Closure vent seal and assembly

• US 20060228620A1
• Filed: 06/08/2006
• Published: 10/12/2006
• Est. Priority Date: 04/28/2004
• Status: Active Grant

• Current Assignee: Eveready Battery Company Incorporated (Energizer Holdings, Inc.)
• Original Assignee: Eveready Battery Company Incorporated (Energizer Holdings, Inc.)
• Inventors: Wu, James X., Langan, Richard A., Martinson, Jeannine L.
• Granted Patent: US 7,833,647 B2
• Time in Patent Office: Days
• US Class Current: 429/56
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2200/106 PTC
• CPC Class Codes: H01M 50/152 for cells having curved cross-section, e.g. round or elliptic H01M50/15, H01M50/153 take precedence
• CPC Class Codes: H01M 50/167 by crimping
• CPC Class Codes: H01M 50/171 using adhesives or sealing agents
• CPC Class Codes: H01M 50/3425 in the form of rupturable membranes or weakened parts, e.g. pierced with the aid of a sharp member
• CPC Class Codes: H01M 50/534 characterised by the material of the leads or tabs
• CPC Class Codes: H01M 50/538 Connection of several leads or tabs of wound or folded electrode stacks
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

A closure assembly and rupturable vent seal adapted for use in an electrochemical battery cell is disclosed. The vent seal includes a series of peripheral projections that can be folded to insure proper sealing of the vent without wrinkles or overlapping folded portions. Methods of accomplishing the invention are also contemplated.

Claims

1. A vent closure seal for an electrochemical cell container, said vent closure seal comprising:

a planar member having a central point, said planar member adapted to create a rupturable vapor seal for a cylindrical electrochemical cell container; and

wherein the planar member includes at least one protruding portion which extends a greater distance from the central point relative to a non-protruding portion of the planar member.

2. A vent closure seal according to claim 1 wherein there is a plurality of protruding portions and wherein the protruding portions are spaced at a distance apart along a peripheral edge of the planar member so that, when each protruding portion is at least partially folded back towards the central point along the periphery, none of the folded protruding portions overlap.

3. A vent closure seal according to claim 1 wherein the protruding portion has a peripheral shape selected from the group consisting of:

a sawtooth, a concave parabola, a convex parabola and a multi-sided polygon shape.

4. A vent closure seal according to claim 3 wherein there is a plurality of protruding portions and each protruding portion has a substantially identical shape.

5. A vent closure seal according to claim 3 wherein there is a plurality of protruding portions and at least two of said protruding portions have differing shapes.

6. A vent closure seal according to claim 3 wherein the protruding portions are spaced at a distance apart along a peripheral edge of the laminar member so that, when each protruding portion is at least partially folded back towards the central point along the periphery, none of the folded protruding portions overlap.

7. A vent closure seal according to claim 1 wherein said member comprises a plurality of laminar members stacked in a planar configuration.

8. A vent closure seal according to claim 7 wherein a metal foil laminar member is disposed between a polymeric material laminar member and an adhesive laminar member.

9. A vent closure seal according to claim 7 wherein at least one laminar member is made from a material selected from the group consisting of:

a vapor barrier, an adhesive and polymeric material.

10. A vent closure seal according to claim 7 wherein at least one laminar member is made from a material selected from the group consisting of:

polypropylene, polyethylene, a non-metallized film coated with an oxidized material, an aluminum-based foil and combinations thereof.

11. A method for making and sealing an electrochemical cell, said method comprising:

providing a vent member, an inner header ring and a cylindrical electrochemical cell container with an open end;

wherein the electrochemical cell container is constructed to retain an anode, a cathode and an electrolyte;

wherein the inner header ring is selected to have a defined header diameter and a shaped aperture; and

wherein the vent member has a periphery, matching the shaped aperture to create a vapor barrier, and at least one protruding portion, extending radially beyond the non-protruding portion;

creating a cell closure by positioning the inner header ring proximate to the vent member and crimping the protruding portions without causing wrinkles in the vent member so that the aperture is sealed;

positioning the cell closure proximate to the open end to create electrically contact between the cell closure and one of;

the anode or the cathode; and

sealing the cell closure to the electrochemical cell container.

12. A method according to claim 11 further comprising providing an outer header ring, said outer header ring is selected to conform to the inner header ring, and wherein the creating a cell closure step includes positioning the vent foil so that the protruding portions are crimped between the inner and outer header rings.

13. A method according to claim 12 wherein the sealing the cell closure and electrochemical cell container step includes applying at least one of heat, pressure and ultrasonic energy to the outer header ring.

14. A method according to claim 12 wherein the outer header ring includes sidewalls of a defined length and wherein the protruding portion extends radially beyond non-protruding portion of the vent member for a distance of no more than one-half of the defined length of the sidewall.

15. A method according to claim 12 further comprising providing at least one gasket and wherein the creating a cell closure step includes positioning the gasket between the inner header ring and the outer header ring.

16. A method according to claim 11 wherein the sealing the cell closure and electrochemical cell container step includes applying at least one of heat, pressure and ultrasonic energy.

17. A method according to claim 11 wherein the sealing the cell closure and electrochemical cell container step includes mechanically compressing the cell closure and the electrochemical cell container.

18. A method according to claim 17 further comprising providing a gasket and wherein the creating a cell closure step includes positioning the gasket proximate to the inner header ring so as to enhance the mechanical compressing during the sealing the cell closure step.

19. A vent closure seal assembly for an electrochemical cell container, said assembly comprising:

a closure cup having an aperture to allow electrochemical reaction gas to flow therethrough;

a contact member having a defined peripheral shape;

a rupturable vent fixed between the closure cup and the contact member to selectively control the flow electrochemical reaction gas through the assembly, said rupturable vent having a peripheral shape that is not the same as the defined peripheral shape of the contact member;

wherein a first diameter of the rupturable vent is equal to a corresponding first diameter of the defined peripheral shape of the contact member along a first common planar axis;

wherein a second diameter of the rupturable vent is greater than a corresponding second diameter of the defined peripheral shape of the contact member along a second common planar axis; and

wherein the first and second common planar axes intersect at a center point of said contact member.

20. An assembly according to claim 19 wherein the vent is not rectangular in shape and a plurality of planar protrusions are integrated along a peripheral edge of the rupturable vent.

21. An assembly according to claim 20 wherein the planar protrusions have substantially the same size and shape, the closure cup includes a sidewall with a defined length and the planar protrusions extend radially beyond non-protruding portions of the rupturable vent for a distance of no more than one-half of the defined length of the sidewall.

22. An assembly according to claim 19 wherein the rupturable vent is held within the closure cup by mechanical compression.

23. An assembly according to claim 22 wherein the mechanical compression comprises a peripheral crimp causing the rupturable vent to create a sealed contact with the contact member in at least two separate spatial planes.

24. An assembly according to claim 19 wherein the rupturable vent is adhesively held within the closure cup.

25. An assembly according to claim 24 wherein the rupturable vent is also held within the closure cup by mechanical compression.

26. An assembly according to claim 25 wherein the mechanical compression comprises a peripheral crimp causing the rupturable vent to create a sealed contact with the contact member in at least two spatial planes.

27. An assembly according to claim 19 wherein the rupturable vent is a laminate including a metal foil, an adhesive and polymeric material.

28. An assembly according to claim 27 wherein the layers are arranged so that the polymeric material is proximate to the contact member and the metal foil is disposed between the polymeric material and the adhesive.

29. An assembly according to claim 19 wherein the rupturable vent comprises aluminum.

30. An assembly according to claim 19 wherein the rupturable vent comprises an adhesive.

31. An assembly according to claim 19 wherein the rupturable vent comprises a polymer.

32. An assembly according to claim 19 further comprising a gasket positioned proximate to the contact member.

33. A vent closure seal for an electrochemical cell container, said vent closure seal comprising:

a substantially circular disc having a circumference, said disc constructed from a material that will selectively rupture upon exposure to a predetermined pressure of electrochemical reaction gases; and

at least one projection integrated along the circumference and extending radially outward from the circular disc.

34. A vent closure seal according to claim 33 wherein the projection has a first edge, proximate to a portion of the circumference and defined by an arc that conforms to the portion of the circumference, and a second edge, forming a non-circular outermost periphery of the vent closure seal and defined by a shape selected from the group consisting of:

a sawtooth, a concave parabola, a convex parabola, a multi-sided polygon shape and a curved irregular shape.

35. A vent closure seal according to claim 33 wherein there are multiple projections, each projection having a substantially identical shape.

36. A vent closure seal according to claim 33 wherein there are multiple projections, each projection having a different shape.

37. A vent closure seal according to claim 33 wherein there are multiple projections and wherein each projection is spaced along the circumference so that, when any projection is at least partially folded along the circumference in any plane that is not parallel to the circular disc, a single folded projection will not touch any other folded projection.

38. A vent closure seal according to claim 33 wherein said disc comprises a plurality of laminar members stacked in a planar configuration.

39. A vent closure seal according to claim 38 wherein at least one laminar member is made from a material selected from the group consisting of:

a vapor barrier, an adhesive and polymeric material.

40. A vent closure seal according to claim 39 wherein a metal foil laminar member is disposed between a polymeric material laminar member and an adhesive laminar member.

41. A vent closure seal according to claim 39 wherein at least one laminar member is made from a material selected from the group consisting of:

polypropylene, polyethylene, a polyolefin other than polypropylene and polyethylene, a non-metallized film coated with an oxidized material, an aluminum-based foil and a metal-based foil other than aluminum.

42. A method for making and sealing an electrochemical cell, said method comprising:

providing an electrochemical cell container, a header assembly and a vent member;

wherein the electrochemical cell container retains an anode, a cathode and an electrolyte and said electrochemical cell has an open end;

wherein the header assembly has an aperture with a defined shape; and

wherein the vent member is adapted to create a rupturable vapor seal across the aperture and said vent member has a periphery with at least one non-protruding portion that creates a vapor barrier across the aperture and at least one protruding portion extending radially beyond the non-protruding portion;

creating a cell closure by positioning the header assembly proximate to the vent member to seal the aperture and pressing the protruding portions against the header assembly along the periphery without any overlap of the folded protruding portions;

positioning the cell closure across the open end to create electrically contact between the cell closure and one of;

the anode or the cathode; and

sealing the cell closure to the electrochemical cell container.