Impregnation preparation method for hybrid aluminum electrolytic capacitor

Abstract

The present invention relates to the technical field of capacitors, and disclosed is an impregnation preparation method for a hybrid aluminum electrolytic capacitor. The method comprises at least the following steps: soaking a corroded anode aluminum foil and a corroded cathode aluminum foil in citrate; placing electrolytic paper between the anode aluminum foil and the cathode aluminum foil and winding same into a core package; impregnating at least one half of the volume of the core package from one end in an impregnation solution for first impregnation treatment, then inverting the core package, and impregnating at least the remaining half of the volume of the core package from the other end in the impregnation solution for second impregnation treatment; drying the core package having undergone the second impregnation treatment; and assembling the dried core package with an aluminum case and a sealing plug and aging same to obtain a hybrid aluminum electrolytic capacitor. The impregnation preparation method for a hybrid aluminum electrolytic capacitor provided by the present application greatly shortens the impregnation time, improves the impregnation efficiency and consistency, and improves the performance of the capacitor.

Description

An impregnation preparation method for a hybrid aluminum electrolytic capacitor Technical Field

[0001] This invention relates to the field of capacitor technology, and more specifically to an impregnation preparation method for a hybrid aluminum electrolytic capacitor. Background Technology

[0002] Capacitors are fundamental components in circuit design and have a wide range of applications. Depending on the dielectric material used, capacitors can be classified into various types, such as aluminum electrolytic capacitors, ceramic capacitors, film capacitors, tantalum capacitors, and supercapacitors. Among these, aluminum electrolytic capacitors hold a large market share due to their high cost-effectiveness and high capacitance. Aluminum electrolytic capacitors can be further divided into three categories: liquid capacitors, solid capacitors, and hybrid solid-liquid capacitors. In recent years, hybrid solid-liquid capacitors, combining the advantages of both solid and liquid capacitors, have gradually become the preferred choice for aluminum electrolytic capacitors due to their high capacitance yield, low ESR, high temperature resistance, long lifespan, moisture resistance, and vibration resistance. Technical issues

[0003] In the traditional impregnation process of aluminum electrolytic capacitor cores, the cores of the capacitors to be impregnated are first dried. Then, different impregnation devices and electrolytes are selected according to the different materials and specifications of the capacitors. They are then placed into different impregnation sieves, and then the impregnation sieves are completely immersed in vacuum tanks containing different electrolytes. During the impregnation process, positive and negative pressures are applied in cycles to achieve complete impregnation. After impregnation for a period of time, the excess electrolyte on the capacitor cores is removed and the impregnation effect is removed. Finally, the impregnation effect is manually checked by the staff. This impregnation method is complicated to operate, takes a long time, and the impregnation effect is difficult to control. It requires a lot of machines, which greatly increases the production cost and labor cost. Therefore, the existing impregnation preparation method of hybrid aluminum electrolytic capacitors has defects such as long impregnation time, insufficient impregnation, and poor consistency of impregnation effect, which greatly limits the use of this technology. Technical solutions

[0004] The purpose of this invention is to provide an impregnation preparation method for a hybrid aluminum electrolytic capacitor, solving the following technical problems:

[0005] Existing impregnation preparation methods for hybrid aluminum electrolytic capacitors suffer from problems such as long impregnation time, insufficient impregnation, and poor consistency of impregnation effect.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An impregnation preparation method for a hybrid aluminum electrolytic capacitor includes at least the following steps:

[0008] The corroded anode and cathode aluminum foils were treated by soaking in citrate.

[0009] Electrolytic paper is placed between the anode aluminum foil and the cathode aluminum foil and wound into a core package;

[0010] At least half of the volume of the core package is immersed in the impregnation liquid from one end for a first impregnation treatment, and then the core package is inverted and the remaining at least half of the volume of the core package is immersed in the impregnation liquid from the other end for a second impregnation treatment.

[0011] The core package after the second impregnation treatment is then dried.

[0012] The dried core is assembled with an aluminum shell and a stopper and then aged to obtain a hybrid aluminum electrolytic capacitor.

[0013] As a further aspect of the present invention: the concentration of the citrate is 1-3 g / L, the temperature is 90-100℃, and the soaking time is 5-10 min.

[0014] As a further aspect of the present invention, the impregnating liquid is at least one of the following: a chemical solution, a dispersion, and an electrolyte.

[0015] As a further aspect of the present invention: the dispersion is an aqueous compound containing poly(3,4-vinyldioxothiophenol) / polybenzenesulfonate, the formation solution is an ammonium adipate-based formation solution or a boric acid-based formation solution, and the electrolyte includes at least one of ethylene glycol, γ-butyrolactone, N,N-dimethylformamide, sulfolane, water, and polyethylene glycol.

[0016] As a further aspect of the present invention: the first impregnation treatment and the second impregnation treatment adopt vacuum pressure impregnation, and the vacuum degree is -0.08-0.15MPa.

[0017] As a further aspect of the present invention: the first impregnation treatment time is 5-30 min and the temperature is 40-90℃, and the second impregnation treatment time is 5-30 min and the temperature is 40-90℃.

[0018] As a further aspect of the present invention: the drying temperature is 125-200℃ and the time is 60-120min. Beneficial effects

[0019] The beneficial effects of this invention are:

[0020] (1) This invention simplifies the impregnation process, shortens the impregnation time, and reduces problems such as insufficient impregnation and poor impregnation consistency by treating the aluminum foil with citrate and impregnating the core package in stages with the impregnation solution. The hybrid aluminum electrolytic capacitor prepared by this application can be widely used in home appliances, computers, servers, communication equipment, mobile phones, fast chargers, optoelectronic products, new energy, high-speed railways, aerospace, automotive industry, military industry and other fields. Specifically, the impregnation method provided by this invention uses a staged impregnation mode to sequentially impregnate the aluminum foil with the dispersion solution, the formation solution and the electrolyte to obtain the hybrid aluminum electrolytic capacitor. The impregnation process is divided into a first impregnation treatment and a second impregnation treatment. The first impregnation treatment and the second impregnation treatment are vacuum impregnated from both ends of the core package, which makes it easier for the impregnation solution to penetrate into the core package, greatly shortens the impregnation time, improves the impregnation efficiency and consistency, and improves the performance of the capacitor. Compared to the single-stage impregnation method, this method ensures that the impregnating liquid is fully and evenly immersed in the core after the first and second impregnation treatments, avoiding insufficient or uneven impregnation or impregnating liquid residue. At the same time, the multi-stage impregnation method is easier, reduces impregnation time, avoids the impact of heating time on the impregnation efficiency, and improves the stability and consistency of the final hybrid aluminum electrolytic capacitor product. It can also significantly reduce the leakage current of the hybrid aluminum electrolytic capacitor product.

[0021] Using the impregnation method of this invention, the impregnation time for small core packages (e.g., 8-12mm in diameter) can be shortened to 4-10 minutes. Combined with pressurization, the impregnation time can be further shortened. For large core packages (e.g., 16-18mm in diameter), the first impregnation step can be performed in stages: first impregnating one-third of the core package's volume, then two-thirds. In the second impregnation step, the core package is inverted, and one-third of its volume is impregnated before the remaining two-thirds. This shortens the impregnation time to 20-30 minutes. Combined with pressurization, the impregnation time can be further shortened, significantly improving impregnation efficiency while ensuring the impregnation effect. By setting up the first and second impregnation processes, the core package is completely impregnated in a shorter time. The shorter impregnation time reduces the overall impregnation operation time, significantly reducing the operation cycle and operating costs, and significantly improving production efficiency.

[0022] (2) In this application, the aluminum foil after hydration treatment and before formation is treated with citrate. Because the hydrated oxide film is relatively thick, it is easy to block the micropores in the corrosion foil, resulting in capacitance loss. After anodizing, the surface of the hydrated oxide film is loose and porous, leaving residues, which constitute surface defects of the oxide film, causing capacitance loss and increased leakage current. Treating the hydrated aluminum foil with citrate before formation helps to dissolve the loose and porous outer layer of the hydrated oxide film and eliminate defects. After citrate soaking treatment, the voltage rise rate during formation is significantly increased, the formation time is shortened, the formation efficiency is improved, and electrical energy is saved. Moreover, citrate ions help to increase the crystal content of the anodic oxide film, increase the specific capacitance, and improve the performance of the capacitor. Embodiments of the present invention

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0024] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0025] The hydrated etched aluminum foil was immersed in a 2 g / L deionized trisodium citrate solution at 95°C for 5 min. After being removed, it was rinsed lightly with deionized water. The etched aluminum foil was then cut to obtain anode and cathode aluminum foil. The anode, cathode, and electrolytic paper were then wound into a core package using a core package winding machine. The electrolytic paper was placed between the anode and cathode aluminum foils, and its length was longer than the overlapping part of the anode and cathode aluminum foils.

[0026] The positive and negative leads of the core package are electrically connected to the positive and negative terminals of the power supply, respectively. A voltage is applied to the positive and negative terminals of the core package, and half of the core package is immersed in the forming solution from one end for forming repair treatment for 10 minutes to complete the first immersion treatment. Then, the core package is inverted and the other half of the core package is immersed in the forming solution for forming repair treatment for another 10 minutes to complete the second immersion treatment. The voltage applied to the positive and negative terminals of the core package is 0.8 times the withstand voltage of the anode aluminum foil. The forming solution can be an ammonium adipate-based forming solution from the prior art. The immersion temperature is 50°C and the vacuum degree is -0.09MPa.

[0027] The core package after impregnation into liquid was subjected to heating and drying treatment at a temperature of 150°C for 30 minutes. Then, it was impregnated with a dispersion solution according to the above method, wherein the dispersion solution was a PEDOT / PSS aqueous dispersion solution, the impregnation temperature was 50°C, the vacuum degree was -0.09MPa, the first impregnation treatment time was 8 minutes, and the second impregnation treatment time was 8 minutes.

[0028] The core package after impregnation with the above-mentioned dispersion was subjected to heat drying treatment at a temperature of 150°C for 30 minutes. Then, it was impregnated with electrolyte containing triethylamine, phthalic acid and adipic acid at a temperature of 50°C and a vacuum of -0.09 MPa. The first impregnation treatment lasted for 8 minutes, the second impregnation treatment lasted for 8 minutes, and then the core package was dried at 150°C for 40 minutes to obtain the impregnated core package.

[0029] The impregnated core is assembled with an aluminum shell and a stopper to obtain a semi-finished capacitor. The semi-finished capacitor is then charged and aged by applying voltages of 0.5, 1, and 1.2 times the rated voltage for segmented aging treatment at an aging temperature of 125°C and an aging time of 120 minutes to obtain a hybrid aluminum electrolytic capacitor. Example 2

[0030] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0031] The hydrated etched aluminum foil was immersed in a 2 g / L deionized trisodium citrate solution at 95°C for 10 min. After being removed, it was rinsed lightly with deionized water. The etched aluminum foil was then cut to obtain anode aluminum foil and cathode aluminum foil. The anode aluminum foil, cathode aluminum foil and electrolytic paper were then wound into a core package using a core package winding machine. The electrolytic paper was placed between the anode aluminum foil and the cathode aluminum foil, and the length of the electrolytic paper was longer than the overlapping part of the anode and cathode aluminum foil.

[0032] The remaining components and preparation methods are completely consistent with those in Example 1. Example 3

[0033] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0034] In the impregnation-to-liquid step, the first impregnation treatment time is 12 minutes, and the second impregnation treatment time is 12 minutes.

[0035] In the impregnation dispersion step, the first impregnation treatment time is 10 min, and the second impregnation treatment time is 10 min;

[0036] In the step of impregnating with electrolyte, the first impregnation treatment time is 10 min, and the second impregnation treatment time is 10 min;

[0037] The remaining components and preparation methods are completely consistent with those in Example 1. Example 4

[0038] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0039] In the impregnation-to-liquid step, the first impregnation treatment time is 15 minutes, and the second impregnation treatment time is 15 minutes.

[0040] In the impregnation dispersion step, the first impregnation treatment time is 15 min, and the second impregnation treatment time is 15 min;

[0041] In the step of impregnating with electrolyte, the first impregnation treatment time is 15 min, and the second impregnation treatment time is 15 min;

[0042] The remaining components and preparation methods are completely consistent with those in Example 1.

[0043] Comparative Example 1

[0044] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0045] The hydrated and corroded aluminum foil is directly cut to obtain anode aluminum foil and cathode aluminum foil. Then, the anode aluminum foil, cathode aluminum foil and electrolytic paper are wound into a core package by a core package winding machine. The electrolytic paper is located between the anode aluminum foil and the cathode aluminum foil, and the length of the electrolytic paper is longer than the length of the overlapping part of the anode and cathode aluminum foil to obtain the core package.

[0046] The remaining components and preparation methods are completely consistent with those in Example 1.

[0047] Comparative Example 2

[0048] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0049] In the immersion solution step, the core package is completely immersed in the solution for 16 minutes.

[0050] In the impregnation and dispersion step, the core pack is completely immersed in the dispersion for 20 minutes.

[0051] In the electrolyte impregnation step, the core package is completely immersed in the electrolyte for 20 minutes.

[0052] The remaining components and preparation methods are completely consistent with those in Example 1.

[0053] Comparative Example 3

[0054] The preparation method of hybrid aluminum electrolytic capacitors includes the following steps:

[0055] The hydrated and corroded aluminum foil is directly cut to obtain anode aluminum foil and cathode aluminum foil. Then, the anode aluminum foil, cathode aluminum foil and electrolytic paper are wound into a core package by a core package winding machine. The electrolytic paper is located between the anode aluminum foil and the cathode aluminum foil, and the length of the electrolytic paper is longer than the length of the overlapping part of the anode and cathode aluminum foil to obtain the core package.

[0056] In the immersion solution step, the core package is completely immersed in the solution for 16 minutes.

[0057] In the impregnation and dispersion step, the core pack is completely immersed in the dispersion for 20 minutes.

[0058] In the electrolyte impregnation step, the core package is completely immersed in the electrolyte for 20 minutes.

[0059] The remaining components and preparation methods are completely consistent with those in Example 1.

[0060] Performance testing

[0061] Ten hybrid aluminum electrolytic capacitors of Examples 1-4 and Comparative Examples 1-3 were fabricated. The capacitance (CAP), dissipation factor (DF), and equivalent series resistance (ESR) of these seven products were tested at a frequency of 120Hz. The leakage current (LC) was tested at a voltage of 35V. The test results are shown in Table 1.

[0062] Table 1. Performance test results of the products in Examples 1-4 and Comparative Examples 1-3.

[0063]

[0064] As shown in Table 1, the parameters of the capacitors prepared using the method of the present invention in the above four embodiments all meet the operating standards, and the impregnation liquid is evenly and fully distributed between the aluminum foil and the electrolytic paper. Therefore, the impregnation process of the hybrid aluminum electrolytic capacitor core group provided by the present invention is simple and convenient to operate, and the entire impregnation process can be completed in only 3.5 to 5 hours, which greatly shortens the impregnation time, improves production efficiency, and the quality of the core group after impregnation treatment is good, meeting the operating standards. Compared with the capacitors prepared using the methods of Comparative Examples 1, 2, and 3, the impregnation effect of the core pack of the present invention is better in the same or shorter impregnation time. Moreover, the hybrid aluminum electrolytic capacitor products prepared using the impregnation method provided by the embodiments of the present invention have higher stability in parameters such as capacitance (CAP), loss (DF), leakage current (LC), and equivalent series resistance (ESR), better product consistency, and lower leakage current (LC).

[0065] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for impregnating a hybrid aluminum electrolytic capacitor, characterized in that, At least the following steps are included: The corroded anode and cathode aluminum foils were treated by soaking in citrate. Electrolytic paper is placed between the anode aluminum foil and the cathode aluminum foil and wound into a core package; At least half of the volume of the core package is immersed in the impregnation liquid from one end for a first impregnation treatment, and then the core package is inverted and the remaining at least half of the volume of the core package is immersed in the impregnation liquid from the other end for a second impregnation treatment. The core package after the second impregnation treatment is then dried. The dried core is assembled with an aluminum shell and a stopper and then aged to obtain a hybrid aluminum electrolytic capacitor.

2. The impregnation preparation method for a hybrid aluminum electrolytic capacitor according to claim 1, characterized in that, The concentration of citrate is 1-3 g / L, the temperature is 90-100℃, and the soaking time is 5-10 min.

3. The impregnation preparation method for a hybrid aluminum electrolytic capacitor according to claim 1, characterized in that, The impregnating liquid is at least one of the following: a chemical solution, a dispersion, and an electrolyte.

4. The impregnation preparation method for a hybrid aluminum electrolytic capacitor according to claim 3, characterized in that, The dispersion is an aqueous compound containing poly(3,4-vinyldioxothiophenol) / polybenzenesulfonate, the formation solution is an ammonium adipate-based formation solution or a boric acid-based formation solution, and the electrolyte includes at least one of ethylene glycol, γ-butyrolactone, N,N-dimethylformamide, sulfolane, water, and polyethylene glycol.

5. The impregnation preparation method for a hybrid aluminum electrolytic capacitor according to claim 1, characterized in that, The first impregnation treatment and the second impregnation treatment are performed under vacuum pressure, and the vacuum degree is -0.08-0.15MPa.

6. The impregnation preparation method for a hybrid aluminum electrolytic capacitor according to claim 5, characterized in that, The first impregnation treatment lasts for 5-30 minutes at a temperature of 40-90°C, and the second impregnation treatment lasts for 5-30 minutes at a temperature of 40-90°C.

7. The impregnation preparation method for a hybrid aluminum electrolytic capacitor according to claim 1, characterized in that, The drying temperature is 125-200℃ and the time is 60-120 minutes.

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