Power system for downhole toolstring

1. A downhole power system comprising:

a first rechargeable energy storage device (ESD) within a toolstring to provide power to one or more tools within the toolstring; and

a controller for controlling at least one of charging and discharging of the first ESD;

wherein the first ESD is configured to be operable at a temperature range of −40 degrees C. to 250 degrees C. to:

receive power from a power source at a first power level that is lower than a power requirement of a first tool in the toolstring, where the one or more tools in the toolstring comprises the first tool; and

output power to the one or more tools within the toolstring at a second power level that is at or above the requirement of the first tool in the toolstring; and

wherein the power system is coupled to a DC motor drive circuit, and a load of the DC motor drive circuit comprises a brushless DC motor; characterized in that the ESD comprises an ultracapacitor comprising an advanced electrolyte system (“AES”) and the AES comprises a salt of the following formula:

wherein R 1 is straight-chain or branched alkyl having 1 to 4 carbon atoms, R 2 is methyl or ethyl, and X − is [B(CN) 4 ]— or [BF n (CN) 4-n ]— where n=0, 1, 2 or 3;

wherein the AES is purified to contain less than 1000 ppm of chloride ions, less than about 100 ppm of fluoride ions, and/or less than about 100 ppm of water;

wherein the ultracapacitor comprises a positive electrode and a negative electrode, where at least one electrode comprises an energy storage media, the energy storage media comprising carbon nanotubes, the energy storage media consisting of at least 98% by mass elemental carbon; and

wherein at least one of the electrodes has a moisture content of less than 350 ppm and chloride content of less than 300 ppm.

2. The system of claim 1 , wherein the ESD receives power from the power source through a tool string power bus configured to provide power to one or more tools in the toolstring.

3. The system of claim 2 , wherein the first tool comprises at least one selected from the list consisting of: a nuclear magnetic resonance tool, a coring tool, a sonic tool, a neutron density tool, a gamma detector tool, a seismic measurement tool, a telemetry tool, a resistivity tool, and a formation tester.

4. The system of claim 2 , wherein the first ESD has an energy storage capacity in the range of 100 J to 100 kJ of energy.

5. The system of claim 4 , wherein the first ESD has an energy storage capacity of at least 1 kJ.

6. The system of claim 4 , wherein the first ESD is configured to provide an output voltage in the range of 30 V to 200 V.

7. The system of claim 4 , wherein the first ESD is configured to provide an output power in the range of 50 W to about 100 kW.

8. The system of claim 7 , wherein the first ESD has a peak output power of at least 100 W.

9. The system of claim 7 , wherein the first ESD has a peak output power of at least 1 kW.

10. The system of claim 7 , wherein the first ESD has an operational temperature range of −40 degrees C. to 210 degrees C.

11. The system of claim 7 , wherein the first ESD has an operational temperature range of −40 degrees C. to 200 degrees C.

12. The system of claim 7 , wherein the first ESD comprises a high temperature rechargeable energy storage device (HTRESD).

13. The system of claim 7 , wherein the HTRESD is an ultracapacitor.

14. The system of claim 13 , wherein the ultracapacitor has a volumetric power density of 50 kW/L to 120 kW/L.

15. The system of claim 13 , wherein the ultracapacitor has a volumetric power density of 100 kW/L to 120 kW/L.

16. The system of claim 15 , wherein the ultracapacitor is configured to operate at temperatures above 210 degrees Celsius for 10,000 charge/discharge cycles at a voltage of 0.5 V.

17. The system of claim 1 , wherein the first ESD is located adjacent to the first tool in the toolstring.

18. The system of claim 1 , wherein the power source comprises a downhole generator or downhole battery.

19. The system of claim 1 , further comprising:

a second ESD positioned within a toolstring to provide power to one or more instruments within the toolstring; where the one or more instruments within the toolstring comprises a second tool in the toolstring;

wherein the second ESD is configured to operate at temperatures at or above 210 degrees C. to:

receive power from a power source at a first power level that is lower than a power requirement of the second tool in the toolstring, and

output power to the tool at a second power level that is at or above the requirement of the second tool in the toolstring.

20. The system of claim 1 , further comprising:

a modular signal interface device (“MSID”) module for controlling at least one of the power provided to a downhole tool connected to the downhole power system and the charge-discharge cycles of the first ESD, wherein the MSID is adapted to connect to the power source.