A method for producing a solid aluminum electrolytic capacitor with low leakage current
By introducing a two-stage oxide film process of "repairing carbonization and then repairing", the oxide film at the edge of the anode foil is optimized, which solves the problem of high leakage current in solid aluminum electrolytic capacitors, improves the performance and reliability of the capacitors, and is suitable for the preparation of solid aluminum electrolytic capacitors with low leakage current.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG HUAXIAN NEW MATERIAL TECH CO LTD
- Filing Date
- 2026-04-09
- Publication Date
- 2026-06-09
AI Technical Summary
In the existing technology, there is a lack of clear and detailed process methods for burr treatment on the edge of the anode foil after cutting solid aluminum electrolytic capacitors, which leads to high leakage current and affects the reliability and service life of the capacitor.
A two-stage oxide film optimization process of "repair carbonization-repair" is adopted, which includes repair carbonization treatment, re-repair treatment, cleaning and drying. Through high current and low current anodic repair, the oxide film at the edge of the anode foil is optimized and leakage current is reduced.
It significantly reduces leakage current, improves the overall performance and reliability of capacitors, extends service life, and also has good process compatibility and environmental friendliness, reducing production costs.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of solid electrolytic capacitor technology, and more specifically, to a method for preparing a solid aluminum electrolytic capacitor with low leakage current. Background Technology
[0002] In the design and manufacture of solid aluminum electrolytic capacitors, conductive polymer materials are commonly used as the solid electrolyte to replace the electrolyte in traditional liquid aluminum electrolytic capacitors in order to obtain excellent high-frequency performance. This material change significantly reduces the equivalent series resistance (ESR), showing a clear technical advantage, especially at higher frequencies. However, the anode foil in the internal structure of the capacitor is usually etched to form a porous structure with a high specific surface area. After cutting, the edges of the foil are prone to microscopic burrs or sharp protrusions. If these burrs are not properly treated, they may not only cause local tip discharge under the action of an electric field, leading to increased leakage current and deterioration of electrical performance, but also pose a risk of mechanically piercing the interlayer insulating medium (such as electrolytic paper or polymer coating), and in severe cases, even cause short circuits between electrodes, directly affecting the reliability and service life of the capacitor.
[0003] To address this issue, existing technologies have recognized the importance of edge treatment of the cut electrode foil. Currently, some technical solutions propose grinding the cut edges of the anode and cathode foils to eliminate burrs and smooth the edges, thereby reducing the risk of electrical and mechanical failures caused by edge defects. This type of treatment helps improve the contact state between the electrode and electrolyte interface and reduces local electric field concentration, which is significant for improving the overall performance and quality control of solid-state electrolytic capacitors. However, existing publicly available information often lacks clear and detailed explanations regarding the specific process methods, implementation stages, and their connection with subsequent processes (such as formation treatment). For example, whether specific formation processes should be used in conjunction with the grinding process before and after carbonization is still unclear, and a unified and detailed process specification has not yet been formed. Therefore, how to effectively and controllably achieve refined edge treatment while ensuring the inherent electrical properties of the electrodes remains a key aspect that needs further optimization and clarification in the current manufacturing of solid-state aluminum electrolytic capacitors.
[0004] In view of this, the present invention is proposed. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing a solid aluminum electrolytic capacitor with low leakage current. By introducing a two-stage oxide film optimization process of "repair carbonization-repair", the technical problem of high leakage current in solid aluminum electrolytic capacitors is solved, significantly improving the performance and reliability of the capacitor and extending its service life.
[0006] This invention is implemented as follows: This invention provides a method for preparing a solid aluminum electrolytic capacitor with low leakage current, comprising the following steps: drawing out electrodes from the cut anode foil and cathode foil by riveting and winding them to form a capacitor element; performing a repair carbonization treatment on the element, and then performing a re-repair treatment; after the re-repair is completed, the element is sequentially subjected to impregnation polymerization, encapsulation, and aging to obtain a solid aluminum electrolytic capacitor with low leakage current. The re-repair process involves sequentially performing high-current anodic repair, low-current anodic repair, cleaning, and drying on the carbonized elements.
[0007] In an optional embodiment, the repair solution for the carbonization repair treatment is an aqueous solution of ammonium adipate with a mass fraction of 5-20%.
[0008] In an optional embodiment, the carbonization temperature is 200-280°C and the time is 2-4 hours.
[0009] In an optional embodiment, the anolyte in the re-repair treatment is an aqueous solution of ammonium dihydrogen phosphate with a mass fraction of 1‰-10‰, and the repair temperature is 60-85℃.
[0010] In an optional implementation, the high-current anode repair is performed in TV characteristic mode, with a current input of 5-15mA, a withstand voltage input of 90%Vf, and a repair time of 150-180s.
[0011] In an optional implementation, the low-current anode repair is performed in leakage current mode, with a current input of 0.4-0.9mA, a withstand voltage input of 95%Vf, and a repair time of 180s-600s.
[0012] In an optional embodiment, the cleaning solution in the re-repair process is pure water, the cleaning temperature is 35-65℃, and the cleaning time is 10-20 minutes.
[0013] In an optional embodiment, the drying temperature is 85-135°C and the drying time is 60-120 min.
[0014] In an optional embodiment, the polymer used for the impregnation polymerization is poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid), and the viscosity of the polymer is controlled at 15-50 mPa·s.
[0015] In an optional embodiment, the impregnation polymerization is carried out at a temperature of 25-40°C for 15-25 minutes.
[0016] The present invention has the following beneficial effects: This invention provides a method for preparing a low-leakage-current solid aluminum electrolytic capacitor by introducing a two-stage oxide film optimization process of "repair carbonization-re-repair". This method effectively improves the density and self-healing ability of the Al2O3 dielectric film, significantly reducing the leakage current of the capacitor. The optimized oxide film can suppress interface defects and ion migration, thereby improving the overall performance and reliability of the capacitor and extending its service life. In addition, high-current anodic repair and low-current anodic repair treatments further enhance the stability of the dielectric film and reduce the failure rate of the capacitor during use. This method improves upon existing production processes, requires no complex equipment or technology, has good process compatibility, and is suitable for large-scale production. By reducing leakage current and improving capacitor reliability, this method also reduces product return rates and maintenance costs, improving overall economic efficiency. At the same time, the use of environmentally friendly treatment solutions and processes reduces environmental impact and meets the requirements of green manufacturing. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0018] This invention provides a method for preparing a low-leakage-current solid aluminum electrolytic capacitor, comprising the following steps: S1. The cut anode foil and cathode foil are riveted together to lead out the electrodes and then wound to form a capacitor element; It should be noted that the anode foil includes, but is not limited to, high-dielectric nanocomposite oxide film anode foil.
[0019] S2. Perform carbonization repair treatment on the element, and then perform further repair treatment; In an optional embodiment, the repair solution for the carbonization treatment is an ammonium adipate aqueous solution with a mass fraction of 5-20%; the carbonization temperature is 200-280℃ and the time is 2-4h.
[0020] The re-repair process involves sequentially performing high-current anodic repair, low-current anodic repair, cleaning, and drying on the carbonized elements. The inventors creatively utilize the weak acidity of ammonium dihydrogen phosphate and low-current formation repair to perform anodic foil repair on the normally carbonized elements of wound solid capacitors, thereby reducing leakage current and increasing the reliability of the oxide film.
[0021] In an optional embodiment, the anolyte in the re-repair treatment is an aqueous solution of ammonium dihydrogen phosphate with a mass fraction of 1‰-10‰, and the repair temperature is 60-85℃.
[0022] In an optional implementation, the high-current anode repair and low-current anode repair employ a "multi-channel aluminum foil TV characteristic / leakage current / electrolyte intelligent testing system DC800V20mA". The high-current anode repair is performed in TV characteristic mode, with a current input of 5-15mA, a withstand voltage input set to 90%Vf, and a repair time of 150-180s. The low-current anode repair is performed in leakage current mode, with a current input of 0.4-0.9mA, a withstand voltage input set to 95%Vf, and a repair time of 180s-600s.
[0023] In an optional embodiment, the cleaning solution in the re-repair treatment is pure water, the cleaning temperature is 35-65℃, and the cleaning time is 10-20 min; the drying temperature is 85-135℃, and the drying time is 60-120 min.
[0024] S3. After the repair is completed, the substrate undergoes impregnation polymerization, encapsulation, and aging in sequence to obtain a solid aluminum electrolytic capacitor with low leakage current.
[0025] In an optional embodiment, the polymer used for the impregnation polymerization includes, but is not limited to, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS), wherein the viscosity of the polymer is controlled at 15-50 mPa·s; the impregnation polymerization temperature is 25-40°C and the time is 15-25 min.
[0026] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0027] Example 1 This embodiment provides a method for preparing a low-leakage-current solid aluminum electrolytic capacitor, including the following steps: S1. The cut anode foil and cathode foil are riveted together to lead out the electrodes and wound to form a 16V 330uF capacitor element; S2. The element is repaired by carbonization treatment, and then the carbonized element is repaired in TV mode at 60℃ and 3% ammonium adipate with preset 10mA, 23V, 180s. It is also repaired in leakage current mode at 80℃ and 3‰ ammonium dihydrogen phosphate with preset 0.5mA, 22V, 180s. It is then rinsed with pure water at 60℃ for 10min and dried at 125℃ for 60min. S3. After the repair is completed, the substrate undergoes impregnation polymerization, encapsulation, and aging in sequence to obtain a solid aluminum electrolytic capacitor with low leakage current.
[0028] Example 2 This embodiment provides a method for preparing a low-leakage-current solid aluminum electrolytic capacitor, including the following steps: S1. The cut anode foil and cathode foil are riveted together to lead out the electrodes and wound to form a 16V 330uF capacitor element; S2. The element is repaired by carbonization treatment, and then the carbonized element is repaired in TV mode at 60℃ and 3‰ ammonium dihydrogen phosphate with preset 10mA, 23V, 180s. It is then repaired in leakage current mode at 80℃ and 3‰ ammonium dihydrogen phosphate with preset 0.5mA, 22V, 180s. It is then rinsed with pure water at 60℃ for 10min and dried at 125℃ for 60min. S3. After the repair is completed, the substrate undergoes impregnation polymerization, encapsulation, and aging in sequence to obtain a solid aluminum electrolytic capacitor with low leakage current.
[0029] Example 3 This embodiment provides a method for preparing a low-leakage-current solid aluminum electrolytic capacitor, including the following steps: S1. The cut anode foil and cathode foil are riveted together to lead out the electrodes and wound to form a 16V 330uF capacitor element; S2. The element is repaired by carbonization treatment, and then the carbonized element is repaired in TV mode at 80℃ and 3‰ ammonium dihydrogen phosphate with preset 10mA, 23V, 180s. It is also repaired in leakage current mode at 80℃ and 3‰ ammonium dihydrogen phosphate with preset 0.5mA, 22V, 180s. It is then rinsed with pure water at 60℃ for 10min and dried at 125℃ for 60min. S3. After the repair is completed, the substrate undergoes impregnation polymerization, encapsulation, and aging in sequence to obtain a solid aluminum electrolytic capacitor with low leakage current.
[0030] Comparative Example 1 This comparative example provides a method for preparing a low-leakage-current solid aluminum electrolytic capacitor, including the following steps: S1. The cut anode foil and cathode foil are riveted together to lead out the electrodes and wound to form a 16V 330uF capacitor element; S2. The element is repaired and carbonized, and then the carbonized element is repaired in the leakage current mode at 80℃ and 3‰ ammonium dihydrogen phosphate at 0.5mA and 22V for 3min, followed by rinsing with pure water at 60℃ for 10min and drying at 125℃ for 60min. S3. After the repair is completed, the substrate undergoes impregnation polymerization, encapsulation, and aging to obtain a solid aluminum electrolytic capacitor.
[0031] Test case The solid aluminum electrolytic capacitors prepared in Examples 1-3 and Comparative Example 1 were subjected to performance testing, including the following steps: the leakage current value after small-current anodizing was recorded as LC1; after cleaning and drying, a leakage current test was performed again. The test time was fixed at 180s, the temperature was 80℃, the test solution was an aqueous solution of ammonium dihydrogen phosphate with a mass fraction of 3‰, the current input was 0.5mA, the withstand voltage input was set to 95%Vf, and the leakage current value was recorded as LC2. The results are shown in Table 1.
[0032] Table 1. Performance test results of solid aluminum electrolytic capacitors.
[0033]
[0034] The performance test results of Examples 1 to 3 and Comparative Example 1 show that the dual repair process combining TV mode repair and leakage current mode repair can significantly reduce the leakage current of solid aluminum electrolytic capacitors. The leakage current values (LC2) in Examples 1, 2, and 3 were 68 μA, 66 μA, and 61 μA, respectively, all significantly lower than the first test value (LC1). The changes in ΔLC were 18 μA, 12 μA, and 13 μA, respectively, indicating that the repair treatment effectively reduced the leakage current level of the capacitor. In contrast, Comparative Example 1 only underwent leakage current mode repair without TV mode repair; its LC2 was 82 μA, almost identical to LC1's 83 μA, with a ΔLC of only 1 μA, indicating that the single repair mode has limited effect on improving leakage current.
[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a solid aluminum electrolytic capacitor with low leakage current, characterized in that, Includes the following steps: The cut anode foil and cathode foil are riveted together to lead out the electrodes and wound to form a capacitor element; the element is repaired and carbonized, and then repaired again. After the repair is completed, the substrate undergoes impregnation polymerization, encapsulation and aging in sequence to obtain a solid aluminum electrolytic capacitor with low leakage current. The re-repair process involves sequentially performing high-current anodic repair, low-current anodic repair, cleaning, and drying on the carbonized elements.
2. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The repair solution used for the carbonization treatment is an ammonium adipate aqueous solution with a mass fraction of 5-20%.
3. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The carbonization temperature is 200-280℃, and the time is 2-4 hours.
4. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The anolyte used in the re-repair treatment is an aqueous solution of ammonium dihydrogen phosphate with a mass fraction of 1‰-10‰, and the repair temperature is 60-85℃.
5. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The high-current anode repair is performed in TV characteristic mode, with a current input of 5-15mA, a withstand voltage input of 90%Vf, and a repair time of 150-180s.
6. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The low-current anode repair is performed in leakage current mode, with a current input of 0.4-0.9mA, a withstand voltage input of 95%Vf, and a repair time of 180s-600s.
7. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The cleaning solution used in the re-repair process is pure water, the cleaning temperature is 35-65℃, and the cleaning time is 10-20 minutes.
8. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The drying temperature is 85-135℃, and the drying time is 60-120 minutes.
9. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The polymer used in the impregnation polymerization is poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid), and the viscosity of the polymer is controlled at 15-50 mPa·s.
10. The method for preparing a low-leakage-current solid aluminum electrolytic capacitor according to claim 1, characterized in that, The impregnation polymerization is carried out at a temperature of 25-40°C for 15-25 minutes.