Current collector for lithium electrode

• US 6,893,772 B2
• Filed: 04/28/1998
• Issued: 05/17/2005
• Est. Priority Date: 11/19/1993
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Howard, William G.
• Primary Examiner(s): Crepeau, Jonathan
• Application Number:
  US09/067,208
• Publication Number:
  US 20010008725A1
• Time in Patent Office: 2,576 Days
• Field of Search: 429/60, 429/94, 429/211, 429/219, 429/233, 429/245, 429/136, 429/231.95
• US Class Current: 429/94
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/52 Removing gases inside the secondary cell, e.g. by absorption vent plugs or other mechanical arrangements for facilitating escape of gases H01M50/30
• CPC Class Codes: H01M 16/00 Structural combinations of different types of electrochemical generators
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/405 Alloys based on lithium
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/662 Alloys collectors of lead alloys H01M4/685
• CPC Class Codes: H01M 4/70 characterised by shape or form
• CPC Class Codes: H01M 4/72 Grids
• CPC Class Codes: H01M 4/74 Meshes or woven material; Expanded metal
• CPC Class Codes: H01M 4/742 perforated material
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/466 U-shaped, bag-shaped or folded
• CPC Class Codes: H01M 50/531 Electrode connections inside a battery casing
• CPC Class Codes: H01M 6/10 with wound or folded electrodes
• CPC Class Codes: H01M 6/16 with organic electrolyte H01M6/18 takes precedence
• 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 29/10 : Battery-grid making

Abstract

An electrochemical cell and corresponding electrode assembly are described in which an alkali metal anode and a cathode assembly are wound together in a unidirectional winding having substantially straight sides such that the winding will fit into a prismatic cell. The anode and cathode are preferably arranged in the winding to provide for even utilization of reactive material during cell discharge by placing cathode and anode material in close proximity throughout the electrode assembly in the proportions in which they are utilized. An anode current collector having a length or height shorter than at least one of the length or height of the cathode current collector or alkali metal strips operatively associated with the anode current collector is also described.

Claims

1. A coiled electrode assembly, comprising:

an elongated, relatively thin lithium anode member having a longitudinal anode length dimension; and

an electrically conductive metallic anode current collector coupled to said anode member, said current collector having a longitudinal current collector length dimension wherein said longitudinal current collector dimension is substantially less than the longitudinal anode length dimension, wherein said longitudinal current collector dimension comprises one of about;

40%, 50%, 60%, 70% and 80% the longitudinal anode length dimension.

2. The electrode assembly of claim 1, further comprising a cathode member spaced from the anode with a separator material disposed therebetween, wherein said cathode member comprises of at least a one of:

a solid reactive material, a binder material and a conductivity enhancer.

3. The electrode assembly of claim 2, wherein the solid reactive material comprises a silver vanadium oxide material.

4. The electrode assembly of claim 2, wherein the binder material further comprises a PTFE material.

5. The electrode assembly of claim 2, wherein the conductivity enhancer further comprises a conductive carbon.

6. The coiled electrode assembly of claim 1, further comprising:

a first layer of separator material forming a pocket around the anode assembly formed by folding a separator material sheet over a top edge of the alkali metal, conforming the separator material sheet to the anode assembly, and joining the separator material sheet to itself with a seal at a bottom edge of the anode assembly; and

wherein a second layer of separator material forms a pocket around a cathode member formed by a folded portion of a sheet of separator material, said folded portion conforming the sheet of separator material to the cathode member, and joining the sheet of separator material to itself with a seal at a bottom edge of the cathode member.

7. The electrode assembly of claim 1, wherein:

the anode current collector extends through the end segment of the elongated strip of alkali metal corresponding to an end segment of the anode assembly that when wound into the coil disposes at least a portion of the anode current collector in the outermost layer of the coil and through at least one inner anode assembly layer of the coil not constituting the innermost layer.

8. An assembly according to claim 1, wherein said anode member includes a plurality of perforations over at least a portion of a major surface thereof.

9. An assembly according to claim 1, further comprising at least one electrically conductive tab member coupled to a one of the anode member and the current collector.

10. An assembly according to claim 9, wherein said at least one electrically conductive tab member comprises two tabs and said two tabs are coupled to a common edge portion of the anode member or the current collector.

11. An assembly according to claim 9, wherein said at least one electrically conductive tab member a longitudinal tab dimension comprises and said dimension is approximately equivalent to the longitudinal current collector dimension.

12. An assembly according to claim 8, wherein said plurality of perforations of said anode member comprises one of a metallic screen and a metallic grid.

13. An assembly according to claim 1, wherein said current collector comprises a nickel material.

14. An assembly according to claim 1, wherein said current collector comprises a titanium material.

15. An assembly according to claim 1, wherein said current collector includes a height dimension and said height dimension is substantially less than a height dimension of said anode member.

20. An assembly according to claim 1 or claim 16, wherein said anode member is disposed on the outer wrap or outer layer in a spirally wound electrochemical cell.

16. A coiled electrode assembly, comprising:

an elongated, relatively thin lithium anode member having a longitudinal anode length dimension; and

an electrically conductive metallic anode current collector coupled to said anode member, said current collector having a longitudinal current collector length dimension wherein said longitudinal current collector dimension is substantially less than the longitudinal anode length dimension, wherein said longitudinal current collector dimension comprises one of about;

5%, 10%, 15%, 20%, and 30% the longitudinal anode length dimension.

17. The electrode assembly of claim 16, wherein the anode current collector is formed from at least a one of:

a titanium material, a nickel material, a copper material, an alloy of at least a one of the foregoing materials.

18. The electrode assembly of claim 16, further comprising a cathode current collector comprising a titanium element.

19. The electrode assembly of claim 17, wherein the anode current collector further comprises a perforated element.