System and methods for managing a degraded state of a capacitor system

• US 9,190,860 B2
• Filed: 11/13/2012
• Issued: 11/17/2015
• Est. Priority Date: 11/15/2011
• Status: Active Grant

• Current Assignee: UCAP Power, Inc.
• Original Assignee: Maxwell Technologies Incorporated (Tesla Inc.)
• Inventors: Wright, Carl David, Lynds, Robert Shaw, Miller, John Michael
• Primary Examiner(s): Tso, Edward
• Application Number:
  US13/675,924
• Publication Number:
  US 20130119923A1
• Time in Patent Office: 1,099 Days
• Field of Search: 320/107, 320/116, 320/118, 320/119, 320/132, 320/150, 320/166, 320/167
• US Class Current: 1/1
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

This disclosure provides systems, methods and apparatus for managing a capacitor system. In one aspect, an energy storage system includes a capacitor system, a charging circuit, and a controller. The capacitor system includes one or more capacitors. The charging circuit is configured to charge the capacitor system to a first target voltage. The controller is configured to detect a first condition and is programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage. The controller is programmed to provide a notification that the capacitor system is operating in a degraded state.

Claims

1. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the controller is configured to select the value of the second target voltage based upon a type of the first condition.

2. The energy storage system of claim 1, wherein the capacitor system comprises a capacitance between a range of approximately 200 farads to approximately 2500 farads.

3. The energy storage system of claim 1, wherein the type of the first condition is at least one of a broken and shorted wire within the capacitor system.

4. The energy storage system of claim 1, wherein the capacitor system comprises at least one sensor configured to detect the first condition, the sensor configured to communicate the first condition to the controller.

5. The energy storage system of claim 4, wherein the sensor is positioned on a capacitor to detect a temperature condition of the capacitor.

6. The energy storage system of claim 1, wherein the capacitor system comprises a capacitor bank comprising a plurality of capacitors.

7. The energy storage system of claim 6, further comprising a balancing circuit configured to balance a plurality of capacitor output voltages with respect to each other, each capacitor output voltage extending across each of the plurality of capacitors.

8. The energy storage system of claim 6, wherein the first target voltage is defined as the overall voltage across the capacitor bank.

9. The energy storage system of claim 1, wherein the charging circuit is configured to output a constant current.

10. The energy storage system of claim 1, wherein the charging circuit comprises a DC to DC converter.

11. The energy storage system of claim 1, wherein the second target voltage is greater than or equal to a voltage sufficient to activate a starter for an internal combustion engine.

12. The energy storage system of claim 1, wherein the notification comprises a detectable reduced performance in an additional system connected to the energy storage system.

13. The energy storage system of claim 12, wherein the notification comprises an audibly detectible change in the performance of a starter within the additional system.

14. The energy storage system of claim 1, wherein the notification comprises an indicator device configured to receive a discrete output from the controller.

15. The energy storage system of claim 14, wherein the indicator device is configured to provide an indicator light or sound.

16. The energy storage system of claim 1, wherein the controller is configured to detect a temperature of the one or more capacitors.

17. The energy storage system of claim 16, wherein the controller is programmed to adjust the first target voltage to a third target voltage that varies as a linear function of temperature when the detected temperature condition is between an upper temperature condition and a lower temperature condition.

18. The energy storage system of claim 17, wherein the controller is configured to charge the capacitor system to a fourth target voltage that is approximately constant when the detected temperature condition is at least one of less than or equal to the lower temperature condition and greater than or equal to the upper temperature condition.

19. The energy storage system of claim 17, wherein the controller is configured to adjust the first target voltage to a sloping linear function of the detected temperature an approximately constant first voltage when the detected temperature falls at or below the target upper temperature and an approximately constant second voltage when the detected temperature.

20. A method of operating a capacitor-based energy storage system, comprising:

providing a controller and a capacitor system comprising at least one capacitor;

charging the at least one capacitor in the capacitor system with a charging circuit to a first target voltage;

detecting a condition of the capacitor system with the controller;

determining whether to put the capacitor system in a degraded state based on the condition;

reducing the charge of the at least one capacitor to a second target voltage in response to the condition;

providing a notification that the at least one capacitor is charged to the second target voltage, and

balancing a plurality of capacitor output voltages with respect to each other, each capacitor output voltage extending across each of the plurality of capacitors.

21. The method of claim 20, wherein charging comprises charging the at least one capacitor with an approximately constant current.

22. The method of claim 20, wherein providing comprises providing a capacitor bank comprising a plurality of capacitors.

23. The method of claim 20, wherein detecting comprises detecting a change in voltage across at least one capacitor in the capacitor system.

24. The method of claim 23, wherein detecting comprises detecting a change in voltage due to at least one of a broken and shorted wire within the capacitor system.

25. The method of claim 20, wherein reducing comprises closing a switch within a balancing circuit.

26. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a temperature condition of the capacitor system, wherein the controller is programmed to charge the capacitor system to a second target voltage that varies as a function of temperature when the detected temperature condition is between an upper temperature condition and a lower temperature condition,

wherein the capacitor system comprises a plurality of capacitors, wherein the first target voltage is defined as a combined operating voltage across the plurality of capacitors.

27. The energy storage system of claim 26, wherein the controller is programmed to charge the capacitor system to a second target voltage that varies as a linear function of temperature when the detected temperature condition is between an upper temperature condition and a lower temperature condition.

28. The energy storage system of claim 26, wherein the controller is configured to charge the capacitor system to a third target voltage that is approximately constant when the detected condition is at least one of greater than or equal to the lower temperature condition or less than or equal to the upper temperature condition.

29. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the capacitor system comprises at least one sensor configured to detect the first condition, the sensor configured to communicate the first condition to the controller.

30. The energy storage system of claim 29, wherein the sensor is positioned on a capacitor to detect a temperature condition of the capacitor.

31. The energy storage system of claim 29, wherein the capacitor system comprises a capacitor bank comprising a plurality of capacitors and the energy storage system further comprises a balancing circuit configured to balance a plurality of capacitor output voltages with respect to each other, each capacitor output voltage extending across each of the plurality of capacitors.

32. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage;

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the capacitor system comprises a capacitor bank comprising a plurality of capacitors; and

a balancing circuit configured to balance a plurality of capacitor output voltages with respect to each other, each capacitor output voltage extending across each of the plurality of capacitors.

33. The energy storage system of claim 32, wherein the second target voltage is greater than or equal to a voltage sufficient to activate a starter for an internal combustion engine.

34. The energy storage system of claim 32, wherein the notification comprises an indicator device configured to receive a discrete output from the controller.

35. The energy storage system of claim 32, wherein the controller is configured to detect a temperature of the one or more capacitors.

36. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the second target voltage is greater than or equal to a voltage sufficient to activate a starter for an internal combustion engine.

37. The energy storage system of claim 36, wherein the capacitor system comprises at least one sensor configured to detect the first condition, the sensor configured to communicate the first condition to the controller.

38. The energy storage system of claim 37, wherein the sensor is positioned on a capacitor to detect a temperature condition of the capacitor.

39. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the notification comprises a detectable reduced performance in an additional system connected to the energy storage system.

40. The energy storage system of claim 39, wherein the notification comprises an audibly detectible change in the performance of a starter within the additional system.

41. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the notification comprises an indicator device configured to receive a discrete output from the controller.

42. The energy storage system of claim 41, wherein the sensor is positioned on a capacitor to detect a temperature condition of the capacitor.

43. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a first condition and programmed, in response to the first condition, to instruct the charging circuit to charge the capacitor system to a second target voltage that is less than the first target voltage, and to provide a notification that the capacitor system is operating in a degraded state,

wherein the controller is configured to detect a temperature of the one or more capacitors.

44. A method of operating a capacitor-based energy storage system, comprising:

providing a controller and a capacitor system comprising at least one capacitor;

charging the at least one capacitor in the capacitor system with a charging circuit to a first target voltage;

detecting a condition of the capacitor system with the controller;

determining whether to put the capacitor system in a degraded state based on the condition;

reducing the charge of the at least one capacitor to a second target voltage in response to the condition; and

providing a notification that the at least one capacitor is charged to the second target voltage,

wherein reducing comprises closing a switch within a balancing circuit.

45. The method of claim 44, wherein detecting comprises detecting a change in voltage across at least one capacitor in the capacitor system.

46. The method of claim 45, wherein detecting comprises detecting a change in voltage due to at least one of a broken and shorted wire within the capacitor system.

47. A method of operating a capacitor-based energy storage system, comprising:

providing a controller and a capacitor system comprising at least one capacitor;

charging the at least one capacitor in the capacitor system with a charging circuit to a first target voltage;

detecting a condition of the capacitor system with the controller;

determining whether to put the capacitor system in a degraded state based on the condition;

reducing the charge of the at least one capacitor to a second target voltage in response to the condition; and

providing a notification that the at least one capacitor is charged to the second target voltage,

wherein detecting comprises detecting a change in voltage across at least one capacitor in the capacitor system,

wherein detecting comprises detecting a change in voltage due to at least one of a broken and shorted wire within the capacitor system.

48. An energy storage system, comprising:

a capacitor system comprising one or more capacitors;

a charging circuit configured to charge the capacitor system to a first target voltage; and

a controller configured to detect a temperature condition of the capacitor system, wherein the controller is programmed to charge the capacitor system to a second target voltage that varies as a function of temperature when the detected temperature condition is between an upper temperature condition and a lower temperature condition,

wherein the controller is configured to charge the capacitor system to a third target voltage that is approximately constant when the detected condition is at least one of greater than or equal to the lower temperature condition or less than or equal to the upper temperature condition.

49. Energy storage system of claim 48, wherein the controller is programmed to charge the capacitor system to a second target voltage that varies as a linear function of temperature when the detected temperature condition is between an upper temperature condition and a lower temperature condition.