of the rechargeable battery.

10. The method as in claim 8, further comprising using the database to record an average rechargeable battery temperature during use of the rechargeable battery in order to update temperature and capacity loss models.

11. The method as in claim 1, further comprising tuning the target end-of-discharge voltage to increase battery lifetime.

12. A method for extending battery life of a rechargeable battery, comprising:

obtaining a discharge curve for the rechargeable battery;

obtaining a maximum allowed charge voltage for the rechargeable batten and a minimum end-of-discharge voltage using the discharge curve;

reducing a charge voltage iteratively to find a minimum charge voltage based on energy capacity for a projected use of the rechargeable battery in an electronic device;

increasing the end-of-discharge voltage iteratively while keeping the charge voltage at a maximum allowed charge voltage to find a maximum end-of-discharge voltage for the energy capacity for the projected use; and

setting the charge voltage and target end-of-discharge voltage by increasing the charge voltage from the minimum charge voltage or decreasing the end-of-discharge voltage from the maximum end-of-discharge voltage until the energy capacity for the projected use is reached for the rechargeable battery.

13. The method as in claim 12, further comprising defining the charge voltage based on a history of the rechargeable battery.

14. The method as in claim 12, further comprising defining the charge voltage based on computing a temperature exposure of the rechargeable battery during an operating time period.

15. The method as in claim 12, further comprising defining the charge voltage based on determining the expected active and dormant periods for the rechargeable battery.

16. The method as in claim 12, further comprising defining the charge voltage based on an estimated future average air temperature over the operating time period.

17. The method as in claim 12, further comprising applying a correction factor for the actual battery cell temperature.

18. The method as in claim 12, further comprising taking into account a historical self discharge of the rechargeable battery, a power profile for the electronic device, a last capacity of the rechargeable battery, or an average rechargeable battery temperature expected during use of the rechargeable battery.

19. A system for extending battery life for a rechargeable battery, comprising:

a database to store historical battery attribute data;

a capacity loss module to determine capacity loss of the rechargeable battery over time;

a total active time module to record active use time for the rechargeable battery; and

a charging computation module to compute a charging voltage based on the historical battery attribute data, the capacity loss and the active use time; and

a charging module to re-charge the rechargeable battery at the computed charging voltage.

20. The system as in claim 19, further comprising electronic device sensors to record battery energy used, battery temperature, and battery sleep time for recording in the database.