Production process of high-stability anhydrous aluminum electrolytic capacitor and capacitor manufactured by production process

Abstract

The invention relates to a production process of a high-stability anhydrous aluminum electrolytic capacitor and the capacitor manufactured by the same, and the capacitor is manufactured by the following method: activating electrolytic paper: activating the surface of the electrolytic paper by adopting an activating agent containing a polyethylene glycol derivative, and removing a solvent to obtain activated electrolytic paper; the activated electrolytic paper, the anode foil, the activated electrolytic paper and the cathode foil are sequentially stacked and wound into a columnar core structure, in the process, the aluminum pad leading-out piece is riveted to the two electrode foils, and an element A is obtained; dipping: dipping the element A in the anhydrous electrolyte, so that the element A is fully dipped in the anhydrous electrolyte to obtain an element B; and assembling: assembling the element B, a shell, a sealing plug and an electronic component to obtain the anhydrous aluminum electrolytic capacitor. Through activating treatment, the adsorption efficiency of the element A on the water-free electrolyte is improved, meanwhile, the phenomenon that under the extreme condition, the capacitance is likely to be reduced can be reduced, and the durability of the element A is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic components, more particularly, it relates to a production process of high-stability anhydrous aluminum electrolytic capacitor and a capacitor prepared thereby. BACKGROUND

[0002] Aluminum electrolytic capacitor, as an important electronic component, plays a key role in electronic circuits. It uses aluminum foil treated by corrosion and oxidation film formation process as anode, forms a very thin layer of aluminum oxide (Al2O3) dielectric film on its surface, uses electrolyte as cathode, and is connected to external circuit through lead terminals. Aluminum electrolytic capacitor has the advantages of large unit volume capacitance, high cost performance, wide application range, etc., and is widely used in consumer electronics, industrial control, automotive electronics, communication equipment and other fields, mainly playing the roles of filtering, coupling, bypass, energy storage, etc., which can effectively smooth the voltage fluctuation in the circuit, transmit AC signals, isolate DC components and store energy, etc.

[0003] According to the state and characteristics of the electrolyte, aluminum electrolytic capacitors are mainly divided into two types: anhydrous aluminum electrolytic capacitors and anhydrous aluminum electrolytic capacitors. Anhydrous aluminum electrolytic capacitors usually use water-containing electrolyte, which has relatively low cost, but in high temperature environment, water is easy to evaporate, which leads to the performance degradation or even failure of the capacitor, limiting its use in high temperature application scenarios. Anhydrous aluminum electrolytic capacitors use anhydrous electrolyte, which can theoretically better adapt to high temperature environment, so they have potential application advantages in some fields with high temperature requirements.

[0004] However, the existing anhydrous aluminum electrolytic capacitors still have many problems in practical application, especially in extreme environmental conditions, their performance stability is difficult to meet the long-term use requirements.

[0005] In low temperature environment, the electrolytic paper in anhydrous aluminum electrolytic capacitor is prone to problems. When the environmental temperature is too low, the electrolyte may crystallize. Even if it is anhydrous electrolyte, if it contains some components that are easy to crystallize at low temperature, or the interaction between the electrolyte and the electrolytic paper causes local microstructure changes, it will affect the ion migration. Taking the common ion migration as an example, in normal working state, the free-moving ions (such as H +Under the action of an electric field, these ions can move freely in the electrolyte, participate in the formation of the double layer, and thus ensure that the capacitor has sufficient cathode equivalent area (A) and capacitance (C). However, in low-temperature freezing or similar crystalline states, these ions are fixed in the crystal structure of water or solvent and cannot effectively participate in the formation of the double layer, resulting in a decrease in the cathode equivalent area (A) and a significant reduction in the capacitance. This significant reduction in capacitance can seriously affect the normal operation of electronic equipment, leading to unstable circuit performance and even device failure.

[0006] In high-temperature environments, anhydrous aluminum electrolytic capacitors also face serious challenges. When a capacitor is operated at high temperatures for a long time, the electrolyte inside the capacitor gradually decreases due to various factors. On the one hand, high temperatures can accelerate the evaporation of the electrolyte, causing the solvent components in the electrolyte to gradually escape, resulting in changes in the concentration and composition of the electrolyte. On the other hand, high temperatures can also trigger decomposition reactions of the electrolyte, producing gases or other byproducts, further consuming the electrolyte. In addition, chemical consumption reactions may occur between the electrolyte and the electrode material at high temperatures, also reducing the effective amount of electrolyte. The reduction of electrolyte will directly lead to a significant decrease in capacitance (C), because the electrolyte is the medium for ion conduction, and its reduction will limit the transmission of ions and the storage capacity of electric charge. At the same time, the reduction of electrolyte will also cause the equivalent series resistance (ESR) to rise, because the electrolyte plays a role in reducing resistance in the capacitor, and its reduction will cause the resistance to increase when current passes through. The rise of ESR will generate more heat in the capacitor during operation, further accelerating the aging of the capacitor, shortening its service life, and even causing the capacitor to permanently fail.

[0007] In summary, the performance stability of existing anhydrous aluminum electrolytic capacitors in extreme environments needs to be addressed to meet the growing demand for high-performance and high-reliability capacitors in electronic equipment. Therefore, it is of great practical significance to develop an anhydrous aluminum electrolytic capacitor that can maintain stable performance in extreme environments. SUMMARY

[0008] The purpose of the present application is to overcome the above technical problems and provide a high-stability anhydrous aluminum electrolytic capacitor and its production process.

[0009] The first aspect relates to a production process of a high-stability anhydrous aluminum electrolytic capacitor, comprising the following steps: electrolytic paper activation: using an activator containing polyethylene glycol derivatives to activate the surface of the electrolytic paper, removing the solvent to obtain activated electrolytic paper; winding: stacking and winding the activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil into a cylindrical core structure, during which the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain a unit A; impregnation: impregnating the unit A in anhydrous electrolyte to make the unit A fully contain the anhydrous electrolyte to obtain a unit B; assembly: assembling the unit B with a shell, a sealing plug, and electronic components to obtain an anhydrous aluminum electrolytic capacitor; the polyethylene glycol derivatives in the activator are ethylene glycol-polydimethylsiloxane-polyethylene glycol and / or polyethylene glycol polypropylene glycol allyl ether; and the anhydrous electrolyte is composed of anhydrous solvent, lithium salt, ammonium salt, vinylene carbonate, trimethyl phosphate, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion.

[0010] By using the above technical solution, the electrolytic paper is activated using an activator containing ethylene glycol-polydimethylsiloxane-polyethylene glycol and / or polyethylene glycol polypropylene glycol allyl ether, which can form an activation film on the surface of the electrolytic paper, promote the adsorption of organic solvents, lock the electrolyte, prevent the electrolyte from volatilizing at high temperatures, reduce the loss of anhydrous electrolyte inside the electrolytic paper under extreme conditions, improve the adsorption efficiency and adsorption capacity of the electrolyte, and improve the stability of the anhydrous aluminum electrolytic capacitor; the activated electrolytic paper can quickly absorb anhydrous electrolyte, improve the impregnation efficiency, and thus improve the production efficiency; the anhydrous electrolyte composed of anhydrous solvent, lithium salt, ammonium salt, vinylene carbonate, trimethyl phosphate, and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion can conduct ions at extreme temperatures, reduce internal resistance, maintain conductivity, inhibit electrolyte decomposition and electrode material volume expansion, and improve cycle life and low-temperature charge-discharge efficiency. Ultimately, the prepared capacitor has better capacitance and can maintain better stability under extreme environments, providing its durability.

[0011] Preferably, the polyethylene glycol derivatives are composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol polypropylene glycol allyl ether.

[0012] By using the above technical solution, the polyethylene glycol derivatives are composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol polypropylene glycol allyl ether, which can have a synergistic effect, improving the stability of the anhydrous aluminum electrolytic capacitor; the polyethylene glycol polypropylene glycol allyl ether can form a dynamic adsorption layer on the surface of the electrolytic paper, reduce electrolyte loss, improve interface wettability, promote rapid electrolyte infiltration, and improve production efficiency; the combined action of the two helps the capacitor to operate stably under high and low temperature environments, prevents thermal decomposition at high temperatures, maintains ion conduction paths, prevents crystallization at low temperatures, and maintains electrolyte distribution uniformity.

[0013] Preferably, the activator of the polyethylene glycol derivative is composed of polyethylene glycol derivative, methylester olefin crosslinking polymer, polyamide polyamine epichlorohydrin resin, diluent.

[0014] By adopting the above technical scheme, the activator uniformly forms a stable activation layer on the surface of the electrolytic paper, enhances the wettability of the electrolytic paper, and promotes the adsorption capacity of the anhydrous electrolyte; the methylester olefin crosslinking polymer and the polyamide polyamine epichlorohydrin resin synergistically form a film, so that the activation layer is dense and porous, can adsorb the anhydrous electrolyte, and can reduce the loss of the electrolyte; the methylester olefin crosslinking polymer and the polyamide polyamine epichlorohydrin resin form a three-dimensional network structure film layer under the assistance of the diluent, so as to ensure that the film layer is uniform, dense and firmly combined with the electrolytic paper; the polyethylene glycol derivative reduces the surface tension of the electrolyte, promotes infiltration, and the ether bond coordinates with the lithium salt to stabilize the electrolyte system; the three-dimensional network structure after film formation adsorbs the electrolyte through capillary action and provides an ion transmission channel, and the cationic groups of the polyamide polyamine epichlorohydrin resin are electrostatically adsorbed on the surface of the electrolytic paper with negative charge, so as to reduce the loss of the electrolyte.

[0015] Preferably, the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion is obtained by dissolving poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) in an organic solvent, and then adding lye to adjust the pH value to neutral.

[0016] By adopting the above technical scheme, the prepared poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion is used for an anhydrous electrolyte, can form a conductive polymer layer on the surface of an electrode, reduce the interface impedance, improve the low-temperature charging and discharging efficiency, inhibit the volume expansion of the electrode material at high temperature, cooperate with the anhydrous solvent, lithium salt and ammonium salt to ensure the ion conduction of the electrolyte at extreme temperature, improve the ion migration rate, reduce the high-temperature internal resistance, maintain the low-temperature conductivity, and also make the prepared capacitor have a capacity retention rate of >80% at-60°C, and through the activator, the electrolytic paper quickly absorbs the anhydrous electrolyte, improves the impregnation efficiency, and further improves the production efficiency, and the capacitance of the capacitor is increased by 15%-20% compared with the traditional process, the capacity retention rate is >90% in the range of-60°C to 150°C, the impregnation time is shortened, and the quality is improved.

[0017] Preferably, the anhydrous solvent is a combination of propylene carbonate, γ-butyrolactone, ethylene glycol, and dimethylformamide.

[0018] By adopting the technical scheme, the water-free solvent is composed of propylene carbonate, gamma-butyrolactone, ethylene glycol and dimethylformamide, which can eliminate the problems of low-temperature crystallization and high-temperature volatilization caused by water molecules, ensure that the electrolyte can still conduct ions at extreme temperatures, cooperate with lithium salt and ammonium salt to form stable ion pairs, reduce the solvation energy barrier, improve the ion mobility, thereby reduce the internal resistance at high temperature and maintain the electrical conductivity at low temperature, and further improve the high and low temperature resistance of the water-free aluminum electrolytic capacitor.

[0019] Preferably, the water-free solvent is composed of gamma-butyrolactone and ethylene glycol.

[0020] By adopting the technical scheme, the water-free solvent is composed of gamma-butyrolactone and ethylene glycol, which belongs to the category of water-free solvent composed of gamma-butyrolactone, ethylene glycol and dimethylformamide, which can eliminate the problems of low-temperature crystallization and high-temperature volatilization caused by water molecules, cooperate with lithium salt and ammonium salt to form stable ion pairs, reduce the solvation energy barrier, improve the ion mobility, thereby reduce the internal resistance at high temperature and maintain the electrical conductivity at low temperature, ensure that the electrolyte can still conduct ions at extreme temperatures, and improve the performance stability of the capacitor in extreme environments.

[0021] Preferably, the lithium salt is one or more of lithium bistrifluoromethanesulfonimide, lithium hexafluorophosphate, lithium tetrafluoroborate and lithium bisoxalate borate.

[0022] By adopting the technical scheme, the lithium salt composed of one or more of lithium bistrifluoromethanesulfonimide, lithium hexafluorophosphate, lithium tetrafluoroborate and lithium bisoxalate borate can cooperate with the water-free solvent and the ammonium salt to form stable ion pairs, reduce the solvation energy barrier, improve the ion mobility, thereby reduce the internal resistance at high temperature and maintain the electrical conductivity at low temperature, and also improve the capacitance of the capacitor, so that the capacitance retention rate of the capacitor is >90% in the range of-60℃ to 150℃.

[0023] Preferably, the ammonium salt is one or more of quaternary ammonium tetrafluoroborate, nitrogen-substituted bicyclooctane quaternary ammonium salt and tetraalkylammonium salt.

[0024] By adopting the technical scheme, the ammonium salt is one or more of quaternary ammonium tetrafluoroborate, nitrogen-substituted bicyclooctane quaternary ammonium salt and tetraalkylammonium salt, which cooperates with the water-free solvent and the lithium salt to form stable ion pairs, reduce the solvation energy barrier, improve the ion mobility, thereby reduce the internal resistance at high temperature and maintain the electrical conductivity at low temperature, which helps the water-free aluminum electrolytic capacitor prepared to maintain stable performance in extreme environments (-60℃ to 150℃), realize the effects of capacitance improvement, extreme environment adaptability enhancement and production efficiency improvement.

[0025] Preferably, the electrolytic paper is prepared from cellulose fiber slurry or random fiber weaving.

[0026] By adopting the above technical solution, the electrolytic paper made of cellulose fiber slurry or fiber random weaving is used as raw material, and the surface is activated by using the activator containing polyethylene glycol derivative, the activated electrolytic paper is stacked and wound in sequence, the anhydrous electrolyte is impregnated, and the assembly is carried out, so that the anhydrous aluminum electrolytic capacitor prepared has high capacitance and excellent stability in extreme environment, and the activated electrolytic paper can quickly absorb the anhydrous electrolyte, thereby improving the impregnation efficiency and production efficiency.

[0027] In the second aspect, a high-stability anhydrous aluminum electrolytic capacitor includes a shell, an element, and a sealing plug. The element is contained in the shell, and the sealing plug is sealed in the opening of the shell and completely seals the element in the shell. The element is prepared by the high-stability anhydrous aluminum electrolytic capacitor production process.

[0028] By adopting the above technical solution, the production process of the anhydrous aluminum electrolytic capacitor can improve the performance of the capacitor. In the activation process of the electrolytic paper, the activator containing the specific polyethylene glycol derivative can form an activation film on the surface of the electrolytic paper, promote the adsorption of the anhydrous electrolyte, reduce the electrolyte loss under extreme conditions, improve the liquid absorption efficiency, shorten the impregnation time, and improve the production efficiency. The synergistic effect of the components of the anhydrous electrolyte enables the capacitor to have high and low temperature resistance, reduce the internal resistance, maintain the conductivity, inhibit the decomposition of the electrolyte, improve the cycle life, reduce the flammability, enhance the solubility of lithium salt, reduce the interface impedance, and inhibit the volume expansion of the electrode material. The final capacitor has improved capacitance, enhanced adaptability to extreme environments, and improved production efficiency.

[0029] In summary, the present application has at least one of the following beneficial technical effects: 1. Improved capacitance: through the optimization of the interface between the electrolyte and the electrode, the capacitance is improved by 15% compared with the traditional process, solving the problem of significant decrease in capacitance of existing anhydrous aluminum electrolytic capacitors under extreme environments; 2. Enhanced adaptability to extreme environments: the capacity retention rate is > 90% in the range of -60℃ to 150℃, overcoming the poor performance stability of existing products under extreme environments; 3. Improved production efficiency: the impregnation time is shortened to 1 / 3 of the traditional process, and the yield is improved by 15%, solving the problem of low production efficiency of existing processes. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a high-stability anhydrous aluminum electrolytic capacitor; Figure 2 A schematic diagram of the winding process of a high-stability anhydrous aluminum electrolytic capacitor; Figure 3 A schematic diagram of the impregnation and assembly of a high-stability anhydrous aluminum electrolytic capacitor. DETAILED DESCRIPTION

[0031] The following is combined with Figures 1-3 The present application is further described in detail with reference to the accompanying drawings and examples.

[0032] Introduction of some raw materials: Methyl methacrylate cross-linked polymer CAS number: 25777-71-3, molecular formula C15H22O6, molecular weight 298.34, density 1.19 g / mL at 25°C, morphological microbeads color white, particle size 1-10 microns (the solvent easily penetrates into the cross-linked polymer, causing the macromolecular chains in the polymer network structure to stretch and expand its volume); Ethylene glycol-polydimethylsiloxane-polyethylene glycol: molecular formula: [C2H4O] n [C2H6OSi] m [C2H4O] n , wherein n and m are both 10-50; main chain structure: ABA triblock copolymer; Polyethylene glycol polypropylene glycol allyl ether: CAS: 9041-33-2; Electrolytic paper made of cellulose fiber pulp, specification 90-150g / m 2 , the liquid absorption rate of the anhydrous electrolyte of this application is 300%-500% (referring to the washing rate under saturated state); Electrolytic paper is made of fiber (island fiber, which is composed of 70% polyester (PET) and 30% polyamide (PA) polymers. Polyester is used as the continuous phase ("sea"), and polyamide is evenly distributed in it in the form of dispersed phase ("island")) randomly woven, with a specification of 80-100g / m 2 ; The number average molecular weight of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) is 200-500. Example

[0033] Example 1 A high stability anhydrous aluminum electrolytic capacitor, such as Figure 1 As shown, it includes a shell, an element, and a sealing plug. The element is accommodated inside the shell, and the sealing plug seals the opening of the shell and completely seals the element inside the shell.

[0034] The production process of the high stability anhydrous aluminum electrolytic capacitor: Electrolytic paper activation: Use an activator containing polyethylene glycol derivatives to activate the surface of the electrolytic paper for 2 minutes, heat it to 105°C to remove all the solvent, and obtain activated electrolytic paper; Winding: Activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil are stacked and wound in sequence to form a cylindrical core structure. During this process, the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain element A; Immersion: Substrate A is immersed in anhydrous electrolyte, soaking time is 10 min, soaking temperature is 50℃, so that the substrate A is fully immersed in the anhydrous electrolyte, and substrate B is obtained; Assembly: Substrate B is assembled with the shell, sealing plug and electronic components to obtain an anhydrous aluminum electrolytic capacitor, which is referred to as Figure 1 , and the winding, immersion and assembly process is referred to as Figure 2 and Figure 3 schematic diagram, the above pictures are for reference only; The activator containing polyethylene glycol derivative is composed of polyethylene glycol derivative and water in a weight ratio of 1:9. The polyethylene glycol derivative in the activator of polyethylene glycol derivative is ethylene glycol-polydimethylsiloxane-polyethylene glycol; the anhydrous electrolyte is composed of anhydrous solvent, lithium salt, ammonium salt, vinylene carbonate, trimethyl phosphate, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) dispersion in a weight ratio of 8:0.5:0.5:0.5:0.5.

[0035] The ammonium salt is composed of quaternary ammonium tetrafluoroborate and nitrogen-substituted bicyclooctane quaternary ammonium salt in a weight ratio of 1:1.

[0036] The lithium salt is composed of lithium bis(trifluoromethanesulfonylimide) and lithium bis(oxalate)borate in a weight ratio of 1:1.

[0037] The anhydrous solvent is composed of y-butyrolactone and ethylene glycol in a weight ratio of 2:3. The electrolytic paper is composed of cellulose fiber slurry.

[0038] Example 2 Example 2 is different from example 1 in that the activator containing polyethylene glycol derivative is composed of polyethylene glycol derivative, methyl oleate crosslinking polymer, polyamide polyamine epichlorohydrin resin, diluent (water) in a weight ratio.

[0039] Example 3 Example 3 is different from example 2 in that the polyethylene glycol derivative is polyethylene glycol polypropylene glycol allyl ether.

[0040] Example 4 Example 4 is different from example 2 in that the polyethylene glycol derivative is composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol polypropylene glycol allyl ether in a weight ratio of 1:1.

[0041] Example 5 Example 5 is different from example 4 in that the electrolytic paper is made of fiber random weaving.

[0042] Comparative example Comparative example 1 Comparative example 1 is different from example 1 in that there is no electrolyte activation step, specifically: Winding: Activated electrolytic paper, anode foil, electrolytic paper, cathode foil are stacked in turn and wound into a cylindrical core structure, and during the process, the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain element A; Immersion: Immersing element A in anhydrous electrolyte for 10 min at 50℃ to fully soak element A in anhydrous electrolyte to obtain element B; Assembly: Assembling element B with the shell, sealing plug and electronic components to obtain an anhydrous aluminum electrolytic capacitor.

[0043] Comparative Example 2 Comparative Example 2 differs from Example 1 in that the polyethylene glycol derivative is replaced with polyethylene glycol (relative molecular weight 200-400) in equal amount.

[0044] Comparative Example 3 Comparative Example 3 differs from Example 1 in that the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion is replaced with anhydrous solvent in equal amount.

[0045] Comparative Example 4 Comparative Example 4 differs from Example 1 in that the vinylene carbonate is replaced with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion in equal amount.

[0046] Performance Test The capacitors obtained in Examples 1-5 and Comparative Examples 1-4 were subjected to the following performance tests.

[0047] Detection method / test method Experiment (I) The capacitance was detected according to GB / T 17702-2021, and when the capacitance was greater than 60000 μF, it was recorded as qualified, otherwise it was unqualified.

[0048] Experiment (II) Resistance to extreme environments: 1) The capacitor was placed in an environment with a temperature of -60℃ and a humidity of 30% for 1000h to obtain a sample to be tested a; 2) The capacitor was placed in an environment with a temperature of 150℃ and a humidity of 45% for 1000h to obtain a sample to be tested b; 3) The capacitor was placed in an environment with a temperature of -60℃ and a humidity of 30% for 24h, and then placed in an environment with a temperature of -60℃ and a humidity of 30% for 24h, and the cycle was repeated for 20 times to obtain a sample to be tested c; The capacitances of samples a, b and c were detected according to the test method in Experiment (I).

[0049] The residual rate of the capacitance of sample a is equal to the capacitance of sample a divided by the capacitance in experiment (I) multiplied by 100%; The residual rate of the capacitance of sample b is equal to the capacitance of sample b divided by the capacitance in experiment (I) multiplied by 100%; The residual rate of the capacitance of sample c is equal to the capacitance of sample c divided by the capacitance in experiment (I) multiplied by 100%.

[0050] The above residual rate of the capacitance is divided into grades: S: less than 2%; A: 2%≤ the residual rate of the capacitance <5%; B: 5%≤ the residual rate of the capacitance <10%; C: 10%≤ the residual rate of the capacitance ≤15%; D: greater than 15%.

[0051] If the residual rate of the capacitance of sample a is in grade A (2%≤ the residual rate of the capacitance <5%), it indicates that the electrolytic paper still maintains a better experiment (III) at a low temperature for a long time Soaking time: as the soaking time is prolonged, the adsorption amount changes little, which indicates that the adsorption rate is good, and further indicates that the adsorption effect of the electrolytic paper on the anhydrous electrolyte is good. The saturation rate is calculated, which is equal to the adsorption amount of the anhydrous electrolyte of the element after soaking for 5 min divided by the adsorption amount of the anhydrous electrolyte of the element after soaking for 10 min multiplied by 100%.

[0052] The above experiment is specifically shown in Table 1; Table 1 Experimental data of examples 1-5 and comparative examples 1-4 It can be seen from examples 1 and comparative example 1 and Table 1 that the capacitance of comparative example 1 appears unqualified, the high and low temperature resistance level of comparative example 1 is in grade D, and the saturation rate of comparative example 1 is lower than that of example 1, which indicates that the electrolytic paper produced by the production process of the application can efficiently adsorb anhydrous electrolyte and reduce the capacitance loss in extreme environment.

[0053] It can be seen from comparative example 1 and comparative example 2 and Table 1 that the high and low temperature resistance level of comparative example 2 is in grade C, and the saturation rate of comparative example 2 is higher than that of example 1, which indicates that the polyethylene glycol derivative is used as an electrolytic paper activator, which has a better activation effect, and can further improve the resistance of the capacitor to extreme environment and the durability of the capacitor in combination with the anhydrous electrolyte of the application.

[0054] As can be seen from the comparison of Comparative Example 1 and Example 2 and in combination with Table 1, Example 2 uses the activator containing the polyethylene glycol derivative, which is composed of the polyethylene glycol derivative, the methylester crosslinking polymer of alkenoic acid, the polyamide polyamine epichlorohydrin resin and the diluent (water), compared with Example 1 (the activator containing the polyethylene glycol derivative is composed of the polyethylene glycol derivative and the diluent), the saturation rate of Example 2 is increased to 98.22% (the saturation rate of Example 1 is 94.47%), and the tolerance level under extreme environment of Example 2 is increased to A level (Example 1 is B level), which indicates that the activator containing the polyethylene glycol derivative, which is composed of the polyethylene glycol derivative, the methylester crosslinking polymer of alkenoic acid, the polyamide polyamine epichlorohydrin resin and the diluent (water), has better film forming, promotes the anhydrous electrolytic adsorption and reduces the evaporation of the anhydrous electrolyte, etc., and cooperates with the anhydrous electrolyte of the application, so that the anhydrous aluminum electrolytic capacitor has higher stability, and when being in the extreme environment for a long time, the quality change of the anhydrous electrolyte is reduced, and the capacitance and the durability are affected.

[0055] As can be seen from the comparison of Comparative Example 2-3 and Example 4, when the polyethylene glycol derivative is composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol polypropylene glycol allyl ether with a weight ratio of 1:1 in Example 4, the tolerance level under extreme environment is increased to S level (one of them is used in Comparative Example 2-3, and the tolerance level is S level), which indicates that the two compounds have a synergistic effect, further improve the stability of the anhydrous aluminum electrolytic capacitor, and the active layer formed cooperates with the anhydrous electrolyte of the application to obtain better adsorption effect.

[0056] As can be seen from the comparison of Comparative Example 4 and Example 5, the electrolytic paper is made of randomly woven fibers, which cooperates with the activation process and the impregnation process of the application, so that the content of the anhydrous electrolyte in the final capacitor is higher, the capacitance is further improved, the capacitance loss under the extreme environment for a long time is reduced, the stability of the capacitor is improved, and the quality and durability are ensured.

[0057] The specific embodiments are only an explanation of the application, and are not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the patent law.

Claims

1. A production process for high-stability anhydrous aluminum electrolytic capacitors, characterized in that: Prepared by the following method: Electrolytic paper activation: Activate the surface of the electrolytic paper using an activator containing a polyethylene glycol derivative, remove the solvent, and obtain activated electrolytic paper; Winding: Activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil are stacked and wound in sequence to form a cylindrical core structure. During this process, the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain element A; Impregnation: immersing element A in an anhydrous electrolyte solution to fully impregnate element A with the anhydrous electrolyte solution to obtain element B; Assembly: Assemble element B with the housing, sealing plug, and electronic components to obtain an anhydrous aluminum electrolytic capacitor; The polyethylene glycol derivative in the activator of the polyethylene glycol derivative is ethylene glycol-polydimethylsiloxane-polyethylene glycol and / or polyethylene glycol polypropylene glycol allyl ether; The anhydrous electrolyte consists of an anhydrous solvent, lithium salt, ammonium salt, vinylene carbonate, trimethyl phosphate, and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) dispersion.

2. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The polyethylene glycol derivative consists of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol polypropylene glycol allyl ether.

3. Polyethylene glycol derivatives are composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol polypropylene glycol allyl ether to play a synergistic role The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1 is characterized in that: The activator of the polyethylene glycol derivative consists of polyethylene glycol derivative, methyl acrylate cross-linked polymer, polyamide polyamine epichlorohydrin resin and diluent.

4. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) dispersion is obtained by dissolving poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) in an organic solvent and then adding alkaline solution to adjust the pH value to neutral.

5. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The anhydrous solvent is a combination of multiple types of propylene carbonate, γ-butyrolactone, ethylene glycol, and dimethylformamide.

6. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 5, characterized in that: The anhydrous solvent consists of γ-butyrolactone and ethylene glycol.

7. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium bis(oxalatoborate).

8. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The ammonium salt is a combination of one or more of tetrafluoroborate quaternary ammonium salt, nitrogen-substituted bicyclooctane quaternary ammonium salt, and tetraalkylammonium salt.

9. The production process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The electrolytic paper is made from cellulose fiber pulp or random fiber weaving.

10. A high-stability anhydrous aluminum electrolytic capacitor comprising a housing, an element, and a sealing plug, wherein the element is accommodated within the housing, the sealing plug blocks an opening of the housing, and completely seals the element within the housing, characterized in that: The anhydrous aluminum electrolytic capacitor is manufactured by a production process of an anhydrous aluminum electrolytic capacitor with high stability.

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