Secondary battery

• US 20060093896A1
• Filed: 08/25/2005
• Published: 05/04/2006
• Est. Priority Date: 10/28/2004
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Kwak, Yoon-Tai, Hong, Eui-Sun
• Granted Patent: US 8,691,408 B2
• Time in Patent Office: Days
• US Class Current: 429/61
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 50/578 in response to pressure
• CPC Class Codes: H01M 50/583 in response to current, e.g. fuses
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A secondary battery includes a case having positive and negative electrodes, a safety device attached to a surface of the case and having a resistance value which changes during swelling of the case, and a protective circuit module attached to a side of the case while being electrically connected to the safety device. The resistance value of the safety device changes as the case swells, and the protective circuit module reduces or interrupts charging/discharging currents in response thereto. The safety device can be used for all secondary batteries regardless of capacity, can quickly react against abruptly rising internal temperature and rapid swelling, and can stably prevent swelling which occurs above an allowable temperature.

Claims

1. A secondary battery, comprising:

a case having positive and negative electrodes adapted to pass charging and discharging currents; and

a safety device attached to a surface of the case and adapted to change its electrical resistance in response to swelling of the case.

2. The secondary battery as claimed in claim 1, further comprising a protective circuit module attached to a side of the case, the protective circuit module being electrically connected to the safety device and adapted to reduce charging/discharging currents in response to electrical resistance changes of the safety device.

3. The secondary battery as claimed in claim 1, wherein the case comprises a first region and a second region having an area smaller than that of the first region.

4. The secondary battery as claimed in claim 3, wherein the safety device is attached to the first region.

5. The secondary battery as claimed in claim 3, wherein the safety device is attached to the second region.

6. The secondary battery as claimed in claim 3, wherein the safety device is attached to a center of the first region.

7. The secondary battery as claimed in claim 3, wherein the safety device is attached to a center of the second region.

8. The secondary battery as claimed in claim 3, wherein the safety device is attached to an intersection of diagonal lines of the first region.

9. The secondary battery as claimed in claim 3, wherein the safety device is attached near a corner of the first region.

10. The secondary battery as claimed in claim 3, wherein the safety device is attached to an intersection of diagonal lines of the second region.

11. The secondary battery as claimed in claim 1, wherein the safety device is attached to a surface of the case using one of an adhesive, a double-faced adhesive tape, and a double-faced adhesive film.

12. The secondary battery as claimed in claim 1, wherein the safety device comprises:

an insulation film attached to a surface of the case;

a metal wire arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the metal wire.

13. The secondary battery as claimed in claim 1, wherein the safety device comprises:

an insulation film attached to a surface of the case;

a metal foil arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the metal foil.

14. The secondary battery as claimed in claim 1, wherein the safety device comprises:

an insulation film attached to a surface of the case;

a semiconductor strip formed on a surface of the insulation film; and

lead terminals respectively connected to both ends of the semiconductor strip.

15. The secondary battery as claimed in claim 1, wherein the safety device comprises a strain gauge.

16. The secondary battery as claimed in claim 2, further comprising a flexible wiring pattern adapted to connect the safety device to the protective circuit module.

17. The secondary battery as claimed in claim 16, wherein the flexible wiring pattern comprises:

a first insulation layer attached to a surface of the case;

a wiring pattern arranged on the first insulation layer; and

a second insulation layer adapted to cover the wiring pattern.

18. The secondary battery as claimed in claim 2, wherein the protective circuit module comprises at least one conductive terminal for electrical connection to the safety device.

19. The secondary battery as claimed in claim 2, wherein the protective circuit module comprises at least one conductive terminal for electrical connection to at least one of the positive and negative electrodes of the case.

20. The secondary battery as claimed in claim 2, further comprising an insulation resin ring arranged between the case and the protective circuit module and adapted to prevent them from being separated from each other.

21. The secondary battery as claimed in claim 1, wherein the case comprises a safety vent arranged on a surface thereof, the safety vent having a smaller thickness than that of the case.

22. A secondary battery, comprising:

a case of a conductive material, the case containing an electrode assembly having a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes therein together with an electrolyte, wherein a top opening of the case is adapted to be sealed by a cap plate;

a safety device attached to a surface of the case and adapted to change its electrical resistance in response to swelling of the case; and

a protective circuit module attached to a side of the case, the protective circuit module being electrically connected to the safety device and adapted to reduce charging/discharging currents in response to electrical resistance changes of the safety device.

23. The secondary battery as claimed in claim 22, wherein the case comprises:

first regions which are spaced apart and are parallel to each other;

second regions which have an area smaller that that of the first regions and which are spaced apart along a periphery of the first regions and are parallel to each other;

a third region arranged perpendicular to the first and second regions and adapted to cover a side of the first and second regions; and

a cap plate attached to the case and positioned opposite to the third region and perpendicular to the first and second regions and having an electrode terminal arranged on a surface thereof.

24. The secondary battery as claimed in claim 23, wherein the safety device is attached to at least one of the first regions.

25. The secondary battery as claimed in claim 23, wherein the safety device is attached to at least one of the second regions.

26. The secondary battery as claimed in claim 24, wherein the safety device is attached to a center of at least one of the first regions.

27. The secondary battery as claimed in claim 25, wherein the safety device is attached to a center of at least one of the second regions.

28. The secondary battery as claimed in claim 23, wherein the safety device is attached to an intersection of diagonal lines of at least one of the first regions.

29. The secondary battery as claimed in claim 23, wherein the safety device is attached near a corner of at least one of the first regions.

30. The secondary battery as claimed in claim 25, wherein the safety device is attached to an intersection of diagonal lines of at least one of the second regions.

31. The secondary battery as claimed in claim 22, wherein the safety device is attached to a surface of the case using one of an adhesive, a double-faced adhesive tape, and a double-faced adhesive film.

32. The secondary battery as claimed in claim 22, wherein the safety device comprises:

an insulation film attached to a surface of the case;

a metal wire arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the metal wire.

33. The secondary battery as claimed in claim 22, wherein the safety device comprises:

an insulation film attached to a surface of the case;

a metal foil arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the metal foil.

34. The secondary battery as claimed in claim 22, wherein the safety device comprises:

an insulation film attached to a surface of the case;

a semiconductor strip arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the semiconductor strip.

35. The secondary battery as claimed in claim 22, wherein the safety device comprises a strain gauge.

36. The secondary battery as claimed in claim 22, further comprising a flexible wiring pattern adapted to connect the safety device to the protective circuit module.

37. The secondary battery as claimed in claim 36, wherein the flexible wiring pattern comprises:

a first insulation layer attached to a surface of the case;

a wiring pattern arranged on the first insulation layer; and

a second insulation layer adapted to cover the wiring pattern.

38. The secondary battery as claimed in claim 22, wherein the protective circuit module comprises at least one conductive terminal for electrical connection to the safety device.

39. The secondary battery as claimed in claim 22, wherein the protective circuit module comprises at least one conductive terminal for electrical connection to at least one of the electrode terminal and the case.

40. The secondary battery as claimed in claim 22, further comprising an insulation resin ring arranged between the case and the protective circuit module and adapted to prevent them from being separated from each other.

41. The secondary battery as claimed in claim 22, wherein the case comprises a safety vent arranged on the third region, the safety vent having a smaller thickness than that of the case.

42. A secondary battery, comprising:

an external terminal connected to one of an external charger or load;

a bare cell adapted to respectively accumulate energy or release stored energy in a charging or discharging mode;

a charging/discharging FET device connected to a large-current path between the external terminal and the bare cell;

a resistance sensor adapted to sense the current of the bare cell;

a safety device attached to a surface of the bare cell and adapted to sense swelling of the bare cell; and

a protective circuit adapted to control the charging/discharging FET device in response to values sensed from the bare cell, the resistance sensor, and the safety device.

43. The secondary battery as claimed in claim 42, wherein the safety device comprises:

an insulation film attached to a surface of the bare cell;

a metal foil arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the metal foil.

44. The secondary battery as claimed in claim 42, wherein the safety device comprises:

an insulation film attached to a surface of the bare cell;

semiconductor strip arranged on a surface of the insulation film; and

lead terminals respectively connected to both ends of the semiconductor strip.

45. The secondary battery as claimed in claim 42, wherein the safety device comprises a strain gauge attached to a surface of the bare cell.

46. The secondary battery as claimed in claim 42, wherein the protective circuit is adapted to turn the charging/discharging FET device off to interrupt the large-current path in response to the safety device sensing that the bare cell has swollen above a reference value.

47. The secondary battery as claimed in claim 42, wherein the protective circuit is adapted to turn the charging/discharging FET device off to interrupt the large-current path in response to the safety device sensing that the current of the bare cell is above or below a reference value or when the bare cell senses that its voltage is above or below a reference value.

48. The secondary battery as claimed in claim 46, wherein the protective circuit is adapted to turn the charging/discharging FET device off to interrupt the large-current path in response to the safety device sensing that the current of the bare cell is above or below a reference value or when the bare cell senses that its voltage is above or below a reference value.