Production process of high specific capacity medium and high voltage electrode foil

Abstract

The present invention discloses a production process for high-specific-capacity medium- and high-voltage electrode foil, which relates to the technical field of aluminum foil processing. The basic process flow is: raw materials → pretreatment → primary variable-current multi-stage etching and surface expansion treatment → secondary chemical etching and surface expansion treatment → chemical washing → water washing → pure water washing → drying → finished product. The multi-stage etching and surface expansion equipment frame is equipped with a power supply array corresponding to the aluminum foil etching box; the positive electrode of the power supply is connected to the aluminum foil; the negative electrode of the power supply is respectively connected to two special-shaped graphite electrodes, the tops of the special-shaped graphite electrodes are connected to the anti-corrosion copper busbar; the aluminum foil drive roller is arranged below the special-shaped graphite electrode and connected to the shielding plate of the special-shaped graphite electrode. A multi-stage pore-forming device is used. By using special-shaped graphite electrode plates, the variable current power supply problem is achieved, solving the problems of combined pores and overly shallow pores caused by power outages in the original process, thereby effectively increasing the pore density and the specific capacity of the etched foil.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum foil processing, and in particular relates to a production process for medium- and high-voltage electrode foils with high specific volume. Background Art

[0002] As the industry develops, the need for miniaturization of electronic components is increasing. For aluminum electrolytic capacitors, achieving this requires increasing the unit capacitance of the positive aluminum foil, which serves as the capacitor's anode. The capacitor's principle formula shows that the dielectric constant ε is a constant. Therefore, to increase the capacitance Cap, it is necessary to increase the surface area S of the electrode or reduce the thickness d of the dielectric.

[0003] At present, domestic electrode foil high processing adopts single-stage hole-making device, such as Figure 1 As shown, the aluminum foil passes through the middle of two straight graphite electrode plates 001. During operation, two power supplies are connected. Due to the different connections of the positive and negative poles of the two power supplies, the currents applied to the two sides of the aluminum foil are different, which causes different corrosion and affects the quality of the aluminum foil. In addition, the distance between the two straight graphite electrode plates is about 20 cm, the impedance is large, and the energy consumption is high. The current of one power supply is between 4500 and 5500 A. When such a structure is in operation, power failure will cause problems such as parallel holes and holes that are too shallow, affecting efficiency and quality. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a production process for medium and high voltage electrode foils with high specific volume, which can produce medium and high voltage electrode foils with high specific volume and good strength, improve production efficiency, and effectively improve product quality level.

[0005] The production process of the high-capacity medium- and high-voltage electrode foil of the present invention adopts an electrochemical treatment method to achieve an increase in the surface area of ​​the aluminum foil;

[0006] The basic process flow is as follows:

[0007] Raw materials → pre-treatment → primary variable current multi-stage corrosion expansion treatment → secondary chemical corrosion expansion treatment → chemical washing → water washing → pure water washing → drying → finished product.

[0008] 1. Pretreatment: Purpose: Remove oil and oxides from the surface of aluminum foil; Solution: 10-25% H2SO4; Temperature: 40-70°C; Treatment time: 1-5 minutes;

[0009] 2. Single-stage variable current multi-stage corrosion expansion treatment: Purpose: Using a special waveform intelligent power supply, by repeatedly turning the power on and off, to form a certain number of corrosion holes with a certain aperture on the aluminum foil surface; Solution: 15-25% H2SO4 + 3-10% HCl + Additive A; Temperature: 60-80°C; Treatment time: 1-5 minutes; Current density: 0-0.5A / cm2

[0010] 3. Secondary chemical etching and surface expansion treatment: Purpose: To enlarge the diameter of the corrosion holes formed by the primary etching and surface expansion; Solution: 1-10% HCl + Additive B; Temperature: 80-90°C; Treatment time: 15-20 minutes;

[0011] 4. Chemical washing: Purpose: To remove aluminum powder and chloride ions remaining on the surface of corroded aluminum foil; Solution: 0.5-10% HNO3; Temperature: 40-60°C; Treatment time: 1-3 minutes;

[0012] 5. Water washing: Purpose: The purpose of each level of water washing is to remove the acid remaining on the surface of the aluminum foil after it comes out of the acid tank; Solution: tap water; Temperature: room temperature; Processing time: 1 to 5 minutes;

[0013] 6. Pure water washing: Purpose: to remove the acid and chloride ions remaining on the surface of the corroded aluminum foil; Solution: pure water; Temperature: room temperature; Processing time: 10 to 30 minutes;

[0014] 7. Drying: Purpose: Drying aluminum foil; Temperature: 200-400℃; Processing time: 1-3min; After the above-mentioned treatments, the surface area of ​​the aluminum foil is expanded, and the electrostatic capacitance per unit area is increased.

[0015] The equipment for the variable current multi-stage corrosion expansion treatment in step 2 includes a frame, an aluminum foil corrosion box, an anti-corrosion copper busbar, a special-shaped graphite electrode, and an aluminum foil transmission roller; the several aluminum foil corrosion boxes are arranged below the frame; an array of power supplies corresponding to the aluminum foil corrosion boxes is provided on the frame; the positive pole of the power supply is connected to the aluminum foil; the negative pole of the power supply is connected to the two special-shaped graphite electrodes respectively, and the top of the special-shaped graphite electrode is connected to the anti-corrosion copper busbar; the aluminum foil transmission roller is arranged below the special-shaped graphite electrode and connected to the shielding plate of the special-shaped graphite electrode.

[0016] Preferably, the spacing between the special-shaped graphite electrodes is about 5 cm, which has low resistance, energy saving and environmental protection.

[0017] Preferably, the inner side of the special-shaped graphite electrode is a sloped structure with a narrow bottom and a wide top, which is suitable for variable current aluminum foil processing and can improve the specific volume and strength of the aluminum foil.

[0018] Preferably, the current of the power supply is 2000-2200A, which divides the original single power supply into different levels, improves the stability of the power supply current, saves the energy consumption of the power supply, and reduces the cost.

[0019] The present invention adopts multi-stage pore treatment technology to increase the pore density of the corrosion foil and adopts a special waveform intelligent power supply to reduce the phenomenon of pore merging.

[0020] This invention utilizes a multi-stage pore-forming device and, through the use of shaped graphite electrode plates, achieves variable current powering, resolving the problems of combined pores and shallow pores caused by power outages in the previous process. This effectively increases pore density and the specific volume of the etched foil. Furthermore, the multi-stage pore-forming device significantly increases reaction speed and production efficiency. The second stage utilizes chemical etching, reducing equipment and production costs and effectively reducing pollutant emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] For ease of explanation, the present invention is described in detail with reference to the following specific embodiments and accompanying drawings:

[0022] Figure 1 It is a structural diagram of the background technology;

[0023] Figure 2 It is a structural schematic diagram of the present invention;

[0024] Figure 3 for Figure 2 A schematic diagram of the structure of the two-stage pore-forming device;

[0025] In the figure: frame 1, aluminum foil corrosion box 2, anti-corrosion copper bus 3, special-shaped graphite electrode 4, aluminum foil transmission roller 5, power supply 6. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below using specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0027] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, the accompanying drawings only show structures and / or processing steps closely related to the solutions according to the present invention, while other details that are not closely related to the present invention are omitted.

[0028] The principle formula for capacitors shows that the dielectric constant ε is a constant. Therefore, to increase the electrostatic capacitance Cap, it is necessary to increase the surface area S of the electrode or reduce the thickness d of the dielectric. Therefore, this specific embodiment uses electrochemical treatment to increase the surface area of ​​the aluminum foil.

[0029] The basic process flow of this specific embodiment is as follows:

[0030] Raw materials → pre-treatment → primary variable current multi-stage corrosion expansion treatment → secondary chemical corrosion expansion treatment → chemical washing → water washing → pure water washing → drying → finished product.

[0031] 1. Pre-treatment:

[0032] Purpose: Remove oil and oxides from the surface of aluminum foil; Solution: 10-25% H2SO4; Temperature: 40-70°C; Treatment time: 1-5 minutes;

[0033] 2. One-time variable current multi-stage corrosion expansion treatment:

[0034] Purpose: Using a special waveform intelligent power supply, by repeatedly turning the power on and off, to form a certain number of corrosion holes with a certain pore size on the surface of the aluminum foil; Solution: 15-25% H2SO4 + 3-10HCl + Additive A;

[0035] Temperature: 60-80°C; Treatment time: 1-5 min; Current density: 0-0.5 A / cm2

[0036] 3. Secondary chemical etching and surface expansion treatment: Purpose: To enlarge the diameter of the corrosion holes formed by the primary etching and surface expansion; Solution: 1-10% HCl + Additive B; Temperature: 80-90°C; Treatment time: 15-20 minutes;

[0037] 4. Chemical washing:

[0038] Purpose: To remove aluminum powder and chloride ions remaining on the surface of corroded aluminum foil; Solution: 0.5-10% HNO3; Temperature: 40-60°C; Treatment time: 1-3 minutes;

[0039] 5. Washing:

[0040] Purpose: The purpose of each level of water washing is to remove the acid remaining on the surface of the aluminum foil after it comes out of the acid tank; Solution: tap water; Temperature: room temperature; Treatment time: 1 to 5 minutes;

[0041] 6.Pure water washing:

[0042] Purpose: To remove residual acid and chloride ions on the surface of corroded aluminum foil; Solution: Pure water; Temperature: Room temperature; Treatment time: 10-30 minutes;

[0043] 7. Drying:

[0044] Purpose: Drying aluminum foil; Temperature: 200-400℃; Processing time: 1-3 minutes;

[0045] After the above-mentioned treatments, the surface area of ​​the aluminum foil is expanded, and the electrostatic capacitance per unit area is increased.

[0046] like Figure 2 and Figure 3 As shown, the equipment for the variable current multi-stage corrosion expansion treatment in step 2 includes a frame 1, an aluminum foil corrosion box 2, an anti-corrosion copper busbar 3, a special-shaped graphite electrode 4, and an aluminum foil transmission roller 5; the several aluminum foil corrosion boxes 2 are arranged below the frame 1; an array of power supplies 6 corresponding to the aluminum foil corrosion boxes 2 is provided on the frame 1; the positive pole of the power supply 6 is connected to the aluminum foil; the negative pole of the power supply 6 is respectively connected to the two special-shaped graphite electrodes 4, and the top of the special-shaped graphite electrode 4 is connected to the anti-corrosion copper busbar 3; the aluminum foil transmission roller 5 is arranged below the special-shaped graphite electrode 4 and connected to the shielding plate of the special-shaped graphite electrode 4.

[0047] Furthermore, the spacing between the special-shaped graphite electrodes 4 is about 5 cm, which has low resistance and is energy-saving and environmentally friendly.

[0048] Furthermore, the inner side of the special-shaped graphite electrode 4 is a sloped structure with a narrow bottom and a wide top, which is suitable for variable current aluminum foil processing and can improve the specific volume and strength of the aluminum foil.

[0049] Furthermore, the current of the power supply 6 is 2000-2200A, which divides the original single power supply into different levels, improves the stability of the power supply current, saves the energy consumption of the power supply, and reduces the cost.

[0050] The principle behind this specific embodiment is the use of a multi-stage pore-forming device and shaped graphite electrode plates, enabling variable current application. This solves the problems of combined pores and shallow pores caused by power outages in the previous process, effectively increasing pore density and the specific volume of the etched foil. Furthermore, the multi-stage pore-forming device significantly increases reaction speed and production efficiency, boosting production speed from the current domestic standard of 1.50 m / min to 5.00 m / min. This more than triples production efficiency and improves technical standards by nearly 15%.

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0052] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A production process for medium and high voltage electrode foil with high specific capacity, characterized by: The process is as follows: (1) Pre-treatment: Purpose: Remove oil and oxides from the surface of aluminum foil; solution: 10-25% H2SO4; temperature : 40~70℃; processing time: 1~ 5min; (2) Single-stage variable current multi-stage corrosion expansion treatment: Purpose: Using a special waveform intelligent power supply, by repeatedly turning the power on and off, to form a certain number of corrosion holes with a certain aperture on the surface of the aluminum foil; Solution: 15-25% H2SO4 + 3-10% HCl + additive A; Temperature: 60-80°C; Treatment time: 1-5 min; Current density: 0-0.5 A / cm2; (3) Secondary chemical etching and surface expansion treatment: Purpose: to enlarge the diameter of the corrosion holes formed by the primary etching and surface expansion; Solution: 1-10% HCl + Additive B; Temperature: 80-90°C; Treatment time: 15-20 min; (4) Chemical washing: Purpose: To remove the aluminum powder and chloride ions remaining on the surface of corroded aluminum foil; Solution: 0.5-10% HNO3; Temperature: 40-60°C; Treatment time: 1-3 minutes; (5) Water washing: Purpose: The purpose of water washing is to remove the acid remaining on the surface of the aluminum foil after it comes out of the acid tank; Solution: tap water; temperature : Room temperature; Processing time: 1 to 5 minutes; (6) Pure water washing: Purpose: To remove the acid and chloride ions remaining on the surface of corroded aluminum foil; Solution: pure water; temperature : Room temperature; Processing time: 10-30min; (7) Drying: Purpose: Drying aluminum foil; Temperature: 200-400°C; Treatment time: 1-3 minutes; After the above-mentioned treatments, the surface area of ​​the aluminum foil is expanded, and the electrostatic capacitance per unit area is increased; The equipment for the variable current multi-stage corrosion expansion treatment in step (2) includes an anti-corrosion copper bus, a special-shaped graphite electrode and an aluminum foil transmission roller; the top of the special-shaped graphite electrode is connected to the anti-corrosion copper bus; the aluminum foil transmission roller is arranged below the special-shaped graphite electrode and connected to the shielding plate of the special-shaped graphite electrode to realize variable current powering; The inner side of the special-shaped graphite electrode is a sloped structure with a narrow bottom and a wide top, which is suitable for variable current aluminum foil processing and can improve the specific volume and strength of the aluminum foil.

2. The production process of high-capacity medium- and high-voltage electrode foil according to claim 1, characterized in that: The equipment for the variable current multi-stage corrosion expansion treatment in step (2) further includes a rack and a plurality of aluminum foil corrosion boxes; the plurality of aluminum foil corrosion boxes are arranged below the rack; an array of power supplies corresponding to the aluminum foil corrosion boxes is provided on the rack; the positive pole of the power supply is connected to the aluminum foil; and the negative pole of the power supply is connected to two special-shaped graphite electrodes respectively.

3. The production process of high-capacity medium- and high-voltage electrode foil according to claim 2, characterized in that: The distance between the special-shaped graphite electrodes is 5 cm.

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