Method for manufacturing anode foil and method for manufacturing aluminum electrolytic capacitor

Abstract

The invention discloses a manufacturing method of an anode foil and a manufacturing method of an aluminum electrolytic capacitor, and the manufacturing method of the anode foil comprises the following steps: providing a first aluminum foil which is divided into a coating area and two blank areas in the width direction, the coating area is located between the two blank areas in the width direction of the first aluminum foil; the two opposite surfaces of the coating area of the first aluminum foil are both continuously coated with aluminum powder slurry in the length direction of the first aluminum foil, and drying and sintering are conducted; performing formation on the coating area to obtain a laminated foil; and cutting the laminated foil into a plurality of anode foils, wherein each anode foil comprises an anode foil main body formed by the coating area and an anode tab formed by the blank area. According to the manufacturing method of the anode foil, the capacity of a capacitor is improved, the size of the capacitor is reduced, the internal resistance of the capacitor is reduced, and the method has the advantages of high reliability, high production efficiency and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitor manufacturing, and in particular to a method for manufacturing an anode foil and an aluminum electrolytic capacitor. Background Art

[0002] The aluminum electrolytic capacitor in the related art can only increase the specific capacitance of the anode foil by increasing the anode foil facing area and increasing the expansion multiple, which limits the increase in the capacity of the aluminum electrolytic capacitor. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for manufacturing an anode foil, which helps to increase the capacitor capacity, reduce the capacitor volume, and reduce the capacitor internal resistance, and has the advantages of high reliability and high production efficiency.

[0004] The invention also provides a method for manufacturing an aluminum electrolytic capacitor.

[0005] To achieve the above object, a method for manufacturing an anode foil is provided according to an embodiment of a first aspect of the present invention. The method for manufacturing an anode foil comprises the following steps:

[0006] Providing a first aluminum foil, wherein the first aluminum foil is divided into a coating area and two blank areas in a width direction, and the coating area is located between the two blank areas in the width direction of the first aluminum foil;

[0007] Continuously coating aluminum powder slurry on two opposite surfaces of the coating area of ​​the first aluminum foil along the length direction of the first aluminum foil, and performing drying and sintering;

[0008] Performing chemical forming on the coating area to obtain a laminated foil;

[0009] The laminated foil is cut into a plurality of anode foils, each of which includes an anode foil main body formed by the coating region and an anode tab formed by the blank region.

[0010] The method for manufacturing the anode foil according to the embodiment of the present invention is helpful to increase the capacity of the capacitor, reduce the volume of the capacitor, and reduce the internal resistance of the capacitor, and has the advantages of high reliability and high production efficiency.

[0011] In addition, the method for manufacturing the anode foil according to the above embodiment of the present invention may also have the following additional technical features:

[0012] According to one embodiment of the present invention, the formation voltage when the coating area is formed is 600-1200V.

[0013] According to one embodiment of the present invention, the first aluminum foil is a plain foil or a corroded foil, the width of the first aluminum foil is 150-250 mm, the width of the coated area is 120-220 mm, the width of the blank area is 10-20 mm, the thickness of the first aluminum foil is 20-60 μm, and the thickness of the laminated foil is 100-200 μm.

[0014] According to one embodiment of the present invention, the aluminum powder slurry includes aluminum powder and a solvent, the solvent is one or more of ethanol, pinene alcohol, ethylene glycol, polyethylene glycol, and diethylene glycol butyl ether, the average particle size of the aluminum powder is 1-10 microns, and the mass ratio of the aluminum powder to the solvent is 1:1.5-1:2.5.

[0015] According to an embodiment of the second aspect of the present invention, a method for manufacturing an aluminum electrolytic capacitor is provided, and the method for manufacturing an aluminum electrolytic capacitor comprises the following steps:

[0016] Providing a first aluminum foil and a second aluminum foil, wherein the first aluminum foil is divided into a coating area and two blank areas in a width direction, and the coating area is located between the two blank areas in the width direction of the first aluminum foil;

[0017] Continuously coating aluminum powder slurry on two opposite surfaces of the coating area of ​​the first aluminum foil along the length direction of the first aluminum foil, and performing drying and sintering;

[0018] Performing chemical forming on the coating area to obtain a laminated foil;

[0019] Cutting the laminated foil into a plurality of anode foils, wherein the anode foil comprises an anode foil main body formed by the coating area and an anode tab formed by the blank area, and cutting the second aluminum foil into a plurality of cathode foils, wherein the cathode foil comprises a cathode foil main body and a cathode tab;

[0020] Alternately stacking a plurality of the anode foils and a plurality of the cathode foils with electrolytic paper sandwiched between each adjacent anode foil and cathode foil, and processing them into a core package;

[0021] The core package is coated with an aluminum-plastic film to form a soft package, and an electrolyte is injected into the soft package and the soft package is sealed.

[0022] The method for manufacturing an aluminum electrolytic capacitor according to an embodiment of the present invention is helpful to increase the capacitor capacity, reduce the capacitor volume, and reduce the capacitor internal resistance, and has the advantages of high reliability and high production efficiency.

[0023] According to one embodiment of the present invention, after injecting electrolyte into the soft package and sealing it, the following steps are also included:

[0024] Performing an aging treatment on the soft package;

[0025] Puncture the soft bag in a vacuum environment to discharge gas and excess electrolyte;

[0026] The soft bag is sealed again.

[0027] In addition, the method for manufacturing the aluminum electrolytic capacitor according to the above embodiment of the present invention may also have the following additional technical features:

[0028] According to an embodiment of the present invention, the number of the cathode foils in the core package is one more than the number of the anode foils.

[0029] According to one embodiment of the present invention, the formation voltage when the coating area is formed is 600-1200V.

[0030] According to one embodiment of the present invention, the first aluminum foil is a plain foil or a corroded foil and has a width of 150-250 mm, the width of the coated area is 120-220 mm, the width of the blank area is 10-20 mm, the thickness of the first aluminum foil is 20-60 μm, the thickness of the laminated foil is 100-200 μm, the second aluminum foil is a plain foil or a corroded foil and has a width of 150-250 mm, and the thickness of the second aluminum foil is 10-30 μm.

[0031] According to one embodiment of the present invention, the aluminum powder slurry includes aluminum powder and a solvent, the solvent is one or more of ethanol, pinene alcohol, ethylene glycol, polyethylene glycol, and diethylene glycol butyl ether, the average particle size of the aluminum powder is 1-10 microns, and the mass ratio of the aluminum powder to the solvent is 1:1.5-1:2.5.

[0032] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0034] Figure 1 Schematic diagram of the partial structure of the first aluminum foil in the method for manufacturing the anode foil according to an embodiment of the present invention.

[0035] Figure 2 Schematic diagram of the structure of an anode foil according to a method for manufacturing an anode foil of an embodiment of the present invention.

[0036] Figure 3 Schematic diagram of the structure of the cathode foil of the method for manufacturing an aluminum electrolytic capacitor according to an embodiment of the present invention.

[0037] Figure 4Schematic diagram of the structure of a core package of an aluminum electrolytic capacitor manufacturing method according to an embodiment of the present invention.

[0038] Figure 5 Schematic diagram of the structure of a soft package of an aluminum electrolytic capacitor manufacturing method according to an embodiment of the present invention.

[0039] Figure 6 is a flow chart of a method for manufacturing an anode foil according to an embodiment of the present invention.

[0040] Figure 7 is a flow chart of a method for manufacturing an aluminum electrolytic capacitor according to an embodiment of the present invention.

[0041] Figure numerals: first aluminum foil 10, coated area 11, blank area 12, anode foil 100, anode foil body 110, anode tab 120, cathode foil 200, cathode foil body 210, cathode tab 220, core package 300, electrolytic paper 310, tape 320, soft package 400, aluminum-plastic film 410, anode lead terminal 420, cathode lead terminal 430. DETAILED DESCRIPTION

[0042] This application is based on the inventor's discovery and understanding of the following facts and problems:

[0043] The aluminum electrolytic capacitor in the related art can only increase the specific capacitance of the anode foil by increasing the anode foil facing area and increasing the expansion multiple, which limits the increase in the capacity of the aluminum electrolytic capacitor.

[0044] Through a high-temperature sintering process, the high-purity spherical aluminum powder coated on the surface of the high-purity core layer aluminum foil is fully combined with the core layer aluminum foil, and finally a powder layer with a three-dimensional porous structure is obtained on the surface of the core layer aluminum foil. The specific capacity of the laminated foil prepared by this high-temperature sintering process is related to the thickness of the high-purity spherical aluminum powder coating, which significantly improves the capacity of the aluminum electrolytic capacitor and can break through the limitation of the related technology of using the surface expansion method to increase the capacity of the aluminum electrolytic capacitor.

[0045] Aluminum electrolytic capacitors are mostly cylindrical and take up a lot of space. In order to save space and reduce the volume, aluminum electrolytic capacitors on circuit boards need to be flat.

[0046] The flat-shaped aluminum electrolytic capacitor in the related art adopts a flat elliptical structure, and its core package is formed by winding. On the one hand, the number of pole ears that can be led out of the winding structure is small, resulting in a relatively high internal resistance of the aluminum electrolytic capacitor. On the other hand, the laminated foil coated with aluminum powder is prone to aluminum powder falling off due to excessive curvature during the winding process.

[0047] Some aluminum electrolytic capacitors form laminated foil by coating aluminum powder on aluminum foil, which is then cut into anode foil and stacked with cathode foil to form a core package. However, the aluminum foil is intermittently coated with aluminum powder in the length direction to form a blank area between two coated areas, and the blank area is cut to form the anode foil. This method has low coating efficiency due to the discontinuous coating area, and the cutting method is complex, resulting in low cutting efficiency. In addition, the coated aluminum powder needs to be formed. Due to the discontinuous coating area, the formation efficiency is also relatively low, resulting in low overall production efficiency.

[0048] In addition, the aluminum electrolytic capacitor in the related art is provided with an explosion-proof valve to prevent excessive pressure. However, once the explosion-proof valve is opened, the electrolyte inside the aluminum electrolytic capacitor will leak, which will not only cause the aluminum electrolytic capacitor to fail quickly, but also damage the circuit board and other components.

[0049] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0051] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] A method for manufacturing an anode foil according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0053] like Figure 1 , Figure 2 and Figure 6 As shown, the method for manufacturing an anode foil according to an embodiment of the present invention comprises the following steps:

[0054] A first aluminum foil 10 is provided. The first aluminum foil 10 is divided into a coating area 11 and two blank areas 12 in the width direction. The coating area 11 is located between the two blank areas 12 in the width direction of the first aluminum foil 10.

[0055] Aluminum powder slurry is continuously coated on two opposite surfaces of the coating area 11 of the first aluminum foil 10 along the length direction of the first aluminum foil 10, and then dried and sintered;

[0056] Forming the coated area 11 to obtain a laminated foil;

[0057] The laminated foil is cut into a plurality of anode foils 100 . The anode foil 100 includes an anode foil main body 110 formed by a coating region 11 and an anode tab 120 formed by a blank region 12 .

[0058] Specifically, if Figure 1 As shown, the coating area 11 can be cut into two anode foil bodies 110 in the width direction of the first aluminum foil 10, and each anode foil body 110 is respectively connected to an anode tab 120 formed by an adjacent blank area 12. The anode foil 100 can be cut by die cutting to improve cutting consistency and cutting efficiency.

[0059] According to the manufacturing method of the anode foil of the embodiment of the present invention, aluminum powder slurry is coated on the coating area 11, and dried, sintered and chemically formed to fully combine the aluminum powder with the aluminum foil, and an aluminum powder layer with a three-dimensional porous structure is formed on the surface of the aluminum foil. The specific volume of the formed laminated foil is related to the thickness of the spherical aluminum powder layer, which can break through the limitation of the method of increasing the specific volume by the surface expansion method in the related art, and significantly improve the capacity of the aluminum electrolytic capacitor.

[0060] Moreover, by cutting the laminated foil into multiple anode foils, it is not only convenient to form a flat capacitor to reduce the occupied space, but also compared with the core package structure using a winding structure in the related technology, it can increase the number of tabs that can be led out and reduce the internal resistance of the capacitor. It can also prevent aluminum powder from falling off due to excessive winding curvature, thereby improving reliability.

[0061] In addition, aluminum powder slurry is continuously coated on two opposite surfaces of the coating area 11 of the first aluminum foil 10 along the length direction of the first aluminum foil 10, so that the coating area 11 is located between the two blank areas 12 in the width direction of the first aluminum foil 10, and the anode foil 100 includes an anode foil body 110 formed by the coating area 11 and an anode tab 120 formed by the blank area 12. Compared with the method of intermittently coating aluminum powder in the length direction and forming a blank area between the two coating areas, the aluminum powder coating process can be carried out continuously, which can not only improve the coating efficiency, but also make the formed aluminum powder coating area continuous, which is not only convenient for continuous formation and improves the formation efficiency. For example, in the formation process, only the coating area 11 can be immersed in the formation liquid and voltage can be applied, while the blank area 12 is not immersed in the formation liquid. Moreover, since the coating area 11 and the blank area 12 are continuous in the length direction of the first aluminum foil 10, the cutting process of the anode foil 100 is simpler and more efficient.

[0062] Therefore, the method for manufacturing the anode foil according to the embodiment of the present invention is helpful to increase the capacity of the capacitor, reduce the volume of the capacitor, and reduce the internal resistance of the capacitor, and has the advantages of high reliability and high production efficiency.

[0063] A method for manufacturing an anode foil according to a specific embodiment of the present invention will be described below with reference to the accompanying drawings.

[0064] Specifically, the formation voltage when the coating area 11 is formed is 600-1200V. Specifically, the formation process is actually an anodic oxidation process. Aluminum will undergo an oxidation reaction with the formation liquid under pressure to generate an aluminum oxide film. The higher the formation voltage, the thicker the generated aluminum oxide film, which reduces the specific surface area of ​​the aluminum foil or laminated foil and reduces the specific volume. Whether it is aluminum foil or laminated foil, the higher the formation voltage, the lower the capacity. By adopting a higher formation voltage, the rated voltage of the capacitor can be increased, and due to the use of laminated foil coated with aluminum powder, the capacitor can still have a good capacity while having a higher rated voltage.

[0065] Optionally, the first aluminum foil 10 is a plain foil or an etched foil, the width of the first aluminum foil 10 is 150-250 mm, the width of the coating area 11 is 120-220 mm, the width of the blank area 12 is 10-20 mm, the thickness of the first aluminum foil 10 is 20-60 μm, and the thickness of the laminated foil is 100-200 μm. Preferably, the width of the first aluminum foil 10 is 200 mm, the width of the coating area 11 is 170 mm, and the width of the blank area 12 is 15 mm. In this way, the first aluminum foil 10, the coating area 11, and the blank area 12 can have reasonable sizes, which is convenient for forming an anode foil of a suitable size and for cutting the first aluminum foil 10.

[0066] More specifically, the aluminum powder slurry includes aluminum powder and a solvent, wherein the solvent is one or more of ethanol, terpineol, ethylene glycol, polyethylene glycol, and diethylene glycol butyl ether, the average particle size of the aluminum powder is 1-10 microns, and the mass ratio of the aluminum powder to the solvent is 1:1.5-1:2.5. This facilitates the coating and attachment of the aluminum powder, facilitates the formation of a three-dimensional porous structure, and further facilitates the improvement of the specific volume.

[0067] According to the manufacturing method of the anode foil of the embodiment of the present invention, the preparation method of the aluminum powder slurry is not limited and can be any preparation method in the art. Specifically, the aluminum powder slurry can be prepared by the following method: select aluminum powder with an average particle size of 1-10 microns, mix the aluminum powder and the solvent at a mass ratio of 1:1.5-1:2.5, and stir for 1-10 hours to obtain the aluminum powder slurry.

[0068] Reference below Figure 1-Figure 7 The method for manufacturing an aluminum electrolytic capacitor according to an embodiment of the present invention is described. The method for manufacturing an aluminum electrolytic capacitor according to an embodiment of the present invention comprises the following steps:

[0069] A first aluminum foil 10 and a second aluminum foil are provided, wherein the first aluminum foil 10 is divided into a coating area 11 and two blank areas 12 in a width direction, and the coating area 11 is located between the two blank areas 12 in the width direction of the first aluminum foil 10;

[0070] Aluminum powder slurry is continuously coated on two opposite surfaces of the coating area 11 of the first aluminum foil 10 along the length direction of the first aluminum foil 10, and then dried and sintered;

[0071] Forming the coated area 11 to obtain a laminated foil;

[0072] The laminated foil is cut into a plurality of anode foils 100, wherein the anode foil 100 includes an anode foil main body 110 formed by a coating area 11 and an anode tab 120 formed by a blank area 12; the second aluminum foil is cut into a plurality of cathode foils 200, wherein the cathode foil 200 includes a cathode foil main body 210 and a cathode tab 220;

[0073] A plurality of anode foils 100 and a plurality of cathode foils 200 are alternately stacked and an electrolytic paper 310 is sandwiched between each adjacent anode foil 100 and cathode foil 200, and processed into a core package 300;

[0074] The core package 300 is coated with an aluminum-plastic film 410 to form a soft package 400, and an electrolyte is injected into the soft package 400 and sealed.

[0075] It can be understood by those skilled in the art that the above steps are only necessary steps to solve the technical problem of the present invention, and those skilled in the art can perform other operations between the steps according to actual needs. For example, the tabs can be shaped before the core package 300 is coated with aluminum-plastic film.

[0076] According to the method for manufacturing an aluminum electrolytic capacitor of an embodiment of the present invention, aluminum powder slurry is coated on the coating area 11, and dried, sintered and chemically formed to fully combine the aluminum powder with the aluminum foil, and an aluminum powder layer with a three-dimensional porous structure is formed on the surface of the aluminum foil. The specific volume of the formed laminated foil is related to the thickness of the spherical aluminum powder layer, which can break through the limitation of the method of increasing the specific volume by the surface expansion method in the related art, and significantly improve the capacity of the aluminum electrolytic capacitor.

[0077] Furthermore, by cutting the laminated foil into multiple anode foils and stacking the multiple anode foils and multiple cathode foils into a core package, it is not only convenient to form a flat capacitor to reduce the occupied space, but also compared with the core package structure using a winding structure in the related art, it can increase the number of tabs that can be led out and reduce the internal resistance of the capacitor. It can also prevent aluminum powder from falling off due to excessive winding curvature, thereby improving reliability.

[0078] In addition, aluminum powder slurry is continuously coated on two opposite surfaces of the coating area 11 of the first aluminum foil 10 along the length direction of the first aluminum foil 10, so that the coating area 11 is located between the two blank areas 12 in the width direction of the first aluminum foil 10, and the anode foil 100 includes an anode foil body 110 formed by the coating area 11 and an anode tab 120 formed by the blank area 12. Compared with the method of intermittently coating aluminum powder in the length direction and forming a blank area between the two coating areas, the aluminum powder coating process can be carried out continuously, which can not only improve the coating efficiency, but also make the formed aluminum powder coating area continuous, which is not only convenient for continuous formation and improves the formation efficiency. For example, in the formation process, only the coating area 11 can be immersed in the formation liquid and voltage can be applied, while the blank area 12 is not immersed in the formation liquid. Moreover, since the coating area 11 and the blank area 12 are continuous in the length direction of the first aluminum foil 10, the cutting process of the anode foil 100 is simpler and more efficient.

[0079] The method for manufacturing an aluminum electrolytic capacitor according to an embodiment of the present invention is helpful to increase the capacitor capacity, reduce the capacitor volume, and reduce the capacitor internal resistance, and has the advantages of high reliability and high production efficiency.

[0080] After injecting electrolyte into the soft package 400 and sealing it, the following steps are also included:

[0081] Perform aging treatment on soft pack 400;

[0082] Puncture the soft pack 400 in a vacuum environment to discharge gas and excess electrolyte;

[0083] The soft package 400 is sealed again.

[0084] Specifically, the aging process will generate a large amount of gas, causing the soft pack 400 to swell, affecting the capacitor capacity and internal resistance. By puncturing the soft pack 400 under vacuum conditions to discharge the gas and excess electrolyte and sealing it again, the internal resistance of the aluminum electrolytic capacitor product can be ensured to be low. Since there is no gas inside the soft pack capacitor, the product has good cycle stability and a long service life. Compared with the method of setting an explosion-proof valve, it can avoid leakage during pressure relief and damage to circuit boards and other components.

[0085] Advantageously, the number of cathode foils 200 in the core package 300 is one more than the number of anode foils 100. In other words, cathode foils 200 are provided on both sides of each anode foil 100. This allows the capacity of the anode foil 100 to be fully utilized, effectively increasing the capacity of the capacitor.

[0086] Optionally, the formation voltage when the coating area 11 is formed is 600-1200V. Specifically, the formation process is actually the process of anodizing. Aluminum will undergo oxidation reaction with the formation liquid under pressurized conditions to generate an aluminum oxide film. The higher the formation voltage, the thicker the generated aluminum oxide film, which reduces the specific surface area of ​​the aluminum foil or laminated foil and reduces the specific volume. Whether it is aluminum foil or laminated foil, the higher the formation voltage, the lower the capacity. By adopting a higher formation voltage, the rated voltage of the capacitor can be increased, and due to the use of laminated foil coated with aluminum powder, the capacitor can still have a good capacity while having a higher rated voltage.

[0087] Specifically, the first aluminum foil 10 is a plain foil or an etched foil and has a width of 150-250 mm, the width of the coating area 11 is 120-220 mm, the width of the blank area 12 is 10-20 mm, the thickness of the first aluminum foil 10 is 20-60 μm, the thickness of the laminated foil is 100-200 μm, the second aluminum foil is a plain foil or an etched foil and has a width of 150-250 mm, and the thickness of the second aluminum foil is 10-30 μm. Here, it is preferred that the width of the first aluminum foil 10 is 200 mm, the width of the coating area 11 is 170 mm, the width of the blank area 12 is 15 mm, and the width of the second aluminum foil is 200 mm. In this way, the first aluminum foil 10, the second aluminum foil, the coating area 11 and the blank area 12 have reasonable sizes, which is convenient for forming anode foil and cathode foil of suitable sizes, and for cutting the first aluminum foil 10 and the second aluminum foil.

[0088] More specifically, the aluminum powder slurry includes aluminum powder and a solvent, wherein the solvent is one or more of ethanol, terpineol, ethylene glycol, polyethylene glycol, and diethylene glycol butyl ether, the average particle size of the aluminum powder is 1-10 microns, and the mass ratio of the aluminum powder to the solvent is 1:1.5-1:2.5. This facilitates the coating and attachment of the aluminum powder, facilitates the formation of a three-dimensional porous structure, and further facilitates the improvement of the specific volume.

[0089] According to the manufacturing method of the anode foil of the embodiment of the present invention, the preparation method of the aluminum powder slurry is not limited and can be any preparation method in the art. Specifically, the aluminum powder slurry can be prepared by the following method: select aluminum powder with an average particle size of 1-10 microns, mix the aluminum powder and the solvent at a mass ratio of 1:1.5-1:2.5, and stir for 1-10 hours to obtain the aluminum powder slurry.

[0090] Specifically, the anode foil 100 , the cathode foil 200 and the electrolytic paper 310 may be bonded together into the core package 300 by means of an adhesive tape 320 .

[0091] The anode tab 120 may be connected to an anode lead terminal 420 , and the cathode tab 220 may be connected to a cathode lead terminal 430 .

[0092] The following describes methods for manufacturing aluminum electrolytic capacitors according to some specific embodiments of the present invention.

[0093] Two rolls of aluminum foil are processed and customized, namely the first aluminum foil 10 and the second aluminum foil, the first aluminum foil 10 has a thickness of 20-60 microns, and the second aluminum foil has a thickness of 10-30 microns;

[0094] Aluminum powder slurry is coated on both sides of the coating area 11 in the center of the first aluminum foil 10 along the length direction of the aluminum foil and dried, and the blank areas 12 on both sides of the first aluminum foil 10 are kept blank. The width of the coating area 11 is 170 mm, and the width of the blank areas 12 on both sides is 15 mm. After high-temperature sintering, a rough laminated foil product with a thickness of 100-200 μm is obtained. The coating area 11 of the rough laminated foil product is formed at a voltage of 600-1200V (during the formation, only the coating area is immersed in the formation liquid and an electric field is applied, and the non-coating area is not pressurized or the non-coating area is protected and not immersed in the formation liquid) to obtain a laminated foil; due to the continuous coating and double-sided blanking, the composite aluminum foil obtained by sintering after coating with aluminum powder can be continuously formed; the formation voltage is 600-1200V.

[0095] The obtained laminated foil is die-cut into an anode foil 100 having a rectangular sheet structure, and the anode foil 100 includes an anode foil body 110 formed by a coating area 11 and an anode tab 120 formed by a blank area 12. The second aluminum foil is die-cut into a cathode foil 200 having a rectangular sheet structure using the same die. Except for the difference in thickness, the shape and area of ​​the die-cut cathode foil 200 are exactly the same as those of the anode foil 100;

[0096] The obtained plurality of anode foils 100 and cathode foils 200 are processed together with electrolytic paper into a core package 300 of a laminated structure by a laminating machine;

[0097] The obtained core package 300 is sequentially subjected to the steps of ear cutting and shaping, ultrasonic spot welding, aluminum-plastic film forming, core package top and side sealing, vacuum drying, liquid injection, primary sealing, aging, puncturing the soft package to separate gas and excess electrolyte, and sealing again to obtain a soft package liquid aluminum electrolytic capacitor product.

[0098] The following is a comparison between some specific embodiments of the present invention and methods in related technologies:

[0099] Embodiment 1:

[0100] 1) Process and customize two rolls of etched aluminum foil with a width of 200 mm, the thickness of the first aluminum foil is 30 microns, and the thickness of the second aluminum foil is 20 microns;

[0101] 2) using a transfer coater to sequentially coat aluminum powder slurry (selecting aluminum powder with an average particle size of 3.5 μm and adding it to a planetary mixer at a mass ratio of aluminum powder: polyethylene glycol = 1:1.93, and vacuum stirring for 5 hours to obtain the aluminum powder slurry) on the front and back sides of the central coating area of ​​the first aluminum foil obtained in step 1, and then drying, keeping the blank areas on both sides of the first aluminum foil blank, the width of the coating area is 170 mm, and the width of the blank areas on both sides is 15 mm, controlling the aluminum powder slurry to overlap the coating areas on the front and back sides of the first aluminum foil, and obtaining a laminated foil rough product with a thickness of 130 μm after segmented high-temperature sintering, and forming the coating area of ​​the laminated foil rough product at 700 V to obtain a laminated foil;

[0102] 3) The laminated foil obtained in step 2 is die-cut into an anode foil having a rectangular sheet structure, wherein the lower rectangular area of ​​the anode foil has an aluminum powder coating layer on both sides, and the upper anode tab has no coating layer, such as Figure 2 The second aluminum foil obtained in step 1 is die-cut into a cathode foil having a rectangular sheet structure using the same mold, as shown in FIG. Figure 3 As shown;

[0103] 4) Processing the 30 anode foils and 31 cathode foils obtained in step 3 together with 30 μm thick electrolytic paper into a 055×59×88 mm laminated core package using a laminating machine, such as Figure 4 As shown;

[0104] 5) The laminated core package obtained in step 4 is sequentially subjected to the steps of ear cutting and shaping, ultrasonic spot welding, aluminum-plastic film forming, core package top and side sealing, vacuum drying, liquid injection, primary sealing, aging, puncturing the soft package to separate gas and excess electrolyte, and resealing to obtain a 06×60×90 mm soft package liquid aluminum electrolytic capacitor product, such as Figure 5 shown.

[0105] Embodiment 2:

[0106] 1) Process and customize two rolls of etched aluminum foil with a width of 200 mm, the thickness of the first aluminum foil is 30 microns, and the thickness of the second aluminum foil is 20 microns;

[0107] 2) using a transfer coater to sequentially coat aluminum powder slurry (selecting aluminum powder with an average particle size of 3.5 μm and adding it to a planetary mixer at a mass ratio of aluminum powder: polyethylene glycol = 1:1.93, and vacuum stirring for 5 hours to obtain the aluminum powder slurry) on the front and back sides of the central coating area of ​​the first aluminum foil obtained in step 1, and then drying, keeping the blank areas on both sides of the first aluminum foil blank, the coating area width is 170 mm, and the blank area widths on both sides are 15 mm, controlling the aluminum powder slurry to overlap the coating areas on the front and back sides of the first aluminum foil, and obtaining a laminated foil rough product with a thickness of 150 μm after segmented high-temperature sintering, and forming the coating area of ​​the laminated foil rough product at 700 V to obtain a laminated foil;

[0108] 3) Die-cut the laminated foil obtained in step 2 into an anode foil with a rectangular sheet structure, wherein the lower rectangular area of ​​the anode foil has an aluminum powder coating layer on both sides, and the upper anode tab has no coating layer. Use the same mold to die-cut the second aluminum foil obtained in step 1 into a cathode foil with a rectangular sheet structure;

[0109] 4) Processing the 27 anode foils and 28 cathode foils obtained in step 3 together with 30 μm thick electrolytic paper into a 055×59×88 mm laminated core package using a laminating machine;

[0110] 5) The laminated core package obtained in step 4 is sequentially subjected to the steps of tab cutting and shaping, ultrasonic spot welding, aluminum-plastic film forming, core package top and side sealing, vacuum drying, liquid injection, primary sealing, aging, puncturing the soft package to separate gas and excess electrolyte, and sealing again to obtain a 06×60×90 mm soft package liquid aluminum electrolytic capacitor product.

[0111] Embodiment 3:

[0112] 1) Process and customize two rolls of etched aluminum foil with a width of 200 mm, the thickness of the first aluminum foil is 30 microns, and the thickness of the second aluminum foil is 20 microns;

[0113] 2) using a transfer coater to sequentially coat aluminum powder slurry (selecting aluminum powder with an average particle size of 3.5 μm and adding it to a planetary mixer at a mass ratio of aluminum powder: polyethylene glycol = 1:1.93, and vacuum stirring for 5 hours to obtain the aluminum powder slurry) on the front and back sides of the central coating area of ​​the first aluminum foil obtained in step 1, and then drying, keeping the blank areas on both sides of the first aluminum foil blank, the width of the coating area is 170 mm, and the width of the blank areas on both sides is 15 mm, controlling the aluminum powder slurry to overlap the coating areas on the front and back sides of the first aluminum foil, and obtaining a laminated foil rough product with a thickness of 180 μm after segmented high-temperature sintering, and forming the coating area of ​​the laminated foil rough product at 800 V to obtain a laminated foil;

[0114] 3) Die-cut the laminated foil obtained in step 2 into an anode foil with a rectangular sheet structure, wherein the lower rectangular area of ​​the anode foil has an aluminum powder coating layer on both sides, and the upper anode tab has no coating layer. Use the same mold to die-cut the second aluminum foil obtained in step 1 into a cathode foil with a rectangular sheet structure;

[0115] 4) Processing the 24 anode foils and 25 cathode foils obtained in step 3 together with 30 μm thick electrolytic paper into a 055×59×88 mm laminated core package using a laminating machine;

[0116] 5) The laminated core package obtained in step 4 is sequentially subjected to the steps of tab cutting and shaping, ultrasonic spot welding, aluminum-plastic film forming, core package top and side sealing, vacuum drying, liquid injection, primary sealing, aging, puncturing the soft package to separate gas and excess electrolyte, and sealing again to obtain a 06×60×90 mm soft package liquid aluminum electrolytic capacitor product.

[0117] Embodiment 4:

[0118] 1) Process and customize two rolls of etched aluminum foil with a width of 200 mm, the thickness of the first aluminum foil is 30 microns, and the thickness of the second aluminum foil is 20 microns;

[0119] 2) using a transfer coater to sequentially coat aluminum powder slurry (selecting aluminum powder with an average particle size of 3.5 μm and adding it to a planetary mixer at a mass ratio of aluminum powder: polyethylene glycol = 1:1.93, and vacuum stirring for 5 hours to obtain the aluminum powder slurry) on the front and back sides of the central coating area of ​​the first aluminum foil obtained in step 1, and then drying, keeping the blank areas on both sides of the first aluminum foil blank, the width of the coating area is 170 mm, and the width of the blank areas on both sides is 15 mm, controlling the aluminum powder slurry to overlap the coating areas on the front and back sides of the first aluminum foil, and obtaining a laminated foil rough product with a thickness of 180 μm after segmented high-temperature sintering, and forming the coated area of ​​the laminated foil rough product at 900 V to obtain a laminated foil;

[0120] 3) Die-cut the laminated foil obtained in step 2 into an anode foil with a rectangular sheet structure, wherein the lower rectangular area of ​​the anode foil has an aluminum powder coating layer on both sides, and the upper anode tab has no coating layer. Use the same mold to die-cut the second aluminum foil obtained in step 1 into a cathode foil with a rectangular sheet structure;

[0121] 4) Processing the 24 anode foils and 25 cathode foils obtained in step 3 together with 30 μm thick electrolytic paper into a 055×59×88 mm laminated core package using a laminating machine;

[0122] 5) The laminated core package obtained in step 4 is sequentially subjected to the steps of tab cutting and shaping, ultrasonic spot welding, aluminum-plastic film forming, core package top and side sealing, vacuum drying, liquid injection, primary sealing, aging, puncturing the soft package to separate gas and excess electrolyte, and sealing again to obtain a 06×60×90 mm soft package liquid aluminum electrolytic capacitor product.

[0123] Comparative Example 1:

[0124] 1) A 130 μm thick corroded aluminum foil is formed at 700 V and cut into 84 mm width to obtain an anode foil;

[0125] 2) cutting the 20 μm thick corroded aluminum foil into 84 mm width to obtain a cathode foil;

[0126] 3) Winding the anode foil obtained in step 1 and the cathode foil obtained in step 2 together with 30 μm thick electrolytic paper into a 055×59×88 mm square structure core package, riveting the anode foil and the cathode foil with tabs during the winding process, and the top of the core package obtained after winding contains an anode foil tab and a cathode foil tab with a length of 10 mm and a width of 10 mm respectively;

[0127] 4) After ultrasonic spot welding the square structure core package obtained in step 3, the pole ear is wrapped in an aluminum-plastic film, and the core package is top-side sealed, vacuum dried, liquid injected, sealed once, aged, punctured to separate gas and excess electrolyte, and sealed again to obtain a 06×60×90 mm soft-package liquid aluminum electrolytic capacitor product.

[0128] Comparative Example 2:

[0129] 1) using a transfer coater to sequentially coat aluminum powder slurry (selecting aluminum powder with an average particle size of 3.5 microns and adding it into a planetary mixer at a mass ratio of aluminum powder: polyethylene glycol = 1:1.93, and vacuum stirring for 5 hours to obtain the aluminum powder slurry) on the front and back sides of a 30-micron-thick corroded aluminum foil, and then drying, and after staged high-temperature sintering, a laminated foil crude product with a thickness of 130 microns is obtained, and after 700 V chemical formation, a laminated foil is obtained;

[0130] 2) cutting the laminated foil obtained in step 1 into pieces with a width of 170 mm to obtain anode foil;

[0131] 3) cutting the 20 μm thick corroded aluminum foil into 170 mm width to obtain cathode foil;

[0132] 4) Winding the anode foil obtained in step 2 and the cathode foil obtained in step 3 together with 30 μm thick electrolytic paper into a 055×59×88 mm square structure core package, riveting the anode foil and the cathode foil with tabs during the winding process, and the top of the core package obtained after winding contains an anode foil tab and a cathode foil tab with a length of 10 mm and a width of 10 mm respectively;

[0133] 5) After ultrasonic spot welding, the square structure core package obtained in step 4 is wrapped in an aluminum-plastic film, and then the core package is top-side sealed, vacuum dried, liquid injected, sealed once, aged, the soft package is punctured to separate gas and excess electrolyte, and sealed again to obtain a 06×60×90 mm soft-package liquid aluminum electrolytic capacitor product.

[0134] Comparative Example 3:

[0135] 1) Process and customize two rolls of etched aluminum foil with a width of 200 mm, the thickness of the first aluminum foil is 130 microns, and the thickness of the second aluminum foil is 20 microns;

[0136] 2) forming the first aluminum foil obtained in step 1 at 700 V, controlling the width of the forming zone to be 170 mm in the center of the aluminum foil, and the width of the blank space on both sides to be 15 mm, to obtain a formed foil;

[0137] 3) Die-cut the formed foil obtained in step 2 into an anode foil with a rectangular sheet structure, wherein both sides of the lower rectangular area of ​​the anode foil are formed areas, and the upper anode tab is not formed. Use the same mold to die-cut the second aluminum foil obtained in step 1) into a cathode foil with a rectangular sheet structure;

[0138] 4) Processing the 30 anode foils and 31 cathode foils obtained in step 3 together with 30 μm thick electrolytic paper into a 055×59×88 mm laminated core package using a laminating machine;

[0139] 5) The laminated core package obtained in step 4 is sequentially subjected to the steps of tab cutting and shaping, ultrasonic spot welding, aluminum-plastic film forming, core package top and side sealing, vacuum drying, liquid injection, primary sealing, aging, puncturing the soft package to separate gas and excess electrolyte, and sealing again to obtain a 06×60×90 mm soft package liquid aluminum electrolytic capacitor product.

[0140] The test results are shown in the following table:

[0141]

[0142]

[0143] It can be seen from the test results in Table 1 that the soft-pack liquid aluminum electrolytic capacitor according to the embodiment of the present invention has high capacity, low internal resistance and low loss. Comparative Example 1 uses anode foil prepared by a traditional chemical formation process and assembles a soft-pack liquid aluminum electrolytic capacitor by a winding process. Compared with the performance of the laminated liquid process aluminum electrolytic capacitor assembled by the laminated foil of the present invention, the product capacity is more than 20% lower and the internal resistance is more than 120% higher. Comparative Example 2 uses laminated foil and assembles a soft-pack liquid aluminum electrolytic capacitor by a winding process. Since there is only one pair of tabs, the product internal resistance is relatively high. Comparative Example 3 uses anode foil prepared by a traditional chemical formation process and assembles a soft-pack liquid aluminum electrolytic capacitor by a lamination process. Due to the low product capacity, the internal resistance is relatively large.

[0144] The lower capacity of Example 3 and Example 4 is due to the high formation voltage of the laminated foil used and the high rated voltage of the capacitor. Whether it is aluminum foil or laminated foil, the higher the formation voltage, the lower the capacity; the formation process is actually anodization, in which the aluminum on the surface of the aluminum foil or laminated foil will react with the formation liquid under pressure to form an aluminum oxide film. The higher the formation voltage, the thicker the aluminum oxide film, which reduces the specific surface area of ​​the aluminum foil or laminated foil, so the specific volume is reduced.

[0145] The aluminum electrolytic capacitor may be a soft-pack liquid aluminum electrolytic capacitor.

[0146] Other structures and operations of the method for manufacturing the aluminum electrolytic capacitor according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0147] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0148] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for manufacturing an anode foil, characterized in that: The following steps are involved: Providing a first aluminum foil, wherein the first aluminum foil is divided into a coating area and two blank areas in a width direction, and the coating area is located between the two blank areas in the width direction of the first aluminum foil; Continuously coating aluminum powder slurry on two opposite surfaces of the coating area of ​​the first aluminum foil along the length direction of the first aluminum foil, and performing drying and sintering; Performing chemical forming on the coating area to obtain a laminated foil; The laminated foil is cut into a plurality of anode foils, each of which includes an anode foil main body formed by the coating region and an anode tab formed by the blank region.

2. The method for manufacturing an anode foil according to claim 1, characterized in that: The coating area is formed at a forming voltage of 600-1200V.

3. The method for manufacturing an anode foil according to claim 1, characterized in that: The first aluminum foil is a plain foil or a corroded foil, the width of the first aluminum foil is 150-250 mm, the width of the coated area is 120-220 mm, the width of the blank area is 10-20 mm, the thickness of the first aluminum foil is 20-60 μm, and the thickness of the laminated foil is 100-200 μm.

4. The method for manufacturing an anode foil according to claim 1, characterized in that: The aluminum powder slurry includes aluminum powder and a solvent, wherein the solvent is one or more of ethanol, pinene alcohol, ethylene glycol, polyethylene glycol, and diethylene glycol butyl ether, the average particle size of the aluminum powder is 1-10 microns, and the mass ratio of the aluminum powder to the solvent is 1:1.5-1:2.

5.

5. A method for manufacturing an aluminum electrolytic capacitor, characterized in that: The following steps are involved: Providing a first aluminum foil and a second aluminum foil, wherein the first aluminum foil is divided into a coating area and two blank areas in a width direction, and the coating area is located between the two blank areas in the width direction of the first aluminum foil; Continuously coating aluminum powder slurry on two opposite surfaces of the coating area of ​​the first aluminum foil along the length direction of the first aluminum foil, and performing drying and sintering; Performing chemical forming on the coating area to obtain a laminated foil; Cutting the laminated foil into a plurality of anode foils, wherein the anode foil comprises an anode foil main body formed by the coating area and an anode tab formed by the blank area, and cutting the second aluminum foil into a plurality of cathode foils, wherein the cathode foil comprises a cathode foil main body and a cathode tab; Alternately stacking a plurality of the anode foils and a plurality of the cathode foils with electrolytic paper sandwiched between each adjacent anode foil and cathode foil, and processing them into a core package; The core package is coated with an aluminum-plastic film to form a soft package, and an electrolyte is injected into the soft package and the soft package is sealed.

6. The method for manufacturing an aluminum electrolytic capacitor according to claim 5, wherein: After injecting electrolyte into the soft package and sealing it, the following steps are also included: Performing an aging treatment on the soft package; Puncture the soft bag in a vacuum environment to discharge gas and excess electrolyte; The soft bag is sealed again.

7. The method for manufacturing an aluminum electrolytic capacitor according to claim 5, wherein: The number of the cathode foils in the core package is one more than the number of the anode foils.

8. The method for manufacturing an aluminum electrolytic capacitor according to claim 5, wherein: The coating area is formed at a forming voltage of 600-1200V.

9. The method for manufacturing an aluminum electrolytic capacitor according to claim 5, wherein: The first aluminum foil is a plain foil or an etched foil and has a width of 150-250 mm, the width of the coated area is 120-220 mm, the width of the blank area is 10-20 mm, the thickness of the first aluminum foil is 20-60 μm, the thickness of the laminated foil is 100-200 μm, the second aluminum foil is a plain foil or an etched foil and has a width of 150-250 mm, and the thickness of the second aluminum foil is 10-30 μm.

10. The method for manufacturing an aluminum electrolytic capacitor according to claim 5, wherein: The aluminum powder slurry includes aluminum powder and a solvent, wherein the solvent is one or more of ethanol, pinene alcohol, ethylene glycol, polyethylene glycol, and diethylene glycol butyl ether, the average particle size of the aluminum powder is 1-10 microns, and the mass ratio of the aluminum powder to the solvent is 1:1.5-1:2.5.

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