Ultra-thin solid aluminum electrolytic capacitors

Abstract

To provide an ultra-thin solid aluminum electrolytic capacitor with high heat resistance and vibration resistance. [Solution] The ultra-thin solid aluminum electrolytic capacitor includes an outer shell 1, an element 2, and a cover 4. An opening 101 is provided on one side of the outer shell, and a locking projection 102 is provided in the opening. The cover and the opening are integrally fitted by injection molding, and the element is sealed inside the outer shell. The cover includes a substrate 401, an inner plug 402, and a side sealing wall 403. The side sealing wall and the inner plug are vertically provided on the upper end surface of the substrate, the inner plug is located inside the side sealing wall, and the gap between the outer circumferential wall of the inner plug and the inner circumferential wall of the side sealing wall forms a groove 404, which is tightly coupled to the inner and outer structures of the opening. Two lead holes are symmetrically provided on the end surface of the inner plug, penetrating the cover. Leads 3 pass through the lead holes as external extraction electrodes. The lid is sealed by integrally fitting the lid and the outer shell's opening structure together by injection molding, which allows the requirements for heat resistance and vibration resistance to be met even with a reduced thickness.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum electrolytic capacitors, and particularly relates to an ultra-thin solid aluminum electrolytic capacitor.

Background Art

[0002] Solid aluminum electrolytic capacitors are mainly used in electronic products. As electronic products and electronic components become thinner, the capacitors are also becoming thinner. Although the structure and manufacturing process of conventional solid aluminum electrolytic capacitors have been improved and advanced, there are still technical bottlenecks that cannot be broken through in the design of thinner and smaller capacitors. The current chip-type solid aluminum electrolytic capacitor is manufactured by packaging the aluminum electrolytic capacitor, connecting the base based on the capacitor body, and then bending the leads. The structure and process of conventional solid aluminum electrolytic capacitors have the following disadvantages because they first enclose a rubber lid and then add a base. The current solid aluminum electrolytic capacitor is manufactured by covering the opening between the element and the outer shell with a plastic lid, extrusion molding, and shrink packaging. The thickness of the butyl rubber lid is the key to the height of the product. In order to meet the conditions of airtightness, heat resistance, and vibration resistance and prevent product defects caused by moisture intrusion and gas expansion, the minimum thickness of the rubber lid needs to be maintained at 1.5 mm or more. As a result, the minimum height limit of the entire solid aluminum electrolytic capacitor product is restricted. Currently, the industry can manufacture solid aluminum electrolytic capacitors with a minimum height of 4.2 mm, but solid aluminum electrolytic capacitors of this size cannot meet the customers' requirements for miniaturization. Breaking through this extreme thickness dimension has become a major problem in the industry.

Summary of the Invention

[0003] Therefore, there is a need to provide an ultra-thin solid aluminum electrolytic capacitor. By integrally fitting and sealing the opening structure of the lid and the outer shell by injection molding, the lid can meet the requirements for heat resistance and vibration resistance even with reduced thickness. A solid aluminum electrolytic capacitor using this lid breaks through the limits of product thinness and possesses high heat resistance and vibration resistance, achieving the effect of ultra-thin solid aluminum electrolytic capacitors.

[0004] The present invention solves the technical problem by the following technical means.

[0005] An ultra-thin solid aluminum electrolytic capacitor comprising an outer shell, an element, and a cover, wherein an opening is provided on one side of the outer shell, a locking projection is provided in the opening, the cover and the opening are integrally fitted by injection molding, the element is sealed inside the outer shell, the cover comprises a substrate, an inner plug, and a side sealing wall, the side sealing wall and the inner plug are vertically provided on the upper end surface of the substrate, the inner plug is located inside the side sealing wall, the gap between the outer circumferential wall of the inner plug and the inner circumferential wall of the side sealing wall forms a groove, the groove is tightly coupled to the inner and outer structures of the opening, and two lead holes are symmetrically provided on the end surface of the inner plug, penetrating the cover, and leads pass through the lead holes as external extraction electrodes.

[0006] Preferably, the lid is formed by injecting molten plastic into the cavity between the opening of the outer shell and the element, and tightly bonding the plastic to the inner and outer members of the opening.

[0007] Preferably, the outer edge of the upper end of the stopper is provided with a protruding convex edge structure, and the outer ring diameter of the convex edge structure is larger than the outer ring diameter of the stopper.

[0008] Preferably, the side wall of the convex edge structure is provided with an inwardly concave surface distributed along the circumferential direction, and the inwardly concave surface is in close contact with the inner wall of the constricted ring of the outer shell.

[0009] Preferably, a projection is provided on the inner wall of the side sealing wall at the end furthest from the substrate, and the projection is in close contact with the outer wall of the constricted ring of the outer shell.

[0010] Preferably, the groove portion includes a longitudinal groove and a transverse groove, the longitudinal groove and the transverse groove intersect and penetrate each other in an L-shape, the longitudinal groove is fitted into the side wall of the outer shell, and the transverse groove is fitted into the locking projection at the opening.

[0011] Preferably, two lead grooves are provided on the outer side of the bottom surface of the substrate, with one end of each lead groove communicating with the lead hole and the end furthest from the lead hole extending to the side wall of the substrate.

[0012] Preferably, a first spacer is provided between the end face of the inner plug and the element, and a second spacer is provided between the end face of the element and the top surface of the inner lumen of the outer shell.

[0013] Preferably, a clamping wall is provided extending from the end of the side sealing wall furthest from the substrate, and the inner wall of the clamping wall is tightly in contact with the outer wall of the outer shell.

[0014] Preferably, the lead includes a portion A, a welded portion, and a flattened portion, wherein portion A is a sheet-like structure and is connected to the element, the welded portion and the flattened portion are connected via the welded portion, and the flattened portion is provided with a bent portion.

[0015] The advantages and positive effects of the present invention are as follows: The ultra-thin solid aluminum electrolytic capacitor of the present invention can solve the problem that conventional aluminum electrolytic capacitors cannot be made thinner.

[0016] Compared to the prior art, the present invention has the following advantages. In this invention, by integrally fitting and sealing the opening of the lid and the outer shell by injection molding, the lid can satisfy the requirements for heat resistance and vibration resistance even with reduced thickness. Solid aluminum electrolytic capacitors to which this lid is applied break through the limits of product thinness and possess high heat resistance and vibration resistance, achieving an ultra-thinning effect for solid aluminum electrolytic capacitors. By applying the lid of the present invention, the difference in length between the aluminum foil and the electrolytic paper in the winding axis direction (i.e., the direction perpendicular to the winding direction) in the element is reduced to 0.5 mm. By adopting a design without the flattened structure of section B, the lead structure can be miniaturized. The overall height of the solid aluminum electrolytic capacitor can be controlled to 3.0 mm or less, breaking the minimum height limit of current products. Solid aluminum electrolytic capacitors to which this lid is applied can have their height significantly reduced while maintaining good heat resistance, vibration resistance, and sealing performance, thus achieving a thin product design. This invention meets the dimensional requirements for further thinning of electronic products, improves their sealing performance, reflow thermal stress resistance, and vibration resistance, and replaces the conventional sealing method of attaching a vibration-resistant base to the outside after sealing with a rubber cover. Furthermore, it extends the service life of solid aluminum electrolytic capacitors, simplifies the manufacturing process, makes operation convenient, reduces costs, and meets the needs of various production fields. By applying the cover of this invention, new application fields can be opened up for chip-type solid aluminum electrolytic capacitors, solid-liquid mixed aluminum electrolytic capacitors, and liquid aluminum electrolytic capacitors. [Brief explanation of the drawing]

[0017] To more clearly illustrate embodiments of the present invention or technical means of the prior art, the following drawings necessary for describing the embodiments or prior art are briefly introduced. As is clear, the following drawings are only a few embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0018] [Figure 1] This is a schematic cross-sectional view of the present invention. [Figure 2] This is a schematic diagram of the three-dimensional structure of the present invention. [Figure 3]This is a schematic diagram of the three-dimensional structure from another perspective of the present invention. [Figure 4] This is a schematic diagram of the three-dimensional structure of the lid of Embodiment 1 of the present invention. [Figure 5] This is a schematic cross-sectional view of the lid of the present invention. [Figure 6] This is a schematic cross-sectional view of Embodiment 2 of the present invention. [Figure 7] This is a schematic cross-sectional view of Embodiment 3 of the present invention. [Figure 8] This is a schematic diagram of the three-dimensional structure of the outer shell of the present invention. [Figure 9] These are schematic diagrams of the front and side structures of the lead of the present invention.

[0019] Explanation of the symbols 1. Outer shell; 2. Element; 3. Lead; 4. Cover; 5. First spacer; 6. Second spacer; 101. Opening; 102. Locking projection; 103. Constricted ring; 301. Part A; 302. Welded part; 303. Flat part; 304. Bent part; 401. Substrate; 402. Inner plug; 403. Side sealing wall; 404. Groove; 405. Lead hole; 4011. Lead groove; 4012. Corner cut part; 4021. Convex edge structure; 4022. Inner concave surface; 4031. Projection; 4032. Clamping wall; 4041. Longitudinal groove; 4042. Transverse groove. [Modes for carrying out the invention]

[0020] The embodiments of the present invention will be described in more detail with reference to the drawings. Hereinafter, the technical means in the embodiments of the present invention will be clearly and completely described by the drawings of the embodiments of the present invention. The following embodiments are only some embodiments of the present invention, not all embodiments. Hereinafter, the description of at least one exemplary embodiment is actually exemplary and does not limit the present invention and its application or use. Based on the embodiments of the present invention, those skilled in the art can obtain all other embodiments without creative efforts, and all of them are included in the protection scope of the present invention. In this specification, the orientation and positional relationship indicated by terms such as "upper", "lower", "bottom", "inner", "outer", etc. are based on the orientation and positional relationship shown in the attached drawings. "Part A" and "Part B" are the structural names of leads in the industry, and are only used to facilitate the description of the present invention and simplify the description, and do not intend to indicate or imply that the devices or elements mentioned must have a specific orientation and must be constructed and operated in a specific orientation. Therefore, it should not be construed as limiting the present invention.

[0021] Embodiment 1 The manufacturing process of the ultra-thin wound solid aluminum electrolytic capacitor according to this embodiment is as follows. S1 (Manufacture of Element 2): Cut out the positive aluminum foil, negative aluminum foil, and electrolytic paper in a predetermined size, connect the leads 3 to the positive aluminum foil and negative aluminum foil respectively, stack the positive aluminum foil, electrolytic paper, and negative aluminum foil alternately, wind and fix them to obtain Element 2. S2: Install Element 2 into the inner cavity of the outer shell 1, and use the sealing equipment to fold the opening 101 of the outer shell 1 inward to form the locking convex portion 102. S3: Transfer the outer shell 1 with Element 2 installed inside into the injection molding die, inject the molten plastic from the nozzle into the die by the screw or plug of the injection molding machine, and after cooling, obtain a solid aluminum electrolytic capacitor sealed with the lid 4.

[0022] As shown in Figures 1-4, an opening 101 is provided on one side of the outer shell 1, and a locking projection 102 is provided in the opening 101. The lid 4 and the opening 101 are integrally fitted by injection molding, sealing the element 2 inside the outer shell 1. The lid 4 includes a substrate 401, an inner plug 402, and a side sealing wall 403. The side sealing wall 403 and the inner plug 402 are vertically provided on the upper end surface of the substrate 401. The inner plug 402 is located inside the side sealing wall 403. A groove 404 is formed in the gap between the outer peripheral wall of the inner plug 402 and the inner peripheral wall of the side sealing wall 403. The groove 404 is tightly coupled to the internal and external structures of the opening 101. Two lead holes 405 are symmetrically provided on the end surface of the inner plug 402, penetrating the lid 4. Leads 3 pass through the lead holes 405 as external extraction electrodes.

[0023] Specifically, a solid aluminum electrolytic capacitor consists of an outer shell 1, an element 2, leads 3, and a cover 4. The cover 4 hermetically seals the element 2 inside the outer shell 1, preventing external moisture (water vapor) from entering the element 2 and maintaining a dry state between the inner cavity of the outer shell 1 and the element 2. This prevents the conductive polymer in the element 2 from reacting with moisture and causing failure. The opening 101 of the outer shell 1 is fitted to the cover 4 mainly by injection molding, creating a sealed space inside the outer shell 1, and the groove 404 is coupled to the outer shell 1. The inner plug 402 of the cover 4 is tightly coupled to the inner wall of the opening 101 of the outer shell 1 and the outer wall of the locking projection 102, sealing the inside of the opening 101. The side sealing wall 403 of the cover 4 is tightly coupled to the outer wall of the outer shell 1, sealing the outside. This improves sealing performance from both the inside and the outside. Furthermore, the connection between the locking projection 102 and the cover 4 prevents the solid aluminum electrolytic capacitor from deforming even in high-temperature and vibrating environments, and prevents the cover 4 from deforming and moving outward due to high temperature or high pressure, thereby improving high-temperature resistance and vibration resistance.

[0024] The upper end surface of the substrate 401 is connected to the lower end surface of the inner plug 402 and the side sealing wall 403, respectively, so that the substrate 401, inner plug 402, and side sealing wall 403 become one unit. This improves sealing performance and rigidity, and prevents deformation even when the substrate 401 is thin, less than 0.3 mm thick, under the high temperature of reflow. In addition, the substrate 401, inner plug 402, and side sealing wall 403 are joined together and integrally molded. The substrate 401 increases the support force and protects the lead 3. The integrated structure of the substrate 401 and inner plug 402 provides sealing performance and heat and vibration resistance, so that the lid 4 has both heat resistance and vibration resistance. The lid 4 has both heat resistance and vibration resistance without the need to add vibration-damping plates. Through injection fitting and integral sealing of the lid and the outer shell opening, the lid can meet the requirements for heat resistance and robustness even if its thickness is reduced. The inner plug 402 and the side sealing wall 403 are coaxially positioned. In this embodiment, preferably, the inner plug 402 has a cylindrical structure, the cross-section of the side sealing wall 403 has an annular structure, and the axes of the inner plug 402 and the side sealing wall 403 coincide. In another embodiment, the cross-sections of the inner plug 402 and the side sealing wall 403 may be polygonal. The overall height of the solid aluminum electrolytic capacitor can be controlled to 3.0 mm or less, exceeding the minimum height limit of current products. As a result, when this cover is applied to a solid aluminum electrolytic capacitor, it can have both heat resistance and vibration resistance. A solid aluminum electrolytic capacitor using this cover 4 can significantly reduce its height while maintaining good sealing, heat resistance, and vibration resistance, thus achieving a thinner product design.

[0025] The lid 4 is formed by injecting molten plastic into the cavity between the opening 101 of the outer shell 1 and the element 2, thereby tightly bonding the plastic to the internal and external components of the opening 101.

[0026] Specifically, after assembling the element 2 into the outer shell 1, the outer shell 1 is placed in an injection molding die. After the molten plastic reaches a predetermined temperature and pressure, the screw or plug of the injection molding machine injects the molten plastic from the nozzle between the outside of the opening 101 and the mold to form a cavity. After injection, a side sealing wall 403 is formed, and a cavity is formed between the inside of the opening 101 and the locking projection 102 and the element 2. After injection, a substrate 401 and an inner plug 402 are formed, and after cooling, an integrated lid 4 is obtained. The plastic is tightly bonded to the inner and outer members of the opening 101, and the lid 4 fits into the outer shell 1 and the opening 101 to form a single unit. The lid 4 hermetically seals the element 2 inside the outer shell. This results in a thin solid aluminum electrolytic capacitor.

[0027] A protruding convex edge structure 4021 is provided on the outer edge of the upper end of the inner plug 402. The outer ring diameter of the convex edge structure 4021 is larger than the outer ring diameter of the inner plug 402. Specifically, after injection molding is complete, the inner plug 402 is formed inside the opening 101. In this embodiment, since the outer shell 1 is cylindrical, the inner plug 402 is cylindrical and is tightly fitted to the inner wall of the outer shell 1. In other embodiments, the cross-sectional shape of the outer shell 1 may be rectangular or triangular, and the cross-sectional shape of the inner plug 402 used may also be a suitable rectangle or triangle. In addition, in this embodiment, the locking projection 102 at the opening 101 is folded inward, but in other embodiments, the locking projection 102 may be provided to be folded outward, which also allows the lid 4 to engage and improve heat resistance and robustness.

[0028] A protruding convex edge structure 4021 is provided on the outer edge of the upper end of the inner plug 402. The outer ring diameter of the convex edge structure 4021 is larger than the outer ring diameter of the inner plug 402. The outer peripheral side wall and the lower end surface of the convex edge structure 4021 form a stepped structure. The stepped structure engages with the locking projection 102, improving stability and heat-resistant sealing, and preventing the lid 4 from slipping when pressure expands at high temperatures. The outer peripheral side surface of the convex edge structure 4021 is tightly in contact with the inner peripheral wall of the outer shell 1, and the lower end surface of the convex edge structure 4021 is tightly in contact with the upper end surface of the locking projection 102 at the opening 101, improving the sealing effect.

[0029] The groove 404 includes a vertical groove 4041 and a horizontal groove 4042. The vertical groove 4041 and the horizontal groove 4042 intersect and penetrate each other in an L-shape. The vertical groove 4041 is fitted into the side wall of the outer shell 1, and the horizontal groove 4042 is fitted into the locking projection 102 at the opening 101.

[0030] Specifically, as shown in Figures 4-5, the groove 404 is formed when the lid 4 is injection molded by the fitting of the circumferential wall of the outer shell 1 and the locking projection 102. The groove 404 and the circumferential wall and locking projection 102 of the outer shell 1 are seamlessly in contact. The vertical groove 4041 and the horizontal groove 4042 intersect and penetrate in an L-shape, fitting tightly to the locking projection 102 of the opening 101 of the outer shell 1. This extends the path for external moisture to enter the interior, improving sealing and heat resistance, while the L-shaped structure improves structural stability, heat resistance, and vibration resistance.

[0031] Lead 3 includes section A 301, a welded section 302, and a flattened section 303. Section A 301 is a sheet-like structure and is connected to the element 2. The welded section 302 and the flattened section 303 are connected by the welded section 302. The flattened section 303 is provided with a bent section 304.

[0032] Specifically, when processing lead 3, section A 301 is a structure formed by crushing an aluminum pillar. The lower end of section A 301 is welded to a flattened section 303 via a welded section 302, which shortens the vertical length of lead 3. The flattened section 303 has a flattened structure, which reduces the vertical height. The structure of lead 3 is fitted and joined to the cover 4, which reduces the vertical height of both lead 3 and cover 4. Furthermore, since a bent section 304 is provided in advance on lead 3, there is no need to bend lead 3 again after injection molding of the cover 4, thus avoiding damage to the thinned solid aluminum electrolytic capacitor body structure due to secondary bending. Therefore, the structural design of lead 3 in the present invention provides the necessary conditions for thinning the product.

[0033] Two lead holes 405 are symmetrically provided on the end face of the inner plug 402, penetrating the lid 4. Leads 3 are passed through the lead holes 405 as external extraction electrodes. Two lead grooves 4011 are provided on the outer side of the bottom surface of the substrate 401. One end of the lead groove 4011 communicates with the lead holes 405, and the end furthest from the lead holes 405 extends to the side wall of the substrate 401.

[0034] Element 2 is formed by laminating and winding a positive electrode foil, electrolytic paper, and a negative electrode foil. The leads 3 are divided into positive electrode leads and negative electrode leads. The positive electrode leads are connected to the positive electrode foil, and the negative electrode leads are connected to the negative electrode foil. When the cover 4 is injection molded, the leads 3 are embedded in the cover 4 beforehand, and after injection molding, the leads 3 penetrate between the inner plug 402 and the substrate 401. The ends of the positive and negative electrode leads 3 that protrude from the substrate 401 are bent and tightly fitted into the lead grooves 4011. The leads 3 extend along the lead grooves 4011 to the side wall of the substrate 401 and are exposed. The portions of the positive and negative electrode leads 3 that are exposed from the substrate 401 are welded to the PCB board. The leads 3 are pulled out from element 2, penetrate the inner plug 402 and the substrate 401, and then welded to the PCB board. Since the plug 402 and the substrate 401 are integrally molded and possess heat resistance and vibration resistance, there is no need to separately fit a base, and the application conditions for heat resistance and vibration resistance of chip solid aluminum electrolytic capacitors can be met. Therefore, while the lid 4 is guaranteed to have good sealing heat resistance and vibration resistance, the total height of the lid 4 is reduced, and it can replace the conventional butyl rubber plug and base combination design. When the design of the lid 4 is applied to solid aluminum electrolytic capacitors, the difference in length between the aluminum foil and the electrolytic paper in the winding axis direction (i.e., the direction perpendicular to the winding direction) can be reduced to 0.5 mm, further reducing the total height of the solid aluminum electrolytic capacitor, and the cutting width of the aluminum foil can be set to 1.6 mm or less. In addition, since the substrate 401, plug 402, and side sealing wall 403 of the lid 4 of the present invention are integrally molded, based on the structure of the lid 4 of the present invention, the total thickness of the plug 402 can be reduced to 1.3 mm or less, and the thickness of the substrate 401 can be reduced to 0.3 mm or less. Based on the integrally molded structure of the substrate 401, the plug 402, and the side sealing wall 403, the total thickness of the plug 402 can be reduced to 1.3 mm or less, and the thickness of the substrate 401 can be reduced to 0.3 mm or less. The total height of the wound solid aluminum electrolytic capacitor after assembly can be controlled to 3.0 mm or less, exceeding the size limit, and the product is resistant to the effects of gas expansion after reflow soldering at high temperatures, maintaining heat resistance and shock resistance.

[0035] Example 2 The manufacturing process for the ultra-thin wound solid aluminum electrolytic capacitor according to this embodiment is as follows. S1 (Manufacturing of element 2): Cut out positive electrode aluminum foil, negative electrode aluminum foil, and electrolytic paper to the predetermined size. Connect leads 3 to the positive electrode aluminum foil and negative electrode aluminum foil respectively. Laminate the positive electrode aluminum foil, electrolytic paper, and negative electrode aluminum foil alternately, wind them up, and fix them in place to obtain element 2. S2: Element 2 is installed in the lumen of the outer shell 1, the opening 101 of the outer shell 1 is folded inward using a sealing device to form a locking projection 102, and the outer circumferential wall of the outer shell 1 is pressed using a necking roll to form a constricted ring 103. S3: The outer shell 1 with the element 2 installed inside is transferred to an injection molding die, molten plastic is injected into the die from the nozzle using the screw or plug of the injection molding machine, and after cooling, a solid aluminum electrolytic capacitor sealed with a lid 4 is obtained.

[0036] Figure 6 shows Embodiment 2 of the present invention. This embodiment is based on the embodiment. Specifically, the side wall of the convex edge structure 4021 is provided with an inner concave surface 4022 distributed along the circumferential direction, and the inner concave surface 4022 is in close contact with the inner wall of the constricted ring 103 in the outer shell 1.

[0037] Furthermore, a constricted ring 103 is provided near the opening 101 of the outer shell 1, which is formed to be constricted inward. This constricted ring 103 is formed by processing with a necking roll before injection molding of the lid 4. The inner wall of the constricted ring 103 is convex, and the outer wall of the constricted ring 103 is concave. During injection, the molten plastic immerses the convex inner wall of the constricted ring 103. After cooling, an inner concave surface 4022 is formed on the side wall of the convex edge structure 4021, distributed along the circumferential direction. The presence of the inner concave surface 4022 further extends the path for moisture to enter the interior, improving the sealing between the outer circumferential wall of the convex edge structure 4021 and the inner wall of the outer shell 1. The structural stability is further improved as the inner concave surface 4022 bonds to the inner wall of the constricted ring 103 of the outer shell 1.

[0038] A projection 4031 is provided on the inner wall of the side sealing wall 403 at the end furthest from the substrate 401. The projection 4031 is in close contact with the outer wall of the constricted ring 103 in the outer shell 1. Specifically, the side sealing wall 403 is a structure formed by injection molding into the cavity between the injection molding die and the outer wall of the outer shell 1. The outer wall of the constricted ring 103 is concave. During injection, the molten plastic immerses itself in the concave surface of the outer wall of the constricted ring 103, and after cooling, the projection 4031 is formed on the inner wall of the side sealing wall 403. The presence of the projection 4031 further extends the path for moisture to enter the interior, improving the sealing and vibration resistance between the inner circumferential wall of the side sealing wall 403 and the outer circumferential wall of the outer shell 1. Furthermore, the structural stability is further improved by the projection 4031 engaging with the concave surface of the outer wall of the constricted ring 103 in the outer shell 1.

[0039] Example 3 The manufacturing process for the ultra-thin wound solid aluminum electrolytic capacitor according to this embodiment is as follows. S1 (Manufacturing of element 2): Cut out positive electrode aluminum foil, negative electrode aluminum foil, and electrolytic paper to the predetermined size. Connect leads 3 to the positive electrode aluminum foil and negative electrode aluminum foil respectively. Laminate the positive electrode aluminum foil, electrolytic paper, and negative electrode aluminum foil alternately, wind them up, and fix them in place to obtain element 2. S2: Element 2 is installed in the lumen of the outer shell 1, the opening 101 of the outer shell 1 is folded inward using a sealing device to form a locking projection 102, and the outer circumferential wall of the outer shell 1 is pressed using a necking roll to form a constricted ring 103. S3: The outer shell 1 with the element 2 installed inside is transferred to an injection molding die, molten plastic is injected into the die from the nozzle using the screw or plug of the injection molding machine, and after cooling, a solid aluminum electrolytic capacitor sealed with a lid 4 is obtained.

[0040] Figure 7 shows Embodiment 3 of the present invention. This embodiment is based on Embodiment 2. Specifically, a clamping wall 4032 is provided extending from the end of the side sealing wall 403 furthest from the substrate 401. The inner wall of the clamping wall 4032 is tightly in contact with the outer wall of the outer shell 1.

[0041] The side sealing wall 403 and the clamping wall 4032 are integrally molded by injection molding. The inner circumferential wall of the clamping wall 4032 is tightly adhered to the outer circumferential wall of the outer shell 1. The total height of the side sealing wall 403 and the clamping wall 4032 is at least half the vertical height of the outer shell 1. This extends the path for moisture to enter the interior and improves the sealing performance. Furthermore, the coupling of the side sealing wall 403 to the clamping wall 4032 increases the load-bearing area, improving the heat resistance and mechanical stress resistance against high-temperature reflow, and thus improving vibration resistance.

[0042] As shown in Figure 2, the substrate 401 at the bottom of the lid 4 is rectangular, and its thickness may be set to 0.3 mm or less. One corner of the substrate 401 is provided as a corner cut portion 4012 to distinguish the positive and negative electrodes of the solid aluminum electrolytic capacitor. The entire lid 4 is injection molded as a single unit using a molding material such as epoxy resin. The substrate 401 is integrally molded by bonding it to the inner plug 402 and the side sealing wall 403. The interaction force is formed by the combination of the upper end surface of the substrate 401 and the support of the inner plug 402 and the side sealing wall 403, maintaining a stable structure, and preventing thermal deformation during reflow even if the substrate 401 is set to 0.3 mm or less. In conventional split-type base plates, if the thickness is 0.3 mm or less, deformation occurs at high temperatures, making it impossible to meet the requirements for sealing and heat resistance. Furthermore, after welding the substrate 401 of the present invention to the PCB board, the load-bearing area of ​​the substrate 401 is increased, preventing fracture of the lead 3 due to external force and improving vibration resistance. The substrate 401, the inner plug 402, and the side sealing wall 403 are designed as a single unit, replacing the conventional separate assembly method of rubber cover and base plate, and enabling the solid aluminum electrolytic capacitor to have excellent sealing, heat resistance, and vibration resistance even when its height is reduced to the absolute minimum.

[0043] As shown in Figure 7, a first spacer 5 is provided between the end face of the inner plug 402 and the element 2. A second spacer 6 is provided between the end face of the element 2 and the top surface of the inner lumen of the outer shell 1.

[0044] The first spacer 5 is positioned on the end face of the element 2 before injection. The lead 3 penetrates the first spacer 5, and during injection, the first spacer 5 blocks the molten plastic, preventing it from flowing into the interior of the element 2. This acts as a barrier and heat insulation, preventing plastic from entering between the positive electrode aluminum foil, negative electrode aluminum foil, electrode paper, and conductive polymer inside the element 2.

[0045] A second spacer 6 is provided between the end face of element 2 and the top surface of the inner cavity of the outer shell 1. Because the difference in length between the aluminum foil and the electrolytic paper in the winding axis direction (i.e., the direction perpendicular to the winding direction) is reduced to 0.5 mm, the distance between the end of the positive electrode aluminum foil and the inner wall of the outer shell 1 becomes shorter. By providing the second spacer 6, it is prevented that the end of the positive electrode aluminum foil will come into contact with the inner wall of the outer shell 1 and cause a short circuit, thereby improving safety. In this embodiment, the first spacer 5 and the second spacer 6 may be made of an insulating material with a thickness of 0.03-0.04 mm. In another embodiment, the first spacer 5 and the second spacer 6 may be made of an insulating heat transfer material, which can further improve heat resistance and heat dissipation.

[0046] The embodiments described in this invention are illustrative and not limiting. Therefore, the present invention is not limited to the embodiments described in the specific embodiments. Other embodiments obtained by those skilled in the art based on the technical means of the present invention are also covered by the present invention.

Claims

1. An ultra-thin solid aluminum electrolytic capacitor, It includes an outer shell (1), an element (2), and a cover (4), An opening (101) is provided on one side of the outer shell (1), and a locking projection (102) is provided in the opening (101). The lid (4) and the opening (101) are integrally fitted together by injection molding, and the element (2) is sealed inside the outer shell (1). The lid (4) includes a substrate (401), an inner plug (402), and a side sealing wall (403). A side sealing wall (403) and an inner plug (402) are vertically provided on the upper end surface of the substrate (401). The inner plug (402) is located inside the side sealing wall (403), and the gap between the outer peripheral wall of the inner plug (402) and the inner peripheral wall of the side sealing wall (403) forms a groove (404), and the groove (404) is tightly coupled to the inner and outer structures of the opening (101). An ultra-thin solid aluminum electrolytic capacitor characterized in that two lead holes (405) are symmetrically provided on the end face of the inner plug (402) and penetrate the lid (4), and leads (3) penetrate the lead holes (405) as external output electrodes.

2. The ultra-thin solid aluminum electrolytic capacitor according to claim 1, characterized in that the cover (4) is formed by injecting molten plastic into the cavity between the opening (101) of the outer shell (1) and the element (2), and tightly bonding the plastic to the inner and outer members of the opening (101).

3. The ultra-thin solid aluminum electrolytic capacitor according to claim 1, characterized in that a convex edge structure (4021) protruding outward is provided on the outer edge of the upper end of the inner plug (402), and the outer ring diameter of the convex edge structure (4021) is larger than the outer ring diameter of the inner plug (402).

4. The ultra-thin solid aluminum electrolytic capacitor according to claim 3, characterized in that the side wall of the convex edge structure (4021) is provided with an inner concave surface (4022) distributed along the circumferential direction, and the inner concave surface (4022) is in close contact with the inner wall of the constricted ring (103) of the outer shell (1).

5. The ultra-thin solid aluminum electrolytic capacitor according to claim 1, characterized in that a projection (4031) is provided on the inner wall of the side sealing wall (403) at the end furthest from the substrate (401), and the projection (4031) is in close contact with the outer wall of the constricted ring (103) of the outer shell (1).

6. The groove portion (404) includes a vertical groove (4041) and a horizontal groove (4042), the vertical groove (4041) and the horizontal groove (4042) intersect and penetrate each other in an L-shape, the vertical groove (4041) is fitted into the side wall of the outer shell (1), and the horizontal groove (4042) is fitted into the locking projection (102) at the opening (101), characterized in that the ultra-thin solid aluminum electrolytic capacitor according to claim 1.

7. The ultra-thin solid aluminum electrolytic capacitor according to claim 1, characterized in that two lead grooves (4011) are provided on the outer side of the bottom surface of the substrate (401), one end of each lead groove (4011) communicates with the lead hole (405), and the end furthest from the lead hole (405) extends to the side wall of the substrate (401).

8. The ultra-thin solid aluminum electrolytic capacitor according to claim 1, characterized in that a first spacer (5) is provided between the end face of the inner plug (402) and the element (2), and a second spacer (6) is provided between the end face of the element (2) and the top surface of the inner cavity of the outer shell (1).

9. An ultra-thin solid aluminum electrolytic capacitor according to claim 1, characterized in that a clamping wall (4032) extends from the end of the side sealing wall (403) furthest from the substrate (401), and the inner wall of the clamping wall (4032) is in close contact with the outer wall of the outer shell (1).

10. The lead (3) includes a portion A (301), a welded portion (302), and a flattened portion (303), wherein the portion A (301) is a sheet-like structure and is connected to the element (2), the welded portion (302) and the flattened portion (303) are connected via the welded portion (302), and the flattened portion (303) is provided with a bent portion (304), as described in claim 1.

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