BATTERY CHARGING TOP-OFF

• US 20130193912A1
• Filed: 01/27/2012
• Published: 08/01/2013
• Est. Priority Date: 01/27/2012
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Bornhoft, Reid K.
• Granted Patent: US 9,362,774 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/00718 in response to charge current gradient

Abstract

This disclosure describes techniques for a method of charging a battery. In an example, the method includes determining a capacity of the battery, and determining a state of charge of the battery. The method also includes charging the battery with a charging current, wherein the charging current is based on the capacity of the battery and the state of charge of the battery, and wherein charging the battery comprises reducing the charging current in response to the state of charge of the battery changing with respect to the capacity of the battery.

Claims

1. A method of charging a battery, the method comprising:

determining a capacity of the battery;

determining a state of charge of the battery; and

charging the battery with a charging current, wherein the charging current is based on the capacity of the battery and the state of charge of the battery, and wherein charging the battery comprises reducing the charging current in response to the state of charge of the battery changing with respect to the capacity of the battery.

2. The method of claim 1, further comprising determining a voltage limit for the battery, and wherein charging the battery comprises maintaining a voltage of the battery below the voltage limit.

3. The method of claim 1, wherein determining the capacity of the battery comprises determining a maximum number of storable amp-hours of the battery.

4. The method of claim 3, wherein determining the state of charge of the battery comprises determining a difference between a current number of stored amp-hours of the battery and the maximum number of storable amp-hours of the battery.

5. The method of claim 4, further comprising measuring the current number of stored amp-hours using a coulomb counter.

6. The method of claim 3, wherein the maximum number of storable amp-hours of the battery is an estimated value, and further comprising decreasing the estimated value after fully charging the battery based on a number of amp-hours needed to fully charge the battery.

7. The method of claim 1, wherein reducing the charging current is performed during a top-off session that comprises charging of a final twenty percent of the capacity of the battery.

8. The method of claim 1, wherein charging the battery comprises a transcutaneous inductive transfer of charge to the battery.

9. The method of claim 1, wherein the battery resides within an implantable medical device, wherein charging the battery comprises charging the battery with a medical device charger.

10. The method of claim 1, further comprising stopping charging the battery upon reducing the charging current to a minimum charging current cut off.

11. An implantable medical device (IMD) comprising:

a battery configured to power the IMD;

a memory storing instructions;

one or more processors configured to execute the instructions, wherein upon execution of the instructions, the one or more processors cause;

determining a capacity of the battery;

determining a state of charge of the battery; and

charging the battery with a charging current, wherein the charging current is based on the capacity of the battery and the state of charge of the battery, and wherein charging the battery comprises reducing the charging current in response to the state of charge of the battery changing with respect to the capacity of the battery.

12. The IMD of claim 11, wherein upon execution of the instructions, the one or more processors further cause:

determining a voltage limit for the battery, and wherein charging the battery comprises maintaining a voltage of the battery below the voltage limit.

13. The IMD of claim 11, wherein determining the capacity of the battery comprises determining a maximum number of storable amp-hours of the battery.

14. The IMD of claim 13, wherein determining the state of charge of the battery comprises determining a difference between a current number of stored amp-hours of the battery and the maximum number of storable amp-hours of the battery.

15. The IMD of claim 14, further comprising a coulomb counter configured to measure the current number of stored amp-hours.

16. The IMD of claim 13, wherein the maximum number of storable amp-hours of the battery is an estimated value, and wherein upon execution of the instructions, the one or more processors further cause:

decreasing the estimated value after fully charging the battery based on a number of amp-hours needed to fully charge the battery.

17. The IMD of claim 11, wherein reducing the charging current is performed during a top-off session that comprises charging of a final twenty percent of the capacity of the battery.

18. The IMD of claim 11, further comprising a charging module configured to inductively transfer charge to the battery transcutaneously

19. The IMD of claim 11, wherein upon execution of the instructions, the one or more processors further cause:

stopping charging the battery upon reducing the charging current to a minimum charging current cut off.

20. An apparatus for charging a battery, the apparatus comprising:

means for determining a capacity of the battery;

means for determining a state of charge of the battery; and

means for charging the battery with a charging current, wherein the charging current is based on the capacity of the battery and the state of charge of the battery, and wherein charging the battery comprises reducing the charging current in response to the state of charge of the battery changing with respect to the capacity of the battery.

21. The apparatus of claim 20, further comprising means for determining a voltage limit for the battery, and wherein charging the battery comprises maintaining a voltage of the battery below the voltage limit.

22. The apparatus of claim 20, wherein determining the capacity of the battery comprises determining a maximum number of storable amp-hours of the battery.

23. The apparatus of claim 22, wherein determining the state of charge of the battery comprises determining a difference between a current number of stored amp-hours of the battery and the maximum number of storable amp-hours of the battery.

24. The apparatus of claim 22, wherein the maximum number of storable amp-hours of the battery is an estimated value, and further comprising means for decreasing the estimated value after fully charging the battery based on a number of amp-hours needed to fully charge the battery.

25. The apparatus of claim 20, wherein reducing the charging current is performed during a top-off session that comprises charging of a final twenty percent of the capacity of the battery.

26. The apparatus of claim 20, further comprising means for inductively transferring charge to the battery transcutaneously.

27. The apparatus of claim 20, further comprising means for stopping charging the battery upon reducing the charging current to a minimum charging current cut off.