Battery pack with locally controlled disconnect safeguards

Patent metadata

Field	Value
Publication number	US-9601940-B2
Application number	US-201414452311-A
Country	US
Kind code	B2
Filing date	Aug 5, 2014
Priority date	Aug 6, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

Embodiments of the present invention are directed to an improved battery packaging design. The battery pack design may include a battery cell, a plurality of transistors, and a controller. The transistors may be coupled to the terminals of the battery cell in an H-bridge configuration. The controller may control the transistors to bypass the battery cell based on the current flowing between the output terminals of the battery pack. In such a manner, the controller may prevent damage to the battery cell and improve the overall safety of the battery pack in hazardous conditions.

First claim

We claim:

1. A battery pack comprising:
a first battery cell stage comprising:
a first pair of output terminals;
a first battery cell;
a first set of switches comprising two pairs of switches coupling the first battery cell to the first pair of output terminals in an H-bridge configuration; and
a first local controller programmed to control the first set of switches to selectively connect and disconnect the first battery cell to the first pair of output terminals, wherein the first battery cell, the first set of switches, and the first local controller are provided in a common package; and

a second battery cell stage comprising:
a second pair of output terminals, wherein a first output terminal of the second pair of output terminals is electrically coupled to a first output terminal of the first pair of output terminals;
a second battery cell;
a second set of switches comprising two pairs of switches coupling the second battery cell the second pair of output terminals in an H-bridge configuration; and
a second local controller programmed to control the second set of switches to selectively connect and disconnect the second battery cell to the second pair of output terminals.

2. The battery pack of claim 1 , wherein the package is a water-tight enclosure.

3. The battery pack of claim 1 , wherein the first local controller is programmed to cause the switches to disconnect the first battery cell from the output terminals upon detection of an operating fault at the first battery cell.

4. The battery pack of claim 3 , wherein the fault is an excess amount of current flow through the output terminals.

5. The battery pack of claim 3 , wherein the fault is an excess amount of heat detected in the package.

6. The battery pack of claim 3 , wherein the fault is a depleted level of charge of the first battery cell.

7. The battery pack of claim 3 , wherein the fault is an absence of communication signals received by the controller from outside the package.

8. The battery pack of claim 1 , wherein:
a first pair of switches of the two pairs of switches of the first set of switches are depletion mode transistors that conduct current in an off state and do not conduct current in an on state; and
a second pair of switches of the two pairs of switches of the first set of switches are enhancement mode transistors that conduct current in an on state and do not conduct current in an off state.

9. The battery pack of claim 1 , wherein:
during an active state, either the first pair of switches of the two pairs of switches of the first set of switches conduct current and a second pair of switches of the two pairs of switches of the first set of switches do not conduct current or the first pair of switches do not conduct current and the second pair of switches conduct current;
during a bypass state, only one switch in each of the pairs of switches of the first set of switches conducts current; and
during a fault state, at least three of the switches in the pairs of switches of the first set of switches do not conduct current.

10. The battery pack of claim 9 , wherein the two pairs of switches of the first set of switches comprise transistors are metal-oxide-semiconductor-field-effect transistors (MOSFETs).

11. The battery pack of claim 9 , further comprising a diode coupled between two terminals of each transistor.

12. The battery pack of claim 1 , wherein the first local controller is programmed to transmit commands signals outside the package.

13. The battery pack of claim 1 , further comprising a sensor to measure the amount of current flowing between the output terminals.

14. The battery pack of claim 1 , wherein the first output terminal of the second pair of output terminals is electrically coupled to a first terminal of a first switch of the second set of switches, and wherein a second terminal of the first switch of the second set of switches is electrically coupled to the first output terminal of the first pair of output terminals.

15. A system comprising:
a plurality of battery packs coupled to each other, the plurality of battery packs comprising:
a first battery pack, comprising:
a first battery cell;
a first pair of output terminals;
a first set of switches comprising two pairs of switches coupling the first battery cell to the first pair of output terminals in an H-bridge configuration; and
a first local controller to control the first set of switches to selectively connect and disconnect the first battery cell to the first pair of output terminals; and

a second battery pack, comprising:
a second batter cell;
a second pair of output terminals, wherein a first output terminal of the second pair of output terminals is electrically coupled to a first output terminal of the first pair of output terminals;
a second set of switches comprising two pairs of switches coupling the second battery cell to the second pair of output terminals in an H-bridge configuration; and
a second local controller to control the second set of switches to selectively connect and disconnect the second battery cell to the second pair of output terminals; and

a communication system coupled to the first local controller and the second local controller to allow communication between the battery packs,
wherein at least the first battery cell, the first set of switches, and the first local controller are provided in a common package.

16. The system of claim 15 , wherein the package is a water-tight enclosure.

17. The system of claim 15 , wherein the first local controller causes the first set of switches to disconnect the first battery cell from the first pair of output terminals upon detection of an operating fault.

18. The system of claim 17 , wherein the fault is an excess amount of current flow through the output terminals.

19. The system of claim 17 , wherein the fault is an excess amount of heat detected in the package.

20. The system of claim 17 , wherein the fault is a depleted level of charge of the battery cell.

21. The system of claim 17 , wherein the fault is an absence of communication signals received by the controller from outside the package.

22. The system of claim 15 , wherein:
a first pair of switches of the two pairs of switches of the first set of switches are depletion mode transistors that conduct current in an off state and do not conduct current in an on state; and
a second pair of switches of the two pairs of switches are enhancement mode transistors that conduct current in an on state and do not conduct current in an off state.

23. The system of claim 22 , wherein the transistors are metal-oxide-semiconductor-field-effect transistors (MOSFETs).

24. The system of claim 22 , further comprising a diode coupled between two terminals of each transistor.

25. The system of claim 15 , wherein the local controller transmits command signals outside the battery pack via the communication system.

26. The system of claim 15 , wherein the communication system is bidirectional.

27. The system of claim 15 , wherein the communication system is bidirectional.

28. The system of claim 15 , further comprising a sensor to measure an amount of current flowing between the output terminals.

29. The system of claim 15 , wherein the local controller receives and transmits command signals to neighboring battery packs.

Assignees

• Analog Devices Inc

Inventors

• Camp James C
• Macleod Thomas M

Classifications

• H02J7/585

  Sequential battery discharge in systems with a plurality of batteries · CPC title

• H02J7/63

  against overdischarge · CPC title

• H02J7/977

  of the battery · CPC title

• H02J7/855

  with circuits adapted for supplying loads from the battery · CPC title

• H02J7/94

  in response to battery current · CPC title