Method of making a multi-electrode double layer capacitor having single electrolyte seal and aluminum-impregnated carbon cloth electrodes

• US 6,451,073 B1
• Filed: 05/16/2000
• Issued: 09/17/2002
• Est. Priority Date: 10/07/1994
• Status: Expired due to Fees

• Current Assignee: Tesla Inc.
• Original Assignee: Maxwell Electronic Components Group Incorporated (Tesla Inc.)
• Inventors: Kolb, Alan C., Dispennette, John M., Blank, Edward, Farahmandi, C. Joseph
• Primary Examiner(s): NGUYEN, HA T
• Application Number:
  US09/573,443
• Time in Patent Office: 854 Days
• Field of Search: 29/250-- 2, 361/502-505, 361/517-520, 361/522
• US Class Current: 29/25.03
• CPC Class Codes: H01G 11/12 Stacked hybrid or EDL capacitors
• CPC Class Codes: H01G 11/28 arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
• CPC Class Codes: H01G 11/40 Fibres
• CPC Class Codes: H01G 11/72 specially adapted for integration in multiple or stacked hybrid or EDL capacitors
• CPC Class Codes: H01G 11/76 specially adapted for integration in multiple or stacked hybrid or EDL capacitors
• CPC Class Codes: H01G 11/82 Fixing or assembling a capacitive element in a housing, e.g. mounting electrodes, current collectors or terminals in containers or encapsulations
• CPC Class Codes: H01G 11/84 Processes for the manufacture of hybrid or EDL capacitors, or components thereof
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator is positioned against the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal. The height of the interleaved stack is somewhat greater than the inside height of the closed capacitor case, thereby requiring compression of the interleaved electrode stack when placed inside of the case, and thereby maintaining the interleaved electrode stack under modest constant pressure. The closed capacitor case is filled with an electrolytic solution and sealed. A preferred electrolytic solution is made by dissolving an appropriate salt into acetonitrile (CH₃CN). In one embodiment, the two parts of the capacitor case are conductive and function as the capacitor terminals.

Claims

1. A method of making a double layer capacitor comprising:

impregnating each of a plurality of carbon cloths with a metal;

forming a plurality of current collector foils, each of the plurality of current collector foils having a tab portion and a paddle portion;

bonding the tab portion of each of one half of the plurality of current collector foils to each other and to a first capacitor terminal, thereby forming a first plurality of bonded current collector foils;

bonding the tab portion of each of another half of the plurality of current collector foils to each other and to a second capacitor terminal, thereby forming a second plurality of bonded current collector foils;

forming, respectively, a first plurality of electrodes and a second plurality of electrodes by positioning respective ones of the plurality of metal impregnated carbon cloths against respective paddle portions of each of the first plurality of bonded current collector foils and respective others of the plurality of metal impregnated carbon cloths against respective paddle portions of each of the second plurality of bonded current collector foils, wherein each of the first and second plurality of electrodes comprises one of the plurality of bonded current collector foils and one of the plurality of metal impregnated carbon cloths;

interleaving the first plurality of electrodes and the second plurality of electrodes, thereby forming an interleaved electrode stack;

interposing a respective porous separator portion between each of said first plurality of electrodes and each of said second plurality of electrodes, wherein the respective porous separator portion is positioned between each of the first plurality of electrodes and the second plurality of electrodes wherein porous separator material electrically insulates adjacent ones of the ,first plurality of electrodes and the second plurality of electrodes for preventing electrical shorting against each other; and

saturating the interleaved electrode stack with an electrolytic solution.

2. The method in claim 1 wherein said saturating comprises saturating said interleaved electrode stack with said electrolytic solution having a prescribed solvent into which a specified amount of a prescribed salt has been dissolved to form ions, the ions being able to readily pass through pores of said porous separator portion.

3. The method of claim 1 wherein said impregnating of each of said plurality of carbon cloths further comprises impregnating each of said plurality of carbon cloths with said metal by spraying molten metal deep into a tow of a carbon fiber bundle, thereby reducing carbon to carbon contacts for decreasing a transverse resistance of the carbon fiber bundle.

4. The method of claim 1 further comprising controlling porosity of each of said plurality of carbon cloths during said impregnating.

5. The method of claim 1 wherein said impregnating of each of said plurality of carbon cloths includes impregnating each of said plurality of carbon cloths with said metal, said metal being selected from a group consisting of aluminum and titanium.

6. The method of claim 1 further comprising:

forming a plurality of porous separator sleeves using the porous separator material having been cut into strips prior to said interposing, wherein said interposing step comprises fitting each of the plurality of porous separator sleeves over respective ones of one of said second plurality of electrodes.

7. The method of claim 6 wherein said forming said plurality of porous separator sleeves further comprises sealing edges of each of said plurality of porous separator sleeves.

8. The method of claim 1 wherein said interposing of said respective porous separator portion comprises fitting each of a plurality of porous separator sleeves comprising a separator material selected from a group of separator materials consisting of porous polypropylene and porous polyethylene, over one of said second plurality of electrodes.

9. A method of packaging a double layer capacitor comprising:

providing a wrapped interleaved electrode stack comprising a plurality of interleaved metal impregnated carbon cloth electrodes, each of the plurality of interleaved metal impregnated carbon cloth electrodes electrically being insulated from adjacent ones of the plurality of interleaved metal impregnated carbon cloth electrodes by a porous separator material, an insulating material surrounding the wrapped interleaved electrode stack;

applying a modest constant pressure against the interleaved electrode stack;

filling a capacitor container with an electrolytic solution, thereby saturating the wrapped interleaved electrode stack placed therein with the electrolytic solution, the electrolytic solution comprising a prescribed solvent into which a specified amount of a prescribed salt has been dissolved to form ions, the ions being able to readily pass through pores of the porous separator material; and

sealing the capacitor container, thereby maintaining the wrapped interleaved electrode stack immersed within the electrolytic solution.

10. The method of claim 9 wherein said applying comprises:

placing said wrapped interleaved electrode stack within a double-ended elongated container; and

attaching a terminal at each end of the double-ended elongated container, one or both of the terminals having a fill hole.

11. The method of claim 9 wherein said applying comprises:

placing said wrapped interleaved electrode stack in between an upper conductive shell and a lower conductive shell; and

attaching the upper conductive shell and the lower conductive shell together, an interior dimension formed being smaller than a dimension of said wrapped interleaved electrode stack, thereby forcing said wrapped interleaved electrode stack to conform with the interior dimension.

12. A method of making a double layer capacitor comprising:

impregnating each of a plurality of carbon cloths with a metal;

wherein the metal retained on the plurality of metal impregnated carbon cloths is between 42 and 53 percent of the total weight of the metal impregnated carbon cloths;

forming a plurality of current collector foils, each of the plurality of current collector foils having a tab portion and a paddle portion;

bonding the tab portion of each of one half of the plurality of current collector foils to each other and to a first capacitor terminal, thereby forming a first plurality of bonded current collector foils;

bonding the tab portion of each of another half of the plurality of current collector foils to each other and to a second capacitor terminal, thereby forming a second plurality of bonded current collector foils;

forming, respectively, a first plurality of electrodes and a second plurality of electrodes by positioning respective ones of the plurality of metal impregnated carbon cloths against respective paddle portions of each of the first plurality of bonded current collector toils and respective others of the plurality of metal impregnated carbon cloths against respective paddle portions of each of the second plurality of bonded current collector foils, wherein each of the first and second plurality of electrodes comprises one of the plurality of bonded current collector foils and one of the plurality of metal impregnated carbon cloths;

interleaving the first plurality of electrodes and the second plurality of electrodes, thereby forming an interleaved electrode stack;

interposing a respective porous separator portion between each of said first plurality of electrodes and each of said second plurality of electrodes, wherein the respective porous separator portion is positioned between each of the first plurality of electrodes and the second plurality of electrodes wherein porous separator material electrically insulates adjacent ones of the first plurality of electrodes and the second plurality of electrodes for preventing electrical shorting against each other; and

saturating the interleaved electrode stack with an electrolytic solution.

13. The method of claim 12 wherein the metal retained on the plurality of metal impregnated carbon cloths is about 48 percent of the total weight of the metal impregnated carbon cloths.

14. The method of claim 12 wherein the metal retained on the plurality of metal impregnated carbon cloths is about 15 percent of the total weight of the metal impregnated carbon cloths and the electrolytic solution.

15. The method of claim 12 further comprising applying a modest constant pressure against the interleaved electrode stack.

16. The method of claim 15 wherein the modest constant pressure is between 5 pounds per square inch and 18 pounds per square inch.

17. The method of claim 15 wherein the modest constant pressure is about 10 pounds per square inch.

18. The method of claim 15 wherein the modest constant pressure is between 5 pounds per square inch and 18 pounds per square inch.

19. The method of claim 15 wherein the modest constant pressure is about 10 pounds per square inch.

20. The method in claim 12 wherein said saturating comprises saturating said interleaved electrode stack with said electrolytic solution having a prescribed solvent into which a specified amount of a prescribed salt has been dissolved to form ions, the ions being able to readily pass through pores of said porous separator portion.

21. The method of claim 12 wherein said impregnating of each of said plurality of carbon cloths further comprises impregnating each of said plurality of carbon cloths with said metal by spraying molten metal deep into a tow of a carbon fiber bundle, thereby reducing carbon to carbon contacts for decreasing a transverse resistance of the carbon fiber bundle.

22. The method of claim 12 further comprising controlling porosity of each of said plurality of carbon cloths during said impregnating.

23. The method of claim 12 wherein said impregnating of each of said plurality of carbon cloths includes impregnating each of said plurality of carbon cloths with said metal, said metal being selected from a group consisting of aluminum and titanium.

24. The method of claim 12 further comprising:

forming a plurality of porous separator sleeves using the porous separator material having been cut into strips prior to said interposing, wherein said interposing step comprises fitting each of the plurality of porous separator sleeves over respective ones of one of said second plurality of electrodes.

25. The method of claim 24 wherein said forming said plurality of porous separator sleeves further comprises sealing edges of each of said plurality of porous separator sleeves.

26. The method of claim 12 wherein said interposing of said respective porous separator portion comprises fitting each of a plurality of porous separator sleeves comprising a separator material selected from a group of separator materials consisting of porous polypropylene and porous polyethylene, over one of said second plurality of electrodes.

27. A method of making a double layer capacitor comprising:

impregnating each of a plurality of carbon cloths with a metal;

wherein between two-thirds and three-fourths of an available tow volume is filled in a bundle exposed at a surface of the plurality of carbon cloths;

forming a plurality of current collector foils, each of the plurality of current collector foils having a tab portion and a paddle portion;

bonding the tab portion of each of one half of the plurality of current collector foils to each other and to a first capacitor terminal, thereby forming a first plurality of bonded current collector foils;

bonding the tab portion of each of another half of the plurality of current collector foils to each other and to a second capacitor terminal, thereby forming a second plurality of bonded current collector foils;

forming, respectively, a first plurality of electrodes and a second plurality of electrodes by positioning respective ones of the plurality of metal impregnated carbon cloths against respective paddle portions of each of the first plurality of bonded current collector foils and respective others of the plurality of metal impregnated carbon cloths against respective paddle portions of each of the second plurality of bonded current collector foils, wherein each of the first and second plurality of electrodes comprises one of the plurality of bonded current collector foils and one of the plurality of metal impregnated carbon cloths;

interleaving the first plurality of electrodes and the second plurality of electrodes, thereby forming- an interleaved electrode stack;

interposing a respective porous separator portion between each of said first plurality of electrodes and each of said second plurality of electrodes, wherein the respective porous separator portion is positioned between each of the first plurality of electrodes and the second plurality of electrodes wherein porous separator material electrically insulates adjacent ones of the first plurality of electrodes and the second plurality of electrodes for preventing electrical shorting against each other; and

saturating the interleaved electrode stack with an electrolytic solution.

28. The method of claim 27 further comprising applying a modest constant pressure against the interleaved electrode stack.

29. The method of claim 27 wherein the modest constant pressure is between 5 pounds per square inch and 18 pounds per square inch.

30. The method of claim 27 wherein the modest constant pressure is about 10 pounds per square inch.

31. The method in claim 27 wherein said saturating comprises saturating said interleaved electrode stack with said electrolytic solution having a prescribed solvent into which a specified amount of a prescribed salt has been dissolved to form ions, the ions being able to readily pass through pores of said porous separator portion.

32. The method of claim 27 wherein said impregnating of each of said plurality of carbon cloths further comprises impregnating each of said plurality of carbon cloths with said metal by spraying molten metal deep into a tow of a carbon fiber bundle, thereby reducing carbon to carbon contacts for decreasing a transverse resistance of the carbon fiber bundle.

33. The method of claim 27 further comprising controlling porosity of each of said plurality of carbon cloths during said impregnating.

34. The method of claim 27 wherein said impregnating of each of said plurality of carbon cloths includes impregnating each of said plurality of carbon cloths with said metal, said metal being selected from a group consisting of aluminum and titanium.

35. The method of claim 27 further comprising:

forming a plurality of porous separator sleeves using the porous separator material having been cut into strips prior to said interposing wherein said interposing step comprises fitting each of the plurality of porous separator sleeves over respective ones of one of said second plurality of electrodes.

36. The method of claim 35 wherein said forming said plurality of porous separator sleeves further comprises sealing edges of each of said plurality of porous separator sleeves.

37. The method of claim 27 wherein said interposing of said respective porous separator portion comprises fitting each of a plurality of porous separator sleeves comprising a separator material selected from a group of separator materials consisting of porous polypropylene and porous polyethylene, over one of said second plurality of electrodes.

39. The method of claim 33 wherein said applying comprises:

placing said wrapped interleaved metal-impregnated carbon electrode stack within a double-ended elongated container; and

attaching a terminal at each end of the double-ended elongated container, one or both of the terminals having a fill hole.

38. A method of packaging a double layer capacitor comprising:

placing a wrapped interleaved metal-impregnated carbon electrode stack within a container with electrode terminals the container having internal dimensions slightly smaller than a dimension of the metal-impregnated carbon electrode capacitor thereby applying a modest constant pressure against the metal-impregnated carbon electrode capacitor;

filling the container with an electrolytic solution; and

sealing the container;

wherein the modest constant pressure is less than 20 pounds per square inch.

40. The method of claim 38 wherein said applying comprises:

placing said wrapped interleaved metal-impregnated carbon electrode stack in between an upper conductive shell and a lower conductive shell; and

attaching the upper conductive shell and the lower conductive shell together, an interior dimension formed being smaller than a dimension of said wrapped interleaved electrode stack, thereby forcing said wrapped interleaved electrode stack to conform with the interior dimension.

41. A method of packaging a double layer capacitor comprising:

providing a wrapped interleaved electrode stack comprising a plurality of interleaved metal impregnated carbon cloth electrodes, each of the plurality of interleaved metal impregnated carbon cloth electrodes electrically being insulated from adjacent ones of the plurality of interleaved metal impregnated carbon cloth electrodes by a porous separator material, an insulating material surrounding the wrapped interleaved electrode stack;

applying a modest constant pressure against the interleaved electrode stack;

wherein the modest constant pressure is less than 20 pounds per square inch;

filling a capacitor container with an electrolytic solution, thereby saturating the wrapped interleaved electrode stack placed therein with the electrolytic solution, the electrolytic solution comprising a prescribed solvent into which a specified amount of a prescribed salt has been dissolved to form ions, the ions being able to readily pass through pores of the porous separator material; and

sealing the capacitor container, thereby maintaining the wrapped interleaved electrode stack immersed within the electrolytic solution.

42. The method of claim 41 wherein the modest constant pressure is between 5 pounds per square inch and 18 pounds per square inch.

43. The method of claim 41 wherein the modest constant pressure is about 10 pounds per square inch.

44. The method of claim 41 wherein the metal retained on the plurality of interleaved metal impregnated carbon cloth electrodes is between 42 and 53 percent of the total weight of the metal impregnated carbon cloth electrodes.

45. The method of claim 44 wherein the metal retained on the plurality of metal impregnated carbon cloths is about 48 percent of the total weight of the metal impregnated carbon cloths.

46. The method of claim 41 wherein the metal retained on the plurality of metal impregnated carbon cloth electrodes is about 15 percent of the total weight of the metal impregnated carbon cloth electrodes and the electrolytic solution.

47. The method in claim 41 wherein said metal-impregnated carbon electrode stack is placed within a conductive container.

48. The method in claim 41 further comprising insulating at least one electrode terminals from at least a portion of said container.