Manufacturing method of aluminum electrolytic capacitor core

Abstract

The invention discloses a manufacturing method of an aluminum electrolytic capacitor core. The manufacturing method comprises the following steps: S1, placing an electrode foil and a guide pin on a mold; s2, the die comprises a riveting position, and the guide pin is perforated on the riveting position and riveted to be connected with the electrode foil; s3, the riveted electrode foil and the guide pin are placed in an arc-shaped groove in a mold; s4, an arc-shaped punch matched with the arc-shaped groove in shape is used for punching the guide pin and the electrode foil, and arc-shaped butt joint parts are formed in the contact areas of the two sides of the riveting position of the guide pin and the electrode foil; and S5, winding the electrode foil riveted with the guide pin and electrolytic paper to form a core. According to the manufacturing method of the aluminum electrolytic capacitor core provided by the invention, sudden stress change of right-angle riveting can be avoided, and meanwhile, the aluminum foil can be guided to extend and deform, so that a smooth turned flower structure is formed, and a needle flower sharp edge is eliminated.

Description

A method for manufacturing an aluminum electrolytic capacitor core Technical Field

[0001] This invention relates to the field of capacitor technology, and in particular to a method for manufacturing an aluminum electrolytic capacitor core. Background Technology

[0002] For example, publication number "CN120356788A" discloses "a solid capacitor and its preparation method", which includes the following steps: (1) Core winding: electrolytic paper is inserted between the anode foil and the cathode foil and wound into a core; (2) Repair step: the core is immersed in the formation liquid for repair treatment; (3) Drying step: the core of step (2) is dried; (4) Impregnation step: the core of step (3) is immersed in the first impregnation liquid for impregnation treatment; dried; immersed in the second impregnation liquid for impregnation treatment, dried; (5) Polymerization step: the core of step (4) is immersed in the oxidation liquid for polymerization; (6) Assembly waisting and aging treatment. However, in practical applications, this type of operation method may cause cracks near the rivet when the guide pin is on the electrode foil surface. After the rivet is wound into a core with a certain curvature, it will aggravate the cracks and burrs at the electrode foil rivet. These burrs may puncture the electrolytic paper. When the capacitor is subjected to instantaneous high voltage and high current impact or high frequency charging and discharging, it may short circuit, spark or even explode. At the same time, the sharp edge of the guide pin may also cause the electrode foil to crack. Summary of the Invention

[0003] In view of the problem mentioned in the background art that the existing technology may cause aluminum foil to crack and puncture the electrolytic paper during the winding process, the present invention provides a method for manufacturing aluminum electrolytic capacitor core, which can avoid stress abrupt changes in right-angle riveting, and at the same time guide the aluminum foil to stretch and deform to form a smooth embossed structure and eliminate the sharp edges of "needlework".

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A method for manufacturing an aluminum electrolytic capacitor core includes the following steps: S1, placing an electrode foil and a guide pin on a mold; S2, the mold includes a riveting position, and the guide pin is drilled and riveted to connect with the electrode foil at the riveting position; S3, placing the riveted electrode foil and guide pin in an arc-shaped groove on the mold; S4, using an arc-shaped punch adapted to the shape of the arc-shaped groove to punch the guide pin and the electrode foil, forming an arc-shaped mating part on both sides of the guide pin's riveting point in contact with the electrode foil; S5, winding the riveted guide pin electrode foil with electrolytic paper to form a core.

[0006] In existing technology, because the guide pins need to be riveted to the electrode foil using a riveting process, perforations occur in the complete electrode foil, thereby compromising its structural strength. The core of an aluminum electrolytic capacitor consists of a positive electrode guide pin riveted to an anode foil, a negative electrode guide pin riveted to a cathode foil, and an interlayer of electrolytic paper. These three materials are overlapped and wound on a riveting machine. Both the anode and cathode foils are electrode foils. Since the anode foil is thicker than the cathode foil, typically 100–200 μm, the bending strength of the anode foil is affected by factors such as the bending strength of the positive electrode guide pin. On the anode foil surface, cracks may sometimes appear near the rivet pins. After the rivet is wound into a core with a certain curvature, the cracks and burrs at the rivet of the anode foil will be aggravated. These burrs may puncture the electrolytic paper. When the capacitor is subjected to instantaneous high voltage and high current impact or high frequency charging and discharging, short circuits, arcing or even explosion may occur. Furthermore, during the winding process, when the sharp edges on both sides of the guide pin contact the electrode foil, stress concentration will occur in the area where the electrode foil contacts the sharp edges. This will prevent the electrode foil from extending smoothly and will create areas of plastic deformation, which are prone to forming expanding cracks.

[0007] To address the aforementioned technical problems, this application, after the guide pin and electrode foil are riveted, places them in an arc-shaped groove and stamps them with an arc-shaped punch. This allows the contact points between the electrode foil and the guide pin to be simultaneously pressurized to form an arc-shaped joint. Under the stamping of the arc-shaped punch, the contact between the guide pin and the electrode foil is tighter, and an arc-shaped structure is formed on both sides of the riveting point. The curved surface allows the riveting force to be released in a gradient along the arc direction, thereby avoiding the stress abrupt change of right-angle riveting, reducing the risk of further crack propagation, and thus ensuring structural strength. Furthermore, the arc surface formed by stamping can guide the electrode foil (aluminum foil) to extend and deform, thereby forming a smooth embossed structure and eliminating the sharp edge structure of "needlework". Since the arc-shaped rivet itself has curvature, it can match the cylindrical curvature of the subsequent core winding, thereby improving the bending fatigue strength. During winding, the arc-shaped area can be within the elastic deformation range (rather than plastic deformation), avoiding crack propagation and reducing bending stress.

[0008] Preferably, the riveting position includes a pre-punched hole position and a riveting position, with the riveting position located on the side of the pre-punched hole position near the arc groove. By setting the pre-punched hole position and the riveting position on the riveting position, with the riveting position located on the side of the pre-punched hole position near the arc groove, the guide pin and the electrode foil sequentially pass through the pre-punched hole position, the riveting position, and the arc groove on the mold, thereby achieving the effects of pre-punching, riveting, and arc flattening, thus improving production efficiency.

[0009] Preferably, the curvature of the arc-shaped mating portion formed in step S4 is adapted to the curvature of the core winding in step S5. Matching the curvature of the arc-shaped mating portion to the curvature of the core winding ensures that the two sides of the guide pin can guide the winding of the electrode foil during the core winding process, guaranteeing smooth bending of the electrode foil and resulting in smoother stress transmission.

[0010] Preferably, the arc-shaped groove on the mold used in step S3 includes two arc-shaped recesses, with an arc-shaped protrusion between the two recesses; two arc-shaped punches are used in step S4, each aligned with one of the two arc-shaped recesses, with a recessed area between the two punches that mates with the arc-shaped protrusion. The arc-shaped groove includes two arc-shaped grooves and one arc-shaped protrusion, with the protrusion positioned between the two grooves; the stamping unit positioned above the arc-shaped groove has two arc-shaped punches, with a recessed area between them. The two arc-shaped punches correspond to the two arc-shaped grooves, thereby ensuring that the guide pin and electrode foil can be uniformly squeezed during the stamping process, ensuring the uniformity of the stamping force, and ensuring that the guide pin and electrode foil can be quickly deformed and bent, thus improving production stability and efficiency.

[0011] Preferably, the electrode foil includes an anode foil and a cathode foil, with corresponding guide pins connected to both. In step S5, an additional layer of electrolytic paper is added between the anode foil and the cathode foil. The electrode foil is divided into an anode foil and a cathode foil. Burrs may exist at the rivet points between the positive electrode guide pin and the anode foil. These burrs originate from the sharp edges of the aluminum tongue and reinforcing ribs of the positive electrode guide pin, forming a four-petal shape after the guide pin's aluminum tongue pierces the anode foil. During winding, these burrs may puncture the electrolytic paper in the middle layer between the anode foil and the cathode foil. When the capacitor is subjected to instantaneous high voltage and current surges or high-frequency charging and discharging, short circuits, arcing, or even explosions may occur. Therefore, this application adds one or more layers of electrolytic paper to the area where the guide pin contacts the electrolytic paper on the anode foil, thereby increasing the number and thickness of the electrolytic paper in the contact area with the guide pin. This reduces the probability of burrs directly piercing the electrolytic paper and ensures the stability of the core during operation.

[0012] Preferably, in step S5, when the guide pin on the anode foil is about to come into contact with the cathode foil and the electrolytic paper, additional electrolytic paper is placed at the point where the guide pin will come into contact and is wound simultaneously. Additional electrolytic paper is added in the area where the guide pin contacts the electrolytic paper. This additional electrolytic paper is placed between the guide pin and the electrolytic paper when the winding reaches the guide pin, ensuring that the additional electrolytic paper is stably wound between the two, thus guaranteeing the stability of the additional electrolytic paper placement.

[0013] Preferably, the additional electrolytic paper only covers the guide pin area on the anode foil. The additional electrolytic paper is not the same length as the original electrolytic paper, but only covers the guide pin area on the anode foil. This reduces the probability of burrs penetrating the electrolytic paper, avoids increasing the overall size of the core, and reduces the increase in material costs.

[0014] Preferably, during unwinding, the electrolytic paper is stretched and folded additionally at the unwinding point. During winding, the guide pins on the anode foil are in contact with the additionally folded area of ​​the electrolytic paper. The additional electrolytic paper in this application is not a new electrolytic paper independent of the original electrolytic paper, but rather the original electrolytic paper is stretched and folded at the unwinding point (i.e., the area where the guide pins on the anode foil need to contact the electrolytic paper). This results in multiple layers of stacked electrolytic paper at this location. Since the additional electrolytic paper is folded from the original electrolytic paper, the folded electrolytic paper is integrally connected to the original electrolytic paper, ensuring the stability of the extra stretched and folded electrolytic paper, reducing the risk of the electrolytic paper coming off, and maintaining the integrity of the electrolytic paper. This improves the quality of core forming and avoids the need for additional cutting and soaking steps, ensuring production quality.

[0015] Preferably, after the core winding is completed in step S5, an electronic tape is wrapped around the outermost ring of the core. The width of the electronic tape is smaller than the width of the electrolytic paper and larger than the width of the electrode foil. The outermost ring of the core of an aluminum electrolytic capacitor is typically wrapped with electronic tape at least 1.5 turns around the center of the core cylinder. The width of the electronic tape is generally smaller than the width of the anode foil of this core. With this winding, the upper and lower parts of the outermost edge of the core may have the electrolytic paper and negative electrode foil warped or exposed, causing the electrode foil ends to be damaged and come into contact, leading to a short circuit and arcing. When such a core is impregnated and fed onto the vibratory feeder of the assembly machine, the vibration will wear away the electrolytic paper at the outermost edge of the core, causing the positive and negative electrode foils to come into contact and cause a short circuit and arcing. Therefore, to address the above issues, in this application, after the core winding is completed, an electronic tape is wrapped around the outermost layer, and the width of the electronic tape is set to be larger than the width of the electrode foil and smaller than the width of the electrolytic paper, thereby avoiding damage to the electrode foil and improving the stability of the structure.

[0016] Preferably, the width of the electronic tape is 1 mm less than the width of the electrolytic paper, and the electronic tape is wrapped around the outer layer 1.5 times.

[0017] The beneficial effects of the present invention are as follows: (1) It can reduce the probability of cracking and burrs at the riveting point after the anode foil is wound into a core after riveting; (2) The length of the electrolytic paper fold at the core starting point is designed to cover the positive electrode guide pin and the anode foil rivet part, adding a layer of electrolytic paper to the original process, thereby improving the breakdown resistance of aluminum electrolytic capacitors; (3) The electronic tape can completely cover the cut ends of the anode foil, negative electrode foil and electrolytic paper at the end of the core, which can avoid short circuit breakdown caused by factors such as the last cut end lifting, exposure, and damage. Attached Figure Description

[0018] Figure 1 is a top view of the mold in this invention.

[0019] Figure 2 is an isometric view of the mold in this invention.

[0020] Figure 3 is a schematic diagram of the unfolded core structure in this invention.

[0021] Figure 4 is a top view of the connection between the electrode foil and the guide needle in this invention.

[0022] Figure 5 is a structural schematic diagram of Embodiment 2.

[0023] Figure 6 is a structural schematic diagram of Example 3.

[0024] In the figure: 1 Electrode foil, 11 Anode foil, 12 Cathode foil, 2 Guide pin, 3 Riveting position, 31 Pre-punched hole position, 32 Punching and riveting position, 4 Arc groove, 41 Arc recess, 42 Arc protrusion, 5 Arc punch, 6 Arc mating part, 7 Electrolytic paper, 8 Electronic tape, 9 Mold. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1: As shown in Figures 1, 2, 3, and 4, a method for manufacturing an aluminum electrolytic capacitor core includes the following steps: S1, placing electrode foil 1 and guide pin 2 on a mold 9; S2, the mold 9 includes a riveting position 3, the guide pin 2 is drilled in the riveting position 3 and riveted to connect with the electrode foil 1; S3, placing the riveted electrode foil 1 and guide pin 2 in an arc-shaped groove 4 on the mold 9; S4, an arc-shaped punch 5 adapted to the shape of the arc-shaped groove 4 punches the guide pin 2 and electrode foil 1, forming an arc-shaped mating part 6 on both sides of the riveting point of the guide pin 2 in contact with the electrode foil 1; S5, winding the electrode foil 1 with the riveted guide pin 2 and electrolytic paper 7 to form a core.

[0027] In the existing technology, because the guide pin 2 needs to be riveted to the electrode foil 1 through a riveting process, the complete electrode foil 1 will have perforations, thereby destroying the structural strength of the electrode foil 1. The core of the aluminum electrolytic capacitor is formed by riveting the positive electrode guide pin 2 to the anode foil 11 and the negative electrode guide pin 2 to the cathode foil 12, with electrolytic paper 7 in the middle. The three materials are overlapped and wound on a riveting and winding machine. The anode foil 11 and the cathode foil 12 are both electrode foils 1. Since the anode foil 11 is thicker than the cathode foil 12, it is generally 100 to 200 μm thicker. Due to the influence of the bending strength factor of the anode foil 11, when the positive electrode guide pin 2 is riveted to the cathode foil 12, the core of the aluminum electrolytic capacitor is formed by riveting the positive electrode guide pin 2 to the anode foil 11 and the cathode foil 12. When the electrode guide pin 2 is riveted on the surface of the anode foil 11, it may cause foil cracks near the rivet pin flower. After the rivet is wound into a core with a certain curvature, it will aggravate the cracks and burrs at the rivet of the anode foil 11. These burrs may puncture the electrolytic paper 7. When the capacitor is subjected to instantaneous high voltage and high current impact or high frequency charging and discharging, it may short circuit, spark or even explode. In addition, during the winding process, when the sharp edges on both sides of the guide pin 2 contact the electrode foil 1, stress concentration will occur in the area where the electrode foil 1 contacts the sharp edge, making the extension of the electrode foil 1 not smooth, and creating areas of plastic deformation, which are prone to forming expanding cracks.

[0028] To address the aforementioned technical problems, this application, after the guide pin 2 and electrode foil 1 are riveted, uses an arc-shaped punch 5 to press the electrode foil 1 and guide pin 2 together in an arc-shaped groove 4. This allows the contact points between the electrode foil 1 and guide pin 2 to be simultaneously pressurized to form an arc-shaped mating part 6. Under the pressing of the arc-shaped punch 5, the contact between the guide pin 2 and electrode foil 1 is tighter, and an arc-shaped structure is formed on both sides of the riveting point. The curved surface allows the riveting force to be released in a gradient along the arc direction, thereby avoiding the stress abrupt change of right-angle riveting, reducing the risk of further expansion of cracks, and thus ensuring structural strength. Furthermore, the arc surface formed by the pressing can guide the electrode foil 1 (aluminum foil) to extend and deform, thereby forming a smooth embossed structure and eliminating the sharp edge structure of "needlework". Furthermore, since the arc-shaped rivet formed by stamping itself has curvature, it can match the cylindrical curvature of the subsequent core winding, thereby improving the bending fatigue strength; and during winding, the arc-shaped area can be in the range of elastic deformation (rather than plastic deformation), avoiding crack propagation and reducing bending stress.

[0029] As shown in Figure 2, the riveting position 3 includes a pre-punching position 31 and a riveting position 32, with the riveting position 32 positioned on the side of the pre-punching position 31 near the arc groove 4. By setting the pre-punching position 31 and the riveting position 32 on the riveting position 3, with the riveting position 32 positioned on the side of the pre-punching position 31 near the arc groove 4, the guide pin 2 and the electrode foil 1 sequentially pass through the pre-punching position 31, the riveting position 32, and the arc groove 4 on the mold 9, thereby achieving the effects of pre-punching, riveting, and arc flattening, and improving production efficiency.

[0030] The curvature of the arc-shaped mating portion 6 formed in step S4 is adapted to the curvature of the core winding in step S5. By matching the curvature of the arc-shaped mating portion 6 with the curvature of the core winding, it is possible to ensure that the two sides of the guide pin 2 can guide the winding of the electrode foil 1 during the core winding process, ensuring the smooth bending of the electrode foil 1 and making stress transmission smoother.

[0031] As shown in Figure 2, the arc-shaped groove 4 on the mold 9 used in step S3 includes two arc-shaped recesses 41, with an arc-shaped protrusion 42 between the two recesses 41. Two arc-shaped punches 5 are used in step S4, each aligned with one of the two arc-shaped recesses 41, with a recessed area between the two punches 5 that mates with the arc-shaped protrusion 42. The arc-shaped groove 4 includes two arc-shaped recesses and one arc-shaped protrusion 42, with the protrusion 42 positioned between the two recesses. The stamping unit positioned above the arc-shaped groove 4 has two arc-shaped punches 5, with a recessed area between them. The two punches 5 correspond to the two arc-shaped recesses, ensuring uniform compression of the guide pin 2 and electrode foil 1 during the stamping process, guaranteeing uniform stamping pressure, and ensuring rapid deformation and bending of the guide pin 2 and electrode foil 1, thereby improving production stability and efficiency.

[0032] Example 2: As shown in Figure 5, a method for manufacturing an aluminum electrolytic capacitor core includes the following steps: S1, placing the electrode foil 1 and the guide pin 2 on a mold 9; S2, the mold 9 includes a riveting position 3, the guide pin 2 is drilled in the riveting position 3 and riveted to connect with the electrode foil 1; S3, placing the riveted electrode foil 1 and the guide pin 2 in an arc-shaped groove 4 on the mold 9; S4, an arc-shaped punch 5, adapted to the shape of the arc-shaped groove 4, punches the guide pin 2 and the electrode foil 1, forming an arc-shaped mating part 6 on both sides of the riveting point of the guide pin 2 in contact with the electrode foil 1; S5, rolling the electrode foil 1 with the riveted guide pin 2 and the electrolytic paper 7 together. The electrode foil 1 is wound to form a core; the electrode foil 1 includes an anode foil 11 and a cathode foil 12, and corresponding guide pins 2 are connected to both the anode foil 11 and the cathode foil 12. An additional layer of electrolytic paper 7 is added between the anode foil 11 and the cathode foil 12. When the guide pins 2 on the anode foil 11 are about to be attached to the cathode foil 12 and the electrolytic paper 7, the additional electrolytic paper 7 is placed at the attachment point of the guide pins 2 and wound synchronously. The additional electrolytic paper 7 only covers the area of ​​the guide pins 2 on the anode foil 11. When starting to wind, the electrolytic paper 7 is stretched and folded at the starting point. During the winding process, the guide pins 2 on the anode foil 11 are attached to the additional folded area of ​​the electrolytic paper 7.

[0033] In this application, after the guide pin 2 and the electrode foil 1 are riveted, they are stamped in the arc groove 4 using an arc punch 5. This allows the contact points between the electrode foil 1 and the guide pin 2 to be simultaneously pressurized to form an arc-shaped mating part 6. Under the stamping of the arc punch 5, the contact between the guide pin 2 and the electrode foil 1 is tighter, and an arc-shaped structure is formed on both sides of the riveting point between the guide pin 2 and the electrode foil 1. The curved surface allows the riveting force to be released in a gradient along the arc direction, thereby avoiding the stress abrupt change of right-angle riveting, reducing the risk of further expansion of cracks, and thus ensuring structural strength. Furthermore, the arc surface formed by stamping can guide the electrode foil 1 (aluminum foil) to extend and deform, thereby forming a smooth embossed structure and eliminating the sharp edge structure of "needle flower". Furthermore, since the arc-shaped rivet formed by stamping itself has curvature, it can match the cylindrical curvature of the subsequent core winding, thereby improving the bending fatigue strength; and during winding, the arc-shaped area can be in the range of elastic deformation (rather than plastic deformation), avoiding crack propagation and reducing bending stress.

[0034] The riveting position 3 includes a pre-punching position 31 and a riveting position 32, with the riveting position 32 located on the side of the pre-punching position 31 near the arc groove 4. By setting the pre-punching position 31 and the riveting position 32 on the riveting position 3, and placing the riveting position 32 on the side of the pre-punching position 31 near the arc groove 4, the guide pin 2 and the electrode foil 1 sequentially pass through the pre-punching position 31, the riveting position 32, and the arc groove 4 on the mold 9, thereby achieving the effects of pre-punching, riveting, and arc flattening, and improving production efficiency.

[0035] The curvature of the arc-shaped mating portion 6 formed in step S4 is adapted to the curvature of the core winding in step S5. By matching the curvature of the arc-shaped mating portion 6 with the curvature of the core winding, it is possible to ensure that the two sides of the guide pin 2 can guide the winding of the electrode foil 1 during the core winding process, ensuring the smooth bending of the electrode foil 1 and making stress transmission smoother.

[0036] The arc-shaped groove 4 on the mold 9 used in step S3 includes two arc-shaped recesses 41, with an arc-shaped protrusion 42 between the two recesses 41. Two arc-shaped punches 5 are used in step S4, each aligned with one of the two arc-shaped recesses 41, with a recessed area between the two punches 5 that mates with the arc-shaped protrusion 42. The arc-shaped groove 4 includes two arc-shaped recesses and one arc-shaped protrusion 42, with the protrusion 42 positioned between the two recesses. The stamping unit positioned above the arc-shaped groove 4 has two arc-shaped punches 5, with a recessed area between them. The two punches 5 correspond to the two arc-shaped recesses, ensuring uniform compression of the guide pin 2 and electrode foil 1 during the stamping process, guaranteeing uniform stamping pressure, and ensuring rapid deformation and bending of the guide pin 2 and electrode foil 1, thereby improving production stability and efficiency.

[0037] The electrode foil 1 is divided into an anode foil 11 and a cathode foil 12. There may be burrs at the rivet point between the positive electrode guide pin 2 and the anode foil 11. These burrs come from the sharp edges of the aluminum tongue and reinforcing ribs of the positive electrode guide pin 2. After the aluminum tongue of the guide pin 2 is riveted, it bites into the anode foil 11 like a four-petaled petal. During the winding process, the burrs in this part may puncture the electrolytic paper 7 in the middle layer between the anode foil 11 and the cathode foil 12. When the capacitor is subjected to instantaneous high voltage and high current impact or high frequency charging and discharging, short circuits, arcing or even explosion may occur. Therefore, this application adds one or more layers of electrolytic paper 7 to the area where the guide pin 2 contacts the electrolytic paper 7 on the anode foil 11, thereby increasing the number and thickness of the electrolytic paper 7 in the contact area with the guide pin 2, thereby reducing the probability of burrs directly puncturing the electrolytic paper 7 and ensuring the stability of the core during operation.

[0038] An additional electrolytic paper 7 is added in the area where the guide needle 2 contacts the electrolytic paper 7. When the additional electrolytic paper 7 is about to contact the guide needle 2, it is placed between the guide needle 2 and the electrolytic paper 7, so as to ensure that the additional electrolytic paper 7 is stably wound between the two when it is wound to the guide needle 2, and to ensure the placement stability of the additional electrolytic paper 7.

[0039] The additional electrolytic paper 7 is not the same length as the original electrolytic paper 7, but only covers the area of ​​the guide needle 2 on the anode foil 11. This reduces the probability of burrs penetrating the electrolytic paper 7, avoids increasing the overall size of the core, and reduces the increase in material costs.

[0040] The additional electrolytic paper 7 in this application is not a new electrolytic paper 7 independent of the original electrolytic paper 7. Instead, the original electrolytic paper 7 is stretched and folded at the starting position (that is, the area where the guide pin 2 on the anode foil 11 needs to contact the electrolytic paper 7), so that multiple layers of electrolytic paper 7 are stacked at this position. Since the additional electrolytic paper 7 is folded from the original electrolytic paper 7, the folded electrolytic paper 7 is integrally connected with the original electrolytic paper 7, which ensures the stability of the extra stretched and folded electrolytic paper 7, reduces the risk of the electrolytic paper 7 coming off, and ensures the integrity of the electrolytic paper 7, improves the quality of core forming, and avoids the need for additional cutting of new electrolytic paper 7 and soaking steps, thus ensuring production quality.

[0041] Example 3: As shown in Figure 6, a method for manufacturing an aluminum electrolytic capacitor core includes the following steps: S1, placing electrode foil 1 and guide pin 2 on a mold 9; S2, the mold 9 includes a riveting position 3, the guide pin 2 is drilled in the riveting position 3 and riveted to connect with the electrode foil 1; S3, placing the riveted electrode foil 1 and guide pin 2 in an arc-shaped groove 4 on the mold 9; S4, an arc-shaped punch 5 adapted to the shape of the arc-shaped groove 4 punches the guide pin 2 and electrode foil 1, forming an arc-shaped mating part 6 on both sides of the riveting part of the guide pin 2 in contact with the electrode foil 1; S5, winding the riveted electrode foil 1 with electrolytic paper 7 to form a core. 1. The guide pin 2 is placed in the arc-shaped groove 4 on the mold 9; S4. The arc-shaped punch 5, which is adapted to the shape of the arc-shaped groove 4, punches the guide pin 2 and the electrode foil 1, forming an arc-shaped mating part 6 on both sides of the riveting part of the guide pin 2 and the contact area with the electrode foil 1; S5. The electrode foil 1 with the riveted guide pin 2 is wound with the electrolytic paper 7 to form a core; The electrode foil 1 includes an anode foil 11 and a cathode foil 12, and corresponding guide pins 2 are connected to both the anode foil 11 and the cathode foil 12. An additional layer of electrolytic paper 7 is added between the anode foil 11 and the cathode foil 12; when the guide pin 2 on the anode foil 11 is about to be attached to the cathode foil 12 and the electrolytic paper 7, the additional electrolytic paper 7 is placed at the attachment point of the guide pin 2 and wound synchronously; the additional electrolytic paper 7 only covers the area of ​​the guide pin 2 on the anode foil 11; when starting to roll, the electrolytic paper 7 is stretched and folded additionally at the starting point, and during the winding process, the guide pin 2 on the anode foil 11 is attached to the additional folded area of ​​the electrolytic paper 7.

[0042] S6. Wrap an electronic tape 8 around the outermost ring of the core. The width of the electronic tape 8 is smaller than the width of the electrolytic paper 7, but larger than the width of the electrode foil 1. The width of the electronic tape 8 is 1 mm less than the width of the electrolytic paper 7. The electronic tape 8 is wrapped around the outer layer 1.5 times.

[0043] In this application, after the guide pin 2 and the electrode foil 1 are riveted, they are stamped in the arc groove 4 using an arc punch 5. This allows the contact points between the electrode foil 1 and the guide pin 2 to be simultaneously pressurized to form an arc-shaped mating part 6. Under the stamping of the arc punch 5, the contact between the guide pin 2 and the electrode foil 1 is tighter, and an arc-shaped structure is formed on both sides of the riveting point between the guide pin 2 and the electrode foil 1. The curved surface allows the riveting force to be released in a gradient along the arc direction, thereby avoiding the stress abrupt change of right-angle riveting, reducing the risk of further expansion of cracks, and thus ensuring structural strength. Furthermore, the arc surface formed by stamping can guide the electrode foil 1 (aluminum foil) to extend and deform, thereby forming a smooth embossed structure and eliminating the sharp edge structure of "needle flower". Furthermore, since the arc-shaped rivet formed by stamping itself has curvature, it can match the cylindrical curvature of the subsequent core winding, thereby improving the bending fatigue strength; and during winding, the arc-shaped area can be in the range of elastic deformation (rather than plastic deformation), avoiding crack propagation and reducing bending stress.

[0044] The riveting position 3 includes a pre-punching position 31 and a riveting position 32, with the riveting position 32 located on the side of the pre-punching position 31 near the arc groove 4. By setting the pre-punching position 31 and the riveting position 32 on the riveting position 3, and placing the riveting position 32 on the side of the pre-punching position 31 near the arc groove 4, the guide pin 2 and the electrode foil 1 sequentially pass through the pre-punching position 31, the riveting position 32, and the arc groove 4 on the mold 9, thereby achieving the effects of pre-punching, riveting, and arc flattening, and improving production efficiency.

[0045] The curvature of the arc-shaped mating portion 6 formed in step S4 is adapted to the curvature of the core winding in step S5. By matching the curvature of the arc-shaped mating portion 6 with the curvature of the core winding, it is possible to ensure that the two sides of the guide pin 2 can guide the winding of the electrode foil 1 during the core winding process, ensuring the smooth bending of the electrode foil 1 and making stress transmission smoother.

[0046] The arc-shaped groove 4 on the mold 9 used in step S3 includes two arc-shaped recesses 41, with an arc-shaped protrusion 42 between the two recesses 41. Two arc-shaped punches 5 are used in step S4, each aligned with one of the two arc-shaped recesses 41, with a recessed area between the two punches 5 that mates with the arc-shaped protrusion 42. The arc-shaped groove 4 includes two arc-shaped recesses and one arc-shaped protrusion 42, with the protrusion 42 positioned between the two recesses. The stamping unit positioned above the arc-shaped groove 4 has two arc-shaped punches 5, with a recessed area between them. The two punches 5 correspond to the two arc-shaped recesses, ensuring uniform compression of the guide pin 2 and electrode foil 1 during the stamping process, guaranteeing uniform stamping pressure, and ensuring rapid deformation and bending of the guide pin 2 and electrode foil 1, thereby improving production stability and efficiency.

[0047] The electrode foil 1 is divided into an anode foil 11 and a cathode foil 12. There may be burrs at the rivet point between the positive electrode guide pin 2 and the anode foil 11. These burrs come from the sharp edges of the aluminum tongue and reinforcing ribs of the positive electrode guide pin 2. After the aluminum tongue of the guide pin 2 is riveted, it bites into the anode foil 11 like a four-petaled petal. During the winding process, the burrs in this part may puncture the electrolytic paper 7 in the middle layer between the anode foil 11 and the cathode foil 12. When the capacitor is subjected to instantaneous high voltage and high current impact or high frequency charging and discharging, short circuits, arcing or even explosion may occur. Therefore, this application adds one or more layers of electrolytic paper 7 to the area where the guide pin 2 contacts the electrolytic paper 7 on the anode foil 11, thereby increasing the number and thickness of the electrolytic paper 7 in the contact area with the guide pin 2, thereby reducing the probability of burrs directly puncturing the electrolytic paper 7 and ensuring the stability of the core during operation.

[0048] An additional electrolytic paper 7 is added in the area where the guide needle 2 contacts the electrolytic paper 7. When the additional electrolytic paper 7 is about to contact the guide needle 2, it is placed between the guide needle 2 and the electrolytic paper 7, so as to ensure that the additional electrolytic paper 7 is stably wound between the two when it is wound to the guide needle 2, and to ensure the placement stability of the additional electrolytic paper 7.

[0049] The additional electrolytic paper 7 is not the same length as the original electrolytic paper 7, but only covers the area of ​​the guide needle 2 on the anode foil 11. This reduces the probability of burrs penetrating the electrolytic paper 7, avoids increasing the overall size of the core, and reduces the increase in material costs.

[0050] The additional electrolytic paper 7 in this application is not a new electrolytic paper 7 independent of the original electrolytic paper 7. Instead, the original electrolytic paper 7 is stretched and folded at the starting position (that is, the area where the guide pin 2 on the anode foil 11 needs to contact the electrolytic paper 7), so that multiple layers of electrolytic paper 7 are stacked at this position. Since the additional electrolytic paper 7 is folded from the original electrolytic paper 7, the folded electrolytic paper 7 is integrally connected with the original electrolytic paper 7, which ensures the stability of the extra stretched and folded electrolytic paper 7, reduces the risk of the electrolytic paper 7 coming off, and ensures the integrity of the electrolytic paper 7, improves the quality of core forming, and avoids the need for additional cutting of new electrolytic paper 7 and soaking steps, thus ensuring production quality.

[0051] In aluminum electrolytic capacitors, the outermost ring of the core is typically wrapped with electronic tape 8 at least 1.5 turns around the center of the core cylinder. The width of the electronic tape 8 is generally smaller than the width of the anode foil 11 pieces. This winding method can result in the electrolytic paper 7 and negative electrode foil being warped or exposed at the top and bottom of the core, causing damage to the electrode foil 1 and leading to contact and short circuits. Furthermore, when such a core is impregnated and fed onto the vibratory feeder of an assembly machine, the vibration can wear down the electrolytic paper 7 at the outermost end of the core, causing the positive and negative electrode foils to contact and trigger short circuits. Therefore, to address these issues, this application involves wrapping an outermost layer of electronic tape 8 after the core is wound. The width of the electronic tape 8 is greater than the width of the electrode foil 1 but less than the width of the electrolytic paper 7, thereby preventing damage to the electrode foil 1 and improving structural stability.

Claims

1. A method for manufacturing an aluminum electrolytic capacitor core, characterized in that, The process includes the following steps: S1, placing the electrode foil and guide pin on the mold; S2, the mold includes a riveting position, the guide pin is drilled in the riveting position and riveted to connect with the electrode foil; S3, placing the riveted electrode foil and guide pin in the arc groove on the mold. S4. An arc-shaped punch, used for adapting the shape of the arc groove, punches the guide pin and the electrode foil, forming an arc-shaped mating part on both sides of the guide pin riveting area in contact with the electrode foil; S5. The electrode foil riveted to the guide pin is wound with electrolytic paper to form a core.

2. The method for manufacturing an aluminum electrolytic capacitor core according to claim 1, characterized in that, The riveting position includes a pre-punched hole position and a riveting position, wherein the riveting position is located on the side of the pre-punched hole position near the arc groove.

3. The method for manufacturing an aluminum electrolytic capacitor core according to claim 1, characterized in that, The curvature of the arc-shaped mating part formed in step S4 is adapted to the curvature of the core winding in step S5.

4. The method for manufacturing an aluminum electrolytic capacitor core according to claim 1, characterized in that, The arc-shaped groove on the mold used in step S3 includes two arc-shaped recesses, and an arc-shaped protrusion is provided between the two arc-shaped recesses; two arc-shaped punches are provided in step S4, which are respectively aligned with the two arc-shaped recesses, and a recessed area that connects with the arc-shaped protrusion is provided between the two arc-shaped punches.

5. A method for manufacturing an aluminum electrolytic capacitor core according to claim 1, characterized in that, The electrode foil includes an anode foil and a cathode foil, and corresponding guide pins are connected to both the anode foil and the cathode foil. In step S5, an additional layer of electrolytic paper is added between the anode foil and the cathode foil.

6. A method for manufacturing an aluminum electrolytic capacitor core according to claim 5, characterized in that, In step S5, when the guide pin on the anode foil is about to come into contact with the cathode foil and the electrolytic paper, additional electrolytic paper is placed at the point where the guide pin comes into contact and is wound up simultaneously.

7. A method for manufacturing an aluminum electrolytic capacitor core according to claim 5, characterized in that, The additional electrolytic paper only covers the guide pin area on the anode foil.

8. A method for manufacturing an aluminum electrolytic capacitor core according to claim 5, characterized in that, During the initial winding, the electrolytic paper is stretched and folded at the starting point. During the winding process, the guide pins on the anode foil are aligned with the extra folded area of ​​the electrolytic paper.

9. A method for manufacturing an aluminum electrolytic capacitor core according to any one of claims 1-8, characterized in that, After the core winding is completed in step S5, an electronic tape is wrapped around the outermost ring of the core. The width of the electronic tape is smaller than the width of the electrolytic paper and larger than the width of the electrode foil.

10. A method for manufacturing an aluminum electrolytic capacitor core according to claim 9, characterized in that, The electronic tape is 1 mm narrower than the electrolytic paper, and the electronic tape is wrapped around the outer layer 1.5 times.

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