Aluminum polymer capacitors with improved internal conductance and higher breakdown voltage capability.

Abstract

To provide a hybrid capacitor with improved electrical quality and reproductivity, and to provide a method of manufacturing the same.SOLUTION: A capacitor comprises a working element. The working element comprises an anode including a first dielectric body on the anode, a cathode, and a conductive separator provided between the first dielectric body and cathode. The conductive separator comprises a separator and a first conductive polymer. The first conductive polymer at least partially encapsulates the separator. A second conductive polymer at least partially encapsulates the first conductive polymer. The first conductive polymer has a higher conductivity than the second conductive polymer. An anode lead is in electrical contact with the anode, and a cathode lead is in electrical contact with the cathode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a capacitor comprising a solid conductive polymer electrolyte and optionally a liquid electrolyte. In particular, the present invention relates to a capacitor comprising a conductive separator and a method for forming a hybrid capacitor with an improved conductive polymer cover within the interstitial portion of the winding structure. [Background technology]

[0002] Capacitors have historically been defined within two common types: one utilizing a liquid electrolyte and the other a solid electrolyte. Liquid electrolyte capacitors typically have a layered structure, usually consisting of an anode conductor, cathode conductor, and alternating separators wound together and immersed in a liquid electrolyte, all sealed within a container. Solid electrolyte capacitors typically contain a conductive monolith or foil, with a dielectric layer on top, and a solid cathode, such as a conductive polymer or manganese dioxide, on the dielectric. Both common types of capacitors have been widely used in commercial trade, and each has its own unique advantages and disadvantages. For example, liquid electrolyte capacitors have high capacitance and high voltage capability, but typically have poor equivalent series resistance (ESR) due to the poor conductivity of the electrolyte, which is usually around 0.015 S / cm or less. Conductive polymers have high conductivity up to 600 S / cm, so capacitors utilizing conductive polymer cathodes have lower ESRs.

[0003] Conductive polymer cathodes are widely used in commercial trade, at least in part, due to their low equivalent series resistance (ESR) and non-destructive failure modes. This has led to a desire to form hybrid capacitors in which conductive polymers commonly used in solid electrolyte capacitors are utilized within the winding of a liquid electrolyte structure, aiming to achieve the high capacitance and high voltage common to liquid electrolyte capacitors while maintaining the lower ESR common to solid conductive polymer electrolytes. U.S. Patents 8,462,484 and 8,767,377 teach examples of hybrid capacitors.

[0004] The formation of hybrid capacitors typically involves creating an alternating winding structure containing an anode, cathode, and separator, followed by immersion in a conductive polymer. Immersion is achieved by in-situ polymerization of monomers or by diffusion of a pre-formed polymer slurry into the interstitial region of the winding alternating structure.

[0005] The first batch of hybrid capacitors was fabricated using in-situ polymerization of monomers in the presence of an oxidizing agent. In-situ polymerization is a complex method with numerous problems, including contamination of the final product by monomers and oxidizing agents, and the process is unreliable, especially when the in-situ polymer is applied to the winding, due to the complex working environment conditions. These problems were mitigated by using a pre-formed aqueous dispersion or slurry of conductive polymers to immerse the interstitial space of the capacitor winding.

[0006] Improvements to hybrid capacitors are presented in the commonly granted U.S. Patent No. 10,068,713, which eliminates the problem associated with poor migration into the interstitial region of the winding by forming a polymer layer prior to winding. Although this is advantageous, the polymer layer is adjacent and not continuous, which limits the conductivity of the conductive layer. [Disclosure of the Invention] [Problems that the invention aims to solve]

[0007] Despite ongoing efforts, those skilled in the art desire improvements to hybrid capacitors and methods for manufacturing improved hybrid capacitors. This invention provides a method for manufacturing hybrid capacitors with improved electrical quality and reproducibility. [Means for solving the problem]

[0008] The object of the present invention is to provide an improved method for forming a hybrid capacitor and an improved capacitor formed by the improved method.

[0009] A special advantage is the ability to provide hybrid capacitors with improved electrical performance, particularly in terms of both high breakdown voltage capability and improved conductivity of the conductive polymer portion of the capacitor.

[0010] These and other advantages are recognized in a capacitor comprising a working element, the working element comprising an anode having a first dielectric on the anode, a cathode, and a conductive separator provided between the first dielectric and the cathode. The conductive separator comprises a separator and a first conductive polymer, the first conductive polymer at least partially surrounding the separator. A second conductive polymer at least partially surrounding the first conductive polymer, the first conductive polymer having higher conductivity than the second conductive polymer. An anode lead is electrically in contact with the anode, and a cathode lead is electrically in contact with the cathode.

[0011] Further embodiments are provided in a method for forming a capacitor. This method comprises forming a working element, which includes providing an anode comprising a first dielectric and an anode lead, providing a cathode comprising a cathode lead, and forming a conductive separator comprising a separator and a first conductive polymer, wherein the first conductive polymer surrounds the separator at least partially, forming a wound capacitor precursor by winding the anode and cathode with the conductive separator between the first dielectric and the cathode, and introducing a second conductive polymer into the wound capacitor precursor, wherein the second conductive polymer surrounds the first conductive polymer at least partially. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic perspective view of an embodiment of the present invention in which the winding is partially released. [Figure 2] Figure 2 is a schematic cross-sectional view along line 2-2 of Figure 1. [Figure 3] Figure 3 is a schematic representation of an embodiment of the present invention. [Figure 4] Figure 4 is a schematic representation of an embodiment of the present invention. [Figure 5] Figure 5 schematically shows an embodiment of the present invention in a cross-sectional view. [Figure 6] Figure 6 schematically demonstrates the effects of the present invention. [Figure 7] Figure 7 schematically illustrates the effects of the present invention. [Modes for carrying out the invention]

[0013] This invention specializes in a capacitor that includes a solid conductive polymer electrolyte and, optionally, a liquid electrolyte interposed within a wound capacitor, and includes alternating anodes, cathodes, and conductive separators. In particular, the present invention relates to a capacitor and a method of creating an improved capacitor. In particular, this invention enables the manufacture of capacitors with improved performance, specifically, high breakdown voltage and / or lower ESR.

[0014] An element of this invention is to utilize a conductive separator that includes a first conductive polymer layer, and the first conductive polymer layer is at least partially accommodated within a second conductive polymer layer that is applied after winding. The second conductive polymer layer extends from a conductor to a cathode and at least partially accommodates the first conductive polymer layer to form a conductive layer from a dielectric to a cathode, preferably continuously. By incorporating two conductive polymer layers, synergistic improvements in conductivity can be achieved, thus improving the performance of the capacitor.

[0015] In a particularly preferred embodiment, the first conductive polymer layer is formed in-situ. In-situ formed polymers have higher conductivity than separately formed ones and are applied as pre-formed polymers. The pre-formed polymer is applied as a slurry containing either particles of the conductive polymer or solubilized polymer particles. The pre-formed conductive polymer has a high breakdown voltage capability. This combination provides a hybrid capacitor, and through the synergy of different layers, provides a hybrid capacitor with high breakdown voltage capability and low equivalent series resistance (ESR). The low ESR improves the ripple current of the capacitor.

[0016] The present invention will be described with reference to various drawings forming integral and non-limiting components of the present disclosure. Throughout the present disclosure, like elements are numbered accordingly.

[0017] Embodiments of the present invention will be described with reference to Figure 1, where the working element is shown schematically and partially unwound prior to insertion into the container and optionally, preferably, immersion in the liquid electrolyte. In Figure 1, the working element, generally represented by 10, comprises an anode 12 and a cathode 14, with a conductive separator 16 interposed between them. The conductive separator has a first conductive polymer 18 coated on the separator or the separator immersed, preferably saturated with the conductive polymer. Anode leads 20 and cathode leads 22 extend from the wound capacitor and ultimately form electrical conductivity to the circuit. From the description, it will be understood that the anode leads are electrically in contact with the anode, the cathode leads are electrically in contact with the cathode, and are electrically isolated from the anode or anode leads. Tabs 24 and 26 are commonly employed, as known in the art, to electrically connect the anode leads to the anode and the cathode leads to the cathode. The blockage 28, such as adhesive tape, prevents the winding of the operating elements from coming undone during handling and assembly, and afterwards, although this blockage is part of the finished capacitor, it hardly serves any purpose.

[0018] A schematic cross-sectional view along line 2-2 in Figure 1 is shown in Figure 2. In Figure 2, with the understanding that the separator may be immersed in the conductive polymer, and preferably saturated with the conductive polymer, so that the dimensions of the separator do not visibly change due to the inclusion of the conductive polymer, the separator 16 is shown together with the conductive polymer 18, with one side shown for illustrative purposes. The anode 12 and cathode 14 are separated and sandwiched by the separator 16. The separator is preferably a porous material containing a liquid electrolyte that moves freely through the separator.

[0019] Embodiments of the present invention will be described with reference to Figure 3, a portion of which is shown in cross-sectional view. In Figure 3, the anode 12 and cathode 14 have a dielectric 20 and a separator total 22 between them, forming a capacitive coupling. In this specification, one capacitive coupling is shown, with the understanding that the wrapped capacitor has alternating and repeating combinations of anode / dielectric / separator layer / dielectric. In one embodiment, the separator layer includes a separator containing woven fibers 24. The separator is encapsulated at least partially, preferably completely, within a first conductive polymer 18. The first conductive polymer layer is formed from a slurry containing a semipolymerized polymer or by in-situ polymerization. In-situ polymerization techniques are preferred for forming the conductive separator. As will be further discussed herein, a second conductive polymer 26 introduced after wrapping forms a conductive path from the conductor to the cathode in the first polymer layer and encapsulates at least partially, preferably completely, the first conductive polymer. The second conductive polymer is preferably formed by introducing a pre-formed conductive polymer, but is not limited thereto. Optionally and preferably, the liquid electrolyte 28 fills at least partially, preferably completely, the entire interstitial area of ​​the separator.

[0020] The first conductive polymer layer 18 preferably has higher conductivity than the second conductive polymer 26. More preferably, the conductivity of the first conductive polymer is at least 150% to 2500% of the conductivity of the second conductive polymer. As a non-limiting example, if the second conductive polymer has a conductivity of 40 S / cm, the first conductive polymer has a conductivity of at least 60 S / cm to 1000 S / cm. The average particle size of the first conductive polymer is preferably larger than the average particle size of the second conductive polymer.

[0021] The breakdown voltage of the second conductive polymer is higher than that of the first conductive polymer when measured individually using the same method after initial formation or after temperature stress such as 1000 hours at 125°C. More preferably, the breakdown voltage of the second conductive polymer is at least 20% to 700% higher than that of the first conductive polymer.

[0022] The work function of the second conductive polymer is preferably higher than that of the first conductive polymer. More preferably, the work function of the second conductive polymer is at least 0.2 eV to 1.2 eV higher than that of the first conductive polymer. Work function modifiers are well known in the art, as exemplified in U.S. Patents 10,340,091 and 10,204,743.

[0023] Embodiments of the present invention will be described with reference to Figure 4, which schematically shows the capacitor formation process. In Figure 4, the polymer layer 18 is formed on the separator 16 by providing a slurry containing a pre-formed conductive polymer, or by providing an oxidizing agent and a monomer for forming a polymer layer on the separator, which is referred to in the art as in-situ polymerization. The means 42 for providing the oxidizing agent and precursor is not particularly limited herein and is any acceptable method for forming the polymer by in-situ polymerization techniques suitable for demonstrating the present invention. The formation of the polymer on the separator can be carried out as a master, which is then slit in a roll of conductive separator suitable for forming a wound capacitor in 44. The separator can be separated prior to polymer formation, but this is undesirable in terms of ease of manufacture. As is known in the art, a layered roll structure including an anode and a cathode is formed with the conductive separator in between. A dielectric can also be further formed in 46 if necessary. The winding structure is immersed in a second conductive polymer at 48, preferably by introducing a pre-formed polymer into the interstitial portion of the winding, and then dried. In one embodiment, the winding structure immersed in the second conductive polymer is assembled at 50, and then aged and tested at 52. If a liquid electrolyte is not incorporated, the liquid electrolyte is added at 54 using conventional techniques, the capacitor is assembled at 56, and then aged and tested at 58. Assembly includes incorporating the capacitor into the housing and sealing.

[0024] The cathode foil, separator, and anode foil are typically provided as wide rolls and slit to size. The anode foil is preferably etched so that a dielectric is formed thereon. The dielectric may be formed prior to slit formation, in which case the next step is preferably to form the dielectric on the edges of the slits. The separator may be treated with a binder to improve adhesion between the surface and the conductive polymer layer, or to give other specific surface behavior. The conductive separator may be washed and dried before or after the formation or immersion of the conductive polymer layer, and the step of forming or immersing the conductive polymer layer may be repeated several times as needed. Electrical leads or tabs are typically, preferably prior to being cut to length, electrically connected to the anode and cathode, and the leads may be treated with a masking material to protect them from further modification and prepare them for welding to the capacitor terminals.

[0025] The conductive polymer is applied to the separator by any preferred method, including immersion, coating, and spraying. In immersion, the separator is pulled through a series of baths or containers in which monomers and oxidizers are continuously applied in any order. Immersion is preferred for the separator. Coating and spraying may be carried out by any printing technique, including screen printing or spraying of monomers or oxidizers, either sequentially in any order or simultaneously on the surface of the separator. The conductive polymer coating is at least 0.1 mg / cm². 2 It is preferable that the separator be applied in the amount of approximately 0.1 mg / cm³. 2 If the weight falls below this level, the coating weight may not be sufficient to achieve adequate conductivity, resulting in an incomplete coating. Conductive polymer coatings typically have a weight of approximately 10 mg / cm³. 2 It is preferable that the coating be applied in a sufficient amount to achieve the following coating weight: approximately 10 mg / cm³. 2 Beyond a certain point, the thickness of the added coating does not noticeably increase conductivity.

[0026] Using multiple tabs or multiple leads is preferable because it minimizes the resistive effect of the foil. In the case of a single lead, the current must flow from the point where the foil is fully extended to the tab and lead, which negatively impacts the ESR. It is preferable to shorten the length of the conductive path by using multiple anode leads and multiple cathode leads.

[0027] A capacitor is shown in the schematic cross-sectional view of Figure 5. In Figure 5, the capacitor is generally represented by 60, but comprises a working element 62 within a housing 64 as described herein. The housing, referred to in the art as a can, is preferably conductive and may function as a lead or be in electrical contact with the cathode lead 6. The cathode tab 68 is in electrical contact with the housing or the cathode lead. The anode tab 70 is in electrical contact with the anode lead 72. The lid 74 and a seal 76, such as a gasket, seal the housing and prevent atmospheric exchange between the inside of the housing and the atmosphere. In one embodiment, the seal is hermetically sealed.

[0028] The anode is preferably a conductive metal in the form of a foil. The conductive metal is preferably valve metal or a conductive oxide of valve metal. Particularly suitable anodes include valve metals such as tantalum, aluminum, niobium, titanium, zirconium, hafnium, alloys of these elements, or conductive oxides thereof such as NbO. Aluminum is a particularly suitable anode material.

[0029] The oxide film is formed on the anode as a dielectric. The dielectric may be formed using any suitable electrolyte solution, referred to as the forming electrolyte, such as phosphoric acid, phosphate-containing solution, boric acid, borate-containing solution, or ammonium adipate. A formation voltage of approximately 9V to approximately 450V is commonly applied. The formation voltage is typically in the range of 1.5 to 3.5 times the rated voltage of the capacitor.

[0030] The conductive polymer impartment process is typically selected from in-situ polymer formation and impartment of a pre-formed polymer from a slurry by a coating process or the like. In the in-situ process, an immersion solution is applied to the surface, and the immersion solution preferably contains monomers, acidifying agents, dopants, and other adjuvants known to those skilled in the art. The selection of a suitable solvent for this solution is within the realm of the art. Examples of suitable solvents include ketones and alcohols such as acetone, pyridine, tetrahydrofuran, methanol, ethanol, 2-propanol, and 1-butanol. The monomer concentration may be about 1.5% to about 20% by weight, and more preferably about 5% to about 15% by weight, to demonstrate the present invention. Suitable monomers for preparing conductive polymers include, but are not limited to, anili, pyrrole, thiophene, and their derivatives. A suitable monomer is 3,4-ethylenedioxythiophene. The concentration of the oxidizing agent may be about 6% to about 45% by weight, and more preferably about 16% to about 42% by weight, to demonstrate the present invention. Oxidizing agents for preparing conductive polymers include Fe(III) salts of organic and inorganic acids, alkali metal persulfates, ammonium persulfates, and others. A suitable oxidizing agent for demonstrating the present invention is Fe(III) tosylate. The concentration of the dopant may be about 5% to about 30% by weight, and more preferably about 12% to about 25% by weight. Any suitable dopant may be used, such as polystyrene sulfonate, dodecylbenzene sulfonate, p-tosylate, or chloride. A suitable dopant is p-tosylate. The monomer is polymerized by curing the substrate at a temperature of 65°C to about 160°C, more preferably about 80°C to about 120°C. After curing, the polymer layer is preferably washed with deionized water or another solvent.

[0031] A preferred method for introducing a second conductive polymer into the winding is to impart a pre-formed polymer from the slurry after winding. The polymer can be prepared as a slurry or is commercially available as a slurry, and is not particularly limited to this technique, but is preferably subsequently dried. A slurry of 3,4-ethylenedioxythiophene, doped with polystyrene sulfonate or other suitable dopant and polymerized in a solvent to a particle size of 200 nm or less, preferably at least 1 nm to 200 nm, more preferably at least 20 nm to 200 nm, is an example demonstrating the present invention. Particularly preferred slurries are those having a particle size indistinguishable by scattering techniques and referred to as soluble conductive polymers.

[0032] The liquid electrolyte is preferably a solvent containing a supporting salt. Any conventional solvent can be used, and examples of solvents include γ-butyrolactone, sulfolane, ethylene carbonate, propylene carbonate, dimethyl carbonate, ethylmethyl carbonate, acetonitrile, propionitrile, dimethylformamide, diethylformamide, water, silicone oil, polyethylene glycol, and mixtures thereof. A supporting salt is preferred, although it is not required. Examples of supporting salts include inorganic ammonium salts, inorganic amine salts, inorganic alkyl-substituted amide salts, organic ammonium salts, organic amide salts, organic alkyl-substituted amide salts, and derivatives thereof. Any gas absorbent or cathode electrochemical depolarizer can be used. Examples of supported additives include organic alcohols, acids, esters, and nitro derivatives of aromatic derivatives, such as o-, m-, p-nitroanisole, o-, m-, p-nitrobenzoic acid, and o-, m-, p-nitrobenzene alcohol. Particularly preferred hybrid capacitors contain up to 50% by weight of the liquid electrolyte.

[0033] The separator is not particularly limited herein, and the present invention can be demonstrated using any commercially available separator, provided that the material used for the conductive separator is coated with or immersed in a conductive polymer. As an alternative to or addition to the conductive polymer, the separator may be a conductive material itself. As an example of this conductive separator, the separator functions as a skeletal layer of the conductive polymer. The separator can be manufactured in the form of sheets of different dimensions that can be wound onto a roll. An anode foil can function as a support for the separator, wherein the conductive coating is provided on an insulator and the conductive separator layer is formed on the polymer coating, with an insulating layer formed on its surface. Using the anode as a support may minimize operational difficulties. The separator includes a porous conductive layer that creates direct electrical contact between the anode conductive polymer layer and the cathode. Preferably, the separator has a pore volume through which a liquid electrolyte permeates. Other non-conductive materials such as paper or polymer can be used as a support for the conductive polymer. Paper is an example separator because it is widely used and readily available. Unlike conventional capacitors, paper does not need to be carbonized for use as a conductive separator. In the manufacture of conventional capacitors, paper is often carbonized after the formation of the working element to minimize the amount of polymer absorbed by the paper. According to the present invention, this is unnecessary because the separator is coated with or immersed in a conductive polymer to form a conductive separator. The separator may be a fibrous material such as paper fibers, which are physically mixed or crosslinked to form continuous fibers such as paper fibers or layers. The spaces between the fibers may be partially or completely filled with highly conductive components. Paper-based separators can be manufactured by modifying the layers of the finished paper, or by modifying paper with fibers of highly conductive components prior to the formation of paper layers, dispersion of conductive fibers, fragments, or liquid or solid particles or lumps, or deposition of conductive fibers, fragments, or particles.The conductive fibers, fragments, or particles may contain conductive materials such as conductive polymers, carbon black, graphite, metals, etc., or may be composite materials composed of non-conductive cores such as paper and plastic that have been modified with conductive materials such as conductive polymers, carbon black, graphite, metals, etc.

[0034] The conductive separator and the non-conductive separator may contain the same materials, and the conductive separator has a conductive coating thereon or is immersed in a conductor, neither of which is required for the non-conductive separator.

[0035] Particularly suitable separators have a width suitable for the length of the operating element, and a manufacturing process at a width of 1.5 cm to 500 cm is an example demonstrating the present invention. This length is directly related to the lengths and widths of the cathode and anode because the capacity functions as an anode and the cathode overlaps, and is therefore selected based on the desired capacity. Examples demonstrating the present invention are separators with a length of 0.1 m to 400 m and a thickness of 10 μm to 300 μm.

[0036] The conductive polymer is preferably selected from polyaniline, polypyrrole, and polythiophene, or substituted derivatives thereof.

[0037] Particularly suitable conductive polymers are represented by Formula I,

[0038]

Chemical formula

[0039] In the formula, R 1 and R 2 are selected to inhibit polymerization at the β-site of the ring. It is most preferred that only polymerization at the α-site can proceed. Therefore, R 1 and R 2 are preferably not hydrogen. R 1 and R 2It is preferable that it is an α-director. Therefore, an ether bond is preferable to an alkyl bond. To avoid steric hindrance, it is most preferable that the group be small. For these reasons, R 1 and R 2 Both are most preferably -O-(CH2)2-O-. In formula I, X is S, N, or O, and X is most preferably S. A particularly preferred conductive polymer is polymerized 3,4-polyethylenedioxythiophene (PEDOT).

[0040] R 1 and R 2 These are independently linear or branched C1-C 16 Alkyl or C2-C 18 This represents an alkoxyalkyl group, or an alkyl group of C1-C6, an alkoxy group of C1-C6, a halogen, or OR 3 C3-C8 cycloalkyl, phenyl, or benzyl that is not substituted or is substituted, or R 1 and R 2 Both are C1-C6 alkyl, C1-C6 alkoxy, halogen, C3-C8 cycloalkyl, phenyl, benzyl, C1-C4 alkylphenyl, C1-C4 alkoxyphenyl, halophenyl, C1-C4 alkylbenzyl, C1-C4 alkoxybenzyl or halobenzyl, or straight-chain C1-C6 alkylenes that are either unsubstituted or substituted with a 5-membered, 6-membered, or 7-membered heterogeneous structure containing two oxygen elements. 3 This consists of hydrogen, a straight chain, or a branched C1-C chain. 16 Alkyl, or C2-C 18 It is preferable that it represents an alkoxyalkyl group, or a C3-C9 cycloalkyl group, phenyl group, or benzyl group that is not substituted with or is substituted with a C1-C6 alkyl group. In a particularly preferred embodiment, R 3 Formula I comprises an anionic group with a corresponding cationic group, and is essentially a conductive polymer, but does not need to be a counterion, which is called a self-doped polymer.

[0041] Conventionally, various dopants can be incorporated into the polymer during the weighting process. Dopants can be derived from various acids or salts, including aromatic sulfonic acids, aromatic polysulfonic acids, organic sulfonic acids with hydroxyl groups, organic sulfonic acids with carboxylhydroxyl groups, alicyclic sulfonic acids, benzoquinone sulfonic acids, benzenedisulfonic acid, sulfosalicylic acid, sulfoisophthalic acid, camphor sulfonic acid, benzoquinone sulfonic acid, dodecylbenzenesulfonic acid, and toluenesulfonic acid. Other suitable dopants include sulfoquinone, anthracene monosulfonic acid, substituted naphthalene monosulfonic acid, substituted benzenesulfonic acid, or heterocyclic sulfonic acid, as exemplified in U.S. Patent No. 6,381,121, which is incorporated herein by reference.

[0042] Binders and crosslinking agents can also be incorporated into the conductive polymer layer as desired. Suitable materials include poly(vinyl acetate), polycarbonate, poly(butyl butyrate), polyacrylates, polymethacrylates, polystyrene, polyacrylonitrile, poly(vinyl chloride), polybutadiene, polyisoprene, polyethers, polyesters, silicones, and copolymers of pyrrole / acrylate, vinyl acetate / acrylate, and ethylene / vinyl acetate.

[0043] Other adjuvants, coatings, and related elements can be incorporated into the capacitor as are known in the art and without departing from the present invention. As described above, these include, in a non-limiting overview, protective layers, multiple capacitance levels, terminals, leads, etc.

[0044] The capacitor of the present invention has a rated voltage of at least 15 volts to 400 volts or less, more preferably 500 volts or less, and this rated voltage is about 50% of the dielectric formation voltage. [Examples]

[0045] A cellulose fiber-based material with a density of 0.35 g / cm³ and a thickness of 50 μm was used as a separator and treated with commercially available polymerized 3,4-polyethylenedioxythiophene, which was provided as a slurry for forming at least partially encapsulated control conductive separators. The control separator was immersed twice in the slurry, and the slurry was dried first at 80°C and then at 150°C to form a solid coating. The same cellulose fiber separator was treated by immersion in a solution containing iron tosylate as an oxidizing agent, drying at ambient temperature for 3 hours, and then immersion in a solution containing 3,4-ethylenedioxythiophene monomer. Polymerization of the monomer proceeded at ambient temperature for 3 hours and then at 40°C for 3 hours to form polymerized 3,4-polyethylenedioxythiophene, thereby forming the conductive separator of the present invention. The conductive separator of the present invention was washed with ethanol and cured by drying at 40°C for 1 hour and then at 125°C for 3 hours. The resistance of each conductive separator was tested multiple times using the same probe. The result showed that the conductive separator of the present invention had a resistance of 4.6 (±0.44) Ω, while the control conductive separator had a resistance of 8.1 (±0.49) Ω. This demonstrated that the conductive separator of the present invention improves conductivity by approximately 76% compared to the control.

[0046] To demonstrate the present invention, three capacitors were fabricated. Each was based on a 720Vf aluminum foil, which had a dielectric formed up to 500V in a boric acid solution after forming a slit. Capacitor 1 was formed by in-situ polymer formation on the dielectric, including polymerization of 3,4-ethylenedioxythiophene with iron tosylate. Capacitor 2 was prepared with the same conductive separator as capacitor 1, and after assembly, a polymer slurry of polymerized 3,4-polyethylenedioxythiophene was incorporated as a second conductive polymer. Capacitor 3 was prepared identically to capacitor 2, except that it contained a high-voltage liquid electrolyte (Vs-450V). The results are shown in Figures 6 and 7. In Figure 6, the information trajectory represents the result for capacitor 1, and the lower trajectory represents the result for capacitor 3. Figure 7 shows the result for capacitor 2.

[0047] As shown in Figures 6 and 7, capacitors 2 and 3 correspond to the configuration shown in Figure 3, and their voltage capability for the prototype was higher than 200V. The first spark occurred at 300V for capacitor 2, but the leakage current remained stable, while multiple sparks with unstable currents occurred at 400V. In this structure, 300V was the voltage limit. In the sample of the present invention, good leakage current performance was demonstrated, and multiple faults were observed and detected as current instability at 400V. The complete field capacitor structure demonstrated worse results. First, the leakage current was almost twice as high as that of the capacitor of the present invention, even at very low voltages such as 10V to 30V. At 50V, the leakage voltage began to rise significantly, which can already be considered the voltage limit. At 100V, capacitor 2 failed in short-circuit fault mode.

[0048] While the present invention has been described with reference to preferred embodiments, it is not limited thereto. Those skilled in the art will recognize additional embodiments and improvements that are not specifically described herein but fall within the scope of the present invention as specifically described in the invoice attached herein.

Claims

1. It is a capacitor, The operating element comprises an operating element, The anode includes a first dielectric on the anode, Cathode and, At least one of the anode or the cathode is made of valve metal, A conductive separator between the first dielectric and the cathode, wherein the conductive separator has a layered structure comprising a separator and a first conductive polymer, the first conductive polymer being a first layer on the separator and at least partially sealing the separator, A second conductive polymer, wherein the second conductive polymer is a second layer coated on the first conductive polymer, at least partially encapsulating the first conductive polymer, and the first conductive polymer has higher conductivity than the second conductive polymer. an anode lead that is in electrical contact with the anode, The cathode is electrically in contact with a cathode lead, A capacitor in which the first conductive polymer or the second conductive polymer is made of poly-3,4-ethylenedioxythiophene.

2. The capacitor according to claim 1, wherein the first conductive polymer is formed from a slurry of pre-formed conductive polymers or from a highly conductive polymer formed by in-situ polymerization.

3. The capacitor according to claim 1, wherein the second conductive polymer is formed from a slurry of pre-formed conductive polymers.

4. The capacitor according to claim 1, wherein the first conductive polymer has a first conductivity, the second conductive polymer has a second conductivity, and the first conductivity is 150% to 2500% of the second conductivity.

5. The capacitor according to claim 1, wherein the first conductive polymer has a first breakdown voltage, and the second conductive polymer has a second breakdown voltage, the second breakdown voltage being higher than the first breakdown voltage.

6. The capacitor according to claim 5, wherein the second breakdown voltage is 120% to 700% of the first breakdown voltage.

7. The capacitor according to claim 1, wherein the first conductive polymer has a first work function, and the second conductive polymer has a second work function, the second work function being higher than the first work function.

8. The capacitor according to claim 7, wherein the second work function is 0.2 eV to 1.2 eV higher than the first work function.

9. The capacitor according to claim 1, wherein the first conductive polymer has an average particle size larger than the average particle size of the second conductive polymer.

10. The capacitor according to claim 1, further comprising a liquid electrolyte between the dielectric and the cathode.

11. The capacitor according to claim 10, wherein the liquid electrolyte is contained in an amount up to 50% by weight of the capacitor.

12. The capacitor according to claim 1, wherein the first conductive polymer is coated onto the separator, or the first conductive polymer immerses the separator.

13. The capacitor according to claim 1, wherein the first conductive polymer or the second conductive polymer is a self-doped polymer.

14. The capacitor according to claim 1, comprising a plurality of anode leads or a plurality of cathode leads.

15. The capacitor according to claim 1, wherein the valve metal is selected from the group consisting of tantalum, aluminum, niobium, titanium, zirconium, hafnium, alloys of these elements, and conductive oxides thereof.

16. The capacitor according to claim 15, wherein the valve metal is aluminum.

17. The separator is 0.1 mg / cm³ ２ ~10 mg / cm² ２ The capacitor according to claim 1, having a first conductive polymer coating.

18. A capacitor according to claim 1, having a rated voltage of 15 volts to 500 volts.

19. A method for forming a capacitor, The following includes forming an operating element, which means: The anode is provided, which includes a first dielectric and an anode lead. A cathode equipped with a cathode lead is provided, At least one of the anode or the cathode is made of valve metal, The present invention relates to forming a conductive separator comprising a separator and a first conductive polymer, wherein the first conductive polymer at least partially surrounds the separator, and the separator is composed of the first conductive polymer coated on the separator, or the first conductive polymer immerses the separator. A wound capacitor precursor is formed by winding the anode and the cathode with the conductive separator sandwiched between the first dielectric and the cathode, The method includes introducing a second conductive polymer into the wrapped capacitor precursor, wherein the second conductive polymer at least partially surrounds the first conductive polymer. A method for forming a capacitor, wherein the first conductive polymer has higher conductivity than the second conductive polymer.

20. The method for forming a capacitor according to claim 19, wherein the first conductive polymer is formed by in-situ polymerization technology.

21. A method for forming a capacitor according to claim 19, comprising introducing a slurry into the winding capacitor precursor, wherein the slurry comprises a pre-formed conductive polymer.

22. A method for forming a capacitor according to claim 19, wherein the first conductive polymer has a first conductivity, the second conductive polymer has a second conductivity, and the first conductivity is 150% to 2500% of the second conductivity.

23. The method for forming a capacitor according to claim 19, wherein the first conductive polymer has a first breakdown voltage, the second conductive polymer has a second breakdown voltage, and the second breakdown voltage is higher than the first breakdown voltage.

24. The method for forming a capacitor according to claim 23, wherein the second breakdown voltage is 120% to 700% of the first breakdown voltage.

25. The method for forming a capacitor according to claim 19, wherein the first conductive polymer has a first work function, and the second conductive polymer has a second work function, the second work function being higher than the first work function.

26. The method for forming a capacitor according to claim 25, wherein the second work function is 0.2 eV to 1.2 eV higher than the first work function.

27. A method for forming a capacitor according to claim 19, further comprising adding a liquid electrolyte to the operating element, wherein the liquid electrolyte is contained between the dielectric and the cathode.

28. The conductive separator is 0.1 mg / cm³ ２ ~10 mg / cm² ２ A method for forming a capacitor according to claim 19, having a first conductive polymer coating weight.

29. The method for forming a capacitor according to claim 19, wherein at least one of the first conductive polymer or the second conductive polymer comprises a polymer selected from the group consisting of polyaniline, polythiophene, and polypyrrole.

30. The method for forming a capacitor according to claim 29, wherein the polythiophene is poly-3,4-ethylenedioxythiophene.

31. The method for forming a capacitor according to claim 29, wherein the first conductive polymer or the second conductive polymer is a self-doped polymer.

32. A method for forming a capacitor according to claim 19, comprising forming a plurality of anode leads or a plurality of cathode leads.

33. The method for forming a capacitor according to claim 19, wherein the valve metal is selected from the group consisting of tantalum, aluminum, niobium, titanium, zirconium, hafnium, alloys of these elements, and conductive oxides thereof.

34. The method for forming a capacitor according to claim 33, wherein the valve metal is aluminum.

35. A method for forming a capacitor according to claim 19, having a rated voltage of 15 volts to 500 volts.

36. The method for forming a capacitor according to claim 19, wherein the first conductive polymer has an average particle size larger than the average particle size of the second conductive polymer.

37. The method for forming a capacitor according to claim 36, wherein the second conductive polymer is a soluble conductive polymer.

38. The method for forming a capacitor according to claim 36, wherein the second conductive polymer has a particle size of 200 nm or less.

39. The method for forming a capacitor according to claim 36, wherein the average particle size of the second conductive polymer is at least 1 nm.

40. The method for forming a capacitor according to claim 39, wherein the average particle size of the second conductive polymer is at least 20 nm.

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