Dry particle based energy storage device product
View Patent ↗An inexpensive and reliable dry process based capacitor and method for making a self-supporting dry electrode film for use therein is disclosed. Also disclosed is an exemplary process for manufacturing an electrode for use in an energy storage device product, the process comprising: supplying dry carbon particles; supplying dry binder; dry mixing the dry carbon particles and dry binder; and dry fibrillizing the dry binder to create a matrix within which to support the dry carbon particles as dry material.
1. A method of manufacturing an electrode, comprising the steps of:
milling dry carbon and dry binder particles, wherein the dry binder particles consist essentially of fibrillizable binder particles and wherein the milling takes place in the absence of solvent and other binders to fibrillize said fibrillizable binder particles and to create a milled dry mixture;
compressing the milled dry mixture into a dry film; and
applying the dry film to a substrate to form an electrode.
2. The method of claim 1 wherein compressing the milled dry mixture comprises calendering the dry mixture to yield a self-supporting film.
3. The method of claim 1 wherein the dry film comprises between about 50% to 99% activated carbon.
4. The method of claim 1 wherein the dry film comprises between about 0% to 25% conductive carbon.
5. The method of claim 1 , wherein the dry film comprises between about 0.5% to 20% fibrillizable binder particles.
6. The method of claim 1 , wherein the dry film comprises between about 80% to 95% activated carbon and between about 0% to 15% conductive carbon, and about 3% to 15% dry binder.
7. The method of claim 1 wherein the milling is effected by a pin mill.
8. The method of claim 1 wherein the milling is effected by a jet mill.
9. The method of claim 1 wherein the milling is effected by a hammer mill.
10. The method of claim 1 wherein the milling is effected by impact pulverization.
11. The method of claim 1 wherein the dry film has a thickness in the range of 80 microns to 260 microns.
12. The method of claim 1 , wherein after the compressing step, the dry film formed from dry material comprises a density of greater than about 0.50 gm/cm 3 .
13. The method of claim 1 , wherein the dry film comprises a density of between about 0.50 and 0.70 gm/cm 3 .
14. The method of claim 1 wherein the binder comprises fibrillizable fluoropolymer.
15. The method of claim 14 wherein the fibrillizable fluoropolymer comprises polytetrafluoroethylene (PTFE).
16. The method of claim 1 wherein the dry film is applied on to the substrate by calendering.
17. The method of claim 16 wherein the dry film is calendered on to a substrate that had been treated by a method selected from the group consisting of etching or roughening.
18. The method of claim 1 wherein the substrate is selected from the group consisting of an aluminum sheet, foil, mesh, screen, or porous substrate.
19. An electrode for an energy storage device, comprising:
an electrically conductive substrate; and
a dry film comprising a milled dry mixture of carbon and dry binder, wherein the dry binder consists essentially of a fibrillizable binder, and wherein the dry film is free of processing solvent residue and free from additional binders, and wherein the dry film is bonded to the substrate.
20. The electrode of claim 19 , wherein the electrode is a capacitor electrode.
21. The electrode of claim 19 , wherein the electrode is a battery electrode.
22. The electrode of claim 19 , wherein the electrode is a fuel cell electrode.
23. The electrode of claim 19 , wherein the dry binder consists essentially of polytetrafluoroethylene (PTFE).
24. The electrode of claim 19 , wherein the dry binder consists of polytetrafluoroethylene (PTFE).
25. The electrode of claim 19 , wherein the substrate comprises an electrically conductive metal foil substrate.
26. The electrode of claim 19 , wherein the carbon comprises about 0 % to 15 % conductive carbon.
27. The electrode of claim 19 , wherein the carbon comprises graphite.