Ultracapacitor for use in a solder reflow process
An ultracapacitor that is capable of exhibiting good properties even after being subjected to high temperatures, such as experienced during solder reflow, is provided. The ultracapacitor contains a housing having sidewalls that extend in a direction generally perpendicular to a base. An interior cavity is defined between an inner surface of the base and the sidewalls within which an electrode assembly can be positioned. To attach the electrode assembly, first and second conductive members are disposed on the inner surface of the base. The electrode assembly likewise contains first and second leads that extend outwardly therefrom and are electrically connected to the first and second conductive members, respectively. The first and second conductive members are, in turn, electrically connected to first and second external terminations, respectively, which are provided on an outer surface of the base.
1. An ultracapacitor comprising:
a housing having sidewalls extending in a direction generally perpendicular to a base to define an upper end, wherein an interior cavity is defined between an inner surface of the base and the sidewalls, wherein the sidewalls and the base contain a ceramic material;
first and second conductive members disposed on the inner surface of the base;
first and second external terminations disposed on the outer surface of the base and electrically connected to the first and second conductive members, respectively;
a jellyroll electrode assembly positioned within the interior cavity and containing first and second leads extending outwardly therefrom, wherein the first and second leads are electrically connected to the first and second conductive members, respectively,
wherein the jellyroll electrode assembly contains a first electrode that comprises a first current collector electrically coupled to a first carbonaceous coating and a second electrode that comprises a second current collector electrically coupled to a second carbonaceous coating,
wherein the first carbonaceous coating, the second carbonaceous coating, or both contain activated carbon particles containing a plurality of pores,
wherein the amount of pores having a size of from about 2 nanometers to about 50 nanometers is about 20 vol. % to about 65 vol. % of the total pore volume and wherein the median pore width is 8 nanometers or less;
a nonaqueous electrolyte in ionic contact with the jellyroll electrode assembly; and
a lid disposed on the upper end of the sidewalls to seal the jellyroll electrode assembly and the electrolyte within the housing wherein a sealing member is disposed between the lid and the sidewalls.
2. The ultracapacitor of claim 1 , wherein the ceramic material comprises aluminum nitride, aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, glass, or a combination thereof.
3. The ultracapacitor of claim 1 , wherein each of the sidewalls and the base contains a polymeric material.
4. The ultracapacitor of claim 1 , wherein the first and second conductive members extend in a plane that is generally parallel to the base.
5. The ultracapacitor of claim 1 , wherein the first and second terminations extend in a plane that is generally parallel to the base.
6. The ultracapacitor of claim 1 , wherein the conductive members and terminations contain a metal.
7. The ultracapacitor of claim 1 , wherein the first and second leads extend from a front end of the jellyroll electrode assembly.
8. The ultracapacitor of claim 1 , wherein a major surface of the jellyroll electrode assembly is positioned parallel to the base.
9. The ultracapacitor of claim 1 , wherein a conductive trace is attached to the first conductive member and extends through the base and is attached to the first external termination, and further wherein a conductive trace is attached to the second conductive member and extends through the base and is attached to the second external termination.
10. The ultracapacitor of claim 1 , wherein the first current collector and the second current collector each contain a substrate that includes a conductive metal.
11. The ultracapacitor of claim 10 , wherein the conductive metal is aluminum or an alloy thereof.
12. The ultracapacitor of claim 10 , wherein a plurality of fiber-like whiskers project outwardly from the substrate of the first current collector, the substrate of the second current collector, or both.
13. The ultracapacitor of claim 12 , wherein the whiskers contain a carbide of the conductive metal.
14. The ultracapacitor of claim 10 , wherein the jellyroll electrode assembly further contains a separator positioned between the first electrode and the second electrode.
15. The ultracapacitor of claim 14 , wherein the first electrode, the second electrode, and the separator are folded into the jellyroll electrode assembly.
16. The ultracapacitor of claim 1 , wherein the first carbonaceous coating and the second carbonaceous coating contain activated carbon particles.
17. The ultracapacitor of claim 1 , wherein at least 50% by volume of the activated carbon particles have a size of from about 0.01 to about 30 micrometers.
18. The ultracapacitor of claim 1 , wherein the amount of pores having a size of about 2 nanometers or less is about 50 vol. % or less of the total pore volume and the amount of pores having a size of about 50 nanometers or more is from about 1 vol. % to about 50 vol. % of the total pore volume.
19. The ultracapacitor of claim 1 , wherein the nonaqueous electrolyte contains an ionic liquid that is dissolved in a nonaqueous solvent, wherein the ionic liquid contains a cationic species and a counterion.
20. The ultracapacitor of claim 19 , wherein the nonaqueous solvent includes propylene carbonate.
21. The ultracapacitor of claim 19 , wherein the cationic species includes an organoquaternary ammonium compound.
22. The ultracapacitor of clam 21 , wherein the organoquaternary ammonium compound has the following structure:
wherein m and n are independently a number from 3 to 7.
23. The ultracapacitor of claim 19 , wherein the ionic liquid is present at a concentration of about 1.0 M or more.
24. The ultracapacitor of claim 1 , wherein the first and second external terminations are electrically connected to the first and second conductive members, respectively, via a conductive adhesive.
25. The ultracapacitor of claim 24 , wherein the conductive adhesive includes a plurality of metal particles dispersed within a resinous material.
26. The ultracapacitor of claim 25 , wherein the resinous material is an epoxy resin.
27. A method for attaching the ultracapacitor of claim 1 to a circuit board, the method comprising placing the ultracapacitor and circuit board in contact with a solder paste and heating the solder paste to a peak temperature of about 150° C. or more.
28. The ultracapacitor of claim 1 , wherein the ultracapacitor exhibits a capacitance of about 6 Farads per cubic centimeter or more.
29. The ultracapacitor of claim 1 , wherein the first and second conductive members are electrically connected to the first and second external terminations, respectively, directly through the base.