Tab surface treatments for polymer-metal laminate electrochemical cell packages

• US 20030031926A1
• Filed: 06/13/2002
• Published: 02/13/2003
• Est. Priority Date: 06/13/2001
• Status: Abandoned Application

• Current Assignee: PolyStor Corp.
• Original Assignee: PolyStor Corp.
• Inventors: Wang, Hongpeng, Farmer, Joseph, Nagarajan, Gowri
• Application Number:
  US10/171,509
• Publication Number:
  US 20030031926A1
• Time in Patent Office: Days
• US Class Current: 429/176
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/121 Organic material
• CPC Class Codes: H01M 50/124 having a layered structure
• CPC Class Codes: H01M 50/129 with two or more layers of only organic material
• CPC Class Codes: H01M 50/176 for prismatic or rectangular cells H01M50/181 takes precedence
• 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 50/50 Current conducting connections for cells or batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

Provided are alternative fabrication methods and compositions for an electrochemical cell. The methods of the present invention are applicable to the manufacture of polymer-cased lithium-ion secondary battery cells. Briefly, electrochemical cell fabrication techniques and articles that enhance the adhesion of polymer-metal laminate packaging materials and components to conductive leads (tabs) to thereby provide a reliable hermetic seal are provided. The tab surface treatments include chromate conversion coatings, phosphate conversion coatings, anodization, and surface cleaning.

Claims

1. A method of making an electrochemical cell, comprising:

preparing a conductive metal lead including surface-treating a metal lead material to increase at least one of hydrophobicity and polymer adhesion of the lead material surfaces;

preparing an electrochemical cell structure having said surface-treated conductive lead connected to an electrode and projecting from said structure;

placing the electrochemical cell structure in a polymer-metal laminate cell package, said lead projecting from an opening in said package;

optionally, interposing polymeric spacers between the lead and the polymer-metal laminate cell package; and

sealing said electrochemical structure in the polymer-metal laminate package, whereby a hermetic seal between the electrochemical cell polymer-metal laminate packaging material, optional spacer, and surface-treated lead protruding from the package is formed.

2. The method of claim 1, wherein the lead material is aluminum.

3. The method of claim 1, wherein the polymer-metal laminate package comprises a sheet of aluminum foil between sheets of polyolefin.

4. The method of claim 1, wherein the spacers are composed of polyolefin.

5. The method of claim 1, wherein the spacers are composed of cross-linked polypropylene.

6. The method of claim 1, wherein said cell is a lithium ion battery cell.

7. The method of claim 1, wherein said metal lead surface-treatment comprises formation of a chromate conversion coating.

8. The method of claim 1, wherein said metal lead surface-treatment comprises formation of a phosphate conversion coating.

9. The method of claim 2, wherein said metal lead surface-treatment comprises anodization.

10. The method of claim 1, wherein said metal lead surface-treatment comprises a surface cleaning.

11. The method of claim 10 wherein said surface cleaning uses sodium hydroxide as a cleaning agent.

27. The method of claim 7, wherein the thickness of said chromate conversion coating is between about 2 and 30 Angstroms.

28. The method of claim 7, wherein the thickness of said chromate conversion coating is between about 2 and 5 Angstroms.

29. The method of claim 7, wherein the thickness of said chromate conversion coating is about 3 Angstroms.

30. The method of claim 7, wherein the thickness of said chromate conversion coating produces a golden color on an aluminum metal lead surface.

32. The method of claim 1 wherein the treated lead has a peel strength of greater than twenty-five pounds when laminated to cross-linked polypropylene.

12. A polymer-metal laminate packaged electrochemical cell, comprising:

an electrochemical cell structure having a surface-treated metal lead connected to an electrode and projecting from said structure, wherein said surface-treated lead has at least one of increased hydrophobicity and polymer adhesion strength relative to an untreated lead of like composition; and

a polymer-metal laminate package enclosing said structure; and

optionally, polymeric spacers interposed between the lead and the polymer-metal laminate cell package;

wherein said packaged cell has a hermetic seal between the electrochemical cell polymer-metal laminate packaging material and the surface-treated lead protruding from the package.

13. The cell of claim 12, wherein the lead material is aluminum.

14. The cell of claim 12, wherein the polymer-metal laminate package comprises a sheet of aluminum foil between sheets of polyolefin.

15. The cell of claim 12, wherein the spacers are composed of polyolefin.

16. The cell of claim 12, wherein the spacers are composed of cross-linked polypropylene.

17. The cell of claim 12, wherein said cell is a lithium ion battery cell.

18. The cell of claim 12, wherein said metal lead surface-treatment comprises a chromate conversion coating.

19. The cell of claim 12, wherein said metal lead surface-treatment comprises a phosphate conversion coating.

20. The cell of claim 13, wherein said metal lead surface-treatment comprises anodization.

21. The cell of claim 12, wherein said metal lead surface-treatment comprises a surface cleaning.

31. The cell of claim 18, wherein the thickness of said chromate conversion coating produces a golden color on an aluminum metal lead surface.

33. The cell of claim 12 wherein the treated lead has a peel strength of greater than twenty-five pounds when laminated to cross-linked polypropylene.

22. An electrochemical cell current collector structure, comprising:

a metallic current collector;

a surface-treated metal lead conductively bonded to said current collector, said surface-treated lead having at least one of increased hydrophobicity and polymer adhesion strength relative to an untreated lead of like composition.

23. The structure of claim 22, wherein said lead material is aluminum.

24. The structure of claim 22, wherein said current collector material is aluminum.

25. The structure of claim 23, wherein said metal lead surface-treatment comprises a chromate conversion coating.

26. The structure of claim 25, wherein said chromate conversion coating has a golden color.