Protection of a thin-layer battery by periodically operating battery at maximum discharge current

• US 8,810,204 B2
• Filed: 09/01/2011
• Issued: 08/19/2014
• Est. Priority Date: 09/07/2010
• Status: Expired due to Fees

• Current Assignee: Stmicroelectronics Tours SAS (STMicroelectronics NV)
• Original Assignee: Stmicroelectronics Tours SAS (STMicroelectronics NV)
• Inventors: Cantin, Frdric
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US13/223,920
• Publication Number:
  US 20120019211A1
• Time in Patent Office: 1,083 Days
• Field of Search: 320/107, 320/114, 320/115, 320/127, 320/131, 320/132, 320/135, 320/136
• US Class Current: 320/135
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A method for protecting a thin-layer battery connected to an intermittent load including the steps of periodically operating the battery at its maximum discharge current, and disconnecting the battery as soon as the voltage across it reaches a threshold value greater than its critical voltage for the maximum discharge current.

Claims

1. A method for protecting a thin-layer battery connected to an intermittent load comprising the steps of:

periodically operating the battery at its maximum discharge current, and

disconnecting the battery as soon as the voltage across it reaches a threshold value greater than its critical voltage for said maximum discharge current.

2. The method of claim 1, wherein the periodic operation has a duty cycle smaller than 0.1%.

3. The method of claim 1, wherein the duration of each phase of the periodic operation is shorter than 10 ms.

4. The method of claim 1, wherein the period of the periodic operation is shorter than 10 minutes.

5. A device for protecting a thin-layer battery connected to an intermittent load comprising:

a switchable load capable of periodically operating the battery at its maximum discharge current, and

a voltage comparator capable of comparing the voltage across the battery with a threshold value greater than the critical voltage of the battery for said maximum discharge current.

6. The device of claim 5, wherein the switchable load is controlled by first switching means having a duty cycle smaller than 0.1%.

7. The device of claim 6, wherein the first switching means are capable of forming a signal formed of square pulses having a width smaller than 10 ms.

8. The device of claim 6, wherein the first switching means are capable of forming a signal having a period shorter than 10 minutes.

9. The device of claim 5, comprising a buffer capacitor in parallel on the intermittent load.

10. The device of claim 9, comprising second switching means arranged between the assembly comprised of the battery and of the switchable load and the assembly comprised of the buffer capacitor and of the intermittent load.

11. The device of claim 5, wherein the switchable load is a current source.

12. A method for operating a battery connected to an intermittent load, comprising:

supplying current to the intermittent load during a normal operating mode;

supplying a maximum discharge current from the battery to a switchable load periodically during a forced operating mode; and

disconnecting the battery from the intermittent load when a voltage of the battery drops to a threshold value greater than a critical battery voltage at the maximum discharge current.

13. A method for operating a battery as defined in claim 12, wherein supplying current to the intermittent load comprises supplying current to the intermittent load from the battery and from a buffer capacitor when the forced operating mode is inactive.

14. A method for operating a battery as defined in claim 13, wherein supplying current to the intermittent load comprises supplying current to the intermittent load from the buffer capacitor when the forced operating mode is active.

15. A method for operating a battery as defined in claim 12, wherein the normal operating mode and the forced operating mode overlap in time.

16. A method for operating a battery as defined in claim 12, wherein a duty cycle of the forced operating mode is less than 0.1%.

17. A method for operating a battery as defined in claim 12, wherein a duration of the forced operating mode is less than 10 milliseconds.

18. A method for operating a battery as defined in claim 12, wherein a period of the forced operating mode is less than 10 minutes.

19. A method for operating a battery as defined in claim 12, adapted for operation of a thin-layer battery.

20. A method for operating a battery as defined in claim 12, adapted for operation of a lithium ion battery.

21. A device for protecting a battery connected to an intermittent load, comprising:

a switchable load configured to periodically operate the battery at a maximum discharge current in a forced operating mode;

a comparator configured to compare a voltage of the battery with a threshold value greater than a critical battery voltage at the maximum discharge current; and

a first switch configured to disconnect the battery from the intermittent load when the comparator detects that the battery voltage has crossed the threshold value.

22. A device for protecting a battery as defined in claim 21, further comprising a buffer capacitor coupled in parallel with the intermittent load.

23. A device for protecting a battery as defined in claim 22, further comprising a second switch in series with the switchable load and a third switch coupled between the switchable load and the intermittent load.

24. A device for protecting a battery as defined in claim 21, wherein the switchable load comprises a current source.

25. A device for protecting a battery as defined in claim 21, wherein a duty cycle of the forced operating mode is less than 0.1%.

26. A device for protecting a battery as defined in claim 21, wherein a duration of the forced operating mode is less than 10 milliseconds.

27. A device for protecting a battery as defined in claim 21, wherein a period of the forced operating mode is less than 10 minutes.

28. A device for protecting a battery as defined in claim 21, configured to protect a thin-layer battery.

29. A device for protecting a battery as defined in claim 21, configured to protect a lithium ion battery.

30. A device for protecting a battery as defined in claim 23, wherein the second switch is closed and the third switch is open when the switchable load periodically operates the battery at the maximum discharge current.