Battery-capacitor hybrid energy storage system for high temperature applications

1. A hybrid energy storage system (HESS) comprising:

a first energy storage device including a battery configured to provide a substantially constant power output; and

a second energy storage device linked to the first energy storage and including a high power electrochemical double layer capacitor (EDLC) for providing intermittent bursts of high power output over the range of 1.5 to 3.5 volts, wherein an operation rating of the second energy source is within a temperature range between 75 degrees Celsius and 330 degrees Celsius while exhibiting a leakage current less than 1 amp per liter of volume over the range of operating temperatures and at a voltage up to 3.5 volts;

wherein the HESS provides lower weight and volume than a battery energy storage system (BESS) that is capable of providing comparable bursts of high power output,

wherein the EDLC comprises two electrodes wetted with an electrolyte, each electrode being attached to or in contact with or coated onto a current collector and separated from each other by a separator porous to the electrolyte,

wherein the electrodes, electrolyte, and current collector contain less than 1,000 parts per million (ppm) of impurities, and

wherein the electrodes, electrolyte, and separator have a moisture concentration of less than 1,000 ppm.

2. The HESS of claim 1 wherein the battery is selected from the group consisting of lead-acid batteries, nickel cadmium batteries, nickel metal hydride batteries, lithium ion batteries, lithium polymer batteries, and combinations thereof.

3. The HESS of claim 1 , wherein each electrode comprises materials selected from the group consisting of carbon fibers, rayon, activated carbon, aerogel, graphene, carbon cloth, carbon nanotubes, or combinations thereof.

4. The HESS of claim 1 , wherein the separator comprises materials selected from the group consisting of non-woven glass, cellulosic material, polytetrafluoroethylene (PTFE), fiberglass, fluoropolymers, ceramics, or combinations thereof.

5. The HESS of claim 1 , wherein the electrolyte comprises a cation and an anion.

6. The HESS of claim 5 wherein the cation electrolyte is selected from the group consisting of 1-(3-Cyanopropyl)-3-methylimidazolium, 1,2-Dimethyl-3-propylimidazolium, 1,3-Bis(3-cyanopropyl)imidazolium, 1,3-Diethoxyimidazolium, 1-Butyl-1-methylpiperidinium, 1-Butyl-2,3-dimethylimidazolium, 1-Butyl-3-methylimidazolium, 1-Butyl-4-methylpyridinium, 1-Butylpyridinium, 1-Decyl-3-methylimidazolium, 1-Ethyl-3-methylimidazolium, 3-Methyl-1-propylpyridinium, and combinations thereof.

7. The HESS of claim 5 wherein the anion electrolyte is selected from the group consisting of bis(trifluoromethanesulfonate)imide, tris(trifluoromethanesulfonate)methide, dicyanamide, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, bis(pentafluoroethanesulfonate)imide, thiocyanate, trifluoro(trifluoromethyl)borate, and combinations thereof.

8. The HESS of claim 1 , wherein the electrolyte comprises a cation, an anion and a solvent.

9. The HESS of claim 8 wherein the solvent is Acetonitrile, Amides, Benzonitrile, Butyrolactone, Cyclic Ether, Dibutyl carbonate, Diethyl carbonate, Diethylether, Dimethoxyethane, Dimethyl carbonate, Dimethylformamide, Dimethylsulfone, Dioxane, Dioxolane, Ethyl formate, Ethylene carbonate, Ethylmethyl carbonate, Lactone, Linear Ether, Methyl formate, Methyl propionate, Methyltetrahydrofuran, Nitrile, Nitrobenzene, Nitromethane, N-methylpyrrolidone, Propylene carbonate, Sulfolane, Sulfone, Tetrahydrofuran, Tetramethylene sulfone, Thiophene, Ethylene glycol, Diethylene glycol, Triethylene glycol, Polyethylene glycols, Carbonic acid ester, γ-Butyrolactone, Nitrile, Tricyanohexane, or combinations thereof.

10. The HESS of claim 1 , wherein the impurities include halide ions (chloride, bromide, fluoride, iodide), free amines (ammonia), sulfate, metal cations (Ag, Al, Ba, Br, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sr, Ti, Zn), bromoethane, chloroethane, 1-bromobutane, 1-chlorobutane, 1-methylimidazole, ethyl acetate, methylene chloride, or combinations thereof.

11. The HESS of claim 1 , wherein the first energy storage device comprises lithium and the ELDC substantially free of lithium.

12. The HESS of claim 1 , wherein a moisture concentration of the electrolyte is less than 500 parts per million (ppm) over the weight or volume of the electrolyte.

13. The HESS of claim 1 , wherein each of the electrolyte, electrodes, separator, and current collector have been dried n an atmosphere with less than 50 parts per million (ppm) of water during assembly of the ELDC.

14. The HESS of claim 1 , wherein the electrolyte comprises an ionic liquid.

15. The HESS of claim 1 , wherein the EDLC is contained in a hermetically sealed housing.

16. A hybrid energy storage system (HESS) comprising:

a first energy storage device including a battery configured to provide a substantially constant power output; and

a second energy storage device linked to the first energy storage and including a high power electrochemical double layer capacitor (EDLC) for providing intermittent bursts of high power output over the range of 1.5 to 3.5 volts, wherein an operation rating of the second energy source is within a temperature range between 75 degrees Celsius and 330 degrees Celsius while exhibiting a leakage current less than 1 amp per liter of volume over the range of operating temperatures and at a voltage up to 3.5 volts;

wherein the first energy storage device is characterized by an energy density and capacity higher than that of the second energy storage device;

wherein the intermittent bursts of high power output by the second energy storage device are at a power higher than the constant power output of the first energy storage device;

wherein the EDLC comprises two electrodes wetted with an electrolyte, each electrode being attached to or in contact with or coated onto a current collector and separated from each other by a separator porous to the electrolyte,

wherein the electrodes, electrolyte, and current collector contain less than 1,000 parts per million (ppm) of impurities, and

wherein the electrodes, electrolyte, and separator have a moisture concentration of less than 1,000 ppm.