Solid-liquid mixed aluminum electrolytic capacitor suitable for low pressure environment

Abstract

The application discloses a solid-liquid mixed aluminum electrolytic capacitor suitable for a low-pressure environment and relates to the technical field of capacitors.The application comprises a core package, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), an electrolyte, a rubber plug and an aluminum shell.The core package is wound by a positive foil, a carbon foil, a guide needle and electrolytic paper and has a cylindrical winding structure.The electrolyte is obtained by mixing ethylene glycol, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, ethyl trifluoroacetate, fluorinated ethylene carbonate, cyclic carbonate and nano silicon dioxide.The electrolyte prepared from ethyl trifluoroacetate and other components effectively improves the low-voltage resistance of the electrolytic capacitor.The introduction of the high-hardness rubber plug and other components further improves the low-temperature and low-voltage resistance.Therefore, the application has a wider application prospect.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and more specifically to a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments. Background Technology

[0002] Solid-liquid hybrid aluminum electrolytic capacitors mainly consist of a core, electrolyte, rubber stopper, and aluminum shell. The core typically comprises a cylindrical wound structure consisting of positive and negative electrode foils, conductive pins, and electrolytic paper. The electrolyte inside the core is generally a conductive polymer and liquid electrolyte. As important electronic devices for energy storage, filtering, smoothing, and rectification, aluminum electrolytic capacitors are used not only in standard atmospheric pressure environments but also in vacuum or low-pressure and low-temperature environments, such as satellites (500 km altitude), aircraft (10,000 m altitude), and high-altitude regions (5000 m altitude).

[0003] However, in practical applications, solid-liquid hybrid aluminum electrolytic capacitors still suffer from several problems. These include the electrolyte's tendency to volatilize, decompose, and become inactive under low pressure; the conductive polymer's tendency to peel and shrink under low temperature and pressure; and the rubber stopper's tendency to deform under low pressure, causing internal structural damage. Therefore, the low-temperature and low-pressure resistance of the electrolyte, conductive polymer, and rubber stopper in existing solid-liquid hybrid aluminum electrolytic capacitors still needs improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments, solving the following technical problems:

[0005] Existing solid-liquid hybrid aluminum electrolytic capacitors still suffer from poor resistance to low temperatures and low voltages in terms of electrolyte, conductive polymer, and rubber stoppers.

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

[0007] A solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments includes a core, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid), electrolyte, rubber stopper, and aluminum shell.

[0008] The core package is formed by winding positive electrode foil, carbon foil, conductive needles, and electrolytic paper, and has a cylindrical winding structure.

[0009] The electrolyte is prepared by mixing ethylene glycol, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, ethyl trifluoroacetate, fluoroethylene carbonate, cyclic carbonate, and nano silica.

[0010] Preferably, the particle size of the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) is 10-15 nm.

[0011] Preferably, the mass ratio of ethylene glycol, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, ethyl trifluoroacetate, fluoroethylene carbonate, cyclic carbonate, and nano silica is 30-80:0.5-15:0.3-12:2-10:2-15:0.1-25:0.1-10.

[0012] Preferably, the carbonate compound is any one or more of propylene carbonate, ethylene carbonate, and fluoroethylene carbonate.

[0013] Preferably, the rubber stopper is prepared by the following method:

[0014] A1: Mix perfluoropolyether with nano-silica and sonicate at 50-70℃ under nitrogen atmosphere for 30-60 min to obtain modified silica;

[0015] A2: Graphene oxide and molybdenum disulfide were added to N,N-dimethylformamide and subjected to ultrasonic treatment for 2-4 hours. After vacuum drying, composite nanosheets were obtained.

[0016] A3: Mix EPDM rubber and hydrogenated nitrile rubber and pass through a thin tube 5-10 times at 60-80℃. Then add carbon black, magnesium hydroxide, zinc oxide and stearic acid in sequence and mix at 60-80℃ for 10-15 minutes. Then add modified silica and composite nanosheets and mix at a roller temperature of 50-70℃ for 15-20 minutes. Finally add sulfur and accelerator CBS and pass through a thin tube 3-5 times at 50-70℃ for 5-10 minutes to obtain the compound.

[0017] A4: Inject the compounded rubber into the mold and place it at 20-35℃ for 12-24 hours. Then vulcanize it, demold it, and immerse it in an aqueous solution of ammonium perfluorooctanoate. After treatment at 60-80℃ for 1-2 hours, wash it with water and dry it to obtain the rubber stopper.

[0018] Preferably, the mass ratio of the perfluoropolyether to nano-silica in A1 is 10-20:10.

[0019] Preferably, the mass ratio of N,N-dimethylformamide, graphene oxide, and molybdenum disulfide in A2 is 100-200:1-3:1.

[0020] Preferably, the mass ratio of EPDM rubber, hydrogenated nitrile rubber, carbon black, magnesium hydroxide, zinc oxide, stearic acid, modified silica, composite nanosheets, sulfur, and accelerator CBS in A3 is 50-70:30-50:10-20:5-10:3-5:1-3:5-15:2-8:1-2:0.5-1.5.

[0021] Preferably, the vulcanization treatment described in A4 is as follows: first vulcanize at 160-180℃ and 10-15MPa for 10-20 minutes, then cool to room temperature and treat at 80-100℃ and 10-15Pa vacuum for 2-4 hours;

[0022] The mass fraction of the perfluorooctanoic acid ammonium aqueous solution described in A4 is 5%-10%.

[0023] Preferably, the method for preparing the solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows:

[0024] The core is filled with conductive polymer and electrolyte, and the core's guide pin is passed through the hole of the rubber stopper. The rubber stopper and core are then assembled together and installed in an aluminum shell. The aluminum shell is then sealed and waisted under an absolute pressure of 51-81 kPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 20-50 kPa.

[0025] The beneficial effects of this invention are:

[0026] This invention provides a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments. The invention effectively improves the operating temperature range of the electrolyte in the solid-liquid hybrid aluminum electrolytic capacitor under low-pressure environments through the following methods, also improves the dimensional stability of the rubber stopper under strong pressure differentials, and reduces the negative impact of conductive polymer shrinkage at low temperatures.

[0027] (1) The 1-ethyl-3-methylimidazolium bis-(trifluoromethanesulfonyl)imide salt added to the electrolyte of this invention has an extremely low vapor pressure, which can significantly reduce the overall volatility of the electrolyte; under low pressure, it can inhibit the escape of solvent molecules through intermolecular interactions; it has good antioxidant properties, which can inhibit the decomposition reaction of the electrolyte at high temperature or low pressure; its wide liquid phase temperature range helps to maintain the fluidity of the electrolyte at low temperature and reduce the ion conduction resistance caused by increased viscosity. The alkyl chain of N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt is longer and the intermolecular forces are stronger. Its addition can further reduce the solvent escape rate; it can also form a stable ionic liquid interface layer on the electrode surface, inhibit the side reactions between the electrolyte and the electrode, and reduce decomposition products; its lower melting point can lower the freezing point of the electrolyte and improve the ion conduction ability at low temperature. The introduction of fluorine atoms in ethyl trifluoroacetate weakens the intermolecular forces and lowers the freezing point, which can prevent the electrolyte from solidifying at low temperature and maintain liquid fluidity. Ethyl trifluoroacetate has a high boiling point, and the fluorine atoms enhance the stability of the carbon-fluorine bond, reducing the tendency for vaporization at low pressures. It decomposes on the negative electrode surface to form a fluorine-containing film, preventing further electrolyte decomposition and extending its service life. Fluorinated ethylene carbonate has strong electronegativity of fluorine atoms, which enhances intermolecular interactions, lowers the solvent vapor pressure, and reduces the risk of vaporization at low pressures. Its high carbon-fluorine bond energy makes it less prone to breakage, improving the thermal stability of the electrolyte and reducing decomposition. Its low viscosity also improves ion migration rate, maintaining ion conductivity even at low pressures. Propylene carbonate has a high dielectric constant, which facilitates solute dissociation, increases ion concentration, and enhances the conductivity of the electrolyte. Its low melting point lowers the freezing point of the electrolyte, maintaining ion conductivity at low temperatures and improving electrochemical activity at low temperatures. Nano-sized silica particles form a physical barrier, hindering the diffusion and escape of solvent molecules and reducing volatility. Their high specific surface area adsorbs heat in the electrolyte, slowing down decomposition reactions caused by temperature fluctuations, improving ion mobility at low temperatures, and enhancing low-temperature conductivity.

[0028] (2) The low surface energy barrier formed by the perfluoropolyether molecular chains on the surface of the modified silica in this invention can inhibit the dissolution and diffusion of gas molecules in the rubber; the silanol groups on the surface of silica will form hydrogen bonds or covalent bonds with the rubber molecular chains, enhancing the intermolecular forces and significantly increasing the hardness of the rubber; thus greatly reducing the deformation rate of the rubber under strong pressure difference and maintaining the sealing performance. The composite nanosheets form a continuous physical barrier by the layered stacking of graphene oxide and molybdenum disulfide, requiring the gas to diffuse along a tortuous path, effectively reducing the gas permeability of the rubber; the combination of the oxygen-containing groups of graphene oxide and the interlayer slip characteristics of molybdenum disulfide enhances the interfacial adhesion and inhibits crack propagation, improving the tear strength of the rubber stopper; the low interlayer friction coefficient of molybdenum disulfide acts as a "ball bearing" in high-hardness rubber, alleviating stress concentration. The wide temperature range stability of perfluoropolyether and the thermal conductivity of graphene oxide work synergistically to reduce the volume change rate of the rubber stopper under temperature fluctuations, avoiding sealing failure caused by thermal expansion and contraction.

[0029] (3) The poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) particles of the specific size of this invention have extremely high specific surface area, which significantly increases the contact area with the electrolyte and electrode materials. They can penetrate deep into the tunnel-like micropores of aluminum foil and adhere to the inner wall surface of the micropores to form a film structure. In low-temperature environments, the gaps between particles can be reduced, lowering the risk of interfacial separation caused by thermal expansion and contraction, thereby weakening the tendency of particles to peel off from the electrode surface. The nano-sized particles of this invention are more uniformly distributed in the core package, filling the pores of the electrode material and forming a more continuous ion conduction network. When the viscosity of the electrolyte increases at low temperatures, these uniformly distributed nanoparticles can shorten the ion migration distance and alleviate the capacity decay caused by increased transport resistance. In addition, the sulfonic acid groups in its molecular chain can form hydrogen bonds with the polar solvent in the electrolyte, enhancing the compatibility between the particles and the electrolyte and reducing phase separation at low temperatures. Even if slight shrinkage occurs, the conductive contact between particles can still be maintained, avoiding capacity decrease caused by obstructed electron transport. The surface of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) particles can adsorb polar components in the electrolyte, forming a more stable interfacial layer. At low temperatures, as electrolyte viscosity increases, this interfacial layer acts as an "ion channel," maintaining ion transport between the particles and the electrode and reducing capacity decay due to insufficient wetting. The presence of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) particles lowers the freezing point of the electrolyte, reducing the likelihood of electrolyte crystallization at low temperatures, thereby preventing particle peeling or electrode structure damage caused by crystal volume expansion.

[0030] Therefore, the electrolyte, conductive polymer, and rubber stopper in the solid-liquid hybrid aluminum electrolytic capacitor prepared by this invention have excellent resistance to low temperature and low pressure, as well as a wider range of application prospects. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the following information pertains to some of the raw materials used in the following embodiments and comparative examples of this invention:

[0033] The perfluoropolyether was purchased from Shanghai Yuanye Biotechnology Co., Ltd., item number: Y41833; the nano silica was purchased from Zhejiang Manli Nanotechnology Co., Ltd., model: ML-SiO2-N20; the EPDM rubber was purchased from Dongguan Nabaichuan Plastics Co., Ltd., item number: 3720P; the hydrogenated nitrile butadiene rubber was purchased from Shanghai Koraman Reagent Co., Ltd., item number: 201028115718; and the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) was purchased from Shanghai Mairui Biochemical Technology Co., Ltd., item number: M39259.

[0034] Example 1: A method for preparing a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows:

[0035] S1: Add 0.5g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.3g of N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, 2g of ethyl trifluoroacetate, 2g of fluoroethylene carbonate, 0.1g of propylene carbonate, and 0.1g of nano-silica to 30g of ethylene glycol and sonicate for 10min to obtain the electrolyte;

[0036] S2: Mix 10g of perfluoropolyether with 10g of nano-silica and sonicate at 50℃ under nitrogen atmosphere for 30min to obtain modified silica;

[0037] S3: Add 1g of graphene oxide and 1g of molybdenum disulfide to 100g of N,N-dimethylformamide and sonicate for 2 hours, then vacuum dry at 60℃ to obtain composite nanosheets.

[0038] S4: Mix 50g of EPDM rubber and 30g of hydrogenated nitrile butadiene rubber and pass through a thin tube 5 times at 60℃. Then add 10g of carbon black, 5g of magnesium hydroxide, 3g of zinc oxide and 1g of stearic acid in sequence and mix at 60℃ for 10min. Then add 5g of modified silica and 2g of composite nanosheets and mix at a roller temperature of 50℃ for 15min. Finally add 1g of sulfur and 0.5g of accelerator CBS and pass through a thin tube 3 times at 50℃ and mix for 5min to obtain the compound.

[0039] S5: The compound rubber is injected into the mold and placed at 20°C for 12 hours. Then it is vulcanized at 160°C and 10MPa for 10 minutes. After cooling to room temperature, it is treated at 80°C and 10Pa vacuum for 2 hours. Then it is demolded and immersed in a 5% perfluorooctanoic acid ammonium aqueous solution. After treatment at 60°C for 1 hour, it is washed with water and dried to obtain a rubber stopper.

[0040] S6: The positive electrode foil, carbon foil, conductive needle, and electrolytic paper are rolled into a cylindrical wound core package. Then, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) with a particle size of 10-15nm and electrolyte are filled into the core package. The conductive needle of the core package is passed through the hole of the rubber stopper. The rubber stopper and the core package are then assembled together and installed into an aluminum shell. The aluminum shell is then sealed and waisted under an absolute pressure of 51KPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 20KPa.

[0041] Example 2: A method for preparing a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows:

[0042] S1: Add 7.5g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 6g of N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, 6g of ethyl trifluoroacetate, 12.5g of fluoroethylene carbonate, 12.5g of ethylene carbonate, and 5g of nano-silica to 55g of ethylene glycol and sonicate for 20min to obtain the electrolyte;

[0043] S2: Mix 15g of perfluoropolyether with 10g of nano-silica and sonicate at 60℃ under nitrogen atmosphere for 45min to obtain modified silica;

[0044] S3: Add 2g of graphene oxide and 1g of molybdenum disulfide to 150g of N,N-dimethylformamide and sonicate for 3h, then vacuum dry at 70℃ to obtain composite nanosheets.

[0045] S4: Mix 60g of EPDM rubber and 40g of hydrogenated nitrile butadiene rubber and pass through a thin tube 8 times at 70℃. Then add 15g of carbon black, 7.5g of magnesium hydroxide, 4g of zinc oxide, and 2g of stearic acid in sequence and mix at 70℃ for 12min. Then add 10g of modified silica and 5g of composite nanosheets and mix at a roller temperature of 60℃ for 18min. Finally, add 1.5g of sulfur and 1g of accelerator CBS and pass through a thin tube 4 times at 60℃ for 7.5min to obtain the compound.

[0046] S5: The compounded rubber is injected into the mold and placed at 30°C for 18 hours. Then it is vulcanized at 170°C and 13MPa for 15 minutes. After cooling to room temperature, it is treated at 90°C and 13Pa vacuum for 3 hours. Then it is demolded and immersed in an 8% perfluorooctanoic acid ammonium aqueous solution. After treatment at 70°C for 1.5 hours, it is washed with water and dried to obtain the rubber stopper.

[0047] S6: The positive electrode foil, carbon foil, conductive needle, and electrolytic paper are rolled into a cylindrical wound core package. Then, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) with a particle size of 10-15nm and electrolyte are filled into the core package. The conductive needle of the core package is passed through the hole of the rubber stopper. The rubber stopper and the core package are then assembled together and installed into an aluminum shell. The aluminum shell is then sealed and waisted under an absolute pressure of 66KPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 35KPa.

[0048] Example 3: A method for preparing a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows:

[0049] S1: Add 15g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 12g of N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, 10g of ethyl trifluoroacetate, 15g of fluoroethylene carbonate, 12.5g of propylene carbonate, 12.5g of ethylene carbonate, and 10g of nano-silica to 80g of ethylene glycol and sonicate for 30min to obtain the electrolyte;

[0050] S2: Mix 20g of perfluoropolyether with 10g of nano-silica and sonicate at 70℃ under nitrogen atmosphere for 60min to obtain modified silica;

[0051] S3: Add 3g of graphene oxide and 1g of molybdenum disulfide to 200g of N,N-dimethylformamide and sonicate for 4h, then vacuum dry at 80℃ to obtain composite nanosheets.

[0052] S4: Mix 70g of EPDM rubber and 50g of hydrogenated nitrile butadiene rubber and pass through a thin tube 10 times at 80℃. Then add 20g of carbon black, 10g of magnesium hydroxide, 5g of zinc oxide, and 3g of stearic acid in sequence and mix at 80℃ for 15min. Then add 15g of modified silica and 8g of composite nanosheets and mix at 70℃ for 20min. Finally, add 2g of sulfur and 1.5g of accelerator CBS and pass through a thin tube 5 times at 70℃ and mix for 10min to obtain the compound.

[0053] S5: The compounded rubber is injected into the mold and placed at 35°C for 24 hours. Then it is vulcanized at 180°C and 15MPa for 20 minutes. After cooling to room temperature, it is treated at 100°C and 15Pa vacuum for 4 hours. Then it is demolded and immersed in a 10% perfluorooctanoic acid ammonium aqueous solution. After treatment at 80°C for 2 hours, it is washed with water and dried to obtain a rubber stopper.

[0054] S6: The positive electrode foil, carbon foil, conductive needle, and electrolytic paper are rolled into a cylindrical wound core package. Then, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) with a particle size of 10-15nm and electrolyte are filled into the core package. The conductive needle of the core package is passed through the hole of the rubber stopper. The rubber stopper and the core package are then assembled together and installed into an aluminum shell. The aluminum shell is then sealed and waisted under an absolute pressure of 81KPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 50KPa.

[0055] Comparative Example 1:

[0056] Compared with Example 1, this comparative example only replaces "1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt" added during the preparation of S1 with "N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a solid-liquid mixed aluminum electrolytic capacitor is obtained.

[0057] Comparative Example 2:

[0058] Compared with Example 1, this comparative example only replaces "N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt" added in the preparation process of S1 with "1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a solid-liquid mixed aluminum electrolytic capacitor is obtained.

[0059] Comparative Example 3:

[0060] Compared with Example 1, this comparative example only did not add "ethyl trifluoroacetate" in the preparation process of S1. All other steps and parameters were the same, and will not be repeated here. The final product was a solid-liquid hybrid aluminum electrolytic capacitor.

[0061] Comparative Example 4:

[0062] Compared with Example 1, this comparative example only did not add "fluoroethylene carbonate" in the preparation process of S1. All other steps and parameters were the same, and will not be repeated here. The final product was a solid-liquid hybrid aluminum electrolytic capacitor.

[0063] Comparative Example 5:

[0064] Compared with Example 1, this comparative example only did not add "nano-silica" in the preparation process of S1. All other steps and parameters were the same, and will not be repeated here. The final product was a solid-liquid hybrid aluminum electrolytic capacitor.

[0065] Comparative Example 6:

[0066] Compared with Example 1, this comparative example only did not add "composite nanosheets" in the preparation process of S4. All other steps and parameters were the same, and will not be repeated here. The final product was a solid-liquid hybrid aluminum electrolytic capacitor.

[0067] Comparative Example 7:

[0068] Compared with Example 1, this comparative example only did not add "modified nano-silica" in the preparation process of S4. All other steps and parameters were the same, and will not be repeated here. The final product was a solid-liquid hybrid aluminum electrolytic capacitor.

[0069] Performance testing:

[0070] Determination of boiling point under low pressure:

[0071] The electrolytes prepared in Examples 1-3 and Comparative Examples 1-7 of this invention were used to determine their boiling points (°C) at 30 kPa. The test results are shown in Table 1.

[0072] Determination of freezing point under low pressure:

[0073] The electrolytes prepared in Examples 1-3 and Comparative Examples 1-7 of this invention were used to determine their freezing point (°C) at 30 kPa. The test results are shown in Table 1.

[0074] Hardness determination:

[0075] Referring to GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test", the hardness (Shore A) of the rubber plugs prepared in Examples 1-3 and Comparative Examples 1-7 of this invention was determined, and the test results are shown in Table 1.

[0076] Determination of deformation rate:

[0077] The rubber stoppers prepared in Examples 1-3 and Comparative Examples 1-7 of this invention were used to measure their deformation rate (%) under the condition that the internal pressure is higher than the external pressure and the pressure difference is 30 kPa. The test results are shown in Table 1.

[0078] Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-7

[0079]

[0080] Data Analysis:

[0081] As can be seen from Table 1, the electrolyte in the solid-liquid hybrid aluminum electrolytic capacitor prepared in the embodiments of the present invention, which is suitable for low-pressure environments, has a high boiling point and a low freezing point under low pressure; at the same time, the rubber stopper also has excellent hardness and dimensional stability.

[0082] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments, characterized in that, Includes core package, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), electrolyte, rubber stopper, and aluminum shell; The core package is formed by winding positive electrode foil, carbon foil, conductive needles, and electrolytic paper, and has a cylindrical winding structure. The electrolyte is prepared by mixing ethylene glycol, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, ethyl trifluoroacetate, fluoroethylene carbonate, cyclic carbonate, and nano silica. The particle size of the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) is 10-15 nm. The method for preparing the rubber stopper is as follows: A1: Mix perfluoropolyether with nano-silica and sonicate at 50-70℃ under nitrogen atmosphere for 30-60 min to obtain modified silica; A2: Graphene oxide and molybdenum disulfide were added to N,N-dimethylformamide and subjected to ultrasonic treatment for 2-4 hours. After vacuum drying, composite nanosheets were obtained. A3: Mix EPDM rubber and hydrogenated nitrile rubber and pass through a thin tube 5-10 times at 60-80℃. Then add carbon black, magnesium hydroxide, zinc oxide and stearic acid in sequence and mix at 60-80℃ for 10-15 minutes. Then add modified silica and composite nanosheets and mix at a roller temperature of 50-70℃ for 15-20 minutes. Finally add sulfur and accelerator CBS and pass through a thin tube 3-5 times at 50-70℃ for 5-10 minutes to obtain the compound. A4: Inject the compounded rubber into the mold and place it at 20-35℃ for 12-24 hours. Then vulcanize it, demold it, and immerse it in an aqueous solution of ammonium perfluorooctanoate. After treatment at 60-80℃ for 1-2 hours, wash it with water and dry it to obtain the rubber stopper.

2. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The mass ratio of ethylene glycol, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, ethyl trifluoroacetate, fluoroethylene carbonate, cyclic carbonate, and nano silica is 30-80:0.5-15:0.3-12:2-10:2-15:0.1-25:0.1-10.

3. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The cyclic carbonate is any one or more of propylene carbonate and ethylene carbonate.

4. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The mass ratio of perfluoropolyether to nano-silica in A1 is 10-20:

10.

5. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The mass ratio of N,N-dimethylformamide, graphene oxide, and molybdenum disulfide in A2 is 100-200:1-3:

1.

6. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The mass ratio of EPDM rubber, hydrogenated nitrile rubber, carbon black, magnesium hydroxide, zinc oxide, stearic acid, modified silica, composite nanosheets, sulfur, and accelerator CBS described in A3 is 50-70:30-50:10-20:5-10:3-5:1-3:5-15:2-8:1-2:0.5-1.

5.

7. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The vulcanization process described in A4 is as follows: first vulcanize at 160-180℃ and 10-15MPa for 10-20 minutes, then cool to room temperature and treat at 80-100℃ and vacuum degree of 10-15Pa for 2-4 hours. The mass fraction of the perfluorooctanoic acid ammonium aqueous solution described in A4 is 5%-10%.

8. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that, The method for preparing the solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows: The core is filled with conductive polymer and electrolyte, and the core's guide pin is passed through the hole of the rubber stopper. The rubber stopper and core are then assembled together and installed in an aluminum shell. The aluminum shell is then sealed and waisted under an absolute pressure of 51-81 kPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 20-50 kPa.

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