System and Method for Controlling Output of a Battery Pack

• US 20120074904A1
• Filed: 06/08/2010
• Published: 03/29/2012
• Est. Priority Date: 06/10/2009
• Status: Active Application

• Current Assignee: A123 Systems Incorporated
• Original Assignee: A123 Systems Incorporated
• Inventors: Rutkowski, Brian D., Moorhead, Brian C.
• Granted Patent: US 9,035,610 B2
• Time in Patent Office: Days
• US Class Current: 320/112
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• 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: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Systems and methods for controlling the output of a battery pack are disclosed. In one example, a battery pack contactor is opened in response to battery pack current. The system and method may reduce battery pack degradation and increase system flexibility.

Claims

1. A method for controlling output of a battery pack, comprising:

opening a contactor that electrically couples said battery pack to an electrical circuit external of said battery pack when an integrated variable or parameter related to a tracked variable of the battery pack exceeds a threshold amount, the integrated variable or parameter integrated when the tracked variable of said battery pack is greater than a threshold amount.

2. The method of claim 1, wherein the integrated variable or parameter is related to an amount of current supplied by said battery pack to a load external of said battery pack.

3. The method of claim 1, wherein the integrated variable or parameter is related to a battery cell voltage of said battery pack as influenced by a source external of said battery pack.

4. The method of claim 1, wherein the integrated variable or parameter is related to a voltage of said battery pack as influenced by a source external of said battery pack.

5. The method of claim 1, wherein the integrated variable or parameter is related to a voltage across a contactor of said battery pack influenced by a source external of the battery pack.

6. The method of claim 1, wherein the integrated variable related to a tracked variable of the battery pack increases when the tracked variable of the battery pack is greater than the threshold level plus a buffer level.

7. The method of claim 1, wherein a value of the tracked variable of the battery pack is battery current and is transmitted over a CAN link.

8. A system for controlling output of a battery pack, comprising:

a plurality of battery cells;

a current sensor in electrical communication with said plurality of battery cells;

a contactor in electrical communication with said plurality of battery cells and a load external said battery pack; and

a controller, said controller in communication with said current sensor and said contactor, said controller including instructions for opening said contactor when an integrated variable or parameter related to a tracked variable of said battery pack exceeds a threshold amount, and wherein said tracked variable is a current from said current sensor.

9. The system of claim 8, further comprising a CAN link within said battery pack, said CAN link providing current data from said current sensor to said controller.

10. The system of claim 8, further comprising a CAN link between said controller and a vehicle controller.

11. The system of claim 8, further comprising a plurality of battery modules comprised of said plurality of battery cells.

12. The system of claim 8, wherein said controller includes further instructions for integrating data from said current sensor when a current of said battery pack is greater than a threshold current.

13. The system of claim 8, wherein said controller includes further instructions for closing said contactor after executing a predetermined sequence.

14. The system of claim 8, wherein said current sensor is a shunt device, and wherein said controller is a battery pack controller.

15. A system for controlling output of a battery pack, comprising:

a plurality of battery cells;

a communication link;

a contactor;

a current sensor in electrical communication with said plurality of battery cells;

a first module including a first controller, said first controller including instructions for relaying battery pack current data in a digital format to a second module via said communication link; and

a second module including a second controller, said second controller including instructions for receiving said battery pack current data in said digital format via said communication link, said second controller including further instructions for opening said contactor when an integrated variable or parameter related to a tracked variable of said battery pack exceeds a threshold amount, and wherein said tracked variable is a current from said current sensor.

16. The system of claim 15, wherein said second module is a battery control module, and wherein said battery control module is electrically coupled to a plurality of monitor and balancing modules via said communication link, and wherein said communication link is a CAN link.

17. The system of claim 15, wherein said contactor is a normally open contactor and includes a closing coil and metallic contacts, and wherein said first module is a current sense module.

18. The system of claim 16, wherein said plurality of monitor and balance modules each include a controller and battery cell voltage monitoring circuitry.

19. The system of claim 15, wherein said plurality of battery cells are lithium-ion battery cells.

20. The system of claim 15, wherein said controller includes further instructions for closing said contactor after predetermined conditions of a sequence are met.