阅读说明：本技术 耐大压降和大纹波电流电容 (Large voltage drop and large ripple current resistant capacitor ) 是由 欧德虎 江国栋 于 2019-10-23 设计创作，主要内容包括：本发明涉及耐大压降和大纹波电流电容,包括化成箔,所述化成箔包括正箔与负箔,所述正箔的制备工艺包括以下步骤：S1.采用中高压腐蚀铝箔,并对中高压腐蚀铝箔进行前处理；S2.使用化成液对中高压腐蚀铝箔进行三级化成处理,化成液温度＜60℃,化成电压为1-250V,每级化成时间为2-15min,每级电流密度为1-5A/m2；S3.将三级化成箔放入75-85℃纯水中进行煮沸处理,煮沸时间为5-10min；S4.重复S2步骤对三级化成箔进行五级化成处理；S5.对五级化成箔进行后处理,制得初成品；S6.使用纯水对初成品进行喷淋清洗后置于烘箱烘干,制得正箔成品。本发明具有提高电容耐大压降与大纹波电流的效果。(The invention relates to a capacitor with large voltage drop resistance and large ripple current, which comprises formed foils, wherein the formed foils comprise positive foils and negative foils, and the preparation process of the positive foils comprises the following steps: s1, adopting a medium-high pressure corrosion aluminum foil, and pretreating the medium-high pressure corrosion aluminum foil; s2, carrying out three-stage formation treatment on the medium-high pressure corrosion aluminum foil by using a formation liquid, wherein the temperature of the formation liquid is less than 60 ℃, the formation voltage is 1-250V, the formation time of each stage is 2-15min, and the current density of each stage is 1-5A/m 2; s3, putting the three-stage formed foil into pure water at the temperature of 75-85 ℃ for boiling treatment, wherein the boiling time is 5-10 min; s4, repeating the step S2 to carry out five-level formation processing on the three-level formed foil; s5, carrying out post-treatment on the five-level formed foil to obtain a primary finished product; s6, spraying and cleaning the primary finished product by using pure water, and then placing the primary finished product in an oven for drying to obtain a positive foil finished product. The invention has the effect of improving the resistance of the capacitor to large voltage drop and large ripple current.)

1. Resistant big voltage drop and big ripple current capacitance, including forming the foil, its characterized in that: the formed foil comprises a positive foil and a negative foil, and the preparation process of the positive foil comprises the following steps:

s1, adopting a medium-high pressure corrosion aluminum foil, and pretreating the medium-high pressure corrosion aluminum foil;

s2, carrying out three-stage formation treatment on the medium-high pressure corrosion aluminum foil by using a formation liquid, wherein the temperature of the formation liquid is less than 60 ℃, the formation voltage is 1-250V, and each stage of formation timeThe interval is 2-15min, and the current density of each stage is 1-5A/m²；

S3, putting the three-stage formed foil into pure water at the temperature of 75-85 ℃ for boiling treatment, wherein the boiling time is 5-10 min;

s4, repeating the step S2 to carry out five-level formation processing on the three-level formed foil;

s5, carrying out post-treatment on the five-level formed foil to obtain a primary finished product;

s6, spraying and cleaning the primary finished product by using pure water, and then placing the primary finished product in an oven for drying to obtain a positive foil finished product.

2. The capacitor according to claim 1, characterized in that: the preparation method of the medium-high pressure corrosion aluminum foil comprises the following steps: firstly, placing the optical foil in a corrosive liquid for direct current corrosion treatment, wherein the corrosion temperature is 70-80 ℃, the corrosion time is 450-550s, and the corrosive liquid comprises the following components in parts by mass: 70-80% of phosphoric acid solution, 3-6% of acetic acid solution, 2-7% of nitric acid solution, 0.2-1% of polyaspartic acid solution and the balance of water.

3. The capacitor according to claim 1, characterized in that: the thickness of the medium-high pressure corrosion aluminum foil is 75-120 um.

4. The capacitor according to claim 1, characterized in that: the pretreatment process in S1 is: heating the medium-high pressure corrosion aluminum foil at the temperature of 500-550 ℃ for 3-5min, and soaking the medium-high pressure corrosion aluminum foil in an oxalic acid solution with the concentration of 1-4% for 5-15 min.

5. The large voltage drop and large ripple current tolerant capacitor of claim 4, wherein: the temperature of the oxalic acid solution is less than 40 ℃.

6. The capacitor according to claim 1, characterized in that: the chemical solutions in S2 and S4 are both ammonium pentaborate solutions or boric acid solutions or a mixture of both.

7. The capacitor according to claim 1, characterized in that: the post-processing procedure in S5 is: soaking the five-grade formed foil in 2-6% ammonium citrate solution for 3-10 min.

8. The large voltage drop and large ripple current tolerant capacitor of claim 7, wherein: the temperature of the ammonium citrate solution is 25-45 ℃.

9. The capacitor according to claim 1, characterized in that: the preparation method of the negative foil comprises the following steps: the optical foil is subjected to chemical conversion treatment after being subjected to alternating current corrosion treatment with the frequency of 10-20Hz, and the chemical conversion voltage is 1-50V.

10. The capacitor according to claim 1, characterized in that: the capacitor is formed by combining and connecting 4 layers of foil and 8 layers of paper.

Technical Field

The invention relates to the technical field of electronic products, in particular to a capacitor with large voltage drop resistance and large ripple current.

Background

The formed foil is a product formed by forming a layer of oxide film on the surface of a special high-purity aluminum foil through electrochemical or chemical corrosion and electrochemical forming. The formed foil may be divided into a positive foil and a negative foil according to the purpose. Positive foil, negative foil and electrolytic paper are the main materials for making electrolytic capacitors (also referred to as capacitors for short) which are one of the important components of electronic components, and the number of the electrolytic capacitors accounts for the second place of the whole capacitor industry, and is second only to ceramic capacitors, which is a great importance in the electronic component industry. The electrolytic capacitor is mainly used for filtering, energy storage and conversion, signal bypass, coupling, time constant elements in a control circuit and the like.

The medium-high voltage formed foil for the aluminum electrolytic capacitor belongs to a special electronic material, is one of basic industries, is a weak link of the Chinese electronic industry, and is brought into the industry of national key development and support. The high-grade medium-high pressure formed foil is a key material for replacing the basic industry imported by the Chinese electronic industry. As the formed foil material for producing the aluminum electrolytic capacitor in China has a late starting point and is developed slowly, domestic products mainly depend on import and are in short supply at present, and thus, the medium-high voltage formed foil product in production has wide market prospect.

Disclosure of Invention

The invention aims to provide a capacitor resistant to large voltage drop and large ripple current.

The technical purpose of the invention is realized by the following technical scheme: the capacitor with high voltage drop resistance and large ripple current comprises formed foils, wherein the formed foils comprise positive foils and negative foils, and the preparation process of the positive foils comprises the following steps:

s1, adopting a medium-high pressure corrosion aluminum foil, and pretreating the medium-high pressure corrosion aluminum foil;

s2, carrying out three-stage formation treatment on the medium-high pressure corrosion aluminum foil by using a formation liquid, wherein the temperature of the formation liquid is less than 60 ℃, the formation voltage is 1-250V, the formation time of each stage is 2-15min, and the current density of each stage is 1-5A/m²；

S3, putting the three-stage formed foil into pure water at the temperature of 75-85 ℃ for boiling treatment, wherein the boiling time is 5-10 min;

s4, repeating the step S2 to carry out five-level formation processing on the three-level formed foil;

s5, carrying out post-treatment on the five-level formed foil to obtain a primary finished product;

s6, spraying and cleaning the primary finished product by using pure water, and then placing the primary finished product in an oven for drying to obtain a positive foil finished product.

By adopting the technical scheme, in the preparation process, amorphous gamma-Al on the surface of the aluminum foil is corroded at medium and high pressure₂O₃The film gradually transforms into crystalline gamma-Al₂O₃Film, crystalline gamma-Al₂O₃Films and amorphous gamma-Al₂O₃Compared with the film, the internal resistance and the formed electric quantity of the film are greatly reduced, so that the performance of the positive foil for resisting large voltage drop and large ripple current is improved;

pretreating the medium-high pressure corrosion aluminum foil, wherein the pretreatment is used for improving the hydration resistance of the aluminum foil;

amorphous gamma-Al formed during formation₂O₃Film is transformed into crystalline gamma-Al₂O₃During film formation, amorphous gamma-Al₂O₃The three-stage formed foil is placed in pure water for boiling treatment, which is favorable for opening the crack closed part of the oxide film and releasing oxygen in the cracked holes, so that the cracked holes are fully exposed, and the cracked holes can continue to grow to form crystalline gamma-Al in the subsequent forming process₂O₃Film, thereby increasing crystalline gamma-Al₂O₃The structural compactness of the film layer is improved, so that the physical and chemical properties of the film layer are improved;

and carrying out post-treatment on the five-level formed foil, wherein the post-treatment is used for forming a protective film on the surface of the five-level formed foil, so that the hydration resistance of the finished positive foil is improved.

The invention is further configured to: the preparation method of the medium-high pressure corrosion aluminum foil comprises the following steps: placing the optical foil in a corrosive liquid for direct current corrosion treatment, wherein the corrosion temperature is 70-80 ℃, the corrosion time is 450-550s, and the corrosive liquid comprises the following components in parts by mass: 70-80% of phosphoric acid solution, 3-6% of acetic acid solution, 2-7% of nitric acid solution, 0.2-1% of polyaspartic acid solution and the balance of water.

By adopting the technical scheme, the phosphoric acid and acetic acid solution react with aluminum on the surface of the aluminum foil, so that the aluminum foil can be favorably promoted to be perforated;

after the hole is formed on the aluminum foil, the nitric acid solution continuously corrodes the aluminum foil, so that the aperture of the corrosion hole on the aluminum foil is enlarged to be larger than 0.05um, and the formation effect of the subsequent formation process is improved;

the polyaspartic acid solution is used for relieving the corrosion rate of the aluminum foil and avoiding forming a larger corrosion cavity due to too fast corrosion of the aluminum foil, so that the uniformity of the corrosion cavity of the aluminum foil is improved, and the subsequent formation effect is improved;

the phosphoric acid solution, the acetic acid solution, the nitric acid solution and the polyaspartic acid solution are mixed according to a proper proportion, and the structural compactness of the corrosion cavity is improved.

The invention is further configured to: the thickness of the medium-high pressure corrosion aluminum foil is 75-120 um.

By adopting the technical scheme, the thickness of the medium-high pressure corrosion aluminum foil is too thick or too thin, and the subsequent formation effect can be influenced.

The invention is further configured to: the pretreatment process in S1 is: firstly, heating the medium-high pressure corrosion aluminum foil at the temperature of 500-550 ℃ for 3-5min, and then soaking the medium-high pressure corrosion aluminum foil in oxalic acid solution with the concentration of 1-4% for 5-15 min.

By adopting the technical scheme, the medium-high pressure corrosion aluminum foil is heated at the temperature of 500-550 ℃, so that a layer of thinner crystalline gamma-Al is formed on the surface of the medium-high pressure corrosion aluminum foil₂O₃A film, thereby increasing the specific volume of the positive foil finished product;

then placing the medium-high pressure corrosion aluminum foil in oxalic acid solution with the concentration of 1-4% for soaking, and obtaining the carboxyl and the crystalline gamma-Al in oxalic acid molecules₂O₃Film surfaceHydroxyl group of (2) to occupy crystalline gamma-Al₂O₃Active sites on the surface of the film, thereby crystallizing gamma-Al₂O₃The surface of the film is protected to improve the crystallization of gamma-Al₂O₃Hydration resistance of the film, avoidance of crystalline gamma-Al₂O₃The membrane is degraded to affect the voltage drop resistance and ripple current resistance.

The invention is further configured to: the temperature of the oxalic acid solution is less than 40 ℃.

The invention is further configured to: the chemical solutions in S2 and S4 are both ammonium pentaborate solutions or boric acid solutions or a mixture of both.

The invention is further configured to: the post-processing procedure in S5 is: soaking the five-grade formed foil in 2-6% ammonium citrate solution for 3-10 min.

By adopting the technical scheme, the five-grade formed foil is soaked in an ammonium citrate solution, and the ammonium citrate solution mainly has the following two effects that the hydroxy carboxylic acid in ① molecules is adsorbed on the crystalline gamma-Al with positive charges₂O₃The surface of the film is provided with carboxyl and crystalline gamma-Al under the action of an electric field₂O₃The molecule group on the surface of the film generates occupying reaction, thereby crystallizing gamma-Al₂O₃The film has a protective effect, thereby increasing the crystallization of gamma-Al₂O₃② citrate ions have weak acidity and can remove crystal gamma-Al₂O₃Hydration of oxide on the surface of the film, thereby improving the crystallization of gamma-Al₂O₃Specific volume of the film.

The invention is further configured to: the temperature of the ammonium citrate solution is 25-45 ℃.

The invention is further configured to: the preparation method of the negative foil comprises the following steps: the optical foil is subjected to chemical conversion treatment after being subjected to alternating current corrosion treatment with the frequency of 10-20Hz, and the chemical conversion voltage is 1-50V.

By adopting the technical scheme, the optical foil is placed under the alternating current electric wave with the frequency of 10-20Hz for corrosion, and the alternating current corrosion is favorable for expanding the corrosion cavity of the optical foil to be more than 0.05um, so that the corrosion effect of the optical foil is improved, and the subsequent formation effect is improved.

The invention is further configured to: the capacitor is formed by combining and connecting 4 layers of foil and 8 layers of paper.

In conclusion, the beneficial technical effects of the invention are as follows:

1. amorphous gamma-Al on the surface of the aluminum foil during the process of preparing the positive foil₂O₃The film gradually transforms into crystalline gamma-Al₂O₃Film, crystalline gamma-Al₂O₃The internal resistance and the formed electric quantity of the film are greatly reduced, so that the performance of the positive foil for resisting large voltage drop and large ripple current is improved; the three-level formed foil is placed in pure water for boiling treatment, which is beneficial to improving the structural compactness of the crystalline gamma-Al 2O3 film layer, thereby improving the physical and chemical properties of the crystalline gamma-Al 2O3 film layer; the post-treatment is used for forming a protective film on the surface of the five-level formed foil, so that the hydration resistance of the finished positive foil is improved;

2. the polyaspartic acid solution is used for relieving the corrosion rate of the aluminum foil and avoiding forming a larger corrosion cavity due to too fast corrosion of the aluminum foil, so that the uniformity of the corrosion cavity of the aluminum foil is improved, and the subsequent formation effect is improved;

3. the negative foil is prepared by alternating current corrosion, so that the corrosion cavity of the optical foil is favorably expanded to be more than 0.05um, the corrosion effect of the optical foil is improved, and the subsequent formation effect is improved.

Detailed Description