Short Detection in Battery Cells

• US 20130018606A1
• Filed: 07/14/2011
• Published: 01/17/2013
• Est. Priority Date: 07/14/2011
• Status: Active Grant

• Current Assignee: Southwest Electronic Energy Corporation (Ultralife Corporation)
• Original Assignee: Southwest Electronic Energy Corporation (Ultralife Corporation)
• Inventors: White, David A., Benckenstein, Claude L. Jr.
• Granted Patent: US 9,097,774 B2
• Time in Patent Office: Days
• US Class Current: 702/58
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• 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: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries

Abstract

Internal shorts and other failures in lithium-ion battery cells may be detected during balancing of the battery cells. A counter may be used to detect when a battery cell is behaving differently than other battery cells by balancing more or less frequently. The counter may increment each time a battery cell is balanced to the other battery cells. A misbehaving battery cell may be flagged, when the counter exceeds a threshold value, for safety checks before an overheating event occurs. This misbehaving battery cell may be faulty due to an internal short. If the faulty battery cell is not corrected by replacement with a different battery cell or corrected by a user resetting the counter, the misbehaving battery cell may be disconnected to prevent the overheating event.

Claims

1. A method comprising:

monitoring a plurality of battery cells;

counting a number of times at least one battery cell of the plurality of battery cells is out of balance with other battery cells of the plurality of battery cells; and

marking the at least one battery cell as faulty based, in part, on the counted number of times.

2. The method of claim 1, in which the at least one battery cell is marked faulty when the number of times exceeds a threshold value based, in part, on a number of times the at least one battery cell is out of balance with other battery cells.

3. The method of claim 1, further comprising:

storing a time associated with the count when at least one battery cell is out of balance with other battery cells, the time indicating when the at least one battery cell is out of balance with other battery cells; and

storing a quantity associated with the count when the at least one battery cell is out of balance with the other battery cells, the quantity indicating a charge difference between the at least one battery cell and the other battery cells,

in which marking the at least one battery cell as faulty is also based, in part, on the time and quantity of each counted time the at least one battery cell is out of balance with other battery cells.

4. The method of claim 3, in which marking the at least one battery cell as faulty comprises comparing the counted number of times, quantity information, and time information with at least one known historical profile of a faulty battery cell.

5. The method of claim 1, in which the step of monitoring the plurality of battery cells comprises monitoring battery cells in a plurality of battery pack system modules, and the method further comprises replacing at least one battery pack system module of the plurality of battery pack system modules containing the at least one battery cell marked as faulty.

6. The method of claim 1, in which the step of marking comprises determining the at least one battery cell has an internal short.

7. The method of claim 1, further comprising:

transmitting a message to a user that the at least one battery cell is faulty; and

disconnecting the at least one battery cell marked as faulty.

8. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code to monitor a plurality of battery cells;

code to count a number of times at least one battery cell of the plurality of battery cells is out of balance with other battery cells of the plurality of battery cells; and

code to mark the at least one battery cell as faulty based, in part, on the counted number of times.

9. The computer program product of claim 8, in which the code to mark comprises code to mark the at least one battery cell faulty when the number of times exceeds a threshold value based, in part, on a number of times the at least one battery cell is balanced to other battery cells of the plurality of battery cells.

10. The computer program product of claim 8, in which the medium further comprises:

code to store a time associated with the count when at least one battery cell is out of balance with other battery cells, the time indicating when the at least one battery cell is out of balance with other battery cells; and

code to store a quantity associated with the count when the at least one battery cell is out of balance with the other battery cells, the quantity indicating a charge difference between the at least one battery cell and the other battery cells,

in which marking the at least one battery cell as faulty is also based, in part, on the time and quantity of each counted time the at least one battery cell is out of balance with other battery cells.

11. The computer program product of claim 10, in which the medium further comprises code to compare the counted number of times, quantity information, and time information with at least one known historical profile of a faulty battery cell.

12. The computer program product of claim 8, in which the code to mark comprises code to determine the at least one battery cell has an internal short.

13. The computer program product of claim 8, in which the medium further comprises:

code to disconnect the at least one battery cells marked as faulty; and

code to transmit a message to a user that the at least one battery cell is faulty.

14. An apparatus, comprising:

a plurality of battery cells; and

a microprocessor coupled to the plurality of battery cells, in which the microprocessor is configured;

to monitor the plurality of battery cells;

to count a number of times at least one battery cell of the plurality of battery cells is out of balance with other battery cells of the plurality of battery cells; and

to mark the at least one battery cell as faulty based, in part, on the counted number of times.

15. The apparatus of claim 14, in which the microprocessor is configured to mark the at least one battery cell faulty when the number of times exceeds a threshold value based, in part, on a number of times the at least one battery cell is balanced to other battery cells of the plurality of battery cells.

16. The apparatus of claim 14, in which the microprocessor is further configured:

to store a time associated with the count when at least one battery cell is out of balance with other battery cells, the time indicating when the at least one battery cell is out of balance with other battery cells; and

to store a quantity associated with the count when the at least one battery cell is out of balance with the other battery cells, the quantity indicating a charge difference between the at least one battery cell and the other battery cells,

in which marking the at least one battery cell as faulty is also based, in part, on the time and quantity of each counted time the at least one battery cell is out of balance with other battery cells.

17. The apparatus of claim 16, in which marking the at least one battery cell as faulty comprises comparing the counted number of times, quantity information, and time information with at least one known historical profile of a faulty battery cell.

18. The apparatus of claim 14, in which the microprocessor is further configured to transmit a message to a user that the at least one battery cell is faulty.

19. The apparatus of claim 14, in which the microprocessor is further configured to disconnect the at least one battery cell marked as faulty.

20. The apparatus of claim 14, in which the plurality of battery cells and the microprocessor comprises a battery pack system module.