Aluminum foil formation additive, high-voltage formed foil complexing depolarization method and aluminum electrolytic capacitor

Abstract

The invention is suitable for the technical field of aluminum foil formation, and provides an aluminum foil formation additive, a high-voltage formed foil complexing depolarization method and an aluminum electrolytic capacitor. The aluminum foil formation additive is composed of diethylenetriaminepenta (methylene phosphonic acid), triethanolamine oleic soap and mannose; the molar ratio of the diethylenetriaminepenta (methylene phosphonic acid) to the triethanolamine oleic soap to the mannose is 1: (3-5): (6-8). The diethylenetriaminepenta (methylene phosphonic acid), the triethanolamine oleic soap and the mannose are compounded according to a specific proportion to generate a synergistic effect, so that blockage caused by an over-thick hydrated oxide film can be effectively dredged, the porous hydrated film is more efficiently removed, and damage to a compact layer is reduced; and finally, the specific volume of the corroded aluminum foil and the overall performance of the electronic aluminum foil formed foil are remarkably improved, and a high-performance aluminum electrolytic capacitor capable of adapting to a harsh working environment can be prepared.

Description

Technical Field

[0001] This application belongs to the field of aluminum foil formation technology, and particularly relates to an aluminum foil formation additive and a method for high-voltage formation foil complexation depolarization, and an aluminum electrolytic capacitor. Background Technology

[0002] In the wave of rapid development in the electronics industry, strategic emerging fields such as new energy vehicles and 5G communications have placed more stringent demands on aluminum electrolytic capacitors. Miniaturization, high voltage withstand capability, and high specific capacitance have become core requirements for industry development. As the core material of aluminum electrolytic capacitors, the performance of high-voltage forming foil directly determines the overall quality of the capacitor, and the evolution of its manufacturing technology is deeply intertwined with the development needs of the electronics industry.

[0003] Traditional electroforming foil technology is gradually showing its limitations in meeting new demands, which has spurred technological innovation in composite structure electroforming foil. In the production process of high-voltage electroforming foil, pretreatment, primary electroforming, intermediate electroforming, secondary electroforming, and post-treatment are all interconnected. Among them, intermediate electroforming, as a key link between primary and secondary electroforming, directly affects the voltage resistance, specific volume, and stability of the electroforming foil, and plays a crucial role in the entire production process.

[0004] Currently, most mature formation processes in the industry use phosphoric acid solution as the intermediate treatment medium. The process flow encompasses multiple steps, including boiling treatment, formation 1, depolarization treatment, formation 2, depolarization treatment, formation 3, depolarization treatment, heat treatment, re-formation, phosphoric acid treatment, and re-formation. Notably, a depolarization treatment step is added after each formation step before heat treatment. Phosphoric acid intermediate treatment dissolves and modifies the oxide film surface, forming a porous structure conducive to uniform oxide film growth during secondary formation. It also effectively removes impurities from the surface of the primary formed film and forms an aluminum phosphate transition layer on the alumina film, thereby improving the film's adhesion. Therefore, it has become a widely used and standard process in the industry.

[0005] However, with the increasing demands on the performance of high-pressure composite foils, the limitations of the phosphoric acid immersion process in actual production have become increasingly apparent. Phosphoric acid treatment can have potential adverse effects on subsequent formation processes, and the process is difficult to control. Parameters such as phosphoric acid concentration, treatment temperature, and immersion time need to be precisely controlled; even slight deviations can easily lead to excessive corrosion of the oxide film or uneven film formation, severely affecting the quality stability of the formed foil. Therefore, a more optimized alternative is urgently needed to overcome the current technological bottlenecks. Summary of the Invention

[0006] The purpose of this application is to provide an aluminum foil formation additive, which aims to solve the technical problems of existing processes that use phosphoric acid solution as the intermediate treatment medium, which have potential adverse effects on subsequent formation processes, are difficult to control, and are prone to excessive corrosion of oxide film or uneven film formation, thereby affecting the quality stability of the formed foil.

[0007] The embodiments of this application are implemented as follows: an aluminum foil forming additive is composed of diethylenetriaminepentamethylenephosphonic acid (DTPMPA), triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:(3-5):(6-8).

[0008] Another objective of this application is a method for high-voltage foil complexation depolarization, comprising:

[0009] After being boiled in water, the aluminum foil undergoes a single formation process under boric acid conditions.

[0010] The aluminum foil after the first formation process is placed in the above-mentioned aluminum foil formation additive for immersion treatment;

[0011] After being soaked, the aluminum foil is heat-treated and then subjected to a secondary formation process under boric acid conditions.

[0012] Another objective of this application is to provide an aluminum electrolytic capacitor comprising a high-voltage forming foil, which is obtained by the aforementioned high-voltage forming foil complexation and depolarization method.

[0013] The aluminum foil forming additive provided in this application uses a composite system of diethylenetriamine pentamethylphosphonic acid, triethanolamine oleic acid soap, and mannose to replace traditional phosphoric acid for intermediate treatment. Through the synergistic effect of each component, it achieves significantly better technical results than traditional processes. Among them, DTPMPA acts as the main corrosion inhibitor and chelating agent; the phosphonic acid groups in its molecule can react with the Al atoms on the aluminum foil surface. 3+The formation of a stable and dense chelated protective film effectively prevents further corrosion of the aluminum foil substrate by the corrosive electrolyte, significantly improving the stability of the alumina dielectric layer and the long-term reliability of the capacitor. It also selectively removes porous hydrated films, avoiding damage to the dense oxide layer and solving the problem of decreased dielectric performance caused by the strong acidity of phosphoric acid, which easily corrodes the dense layer. Triethanolamine oleic acid soap, as a surfactant, auxiliary corrosion inhibitor, and pH adjuster, reduces the surface tension of the treatment solution, promoting the uniform penetration of active ingredients into the depths of the aluminum foil pores. Its amino and hydroxyl groups synergistically improve the continuity of the protective film with DTPMPA, and can also neutralize free acid, stabilize the system pH, and reduce secondary corrosion, overcoming the defects of phosphoric acid, which is prone to localized over-corrosion or residue due to its limited chelating ability. Mannose, as an auxiliary film-forming agent and stabilizer, fills the microscopic defects of the protective film through hydrogen bonding adsorption, making the film layer denser. Simultaneously, it preferentially binds to water molecules to inhibit the hydration reaction of the alumina dielectric layer, solving the problem of decreased capacitance and increased leakage current caused by the hydration reaction of the capacitor.

[0014] In this application embodiment, diethylenetriamine pentamethylphosphonic acid, triethanolamine oleic acid soap, and mannose are compounded in a specific ratio to produce a synergistic effect of "1+1+1>3". This can effectively unclog the blockage caused by excessive hydrated oxide film, remove the porous hydrated film more efficiently, and reduce the damage to the dense layer. Ultimately, this significantly improves the specific capacitance of the etched aluminum foil and the overall performance of the electronic aluminum foil, and prepares a high-performance aluminum electrolytic capacitor that can adapt to harsh working environments. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0016] In order to address the technical problems of existing processes using phosphoric acid solution as the intermediate treatment medium, such as potential adverse effects on subsequent formation processes, difficulty in process control, and easy occurrence of excessive corrosion or uneven film formation of oxide film, thereby affecting the quality stability of the formed foil, this application provides an aluminum foil formation additive. The aluminum foil formation additive is composed of diethylenetriaminepentamethylenephosphonic acid, triethanolamine oleic acid soap, and mannose. The molar ratio of diethylenetriaminepentamethylenephosphonic acid, triethanolamine oleic acid soap, and mannose is 1:(3-5):(6-8), more preferably 1:4:7.

[0017] The total concentration of diethylenetriaminepentamethylenephosphonic acid, triethanolamine oleic acid soap and mannose is 5-10 wt.%, preferably 8 wt.%.

[0018] It is worth noting that by adjusting the ratio of different components, this application essentially finds a balance between film-forming properties, permeability, and hydration inhibition ability to meet the needs of capacitors with different specifications (such as voltage and lifespan requirements).

[0019] The treatment effect for a single component is as follows:

[0020] DTPMPA alone can form a basic phosphonic acid protective film with good corrosion inhibition properties. However, the film density is insufficient, resulting in uneven coverage in complex pit structures, and its inhibitory effect on hydration reactions is limited.

[0021] Using only triethanolamine oleic acid soap: Although it has a certain wetting effect and a slight anti-corrosion effect, it cannot form a strong protective film, and the corrosion inhibition effect is far from meeting the requirements.

[0022] Using only mannose: It has almost no independent film-forming ability, extremely weak corrosion inhibition effect, and can only provide weak and temporary protection.

[0023] The treatment effect of the two-component combination is as follows:

[0024] The combination of DTPMPA and triethanolamine oleic acid soap: DTPMPA forms the main protective film, while triethanolamine oleic acid soap significantly improves the permeability and uniform distribution of DTPMPA in etched pits, ensuring effective protection even in deep pores. This combination exhibits superior corrosion resistance compared to DTPMPA alone and can produce high-performance standard products. However, due to its relatively weak hydration inhibition ability, its long-term service life under high temperature and pressure environments may face limitations.

[0025] The combination of DTPMPA and mannose: DTPMPA forms the main protective film, while mannose fills film defects, enhances its density, and significantly improves the ability to inhibit hydration reactions. Capacitors produced using this combination exhibit excellent lifespan and durability in high-temperature environments above 105°C. However, due to the lack of surfactant, the solution has poor penetration into the etched pits, which may lead to uneven film layers and large fluctuations in initial leakage current parameters.

[0026] The combination of triethanolamine oleic acid soap and mannose: This combination lacks a primary corrosion inhibitor and cannot form a strong chemical protective film. Its positive effects are very limited, and it may only produce some temporary protection through physical adsorption. It cannot be applied to actual production.

[0027] The combined effect of DTPMPA, triethanolamine oleic acid soap, and mannose is as follows: DTPMPA acts as the main agent, forming a strong and tough chemical protective film; triethanolamine oleic acid soap ensures that this film can uniformly and completely cover all surfaces of the aluminum foil, including the deepest and finest etched pits, guaranteeing the consistency of the capacitor's initial performance; mannose is embedded and filled into the phosphonic acid film, eliminating microscopic defects and forming a barrier that significantly delays the hydration aging process of the dielectric layer. This iron triangle combination of main corrosion inhibitor, surfactant, and hydration inhibitor can produce aluminum electrolytic capacitors with ultra-high reliability.

[0028] Compared to phosphoric acid, the aluminum foil forming additive used in this application has significant advantages: the additive can selectively remove the porous hydrated film while protecting the dense layer. Phosphoric acid, being a strong acid, may erode the underlying dense oxide layer when dissolving the porous layer, leading to a decrease in dielectric properties; furthermore, phosphoric acid has limited chelating ability and cannot selectively remove the porous layer, easily causing localized over-corrosion or residue, affecting the stability of subsequent forming processes. The phosphonic acid group (-PO3H2) in this additive molecule can react with aluminum ions (Al2O3) on the aluminum foil surface. 3+ A stable and dense chelated protective film is formed, and the dense oxide layer is not easily damaged due to its stable structure. Replacing phosphoric acid with a compound system of DTPMPA, triethanolamine oleic acid soap, and mannose has the core advantage of producing a synergistic effect of "1+1+1>3" through compounding. This can simultaneously solve the three key problems of film formation, permeation, and hydration resistance, comprehensively surpassing the traditional phosphoric acid process, thereby producing high-performance aluminum electrolytic capacitors that can adapt to harsh working environments.

[0029] This application also provides a method for high-voltage foil complexation depolarization, including:

[0030] After being boiled in water, the aluminum foil undergoes a single formation process under boric acid conditions.

[0031] The aluminum foil after the first formation process is placed in the above-mentioned aluminum foil formation additive for immersion treatment;

[0032] After being soaked, the aluminum foil is heat-treated and then subjected to a secondary formation process under boric acid conditions.

[0033] In the step of immersing the aluminum foil after the first formation treatment in the aluminum foil formation additive described in any one of claims 1-4, the treatment temperature is 40-60°C and the treatment time is 8-15 min; more preferably, the treatment temperature is 50°C and the treatment time is 10 min.

[0034] The step of subjecting the aluminum foil to a boiling water treatment followed by a primary formation treatment under boric acid conditions includes:

[0035] After the aluminum foil was boiled in ultrapure water for 10 minutes, it was subjected to a first formation treatment in a 100 g / L boric acid solution at 88°C.

[0036] The step of subjecting the soaked aluminum foil to heat treatment followed by a secondary formation treatment under boric acid conditions includes:

[0037] The aluminum foil after immersion treatment was heat-treated at 500℃ for 2 minutes, and then subjected to a secondary formation treatment in a 100g / L boric acid solution at 88℃.

[0038] The high-voltage formed foil obtained by the high-voltage formed foil complexation depolarization method provided in the embodiments of this application can be used in the preparation of high-performance aluminum electrolytic capacitors. The preparation method can refer to the prior art, and will not be described in detail here.

[0039] The following detailed description of the aluminum foil formation additive and high-voltage formed foil complexation depolarization method is provided with specific embodiments, as shown below. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0040] Example 1

[0041] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:3:6.

[0042] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in an aluminum foil forming additive with a total concentration of 8 wt.% at 50°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0043] Example 2

[0044] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:8.

[0045] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in an aluminum foil forming additive with a total concentration of 8 wt.% at 50°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0046] Example 3

[0047] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0048] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples that had undergone the first formation were immersed in an aluminum foil forming additive with a total concentration of 8 wt.% at 50°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 10 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0049] Example 4

[0050] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:5:7.

[0051] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in an aluminum foil forming additive with a total concentration of 8 wt.% at 50°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0052] Example 5

[0053] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0054] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in an aluminum foil forming additive with a total concentration of 8 wt.% at 40°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0055] Example 6

[0056] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0057] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples that had undergone the first formation were immersed in an aluminum foil forming additive with a total concentration of 8 wt.% at 60°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0058] Example 7

[0059] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0060] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples that had undergone the first formation were immersed in an aluminum foil forming additive at 50°C with a total concentration of 5 wt.% for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0061] Example 8

[0062] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0063] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples that had undergone the first formation were immersed in an aluminum foil forming additive with a total concentration of 10 wt.% at 50°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0064] Example 9

[0065] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0066] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in an aluminum foil forming additive with a total concentration of 10 wt.% at 50°C for 8 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0067] Example 10

[0068] In this embodiment, the aluminum foil formation additive is composed of DTPMPA, triethanolamine oleic acid soap and mannose, wherein the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose is 1:4:7.

[0069] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in an aluminum foil forming additive with a total concentration of 10 wt.% at 50°C for 15 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the aluminum foil forming additive were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0070] Comparative Example 1

[0071] The etched aluminum foil sample was boiled in ultrapure water for 10 minutes; then it was subjected to a first formation in a 100 g / L boric acid solution at 88°C. After the formation was completed, the sample was washed with ultrapure water. The first-formed sample was then heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C. After the formation was completed, the sample was washed with ultrapure water.

[0072] Comparative Example 2

[0073] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then, they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples treated with the first formation were immersed in a 1.5 wt% phosphoric acid solution at 60°C for 10 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with phosphoric acid were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0074] Comparative Example 3

[0075] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples treated with the first formation were immersed in a 1 wt% phosphoric acid solution at 65°C for 8 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with phosphoric acid were heat-treated at 500°C for 2 minutes; and a second formation was carried out in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0076] Comparative Example 4

[0077] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then, they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the first-formed samples were immersed in 2 wt.% DTPMPA at 60°C for 8 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated in DTPMPA were heat-treated at 500°C for 2 minutes; and a second formation was carried out in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0078] Comparative Example 5

[0079] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then, they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples treated with the first formation were immersed in a 2 wt.% triethanolamine oleic acid soap solution at 60°C for 8 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated with the triethanolamine oleic acid soap solution were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0080] Comparative Example 6

[0081] The etched aluminum foil samples were boiled in ultrapure water for 10 minutes; then, they were subjected to a first formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed; the samples that had undergone the first formation were immersed in 2 wt.% mannose at 60°C for 8 minutes, and the samples were washed with ultrapure water after the immersion was completed; the samples treated in mannose were heat-treated at 500°C for 2 minutes; and then subjected to a second formation in a 100 g / L boric acid solution at 88°C, and the samples were washed with ultrapure water after the formation was completed.

[0082] The samples prepared in Examples 1-10 and Comparative Examples 1-6 were tested according to the industry standard SJ / T 11140-1997 for electrode foils for aluminum electrolytic capacitors. The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] In the preliminary experiments of this application, the following series of studies were conducted on the effects of the type, concentration and ratio of aluminum foil forming additives, the treatment temperature and the treatment time on the complexation and depolarization effect of high-voltage formed foil under the immersion treatment conditions. The experimental conditions and test results are shown in Table 2 below. It should be noted that the following comparative examples are all single-factor variation experiments based on the process of Example 3, including changing the molar ratio of DTPMPA, triethanolamine oleic acid soap and mannose, or changing the total concentration of aluminum foil forming additives, or changing the treatment temperature, or changing the treatment time, or changing the type of aluminum foil forming additives based on the process of Example 3.

[0087] Table 2

[0088]

[0089]

[0090] In summary, as shown in Tables 1-2 above, the embodiments of this application can significantly increase the specific capacity of high-voltage formed foil and reduce dielectric loss by immersing aluminum foil samples in an aluminum foil forming additive obtained by compounding diDTPMPA, triethanolamine oleic acid soap, and mannose under suitable conditions.

[0091] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0092] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An additive for the formation of an aluminum foil, characterized in that, The aluminum foil formation additive is composed of diethylene triamine penta-methylene phosphonic acid, triethanolamine oleic acid soap and mannose, and the molar ratio of the diethylene triamine penta-methylene phosphonic acid, triethanolamine oleic acid soap and mannose is 1:(3-5):(6-8).

2. The aluminum foil formation additive according to claim 1, characterized by, The molar ratio of the diethylene triamine penta-methylene phosphonic acid, triethanolamine oleic acid soap and mannose is 1:4:

7.

3. The aluminum foil formation additive according to claim 1, characterized by, The total concentration of the diethylene triamine penta-methylene phosphonic acid, triethanolamine oleic acid soap and mannose is 5-10 wt.%.

4. The aluminum foil formation additive according to claim 1, characterized by, The total concentration of the diethylene triamine penta-methylene phosphonic acid, triethanolamine oleic acid soap and mannose is 8 wt.%.

5. A method of high pressure formation foil complex depolarization characterized by, Comprising: After the aluminum foil is treated by boiling, the aluminum foil is subjected to a first formation treatment under boric acid conditions; The aluminum foil subjected to the first formation treatment is immersed in the aluminum foil formation additive according to any one of claims 1-4 for soaking treatment; The aluminum foil subjected to the soaking treatment is subjected to a second formation treatment under boric acid conditions after heat treatment.

6. The method of high pressure formation foil complex depolarization of claim 5, wherein, In the step of immersing the aluminum foil subjected to the first formation treatment in the aluminum foil formation additive according to any one of claims 1-4 for soaking treatment, the treatment temperature is 40-60°C, and the treatment time is 8-15 min.

7. The method of high pressure formation foil complex depolarization of claim 5, wherein, In the step of immersing the aluminum foil subjected to the first formation treatment in the aluminum foil formation additive according to claim 1 or 2 for soaking treatment, the treatment temperature is 50°C, and the treatment time is 10 min.

8. The method of high pressure formation foil complex depolarization of claim 5, wherein, The step of treating the aluminum foil by boiling and then subjecting the aluminum foil to a first formation treatment under boric acid conditions comprises: After the aluminum foil is subjected to boiling treatment in boiling ultrapure water for 10 min, the aluminum foil is subjected to a first formation treatment in a 100 g / L boric acid solution at a temperature of 88°C.

9. The method of high pressure formation foil complex depolarization of claim 5, wherein, The step of treating the aluminum foil subjected to the soaking treatment by heat treatment and then subjecting the aluminum foil to a second formation treatment under boric acid conditions comprises: After the aluminum foil subjected to the soaking treatment is subjected to heat treatment at a temperature of 500°C for 2 min, the aluminum foil is subjected to a second formation treatment in a 100 g / L boric acid solution at a temperature of 88°C.

10. An aluminum electrolytic capacitor characterized by The aluminum electrolytic capacitor comprises a high-voltage formation foil, and the high-voltage formation foil is obtained by the high-voltage formation foil complex depolarization method according to any one of claims 5-9.

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