Non-linear capacitor and energy storage device comprising thereof

Abstract

The present disclosure provides a non-linear capacitor comprising a first electrode, a second electrode, and a dielectric layer disposed between said first and second electrodes. The dielectric layer comprises at least one organic compound selected from copolymer, homo-polymer, Sharp polymers, NLSD compounds and combination thereof which have at least one electro-polarizable aromatic polycyclic conjugated core. A relationship between a capacity C of the capacitor and a voltage V between the electrodes is characterized by the monotonously increasing polynomial dependence C.sub.0+.sub.i=1.sup.m C.sub.iV.sup.i, when the voltage V satisfies by following inequality 0<VV.sub.max, where the voltage V.sub.max is a maximum working voltage that does not exceed a breakdown voltage V.sub.bd and which is selected out of safety reasons, where at least one coefficient C.sub.i is not equal to 0 when the index i ranges from 2 to m, and m=2, 3, 4, 5, or 6.

Claims

1. A non-linear capacitor comprising a first electrode, a second electrode, and a dielectric layer disposed between said first and second electrodes, wherein the dielectric layer comprises at least one organic compound selected from copolymer, homo-polymer, Sharp polymers, NLSD compounds and combination thereof which have at least one electro-polarizable aromatic polycyclic conjugated core, wherein a relationship between a capacity C of the capacitor and a voltage V between the first and second electrodes is characterized by a monotonically increasing polynomial dependence C.sub.0+.sub.i=1.sup.m C.sub.iV.sup.i, when the voltage V satisfies by following inequality 0<VV.sub.max, where the voltage V.sub.max is the maximum working voltage that does not exceed breakdown voltage V.sub.bd and which is selected out of safety reasons, where at least one coefficient C.sub.i is not equal to 0 when the index i ranges from 2 to m, and m=2, 3, 4, 5, or 6.

2. The non-linear capacitor according to claim 1, wherein a working range of voltage is from V.sub.int to V.sub.max where V.sub.int is determined by the intersection the straight line that is tangent to the dependence Q(V)=C(V).Math.V at the point V=V.sub.max with the abscissa axis, and the difference between voltages V.sub.max and V.sub.int is defined by the following ratio: $V_{\mathrm{ma}x}-V_{int}=\frac{Q\left(V_{\mathrm{ma}x}\right)}{\frac{\mathrm{dQ}}{\mathrm{dV}}{|}_{V_{\mathrm{ma}x}}}$ .

3. The non-linear capacitor according to claim 1, wherein the electro-polarizable aromatic polycyclic conjugated cores interact with each other due to dipole and - interactions and form molecular stacks, and the organic compound further comprises alkyl tail-substituents which are bonded to the polymer backbone or to conjugated Sharp and NLSD molecular compounds, wherein the alkyl tail-substitutes interact with each other due to hydrophobic interaction and also form isolating cover round the molecular stacks, provide solubility of the organic compound, and preclude an avalanche breakdown of the dielectric layer at the working voltage applied to the electrodes of the capacitor.

4. The non-linear capacitor according to claim 1, wherein the electro-polarizable aromatic polycyclic conjugated core comprises benzene rings bonded with linker groups and is described by following structure formula: ##STR00037## where L is linker group which is selected from NN, CC (alkyl/and CHCH and n=0, 1, 2, 3, 4, 5, and 6.

5. The non-linear capacitor according to claim 1, wherein the electro-polarizable aromatic polycyclic conjugated core further comprises electrophilic groups (acceptors) and/or nucleophilic groups (donors) located in apex positions and/or in side (lateral) positions.

6. The non-linear capacitor according to claim 5, wherein the electrophilic groups (acceptors) are selected from NO.sub.2, NH.sub.3.sup.+ and NRRR (quaternary nitrogen salts), counterion Cl.sup. or Br.sup., CHO (aldehyde), CRO (keto group), SO.sub.3H (sulfonic acids), SO.sub.3R (sulfonates), SO.sub.2NH.sub.2 (sulfonamides), COOH (carboxylic acid), COOR (esters, from carboxylic acid side), COCl (carboxylic acid chlorides), CONH2 (amides, from carboxylic acid side), CF.sub.3, CCl.sub.3, CN, wherein R is radical selected from the list comprising alkyl (methyl, ethyl, isopropyl, tert-butyl, neopentyl, cyclohexyl etc.), allyl (CH2-CHCH2), benzyl (CH2C6H5) groups, phenyl (+substituted phenyl) and other aryl (aromatic) groups and where R & R are independently selected for list of R radicals.

7. The non-linear capacitor according to claim 5, wherein the nucleophilic groups (donors) are selected from O.sup. (phenoxides, like ONa or OK), NH.sub.2, NHR, NR.sub.2, OH, OR (ethers), NHCOR (amides, from amine side), OCOR (esters, from alcohol side), alkyls, C.sub.6H.sub.5, vinyls, NRR wherein R and R are radicals independently selected from the list comprising alkyl (methyl, ethyl, isopropyl, tert-butyl, neopentyl, cyclohexyl etc.), allyl (CH2-CHCH2), benzyl (CH2C6H5) groups, phenyl (+substituted phenyl) and other aryl (aromatic) groups.

8. The non-linear capacitor according to claim 3, wherein at least one tail-substituent is independently selected from the list comprising (CH.sub.2).sub.nCH.sub.3, CH((CH.sub.2).sub.nCH.sub.3).sub.2) (where n1), alkyl, aryl, substituted alkyl, substituted aryl, branched alkyl, branched aryl, complex cyclic alkyl groups, X=CH(CH2)nCH3, CC(CH2)nCH3, X=C((CH2)nCH3)((CH2)mCH3) and any combination thereof and wherein the alkyl group is selected from methyl, ethyl, propyl, butyl, i-butyl and t-butyl groups, and the aryl group is selected from phenyl, benzyl and naphthyl groups where X is C, S, or N and n and m are independently selected from 1-20.

9. The non-linear capacitor according to claim 1, wherein the copolymers are selected from YanLi materials having following structures 1 to 26: TABLE-US-00003 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26.

10. The non-linear capacitor according to claim 2, wherein the voltage V.sub.int aspires to the maximum voltage V.sub.max when the derivative $\frac{\mathrm{dQ}}{\mathrm{dV}}{|}_{V_{\mathrm{ma}x}}$ is increased.

11. The non-linear capacitor according to claim 2, wherein the ratio (V.sub.maxV.sub.int)/V.sub.max is less than 0.1.

12. The non-linear capacitor according to claim 2, wherein the voltage V applied to the electrodes is approximately constant and is changed in a range between the voltage V.sub.int and the voltage V.sub.max during charging/discharging of the capacitor until (while) the charge Q on the electrodes is changed in a range between the charge Q.sub.int=Q(V.sub.int) and the maximum charge Q.sub.max=Q(V.sub.max).

13. The non-linear capacitor according to claim 1, wherein the organic compound is characterized by an induced polarisation P.sub.ind approximated by a decomposition into a series on degrees of intensity of a local electric field E.sub.loc: $P_{i\mathrm{nd}}=.Math.E_{\mathrm{loc}}+.Math.E_{\mathrm{loc}}^2+\mathrm{.Math.},$ where is a linear polarizability, is a square polarizability.

14. An energy storage device comprising the non-linear capacitor with a power-law dependence of capacitance on voltage according to claim 1, which uses a power electronics in a voltage range from V.sub.max 200 volts to V.sub.max 1000 volts.

15. An energy storage device comprising the non-linear capacitor with a power-law dependence of capacitance on voltage according to claim 1, which uses a power electronics and operates at a V.sub.max voltage greater than 1000 volts.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) A more complete assessment of the present invention and its advantages will be readily achieved as the same becomes better understood by reference to the following detailed description, considered in connection with the accompanying drawings and detailed specification, all of which forms a part of the disclosure. Embodiments of the invention are illustrated, by way of example only, in the following Figures, of which:

(2) FIG. 1 schematically shows a relation between a charge Q on the electrodes of the capacitor and a voltage V applied to the electrodes.

(3) FIG. 2A schematically shows the disclosed capacitor with flat and planar electrodes.

(4) FIG. 2B schematically shows the disclosed capacitor with rolled (circular) electrodes.

(5) FIG. 3 schematically shows how the charge Q on the electrodes of a capacitor depends on the voltage applied to the electrodes of the nonlinear capacitor (F) and linear capacitor (D).

(6) FIG. 4 schematically shows an energy storage cell utilizing an energy storage device according to aspects of the present disclosure.

(7) FIG. 5 shows an example of a capacitive energy storage module having two or more networked energy storage cells according to an alternative aspect of the present disclosure.

(8) FIG. 6 shows an example of a capacitive energy storage system having two or more energy storage networked modules according to an alternative aspect of the present disclosure.

DETAILED DESCRIPTION

(9) While various embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.

(10) The present disclosure provides the non-linear capacitor as disclosed above. In one embodiment of the non-linear capacitor, the working range of voltage is from V.sub.int to V.sub.max where V.sub.int is determined by the intersection the straight line that is tangent to the dependence Q(V)=C(V).Math.V at the point V=V.sub.max with the abscissa axis, and the difference between voltages V.sub.max and V.sub.int is defined by the following ratio:

(11) $V_{\mathrm{ma}x}-V_{int}=\frac{Q\left(V_{\mathrm{ma}x}\right)}{\frac{\mathrm{dQ}}{\mathrm{dV}}{|}_{V_{\mathrm{ma}x}}}$

(12) In another embodiment of the present disclosure, the electro-polarizable aromatic polycyclic conjugated cores interact with each other due to dipole and - interactions and form molecular stacks, and the organic compound further comprises alkyl tail-substituents which are bonded to the polymer backbone or to conjugated Sharp and NLSD molecular compounds. The alkyl tail-substitutes interact with each other due to hydrophobic interaction and also form isolating cover round the molecular stacks, provide solubility of the organic compound, and preclude an avalanche breakdown of the dielectric layer at the working voltage applied to the electrodes of the capacitor. In yet another embodiment of the present disclosure, the electro-polarizable aromatic polycyclic conjugated core comprises benzene rings bonded with linker groups and is described by following structure formula:

(13) ##STR00001##
where L is linker group which is selected from NN, CC (alkyne) and CHCH and n=0, 1, 2, 3, 4, 5, and 6. In still another embodiment of the present disclosure, the electro-polarizable aromatic polycyclic conjugated core further comprises electrophilic groups (acceptors) and/or nucleophilic groups (donors) located in apex positions and/or in side (lateral) positions. The electrophilic groups (acceptors) are selected from NO.sub.2, NH.sub.3.sup.+ and NRRR (quaternary nitrogen salts), counterion Cl.sup. or Br.sup., CHO (aldehyde), CRO (keto group), SO.sub.3H (sulfonic acids), SO.sub.3R (sulfonates), SO.sub.2NH.sub.2 (sulfonamides), COOH (carboxylic acid), COOR (esters, from carboxylic acid side), COCl (carboxylic acid chlorides), CONH2 (amides, from carboxylic acid side), CF.sub.3, CCl.sub.3, CN, wherein R is radical selected from the list comprising alkyl (methyl, ethyl, isopropyl, tert-butyl, neopentyl, cyclohexyl etc.), allyl (CH2-CHCH2), benzyl (CH2C6H5) groups, phenyl (+substituted phenyl) and other aryl (aromatic) groups and where R R are independently selected for list of R radicals. The nucleophilic groups (donors) are selected from O.sup. (phenoxides, such as ONa or OK), NH.sub.2, NHR, NR.sub.2, OH, OR (ethers), NHCOR (amides, from amine side), OCOR (esters, from alcohol side), alkyls, C.sub.6H.sub.5, vinyls, NRR wherein R and R are radicals independently selected from the list comprising alkyl (methyl, ethyl, isopropyl, tert-butyl, neopentyl, cyclohexyl etc.), allyl (CH2-CHCH2), benzyl (CH2C6H5) groups, phenyl (+substituted phenyl) and other aryl (aromatic) groups.

(14) Existence of the electrophilic groups (acceptors) and the nucleophilic groups (donors) in the aromatic polycyclic conjugated molecule promotes non-uniform distribution of electronic density in the conjugated molecule: surplus of electrons in one place (in a donor zone) and a shortage of electrons in other place (in an acceptor zone). The influence of an external electric field on a non-uniform distribution of electronic density along the conjugated molecule leads to an induced polarization P.sub.ind. In the general case the induced polarization is a nonlinear function of intensity of the local electric field E.sub.loc. In the assumption of weak nonlinearity it is possible to approximate the induced polarization P.sub.ind by a few terms of a decomposition of the induced polarization into a series of degrees of intensity of a local electric field. In such situations the induced polarization of the environment (e.g., of a molecule) can be written down in the following form:

(15) $P_{i\mathrm{nd}}=.Math.E_{\mathrm{loc}}+.Math.E_{\mathrm{loc}}^2+\mathrm{.Math.},$
where -linear polarizability, -square polarizability. Though the assumption of a smallness of electric field is not always right, nevertheless parameters and may be used for qualitative analysis of polarizability of the disclosed compounds. In the present disclosure the main attention is paid to ways of increase in the induced polarization of the disclosed compounds and therefore onto ways of increase of the linear polarizability and square polarizability . Such attention is caused by that the constant dipole and quadrupole electrical moments are mutually neutralized at self-assembly of such conjugated molecules. The analysis shows that linear polarizability depends on the size of average electronic density in the molecule, and nonlinear polarizability depends on the size of heterogeneity of electronic density. It is also shown that a non-centrosymmetric arrangement of the electron donor and acceptor groups can lead to a strong nonlinear response of the compound's electronic polarization in the presence of an electric field. Influence of chemical structure on linear polarizability and square polarizability is shown in Table 1.

(16) TABLE-US-00001 TABLE 1 Examples of the chemical structure with linear polarizability and square polarizability chemical structure 945 0.041 1348 0.165 1537 862 1252 21107 1908 40221 1431 35189 2057 168081 3397 582843 0 4604 1002570
Table 1 indicates the placement and of electron donating and electron withdrawing groups on an electron conjugated system is important to increasing polarizability. Further, Table 1 structures are indicative of conjugated ring systems that may be further modified to enhance polarizability. However, they are non-limiting examples, and require additional resistive substituents (tails) to achieve high resistivity.

(17) In another embodiment of the present disclosure, at least one tail-substituent is independently selected from the list comprising (CH.sub.2).sub.nCH.sub.3, CH((CH.sub.2).sub.nCH.sub.3).sub.2) (where n1), alkyl, aryl, substituted alkyl, substituted aryl, branched alkyl, branched aryl, complex cyclic alkyl groups, X=CH(CH2)nCH3, CC(CH2)nCH3, XC((CH2)nCH3)((CH2)mCH3) and any combination thereof and wherein the alkyl group is selected from methyl, ethyl, propyl, butyl, i-butyl and t-butyl groups, and the aryl group is selected from phenyl, benzyl and naphthyl groups where X is C, S, or N and n and m are independently selected from 1-20. In yet another embodiment of the present disclosure, the copolymers are selected from YanLi materials having following structures 1 to 26 as shown in Table 2 below.

(18) TABLE-US-00002 TABLE 2 Examples of the Yan Li materials 1 2 3 4 5 6 7 8 9 0 10 11 12 13 14 15 16 17 18 19 0 20 21 22 23 24 25 26

(19) In one embodiment of the disclosed non-linear capacitor, the voltage V.sub.int aspires to the maximum voltage V.sub.max when the derivative

(20) $\frac{\mathrm{dQ}}{\mathrm{dV}}{|}_{V_{\mathrm{ma}x}}$
is increased. In another embodiment of the disclosed non-linear capacitor, the ratio (V.sub.maxV.sub.int)/V.sub.max is less than 0.1. In yet another embodiment of the disclosed non-linear capacitor, the voltage V applied to the electrodes is approximately constant and is changed in a range between the voltage V.sub.int and the voltage V.sub.max during charging/discharging of the non-linear capacitor until (while) the charge Q on the electrodes is changed in a range between the charge Q.sub.int=Q(V.sub.int) and the maximum charge Q.sub.max=Q(V.sub.max). In another embodiment of the disclosed non-linear capacitor, the organic compound is characterized by an induced polarization P.sub.ind which may be written down in the form of decomposition into a series on degrees of intensity of a local electric field E.sub.loc:

(21) $P_{i\mathrm{nd}}=.Math.E_{\mathrm{loc}}+.Math.E_{\mathrm{loc}}^2+\mathrm{.Math.},$
where -linear polarizability, -square polarizability.

(22) The present disclosure provides the energy storage device as disclosed above.

(23) In order that the invention may be more readily understood, reference is made to the following Figures, which are intended to be illustrative of the present disclosure, but is not intended to be limiting in scope.

(24) FIG. 1 schematically shows a relation between a charge Q=C(V).Math.V on the electrodes of the capacitor and a voltage V applied to the electrodes (see, a curve A). The charge Q is non-linearly dependent on the voltage V according to the following monotonously increasing polynomial dependence Q (V)=(C.sub.0+.sub.i=1.sup.m C.sub.iV.sup.i).Math.V, when the voltage V satisfies following inequality 0<VV.sub.max, where the voltage V.sub.max is the maximum working voltage that does not exceed breakdown voltage V.sub.bd and which is selected out of security reasons, the coefficients Q.sub.i characterize the nonlinearity of the charge Q of the i-th order, m=1, 2, 3, 4, 5, or 6, and Q.sub.11=Q (V.sub.max). The straight line 2 is a tangent to the nonlinear dependence Q (V) when the voltage V is equal to the maximum voltage, i. e. V=V.sub.max. This straight line B crosses the abscissa at the point V=V.sub.int and the charge corresponding to this voltage is equal to Q.sub.int=Q (V.sub.int). The following ratio is carried out for the difference between two voltages V.sub.max and V.sub.int:

(25) $V_{\mathrm{ma}x}-V_{int}=\frac{Q\left(V_{\mathrm{ma}x}\right)}{\frac{\mathrm{dQ}}{\mathrm{dV}}{|}_{V_{\mathrm{ma}x}}}.$

(26) It follows from the above expression that the difference V.sub.maxV.sub.int is decreased with increasing of steepness of the nonlinear dependence at the maximum voltage V.sub.max. During charging/discharging of the capacitor the voltage V changes in an interval between V.sub.max and V.sub.int while the charge Q changes between Q.sub.max and Q.sub.int.

(27) The present disclosure provides the non-linear capacitor comprising two metal electrodes positioned parallel to each other and which can be rolled or flat and planar and dielectric layer between this electrodes. The dielectric layer comprises at least one organic compound selected from copolymer, homo-polymer, Sharp polymers, NLSD compounds and combination thereof which have at least one electro-polarizable aromatic polycyclic conjugated core as disclosed above.

(28) The non-linear capacitor comprises a first electrode 1, a second electrode 2, and a dielectric layer 3 disposed between said first and second electrodes as shown in FIG. 2A. The electrodes 1 and 2 may be made of a metal, such as copper, zinc, or aluminum or other conductive material and are generally planar in shape.

(29) The electrodes 1, 2 may be flat and planar and positioned parallel to each other. Alternatively, the electrodes may be planar and parallel, but not necessarily flat, they may be coiled, rolled, bent, folded, or otherwise shaped to reduce the overall form factor of the capacitor. It is also possible for the electrodes to be non-flat, non-planar, or non-parallel or some combination of two or more of these. By way of example and not by way of limitation, a spacing d between the electrodes 1, 2 may range from about 100 nm to about 10 000 m. The maximum voltage V.sub.bd between the electrodes 1, 2 is approximately the product of the breakdown field E.sub.bd and the electrode spacing d. If E.sub.bd=0.1 V/nm and the spacing d between the electrodes 1 and 2 is 10,000 microns (100,000 nm), the maximum voltage V.sub.bd would be 100,000 volts.

(30) The electrodes 1, 2 may have the same shape as each other, the same dimensions, and the same area A. By way of example, and not by way of limitation, the area A of each electrode 1, 2 may range from about 0.01 m.sup.2 to about 1000 m.sup.2. These ranges are non-limiting. Other ranges of the electrode spacing d and area A are within the scope of the aspects of the present disclosure.

(31) The present disclosure include non-linear capacitors that are coiled, e.g., as depicted in FIG. 2B. In this example, a capacitor 20 comprises a first electrode 21, a second electrode 22, and a dielectric material layer 23 of the type described hereinabove disposed between said first and second electrodes. The electrodes 21, 22 may be made of a metal, such as copper, zinc, or aluminum or other conductive material and are generally planar in shape. In one implementation, the electrodes and dielectric material layer 23 are in the form of long strips of material that are sandwiched together and wound into a coil along with an insulating material, e.g., a plastic film such as polypropylene or polyester to prevent electrical shorting between the electrodes 21, 22.

(32) FIG. 3 schematically illustrates dependence of the charge (Q) accumulated on electrodes on the voltage (V) enclosed to the device (Q-V plot) for a standard material (D) and a material of the dielectric layer having at least one organic compound selected from copolymer, homo-polymer, Sharp polymers, NLSD compounds and combination thereof which have at least one electro-polarizable aromatic polycyclic conjugated core (F).

(33) With reference to FIG. 3, the total energy stored in an exemplary device can depend on, for example, (a) the maximum attainable voltage across the device electrodes, V.sub.max, (b) the charge stored on the device electrodes at this voltage, Q.sub.max and/or (c) the form of the Q-V curve for the device. Generally, the energy total stored in the device, E, is given by Equation (I):
E=.sub.0.sup.QmaxV(Q)dQ(I)

(34) Without limitation, the energy stored in devices (and energy density) may be increased in at least the following three ways: increase of the breakdown voltage, increase of permittivity c of dielectric material of the metadielectric layer, and increase of an area under the Q-V curve.

(35) The maximum voltage V.sub.max can be limited by the maximum voltage that can be sustained by a device, i.e., the breakdown voltage, V.sub.bd. Devices designed to increase V.sub.max can allow increased breakdown voltage, V.sub.bd.

(36) Generally the energy stored in a device equals the area under the Q-V curve in a plot such as that shown in FIG. 3. For most materials the capacitance does not depend on Q (i.e., V(Q)=Q/C as indicated by dotted line D in FIG. 3) and the energy stored in the device is given by Equation (II):
E=C*V.sub.max.sup.2(II).

(37) If C is dependent on Q the form of the curve in FIG. 3 may allow an increased stored energy up to C*V.sub.max.sup.2, which is two times the stored energy for most materials.

(38) The area under the Q-V curve may be increased by including a dielectric material with non-linear dependence of permittivity on V.

(39) One or more capacitors of the type shown in FIG. 2A or FIG. 2B may be used in an energy storage cell. By way of example, and not by way of limitation, FIG. 4 a possible implementation of an energy storage cell 40 that includes a capacitive energy storage device, e.g., one or more capacitors 20 of the type shown in FIG. 2B coupled to a DC voltage conversion device 41. Although a single meta-capacitor is depicted for simplicity, in other implementations the capacitive energy storage cell 40 combinations of two, or three or more meta-capacitors in a capacitor network involving various series and and/or parallel combinations may be coupled to the voltage conversion device 41.

(40) In still another implementation, the capacitive energy storage cell 40 may further include a cooling system 42. In some implementations, the cooling can be passive, e.g., using radiative cooling fins on the capacitive energy storage device 40 and DC-voltage conversion device 41. Alternatively, a fluid such as air, water or ethylene glycol can be used as a coolant in an active cooling system. By way of example, and not by way of limitation, the cooling system 30 may include conduits in thermal contact with the capacitive energy storage device 20 and DC-voltage conversion device 41. The conduits are filled with a heat exchange medium, which may be a solid, liquid or gas. In some implementations, the cooling mechanism may include a heat exchanger 44 configured to extract heat from the heat exchange medium. In other implementations, the cooling mechanism 41 may include conduits in the form of cooling fins on the capacitive energy storage device 20 and DC-voltage conversion device 41 and the heat exchange medium is air that is blown over the cooling fins, e.g., by a fan. In another embodiment of the present invention, the heat exchanger 44 may include a phase-change heat pipe configured to carry out cooling. The cooling carried out by the phase-change heat pipe may involve a solid to liquid phase change (e.g., using melting of ice or other solid) or liquid to gas phase change (e.g., by evaporation of water or alcohol) of a phase change material. In yet another implementation, the conduits or heat exchanger 44 may include a reservoir containing a solid to liquid phase change material, such as paraffin wax.

(41) As an aspect of the present disclosure, a capacitive energy storage module 50, e.g., as illustrated in FIG. 5. In the illustrated example, the energy storage module 50 includes two or more energy storage cells 40 of the type described above. Each energy storage cell includes a capacitive energy storage device 46 having one or more capacitors 48 and a DC-voltage converter 41, which may be a buck converter, boost converter, or buck/boost converter. In addition, each module may include a control board 49 containing suitable logic circuitry, e.g., microprocessor, microcontroller, application specific integrated circuit (ASIC), field programmable gate array (FPGA), a complex programmable logic device (CPLD), capable of implementing closed loop control processes and (optionally) a communication interface, as well as an analog to digital converter coupled to sensors on the DC-voltage conversion device 41, e.g., voltage sensors V for the input voltage V.sub.in and the output voltage V.sub.out, current sensors A for current I.sub.sd to/from the capacitive energy storage device 46 and/or current Ivc to/from the DC-voltage conversion device 41, temperature sensors on the capacitive energy storage device and/or DC-voltage conversion device. In some implementations, the control board 49 may be integrated into the DC-voltage conversion device 41. The DC-voltage conversion device 41 may contain a buck regulator, a boost regulator, buck and boost regulators with separate input/outputs, a bidirectional boost/buck regulator, or a split-pi converter and the control board 49 may be configured to maintain a constant output voltage V.sub.out from the DC-voltage conversion device during discharge, and/or charge the capacitor at a more-or-less constant current while maintaining a stable input voltage. The DC-voltage conversion device 41 and the control board 49 may be configured to maintain the voltage in a desired range. By way of example, and not by way of limitation, the control board 49 may be based on a controller for a bidirectional buck/boost converter. In such a configuration, the control board 59 stabilizes the output voltage of the DC-voltage conversion device according to an algorithm forming a suitable control loop. One example of a possible control loop is described in U.S. Patent Application Publication Number 20170237271, which is incorporated herein by reference.

(42) The specifics of operation of the control board 49 are somewhat dependent on the type of buck/boost converter(s) used in the DC-voltage conversion device 41. For example, a buck/boost converter may be a single switch converter having a high-side switch with an input side coupled to the input voltage V.sub.in and an output side coupled to one side of an inductor, the other side of which is connected to the ground or common voltage. A capacitor is coupled across the output voltage V.sub.out. A pulsed switching signal turns the switch on and off. The output voltage depends on the duty cycle of the switching signal. By way of example, the switches may be implanted as gated switch devices, e.g., MOSFET devices, stacked MOSFET devices, IGCT devices, high drain-source voltage SiC MOSFET devices, and the like depending on the voltage and/or current requirements of the DC-voltage converter for the energy storage cell. In the case of gated switching devices, the control board provides the signals to the gate terminals of the switching devices. The control board 49 can configure this type of buck/boost converter to buck or boost by adjusting the duty cycle of the switching signal.

(43) The module 50 may further include an interconnection system that connects the anodes and cathodes of the individual energy storage cells to create a common anode and common cathode of the capacitive energy storage module. In some implementations, the interconnection system may include a parameter bus 52 and power switches PSW. Each energy storage cell 40 in the module 50 may be coupled to the parameter bus 52 via the power switches PSW. These switches allow two or more modules to be selectively coupled in parallel or in series via two or more rails that can serve as the common anode and common cathode. The power switches can also allow one or more energy storage cells to be disconnected from the module, e.g., to allow for redundancy and/or maintenance of cells without interrupting operation of the module. The power switches PSW may be based on solid state power switching technology or may be implemented by electromechanical switches (e.g., relays) or some combination of the two.

(44) In some implementations, the energy storage module 50 further comprises a power meter 54 to monitor power input or output to the module. In some implementations, the energy storage module further comprises a networked control node 55 configured to control power output from and power input to the module. The networked control node 55 allows each module to talk with a system control computer over a high speed network. The networked control node 55 includes voltage control logic circuitry 56 configured to selectively control the operation of each of voltage controller 41 in each of the energy storage cells 40, e.g., via their respective control boards 49. The control node 55 may also include switch control logic circuitry 57 configured to control operation of the power switches PSW. The control boards 49 and power switches PSW may be connected to the control node 55 via a data bus 58. The voltage control and switching logic circuitry in the networked control node 55 may be implemented by one or more microprocessors, microcontrollers, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or complex programmable logic devices (CPLDs). The control node 55 may include a network interface 59 to facilitate transfer of signals between the voltage control logic circuitry 57 and the control boards 49 on the individual energy storage cells 40 and also to transfer signals between the switching logic circuitry 56 and the power switches PSW, e.g., via the data bus 58.

(45) According to yet another aspect of the present disclosure a capacitive energy storage system may include two or more networked capacitive energy storage modules, e.g., of the type shown in FIG. 6. One embodiment of such a capacitive energy storage system 60 is shown in FIG. 6. The system 60 includes two or more energy storage modules 50 of the type shown in FIG. 5. Each capacitive energy storage module 50 includes two or more capacitive energy storage cells 40, e.g., of the type shown in FIG. 4 connected by an interconnection system 52 and controlled by a control node 55. Each capacitive energy storage module may also include a module power meter 54. Although it is not shown in FIG. 6, each control node 55 may include voltage control logic circuitry 56 to control voltage controllers within the individual capacitive energy storage cells 40 and switching logic circuitry 57 to control internal power switches with the module, as described above. In addition, each control node 55 includes an internal data bus 58 and a network interface 59, which may be configured and connected as described above. Power to and from capacitive energy storage modules 50 is coupled to a system power bus 62 via system power switches SPSW, which may be based on solid state power switching technology or may be implemented by electromechanical switches (e.g., relays) or some combination of the two. In some implementations, there may be an inverter (not shown) coupled between each capacitive energy storage module 50 and the system power bus 62 to convert DC power from the module to AC power or vice versa.

(46) The system 60 includes a system controller 66 connected to a system data bus 68. The system controller may include switching control logic 63, voltage control logic 61, and system network interface 64. The voltage control logic 60 may be configured to control the operation of individual DC-voltage controllers within individual cells 40 of individual modules 50. The switching control logic 63 may be configured to control operation of the system power switches SPSW and also the power switches PSW within individual capacitive energy storage modules 50. Voltage control signals may be sent from the voltage control logic 63 to a specific DC-voltage control device 41 within a specific capacitive energy storage cell 40 of a specific capacitive energy storage module through the network interface 64, the system data bus 68, the module network interface 69 of the control node 46 for the specific module, the module data bus 68, and the control board 59 of the individual cells 50.

(47) By way of example, and not by way of limitation, the system controller 66 may be a deterministic controller, an asynchronous controller, or a controller having distributed clock. In one particular embodiment of the capacitive energy storage system 60, the system controller 66 may include a distributed clock configured to synchronize several independent voltage conversion devices in one or more capacitive energy storage cells of one or more of the capacitive energy storage modules 50.

(48) Aspects of the present disclosure allow for electrical energy storage on a much larger scale than possible with conventional electrical energy storage systems. A wide range of energy storage needs can be met by selectively combining one or more capacitors with a DC-voltage conversion devices into a cell, combining two or more cells into a module, or combining two or more modules into systems.

(49) Although the present invention has been described in detail with reference to a particular preferred embodiment, persons possessing ordinary skill in the art to which this invention pertains will appreciate that various modifications and enhancements may be made without departing from the spirit and scope of the claims that follow. Any feature, whether preferred or not may be combined with any other feature whether preferred or not. It should be understood that various alternatives to the embodiments of the invention described herein can be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.