High-temperature-resistant aluminum electrolytic capacitor and preparation process thereof

Abstract

The invention relates to the field of aluminum electrolytic capacitors, and discloses a high-temperature-resistant aluminum electrolytic capacitor and a preparation process thereof. The high-temperature-resistant aluminum electrolytic capacitor comprises a shell, a capacitor core and a rubber plug, the capacitor core is contained in the shell, the rubber plug is used for sealing the shell, the capacitor core is prepared by soaking a core body in a high-temperature-resistant electrolyte, the core body is formed by winding an anode aluminum foil, a cathode aluminum foil and electrolytic paper, and the electrolytic paper is arranged between the anode aluminum foil and the cathode aluminum foil; the high-temperature-resistant electrolyte is prepared from the following raw materials in percentage by weight: 55-64% of a solvent, 20-30% of a solute, 4-8% of a stabilizer, 3-4.5% of a glycidyl ester substance, 2-4% of a sparking voltage boosting agent, 1.5-3.5% of a corrosion inhibitor and 0.5-1% of a hydrogen elimination agent. The aluminum electrolytic capacitor provided by the invention has good high temperature resistance, good charge storage and release stability, and good reliability and stability when used in a high temperature environment for a long time.

Description

Technical Field

[0001] The present application relates to the field of aluminum electrolytic capacitors, and more specifically, to a high-temperature resistant aluminum electrolytic capacitor and a preparation process thereof. Background Art

[0002] An aluminum electrolytic capacitor is a capacitor with positive and negative electrodes. Its basic structure consists of an anode aluminum foil, a cathode aluminum foil, and a layer of electrolyte-soaked backing paper sandwiched between them, wrapped in an overlapping pattern. The capacitor is then sealed with an aluminum shell and a plastic cover. After the electrodes are immersed in the electrolyte, electrolysis forms an extremely thin aluminum oxide film on the surface of the positive electrode. This film has a high dielectric constant and is capable of storing charge. High-efficiency electrolytic capacitors offer the advantages of large capacity and low price. They are widely used in power filter circuits, switching power supplies, automotive applications, LED lighting, industrial frequency conversion, and new energy, providing a key guarantee for the high performance and long life of electronic equipment.

[0003] The electrolyte plays a vital role in aluminum electrolytic capacitors. The electrolyte can maintain the capacitance and repair the aluminum oxide film, thereby ensuring the charge storage and release stability of the aluminum electrolytic capacitor. The electrolyte in the existing technology generally contains solvents such as ethylene glycol and propylene glycol, and the solute is mainly borate or its derivatives. At the same time, some additives such as benzotriazole and trimesic acid may be added to improve performance. The boiling point of the solvent is relatively low, which makes the electrolyte prone to volatilization and aging problems in high temperature environments, affecting the stability and conductivity of the electrolyte. The solute has limited thermal stability and is easily decomposed under high temperature conditions, which reduces the performance of the electrolyte and affects the charge storage and release stability of the aluminum electrolytic capacitor. Although additives can improve performance, their effect will gradually weaken under high temperature conditions, and they cannot effectively solve the problem of performance degradation of the electrolyte under high temperature conditions.

[0004] With the advancement of technology and the diversification of application environments, the requirements for aluminum electrolytic capacitors are becoming increasingly stringent, especially in new energy drive power supplies. New energy drive power supplies can cause temperatures to rise continuously during long-term operation. When aluminum electrolytic capacitors operate in high-temperature environments for long periods of time, the electrolyte is more susceptible to volatilization and aging, which in turn leads to a decrease in capacitor performance and eventual failure, affecting the stability and reliability of the entire circuit. Summary of the Invention

[0005] In order to solve the problem that the electrolyte used in aluminum electrolytic capacitors is prone to volatilization and aging when operated in a long-term high-temperature environment, which reduces the stability of the aluminum electrolytic capacitor, the present application provides a high-temperature resistant aluminum electrolytic capacitor and a preparation process thereof.

[0006] In a first aspect, the present application provides a high-temperature resistant aluminum electrolytic capacitor, which adopts the following technical solution: A high-temperature resistant aluminum electrolytic capacitor comprises a shell, a capacitor core, and a rubber plug. The capacitor core is accommodated in the shell, and the rubber plug is used to seal the shell. The capacitor core is made by soaking a core body in a high-temperature resistant electrolyte. The core body is formed by winding an anode aluminum foil, a cathode aluminum foil, and electrolytic paper, and the electrolytic paper is arranged between the anode aluminum foil and the cathode aluminum foil. The high-temperature resistant electrolyte is made from the following raw materials in weight percentage: 55-64% solvent, 20-30% solute, 4-8% stabilizer, 3-4.5% glycidyl ester substance, 2-4% flash voltage enhancer, 1.5-3.5% corrosion inhibitor, and 0.5-1% hydrogen scavenger.

[0007] By adopting this technical solution, the high-temperature-resistant aluminum electrolytic capacitor has a rational structural design. The capacitor core is housed in a housing and sealed with a rubber plug, which prevents external interference with the capacitor core and improves the stability and sealing of the overall structure. The capacitor core is made of a core body soaked in a high-temperature-resistant electrolyte, which enables the electrolyte to fully function and ensures effective storage and release of charge.

[0008] In terms of high-temperature resistant electrolytes, solvents account for 55-65%, providing a good dissolution environment for other components and ensuring uniform dispersion of each component; solutes account for 20-30%, participating in charge transfer and maintaining the conductivity of the electrolyte; stabilizers account for 4-8%, which can enhance the thermal stability of the electrolyte, prevent it from decomposing at high temperatures, and ensure stable electrolyte performance; glycidyl esters account for 3-4.5%, which can improve the chemical stability of the electrolyte and enhance its ability to resist chemical reactions in high-temperature environments; flash voltage enhancers account for 2-4%, which can increase the flash voltage of the electrolyte, reduce the risk of breakdown, and improve safety; corrosion inhibitors account for 1.5-3.5%, which can inhibit the corrosion of metal parts and extend the service life of capacitors; dehydrogenators account for 0.5-1%, which can eliminate hydrogen and prevent safety hazards caused by hydrogen accumulation.

[0009] There is a synergistic effect between stabilizers, glycidyl esters, and flash voltage boosters. Stabilizers improve the thermal stability of the electrolyte, enabling glycidyl esters and flash voltage boosters to function better at high temperatures. The enhanced chemical stability of glycidyl esters helps stabilize the stabilizer while also assisting the flash voltage booster in increasing the flash voltage. The reduced breakdown risk of the flash voltage booster creates a more stable operating environment for the stabilizer and glycidyl esters, further enhancing their effectiveness.

[0010] In summary, the aluminum electrolytic capacitor of the present application has good high temperature resistance. When used in a high temperature environment for a long time, the electrolyte can maintain stable performance, and the charge storage and release are stable, effectively avoiding the degradation and failure of capacitor performance caused by problems such as electrolyte volatilization, aging and performance degradation, and has good reliability and stability.

[0011] Preferably, the solvent is composed of ethylene glycol, γ-caprolactone, ethylene glycol monobutyl ether and diethylene glycol in a weight ratio of (3-4):(1-2):(1.5-2.5):1.

[0012] By adopting the above technical solution, ethylene glycol, γ-caprolactone, ethylene glycol monobutyl ether and diethylene glycol are compounded in an optimal weight ratio as a solvent in the high-temperature resistant electrolyte, which can improve the fluidity and electrolytic stability of the high-temperature resistant electrolyte, effectively reduce the volatility of the high-temperature resistant electrolyte when operating in a high-temperature environment, and make the performance of the high-temperature resistant aluminum electrolytic capacitor more stable.

[0013] Preferably, the solute is a combination of at least two of ammonium hydrogen phosphate, ammonium sebacate, ammonium azelate, and ammonium adipate.

[0014] By adopting the above technical solution, a combination of at least two of ammonium hydrogen phosphate, ammonium sebacate, ammonium azelaic acid, and ammonium adipate is used as the solutes of the high-temperature resistant electrolyte. These solutes, together with components such as a solvent, a stabilizer, a glycidyl ester, a flash voltage enhancer, a corrosion inhibitor, and a hydrogen scavenger, constitute the electrolyte system. These solutes can provide ions in the electrolyte, participate in the electrolysis reaction, form a stable aluminum oxide film on the surface of the anode aluminum foil, maintain the conductivity of the electrolyte, and thereby ensure the charge storage and release stability of the aluminum electrolytic capacitor in a high-temperature environment. This ensures that the aluminum electrolytic capacitor has good high-temperature resistance and good reliability and stability in long-term use in high-temperature environments.

[0015] Preferably, the stabilizer is composed of laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a weight ratio of 1:(0.2-0.4).

[0016] By adopting the above technical solution, the stability of the electrolyte can be improved by using laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in an optimal weight ratio as stabilizers. Laurylamine dipropylene diamine has good film-forming properties and chemical stability. It can form a protective film on the surface of the electrode to prevent side reactions between the electrode and the electrolyte and reduce the volatilization and aging of the electrolyte at high temperatures. 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate helps to improve the overall heat resistance of the electrolyte and prevent the solute and solvent system from decomposing at high temperatures. The synergistic effect of the two enables the electrolyte to maintain good stability and conductivity in a high-temperature environment, thereby making the aluminum electrolytic capacitor more reliable and stable when used in a high-temperature environment for a long time.

[0017] Preferably, the glycidyl ester substance consists of diglycidyl 1,2-cyclohexanedicarboxylate and diglycidyl tetrahydrophthalate in a weight ratio of (2-4):1.

[0018] By adopting the above technical solution, the glycidyl ester substances composed of diglycidyl 1,2-cyclohexanedicarboxylate and diglycidyl tetrahydrophthalate in a specific weight ratio can act synergistically in the electrolyte system, undergo physical adsorption on the surface of the anodic oxide film, and form a denser and more uniform protective layer, thereby improving the corrosion resistance and anti-puncture ability of the oxide film, making the aluminum electrolytic capacitor more resistant to high temperatures, and improving the reliability and stability of long-term use in high-temperature environments, thereby extending the service life of the capacitor.

[0019] Preferably, the flash voltage enhancer is prepared by kneading nano-silicon dioxide and 2-octenylsuccinic anhydride in a weight ratio of 10:(0.4-0.6).

[0020] By adopting the above technical solution, a flash voltage enhancer is prepared by kneading nano-silica and 2-octenylsuccinic anhydride in an optimal weight ratio, which can play a good synergistic role with stabilizers and glycidyl ester substances, so that aluminum electrolytic capacitors can have better high temperature resistance, can ensure the stability of charge storage and release, and are less likely to have discharge flashover on the surface of the anodized film, thereby enhancing the stability and reliability of the capacitor under high voltage.

[0021] Preferably, the corrosion inhibitor is any one or a combination of a phosphate corrosion inhibitor, a benzotriazole corrosion inhibitor, and a quaternary ammonium salt corrosion inhibitor.

[0022] By adopting the above technical solution, the corrosion inhibitor can form a protective film on the surface of the anode aluminum foil, effectively inhibiting the corrosion of the anode aluminum foil and preventing the degradation of capacitance performance caused by corrosion. Moreover, they can still maintain a good corrosion inhibition effect in high temperature environments, which can improve the stability and conductivity of the electrolyte, thereby further improving the high temperature resistance of aluminum electrolytic capacitors and ensuring their reliability and stability when used in long-term high temperature environments.

[0023] Preferably, the hydrogen scavenger is any one or a combination of p-nitrobenzoic acid, p-nitroanisole, p-nitrobenzyl alcohol, and p-nitrophenol.

[0024] By adopting this technical solution, hydrogen is generated at the cathode during the electrolysis process. Excessive hydrogen can cause the internal pressure of the capacitor to rise, which can, in severe cases, cause bulging or even open the explosion-proof valve. The aforementioned hydrogen scavenger reacts with hydrogen ions to reduce hydrogen evolution, thereby lowering the pressure within the high-temperature resistant electrolyte system, avoiding safety issues caused by excessive internal pressure and extending the capacitor's service life.

[0025] In a second aspect, the present application provides a process for preparing a high-temperature resistant aluminum electrolytic capacitor, which adopts the following technical solution: A process for preparing a high-temperature resistant aluminum electrolytic capacitor comprises the following steps: S1, stacking the anode aluminum foil, electrolytic paper and cathode aluminum foil in sequence from the inside to the outside and winding them to form a core; S2, immersing the core in a high temperature resistant electrolyte to obtain a capacitor core; S3. Place the capacitor core in the shell and seal it with a rubber plug to obtain a high-temperature resistant electrolytic capacitor.

[0026] By adopting the above technical solution, in step S1, the anode aluminum foil, electrolytic paper and cathode aluminum foil are stacked and wound in sequence from the inside to the outside to form a core body. The reasonable stacking and winding method ensures that the components are tightly fitted and stably positioned, providing a good physical structure foundation for the subsequent storage and release of electrolyte and charge. In step S2, the core body is immersed in a high-temperature resistant electrolyte to obtain a capacitor core, so that the high-temperature resistant electrolyte fully infiltrates the capacitor core. In step S3, the capacitor core is placed in a shell and sealed with a rubber plug to obtain a high-temperature resistant electrolytic capacitor. The sealing measures prevent the entry of external impurities and the leakage of internal electrolyte, thereby ensuring the overall stability of the capacitor. The steps are coordinated, so that the finally obtained high-temperature resistant aluminum electrolytic capacitor has good high-temperature resistance and good reliability and stability when used in a high-temperature environment for a long time.

[0027] Preferably, the immersion in step S2 is pressurized immersion, the pressurized pressure is 0.2-0.4 MPa, the number of immersions is 3-5 times, and the immersion time each time is 3-5 minutes.

[0028] By adopting the above technical solution, when preparing aluminum electrolytic capacitors, the optimal pressurized immersion conditions of 0.2-0.4 MPa, 3-5 immersion times, and 3-5 minutes of immersion time each time are adopted. This allows the core to more fully absorb the high-temperature resistant electrolyte and penetrate into the space between the anode aluminum foil, cathode aluminum foil, and electrolytic paper, thereby improving the reliability and stability of the aluminum electrolytic capacitor.

[0029] In summary, this application includes at least one of the following beneficial technical effects: 1. The high-temperature resistant aluminum electrolytic capacitor of the present application has a capacitor core made of a core soaked in a high-temperature resistant electrolyte made from raw materials in a specific ratio. The high-temperature resistant electrolyte is prepared from a solvent, a solute, a stabilizer, a glycidyl ester substance, a flash voltage enhancer, a corrosion inhibitor and a hydrogen scavenger. The aluminum electrolytic capacitor of the present application has good high-temperature resistance. When used in a high-temperature environment for a long time, the electrolyte can maintain stable performance, and the charge storage and release are stable, effectively avoiding the degradation and failure of the capacitor performance caused by problems such as electrolyte volatilization, aging and performance degradation, and has good reliability and stability.

[0030] 2. The stabilizer is composed of laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, which can solve the problems of volatility, aging and solute decomposition of existing electrolytes under high temperature environments, and improve the stability and conductivity of the electrolyte.

[0031] 3. Glycidyl esters are composed of diglycidyl 1,2-cyclohexanedicarboxylate and diglycidyl tetrahydrophthalate, which help to further improve the performance of aluminum electrolytic capacitors in high temperature environments.

[0032] 4. The flash voltage enhancer is made by kneading nano-silica and 2-octenylsuccinic anhydride, which can make the aluminum electrolytic capacitor have better high temperature resistance, ensure the stability of charge storage and release, and make the surface of the anodic oxide film less prone to discharge flashover, thereby enhancing the stability and reliability of the capacitor under high voltage.

[0033] 5. The preparation process of the present application includes winding an anode aluminum foil, electrolytic paper and a cathode aluminum foil to form a core, then pressurizing and immersing the core in a high-temperature resistant electrolyte, and finally sealing it. The obtained aluminum electrolytic capacitor has good charge storage and release stability, reliability and stability when used in a high-temperature environment for a long time. DETAILED DESCRIPTION

[0034] The present application is further described in detail below with reference to the embodiments.

[0035] The following are the sources and specifications of some raw materials of this application. The raw materials used in the preparation examples and examples of this application can be obtained from commercial sources, including but not limited to the following models and manufacturers. Raw materials with equivalent performance can be used: 1. Laurylamine dipropylene diamine: CAS No. 2372-82-9, content 99%; 2. Nano-silicon dioxide: particle size 50-100nm; 3. 2-Octenylsuccinic anhydride: CAS No. 26680-54-6, content 99%.

[0036] Preparation example of high temperature resistant electrolyte Preparation Example 1 Preparation Example 1 discloses a high-temperature resistant electrolyte, which is prepared by the following steps: heating 5.5 kg of solvent, 0.8 kg of stabilizer, and 0.3 kg of 1,2-cyclohexanedicarboxylic acid diglycidyl ester as a glycidyl ester substance to 70° C., stirring evenly, adding 3 kg of solute and 0.2 kg of flash voltage booster, heating to 90° C., stirring evenly, then cooling to 60° C., adding 0.15 kg of corrosion inhibitor and 0.05 kg of p-nitroanisole as a hydrogen scavenger, stirring evenly, to prepare a high-temperature resistant electrolyte; The solvent is composed of ethylene glycol, γ-caprolactone, ethylene glycol monobutyl ether, and diethylene glycol in a ratio of 3:2:1.5:1; the stabilizer is composed of dibutyl phosphate and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a ratio of 1:0.2; the solute is composed of ammonium sebacate, ammonium oxalate, and ammonium hydrogen phosphate in a weight ratio of 2:1:0.5; the flash voltage enhancer is prepared by kneading 50 nm nano-silica and polyvinyl alcohol in a weight ratio of 10:0.4 at a temperature of 100°C; and the corrosion inhibitor is composed of polyol phosphate and benzotriazole in a weight ratio of 1:2; The polyvinyl alcohol is PVA2399, and the polyol phosphate is Jiyesheng PAPE, with a content of 50%.

[0037] Preparation Example 2-3 The difference between Preparation Example 2-3 and Preparation Example 1 is that the amount of raw materials used and the preparation conditions are different. Please refer to Table 1 below for details.

[0038] Table 1 Parameters of Preparation Examples 1-3 Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the stabilizer consists of laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a weight ratio of 1:0.2, and the rest is the same as Preparation Example 1.

[0039] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that the stabilizer consists of laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a weight ratio of 1:0.4, and the rest is the same as Preparation Example 1.

[0040] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 4 is that the glycidyl ester substance consists of diglycidyl 1,2-cyclohexanedicarboxylate and diglycidyl tetrahydrophthalate in a weight ratio of 2:1, and the rest is the same as Preparation Example 4.

[0041] Preparation Example 7 The difference between Preparation Example 7 and Preparation Example 4 is that the glycidyl ester substance consists of diglycidyl 1,2-cyclohexanedicarboxylate and diglycidyl tetrahydrophthalate in a weight ratio of 4:1, and the rest is the same as Preparation Example 4.

[0042] Preparation Example 8 The difference between Preparation Example 8 and Preparation Example 7 is that the flash voltage enhancer is prepared by kneading 50 nm nano-silica and 2-octenylsuccinic anhydride in a weight ratio of 10:0.4 at a temperature of 100° C., and the rest is the same as Preparation Example 7.

[0043] Preparation Example 9 The difference between Preparation Example 9 and Preparation Example 7 is that the flash voltage enhancer is prepared by kneading 50 nm nano-silica and 2-octenylsuccinic anhydride in a weight ratio of 10:0.6 at a temperature of 100°C. The other conditions are the same as Preparation Example 7.

[0044] Preparation Comparative Example 1 The difference between Preparation Comparative Example 1 and Preparation Example 1 is that an equal amount of glycidyl ester substances is replaced by stabilizers, and the other steps are the same as Preparation Example 1.

[0045] Preparation Comparative Example 2 The difference between Preparation Comparative Example 2 and Preparation Example 1 is that the stabilizer is replaced with an equal amount of a flash voltage enhancer, and the rest is the same as Preparation Example 1. Example

[0046] Example 1 Example 1 discloses a high-temperature resistant aluminum electrolytic capacitor, including a shell, a capacitor core and a rubber plug. The capacitor core is accommodated in the shell, and the rubber plug is used to seal the shell. The rubber plug is made of butyl fluororubber material, which has good high-temperature resistance and sealing performance. The capacitor core is made by soaking the core in a high-temperature resistant electrolyte. The core is formed by winding an anode aluminum foil, a cathode aluminum foil and electrolytic paper, and the electrolytic paper is arranged between the anode aluminum foil and the cathode aluminum foil.

[0047] The high temperature resistant aluminum electrolytic capacitor is manufactured by the following preparation process: S1, stacking the anode aluminum foil, electrolytic paper and cathode aluminum foil in sequence from the inside to the outside and winding them to form a core; S2, immersing the core body in a high temperature resistant electrolyte, the immersion process is pressurized immersion, the pressurized pressure is 0.2 MPa, the immersion number is 3, and each immersion time is 5 minutes, to obtain a capacitor core; S3. Place the capacitor core in the shell and seal it with a rubber plug to obtain a high-temperature resistant electrolytic capacitor.

[0048] Example 2-3 The difference between Example 2-3 and Example 1 is that the source of the high temperature resistant electrolyte is different and the soaking conditions in step S2 are different. See Table 2 below for details.

[0049] Table 2 Parameters of Examples 1-3 Examples 4-9 The difference between Examples 4-9 and Example 1 is that the sources of the high temperature resistant electrolyte are different, see Table 3 below for details.

[0050] Table 3 Sources of high temperature resistant electrolytes of Examples 4-9 Example Source of high temperature resistant electrolyte Example 4 Preparation Example 4 Example 5 Preparation Example 5 Example 6 Preparation Example 6 Example 7 Preparation Example 7 Example 8 Preparation Example 8 Example 9 Preparation Example 9 Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 9 is that the high temperature resistant electrolyte is derived from the preparation of Comparative Example 1, and the rest is the same as Example 9.

[0051] Comparative Example 2 The difference between Comparative Example 2 and Example 9 is that the high temperature resistant electrolyte is derived from the preparation of Comparative Example 2, and the rest is the same as Example 9.

[0052] Performance testing The performance of the high-temperature resistant aluminum electrolytic capacitors prepared in Examples 1-9 and Comparative Examples 1-2 was tested as follows: High-temperature resistant aluminum electrolytic capacitors are standard products with a temperature range of -40°C to +105°C, a diameter of 6.3mm, and a height of 7.7mm.

[0053] After applying a rated voltage of 100V at 105°C with maximum ripple current for 2000h, the capacitance, loss tangent (DF) and leakage current are tested respectively. The capacitance is qualified if it is within 20% of the initial value, the loss tangent does not exceed 200% of the initial value, and the leakage current does not exceed 200% of the initial value. The capacitance change rate, loss tangent change rate and leakage current change rate are used for characterization, that is, the capacitance change rate is ≤20%, the loss tangent change rate is ≤100%, and the leakage current change rate is ≤100%; Capacitance change rate = (capacitance before test - capacitance after test) / capacitance before test * 100%; Loss tangent value change rate = (loss tangent value after test - loss tangent value before test) / loss tangent value before test * 100%; Leakage current change rate = (leakage current after test - leakage current before test) / leakage current before test * 100%.

[0054] Capacitance and loss tangent value testing: Use an impedance analyzer at 25°C and 120Hz frequency; Leakage current test: Use a leakage current tester to test at 25°C.

[0055] The following are the performance test data of the high temperature resistant aluminum electrolytic capacitors of Examples 1-9 and Comparative Examples 1-2, see Table 4 below for details.

[0056] Table 4 Performance data of Examples 1-9 and Comparative Examples 1-2 From Table 4 above, we can conclude that: Compared with Examples 1-3, Examples 4-5 show a lower rate of change in capacitance, a lower rate of change in loss tangent, and a lower rate of change in leakage current of the aluminum electrolytic capacitor, indicating that the use of a stabilizer composed of laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a preferred weight ratio can improve the high-temperature electrolytic stability of the high-temperature resistant electrolyte.

[0057] Compared with Example 4, Examples 6-7 further optimize the type and proportion of glycidyl ester substances, and the change rate of capacitance of the obtained aluminum electrolytic capacitors is reduced, the change rate of loss tangent is reduced, and the change rate of leakage current is also reduced.

[0058] Compared with Example 7, Examples 8-9 further optimize the type and proportion of the flash voltage enhancer. The change rate of the capacitance of the obtained aluminum electrolytic capacitor is reduced, the change rate of the loss tangent value is reduced, and the change rate of the leakage current is also reduced, indicating that the flash voltage enhancer of the present application can have a positive effect on the aluminum electrolytic capacitor of the present application.

[0059] Compared with Example 9, Comparative Example 1 replaces the glycidyl ester substance, and compared with Example 9, Comparative Example 2 replaces the stabilizer. The capacitance change rate of the obtained aluminum electrolytic capacitor is greater than 20%, and the loss tangent value and leakage current are both greater than 100%, indicating that the stabilizer, glycidyl ester substance and flash voltage enhancer of the present application have a good synergistic effect and can synergistically improve the high temperature stability of the aluminum electrolytic capacitor.

[0060] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high temperature resistant aluminum electrolytic capacitor, characterized in that: The invention comprises a shell, a capacitor core and a rubber plug, wherein the capacitor core is accommodated in the shell, the rubber plug is used to seal the shell, the capacitor core is made by soaking the core in a high-temperature resistant electrolyte, the core is formed by winding an anode aluminum foil, a cathode aluminum foil and an electrolytic paper, and the electrolytic paper is arranged between the anode aluminum foil and the cathode aluminum foil; the high-temperature resistant electrolyte is made of the following raw materials in the following weight percentages: 55-64% solvent, 20-30% solute, 4-8% stabilizer, 3-4.5% glycidyl ester substance, 2-4% flash voltage enhancer, 1.5-3.5% corrosion inhibitor and 0.5-1% hydrogen remover.

2. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The solvent consists of ethylene glycol, gamma-caprolactone, ethylene glycol monobutyl ether and diethylene glycol in a weight ratio of (3-4): (1-2): (1.5-2.5):

1.

3. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The solute is a combination of at least two of ammonium hydrogen phosphate, ammonium sebacate, ammonium azelate, and ammonium adipate.

4. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The stabilizer consists of laurylamine dipropylene diamine and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a weight ratio of 1:(0.2-0.4).

5. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The glycidyl ester substance consists of diglycidyl 1,2-cyclohexanedicarboxylate and diglycidyl tetrahydrophthalate in a weight ratio of (2-4):

1.

6. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The flash voltage enhancer is prepared by kneading nano silicon dioxide and 2-octenyl succinic anhydride in a weight ratio of 10:(0.4-0.6).

7. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The corrosion inhibitor is any one or a combination of a phosphate corrosion inhibitor, a benzotriazole corrosion inhibitor, and a quaternary ammonium salt corrosion inhibitor.

8. The high temperature resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The hydrogen remover is any one or a combination of p-nitrobenzoic acid, p-nitroanisole, p-nitrobenzyl alcohol, and p-nitrophenol.

9. A process for preparing a high temperature resistant aluminum electrolytic capacitor according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, stacking the anode aluminum foil, electrolytic paper and cathode aluminum foil in sequence from the inside to the outside and winding them to form a core; S2, immersing the core in a high temperature resistant electrolyte to obtain a capacitor core; S3. Place the capacitor core in the shell and seal it with a rubber plug to obtain a high-temperature resistant electrolytic capacitor.

10. The process for preparing a high temperature resistant aluminum electrolytic capacitor according to claim 9, characterized in that: The immersion in step S2 is pressurized immersion, the pressurized pressure is 0.2-0.4 MPa, the number of immersions is 3-5 times, and the immersion time each time is 3-5 minutes.

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