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

Abstract

The invention discloses a solid-liquid mixed aluminum electrolytic capacitor suitable for a low-pressure environment, and relates to the technical field of capacitors. The lithium ion battery comprises a core package, poly (3, 4-ethylenedioxythiophene)-poly (styrenesulfonic acid), electrolyte, a rubber plug and an aluminum shell, the core package is formed by winding a positive electrode foil, a carbon foil, a guide pin and electrolytic paper and is of a cylindrical winding structure; the electrolyte is prepared by mixing ethylene glycol, 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonyl) imine salt, N-butyl-N-methylpyrrolidine bis (trifluoromethanesulfonyl) imine salt, ethyl trifluoroacetate, fluoroethylene carbonate, cyclic carbonate and nano silicon dioxide. The preparation method comprises the following steps: mixing the ethylene glycol, the 1-ethyl-3-methylimidazole bis (trifluoromethanesulfonyl) imine salt, the N-butyl-N-methylpyrrolidine bis (trifluoromethanesulfonyl) imine salt with the ethyl trifluoroacetate; the electrolyte prepared from the components such as the ethyl trifluoroacetate effectively improves the low-voltage resistance of the electrolytic capacitor; the introduction of the components such as the high-hardness rubber plug further improves the low-temperature and low-pressure resistance. Therefore, the method has a wider application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments. Background Art

[0002] Solid-liquid hybrid aluminum electrolytic capacitors primarily consist of a core pack, electrolyte, rubber plug, and aluminum shell. The core pack typically consists of a cylindrically wound structure consisting of positive and negative electrode foils, guide pins, and electrolytic paper. The electrolyte inside the core pack is typically a conductive polymer and electrolyte solution. Aluminum electrolytic capacitors, as important electronic components for energy storage, filtering, smoothing, and rectification, can be used in vacuum or low-pressure, low-temperature environments, in addition to standard pressure environments. These applications include satellites (500 kilometers above sea level), aircraft (10,000 meters above sea level), and plateau regions (5,000 meters above sea level).

[0003] However, in practical applications, solid-liquid hybrid aluminum electrolytic capacitors still face challenges: the electrolyte is prone to volatilization, gasification, decomposition, and inactivity at low pressures; the conductive polymer is prone to peeling and shrinking at low temperatures and low pressures; and the rubber stopper is prone to deformation in low-pressure environments, causing damage to the internal structure. 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 to be improved. Summary of the Invention

[0004] The purpose of the present invention is to provide a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments to solve the following technical problems: Existing solid-liquid hybrid aluminum electrolytic capacitors still have the problem that the electrolyte, conductive polymer and rubber plug have relatively poor low-temperature and low-voltage resistance.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments, comprising a core package, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), an electrolyte, a rubber plug, and an aluminum shell; The core package is formed by winding the positive electrode foil, carbon foil, guide pins and electrolytic paper into a cylindrical winding structure; The electrolyte is obtained 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-silicon dioxide.

[0006] Preferably, the particle size of the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) is 10-15 nm.

[0007] Preferably, the mass ratio of ethylene glycol, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidino 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.

[0008] Preferably, the carbonate compound is any one or more of propylene carbonate, ethylene carbonate, and fluoroethylene carbonate.

[0009] Preferably, the preparation method of the rubber stopper is as follows: A1: Perfluoropolyether and nano-silica were mixed and ultrasonically treated at 50-70°C under nitrogen atmosphere for 30-60 minutes to obtain modified silica; A2: Add graphene oxide and molybdenum disulfide to N,N-dimethylformamide and perform ultrasonic treatment for 2-4 hours, and then vacuum dry to obtain composite nanosheets; A3: EPDM rubber and hydrogenated nitrile rubber are mixed and thinned for 5-10 times at 60-80°C. Then, carbon black, magnesium hydroxide, zinc oxide, and stearic acid are added in sequence and mixed at 60-80°C for 10-15 minutes. Then, modified silica and composite nanosheets are added and mixed at a roller temperature of 50-70°C for 15-20 minutes. Finally, sulfur and accelerator CBS are added and thinned for 3-5 times at 50-70°C and mixed for 5-10 minutes to obtain a rubber compound. A4: The rubber mix is ​​injected into a mold and placed at 20-35°C for 12-24 hours, followed by vulcanization treatment. The mold is then demoulded and immersed in an aqueous solution of ammonium perfluorooctanoate. The mixture is treated at 60-80°C for 1-2 hours, washed with water, and dried to obtain a rubber stopper.

[0010] Preferably, the mass ratio of the perfluoropolyether to the nano-silicon dioxide in A1 is 10-20:10.

[0011] Preferably, the mass ratio of N,N-dimethylformamide, graphene oxide and molybdenum disulfide in A2 is 100-200:1-3:1.

[0012] Preferably, the mass ratio of the 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.

[0013] Preferably, the vulcanization treatment in A4 is: first vulcanizing at 160-180°C and 10-15 MPa for 10-20 min, then cooling to room temperature and treating at 80-100°C and vacuum of 10-15 Pa for 2-4 h; The mass fraction of the ammonium perfluorooctanoate aqueous solution described in A4 is 5%-10%.

[0014] Preferably, the preparation method of the solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environment is: The core package is filled with conductive polymer and electrolyte, and the guide pin of the core package is passed through the hole of the rubber plug. The rubber plug and the core package are assembled together and placed in an aluminum shell. The aluminum shell is then sealed and waisted at 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.

[0015] Beneficial effects of the present invention: The present invention provides a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments. The present 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 method, improves the dimensional stability of the rubber stopper under a strong pressure difference, and reduces the negative impact of the conductive polymer caused by dimensional shrinkage at low temperatures.

[0016] (1) The vapor pressure of 1-ethyl-3-methylimidazolium bis-(trifluoromethanesulfonyl)imide salt added to the electrolyte of the present invention is extremely low, 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 and 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 temperatures and reduce the ion conduction resistance caused by increased viscosity. N-butyl-N-methylpyrrolidine bis-(trifluoromethanesulfonyl)imide salt has a longer alkyl chain and stronger intermolecular forces, and its addition can further reduce the escape rate of the solvent; it can also form a stable ionic liquid interface layer on the electrode surface, inhibiting the side reaction between the electrolyte and the electrode and reducing the decomposition products; its lower melting point can lower the freezing point of the electrolyte and improve the ion conduction ability at low temperatures. 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 temperatures and maintain liquid fluidity. Ethyl trifluoroacetate has a high boiling point, and its fluorine atoms enhance the stability of the carbon-fluorine bond, reducing its tendency to vaporize at low pressures. It decomposes on the negative electrode surface to form a fluorine-containing film, which prevents further decomposition of the electrolyte and extends its service life. The fluorine atoms in fluoroethylene carbonate have strong electronegativity, enhancing intermolecular interactions, reducing the solvent's vapor pressure, and reducing the risk of vaporization at low pressures. Its high carbon-fluorine bond energy is resistant to breakage, improving the electrolyte's thermal stability and reducing decomposition. Its low viscosity also improves ion mobility, maintaining ion conductivity even at low pressures. Propylene carbonate has a high dielectric constant, which facilitates solute dissociation, increases ion concentration, and enhances the electrolyte's conductive activity. Its low melting point lowers the electrolyte's freezing point, maintaining ion conduction at low temperatures and improving electrochemical activity at low temperatures. Nanosilica particles form a physical barrier, hindering the diffusion and escape of solvent molecules and reducing volatility. Their high surface area absorbs heat from the electrolyte, slowing decomposition reactions caused by temperature fluctuations, increasing ion mobility at low temperatures, and improving low-temperature conductivity.

[0017] (2) The low surface energy barrier formed by the perfluoropolyether molecular chains on the surface of the modified silica of the present invention can inhibit the dissolution and diffusion of gas molecules in the rubber; the silanol groups on the surface of the silica will form hydrogen bonds or covalent bonds with the rubber molecular chains, strengthening the intermolecular forces and significantly improving the hardness of the rubber; the deformation rate of the rubber under strong pressure difference is greatly reduced, and the sealing performance is maintained. The composite nanosheet is a layered stack of graphene oxide and molybdenum disulfide to form a continuous physical barrier. The gas needs to diffuse along a tortuous path, which effectively reduces the gas permeability of the rubber; the oxygen-containing groups of graphene oxide are combined with the interlayer slip characteristics of molybdenum disulfide to enhance the interfacial adhesion and inhibit crack propagation, thereby improving the tear strength of the rubber plug; the interlayer friction coefficient of molybdenum disulfide is low, and it plays the role of a "ball bearing" in high-hardness rubber, relieving 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 plug under temperature fluctuations, avoiding sealing failure caused by thermal expansion and contraction.

[0018] (3) The poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) particles of the specific particle size of the present invention have an extremely high specific surface area, and the contact area with the electrolyte and electrode material will be significantly increased. They can penetrate into the tunnel-type micropores of the aluminum foil and adhere to the inner wall surface of the micropore to form a membrane structure; in a low-temperature environment, the gaps between the particles can be reduced, and the risk of interface separation caused by thermal expansion and contraction can be reduced, thereby weakening the tendency of particles to peel off from the electrode surface. The nano-scale particles of the present invention are more evenly distributed in the core package, can fill the pores of the electrode material and form a more continuous ion conduction network. When the viscosity of the electrolyte increases at low temperatures, these evenly distributed nanoparticles can shorten the ion migration distance and alleviate the capacity attenuation caused by increased transmission resistance. In addition, the sulfonic acid groups in its molecular chain can form hydrogen bonds with the polar solvent in the electrolyte, enhance the compatibility of the particles with the electrolyte, and reduce phase separation at low temperatures. Even if slight shrinkage occurs, the conductive contact between the particles can still be maintained, avoiding the capacity drop caused by the obstruction of electron transmission. The surface of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) particles can adsorb polar components in the electrolyte, forming a more stable interfacial layer. When the electrolyte viscosity increases at low temperatures, this interfacial layer acts as an "ion channel," maintaining ion transport between the particles and the electrode, reducing capacity decay due to insufficient wetting. The presence of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) particles lowers the freezing point of the electrolyte, reducing the likelihood of electrolyte crystallization at low temperatures, thereby preventing particle delamination or electrode structural damage caused by crystal volume expansion.

[0019] Therefore, the electrolyte, conductive high polymer and rubber plug in the solid-liquid hybrid aluminum electrolytic capacitor prepared by the present invention have excellent low-temperature and low-voltage resistance, as well as a wider application prospect. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] Unless otherwise specified, some of the raw materials used in the following examples and comparative examples of the present invention are as follows: Perfluoropolyether was purchased from Shanghai Yuanye Biotechnology Co., Ltd., item number: Y41833; nanosilica was purchased from Zhejiang Manli Nanotechnology Co., Ltd., model: ML-SiO2-N20; EPDM rubber was purchased from Dongguan Nabaichuan Plastic Chemical Co., Ltd., item number: 3720P; hydrogenated nitrile rubber was purchased from Shanghai Koraman Reagent Co., Ltd., item number: 201028115718; poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) was purchased from Shanghai Mairui Biochemical Technology Co., Ltd., item number: M39259.

[0022] Example 1: A method for preparing a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows: S1: 0.5 g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 0.3 g of N-butyl-N-methylpyrrolidino bis(trifluoromethanesulfonyl)imide, 2 g of ethyl trifluoroacetate, 2 g of fluoroethylene carbonate, 0.1 g of propylene carbonate, and 0.1 g of nano-silica were added to 30 g of ethylene glycol and ultrasonicated for 10 min to obtain an electrolyte; S2: 10 g of perfluoropolyether and 10 g of nano-silica were mixed and ultrasonically treated at 50 °C under nitrogen atmosphere for 30 min to obtain modified silica; S3: 1 g of graphene oxide and 1 g of molybdenum disulfide were added to 100 g of N,N-dimethylformamide and ultrasonicated for 2 h, followed by vacuum drying at 60 °C to obtain composite nanosheets; S4: 50 g of EPDM rubber and 30 g of hydrogenated nitrile rubber were mixed and thinned for 5 times at 60° C., followed by the addition of 10 g of carbon black, 5 g of magnesium hydroxide, 3 g of zinc oxide, and 1 g of stearic acid, and kneading at 60° C. for 10 min. 5 g of modified silica and 2 g of composite nanosheets were added, and the mixture was kneaded at a roller temperature of 50° C. for 15 min. Finally, 1 g of sulfur and 0.5 g of accelerator CBS were added, and the mixture was thinned for 3 times at 50° C. and kneaded for 5 min to obtain a rubber mixture; S5: The rubber mix was injected into a mold and placed at 20°C for 12 hours, then vulcanized at 160°C and 10 MPa for 10 minutes, cooled to room temperature, and treated at 80°C and 10 Pa in vacuum for 2 hours. The mold was then removed and immersed in a 5% by mass aqueous solution of ammonium perfluorooctanoate, treated at 60°C for 1 hour, washed with water, and dried to obtain a rubber stopper. S6: The positive electrode foil, carbon foil, guide needle, and electrolytic paper are rolled into a core package with a cylindrical winding structure. Then, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) with a particle size of 10-15 nm and electrolyte are filled into the core package, and the guide needle of the core package is passed through the hole of the rubber plug. The rubber plug and the core package are assembled together and installed in an aluminum shell. The aluminum shell is then sealed and waisted at an absolute pressure of 51 kPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 20 kPa.

[0023] Example 2: A method for preparing a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows: S1: 7.5 g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 6 g of N-butyl-N-methylpyrrolidino bis(trifluoromethanesulfonyl)imide, 6 g of ethyl trifluoroacetate, 12.5 g of fluoroethylene carbonate, 12.5 g of ethylene carbonate, and 5 g of nano-silica were added to 55 g of ethylene glycol and ultrasonicated for 20 min to obtain an electrolyte; S2: 15 g of perfluoropolyether and 10 g of nano-silica were mixed and ultrasonically treated at 60 °C under nitrogen atmosphere for 45 min to obtain modified silica; S3: 2 g of graphene oxide and 1 g of molybdenum disulfide were added to 150 g of N,N-dimethylformamide and ultrasonicated for 3 h, followed by vacuum drying at 70 °C to obtain composite nanosheets; S4: 60 g of EPDM rubber and 40 g of hydrogenated nitrile rubber were mixed and thinned 8 times at 70° C., followed by the addition of 15 g of carbon black, 7.5 g of magnesium hydroxide, 4 g of zinc oxide, and 2 g of stearic acid, and kneaded at 70° C. for 12 min. 10 g of modified silica and 5 g of composite nanosheets were then added and kneaded at a roller temperature of 60° C. for 18 min. Finally, 1.5 g of sulfur and 1 g of accelerator CBS were added, and the mixture was thinned 4 times at 60° C. and kneaded for 7.5 min to obtain a rubber compound; S5: The rubber mix was injected into a mold and placed at 30°C for 18 hours, then vulcanized at 170°C and 13 MPa for 15 minutes, cooled to room temperature, and treated at 90°C and 13 Pa in vacuum for 3 hours. The mold was then removed and immersed in an 8% by mass aqueous solution of ammonium perfluorooctanoate, treated at 70°C for 1.5 hours, washed with water, and dried to obtain a rubber stopper. S6: The positive electrode foil, carbon foil, guide needle, and electrolytic paper are rolled into a core package with a cylindrical winding structure. Then, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) with a particle size of 10-15 nm and electrolyte are filled into the core package, and the guide needle of the core package is passed through the hole of the rubber plug. The rubber plug and the core package are assembled together and installed in an aluminum shell. The aluminum shell is then sealed and waisted at an absolute pressure of 66 kPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 35 kPa.

[0024] Example 3: A method for preparing a solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments is as follows: S1: 15 g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 12 g of N-butyl-N-methylpyrrolidino bis(trifluoromethanesulfonyl)imide, 10 g of ethyl trifluoroacetate, 15 g of fluoroethylene carbonate, 12.5 g of propylene carbonate, 12.5 g of ethylene carbonate, and 10 g of nano-silica were added to 80 g of ethylene glycol and ultrasonicated for 30 min to obtain an electrolyte; S2: 20 g of perfluoropolyether and 10 g of nano-silica were mixed and ultrasonically treated at 70 °C under nitrogen atmosphere for 60 min to obtain modified silica; S3: 3 g of graphene oxide and 1 g of molybdenum disulfide were added to 200 g of N,N-dimethylformamide and ultrasonicated for 4 h, followed by vacuum drying at 80 °C to obtain composite nanosheets; S4: 70 g of EPDM rubber and 50 g of hydrogenated nitrile rubber were mixed and thinned 10 times at 80° C., followed by the addition of 20 g of carbon black, 10 g of magnesium hydroxide, 5 g of zinc oxide, and 3 g of stearic acid, and kneading at 80° C. for 15 min. 15 g of modified silica and 8 g of composite nanosheets were then added and kneaded at a roller temperature of 70° C. for 20 min. Finally, 2 g of sulfur and 1.5 g of accelerator CBS were added, and the mixture was thinned 5 times at 70° C. and kneaded for 10 min to obtain a rubber mixture; S5: The rubber mix was injected into a mold and placed at 35°C for 24 hours, then vulcanized at 180°C and 15 MPa for 20 minutes, cooled to room temperature, and then treated at 100°C and 15 Pa in vacuum for 4 hours. The mold was then removed and immersed in a 10% by mass aqueous solution of ammonium perfluorooctanoate, treated at 80°C for 2 hours, washed with water, and dried to obtain a rubber stopper. S6: The positive electrode foil, carbon foil, guide needle, and electrolytic paper are rolled into a core package with a cylindrical winding structure. Then, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) with a particle size of 10-15 nm and electrolyte are filled into the core package, and the guide needle of the core package is passed through the hole of the rubber plug. The rubber plug and the core package are assembled together and placed in an aluminum shell. The aluminum shell is then sealed and waisted at an absolute pressure of 81 kPa to form a sealed cylindrical solid-liquid hybrid aluminum electrolytic capacitor with an internal pressure of 50 kPa.

[0025] Comparative Example 1: Compared with Example 1, this comparative example only replaces the "1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt" added in the preparation process of S1 with "N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt". The remaining steps and parameters are the same, and this comparative example will not be repeated. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0026] Comparative Example 2: Compared with Example 1, this comparative example only replaces the "N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt" added in the preparation process of S1 with "1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt". The remaining steps and parameters are the same, and this comparative example will not be repeated. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0027] Comparative Example 3: Compared with Example 1, this comparative example only does not add "ethyl trifluoroacetate" during the preparation of S1. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0028] Comparative Example 4: Compared with Example 1, this comparative example only does not add "fluoroethylene carbonate" during the preparation of S1. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0029] Comparative Example 5: Compared with Example 1, this comparative example only does not add "nano-silica" during the preparation of S1. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0030] Comparative Example 6: Compared with Example 1, this comparative example only does not add the "composite nanosheet" during the preparation of S4. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0031] Comparative Example 7: Compared with Example 1, this comparative example only does not add "modified nano-silica" during the preparation of S4. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a solid-liquid hybrid aluminum electrolytic capacitor is obtained.

[0032] Performance testing: Determination of boiling point at low pressure: The electrolytes prepared in Examples 1 to 3 of the present invention and Comparative Examples 1 to 7 were taken and their boiling points (° C.) at 30 kPa were measured. The test results are shown in Table 1. Determination of freezing point at low pressure: The electrolytes prepared in Examples 1 to 3 of the present invention and Comparative Examples 1 to 7 were taken and their freezing points (°C) at 30 kPa were measured. The test results are shown in Table 1. Determination of hardness: The hardness (Shore A) of the rubber stoppers prepared in Examples 1 to 3 and Comparative Examples 1 to 7 of the present invention was measured with reference to GB / T 531.1-2008, "Test method for indentation hardness of vulcanized or thermoplastic rubber - Part 1: Shore durometer method." The test results are shown in Table 1. Determination of deformation rate: The rubber stoppers prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were tested for deformation (%) under conditions where the internal pressure was higher than the external pressure and the pressure difference was 30 kPa. The test results are shown in Table 1. Table 1: Performance test results of Examples 1-3 and Comparative Examples 1-7

[0033] Data Analysis: As can be seen from Table 1, the electrolyte in the solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments prepared in the embodiment of the present invention 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.

[0034] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments, characterized in that: Including core package, poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonic acid), electrolyte, rubber plug, aluminum shell; The core package is formed by winding positive electrode foil, carbon foil, guide pins and electrolytic paper, and has a cylindrical winding structure; The electrolyte is obtained 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-silicon dioxide.

2. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that: The particle size of the poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) is 10-15 nm.

3. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that: The mass ratio of the 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.

4. 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.

5. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that: The preparation method of the rubber stopper is as follows: A1: Perfluoropolyether and nano-silica were mixed and ultrasonically treated at 50-70°C under nitrogen atmosphere for 30-60 minutes to obtain modified silica; A2: Add graphene oxide and molybdenum disulfide to N,N-dimethylformamide and perform ultrasonic treatment for 2-4 hours, and then vacuum dry to obtain composite nanosheets; A3: EPDM rubber and hydrogenated nitrile rubber are mixed and thinned for 5-10 times at 60-80°C. Then, carbon black, magnesium hydroxide, zinc oxide, and stearic acid are added in sequence and mixed at 60-80°C for 10-15 minutes. Then, modified silica and composite nanosheets are added and mixed at a roller temperature of 50-70°C for 15-20 minutes. Finally, sulfur and accelerator CBS are added and thinned for 3-5 times at 50-70°C and mixed for 5-10 minutes to obtain a rubber compound. A4: The rubber mix is ​​injected into a mold and placed at 20-35°C for 12-24 hours, followed by vulcanization treatment. The mold is then demoulded and immersed in an aqueous solution of ammonium perfluorooctanoate. The mixture is treated at 60-80°C for 1-2 hours, washed with water, and dried to obtain a rubber stopper.

6. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 5, characterized in that: The mass ratio of the perfluoropolyether to the nano-silicon dioxide in A1 is 10-20:

10.

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

1.

8. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 5, characterized in that: The mass ratio of the 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.

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

10. The solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environments according to claim 1, characterized in that: The preparation method of the solid-liquid hybrid aluminum electrolytic capacitor suitable for low-pressure environment is as follows: The core package is filled with conductive polymer and electrolyte, and the guide pin of the core package is passed through the hole of the rubber plug. The rubber plug and the core package are assembled together and placed in an aluminum shell. The aluminum shell is then sealed and waisted at 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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