High-vibration-resistance aluminum electrolytic capacitor and preparation method thereof

Abstract

The invention discloses a high-vibration-resistance aluminum electrolytic capacitor and a preparation method thereof. The method comprises the following steps: S1, riveting: riveting a positive electrode guide chaff and a negative electrode guide chaff on an anode foil and a cathode foil respectively; s2, element winding: intervening electrolytic paper between the anode foil and the cathode foil, and winding to form an element; s3, drying treatment; s4, electrolyte impregnation is carried out; s5, full-glue-pouring type packaging: pouring a first layer of glue into the bottom of the aluminum shell, and preliminarily fixing the element; after the element is installed, a second layer of glue is poured into the top to cover a gap between the cover plate and the aluminum shell; s6, an aging step; the electrolyte in the step S4 comprises the following components in percentage by mass: 40-60% of a solvent, 36-48% of a solute, 3-10% of an additive and 1-2% of a coolant; the solute is prepared from the following components: diammonium hydrogen citrate, ammonium succinate, isopropylamine and isosebacic acid. According to the capacitor prepared by the method, the performance stability and the service life of the capacitor in harsh environments such as high temperature and vibration are obviously improved, and the strict requirements of high-end application scenes are met.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum electrolytic capacitors, and more particularly to a high-vibration-resistant aluminum electrolytic capacitor and a preparation method thereof. Background Art

[0002] With the rapid development of new energy, electric vehicles, and industrial automation, aluminum electrolytic capacitors are facing market demand for high capacity and high reliability. Emerging technologies such as 5G and the Internet of Things are driving the miniaturization and high-density integration of electronic devices. New energy and electric vehicle applications, on the other hand, require capacitors with higher voltages, higher temperature tolerance, and longer lifespans. Furthermore, the trend toward intelligent power tools is placing even higher demands on the electrical performance and electromagnetic compatibility of aluminum electrolytic capacitors, ensuring their efficient interaction with intelligent components such as microcontrollers and sensors.

[0003] Substrate-based self-supporting capacitors, with their advantages of fast charging, long life, high ripple current capability, and high power density, show significant application potential in power tools, inverters, and high-power devices. However, their vibration resistance remains challenging in vibrating environments such as automotive and aerospace applications. Traditional structural designs can easily loosen the connection between the electrode foil and the pins due to vibration, leading to capacitance fluctuations, increased ESR, and other issues, compromising device reliability. Furthermore, the high temperatures experienced by electric vehicles accelerate electrolyte evaporation, further limiting capacitor lifespan.

[0004] The existing technology mainly improves performance by strengthening the structure (such as rubber cushions) and upgrading materials (such as high-purity anode foil and composite electrolyte). For example, the Chinese invention patent application (CN111599597A) provides a highly stable capacitor electrolyte that can increase the service life of capacitors. The electrolyte is made from the following raw materials in parts by weight: 70-75 parts of ethylene glycol, 10-20 parts of propylene glycol, 0.5-1.5 parts of benzyl alcohol, 1-2 parts of ammonium pentaborate, 1-2 parts of citric acid, 1-1.5 parts of borax, 1-2 parts of tributyl phosphate, 1-2 parts of salicylic acid, 1-2 parts of ethyl methyl carbonate, 0.2-0.4 parts of ammonium adipate, 0.2-0.4 parts of adipic acid, 2-4 parts of polyvinyl alcohol, and 1-2 parts of sodium alkylbenzene sulfonate. The electrolyte provided by this invention is applied to aluminum electrolytic capacitors, which is beneficial to improving the high-temperature stability of capacitors, but its vibration protection effect is limited and the cost is relatively high.

[0005] Therefore, developing an aluminum electrolytic capacitor that combines high vibration resistance, high-temperature stability, and intelligent compatibility has become the key to breaking through the industry bottleneck. While the vibration resistance design of current domestic substrate-based self-supporting capacitors can meet general needs, they still suffer from unstable electrical performance in high-end applications, and a better solution is urgently needed. Summary of the Invention

[0006] Based on this, it is necessary to address the above technical problems, and the present invention provides a high vibration-resistant aluminum electrolytic capacitor and a preparation method thereof.

[0007] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing a high vibration-resistant aluminum electrolytic capacitor, which comprises the following steps:

[0008] S1. Riveting: The positive electrode conductive foil strip and the negative electrode conductive foil strip are riveted to the anode foil and cathode foil respectively;

[0009] S2. Element winding: Electrolytic paper is inserted between the anode foil and the cathode foil, and the elements are wound;

[0010] S3, drying treatment;

[0011] S4, electrolyte impregnation;

[0012] S5, Fully potted packaging: The first layer of glue is poured into the bottom of the aluminum shell to initially fix the element; after the element is installed, the second layer of glue is poured into the top to cover the gap between the cover and the aluminum shell;

[0013] S6, aging step;

[0014] The electrolyte in step S4 is composed of the following components by mass percentage: 40-60% solvent, 36-48% solute, 3-10% additive, and 1-2% heat dissipating agent;

[0015] The solute consists of the following components: diammonium hydrogen citrate, ammonium succinate, isopropylamine and isosebacic acid.

[0016] Furthermore, the solvent is composed of the following components by mass percentage: 45-65% of propylene glycol, 24-35% of ethylene glycol monomethyl ether, 8-12% of ammonium sebacate, and 3-8% of benzyl alcohol.

[0017] Furthermore, the solute is composed of the following components by mass percentage: 35-55% diammonium hydrogen citrate, 25-40% ammonium succinate, 10-18% isopropylamine, and 5-10% isosebacic acid.

[0018] Furthermore, the additive is composed of the following components by mass percentage: 30-42% ethylenediaminetetraacetic acid, 25-35% ammonium maleate, 15-20% sorbitol, 5-15% triethanolamine, and 3-8% nitrilotriacetic acid.

[0019] Furthermore, the heat dissipating agent is composed of the following components by mass percentage: 48-60% ammonium adipate, 30-40% ammonium glutarate, and 8-12% glycerol.

[0020] Furthermore, in step S2, the cathode foil is 1.5 to 2.5 mm longer than the anode foil, and the cathode is exposed at the bottom of the core.

[0021] Furthermore, the number of cold welding points in the riveting in step S1 is 20 to 22, with 10 to 11 points symmetrically arranged on each side.

[0022] Furthermore, the thickness of the first layer of glue is 1 to 3 mm; the thickness of the second layer of glue is 2 to 5 mm, and epoxy resin glue is used for glue pouring.

[0023] Furthermore, the tensile strength of the anode foil is 38-42 N / cm.

[0024] A second aspect of the present invention provides a high vibration-resistant aluminum electrolytic capacitor, which is manufactured according to any of the above-mentioned manufacturing methods.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The preparation method of the high-vibration-resistant aluminum electrolytic capacitor provided by the present invention significantly improves the comprehensive performance of the aluminum electrolytic capacitor by optimizing the electrolyte formula and improving the synergistic effect of the packaging structure. The optimized electrolyte adopts a specific ratio of propylene glycol / ethylene glycol monomethyl ether solvent system and diammonium hydrogen citrate / ammonium succinate solute combination, which not only significantly improves the high-temperature stability and conductivity of the electrolyte, but also reduces the incidence of side reactions at operating temperature, so that the capacitor maintains stable electrical characteristics within a wide temperature range. On this basis, the layered glue-filling packaging process effectively enhances the integrity of the internal structure through the dual protection of the bottom fixing layer and the upper reinforcement layer, greatly reducing the risk of pin loosening and internal displacement under vibration conditions. At the same time, increasing the number of cold solder joints and the use of high-strength anode foil further improves the reliability of the electrode connection. These improvements have significantly improved the performance stability and service life of aluminum electrolytic capacitors in harsh environments such as high temperature and vibration, fully meeting the strict requirements of high-end application scenarios for capacitor reliability. DETAILED DESCRIPTION

[0027] In order to help those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0028] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below.

[0029] Example 1

[0030] This embodiment provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which includes the following steps:

[0031] S1. Riveting: The positive electrode conductive foil strip and the negative electrode conductive foil strip are riveted to the anode foil and cathode foil respectively;

[0032] S2. Element winding: Electrolytic paper is inserted between the anode foil and the cathode foil, and the elements are wound;

[0033] S3, drying treatment: drying the wound element at 110-130°C for 1-2 hours;

[0034] S4, electrolyte impregnation: immerse the dried element in the electrolyte and keep it in a vacuum for 30 to 60 minutes;

[0035] S5, Fully potted packaging: The first layer of glue is poured into the bottom of the aluminum shell to initially fix the element; after the element is installed, the second layer of glue is poured into the top to cover the gap between the cover and the aluminum shell;

[0036] S6. Aging: Use intelligent charging equipment to age the products at rated voltage for 10 hours to screen out defective products.

[0037] In step S1, a multi-point cold welding process is used to ensure the reliability of the mechanical connection. The number of cold welding points is 20, specifically distributed as 10 points on each side, with a welding point diameter of 0.5-1.0 mm and a depth of 0.2-0.3 mm. The tensile strength of the anode foil is 40 N / cm. The riveting pressure is 50-80 MPa to ensure close contact between the conductive foil strip and the electrode foil, and the contact resistance is ≤1 mΩ.

[0038] In step S2: the cathode foil is 2 mm longer than the anode foil, and the cathode is exposed at the bottom of the core;

[0039] The electrolyte in step S4 is composed of the following components by mass percentage: 40% solvent, 48% solute, 10% additive, and 2% heat dissipating agent;

[0040] The solvent is composed of the following components by mass percentage: propylene glycol 45%, ethylene glycol monomethyl ether 35%, ammonium sebacate 12%, and benzyl alcohol 8%;

[0041] The solute is composed of the following components by mass percentage: diammonium hydrogen citrate 55%, ammonium succinate 25%, isopropylamine 10%, and isosebacic acid 10%;

[0042] The additive is composed of the following components by mass percentage: 42% of ethylenediaminetetraacetic acid, 25% of ammonium maleate, 20% of sorbitol, 8% of triethanolamine, and 5% of nitrilotriacetic acid;

[0043] The heat dissipating agent is composed of the following components by mass percentage: 60% of ammonium adipate, 32% of ammonium glutarate, and 8% of glycerol.

[0044] In step S5, the first layer of glue uses bisphenol A epoxy resin glue with a thickness of 1.5 mm, a viscosity of 450±50 mPa·s, and a curing condition of 100°C / 0.5 h; the second layer of glue uses biphenyl epoxy resin glue with a thickness of 4 mm, a viscosity of 600±50 mPa·s, completely covering the gap between the cover and the aluminum shell (≤0.1 mm), and a curing condition of 120°C / 0.5 h; the sealing plug is made of butyl rubber.

[0045] Ten aluminum electrolytic capacitors prepared in Example 1 were subjected to performance tests, including: a 105°C high-temperature load test; a vibration test (frequency: 10 Hz - 55 Hz, amplitude: 1.5 mm, direction: X, Y, and Z axes, measured after 2 hours each); a temperature characteristics test (maintained at -25°C for 2 hours); and a temperature rise test (center temperature rise ΔT ≤ 5°C, the applied ripple current is considered to be the maximum ripple current withstand of the capacitor). The test results of Example 1 are shown in Tables 1 and 2 below. The same testing methods were used for performance evaluation of all Examples and Comparative Examples in this embodiment.

[0046] Table 1: Conventional performance test results of the aluminum electrolytic capacitors prepared in Example 1

[0047]

[0048] Table 2: Temperature rise test results of the aluminum electrolytic capacitors prepared in Example 1

[0049]

[0050] Example 2

[0051] This embodiment provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Embodiment 1 in that:

[0052] In step S1, the number of cold weld points is 22, specifically distributed as 11 points symmetrically arranged on each side, with a weld point diameter of 0.5-1.0 mm and a depth of 0.2-0.3 mm; the anode foil tensile strength is 42 N / cm; the riveting pressure is 50-80 MPa, ensuring close contact between the foil guide strip and the electrode foil, and a contact resistance of ≤1 mΩ.

[0053] In step S2: the cathode foil is 2.5 mm longer than the anode foil, and the cathode is exposed at the bottom of the core;

[0054] The electrolyte in step S4 is composed of the following components by mass percentage: 50% solvent, 40% solute, 8% additive, and 2% heat dissipating agent;

[0055] The solvent is composed of the following components by mass percentage: propylene glycol 55%, ethylene glycol monomethyl ether 30%, ammonium sebacate 10%, and benzyl alcohol 5%;

[0056] The solute is composed of the following components in percentage by mass: diammonium hydrogen citrate 43%, ammonium succinate 29%, isopropylamine 18%, isosebacic acid 10%;

[0057] The additive is composed of the following components by mass percentage: 38% of ethylenediaminetetraacetic acid, 32% of ammonium maleate, 18% of sorbitol, 9% of triethanolamine, and 3% of nitrilotriacetic acid;

[0058] The heat dissipating agent is composed of the following components by mass percentage: 50% of ammonium adipate, 40% of ammonium glutarate, and 10% of glycerol.

[0059] In step S5, the thickness of the first layer of glue is 1 mm; the thickness of the second layer of glue is 3 mm.

[0060] The aluminum electrolytic capacitor prepared in Example 2 was subjected to performance testing, and the test results are shown in Tables 3 and 4 below.

[0061] Table 3: Conventional performance test results of the aluminum electrolytic capacitors prepared in Example 2

[0062]

[0063] Table 4: Temperature rise test results of the aluminum electrolytic capacitors prepared in Example 2

[0064]

[0065] Example 3

[0066] This embodiment provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Embodiment 1 in that:

[0067] In step S1, the tensile strength of the anode foil is 38 N / cm, and the riveting pressure is 50-80 MPa, ensuring that the foil guide strip is in close contact with the electrode foil, and the contact resistance is ≤1 mΩ.

[0068] In step S2: the cathode foil is 1.5 mm longer than the anode foil, and the cathode is exposed at the bottom of the core;

[0069] The electrolyte in step S4 is composed of the following components by mass percentage: 52% solvent, 41.5% solute, 5% additive, and 1.5% heat dissipating agent;

[0070] The solvent is composed of the following components by mass percentage: propylene glycol 59%, ethylene glycol monomethyl ether 30%, ammonium sebacate 8%, and benzyl alcohol 3%;

[0071] The solute is composed of the following components in percentage by mass: diammonium hydrogen citrate 44%, ammonium succinate 38%, isopropylamine 13%, isosebacic acid 5%;

[0072] The additive is composed of the following components by mass percentage: 30% of ethylenediaminetetraacetic acid, 35% of ammonium maleate, 15% of sorbitol, 15% of triethanolamine, and 5% of nitrilotriacetic acid;

[0073] The heat dissipating agent is composed of the following components by mass percentage: 48% of ammonium adipate, 40% of ammonium glutarate, and 12% of glycerol.

[0074] In step S5, the thickness of the first layer of glue is 2 mm; the thickness of the second layer of glue is 5 mm.

[0075] The aluminum electrolytic capacitor prepared in Example 3 was subjected to performance testing, and the test results are shown in Tables 5 and 6 below.

[0076] Table 5: Conventional performance test results of the aluminum electrolytic capacitors prepared in Example 3

[0077]

[0078] Table 6: Temperature rise test results of the aluminum electrolytic capacitors prepared in Example 3

[0079]

[0080] Example 4

[0081] This embodiment provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Embodiment 1 in that:

[0082] The electrolyte in step S4 is composed of the following components by mass percentage: 60% solvent, 36% solute, 3% additive, and 1% heat dissipating agent;

[0083] The solvent is composed of the following components by mass percentage: propylene glycol 65%, ethylene glycol monomethyl ether 24%, ammonium sebacate 8%, and benzyl alcohol 3%;

[0084] The solute is composed of the following components by mass percentage: diammonium hydrogen citrate 35%, ammonium succinate 40%, isopropylamine 17%, isosebacic acid 8%;

[0085] The additive is composed of the following components by mass percentage: 34% of ethylenediaminetetraacetic acid, 35% of ammonium maleate, 18% of sorbitol, 5% of triethanolamine, and 8% of nitrilotriacetic acid;

[0086] The heat dissipating agent is composed of the following components by mass percentage: 54% of ammonium adipate, 38% of ammonium glutarate, and 8% of glycerol.

[0087] The aluminum electrolytic capacitor prepared in Example 4 was subjected to performance testing, and the test results are shown in Tables 7 and 8 below.

[0088] Table 7: Conventional performance test results of the aluminum electrolytic capacitors prepared in Example 4

[0089]

[0090] Table 8: Temperature rise test results of the aluminum electrolytic capacitors prepared in Example 4

[0091]

[0092] Comparative Example 1

[0093] This comparative example provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Example 1 only in that the solvent does not contain ammonium sebacate.

[0094] The aluminum electrolytic capacitor prepared in Comparative Example 1 was subjected to performance tests, and the test results are shown in the following table.

[0095] Table 9: Conventional performance test results of the aluminum electrolytic capacitor prepared in Comparative Example 1

[0096]

[0097] Table 10: Temperature rise test results of the aluminum electrolytic capacitor prepared in Comparative Example 1

[0098]

[0099] The key difference between this comparative example and Example 1 is that ammonium sebacate is not added to the solvent system. The test results show that the lack of ammonium sebacate will cause the performance stability of the aluminum electrolytic capacitor under vibration and high temperature conditions to be significantly reduced. Specifically, in the 105°C high temperature load test, the capacity attenuation rate of Comparative Example 1 reached -22.06%, which is 2.2 times that of Example 1 (-10.14%), and the aluminum shell bulging phenomenon appeared in all cases after the test; after the vibration test, the leakage current (LC) fluctuation amplitude of Comparative Example 1 was as high as 102.13%, while that of Example 1 was only 3.80%, and the center temperature rise of Comparative Example 1 after the temperature rise test was 6.56°C, exceeding the qualified standard of 5°C. This is mainly because ammonium sebacate has unique chemical stability and solvent properties: its molecular structure can remain stable over a wide temperature and pH range, and is not easily decomposed or oxidized, thereby ensuring the long-term stability of the electrolyte system. As a solvent component, ammonium sebacate forms a synergistic effect with propylene glycol and ethylene glycol monomethyl ether. By adjusting the ionic strength and viscosity balance of the solvent system, it promotes the full dissolution of the solute while preventing excessive flow or stratification of the electrolyte. This synergistic effect ensures that the electrolyte remains uniform and stable under harsh conditions such as vibration and high temperature, significantly improving the capacitor's vibration resistance and high-temperature reliability.

[0100] Comparative Example 2

[0101] This comparative example provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Example 1 only in that ammonium adipate is used in place of diammonium hydrogen citrate and ammonium succinate in the solute.

[0102] The aluminum electrolytic capacitor prepared in Comparative Example 2 was subjected to performance tests, and the test results are shown in Tables 11 and 12 below.

[0103] Table 11: Conventional performance test results of aluminum electrolytic capacitors prepared in Comparative Example 2

[0104]

[0105] Table 12: Temperature rise test results of aluminum electrolytic capacitors prepared in Comparative Example 2

[0106]

[0107] This comparative example differs from Example 1 in that ammonium adipate replaces diammonium citrate and ammonium succinate in the solute. Test results show that this change significantly reduces the performance stability of the capacitor under high temperature and vibration conditions. Samples 4 and 6 experienced extreme failure due to aluminum shell bulging or leakage after the 105°C high-temperature load and vibration tests, respectively. These data are not included in the performance statistics. In the 105°C high-temperature load test, the capacity decay rate of Comparative Example 2 reached a high of -25.83%. After the temperature characteristics test, the low-temperature impedance (Z) of Comparative Example 2 increased by 307.81%, a significant improvement over the 170.30% of Example 1. After the temperature rise test, the center temperature of Comparative Example 2 rose by 6.44°C, exceeding the qualified standard. This is primarily due to the unique synergistic effect of diammonium hydrogen citrate and ammonium succinate: first, diammonium hydrogen citrate and ammonium succinate dissociate synergistically in solution to produce more freely mobile ions, significantly improving the solution's conductivity. Second, their molecular structures synergistically regulate the solution's viscosity when the temperature changes, maintaining stable ion mobility at high temperatures. Most importantly, the steric hindrance effects of the two solute molecules overlap, and the specific spatial arrangement of their carboxyl groups effectively hinders the binding of water molecules to solute ions, significantly inhibiting hydration. In contrast, single ammonium adipate cannot achieve this multi-layered synergistic protection mechanism, resulting in a significant decrease in capacitor performance.

[0108] Comparative Example 3

[0109] This comparative example provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Example 1 only in that the solute does not contain isopropylamine.

[0110] The aluminum electrolytic capacitor prepared in Comparative Example 3 was subjected to performance testing, and the test results are shown in Tables 13 and 14 below.

[0111] Table 13: Conventional performance test results of aluminum electrolytic capacitors prepared in Comparative Example 3

[0112]

[0113] Table 14: Temperature rise test results of aluminum electrolytic capacitors prepared in Comparative Example 3

[0114]

[0115] This comparative example differs from Example 1 in that isopropylamine is not added to the solute. Test results show that the absence of isopropylamine significantly increases hydrogen evolution under high-temperature operating conditions and significantly decreases electrolyte stability. Specifically, in a 105°C high-temperature load test, the DF of Comparative Example 3 increased by 395.38%, 3.6 times the 110.96% of Example 1. After the temperature characteristics test, the low-temperature impedance (Z) of Comparative Example 3 increased by 253.76%, a 49% increase over the 170.30% of Example 1. On the one hand, isopropylamine molecules can embed into the pores of the passivation film formed by isosebacic acid, enhancing the film's density through steric hindrance and effectively blocking the penetration of moisture and active ions. On the other hand, isopropylamine and isosebacic acid synergistically form a dynamic acid-base buffer system. When acidic byproducts appear in the electrolyte, the basic groups of isopropylamine can promptly neutralize them, while isosebacic acid maintains overall pH stability. This dual regulatory mechanism significantly inhibits side reactions such as hydrogen evolution. From the test data of Example 1, it can be seen that the introduction of isopropylamine significantly reduces the performance attenuation rate of the capacitor after high-temperature aging, fully demonstrating its important role in extending the life of the capacitor.

[0116] Comparative Example 4

[0117] This comparative example provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Example 1 only in that ammonium maleate and nitrilotriacetic acid are not added as additives.

[0118] The aluminum electrolytic capacitor prepared in Comparative 4 was subjected to performance testing, and the test results are shown in Tables 15 and 16 below.

[0119] Table 15: Conventional performance test results of aluminum electrolytic capacitors prepared in Comparative Example 4

[0120]

[0121] Table 16: Temperature rise test results of the aluminum electrolytic capacitor prepared in Comparative Example 4

[0122]

[0123] This comparative example differs from Example 1 in that ammonium maleate and nitrilotriacetic acid are not added to the additives. Test results show that this change leads to a significant decrease in the performance stability of the capacitor under high-voltage and high-temperature operating conditions. Specifically, in the high-temperature load test, the capacity decay rate of Comparative Example 4 reached -23.23%, worse than the -10.14% of Example 1; in the vibration test, the leakage current (LC) fluctuation rate of Comparative Example 4 was as high as 50.91%, exceeding the 3.80% of Example 1. In the temperature characteristics test, the low-temperature impedance (Z) of Comparative Example 4 increased by 229.55%, compared to 170.30% of Example 1. This is mainly because ammonium maleate and nitrilotriacetic acid have a unique synergistic protection mechanism: they can selectively adsorb on the surface of the oxide film, forming a dense composite protective layer, effectively blocking the penetration of corrosive substances in the electrolyte, and significantly reducing the expansion and dissolution of the oxide film pores. At the same time, the active groups in the molecules of these two additives can specifically bind to the active sites on the electrode surface, reducing the electrode surface activity through chemical bonding, thereby reducing the occurrence of side reactions. According to the test data of Example 1, this dual protection mechanism not only enhances the stability of the oxide film, but also significantly improves the passivation effect of the electrode-electrolyte interface, enabling the capacitor to maintain excellent performance stability under high voltage and high and low temperature conditions.

[0124] Comparative Example 5

[0125] This comparative example provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor, which differs from Example 1 only in that ammonium adipate and ammonium glutarate are not added to the heat dissipation agent.

[0126] The aluminum electrolytic capacitor prepared in Comparative Example 5 was subjected to performance testing, and the test results are shown in Tables 17 and 18 below.

[0127] Table 17: Conventional performance test results of the aluminum electrolytic capacitor prepared in Comparative Example 5

[0128]

[0129] Table 18: Temperature rise test results of the aluminum electrolytic capacitor prepared in Comparative Example 5

[0130]

[0131] This comparative example differs from Example 1 in that ammonium adipate and ammonium glutarate are omitted from the heat dissipation agent. Test results show that this change significantly exacerbates the capacitor's temperature rise under high-temperature operating conditions and significantly reduces heat dissipation efficiency. Sample 2 in Comparative Example 5 completely failed after a 105°C high-temperature load test due to the aluminum shell opening; this data is not included in performance statistics. The overall capacity decay rate was -28.28%, a significant increase from the -10.14% in Example 1. During the vibration test, the ESR change rate of Comparative Example 5 was 48.73%, far exceeding the 0.77% in Example 1. During the temperature characteristics test, the low-temperature impedance (Z) of Comparative Example 5 increased by 292.18%, also exceeding the 170.30% in Example 1. After the temperature rise test, the center temperature rose by 10.76°C, significantly exceeding the 5°C qualification standard. This is due to the synergistic effect of ammonium adipate and ammonium glutarate in the heat dissipation agent: first, the glutarate ions, thanks to their high mobility, rapidly transfer heat; second, the ammonium adipate ions balance the ion distribution, ensuring uniform heat conduction throughout the electrolyte system and enhancing the electrolyte's heat dissipation performance. Together with glycerol, these two ions work together to create an electrolyte system that effectively dissipates heat. In Comparative Example 5, the lack of these two ion-conducting media significantly reduces the electrolyte's fluidity and thermal diffusion capacity, leading to the formation of localized hot spots, which severely impacts the capacitor's temperature stability and operating life.

[0132] Comparative Example 6

[0133] This comparative example provides a method for preparing a highly vibration-resistant aluminum electrolytic capacitor, which differs from Example 1 in that: in step S1, the number of cold solder joints is 12, specifically distributed as symmetrical arrangement of 6 points on each side; and the tensile strength of the anode foil is 30 N / cm.

[0134] The aluminum electrolytic capacitor prepared in Comparative Example 6 was subjected to performance testing, and the test results are shown in Tables 19 and 20 below.

[0135] Table 19: Conventional performance test results of aluminum electrolytic capacitors prepared in Comparative Example 6

[0136]

[0137] Table 20: Temperature rise test results of aluminum electrolytic capacitors prepared in Comparative Example 6

[0138]

[0139] Comparing the results of Example 1 and Comparative Example 6, the leakage current (LC) increased by 121.04% after the vibration test, which is a larger increase than the 3.80% increase in Example 1. After the vibration test of Comparative Example 6, Samples 4 and 9 also experienced failure phenomena such as broken positive or negative electrode guide pins. Since the anode foil of Comparative Example 6 has a lower tensile strength and fewer cold welds, the electrode structure is more easily deformed under mechanical vibration during the vibration test. At the same time, the lack of cold welds also leads to increased contact resistance, causing additional heat and reducing capacitor efficiency.

[0140] Comparative Example 7

[0141] This comparative example provides a method for preparing a high-vibration-resistant aluminum electrolytic capacitor. The only difference from Example 1 is that in step S5, conventional single-layer glue potting using bisphenol A epoxy resin glue is used. After the element is placed in the aluminum shell, a sufficient amount of bisphenol A epoxy resin glue is directly injected at one time. The glue liquid is allowed to flow naturally to fill the internal space. After curing, a single-layer packaging structure is formed. The glue layer thickness is 4 mm.

[0142] The aluminum electrolytic capacitor prepared in Comparative Example 7 was subjected to performance testing, and the test results are shown in Tables 21 and 22 below.

[0143] Table 21: Conventional performance test results of the aluminum electrolytic capacitor prepared in Comparative Example 7

[0144]

[0145] Table 22: Temperature rise test results of the aluminum electrolytic capacitor prepared in Comparative Example 7

[0146]

[0147] The test results of Comparative Example 1 and Comparative Example 7 show that Example 1 is significantly better than Comparative Example 7 with traditional single-layer glue potting in terms of vibration resistance. The leakage current (LC) of Comparative Example 7 increased by 114.36% after the vibration test, and Sample 6 even failed due to a short circuit, which was mainly due to the inherent defects of the single-layer glue potting process. The layered glue potting has a double-layer structure with bottom bonding and top reinforcement filling, which effectively covers the key gap between the cover plate and the aluminum shell, so that the internal components form a more integrated support system. In the vibration test, Comparative Example 7 had loose pins and unstable electrical connections due to local loose fixation due to the difficulty of completely filling the complex internal space with a single-layer glue potting; while the layered glue potting structure of Example 1 significantly improved the overall mechanical strength, and the various components deformed synergistically during vibration, avoiding failure caused by stress concentration, verifying the key role of layered glue potting in improving the vibration resistance reliability of capacitors.

[0148] Obviously, the embodiments described above are only a part of the embodiments of the present application, rather than all the embodiments, and do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned specific embodiments, or to make equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the present application specification, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present application.

Claims

1. A method for preparing a high vibration-resistant aluminum electrolytic capacitor, characterized in that: The following steps are involved: S1. Riveting: The positive electrode conductive foil strip and the negative electrode conductive foil strip are riveted to the anode foil and cathode foil respectively; S2. Element winding: Electrolytic paper is inserted between the anode foil and the cathode foil, and the elements are wound; S3, drying treatment; S4, electrolyte impregnation; S5, Fully potted packaging: The first layer of glue is poured into the bottom of the aluminum shell to initially fix the element; after the element is installed, the second layer of glue is poured into the top to cover the gap between the cover and the aluminum shell; S6, aging step; The electrolyte in step S4 is composed of the following components by mass percentage: 40-60% solvent, 36-48% solute, 3-10% additive, and 1-2% heat dissipating agent; The solute consists of the following components: diammonium hydrogen citrate, ammonium succinate, isopropylamine and isosebacic acid.

2. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 1, wherein: The solvent is composed of the following components by mass percentage: 45-65% of propylene glycol, 24-35% of ethylene glycol monomethyl ether, 8-12% of ammonium sebacate, and 3-8% of benzyl alcohol.

3. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 2, wherein: The solute is composed of the following components by mass percentage: 35-55% of diammonium hydrogen citrate, 25-40% of ammonium succinate, 10-18% of isopropylamine, and 5-10% of isosebacic acid.

4. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 3, wherein: The additive consists of the following components by mass percentage: 30-42% of ethylenediaminetetraacetic acid, 25-35% of ammonium maleate, 15-20% of sorbitol, 5-15% of triethanolamine, and 3-8% of nitrilotriacetic acid.

5. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 4, wherein: The heat dissipating agent is composed of the following components by mass percentage: 48-60% of ammonium adipate, 30-40% of ammonium glutarate, and 8-12% of glycerol.

6. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 1, wherein: In step S2, the cathode foil is 1.5 to 2.5 mm longer than the anode foil, and the cathode is exposed at the bottom of the core.

7. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 6, wherein: The number of cold welding points in the riveting in step S1 is 20 to 22, with 10 to 11 points symmetrically arranged on each side.

8. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 7, wherein: The thickness of the first layer of glue is 1-3 mm; the thickness of the second layer of glue is 2-5 mm, and epoxy resin glue is used for glue pouring.

9. The method for preparing a high vibration-resistant aluminum electrolytic capacitor according to claim 8, wherein: The tensile strength of the anode foil is 38-42 N / cm.

10. A highly vibration-resistant aluminum electrolytic capacitor prepared by the method according to any one of claims 1 to 9.

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