High voltage solid state capacitor and method of making same

Abstract

The application belongs to the field of energy storage device manufacturing, and discloses a high-voltage solid capacitor and a preparation method thereof, which comprises a core package and a shell, and the core package comprises an anode foil, a positive terminal, a cathode foil, a negative terminal, a dielectric material, a solid electrolyte and electrolytic paper; wherein the anode foil is an etched aluminum foil, the cathode foil is an aluminum foil, and the dielectric material is a rigid polymeric high-molecular compound coated barium titanate powder composite epoxy resin; the high-voltage solid capacitor prepared by the application has good voltage resistance, small leakage current and long service life.

Description

Technical Field

[0001] This invention belongs to the field of energy storage device manufacturing technology, specifically relating to a high-voltage solid capacitor and its preparation method. Background Technology

[0002] As a crucial basic electronic component, capacitors are widely used in energy, electronics, power, and military fields. They consist of two electrodes and a dielectric material between them, primarily functioning as energy storage and release, filtering, coupling, bypassing, and tuning. Based on the dielectric properties, capacitors can be classified into inorganic dielectric capacitors, organic dielectric capacitors, electrolytic capacitors, solid-state capacitors, and special capacitors.

[0003] Solid-state capacitors, developed to overcome the inherent defects of electrolytic capacitors, rely on the use of high-conductivity solid conductive polymers to replace liquid electrolytes as the cathode material, resulting in significant performance improvements. The electronic conductivity of solid conductors is several orders of magnitude higher than that of liquid ionic conductors, giving solid-state capacitors extremely low equivalent series resistance and equivalent series inductance, leading to high ripple current handling capacity, lower self-heating, and excellent high-frequency characteristics. Furthermore, the absence of electrolyte volatilization significantly improves the stability and lifespan of solid-state capacitors at high temperatures, and their operating temperature range is wider. However, the relatively low breakdown voltage of conductive polymers results in poor voltage withstand capability for solid-state capacitors.

[0004] Ceramic / polymer dielectric composites have attracted considerable attention due to the excellent processability and high breakdown electric field resistance of polymers, as well as their high dielectric constant. However, the surface energy difference between the inorganic filler and the polymer matrix leads to agglomeration, resulting in numerous pores and voids within the composite material, which affects its dielectric properties. Furthermore, the electrical property differences between the filler and the substrate polymer cause uneven electric field distribution and complex interfacial polarization, hindering the improvement of energy storage density. Moreover, the thermal effect of epoxy resin causes thermal expansion, which can lead to disordered dispersion of ceramic particles and a significant decrease in the dielectric constant. Summary of the Invention

[0005] To address the shortcomings mentioned in the background section, the present invention aims to provide a high-voltage solid-state capacitor and its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-voltage solid-state capacitor includes a core and a casing, wherein the core includes an anode foil, a positive terminal, a cathode foil, a negative terminal, a dielectric material, a solid electrolyte, and electrolytic paper;

[0008] The anode foil is an etched aluminum foil;

[0009] The cathode foil is aluminum foil;

[0010] The dielectric material is a rigid polymer compound coated with barium titanate powder and epoxy resin.

[0011] Preferably, the method for preparing the dielectric material includes the following steps:

[0012] A1: Mix vinyl terephthalic acid, dichloromethane, oxaloyl chloride, and N,N-dimethylformamide and react for 4-8 h, then rotary evaporate to obtain an intermediate; mix the intermediate, p-aminophenol, and tetrahydrofuran, react in an ice-water bath for 1-3 h, then at room temperature for 6-10 h, and then rotary evaporate to obtain a rigid organic compound.

[0013] A2: Surface-aminated barium titanate powder, activated 2-cyanopropyl-2-ylbenzodisulfide, and tetrahydrofuran are mixed and stirred for 10-14 h, centrifuged, and vacuum dried to obtain modified barium titanate. Modified barium titanate, rigid structure organic compound, azobisisobutyronitrile, and chlorobenzene are mixed and added to a reaction vessel. The mixture is heated to 70-90℃ under a nitrogen atmosphere and stirred and kept at the temperature for 4-8 h. Tetrahydrofuran is added, centrifuged, and vacuum dried to obtain coated barium titanate.

[0014] A3: Epoxy resin, coated barium titanate, anhydrous ethanol, dispersant, curing agent, and accelerator are mixed and dispersed for 24 hours. The mixture is then dried in a vacuum oven to remove air bubbles and added to a mold to obtain a dielectric material by hot pressing.

[0015] Preferably, the weight ratio of vinyl terephthalic acid and oxaloyl chloride in A1 is 6-8:9-10; and the weight ratio of intermediate to p-aminophenol is 5:5-6.

[0016] Preferably, the weight ratio of surface-aminated barium titanate powder and activated 2-cyanopropyl-2-benzodisulfide in A2 is 5:1.5-3, and the weight ratio of modified barium titanate, rigid-structure organic compound and azobisisobutyronitrile is 5:1.5-2:0.01.

[0017] Preferably, the weight ratio of epoxy resin, coated barium titanate, anhydrous ethanol, dispersant, curing agent, and accelerator in A3 is 80-85:15-20:150:0.5-3:12-18:1-2.

[0018] The dispersant is a phosphate ester dispersant;

[0019] The curing agent is phthalic anhydride curing agent;

[0020] The accelerator is 2-ethyl-4-methylimidazole.

[0021] Preferably, the method for preparing the activated 2-cyanopropyl-2-ylbenzodisulfide includes the following steps:

[0022] 2-Cyanopropyl-2-ylbenzodisulfide, 2-mercaptothiazoline, N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, and dichloromethane were added to a reaction flask and mixed. The mixture was stirred for 10-15 hours, filtered, and rotary evaporated to obtain activated 2-cyanopropyl-2-ylbenzodisulfide.

[0023] The weight ratio of 2-cyanopropyl-2-ylbenzodisulfide, 2-mercaptothiazoline, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 8:6:3.5-4:0.1-0.15.

[0024] Preferably, the method for preparing surface-aminated barium titanate powder includes the following steps:

[0025] Add barium titanate powder and hydrogen peroxide solution to a reaction flask, disperse by ultrasonication, heat under reflux and stir for 4-8 hours, centrifuge, wash with deionized water, and dry to obtain barium titanate powder with surface hydroxylation.

[0026] Surface-hydroxylated barium titanate powder, aminosilane coupling agent, and ethanol aqueous solution are added to a reaction vessel, stirred and dispersed, and dried to obtain surface-aminolated barium titanate powder.

[0027] The concentration of hydrogen peroxide solution is 27-32 wt%, and the addition ratio of barium titanate powder to hydrogen peroxide is 5-15 g: 100 mL;

[0028] The concentration of anhydrous ethanol in the aqueous ethanol solution is 87-90 vol; the addition ratio of surface-hydroxylated barium titanate powder, aminosilane coupling agent, and aqueous ethanol solution is 5 g: 0.5-2 g: 100 mL.

[0029] Preferably, the method for preparing the etched aluminum foil includes the following steps:

[0030] Aluminum foil is cleaned with anhydrous ethanol, then immersed in an etching solution at a controlled temperature of 50-70℃ for 2-5 minutes. After washing with deionized water and drying, etched aluminum foil is obtained.

[0031] The etching solution contains the following components by weight: 5-15 parts concentrated hydrochloric acid, 2-8 parts concentrated sulfuric acid, 1-5 parts ammonium chloride, and 72-92 parts deionized water, wherein the concentration of concentrated hydrochloric acid is 36-38 wt% and the concentration of concentrated sulfuric acid is 95-98 wt%.

[0032] Preferably, a method for manufacturing a high-voltage solid-state capacitor includes the following steps:

[0033] S1: Cut each component inside the core package into the specified shape and size, then connect the anode foil to the positive terminal and the cathode foil to the negative terminal, and then assemble them in the order of anode foil, positive terminal, dielectric material, electrolytic paper, negative terminal and cathode foil to obtain the core package semi-finished product;

[0034] S2: Immerse in an impregnation solution containing conductive polymer monomers, heat to cure, and obtain a core package;

[0035] S3: The core is encapsulated in an aluminum casing, and the positive and negative terminals are led out of the aluminum casing. The casing is then vacuum sealed to obtain a high-voltage solid-state capacitor.

[0036] Preferably, the method for preparing the impregnation solution containing conductive polymer monomers includes the following steps: mixing 5-8 parts of sodium poly(p-styrene sulfonate) with 85-90 parts of deionized water, adding 1-2 parts of 3,4-ethylenedioxythiophene, adjusting the pH to 2-3, adding 2-3 parts of ammonium persulfate and 0.4-1 parts of ferric sulfate, and stirring to disperse evenly to obtain the impregnation solution containing conductive polymer monomers.

[0037] The beneficial effects of this invention are:

[0038] The dielectric material used in this invention is a rigid polymer compound coated with barium titanate powder and epoxy resin. First, an intermediate is obtained by reacting vinyl terephthalic acid with oxaloyl chloride. Then, the intermediate is reacted with p-aminophenol to obtain a rigid organic compound. The activated 2-cyanopropyl-2-ylbenzodisulfide...

[0039] Modified barium titanate is obtained by grafting onto the surface of aminated barium titanate. Finally, a rigid organic compound is copolymerized to form a coating on the surface of the modified barium titanate by initiating carbon-carbon double bonds. The coated barium titanate is then combined with epoxy resin to obtain a dielectric material.

[0040] Rigid organic compounds, as monomers in liquid crystal polymers, possess characteristics such as low dielectric loss, high insulation, and excellent high-frequency stability. Grafting these compounds onto surface-aminated barium titanate powder and then copolymerizing them forms a coating. Due to the strong steric effect of the coating layer's side chains, the main chain is forced to straighten, resulting in a columnar nematic phase in the polymer. This gives the molecular chains rigidity, effectively improving the breakdown electric field resistance of barium titanate composite epoxy resin and reducing the thermal expansion effect of the epoxy resin. Furthermore, the phenolic groups on the polymer can crosslink with the epoxy resin, greatly improving the dispersibility of barium titanate and fully leveraging its excellent high dielectric constant, thus enhancing the electrical performance of the capacitor. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1: The method for preparing dielectric materials includes the following steps:

[0043] A1: 0.6 g vinyl terephthalic acid, 5 mL dichloromethane, 0.9 g oxaloyl chloride, and 0.1 mL N,N-dimethylformamide were mixed and reacted for 4 h, followed by rotary evaporation to obtain an intermediate; 0.5 g of the intermediate, 0.5 g p-aminophenol, and 10 mL tetrahydrofuran were mixed and reacted in an ice-water bath for 1 h, then at room temperature for 6 h, followed by rotary evaporation to obtain a rigid organic compound;

[0044] A2: 5g of surface-aminated barium titanate powder, 1.5g of activated 2-cyanopropyl-2-ylbenzodisulfide, and 15mL of tetrahydrofuran were mixed and stirred for 10h. After centrifugation and vacuum drying, modified barium titanate was obtained. 5g of modified barium titanate, 1.5g of rigid-structure organic compound, 0.01g of azobisisobutyronitrile, and 15mL of chlorobenzene were mixed and added to a reaction vessel. The mixture was heated to 70℃ under a nitrogen atmosphere and stirred and kept at the temperature for 4h. Tetrahydrofuran was added, centrifuged, and vacuum dried to obtain coated barium titanate.

[0045] A3: 26.7g epoxy resin (Dow DER661), 5g coated barium titanate, 50g anhydrous ethanol, 0.2g BYK-9010, 4g methyltetrahydrophthalic anhydride, and 0.3g 2-ethyl-4-methylimidazolium were mixed and dispersed for 24h. The mixture was then dried in a vacuum oven to remove air bubbles and added to a mold to obtain a dielectric material by hot pressing.

[0046] The preparation method of activated 2-cyanopropyl-2-ylbenzodisulfide includes the following steps: 8g of 2-cyanopropyl-2-ylbenzodisulfide, 6g of 2-mercaptothiazoline, 3.7g of N,N'-dicyclohexylcarbodiimide, 0.12g of 4-dimethylaminopyridine, and dichloromethane are added to a reaction flask and mixed. The mixture is stirred for 12h, filtered, and rotary evaporated to obtain activated 2-cyanopropyl-2-ylbenzodisulfide.

[0047] The preparation method of surface-aminated barium titanate powder includes the following steps: 5g of barium titanate powder and 100mL of 30wt% hydrogen peroxide are added to a reaction flask, ultrasonically dispersed for 30min, heated to 105℃ and stirred under reflux for 6h, centrifuged three times and washed with deionized water, and dried to obtain surface-hydroxylated barium titanate powder; 5g of surface-hydroxylated barium titanate powder, 1.3g of aminosilane coupling agent and 100mL of 89vol% ethanol aqueous solution are added to a reaction vessel, stirred and dispersed, and dried to obtain surface-aminated barium titanate powder.

[0048] The preparation method of etched aluminum foil includes the following steps: 10g of 37% concentrated hydrochloric acid, 5g of 96% concentrated sulfuric acid, 3g of ammonium chloride and 82g of deionized water are mixed to obtain an etching solution. The aluminum foil is cleaned with anhydrous ethanol, and then immersed in the etching solution at a controlled temperature of 60℃ for 3 minutes. After washing with deionized water and drying, the etched aluminum foil is obtained.

[0049] The preparation method of the impregnation solution containing conductive polymer monomers includes the following steps: 6.5g of sodium poly(p-styrene sulfonate) and 88.8g of deionized water are mixed, 1.5g of 3,4-ethylenedioxythiophene is added, the pH is adjusted to between 2 and 3, 2.5g of ammonium persulfate and 0.7g of ferric sulfate are added, and the mixture is stirred and dispersed evenly to obtain the impregnation solution containing conductive polymer monomers.

[0050] Example 2: The method for preparing dielectric materials includes the following steps:

[0051] A1: 0.7 g vinyl terephthalic acid, 5 mL dichloromethane, 0.9 g oxaloyl chloride, and 0.1 mL N,N-dimethylformamide were mixed and reacted for 6 h, followed by rotary evaporation to obtain the intermediate; 0.55 g p-aminophenol, 0.5 g the intermediate, and 10 mL tetrahydrofuran were mixed and reacted in an ice-water bath for 2 h, then at room temperature for 8 h, followed by rotary evaporation to obtain a rigid organic compound;

[0052] A2: 5g of surface-aminated barium titanate powder prepared in Example 1, 2.3g of activated 2-cyanopropyl-2-ylbenzodisulfide prepared in Example 1, and 15mL of tetrahydrofuran were mixed and stirred for 12h, centrifuged, and vacuum dried to obtain modified barium titanate. 5g of modified barium titanate, 1.8g of rigid-structure organic compound, 0.01g of azobisisobutyronitrile, and 15mL of chlorobenzene were mixed and added to a reaction vessel. The mixture was heated to 80℃ under a nitrogen atmosphere and stirred and kept at that temperature for 6h. Tetrahydrofuran was added, centrifuged, and vacuum dried to obtain coated barium titanate.

[0053] A3: 23.6g epoxy resin (Dow DER661), 5g coated barium titanate, 43g anhydrous ethanol, 0.5g BYK-9010, 4.3g methyltetrahydrophthalic anhydride, and 0.4g 2-ethyl-4-methylimidazolium were mixed and dispersed for 24 hours. The mixture was then dried in a vacuum oven to remove air bubbles and added to a mold to obtain a dielectric material by hot pressing.

[0054] Example 3: The method for preparing dielectric materials includes the following steps:

[0055] A1: 0.8 g vinyl terephthalic acid, 5 mL dichloromethane, 0.9 g oxaloyl chloride, and 0.1 mL N,N-dimethylformamide were mixed and reacted for 8 h, followed by rotary evaporation to obtain the intermediate; 0.6 g p-aminophenol, 0.5 g the intermediate, and 10 mL tetrahydrofuran were mixed and reacted in an ice-water bath for 3 h, followed by reaction at room temperature for 10 h, followed by rotary evaporation to obtain a rigid organic compound;

[0056] A2: 5g of surface-aminated barium titanate powder prepared in Example 1, 3g of activated 2-cyanopropyl-2-ylbenzodisulfide prepared in Example 1, and 15mL of tetrahydrofuran were mixed and stirred for 14h, centrifuged, and vacuum dried to obtain modified barium titanate. 5g of modified barium titanate, 2g of rigid structure organic compound, 0.01g of azobisisobutyronitrile, and 15mL of chlorobenzene were mixed and added to a reaction vessel. The mixture was heated to 90℃ under a nitrogen atmosphere and stirred and kept at that temperature for 8h. Tetrahydrofuran was added, centrifuged, and vacuum dried to obtain coated barium titanate.

[0057] A3: 21.3g epoxy resin (Dow DER661), 5g coated barium titanate, 37.5g anhydrous ethanol, 0.75g BYK-9010, 4.5g methyltetrahydrophthalic anhydride, and 0.5g 2-ethyl-4-methylimidazolium were mixed and dispersed for 24 hours. The mixture was then dried in a vacuum oven to remove air bubbles and added to a mold to obtain a dielectric material by hot pressing.

[0058] Example 4: A high-voltage solid-state capacitor includes a core and a casing. The core includes an etched foil, a positive terminal, an aluminum foil, a negative terminal, a dielectric material, a solid electrolyte, and electrolytic paper. The preparation method includes the following steps:

[0059] S1: Cut each component in the core package into a specified shape and size, then connect the etched aluminum foil prepared in Example 1 to the positive terminal and the aluminum foil to the negative terminal, and then assemble them in the order of etched aluminum foil, positive terminal, dielectric material prepared in Example 1, electrolytic paper, negative terminal and aluminum foil to obtain the core package semi-finished product.

[0060] S2: Immerse the core package semi-finished product in the immersion solution containing conductive polymer monomers prepared in Example 1 for 10 min, and cure it at 50°C for 8 h to obtain the core package;

[0061] S3: The core is encapsulated in an aluminum casing, and the positive and negative terminals are led out of the aluminum casing. The casing is then vacuum sealed to obtain a high-voltage solid-state capacitor.

[0062] Example 5: A high-voltage solid-state capacitor, compared with Example 4, except that the dielectric material added in Example 4 is replaced in equal amounts with the dielectric material prepared in Example 2, and the remaining components and preparation methods are completely the same as in Example 4.

[0063] Example 6: A high-voltage solid-state capacitor, compared with Example 4, except that the dielectric material added in Example 4 is replaced in equal amounts with the dielectric material prepared in Example 3, and the remaining components and preparation methods are completely the same as in Example 4.

[0064] Comparative Example 1: A high-voltage solid-state capacitor, which, compared with Example 4, is obtained by replacing the dielectric material added in Example 4 with an equal amount of the dielectric material prepared in Comparative Example 1, while the remaining components and preparation methods are completely consistent with Example 4.

[0065] The preparation method of dielectric materials includes the following steps:

[0066] A1: 0.7 g vinyl terephthalic acid, 5 mL dichloromethane, 0.9 g oxaloyl chloride, and 0.1 mL N,N-dimethylformamide were mixed and reacted for 6 h, followed by rotary evaporation to obtain the intermediate; 0.55 g p-aminophenol, 0.5 g the intermediate, and 10 mL tetrahydrofuran were mixed and reacted in an ice-water bath for 2 h, then at room temperature for 8 h, followed by rotary evaporation to obtain a rigid organic compound;

[0067] A2: 5g of surface-aminated barium titanate powder prepared in Example 1, 2.3g of activated 2-cyanopropyl-2-ylbenzodisulfide prepared in Example 1, and 15mL of tetrahydrofuran were mixed and stirred for 12h, centrifuged, and vacuum dried to obtain modified barium titanate. 5g of modified barium titanate, 1.8g of rigid-structure organic compound, and 15mL of chlorobenzene were mixed and added to a reaction vessel. The mixture was heated to 80℃ under a nitrogen atmosphere and stirred and kept at that temperature for 6h. Tetrahydrofuran was added, centrifuged, and vacuum dried to obtain grafted barium titanate.

[0068] A3: 23.6g epoxy resin (Dow DER661), 5g grafted barium titanate, 43g anhydrous ethanol, 0.5g BYK-9010, 4.3g methyltetrahydrophthalic anhydride, and 0.4g 2-ethyl-4-methylimidazolium were mixed and dispersed for 24 hours. The mixture was then dried in a vacuum oven to remove air bubbles and added to a mold to obtain a dielectric material by hot pressing.

[0069] Comparative Example 2: A high-voltage solid-state capacitor, which, compared with Example 4, only replaces the dielectric material added in Example 4 with the dielectric material prepared in Comparative Example 2 in equal amounts, while the remaining components and preparation methods are completely consistent with Example 4.

[0070] The preparation method of dielectric materials includes the following steps:

[0071] A1: 0.7 g vinyl terephthalic acid, 5 mL dichloromethane, 0.9 g oxaloyl chloride, and 0.1 mL N,N-dimethylformamide were mixed and reacted for 6 h, followed by rotary evaporation to obtain the intermediate; 0.55 g p-aminophenol, 0.5 g the intermediate, and 10 mL tetrahydrofuran were mixed and reacted in an ice-water bath for 2 h, then at room temperature for 8 h, followed by rotary evaporation to obtain a rigid organic compound;

[0072] A2: 1.8g of rigid organic compound, 0.01g of azobisisobutyronitrile, 1mg of activated 2-cyanopropyl-2-ylbenzodisulfide prepared in Example 1, and 15mL of chlorobenzene were mixed and added to a reaction vessel. The mixture was heated to 80°C under a nitrogen atmosphere and stirred for 6h. Tetrahydrofuran was added, centrifuged, and vacuum dried to obtain a rigid polymer.

[0073] A3: 23.6g of epoxy resin (Dow DER661), 4.6g of modified barium titanate prepared in Example 2, 0.3g of rigid polymer, 43g of anhydrous ethanol, 0.5g of BYK-9010, 4.3g of methyltetrahydrophthalic anhydride, and 0.4g of 2-ethyl-4-methylimidazolium were blended, dried in a vacuum oven to remove air bubbles, and then added to a mold to obtain a dielectric material by hot pressing.

[0074] Performance testing

[0075] 1. Withstand Voltage: According to GB / T 2693-2001 "Fixed Capacitors for Electronic Equipment", Examples 4-6 and Comparative Examples 1-2 were placed in the test circuit. The circuit contained a single-pole three-throw switch, with three stationary contacts that could charge, discharge, and short-circuit the capacitor, respectively. The voltage was adjusted to the required test voltage, and the switch was placed on the stationary contact that charged the capacitor to charge the sample. After reaching the test voltage, the switch was held in this position for a specified time. Then, the switch was moved to the stationary contact that discharged the capacitor to discharge the sample. When the voltmeter reading dropped to zero, the switch was moved to the stationary contact that short-circuited the capacitor and the sample was removed. The above operation was repeated several times, and the presence of breakdown and arcing phenomena at the three stationary contacts was observed. The results are shown in Table 1.

[0076] 2. Heat resistance: The high-voltage solid capacitor was placed in an environment of 85℃ for leakage current measurement. According to GB / T 2693-2001 "Fixed capacitors for electronic equipment", the capacitor was connected in series with a 1kΩ protective resistor and then connected to a regulated power supply for leakage current measurement. Before the measurement, the sample was fully discharged. The results are shown in Table 1.

[0077] Table 1. Performance test data statistics for Examples 4-6 and Comparative Examples 1-2

[0078]

[0079] As shown in Table 1, Examples 4-6 exhibited excellent withstand voltage performance and low leakage current at 85°C. Comparative Example 1, due to the lack of barium titanate encapsulation treatment, had the worst withstand voltage performance among all Examples and Comparative Examples, with a slightly increased leakage current compared to the Examples. Comparative Example 2, due to the lack of chemical bonding between barium titanate and rigid polymer compounds, had the largest leakage current among all Examples and Comparative Examples.

[0080] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0081] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A high voltage solid state capacitor characterized by, It includes a core package and an outer shell, wherein the core package includes an anode foil, a positive terminal, a cathode foil, a negative terminal, a dielectric material, a solid electrolyte, and electrolytic paper; The anode foil is an etched aluminum foil; The cathode foil is aluminum foil; The dielectric material is a rigid polymer compound coated with barium titanate powder and epoxy resin. The method for preparing the dielectric material includes the following steps: A1: Mix vinyl terephthalic acid, dichloromethane, oxaloyl chloride, and N,N-dimethylformamide and react for 4-8 h, then rotary evaporate to obtain an intermediate; mix the intermediate, p-aminophenol, and tetrahydrofuran, react in an ice-water bath for 1-3 h, then at room temperature for 6-10 h, and rotary evaporate to obtain a rigid organic compound. A2: Surface-aminated barium titanate powder, activated 2-cyanopropyl-2-ylbenzodisulfide, and tetrahydrofuran are mixed and stirred for 10-14 h, centrifuged, and vacuum dried to obtain modified barium titanate. Modified barium titanate, rigid structure organic compound, azobisisobutyronitrile, and chlorobenzene are mixed and added to a reaction vessel. The mixture is heated to 70-90℃ under a nitrogen atmosphere and stirred and kept at the temperature for 4-8 h. Tetrahydrofuran is added, centrifuged, and vacuum dried to obtain coated barium titanate. A3: Epoxy resin, coated barium titanate, anhydrous ethanol, dispersant, curing agent, and accelerator are mixed and dispersed for 24 hours. The mixture is then dried in a vacuum oven to remove air bubbles and added to a mold to obtain a dielectric material by hot pressing.

2. A high voltage solid state capacitor as defined in claim 1, wherein In A1, the weight ratio of vinyl terephthalic acid to oxaloyl chloride is 6-8:9-10; the weight ratio of intermediate to p-aminophenol is 5:5-6.

3. The high voltage solid state capacitor of claim 1, wherein, In A2, the weight ratio of surface-aminated barium titanate powder and activated 2-cyanopropyl-2-benzodisulfide is 5:1.5-3, and the weight ratio of modified barium titanate, rigid-structure organic compound, and azobisisobutyronitrile is 5:1.5-2:0.

01.

4. The high voltage solid state capacitor of claim 1, wherein, The weight ratio of epoxy resin, coated barium titanate, anhydrous ethanol, dispersant, curing agent, and accelerator in A3 is 80-85:15-20:150:0.5-3:12-18:1-2. The dispersant is a phosphate ester dispersant; The curing agent is phthalic anhydride curing agent; The accelerator is 2-ethyl-4-methylimidazole.

5. A high voltage solid state capacitor as defined in claim 1, wherein The method for preparing the activated 2-cyanopropyl-2-ylbenzodisulfide includes the following steps: 2-Cyanopropyl-2-ylbenzodisulfide, 2-mercaptothiazoline, N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, and dichloromethane were added to a reaction flask and mixed. The mixture was stirred for 10-15 hours, filtered, and rotary evaporated to obtain activated 2-cyanopropyl-2-ylbenzodisulfide. The weight ratio of 2-cyanopropyl-2-ylbenzodisulfide, 2-mercaptothiazoline, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 8:6:3.5-4:0.1-0.

15.

6. A high-voltage solid-state capacitor according to claim 1, characterized in that, The preparation method of surface-aminated barium titanate powder includes the following steps: Add barium titanate powder and hydrogen peroxide solution to a reaction flask, disperse by ultrasonication, heat under reflux and stir for 4-8 hours, centrifuge, wash with deionized water, and dry to obtain barium titanate powder with surface hydroxylation. Surface-hydroxylated barium titanate powder, aminosilane coupling agent, and ethanol aqueous solution are added to a reaction vessel, stirred and dispersed, and dried to obtain surface-aminolated barium titanate powder. The concentration of hydrogen peroxide solution is 27-32 wt%, and the addition ratio of barium titanate powder to hydrogen peroxide is 5-15 g: 100 mL; The concentration of anhydrous ethanol in the aqueous ethanol solution is 87-90 vol; the addition ratio of surface-hydroxylated barium titanate powder, aminosilane coupling agent, and aqueous ethanol solution is 5 g: 0.5-2 g: 100 mL.

7. The high voltage solid state capacitor of claim 1, wherein, The method for preparing the etched aluminum foil includes the following steps: Aluminum foil is cleaned with anhydrous ethanol, then immersed in an etching solution at a controlled temperature of 50-70℃ for 2-5 minutes. After washing with deionized water and drying, etched aluminum foil is obtained. The etching solution contains the following components by weight: 5-15 parts concentrated hydrochloric acid, 2-8 parts concentrated sulfuric acid, 1-5 parts ammonium chloride, and 72-92 parts deionized water, wherein the concentration of concentrated hydrochloric acid is 36-38 wt% and the concentration of concentrated sulfuric acid is 95-98 wt%.

8. The method of claim 1-7, wherein the method further comprises, Includes the following steps: S1: Cut each component inside the core package into the specified shape and size, then connect the anode foil to the positive terminal and the cathode foil to the negative terminal, and then assemble them in the order of anode foil, positive terminal, dielectric material, electrolytic paper, negative terminal and cathode foil to obtain the core package semi-finished product; S2: Immerse in an immersion solution containing conductive polymer monomers, heat to cure, and obtain a core package; S3: The core is encapsulated in an aluminum casing, and the positive and negative terminals are led out of the aluminum casing. The casing is then vacuum sealed to obtain a high-voltage solid-state capacitor.

9. The method of claim 8, wherein the high voltage solid state capacitor is prepared by the steps of: The preparation method of the impregnation solution containing the conductive polymer monomer includes the following steps: mixing 5-8 parts of sodium poly(p-styrene sulfonate) with 85-90 parts of deionized water, adding 1-2 parts of 3,4-ethylenedioxythiophene, adjusting the pH to 2-3, adding 2-3 parts of ammonium persulfate and 0.4-1 parts of ferric sulfate, and stirring to disperse evenly to obtain the impregnation solution containing the conductive polymer monomer.

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