Capacitor with a double electric layer

• US 5,557,497 A
• Filed: 07/02/1993
• Issued: 09/17/1996
• Est. Priority Date: 07/03/1992
• Status: Expired due to Term

• Current Assignee: Econd International, Inc.
• Original Assignee: ECOND
• Inventors: Fomin, Andrei V., Efimov, Sergei E., Savintsev, Vadim G., Gerasimov, Arkadiy F., Ivanov, Alexander M., Bognitski, Isaac Y., Chizhevski, Sergei V.
• Primary Examiner(s): Walberg, Teresa J.
• Assistant Examiner(s): Mills, Gregory L.
• Application Number:
  US08/086,910
• Time in Patent Office: 1,173 Days
• Field of Search: 361/502, 361/505, 29/25.03, 252/502, 252/510, 252/511, 429/210, 429/212, 429/213, 429/217, 264/105
• US Class Current: 361/502
• CPC Class Codes: H01G 11/24 characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
• CPC Class Codes: H01G 11/30 characterised by their material
• CPC Class Codes: H01G 11/32 Carbon-based
• CPC Class Codes: H01G 11/48 Conductive polymers
• CPC Class Codes: H01G 9/042 characterised by the material H01G11/22 takes precedence
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

This invention relates to a large capacitor for accumulating electrical energy. In particular, to a capacitor with a double electric layer comprising an electrolyte; at least one pair of electrolyte impregnated electrodes which are elastically compressible and independently, mechanically stable; and a separator also impregnated with electrolyte for being in between and in contact with both of the at least one pair of electrolytic impregnated electrodes for ionic conductance but electronically separating the electrodes; at least one pair of electrolytes impermeable and electrolyte inert current collectors in contact respectively with the at least one pair of the electrolyte impregnated electrodes; and an insulating gasket for separating the electrolyte impermeable and electrolytic inert collectors.

In at least some embodiments of this capacitor, the electrolytic impregnated electrodes are composed of various forms of carbon particles in combination with porous elastic dielectrics and polymer binders.

Claims

1. An electrical capacitor comprising

a. an electrolyte,

b. at least one pair of electrolyte-impregnated electrodes which are elastically compressible and independently mechanically stable, said electrodes comprising a porous elastic dielectric means and a separate polymer binder,

c. a separator impregnated with said electrolyte between and in contact with both of said at least one pair of electrolyte-impregnated electrodes for ionic conductance and electronically separating said electrodes,

d. at least one pair of electrolyte-impermeable and electrolyte inert current collectors having a first and a second of said pair in contact with a first and a second respectively of the at least one pair of electrolyte-impregnated electrodes, and

e. an uncompressed gasket for separating said at least one pair of electrolyte-impermeable and electrolyte inert current collectors outward of said separator and along the capacitor perimeter.

2. An electrical capacitor of claim 1 wherein said one pair of electrolyte-impregnated electrodes which are elastically compressible and independently mechanically stable are further comprised of

a. coarse porous particles,

b. relatively smaller particles down to one-thousandth of the size of said coarse particles, and

c. three-dimensional elastic matrix means formed by the polymer binder and having ramified spaces for positioning said porous elastic dielectric means, said coarse porous particles and said relatively smaller particles therein so as to be in contact with each other and for said electrolyte used to impregnate said electrodes for forming a three-dimensional electron-conducting ramified mass, said relatively smaller particles being positioned in the interstices between said course porous particles in said matrix for enhanced surface-to-surface particle contact.

3. An electrical capacitor of claim 2 wherein said coarse porous particles comprise a mixture of activated carbon particles, and said relatively smaller particles comprise dispersed carbon.

4. An electrical capacitor of claim 5 wherein said mixture of activated carbon particles comprises a mixture of coarse porous particles having an average size within the range of 1-100 microns and said mixture of small particles comprises a mixture of relatively smaller particles having an average size within the range of 0.1 to 1 micron and the content of said small particles being within the range of 1.0 to 30% percent by weight.

5. An electrical capacitor of claim 3 wherein said mixture of activated carbon particles comprises a mixture of coarse porous particles having an average size within the range of 1-100 microns and said relatively smaller dispersed carbon particles have an average size within the range of 0.1 to 1 micron and the content of said smaller dispersed carbon particles being within the range of 1.0% to 40% percent by weight.

6. An electrical capacitor of claim 5 wherein said smaller dispersed carbon particles are carbon black.

7. An electrical capacitor of claim 5 wherein said smaller dispersed carbon particles are graphite carbon.

8. An electrical capacitor of claim 2 wherein the content of said porous elastic dielectric means in said at least one pair of electrolyte-impregnated electrodes is within the range of 1% to 30% by weight.

9. An electrical capacitor of claim 8 wherein said porous elastic dielectric means further comprises a cellular plastic material having communicating pores and an average diameter size of said material is within the range of 1 to 50 microns.

10. An electrical capacitor of claim 9 wherein said cellular plastic material is micro-porous rubber.

11. An electrical capacitor of claim 2 wherein said porous elastic dielectric mean further comprises fibrous dielectric materials having a diameter of fibers from 0.3 to 50 microns, and lengths thereof from 0.1 to 5 millimeters.

12. An electrical capacitor of claim 2 wherein said polymer binder further comprises a polyvinyl alcohol.

13. An electrical capacitor of claim 2 wherein said polymer binder further comprises a polysaccharide.

14. An electrical capacitor of claim 2 wherein said polymer binder further comprises rubber.

15. An electrical capacitor of claim 2 wherein said polymer binder further comprises a fluoroplastic.

16. An electrical capacitor of claim 2 wherein said separator and said at least one pair of electrolyte impermeable and electrolyte inert current collectors are made from surface conforming pliable materials for substantial contact with said at least one pair of electrolyte-impregnated electrodes when said capacitor is compressed.

17. An electrical capacitor of claim 16 wherein said at least one pair of electrolyte impermeable and electrolyte inert current collectors are made of foil.

18. An electrical capacitor of claim 2 wherein said gasket separating said at least one pair of electrolyte impermeable and electrolyte inert current collectors is sufficiently thin so as to be substantially below the external surfaces of said at least one pair of electrolyte impermeable and electrolyte inert current collectors for allowing compressive deformation of said capacitor and no compression on said gasket.

19. An electrical capacitor of claim 1 wherein said porous elastic dielectric means comprises fibrous dielectric materials.

20. An electrical capacitor of claim 1 wherein said one pair of electrolyte-impregnated electrodes which are elastically compressible and independently mechanically stable are further comprised of

a. large porous particles,

b. relatively smaller porous particles down to one-thousandth of the size of said coarse particles, and

c. three-dimensional elastic matrix means formed by the polymer binder and having ramified spaces for positioning said porous elastic dielectric means, said large porous particles and said relatively smaller porous particles therein so as to be in contact with each other and for said electrolyte used to impregnate said electrodes for forming a three-dimensional electron-conducting ramified mass, said relatively smaller particles being positioned in the interstices between said large porous particles in said matrix for enhanced surface-to-surface particle contact.

21. An electrical capacitor of claim 20 wherein said porous elastic dielectric means further comprises fibrous dielectric materials.

22. An electrical capacitor of claim 21 wherein said large porous particles further comprises a mixture of activated carbon particles, and said relatively smaller porous particles further comprises smaller activated carbon particles than said large porous particles.

23. An electrical capacitor of claim 22 wherein said mixture of activated carbon particles further comprises a mixture of large porous particles having an average diameter size within the range of 5 to 50 and said smaller porous carbon particles further comprises a mixture of small particles having an average diameter size within the range of 0.5 to 5 microns and the content of said small particles being within the range of 10% to 50% by weight of said large porous particles.

24. An electrical capacitor of claim 22 wherein said porous elastic dielectric means further comprises porous elastic dielectric particles having an average diameter size within the range of 1 to 50 microns and said porous elastic dielectric particles being within the range of 1.0% to 30% by weight of said large porous particles.

25. An electrical capacitor of claim 24 wherein said porous elastic dielectric further comprises a porous-plast having communicating pores.

26. An electrical capacitor of claim 25 wherein said porous-plast material is micro-porous rubber.

27. An electrical capacitor of claim 22 wherein said polymer binder further comprises a polyvinyl alcohol.

28. An electrical capacitor of claim 22 wherein said polymer binder further comprises a polysaccharide.

29. An electrical capacitor of claim 22 wherein said polymer binder further comprises rubber.

30. An electrical capacitor of claim 22 wherein said separator and said at least one pair of electrolyte impermeable and electrolyte inert current collectors are made from surface conforming pliable materials for substantial contact with said at least one pair of electrolyte-impregnated electrodes when said capacitor is compressed.

31. An electrical capacitor of claim 22 wherein said at least one pair of electrolyte impermeable and electrolyte inert current collectors are made of foil.

32. An electrical capacitor of claim 22 wherein said gasket separating said at least one pair of electrolyte impermeable and electrolyte inert current collectors is sufficiently thin so as to be substantially below the external surfaces of said at least one pair of electrolyte impermeable and electrolyte inert current collectors for allowing compressive deformation of said capacitor and no compression on said gasket.

33. An electric double layer capacitor comprising

a. at least one pair of electrodes made of a mixture of activated carbon, dispersed carbon, porous dielectric particles and separate polymer binder means,

b. separator means separating and in contact with at least one pair of said electrodes for ionic conductance and electronically separating said electrodes,

c. a liquid electrolyte impregnating at least one pair of said electrodes and said separator,

d. at least a pair of electrolyte impermeable and electrolyte inert current collectors in contact with at least one pair of said electrolyte impregnated electrodes, forming the body of the electric double layer capacitor, and

e. an insulating gasket means along the perimeter and in between said current collectors separating said current collectors and at the same time preventing the leakage of said electrolyte from the capacitor.

34. A capacitor of claim 33, wherein said mixture comprises activated carbon particles having an average diameter within the range of 1 to 100 microns and small particles of dispersed carbon having an average diameter within the range of 0.1 to 1 microns, the content of said small particles being within the range of 1.0 to 40 percent by weight.

35. A capacitor of claim 34, wherein said mixture comprises dispersed carbon within the range of 1.0 to 30 percent by weight.

36. A capacitor of claim 34, wherein said mixture comprises porous-plast particles within the range of 1 to 30 percent by weight.

37. A capacitor of claim 36, wherein said porous-plast particles have an average diameter in the range of 1 to 50 microns.

38. A capacitor of claim 36, wherein said mixture comprises fibrous porous plast particles, the fibers having an average diameter of 0.3 to 50 microns and a length of 0.1 to 5 millimeters.

39. A capacitor of claim 33, wherein said mixture comprises coarse activated carbon particles having an average diameter within the range of 5 to 50 microns and small particles having an average diameter within the range of 0.5 to 5 microns, the content of said small particles being within the range of 10 to 50 percent by weight.

40. A capacitor of claim 39, wherein said mixture comprises porous-plast particles within the range of 1 to 30 percent by weight.

41. A capacitor of claim 40, wherein said porous-plast particles have an average diameter in the range of 1 to 50 microns.

42. A capacitor of claim 40, wherein said mixture comprises fibrous porous plast particles, the afibers having an average diameter of 0.3 to 50 microns and a length of 0.1 to 5 millimeters.