A solid aluminum electrolytic capacitor and a method for preparing the same

Abstract

The present invention belongs to the technical field of capacitor preparation, and specifically relates to a solid aluminum electrolytic capacitor and a preparation method thereof. The preparation method of the solid aluminum electrolytic capacitor provided by the present invention comprises the following steps: S1 uses electrolytic paper to isolate between the anode foil and the cathode foil and winds them into a core package; S2 welds the core package on the iron bar; S3 immerses the core package welded in step S2 into a chemical forming liquid for chemical forming treatment, and performs drying treatment after chemical forming; S4 immerses the core package dried in step S3 in a pretreatment agent, takes it out and dries it, and then undergoes impregnation treatment and subsequent treatment to obtain the solid aluminum electrolytic capacitor; the chemical forming liquid in step S3 is an aqueous solution containing ammonium adipate, diammonium dihydrogen phosphate, phosphoric acid and malic acid. The method provided by the present invention can effectively improve the consistency of the capacity, ESR, and leakage current of the solid aluminum electrolytic capacitor, improve the consistency of the product's electrical performance, and extend the service life of the solid aluminum electrolytic capacitor product.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitor preparation, and in particular relates to a solid aluminum electrolytic capacitor and a preparation method thereof. Background Art

[0002] As the market demand for high-power, small-volume electrical products (including power supplies) increases, this also translates into electrical (including power supply) manufacturers putting forward requirements for smaller volume and larger ripple current to aluminum electrolytic capacitor manufacturers. Under this call, only solid-state capacitors (including solid-hybrid capacitors) can meet the requirements of large ripple, long life, and small volume. Chinese patent application CN102396040A discloses a solid electrolytic capacitor. On the dielectric layer of the capacitor element, a first conductive polymer layer is formed, which is synthesized by oxidative polymerization using 2-alkyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin as a monomer, and a second conductive polymer layer is formed thereon, which is synthesized by oxidative polymerization using 2,3-dihydro-thieno[3,4-b][1,4]dioxin or a mixture of 2,3-dihydro-thieno[3,4-b][1,4]dioxin and 2-alkyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin as a monomer. The formation of these first conductive polymer layers and the formation of the second conductive polymer layers are repeated alternately a necessary number of times, and a solid dielectric is formed by these first conductive polymers and the second conductive polymers to prepare a solid electrolytic capacitor. Chinese patent application CN116190110A discloses a method for preparing a chip-type solid electrolytic capacitor, comprising: connecting a valve metal body to a valve metal wafer through a connecting colloid; sintering the valve metal wafer carrying the valve metal body; sequentially forming a dielectric layer and a cathode layer on the surface of the sintered valve metal body, so that the valve metal body dielectric layer and the cathode layer constitute a capacitor element; molding and packaging the valve metal wafer carrying the capacitor element, and exposing the cathode end of the capacitor element; connecting a cathode end plate to the cathode end of the capacitor element; and cutting the valve metal wafer to form a chip-type solid electrolytic capacitor having an anode end plate and a cathode end plate.

[0003] However, solid-state capacitors (including solid-hybrid capacitors) currently have the following problems: (1) poor product capacity consistency; (2) poor product ESR consistency; (3) poor leakage current consistency. The circuits of electrical products (power products) involve series and parallel circuits. If the electrical performance is not uniform, it is very easy to cause uneven distribution and abnormalities. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a solid aluminum electrolytic capacitor and a preparation method thereof. The method provided by the present invention can effectively improve the consistency of the capacitance, ESR, and leakage current of the solid aluminum electrolytic capacitor, improve the consistency of the electrical performance of the product, and extend the service life of the solid aluminum electrolytic capacitor product.

[0005] The technical solution of the present invention is:

[0006] A method for preparing a solid aluminum electrolytic capacitor comprises the following steps:

[0007] S1 uses electrolytic paper to isolate the anode foil and cathode foil and winds them into a core package;

[0008] S2 welds the core package to the iron bar;

[0009] S3: immersing the core package welded in step S2 into a chemical forming solution for chemical forming treatment, and then treating the core package to obtain a dried core package;

[0010] S4: soaking the core package dried in step S3 in a pretreatment agent, taking it out and drying it, and then performing an impregnation treatment and subsequent treatment to obtain the solid aluminum electrolytic capacitor;

[0011] The chemical conversion solution in step S3 is an aqueous solution containing ammonium adipate, diammonium dihydrogen phosphate, phosphoric acid and malic acid.

[0012] Furthermore, the concentration of ammonium adipate in the chemical formation liquid is 135-160 g / L, the concentration of ammonium dihydrogen phosphate is 12-15 g / L, the concentration of phosphoric acid is 15-25 mL / L, and the concentration of malic acid is 2-5 g / L.

[0013] The composition and ratio of the formation liquid are key factors affecting the leakage current of aluminum electrolytic capacitor products and the service life of aluminum electrolytic capacitors. The formation liquid prepared by the present invention using a specific composition and ratio can improve the uniformity of the oxide film of the anode foil, reduce the leakage current of solid aluminum electrolytic capacitor products, improve the consistency of product electrical performance, and increase the service life of solid aluminum electrolytic capacitor products.

[0014] Furthermore, the temperature of the formation treatment in step S3 is 65-75° C. and the time is 20-60 minutes.

[0015] Furthermore, after the formation treatment in step S3 is completed, the sample is cleaned, placed in an oven maintained at a temperature of 180°C-250°C after cleaning, and kept for 30-90 minutes for carbonization. After carbonization, it is immersed in the formation liquid again for re-formation treatment, and then cleaned. After the cleaning is completed, it is placed in an oven at a temperature of 110°C-150°C for drying, and the drying time is 10-30 minutes.

[0016] Furthermore, the pre-treatment agent in step S4 includes a silane coupling agent and a solvent, and the content of the silane coupling agent is 0.05-0.1% of the mass of the pre-treatment agent.

[0017] Furthermore, the silane coupling agent is two or more of a vinyl silane coupling agent, an epoxy silane coupling agent, an amino silane coupling agent, and a mercapto siloxane coupling agent.

[0018] Furthermore, the silane coupling agent includes γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

[0019] Furthermore, the silane coupling agent is composed of γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 3-5:1.

[0020] The invention not only facilitates the uniform dispersion of the silane coupling agent on the material surface by adding a special pretreatment agent, but also improves the adhesion between the conductive polymer and the aluminum oxide film layer, and well connects the two, thereby achieving the effects of improving the consistency of capacity, ESR, and leakage current, and extending the service life of solid aluminum electrolytic capacitor products.

[0021] Furthermore, the step S4 is performed for immersion for 5-10 minutes.

[0022] Furthermore, the specific operation of drying in step S4 is: placing the core package soaked with the pre-treatment agent in an oven at 100-115° C. and baking for 20-40 minutes.

[0023] The present invention soaks the dried core package in a pretreatment agent and then dries it, so that the pretreatment agent can be evenly attached to the surface of the aluminum oxide film anode foil, further reducing the leakage current of the solid aluminum electrolytic capacitor product, improving the consistency of the product's electrical performance, and increasing the service life of the solid aluminum electrolytic capacitor product.

[0024] Furthermore, the impregnation treatment and subsequent treatment operations in step S4 are specifically as follows:

[0025] The core package which has been soaked in the pretreatment agent and then dried is first impregnated with a monomer solution, then dried, then impregnated with an oxidant, and then thermally polymerized to form a conductive polymer core package, and then assembled, cleaned, and aged to make a solid capacitor;

[0026] Alternatively, the core package that has been soaked in the pretreatment agent and then dried is first impregnated with the dispersion, then dried, then impregnated with the dispersion, then dried, and then impregnated with the electrolyte to form a core package of a solid hybrid product, which is then assembled → cleaned → aged to produce a solid hybrid capacitor.

[0027] Furthermore, during the drying operation of making the solid capacitor, the core package treated with the monomer solution is placed in an oven at 110-150° C. for 10-30 minutes;

[0028] When making the solid capacitor impregnation in the present invention, the monomer solution is first impregnated, then dried, and then impregnated with an oxidant, which is more conducive to the monomer and the oxidant mixing to form a conductive polymer.

[0029] Furthermore, the monomer solution is a solution prepared from 3,4-ethylenedioxythiophene and anhydrous ethanol.

[0030] Furthermore, the oxidant is a solution prepared from ferric p-toluenesulfonate and anhydrous ethanol.

[0031] Furthermore, a stepwise heating method is used for thermal polymerization, specifically: heating to 30-35°C and keeping for 35-45 minutes; heating to 50-55°C and keeping for 25-35 minutes; heating to 65-70°C and keeping for 45-55 minutes; heating to 85-90°C and keeping for 45-55 minutes; heating to 105-110°C and keeping for 25-35 minutes; heating to 125-130°C and keeping for 35-45 minutes; heating to 175-180°C and keeping for 15-25 minutes.

[0032] The present invention adopts a gradual temperature increase method for thermal polymerization, which can make the conductive polymer chain formed by polymerization as strong as possible at low temperature, which is convenient for reducing the ESR value of the product. The gradual temperature increase is convenient for removing ethanol in the dissolved oxidant; after high temperature, the core after polymerization contains extremely low water content (humidity has a great influence on the conductive polymer); the conductive polymer has high consistency, maintaining the consistency of product capacity, loss and leakage current.

[0033] Furthermore, the dispersion is a conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS).

[0034] The electrolyte used in making the solid hybrid capacitor is a commonly used electrolyte in this field.

[0035] Another object of the present invention is to provide a solid aluminum electrolytic capacitor prepared by the above-mentioned preparation method.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) The method provided by the present invention can effectively improve the consistency of the capacitance, ESR, and leakage current of solid-state aluminum electrolytic capacitors, enhance the consistency of product electrical performance, and extend the service life of solid-state aluminum electrolytic capacitor products.

[0038] (2) The method provided by the present invention can improve the product yield rate. DETAILED DESCRIPTION

[0039] The present invention is further illustrated below through the description of specific implementation modes, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0040] Embodiment 1: A method for preparing a solid aluminum electrolytic capacitor

[0041] The method for preparing the solid aluminum electrolytic capacitor comprises the following steps:

[0042] S1 uses electrolytic paper to separate the anode foil and cathode foil, which have valve metal properties and have an oxide film (aluminum oxide film) formed on the surface by electrochemistry, and winds them into a core package; the electrolytic paper is low-density electrolytic paper MJ235-40 produced by Zhejiang Kaien New Materials Co., Ltd.;

[0043] S2 welds the core package to the iron bar;

[0044] S3: immersing the core package welded in step S2 into a forming liquid for forming treatment at a temperature of 65° C. for 20 minutes, washing after forming, placing in an oven maintained at 180° C. for 90 minutes for carbonization, and immersing in the forming liquid again for re-forming treatment at a temperature of 65° C. for 20 minutes after carbonization, and then washing and placing in an oven at 110° C. for drying for 30 minutes.

[0045] S4: soak the core package dried in step S3 in a pretreatment agent for 5 minutes, and then take it out for drying. The specific operation of drying is: place the core package soaked in the pretreatment agent in an oven at 105°C for 30 minutes;

[0046] S5: the core package treated with the pretreatment agent in step S4 is first impregnated with the monomer solution, and then dried. The specific operation of drying is: the core package treated with the monomer solution is placed in a 110° C. oven for 30 minutes, then impregnated with an oxidant, and then thermally polymerized to form a conductive polymer core package, and then assembled → cleaned → aged to make a solid capacitor;

[0047] The chemical formation liquid in step S3 is an aqueous solution containing ammonium adipate, diammonium hydrogen phosphate, phosphoric acid and malic acid; the concentration of ammonium adipate in the chemical formation liquid is 135 / L, the concentration of diammonium hydrogen phosphate is 12g / L, the concentration of phosphoric acid is 15mL / L, and the concentration of malic acid is 2g / L.

[0048] The pretreatment agent in step S4 includes a silane coupling agent and a solvent, wherein the content of the silane coupling agent is 0.05% of the mass of the pretreatment agent; the silane coupling agent is composed of γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 3:1; and the solvent is ethanol;

[0049] The monomer solution in step S5 is a solution prepared from 3,4-ethylenedioxythiophene and anhydrous ethanol, and the mass percentage of 3,4-ethylenedioxythiophene in the monomer solution is 10%; the oxidant is a solution prepared from ferric p-toluenesulfonate and anhydrous ethanol, and the mass percentage of ferric p-toluenesulfonate in the oxidant is 40%;

[0050] The step S5 adopts a gradual heating method for thermal polymerization, specifically: heating to 30°C and keeping for 45 minutes; heating to 50°C and keeping for 35 minutes; heating to 65°C and keeping for 55 minutes; heating to 85°C and keeping for 55 minutes; heating to 105°C and keeping for 35 minutes; heating to 125°C and keeping for 45 minutes; heating to 175°C and keeping for 25 minutes.

[0051] Embodiment 2: A method for preparing a solid aluminum electrolytic capacitor

[0052] The method for preparing the solid aluminum electrolytic capacitor comprises the following steps:

[0053] S1 uses electrolytic paper to separate the anode foil and cathode foil with valve metal properties and an oxide film formed on the surface by electrochemistry and wound into a core package; the electrolytic paper is low-density electrolytic paper MJ235-40 produced by Zhejiang Kaien New Materials Co., Ltd.;

[0054] S2 welds the core package to the iron bar;

[0055] S3: immersing the core package welded in step S2 into a forming liquid for forming treatment at a temperature of 75° C. for 60 minutes, washing after forming, placing in an oven maintained at 250° C. for 30 minutes for carbonization, and immersing in the forming liquid again for re-forming treatment at a temperature of 75° C. for 60 minutes after carbonization, and then washing and placing in an oven at 150° C. for drying for 10 minutes after washing;

[0056] S4: soak the core package dried in step S3 in a pretreatment agent for 10 minutes, and then take it out for drying. The specific operation of drying is: place the core package soaked in the pretreatment agent in an oven at 105°C for 30 minutes;

[0057] S5: the core package treated with the pretreatment agent in step S4 is first impregnated with the monomer solution, and then dried. The specific operation of drying is: the core package treated with the monomer solution is placed in a 150° C. oven, dried for 10 minutes, then impregnated with an oxidant, and then thermally polymerized to form a conductive polymer core package, and then assembled → cleaned → aged to make a solid capacitor;

[0058] The chemical formation liquid in step S3 is an aqueous solution containing ammonium adipate, diammonium hydrogen phosphate, phosphoric acid and malic acid; the concentration of ammonium adipate in the chemical formation liquid is 160g / L, the concentration of diammonium hydrogen phosphate is 15g / L, the concentration of phosphoric acid is 25mL / L, and the concentration of malic acid is 5g / L.

[0059] The pretreatment agent in step S4 includes a silane coupling agent and a solvent, wherein the content of the silane coupling agent is 0.1% of the mass of the pretreatment agent; the silane coupling agent is composed of γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 5:1; and the solvent is petroleum ether;

[0060] The monomer solution in step S5 is a solution prepared from 3,4-ethylenedioxythiophene and anhydrous ethanol, and the mass percentage of 3,4-ethylenedioxythiophene in the monomer solution is 40%; the oxidant is a solution prepared from ferric p-toluenesulfonate and anhydrous ethanol, and the mass percentage of ferric p-toluenesulfonate in the oxidant is 65%;

[0061] The step S5 adopts a gradual heating method for thermal polymerization, specifically: heating to 35°C and keeping for 35 minutes; heating to 55°C and keeping for 25 minutes; heating to 70°C and keeping for 45 minutes; heating to 90°C and keeping for 45 minutes; heating to 110°C and keeping for 25 minutes; heating to 130°C and keeping for 35 minutes; heating to 180°C and keeping for 15 minutes.

[0062] Embodiment 3: A method for preparing a solid aluminum electrolytic capacitor

[0063] The method for preparing the solid aluminum electrolytic capacitor comprises the following steps:

[0064] S1 uses electrolytic paper to separate the anode foil and cathode foil with valve metal properties and an oxide film formed on the surface by electrochemistry and wound into a core package; the electrolytic paper is low-density electrolytic paper MJ235-40 produced by Zhejiang Kaien New Materials Co., Ltd.;

[0065] S2 welds the core package to the iron bar;

[0066] S3: immersing the core package welded in step S2 into a forming liquid for forming treatment at a temperature of 70° C. for 40 minutes, washing after forming, placing in an oven maintained at a temperature of 210° C. for 50 minutes for carbonization, and immersing in the forming liquid again for re-forming treatment at a temperature of 70° C. for 40 minutes after carbonization, and then washing and placing in an oven at a temperature of 120° C. for drying for 20 minutes after washing;

[0067] S4: soak the core package dried in step S3 in a pretreatment agent for 8 minutes, and then take it out for drying. The specific operation of drying is: place the core package soaked in the pretreatment agent in an oven at 105°C for 30 minutes;

[0068] S5: the core package treated with the pretreatment agent in step S4 is first impregnated with the monomer solution, and then dried. The specific operation of drying is: placing the core package treated with the monomer solution in a 120° C. oven for 20 minutes; then impregnating with an oxidant, and then thermally polymerizing to form a conductive polymer core package, and then assembling → cleaning → aging to make a solid capacitor;

[0069] The chemical formation liquid in step S3 is an aqueous solution containing ammonium adipate, diammonium hydrogen phosphate, phosphoric acid and malic acid; the concentration of ammonium adipate in the chemical formation liquid is 150 g / L, the concentration of diammonium hydrogen phosphate is 13.5 g / L, the concentration of phosphoric acid is 20 mL / L, and the concentration of malic acid is 3 g / L.

[0070] The pretreatment agent in step S4 includes a silane coupling agent and a solvent, wherein the content of the silane coupling agent is 0.07% of the mass of the pretreatment agent; the silane coupling agent is composed of γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 4:1; and the solvent is ethyl acetate;

[0071] The monomer solution in step S5 is a solution prepared from 3,4-ethylenedioxythiophene and anhydrous ethanol, and the mass percentage of 3,4-ethylenedioxythiophene in the monomer solution is 25%; the oxidant is a solution prepared from ferric p-toluenesulfonate and anhydrous ethanol, and the mass percentage of ferric p-toluenesulfonate in the oxidant is 50%;

[0072] The step S5 adopts a gradual heating method for thermal polymerization, specifically: heating to 30°C and keeping for 40 minutes; heating to 50°C and keeping for 30 minutes; heating to 65°C and keeping for 50 minutes; heating to 85°C and keeping for 50 minutes; heating to 105°C and keeping for 30 minutes; heating to 125°C and keeping for 40 minutes; heating to 175°C and keeping for 20 minutes.

[0073] Comparative Example 1: A method for preparing a solid aluminum electrolytic capacitor

[0074] The method for improving the polymerization consistency of the solid aluminum electrolytic capacitor is similar to that of Example 3, and the difference from Example 3 is that step S4 does not include a drying step.

[0075] Comparative Example 2: A method for preparing a solid aluminum electrolytic capacitor

[0076] The method for improving the polymerization consistency of the solid aluminum electrolytic capacitor is similar to that of Example 3, and the difference from Example 3 is that the thermal polymerization in step S5 is specifically as follows: heating to 30° C. and maintaining for 240 minutes; heating to 175° C. and maintaining for 20 minutes.

[0077] Comparative Example 3: A method for preparing a solid aluminum electrolytic capacitor

[0078] The method for improving the polymerization consistency of a solid aluminum electrolytic capacitor is similar to Example 3, except that the chemical formation liquid in step S3 is an aqueous solution containing ammonium adipate, diammonium hydrogen phosphate, phosphoric acid and malic acid; the concentration of ammonium adipate in the chemical formation liquid is 162 g / L, the concentration of diammonium hydrogen phosphate is 3.5 g / L, the concentration of phosphoric acid is 20 mL / L, and the concentration of malic acid is 1 g / L.

[0079] Comparative Example 4: A method for preparing a solid aluminum electrolytic capacitor

[0080] The method for improving the polymerization consistency of a solid aluminum electrolytic capacitor is similar to that of Example 3, except that the silane coupling agent is composed of γ-aminopropyltrimethoxysilane and γ-(2,3-epoxypropyloxy)propyltrimethoxysilane in a mass ratio of 3:1.

[0081] Test Example 1: Conventional electrical performance test

[0082] 1. Test materials: According to the methods of Example 3, Comparative Example 1 and Comparative Example 3, capacitors with specifications of 25V 470μF and dimensions of 10×12.5 were prepared, with 10 capacitors in each group, for a total of 30 capacitors.

[0083] 2. Test methods:

[0084] LCR bridge test is adopted. The test frequency of capacity (CAP) and loss (DF) is 120HZ, and the test frequency of equivalent series resistance (ESR) is 100KHZ; leakage current (LC) test adopts leakage current tester (test voltage is the rated working voltage of capacitor).

[0085] 3. Test results:

[0086] The test results are shown in Table 1.

[0087] Table 1: Conventional electrical performance test results

[0088]

[0089]

[0090]

[0091] It can be seen from Table 1 that the capacitor prepared by the method of Example 3 of the present invention has a large capacity, small loss, small leakage current, and low equivalent series resistance. Compared with the capacitors prepared by the methods of Comparative Examples 1 and 3, the capacitor prepared by the method of the present invention has a larger capacity, smaller loss, smaller leakage current, and lower equivalent series resistance, and the consistency of the capacitor's capacity, equivalent series resistance, and leakage current is better, which shows that the present invention can improve the consistency of the product's electrical performance.

[0092] Test Example 3: High Temperature Durability Test

[0093] 1. Test materials: According to the methods of Example 3, Comparative Example 2 and Comparative Example 4, capacitors with specifications of 25V 470μF and dimensions of 10×10.2 were prepared, with 10 capacitors in each group, for a total of 30 capacitors.

[0094] 2. Test method:

[0095] LCR bridge test is adopted. The test frequency of capacity (CAP) and loss (DF) is 120HZ, and the test frequency of equivalent series resistance (ESR) is 100KHZ; leakage current (LC) test adopts leakage current tester (test voltage is the rated working voltage of capacitor).

[0096] 3. Test methods:

[0097] (1) Before the test begins, test the product's capacity (CAP), loss (DF), equivalent series resistance (ESR), and leakage current (LC). (2) Install the product on the test fixture of the ripple power supply, apply voltage to the capacitor (DC voltage + ripple voltage = rated working voltage), and the ripple current is the nominal ripple current value; then put the product in a 125°C oven. After a specific time, take it out and test its related electrical performance parameters, and then repeat the action (2).

[0098] 3. Test results:

[0099] The test results are shown in Table 2-6.

[0100] Table 2 Initial values ​​of capacitor electrical properties

[0101]

[0102]

[0103] Table 3 Electrical performance test values ​​of capacitors after 1000h

[0104]

[0105]

[0106] Table 4 Electrical performance test values ​​of capacitors after 2000h

[0107]

[0108]

[0109] Table 5 Electrical performance test values ​​of capacitors after 3000h

[0110]

[0111]

[0112] Table 6 Electrical performance test values ​​of capacitors after 4000h

[0113]

[0114]

[0115]

[0116] It can be seen from Table 2-6 that, compared with the capacitors prepared by the methods of Comparative Examples 2 and 4, the capacitors prepared by the method of the present invention have larger capacity, smaller loss, smaller leakage current, and lower equivalent series resistance after 4000 hours, and the consistency of the capacity, equivalent series resistance, and leakage current of the capacitor is better, which shows that the present invention can improve the consistency of the electrical performance of the product and extend the service life of the solid aluminum electrolytic capacitor product.

Claims

1. A method for preparing a solid aluminum electrolytic capacitor, characterized in that: The following steps are involved: S1 uses electrolytic paper to separate the anode foil and cathode foil, which have valve metal properties and have aluminum oxide film formed on the surface by electrochemistry, and then they are wound into a core package; S2 welds the core package to the iron bar; S3: immersing the core package welded in step S2 into a forming solution for forming treatment, and drying the core package after forming; S4: soaking the core package dried in step S3 in a pretreatment agent, taking it out and drying it, and then performing an impregnation treatment and subsequent treatment to obtain the solid aluminum electrolytic capacitor; The chemical formation liquid in step S3 is an aqueous solution containing ammonium adipate, diammonium phosphate, phosphoric acid and malic acid; the concentration of ammonium adipate in the chemical formation liquid is 135-160 g / L, the concentration of diammonium phosphate is 12-15 g / L, the concentration of phosphoric acid is 15-25 mL / L, and the concentration of malic acid is 2-5 g / L; The pretreatment agent in step S4 includes a silane coupling agent and a solvent, and the content of the silane coupling agent is 0.05-0.1% of the mass of the pretreatment agent; the silane coupling agent includes γ-aminopropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

2. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: The specific operation of drying in step S4 is: placing the core package soaked with the pre-treatment agent in an oven at 100-115° C. and drying for 20-40 minutes.

3. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: After the formation treatment in step S3 is completed, the reaction mixture is cleaned, placed in an oven maintained at a temperature of 180°C-250°C, and carbonized for 30-90 minutes. After carbonization, the reaction mixture is immersed in the formation liquid again for re-formation treatment, and then cleaned. After the cleaning is completed, the reaction mixture is placed in an oven maintained at a temperature of 110°C-150°C for drying, and the drying time is 10-30 minutes.

4. The method for preparing a solid aluminum electrolytic capacitor according to claim 1, characterized in that: The impregnation treatment and subsequent treatment operations in step S4 are specifically as follows: The core package which has been soaked in the pretreatment agent and then dried is first impregnated with a monomer solution, then dried, then impregnated with an oxidant, and then thermally polymerized to form a conductive polymer core package, and then assembled, cleaned, and aged to make a solid capacitor; Alternatively, the core package that has been soaked in the pretreatment agent and then dried is first impregnated with the dispersion, then dried, then impregnated with the dispersion, then dried, and then impregnated with the electrolyte to form a core package of a solid hybrid product, which is then assembled → cleaned → aged to produce a solid hybrid capacitor.

5. The method for preparing a solid aluminum electrolytic capacitor according to claim 4, characterized in that: The monomer solution is a solution prepared from 3,4-ethylenedioxythiophene and anhydrous ethanol; the oxidant is a solution prepared from ferric p-toluenesulfonate and anhydrous ethanol.

6. The method for preparing a solid aluminum electrolytic capacitor according to claim 4, characterized in that: The thermal polymerization is carried out by a gradual heating method, specifically: heating to 30-35°C, keeping for 35-45 minutes; heating to 50-55°C, keeping for 25-35 minutes; heating to 65-70°C, keeping for 45-55 minutes; heating to 85-90°C, keeping for 45-55 minutes; heating to 105-110°C, keeping for 25-35 minutes; heating to 125-130°C, keeping for 35-45 minutes; heating to 175-180°C, keeping for 15-25 minutes.

7. A solid aluminum electrolytic capacitor prepared by the preparation method according to any one of claims 1 to 6.

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