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

Abstract

This application relates to a manufacturing process for a high-stability anhydrous aluminum electrolytic capacitor and the capacitor obtained therefrom. The capacitor is manufactured using the following method: Electrolytic paper activation: Electrolytic paper is surface-activated using an activator containing polyethylene glycol derivatives to remove the solvent, resulting in activated electrolytic paper; Winding: Activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil are sequentially stacked and wound into a cylindrical core structure. During this process, aluminum pad leads are riveted to the two electrode foils, resulting in element A; Impregnation: Element A is impregnated in anhydrous electrolyte to ensure it is fully immersed, resulting in element B; Assembly: Element B is assembled with a casing, sealing plug, and electronic components to obtain the anhydrous aluminum electrolytic capacitor. This application improves the adsorption efficiency of element A for anhydrous electrolyte through activation treatment, while also reducing the likelihood of capacitance reduction under extreme conditions, thus improving its durability.

Description

Technical Field

[0001] This application relates to the field of electronic components, and more specifically, it relates to a manufacturing process for a high-stability anhydrous aluminum electrolytic capacitor and the capacitor obtained therefrom. Background Technology

[0002] Aluminum electrolytic capacitors, as important electronic components, play a crucial role in electronic circuits. They utilize aluminum foil treated with etching and oxide film formation processes as the anode, forming an extremely thin aluminum oxide (Al2O3) dielectric film on its surface, and an electrolyte as the cathode, connected to an external circuit through lead-out terminals. Aluminum electrolytic capacitors offer advantages such as large capacitance per unit volume, high cost-effectiveness, and wide applicability, and are widely used in consumer electronics, industrial control, automotive electronics, and communication equipment. Their main functions include filtering, coupling, bypassing, and energy storage, effectively smoothing voltage fluctuations in circuits, transmitting AC signals, isolating DC components, and storing electrical energy.

[0003] Based on the state and characteristics of the electrolyte, aluminum electrolytic capacitors are mainly divided into two types: aqueous aluminum electrolytic capacitors and anhydrous aluminum electrolytic capacitors. Aqueous aluminum electrolytic capacitors typically use an aqueous electrolyte, which is relatively inexpensive. However, at high temperatures, the moisture easily evaporates, leading to a decrease in capacitor performance or even failure, limiting their use in high-temperature applications. Anhydrous aluminum electrolytic capacitors, on the other hand, use an anhydrous electrolyte, which theoretically allows them to better withstand high-temperature environments, thus offering potential advantages in fields with stringent temperature requirements.

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

[0005] In low-temperature environments, the electrolytic paper in anhydrous aluminum electrolytic capacitors is prone to problems. When the ambient temperature is too low, the electrolyte may crystallize. Even with anhydrous electrolytes, if they contain components that easily crystallize at low temperatures, or if the interaction between the electrolyte and the electrolytic paper causes localized microstructural changes, it will affect ion migration. Taking common ion migration as an example, under normal operating conditions, freely moving ions in the electrolyte (such as H+)... +Hydroxyl ions (OH- or solute ions in organic electrolytes) can move freely in the electrolyte under the influence of an electric field, participating in the formation of the electric double layer, thus ensuring 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 electric double layer, resulting in a reduction in cathode equivalent area (A) and consequently a significant decrease in capacitance. This drastic decrease in capacitance can seriously affect the normal operation of electronic equipment, leading to unstable circuit performance and even equipment failure.

[0006] Anhydrous aluminum electrolytic capacitors also face severe challenges in high-temperature environments. During prolonged high-temperature operation, the electrolyte inside the capacitor gradually decreases due to various factors. Firstly, high temperatures accelerate electrolyte evaporation, causing solvent components to escape and altering the electrolyte's concentration and composition. Secondly, high temperatures may trigger electrolyte decomposition reactions, producing gases or other byproducts that further consume the electrolyte. Furthermore, chemical consumption reactions may occur between the electrolyte and electrode materials at high temperatures, also reducing the effective amount of electrolyte. This reduction in electrolyte directly leads to a significant decrease in capacitance (C), as the electrolyte is the medium for ion conduction, and its reduction limits ion transport and charge storage capacity. Simultaneously, the reduction in electrolyte also causes an increase in equivalent series resistance (ESR). This is because the electrolyte reduces resistance within the capacitor, and its reduction increases resistance to current flow. The increase in ESR causes the capacitor to generate more heat during operation, further accelerating capacitor aging, shortening its lifespan, and potentially leading to permanent failure.

[0007] In summary, the performance stability of existing anhydrous aluminum electrolytic capacitors under extreme environments urgently needs to be addressed to meet the growing demand for high-performance, high-reliability capacitors in electronic devices. Therefore, developing anhydrous aluminum electrolytic capacitors capable of maintaining stable performance under extreme conditions is of significant practical importance. Summary of the Invention

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

[0009] Firstly, a manufacturing process for a high-stability anhydrous aluminum electrolytic capacitor includes the following steps: Electrolytic paper activation: Electrolytic paper is surface-activated using an activator containing polyethylene glycol derivatives to remove the solvent, resulting in activated electrolytic paper; Winding: Activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil are sequentially stacked and wound into a cylindrical core structure. During this process, aluminum pad leads are riveted to the two electrode foils, resulting in element A; Impregnation: Element A is impregnated in anhydrous electrolyte to ensure that element A is fully contained in the electrolyte. Immersing in anhydrous electrolyte yields element B; assembly: element B is assembled with the shell, sealing plug, and electronic components to obtain anhydrous aluminum electrolytic capacitor; the polyethylene glycol derivative in the activator is ethylene glycol-polydimethylsiloxane-polyethylene glycol and / or polyethylene glycol-polypropylene glycol allyl ether; the anhydrous electrolyte is composed of anhydrous solvent, lithium salt, ammonium salt, vinylene carbonate, trimethyl phosphate, and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) dispersion.

[0010] By adopting 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. This forms an activation film on the surface of the electrolytic paper, promoting the adsorption of organic solvents and locking in the electrolyte. This prevents the electrolyte from evaporating under high temperatures and reduces the loss of anhydrous electrolyte inside the electrolytic paper under extreme conditions. It also improves the adsorption efficiency and amount of electrolyte, thereby enhancing the stability of the anhydrous aluminum electrolytic capacitor. The activated electrolytic paper can quickly absorb the anhydrous electrolyte, improving impregnation efficiency and thus production efficiency. The anhydrous electrolyte, composed of anhydrous solvent, lithium salt, ammonium salt, vinylene carbonate, trimethyl phosphate, and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic 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, this results in capacitors with better capacitance and stability under extreme conditions, thus enhancing their durability.

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

[0012] By adopting the above technical solution, the polyethylene glycol derivative, composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol-polypropylene glycol allyl ether, can play a synergistic role in improving the stability of anhydrous aluminum electrolytic capacitors. Among them, polyethylene glycol-polypropylene glycol allyl ether can form a dynamic adsorption layer on the surface of electrolytic paper, reducing electrolyte loss, improving interfacial wettability, promoting rapid electrolyte wetting, and improving production efficiency. The combined effect of the two helps the capacitor operate stably in high and low temperature environments, preventing thermal decomposition and maintaining ion conduction pathways at high temperatures, and preventing crystallization and maintaining electrolyte uniformity at low temperatures.

[0013] Preferably, the activator of the polyethylene glycol derivative is composed of polyethylene glycol derivative, methyl methacrylate crosspolymer, polyamide polyamine epichlorohydrin resin, and diluent.

[0014] By adopting the above technical solution, the activator uniformly forms a stable activation layer on the surface of the electrolytic paper, enhancing the hydrophilicity of the electrolytic paper and promoting its adsorption capacity for anhydrous electrolyte. The methyl acrylate crosslinked polymer and polyamide polyamine epichlorohydrin resin synergistically form a film, making the activation layer structure dense and porous, which can both adsorb anhydrous electrolyte and reduce electrolyte loss. With the assistance of a diluent, the methyl acrylate crosslinked polymer and polyamide polyamine epichlorohydrin resin form a three-dimensional network structure film layer, ensuring that the film layer is uniform, dense, and firmly bonded to the electrolytic paper. The polyethylene glycol derivative reduces the surface tension of the electrolyte and promotes wetting, and its ether bonds coordinate with lithium salts to stabilize the electrolyte system. The three-dimensional network structure after film formation adsorbs electrolyte through capillary action and provides ion transport channels. The cationic groups of polyamide polyamine epichlorohydrin resin electrostatically adsorb the negative charge on the surface of the electrolytic paper, reducing electrolyte loss.

[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 an alkaline solution to adjust the pH value to neutral.

[0016] By adopting the above technical solution, the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion prepared for use as an anhydrous electrolyte can form a conductive polymer layer on the electrode surface, reduce interfacial impedance, improve low-temperature charge and discharge efficiency, and suppress the volume expansion of electrode materials at high temperatures. In combination with anhydrous solvents, lithium salts, and ammonium salts, it ensures the conduction of ions in the electrolyte at extreme temperatures, improves ion mobility, reduces high-temperature internal resistance, and maintains low-temperature conductivity. It also enables the capacitors to retain a capacity of >80% at -60℃. Furthermore, the activator enables the electrolytic paper to quickly absorb the anhydrous electrolyte, improving impregnation efficiency and thus production efficiency. The capacitor capacitance is increased by 15%-20% compared to traditional processes, with a capacity retention of >90% in the range of -60℃ to 150℃, shortened impregnation time, and improved quality.

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

[0018] By adopting the above technical solution, the anhydrous solvent is selected from a combination of multiple substances including propylene carbonate, γ-butyrolactone, ethylene glycol, and dimethylformamide. This eliminates the problem of low-temperature crystallization or high-temperature volatilization caused by water molecules, ensuring that the electrolyte can still conduct ions at extreme temperatures. It can also cooperate with lithium salts and ammonium salts to form stable ion pairs, reduce the solvation energy barrier, and improve ion mobility. This reduces internal resistance at high temperatures and maintains conductivity at low temperatures, thereby improving the high and low temperature tolerance of the anhydrous aluminum electrolytic capacitor.

[0019] Preferably, the anhydrous solvent is composed of γ-butyrolactone and ethylene glycol.

[0020] By adopting the above technical solution, the anhydrous solvent is composed of γ-butyrolactone and ethylene glycol, which belongs to the category of anhydrous solvents consisting of multiple of γ-butyrolactone, ethylene glycol, and dimethylformamide. It can eliminate the problem of low-temperature crystallization or high-temperature volatilization caused by water molecules. In combination with lithium salt and ammonium salt, it forms a stable ion pair, reduces the solvation energy barrier, and improves ion mobility. This reduces internal resistance at high temperatures and maintains conductivity at low temperatures, ensuring that the electrolyte can still conduct ions at extreme temperatures and improving the performance stability of the capacitor in extreme environments.

[0021] Preferably, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium dioxalate borate.

[0022] By adopting the above technical solutions, lithium salts composed of one or more combinations of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium dioxalateborate can form stable ion pairs with anhydrous solvents and ammonium salts, thereby reducing the solvation energy barrier and improving ion mobility. This reduces internal resistance at high temperatures and maintains conductivity at low temperatures, and also increases the capacitance of capacitors, enabling the capacitor to retain >90% of its capacitance in the range of -60℃ to 150℃.

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

[0024] By adopting the above technical solution, the ammonium salt is selected from one or more of tetrafluoroborate quaternary ammonium salt, nitrogen-substituted bicyclooctane quaternary ammonium salt, and tetraalkyl ammonium salt, which are combined with anhydrous solvent and lithium salt to form stable ion pairs, reduce the solvation energy barrier, and improve ion mobility. This reduces internal resistance at high temperatures and maintains conductivity at low temperatures, which helps the anhydrous aluminum electrolytic capacitor to maintain stable performance in extreme environments (-60℃ to 150℃), achieving effects such as increased capacitance, enhanced adaptability to extreme environments, and improved production efficiency.

[0025] Preferably, the electrolytic paper is made from cellulose fiber pulp or by random weaving of fibers.

[0026] By adopting the above technical solution, using electrolytic paper made from cellulose fiber pulp or random fiber weaving as raw material, and combining it with the steps of surface activation with an activator containing polyethylene glycol derivatives, sequentially layering and winding the activated electrolytic paper, impregnating it with anhydrous electrolyte, and assembling it, the resulting anhydrous aluminum electrolytic capacitor has high capacitance and stability against extreme environments. It also allows the activated electrolytic paper to quickly absorb the anhydrous electrolyte, improving impregnation efficiency and production efficiency.

[0027] Secondly, a high-stability anhydrous aluminum electrolytic capacitor includes a shell, a core, and a sealing plug. The core is housed inside the shell, and the sealing plug seals the opening of the shell, completely sealing the core within the shell. The core is manufactured using the aforementioned high-stability anhydrous aluminum electrolytic capacitor manufacturing process.

[0028] By adopting the above technical solutions, the production process of anhydrous aluminum electrolytic capacitors can improve capacitor performance. In the electrolytic paper activation stage, an activator containing specific polyethylene glycol derivatives can form an activation film on the electrolytic paper surface, promoting the adsorption of anhydrous electrolyte, reducing electrolyte loss under extreme conditions, improving absorption efficiency, shortening impregnation time, and increasing production efficiency. The synergistic effect of the components of the anhydrous electrolyte enables the capacitor to have high and low temperature tolerance, reduces internal resistance, maintains conductivity, inhibits electrolyte decomposition, improves cycle life, reduces flammability, enhances lithium salt solubility, reduces interfacial impedance, and inhibits electrode material volume expansion. The resulting capacitor has increased capacitance, enhanced adaptability to extreme environments, and improved production efficiency.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. Increased capacitance: Through optimization of the electrolyte-electrode interface, the capacitance is increased by 15% compared to traditional processes, solving the problem of significant capacitance reduction in existing anhydrous aluminum electrolytic capacitors under extreme environments;

[0031] 2. Enhanced adaptability to extreme environments: Capacity retention is >90% within the temperature range of -60℃ to 150℃, overcoming the shortcomings of existing products in terms of poor performance stability under extreme environments;

[0032] 3. Improved production efficiency: The soaking time is reduced to 1 / 3 of the traditional process, and the yield rate is increased by 15%, solving the problem of low production efficiency of the existing process. Attached Figure Description

[0033] Figure 1 A schematic diagram of a high-stability anhydrous aluminum electrolytic capacitor;

[0034] Figure 2 A schematic diagram of the winding process for a high-stability anhydrous aluminum electrolytic capacitor;

[0035] Figure 3 A schematic diagram of the impregnation and assembly of a high-stability anhydrous aluminum electrolytic capacitor. Detailed Implementation

[0036] The following is in conjunction with the appendix Figure 1-3 The present application will be further described in detail with reference to the embodiments.

[0037] Introduction to some raw materials:

[0038] Methyl methacrylate crosslinked polymer CAS No.: 25777-71-3, molecular formula C15H22O6, molecular weight 298.34, density 1.19 g / mL. At 25℃, it is in the form of microbeads, white in color, with a particle size of 1-10 micrometers (the solvent easily penetrates into the crosslinked polymer, causing the extension of the macromolecular chains in the polymer network structure, resulting in its volume expansion).

[0039] Ethylene glycol-polydimethylsiloxane-polyethylene glycol: Molecular formula: [C2H4O] n [C2H6OSi] m [C2H4O] n Where n and m are both 10-50; main chain structure: ABA triblock copolymer;

[0040] Polyethylene glycol polypropylene glycol allyl ether: CAS: 9041-33-2;

[0041] Electrolytic paper made from cellulose fiber pulp, with specifications of 90-150 g / m² 2 The absorption rate of the anhydrous electrolyte in this application is 300%-500% (referring to the washing liquid rate under saturation).

[0042] Electrolytic paper is made by random weaving of fibers (island fibers, composed of 70% polyester (PET) and 30% polyamide (PA) polymers. Polyester is the continuous phase ("sea"), while polyamide is uniformly distributed in the form of a dispersed phase ("island"), with a specification of 80-100 g / m². 2 ;

[0043] The number average molecular weight of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) is 200-500.

[0044] Example

[0045] Example 1

[0046] A high-stability anhydrous aluminum electrolytic capacitor, such as Figure 1 As shown, it includes a shell, a component, and a sealing plug. The component is housed inside the shell, and the sealing plug blocks the opening of the shell, completely sealing the component inside the shell.

[0047] The manufacturing process of this high-stability anhydrous aluminum electrolytic capacitor:

[0048] Electrolytic paper activation: Electrolytic paper is surface activated using an activator containing polyethylene glycol derivatives for 2 minutes. The solvent is then removed by heating to 105°C to obtain activated electrolytic paper.

[0049] Winding: The activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil are sequentially stacked and wound into a columnar core structure. During this process, the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain element A.

[0050] Impregnation: Immerse seed A in anhydrous electrolyte for 10 minutes at a temperature of 50°C to ensure that seed A is fully impregnated with the anhydrous electrolyte and obtain seed B.

[0051] Assembly: Element B is assembled with the casing, sealing plug, and electronic components to obtain an anhydrous aluminum electrolytic capacitor. This anhydrous aluminum electrolytic capacitor is a reference... Figure 1 Its winding, impregnation, and assembly processes are referenced. Figure 2 and Figure 3 This is an illustration; the above images are for reference only.

[0052] The activator containing polyethylene glycol derivatives is composed of polyethylene glycol derivatives and water in a weight ratio of 1:9. The polyethylene glycol derivative in the activator is ethylene glycol-polydimethylsiloxane-polyethylene glycol; 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 in a weight ratio of 8:0.5:0.5:0.5:0.5.

[0053] The ammonium salt is composed of tetrafluoroborate quaternary ammonium salt and nitrogen-substituted bicyclooctane quaternary ammonium salt in a weight ratio of 1:1.

[0054] The lithium salt is composed of lithium bis(trifluoromethanesulfonyl)imide and lithium dioxalateborate in a weight ratio of 1:1.

[0055] The anhydrous solvent consists of γ-butyrolactone and ethylene glycol in a weight ratio of 2:3. Electrolytic paper is made from cellulose fiber pulp.

[0056] Example 2

[0057] The difference between Example 2 and Example 1 is that the activator containing polyethylene glycol derivative is composed of polyethylene glycol derivative, methyl methacrylate crosspolymer, polyamide polyamine epichlorohydrin resin, and diluent (water) in a weight ratio.

[0058] Example 3

[0059] The difference between Example 3 and Example 2 is that the polyethylene glycol derivative is polyethylene glycol polypropylene glycol allyl ether.

[0060] Example 4

[0061] The difference between Example 4 and Example 2 is 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.

[0062] Example 5

[0063] The difference between Example 5 and Example 4 is that the electrolytic paper is made by random weaving of fibers.

[0064] Comparative Example

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that there is no electrolyte activation step, specifically:

[0067] Winding: The activated electrolytic paper, anode foil, electrolytic paper, and cathode foil are sequentially stacked and wound into a columnar core structure. During this process, the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain element A.

[0068] Impregnation: Immerse seed A in anhydrous electrolyte for 10 minutes at a temperature of 50°C to ensure that seed A is fully impregnated with the anhydrous electrolyte and obtain seed B.

[0069] Assembly: Assemble element B with the shell, sealing plug and electronic components to obtain anhydrous aluminum electrolytic capacitor.

[0070] Comparative Example 2

[0071] The difference between Comparative Example 2 and Example 1 is that the polyethylene glycol derivative is replaced by polyethylene glycol (relative molecular weight 200-400) in equal amounts with ethylene glycol-polydimethylsiloxane-polyethylene glycol.

[0072] Comparative Example 3

[0073] The difference between Comparative Example 3 and Example 1 is that the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion was replaced with an anhydrous solvent in equal amounts.

[0074] Comparative Example 4

[0075] The difference between Comparative Example 4 and Example 1 is that vinylene carbonate was replaced in equal amounts with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) dispersion.

[0076] Performance testing

[0077] The capacitors obtained in Examples 1-5 and Comparative Examples 1-4 were subjected to the following performance tests.

[0078] Detection methods / test methods

[0079] Experiment (1)

[0080] The capacitance shall be tested in accordance with GB / T 17702-2021. If the capacitance is greater than 60000μF, it shall be considered as qualified; otherwise, it shall be considered as unqualified.

[0081] Experiment (II)

[0082] Tolerance to extreme environments:

[0083] 1) Place the capacitor in an environment with a temperature of -60℃ and a humidity of 30% for 1000 hours to obtain the sample to be tested, a;

[0084] 2) Place the capacitor in an environment with a temperature of 150℃ and a humidity of 45% for 1000 hours to obtain the sample to be tested, b;

[0085] 3) Place the capacitor in an environment with a temperature of -60℃ and a humidity of 30% for 24 hours, and then place it in an environment with a temperature of -60℃ and a humidity of 30% for 24 hours. Repeat this cycle 20 times to obtain the sample to be tested, c.

[0086] Then, referring to the test method in Experiment (I), the capacitance of samples a, b, and c were tested respectively.

[0087] The remaining capacity of sample a is equal to the capacity of sample a divided by the capacity in experiment (I), and then multiplied by 100%.

[0088] The remaining capacity of sample b is equal to the capacity of sample b divided by the capacity in experiment (I), and then multiplied by 100%.

[0089] The remaining capacity of sample c is equal to the capacity of sample c divided by the capacity in experiment (I), and then multiplied by 100%.

[0090] The above-mentioned remaining capacity rates are classified into different levels:

[0091] S grade: less than 2%; A grade: 2% ≤ capacitance remaining rate < 5%; B grade: 5% ≤ capacitance remaining rate < 10%; C grade: 10% ≤ capacitor remaining rate ≤ 15%; D grade: greater than 15%.

[0092] If sample a has a residual capacity of Grade A (2% ≤ residual capacity < 5%), it indicates that it still maintains good performance at low temperatures over a long period of time (Part 3).

[0093] Soaking time: As the soaking time is extended, the amount of adsorption changes little, indicating that the adsorption rate is good, which in turn indicates that the adsorption effect on anhydrous solvent is good. Calculate the saturation rate, which is equal to the amount of anhydrous electrolyte adsorbed by the seed after soaking for 5 minutes divided by the amount of anhydrous electrolyte adsorbed by the seed after soaking for 10 minutes, and then multiplied by 100.

[0094] The specific details of the above experiments are shown in Table 1;

[0095] Table 1. Experimental data of Examples 1-5 and Comparative Examples 1-4

[0096]

[0097]

[0098] Based on Example 1 and Comparative Example 1 and Table 1, it can be seen that the capacitance of Comparative Example 1 is unqualified, and the high and low temperature resistance of Comparative Example 1 is both at level D. Furthermore, the saturation rate of Comparative Example 1 is lower than that of Example 1. This indicates that the electrolytic paper produced by the process of this application can efficiently adsorb anhydrous electrolyte and reduce its capacitance loss under extreme environments.

[0099] Comparing Example 1 and Comparative Example 2 with Table 1, it can be seen that the high and low temperature resistance of Comparative Example 2 is both at level C, and the saturation rate of Comparative Example 2 is higher than that of Example 1. This indicates that using polyethylene glycol derivatives as electrolytic paper activators has a better activation effect, and combined with the anhydrous electrolyte of this application, it can further improve the capacitor's tolerance to extreme environments and improve the capacitor's durability.

[0100] Comparing Examples 1 and 2 with Table 1, it can be seen that Example 2 uses an activator containing polyethylene glycol derivatives, composed of polyethylene glycol derivatives, methyl acrylate cross-linked polymers, polyamide polyamine epichlorohydrin resin, and diluent (water). Compared with Example 1 (the activator containing polyethylene glycol derivatives is composed of polyethylene glycol derivatives and 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 environments of Example 2 is improved to Grade A (Grade B of Example 1). This indicates that using an activator containing polyethylene glycol derivatives, composed of polyethylene glycol derivatives, methyl acrylate cross-linked polymers, polyamide polyamine epichlorohydrin resin, and diluent (water), achieves better film formation, promotes anhydrous electrolytic adsorption, and reduces the evaporation of anhydrous electrolyte. Combined with the anhydrous electrolyte of this application, it enables the anhydrous aluminum electrolytic capacitor to obtain high stability. When subjected to extreme environments for a long time, it can reduce the qualitative changes of the anhydrous electrolyte, which affect the capacitance and durability.

[0101] Comparing Examples 2-3 and Example 4, it can be seen that when Example 4 uses a polyethylene glycol derivative composed of ethylene glycol-polydimethylsiloxane-polyethylene glycol and polyethylene glycol-polypropylene glycol allyl ether in a weight ratio of 1:1, its tolerance level under extreme environments is improved to level S (one of the two used in Examples 2-3 has a tolerance level of level S). This indicates that the two compounding methods have a synergistic effect, further improving the stability of the anhydrous aluminum electrolytic capacitor. At the same time, the activated layer formed, combined with the anhydrous electrolyte of this application, can achieve better adsorption effect.

[0102] Comparing Examples 4 and 5, it can be seen that the electrolytic paper is made by random weaving of fibers. Combined with the activation and impregnation processes of this application, the final capacitor has a higher content of anhydrous electrolyte, which further improves the capacitance. At the same time, it can reduce capacitance loss when exposed to extreme environments for a long time, improve the stability of the capacitor, and ensure its quality and durability.

[0103] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A manufacturing process for a high-stability anhydrous aluminum electrolytic capacitor, characterized in that, It is obtained by the following method: Electrolytic paper activation: Electrolytic paper is surface activated using an activator containing polyethylene glycol derivatives to remove the solvent and obtain activated electrolytic paper; Winding: The activated electrolytic paper, anode foil, activated electrolytic paper, and cathode foil are sequentially stacked and wound into a columnar core structure. During this process, the aluminum pad lead-out sheet is riveted to the two electrode foils to obtain element A. Impregnation: Immerse element A in anhydrous electrolyte to fully impregnate element A with anhydrous electrolyte to obtain element B; Assembly: Assemble element B with the shell, sealing plug and electronic components to obtain an anhydrous aluminum electrolytic capacitor; The polyethylene glycol derivative in the activator is ethylene glycol-polydimethylsiloxane-polyethylene glycol and / or polyethylene glycol-polypropylene glycol allyl ether; 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.

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

3. The manufacturing process for a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: The activator of the polyethylene glycol derivative is composed of polyethylene glycol derivative, methyl methacrylate crosspolymer, polyamide polyamine epichlorohydrin resin, and diluent.

4. The manufacturing process of a high-stability anhydrous aluminum electrolytic capacitor according to claim 1, characterized in that: 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 alkali solution to adjust the pH value to neutral.

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

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

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

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

9. The manufacturing 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 by random weaving of fibers.

10. A high-stability anhydrous aluminum electrolytic capacitor, comprising a housing, a core, and a sealing plug, wherein the core is housed inside the housing, and the sealing plug seals the opening of the housing and completely seals the core within the housing, characterized in that: The anhydrous aluminum electrolytic capacitor is manufactured using the production process of a high-stability anhydrous aluminum electrolytic capacitor as described in any one of claims 1-9.

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