SUPERCAPACITOR BASED ENERGY STORAGE DEVICE

1 . An energy storage device, comprising:

a charge storage component including an array of supercapacitors;

an auxiliary storage element; and

a charging control circuit configured to provide a charging current to the array of supercapacitors during a charging operation, wherein the charging control circuit is configured to selectively transfer charge between at least one supercapacitor in the array of supercapacitors and the auxiliary storage element,

wherein the charging control circuit includes a plurality of charging control circuits,

wherein each of the plurality of charging control circuits is coupled to one of the supercapacitors in the array of supercapacitors, and

wherein the charge storage component further includes a plurality of batteries, wherein each of the plurality of batteries is coupled to a corresponding supercapacitor in the array of supercapacitors.

2 . The energy storage device of claim 1 , further comprising an imbalance detection circuit,

wherein the charging control circuit is configured to transfer charge between the at least one supercapacitor and the auxiliary storage element when the imbalance detection circuit detects a charge imbalance between the at least one supercapacitor in the array and one or more remaining supercapacitors in the array.

3 . The energy storage device of claim 2 , wherein the imbalance detection circuit is configured to detect one of an overcharge imbalance or an undercharge imbalance, and

wherein the charge control circuit is configured to transfer charge from the at least one supercapacitor to the auxiliary storage element when an overcharge imbalance is detected, and

wherein the charge control circuit is configured to transfer charge from the auxiliary storage element to the at least one supercapacitor when an undercharge imbalance is detected.

4 . The energy storage device of claim 1 , wherein the charge control circuit comprises:

at least one pulse width modulation controller; and

a plurality of insulated gate bipolar transistors (IGBTs) electrically coupled to the at least one pulse width modulation controller, and

wherein the at least one pulse width modulation controller comprises a digital signal processor and at least one IGBT controller, the at least one IGBT controller being electrically coupled to the digital signal processor and configured to generate first control signals and second control signals for the plurality of IGBTs.

5 . The energy storage device of claim 1 , wherein each of the plurality of batteries comprises a lithium ion battery.

6 . The energy storage device of claim 1 , wherein the auxiliary storage element comprises a supercapacitor.

7 . The energy storage device of claim 1 , comprising a charge retention circuit configured to maintain a charge state of each supercapacitor in the array of supercapacitors when each supercapacitor is idle,

wherein the charge retention circuit is configured to generate a predetermined leakage current.

8 . The energy storage device of claim 1 , further comprising a control logic element coupled to the charge control circuit,

wherein the control logic element is configured to generate one or more control signals for the charge control circuit.

9 . The energy storage device of claim 1 , wherein the array of supercapacitors is coupled in series; and

further comprising: a charge retention circuit configured to maintain a charge state of each supercapacitor in the array of supercapacitors when each supercapacitor is in an idle state,

wherein the charge retention circuit comprises a plurality of charge retention circuits, and

wherein each of the plurality of charge retention circuits is coupled to a corresponding supercapacitor in the array of supercapacitors, and wherein the charge retention circuit is configured to generate a leakage current from a selected one of a plurality of batteries associated with an idle supercapacitor,

wherein the leakage current maintains the charge state of the idle supercapacitor.

10 . The energy storage device of claim 9 , wherein each of the plurality of batteries comprises a lithium-ion battery.

11 . The energy storage device of claim 1 , wherein the array of supercapacitors is coupled in series; and further comprising:

a plurality of charge retention circuits, wherein each of the plurality of charge retention circuits is coupled to a corresponding supercapacitor in the array of supercapacitors, and

wherein each of the plurality of charge retention circuits is configured to maintain a charge state of the corresponding supercapacitor in the array of supercapacitors when the corresponding supercapacitor is in an idle state.

12 . The energy storage device of claim 11 , further comprising an imbalance detection circuit, wherein the charge control circuit is configured to transfer charge between the at least one supercapacitor in the array and the auxiliary storage element when the imbalance detection circuit detects a charge imbalance between the at least one supercapacitor in the array and one or more remaining supercapacitors in the array.

13 . The energy storage device of claim 12 , wherein the imbalance detection circuit is configured to detect one of an overcharge imbalance or an undercharge imbalance,

wherein the charge control circuit comprises:

at least one pulse width modulation controller; and

a plurality of insulated gate bipolar transistors (IGBTs) electrically coupled to the at least one pulse width modulation controller, and

wherein the charge control circuit is configured to transfer charge from the at least one supercapacitor to the auxiliary storage element when an overcharge imbalance is detected, and wherein the charge control circuit is configured to transfer charge from the auxiliary storage element to the at least one supercapacitor when an undercharge imbalance is detected.