Response to detection of an overcharge event in a series connected battery element

• US 9,343,911 B2
• Filed: 11/30/2012
• Issued: 05/17/2016
• Est. Priority Date: 11/30/2012
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: LePort, Francisco, Kohn, Scott Ira
• Primary Examiner(s): Dunn, Drew A
• Assistant Examiner(s): Robbins, Jerry D
• Application Number:
  US13/690,203
• Publication Number:
  US 20140152259A1
• Time in Patent Office: 1,264 Days
• Field of Search: 320/118
• US Class Current: 1/1
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A system and method for identifying and responding to exceptional charge events of series-connected energy storage elements can include: a first charge imbalance detection system monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality, said first charge imbalance detection system initiating a reduction of said charge imbalance using a first response modality; a second charge imbalance detection system monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality; and a remediation system initiating a response to said exceptional charge event using a second response modality different from said first response modality, said response decreasing a risk associated with said exceptional charge event.

Claims

1. A microprocessor-implemented response system for an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:

a first charge imbalance detection system monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality, said first charge imbalance detection system initiating a reduction of said charge imbalance using a first response modality;

a second charge imbalance detection system monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality, wherein said exceptional charge event includes an overcharge of a battery element during a charging event, wherein said first detection modality includes a measurement of a voltage level of each battery element of the plurality of battery elements establishing a plurality of voltage imbalances between individual ones of the plurality of battery elements, wherein said first response modality includes adjusting said voltage levels to reduce said plurality of voltage imbalances, and wherein said second detection modality includes a statistical evaluation of a parameter of each battery element; and

a remediation system initiating a response to said exceptional charge event using a second response modality different from said first response modality, said response decreasing a risk associated with said exceptional charge event, wherein said exceptional charge event is associated with a particular one battery element having a particular charge target and wherein said response includes a reduction of said particular charge target.

2. The microprocessor-implemented response system of claim 1 wherein said response further includes a suspension of said charging event.

3. The microprocessor-implemented response system of claim 1 wherein said response further includes setting a service flag.

4. The microprocessor-implemented response system of claim 1 wherein said response further includes activating a visual indicator.

5. The microprocessor-implemented response system of claim 1 wherein said response further includes inhibiting any charging event until the energy storage system is serviced.

8. The microprocessor-implemented response system of claim 1 wherein said exceptional charge event is associated with a particular one battery element having a particular charge storage capacity and wherein said response includes use of a response modality similar in operation to said first response modality to directly reduce a stored charge of said particular one battery element responsive to an assumed stored charge and a predetermined impedance electrically communicated to said particular one battery element for a time calculated to reduce said assumed stored charge to a predetermined fraction of said particular charge storage capacity.

9. The microprocessor-implemented response system of claim 8 wherein predetermined fraction is in the range of 50%+/−

10%.

10. The microprocessor-implemented response system of claim 1 wherein said charging event includes an associated maximum charge target and wherein said response further includes a reduction of said associated maximum charge target.

11. The microprocessor-implemented response system of claim 1 wherein said response further includes logging a set of data associated with said exceptional charge event.

13. The microprocessor-implemented response system of claim 1 wherein said particular one battery element has an associated gain factor used when charging said particular one battery element and wherein said response further includes a reduction to said associated gain factor.

14. The microprocessor-implemented response system of claim 1 wherein said particular one battery element has an associated voltage offset factor used when charging said particular one battery element and wherein said response further includes a reduction to said associated voltage offset factor.

6. A microprocessor-implemented response system for an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:

a first charge imbalance detection system monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality, said first charge imbalance detection system initiating a reduction of said charge imbalance using a first response modality;

a second charge imbalance detection system monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality, wherein said exceptional charge event includes an overcharge of a battery element during a charging event, wherein said first detection modality includes a measurement of a voltage level of each battery element of the plurality of battery elements establishing a plurality of voltage imbalances between individual ones of the plurality of battery elements, wherein said first response modality includes adjusting said voltage levels to reduce said plurality of voltage imbalances, and wherein said second detection modality includes a statistical evaluation of a parameter of each battery element; and

a remediation system initiating a response to said exceptional charge event using a second response modality different from said first response modality, said response decreasing a risk associated with said exceptional charge event, wherein said exceptional charge event is associated with a particular one battery element having a particular charge storage capacity and wherein said response includes use of said first response modality to reduce a stored charge of said particular one battery element to a predetermined fraction of said particular charge storage capacity intentionally creating an imbalance.

7. The microprocessor-implemented response system of claim 6 wherein predetermined fraction is in the range of 50%+/−

10%.

29. The microprocessor-implemented response system of claim 6, wherein said response further includes inhibiting any charging event until the energy storage system is serviced.

12. A microprocessor-implemented response system for an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:

a first charge imbalance detection system monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality, said first charge imbalance detection system initiating a reduction of said charge imbalance using a first response modality;

a second charge imbalance detection system monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality, wherein said exceptional charge event includes an overcharge of a battery element during a charging event, wherein said first detection modality includes a measurement of a voltage level of each battery element of the plurality of battery elements establishing a plurality of voltage imbalances between individual ones of the plurality of battery elements, wherein said first response modality includes adjusting said voltage levels to reduce said plurality of voltage imbalances, and wherein said second detection modality includes a statistical evaluation of a parameter of each battery element; and

a remediation system initiating a response to said exceptional charge event using a second response modality different from said first response modality, said response decreasing a risk associated with said exceptional charge event, wherein the energy storage system includes a thermal control system providing a temperature control of the plurality of battery elements responsive to a thermal profile and wherein said response includes a modification to said thermal profile actuating said thermal control system at an increased cooling capacity.

30. The microprocessor-implemented response system of claim 12, wherein said charging event includes an associated maximum charge target and wherein said response further includes a reduction of said associated maximum charge target.

15. A computer-implemented method to respond to an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:

monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality;

reducing said charge imbalance using a first response modality;

monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality, wherein said exceptional charge event is an overcharge of said particular one battery element; and

decreasing a risk associated with said exceptional charge event using a second response modality different from said first response modality, wherein said decreasing-risk step includes bleeding energy from said particular one battery element.

16. The method of claim 15 further comprising transferring energy to the plurality of series-connected battery elements from a charging station and wherein said decreasing-risk step further includes asserting a stop charging signal to said charging station and suspending said energy transferring.

17. The method of claim 16 further comprising setting an overcharge status flag whenever said overcharge is detected and wherein said stop charging signal remains asserted as long as said overcharge status flag remains set.

18. The method of claim 15 further comprising transferring energy to the plurality of series-connected battery elements from a charging station and wherein said decreasing-risk step further includes asserting a reduced charging signal to said charging station and limiting said energy transferring to prevent charging to 100% SOC.

19. The method of claim 18 further comprising setting an overcharge status flag whenever said overcharge is detected and wherein said reduced charging signal remains asserted as long as said overcharge status flag remains set.

20. The method of claim 15 wherein said decreasing-risk step further includes asserting a diagnostic trouble code when detecting said overcharge.

21. The method of claim 15 wherein said decreasing-risk step further includes providing a visual indication of said overcharge.

22. The method of claim 15 wherein said energy bleeding is not performed by said first response modality and includes assuming an SOC for said particular one battery element and selectively coupling a predetermined impedance to said particular one battery element to discharge energy from said particular one battery element at a rate responsive to said SOC until a calculated SOC responsive to said SOC and to said predetermined impedance reaches a predetermined SOC level.

23. The method of claim 15 wherein said particular one battery element includes an SOC charge target wherein said decreasing-risk step includes reducing said SOC charge target.

24. The method of claim 15 wherein the plurality of battery elements each includes an SOC charge target wherein said decreasing-risk step includes reducing said SOC charge target.

27. The method of claim 15 further comprising transferring coolant to the plurality of series-connected battery elements from a coolant system to effect a cooling operation of the plurality of series-connected battery elements and wherein said decreasing-risk step includes increasing said cooling operation to reduce a temperature of said particular one battery element.

28. The method of claim 15 further comprising transferring coolant to the plurality of series-connected battery elements from a coolant system to effect a cooling operation of the plurality of series-connected battery elements using a set of predetermined thermal setpoints and wherein said decreasing-risk step includes lowering one or more setpoints of said set of predetermined thermal setpoints to increase said cooling operation.

25. A computer-implemented method to respond to an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:

monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality;

reducing said charge imbalance using a first response modality;

monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality, wherein said exceptional charge event is an overcharge of said particular one battery element; and

decreasing a risk associated with said exceptional charge event using a second response modality different from said first response modality, wherein said particular one battery element includes an adjustment profile including one or more of voltage gain and voltage offset factors and wherein said decreasing-risk step includes adjusting said adjustment profile.

31. The method of claim 25, further comprising transferring coolant to the plurality of series-connected battery elements from a coolant system to effect a cooling operation of the plurality of series-connected battery elements and wherein said decreasing-risk step includes increasing said cooling operation to reduce a temperature of said particular one battery element.

26. A computer-implemented method to respond to an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:

monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality;

reducing said charge imbalance using a first response modality;

monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality, wherein said exceptional charge event is an overcharge of said particular one battery element; and

decreasing a risk associated with said exceptional charge event using a second response modality different from said first response modality, wherein the plurality of battery elements each includes an adjustment profile including one or more of voltage gain and voltage offset factors and wherein said decreasing-risk step includes adjusting said adjustment profiles.

32. The method of claim 26, further comprising transferring coolant to the plurality of series-connected battery elements from a coolant system to effect a cooling operation of the plurality of series-connected battery elements using a set of predetermined thermal setpoints and wherein said decreasing-risk step includes lowering one or more setpoints of said set of predetermined thermal setpoints to increase said cooling operation.