Sealed secondary cell

• US 5,856,041 A
• Filed: 10/21/1996
• Issued: 01/05/1999
• Est. Priority Date: 10/20/1995
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ito, Noboru, Hamada, Shinji, Inoue, Hiroshi, Ikoma, Munehisa
• Primary Examiner(s): Maples, John S.
• Application Number:
  US08/734,341
• Time in Patent Office: 806 Days
• Field of Search: 429/181, 429/182, 429/184
• US Class Current: 429/182
• CPC Class Codes: H01M 50/176 for prismatic or rectangular cells H01M50/181 takes precedence
• CPC Class Codes: H01M 50/184 characterised by their shape or structure
• CPC Class Codes: H01M 50/188 the sealing members being arranged between the lid and terminal
• CPC Class Codes: H01M 50/193 Organic material
• CPC Class Codes: H01M 50/503 characterised by the shape of the interconnectors
• CPC Class Codes: H01M 50/517 by fixing means, e.g. screws, rivets or bolts
• CPC Class Codes: H01M 50/55 on the same side of the cell
• CPC Class Codes: H01M 50/553 Terminals adapted for prismatic, pouch or rectangular cells
• CPC Class Codes: H01M 50/562 characterised by the material
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A sealed secondary cell maintaining enclosed property and battery performance for a long period in a wide range of environments of use including high temperature, high humidity, and vibration is presented. A terminal pole is composed of a current collector, a flange with a flat top surface, and a pole formed on the flange upper surface projecting at right angle, a rotation arresting portion of the terminal pole is formed by the flange and lower side of a lid, an annular packing is disposed between the flange upper surface and lid lower side so as to surround the pole, an annular pressing spring is pressed in from above the pole, the annular packing interposed between the flange upper surface and lid lower side is compressed in the vertical direction by the elastic force of the annular pressing spring, the annular pressing spring is stopped on the outer circumferential edge of the pole at a position for sealing and fixing the terminal pole in the lid, and thereby the battery jar is enclosed.

Claims

1. A sealed secondary cell comprising:

a battery jar having an opening;

a plate group having at least one positive plate and at least one negative plate disposed in the battery jar;

electrolyte impregnated in the plate group;

a lid jar having a lower side disposed so as to cover the opening of the battery jar, the lid having at least one hole; and

a terminal pole fixed to the lid and disposed through the at least one hole and electrically connected to at least one plate of the plate group, the terminal pole comprising

i) a flange positioned at the lower side of the lid which has a first upper surface, a second upper surface forming an annular groove in said first upper surface, and a lower surface;

ii) a pole projecting vertically from the first upper surface of the flange through the hole in the lid; and

iii) a current collector on the lower surface of the flange and connected to the at least one plate;

an annular pressing spring having an opening with an inner diameter smaller than a maximum outer diameter of the terminal pole;

wherein the terminal pole has stopping means in at least a part of an outer circumference which engages the opening of the annular pressing spring; and

an annular packing surrounding the terminal pole and disposed within said annular groove and between the second upper surface of the flange and the lower side of the lid, the annular packing being compressed in the vertical direction by an elastic force exerted by the annular pressing spring such that the second upper surface of the flange and the lower side of the lid are sealed by the annular packing.

2. A sealed secondary cell of claim 1,

wherein the flange has an engagement portion,

the lid has a rotation preventive portion, and

the engagement portion and the rotation preventive portion are engaged with each other, thereby forming a rotation arresting portion of the terminal pole.

3. A sealed secondary cell of claim 2,

wherein one of the engagement portion and rotation preventive portion is concave, and the other is convex, and

the convex portion and the concave portion are engaged with each other to form the rotation preventive portion.

4. A sealed secondary cell of claim 2,

wherein the flange has at least one linear side as the engagement portion,

the lid has a side with a protruding portion projecting inside of the battery jar, and

the negative plate possesses at least one of nickel and iron, and the electrolyte is an alkaline electrolyte.

5. A sealed secondary cell of claim 1,

wherein the stopping means is a biting flaw formed on the outer circumference of the pole when pressing in the pressing spring, and

an inner circumference of the opening of the annular pressing spring is stopped so as to be engaged with the biting flaw of the pole.

6. A sealed secondary cell of claim 1,

wherein an inner periphery of the annular pressing spring forms a cut having an end surface of right angle or acute angle, and

the cut is stopped in the biting flaw of the pole.

7. A sealed secondary cell of claim 1,

wherein an inner periphery of the annular pressing spring forms plural cuts, and

the plural cuts facilitate press-fitting of the annular pressing spring into the pole, and work to compress uniformly on the whole circumference of the annular packing.

8. A sealed secondary cell of claim 1,

wherein the annular pressing spring is formed of a flat outer circumference, an inner circumference having the opening, and a slope between the outer circumference and inner circumference,

a notch or a cut is formed in the inner circumference and slope, and

the notch or cut adjusts the pressing force of the pressing spring.

9. A sealed secondary cell of claim 1,

wherein the annular pressing spring forms a slope between an inner circumference having the opening and the outer circumference,

a notch or a cut is formed in at least one selected from the group consisting of the inner circumference, outer circumference, and slope, and

the notch or cut adjusts the pressing force of the pressing spring.

10. A sealed secondary cell of claim 1,

wherein a surface hardness of the pole of the terminal pole is smaller than a hardness of an end portion of the opening of the annular pressing spring, by 100 Hv or more as Vickers hardness, and

the surface hardness of the pole is in a range of Hv 150 to Hv 350.

11. A sealed secondary cell of claim 10,

wherein a surface of the pole of the terminal pole is covered with a metal material.

12. A sealed secondary cell of claim 11,

wherein the metal material contains at least nickel.

13. A sealed secondary cell of claim 1,

wherein the inner diameter of the opening of the annular pressing spring is 0.05 mm to 0.4 mm smaller than the maximum outer diameter of the pole at a stopping position of the annular pressing spring.

14. A sealed secondary cell of claim 1,

wherein the stopping means is an annular groove formed on the outer circumference of the pole, and

the opening of the annular pressing spring is stopped in this groove.

15. A sealed secondary cell of claim 14,

wherein the depth of the groove is 0.02 mm to 0.1 mm.

16. A sealed secondary cell of claim 1,

wherein the stopping means is an annular step formed on the outer circumference of the pole, and

the opening of the annular pressing spring is stopped in this step.

17. A sealed secondary cell of claim 16,

wherein the depth of the step is 0.02 mm to 0.1 mm.

18. A sealed secondary cell of claim 1,

wherein the pressing force of the pressing spring applied between the second upper surface of the flange and the lower side of the lid is in a range of 50 kgf to 600 kgf.

19. A sealed secondary cell of claim 1,

wherein a sealing agent is composed between the second upper surface of the flange and the lower side of the lid,

the sealing agent is made of a flowable material, and

the lid and the flange are sealed by the annular packing and the sealing agent.

20. A sealed secondary cell of claim 19,

wherein the sealing agent is placed around the annular packing.

21. A sealed secondary cell of claim 19,

wherein the sealing agent contains at least one principal ingredient selected from the group consisting of asphalt pitch, fluoroplastic elastomer, and silicone resin.

22. A sealed secondary cell of claim 1,

wherein the annular packing is an O-ring having at least one sectional shape of nearly circular shape and nearly polygonal shape.

23. A sealed secondary cell of claim 1,

wherein the annular packing is composed of at least one selected from the group consisting of ethylene propylene rubber, nitrile rubber, butyl rubber, silicone rubber, and fluoro rubber.

24. A sealed secondary cell of claim 1,

wherein the current collector forms a convex portion extended in the horizontal direction from one end of the flange, and

one plate of the positive plate and negative plate is connected to this convex portion.

25. A sealed secondary cell of claim 1,

wherein the current collector forms a convex portion extended in the horizontal direction with a step from one end of the flange, and one plate of the positive plate and negative plate is connected to this convex portion.

26. A sealed secondary cell of claim 1,

wherein the current collector is formed at a lower side of the flange.

27. A sealed secondary cell of claim 1,

wherein the pole has an upper surface having a flat plane, and a female thread formed on the upper surface.

28. A sealed secondary cell of claim 27, further comprising:

a coupling plate for coupling other cells,

wherein one end of the coupling plate is overlaid on the flat plane, and

the coupling plate is fixed by the female thread and male threads inserted into the female thread.

29. A sealed secondary cell of claim 1,

wherein the pole has a male thread formed on its upper surface,

an outer diameter of the male thread is smaller than an outer diameter of the pole, and a base of the male thread has a step of a flat plane parallel to a direction of diameter of the pole.

30. A sealed secondary cell of claim 29, further comprising:

a coupling plate for coupling other cells,

wherein one end of the coupling plate is overlaid on the flat plane, and the coupling plate is fixed by the male thread and a nut fixed by inserting the male thread.

31. A sealed secondary cell of claim 1,

wherein the plate group is composed of plural positive plates and negative plates separated mutually by separators,

the plate group impregnates the electrolyte,

the positive plate possesses an active substance of nickel compound,

the negative plate possesses at least one of cadmium and hydrogen occlusion alloy, and

the electrolyte is an alkaline electrolyte.

32. A sealed secondary cell of claim 1,

wherein the positive plate possesses one active substance selected from the group consisting of lithium hydroxide, manganese dioxide, molybdenum sulfide, and polyaniline,

the negative plate possesses lithium, and

the electrolyte possesses non-protonic organic solvent and lithium salt.

33. A sealed secondary cell of claim 1,

wherein the positive plate possesses an aluminum compound,

the negative plate possesses at least one of nickel and iron, and the electrolyte is an alkaline electrolyte.

34. A terminal pole for use in a sealed secondary cell comprising:

a flange which has a first upper surface, a second upper surface forming an annular groove in the first upper surface, and a lower surface;

a pole projecting vertically from the first upper surface of the flange; and

current collector on the lower surface of the flange.

35. The terminal pole of claim 34, wherein the flange further comprises an engagement portion for engaging a rotation preventive portion, of a battery lid to form a rotation arresting portion of a battery terminal pole.

36. The terminal pole of claim 34, wherein the flange further comprises a concave engagement portion for engaging a convex rotation preventive portion of a battery lid to form a rotation arresting portion of a battery terminal pole.

37. The terminal pole of claim 34, wherein the flange further comprises a convex engagement portion for engaging a concave rotation preventive portion of a battery lid to form a rotation arresting portion of a battery terminal pole.

38. The terminal pole of claim 35, wherein the engagement portion of the flange has at least one linear side for engaging a side projection inside the battery lid.

39. The terminal pole of claim 34, further comprising stopping means in at least a part of an outer circumference of the pole for engaging an opening in an annular pressing spring.