Capacitor core package, low leakage stacked solid aluminum electrolytic capacitor and method of manufacturing the same

Abstract

The application relates to the technical field of solid aluminum electrolytic capacitors, in particular to a capacitor core package, a low-leakage laminated solid aluminum electrolytic capacitor and a preparation method thereof. The capacitor core package comprises N core subassemblies and a substrate. The core subassembly comprises a core and a U-shaped frame. The end of the opening of the U-shaped frame is provided with an anode lead-out piece. The other end of the U-shaped frame away from the opening is provided with a cathode lead-out part. In the application, the U-shaped frame with a thickness greater than that of the core is embedded with the capacitor core to form a core subassembly which can provide external skeleton support and protection for the core. The structure has higher rigidity than the single bare core and can resist the extrusion deformation of the resin on the core in the subsequent resin packaging process, thereby improving the phenomenon of increased leakage current caused by the deformation of the core. Furthermore, the insulation substrate with the metal lead-out parts embedded at both ends is used to realize the lead-out of the external pins. Compared with the traditional planar lead frame core package structure, the application is more compact and can effectively prevent the resin packaging material from being squeezed into the core package from the interlayer gap to damage the core.

Description

Technical Field

[0001] This invention relates to the field of solid aluminum electrolytic capacitor technology, specifically to capacitor cores, low-leakage multilayer solid aluminum electrolytic capacitors, and their preparation methods. Background Technology

[0002] Solid aluminum electrolytic capacitors include wound solid aluminum electrolytic capacitors and multilayer solid aluminum electrolytic capacitors. Both use conductive polymers as solid electrolytes. However, multilayer solid aluminum electrolytic capacitors adopt a structure of multiple cores stacked in parallel and a surface mount design. Compared with wound solid aluminum electrolytic capacitors, they are better suited to the development needs of the electronics and information industry for miniaturization and thinning of the whole machine.

[0003] The mature industrial manufacturing process for multilayer solid aluminum electrolytic capacitors is as follows: cut forming foil is divided into anode and cathode regions using barrier adhesive. A conductive polymer solid electrolyte layer, a conductive carbon paste layer, and a conductive silver paste layer are sequentially formed on the cathode region surface of the foil to form the capacitor core. Multiple capacitor cores are sequentially stacked on an external lead frame to form a capacitor core package, and the anode and cathode are led out. The capacitor core package is then encapsulated with resin, aged, and the leads are formed to obtain a solid aluminum electrolytic capacitor.

[0004] However, the capacitor core package prepared by the above process has the following problems: In the prior art, when the core is stacked on both sides of the planar strip lead frame, a gap is left between the anode tongue and the cathode tongue of the lead frame in the middle of the core package. During injection molding, the resin encapsulation material can easily be squeezed into this gap, causing compression deformation of the core and increasing leakage current.

[0005] Based on this, the present invention designs a capacitor core package, a low-leakage multilayer solid aluminum electrolytic capacitor, and a method for preparing the same, in order to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a capacitor core package, a low-leakage multilayer solid aluminum electrolytic capacitor, and a method for preparing the same, in order to solve the problem that when the core is stacked on both sides of a planar strip lead frame during the preparation of existing capacitor core packages, a gap is left between the anode tongue and cathode tongue of the lead frame in the middle of the core package. During injection molding, the resin encapsulation material can easily squeeze into this gap, causing compression deformation of the core and increasing leakage current.

[0007] To achieve the above objectives, the present invention provides a first technical solution as follows: A capacitor core package includes N core assemblies and a substrate; The core assembly includes a rectangular core and a U-shaped frame, wherein the thickness of the U-shaped frame is greater than the thickness of the core. An anode lead is provided at the opening end of the U-shaped frame, and a cathode lead is provided at the other end of the U-shaped frame away from the opening. The core is fixedly embedded between the inner walls of the U-shaped frame. The cathode part of the core is in contact with and electrically connected to the cathode lead, and the anode part of the core is in contact with and electrically connected to the anode lead. The substrate has an anode lead-out end and a cathode lead-out end embedded at opposite ends, and the two side surfaces of the anode lead-out end and the cathode lead-out end are exposed on the upper and lower surfaces of the substrate, respectively. N core components are stacked layer by layer on the substrate to form a core package. The bottommost anode lead and cathode lead are in contact with and electrically connected to the anode lead and cathode lead, respectively. The anode leads of two adjacent core components are in contact with and electrically connected to each other, and the cathode leads of two adjacent core components are in contact with and electrically connected to each other.

[0008] Preferably, the anode lead-out component includes two support parts and two anode lead-out parts. The two support parts are symmetrically fixed to the ends of the two side walls at the opening of the U-shaped frame. The two anode lead-out parts are respectively embedded in the two support parts. The cathode lead-out part is embedded in the end of the U-shaped frame away from the opening. Both the anode lead-out portion and the cathode lead-out portion have U-shaped cross-sections, and the openings of the U-shapes are set away from the openings of the U-shaped frame. The upper and lower surfaces of the anode lead-out portion are exposed above the upper and lower surfaces of the support portion, respectively. The lower surface of the anode lead-out portion is flush with the lower surface of the U-shaped frame, and the upper surface of the anode lead-out portion is lower than the upper surface of the U-shaped frame. The upper and lower surfaces of the cathode lead-out portion are exposed above the upper and lower surfaces of the U-shaped frame, respectively, and are flush with the upper and lower surfaces of the U-shaped frame.

[0009] Preferably, a metal gasket is fixedly connected to one side of the anode portion of the core, and the metal gasket is electrically connected to the anode portion of the core. When the core is embedded in the inner wall of the U-shaped frame, the two ends of the metal gasket are in contact with and electrically connected to the upper surfaces of the two anode leads, and the core is located on the side surface of the metal gasket near the anode leads.

[0010] Preferably, the metal gasket is connected to the anode part of the core and to the anode lead-out part by welding, and the cathode part of the core and the cathode lead-out part are connected by conductive silver paste.

[0011] Preferably, the anode lead-out end includes an anode horizontal portion, an anode connecting portion, and an anode terminal. The anode horizontal portion and the anode terminal are respectively disposed on opposite sides of the substrate and are flush with the sides of the substrate. The anode connecting portion passes through the substrate and is perpendicularly connected to and electrically connected to the anode horizontal portion and the anode terminal, respectively. The cathode lead-out end includes a cathode horizontal portion, a cathode connection portion, and a cathode terminal, and the structure and shape of the cathode lead-out end are consistent with those of the anode lead-out end.

[0012] Preferably, the thickness of the U-shaped frame is 120%-200% of the thickness of the cathode portion of the core.

[0013] The second technical solution provided by this invention is: A low-leakage multilayer solid aluminum electrolytic capacitor includes a resin shell and a capacitor core as described in the first technical solution. The resin shell covers the four sides and the top surface of the capacitor core, and the lower surface of the substrate, the anode terminal, and the cathode terminal of the capacitor core are exposed outside the resin shell.

[0014] The third technical solution provided by this invention is: A method for fabricating a low-leakage multilayer solid aluminum electrolytic capacitor, the method comprising the following steps: S1: Weld a metal gasket to one side of the anode portion of the core to obtain the second core; S2: The second core is embedded in the inner wall of the U-shaped frame, and the anode and cathode are led out respectively to obtain the core assembly; S3: According to the design number of layers, stack N core components layer by layer on the peripheral substrate, and perform anode and cathode lead-out respectively to obtain capacitor core package; S4: The capacitor is produced by encapsulating the capacitor core using epoxy molding compound.

[0015] Preferably, step S2 specifically comprises: S21. Bond and cure the end of the second core cathode part to the surface of the cathode lead-out part facing the opening of the U-shaped frame with conductive silver paste. S22. Weld the two ends of the metal gasket to the anode lead-out part of the U-shaped frame respectively; S23. Insulating adhesive is injected into the gap between the second core and the U-shaped frame and cured to obtain the core assembly.

[0016] Preferably, step S3 specifically comprises: S31. Apply conductive silver paste to the surface of the anode horizontal portion and the cathode horizontal portion of the substrate, and attach the side of the first core assembly away from the metal pad to the substrate, so that the two anode leads are electrically connected to the anode horizontal portion on the substrate and the cathode leads are electrically connected to the cathode horizontal portion on the substrate. S32. The side of the second core assembly away from the metal pad is bonded to the first core assembly with conductive silver paste, so that the two anode leads on the second core assembly are electrically connected to the metal pad of the first core assembly, and the cathode leads on the second core assembly are electrically connected to the cathode leads on the first core assembly. S33. Repeat S32 to bond the remaining core components to the second core component and to each other using conductive silver paste, and then cure the conductive silver paste to obtain the capacitor core package.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses a U-shaped frame with a thickness greater than the core thickness to embed the capacitor core. The resulting core assembly provides external skeleton support and protection for the core. This structure has higher rigidity than a single bare core and can resist the compression deformation of the core by the resin during the subsequent resin encapsulation process, thus improving the phenomenon of increased leakage current caused by core deformation. Furthermore, it uses an insulating substrate with metal lead-out components embedded at both ends to realize the lead-out of external pins. This is more compact than the core-pack structure of the traditional planar lead frame and effectively prevents the resin encapsulant from squeezing into the core-pack from the interlayer gap and damaging the core. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the core component in this invention; Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure; Figure 3 This is a schematic diagram of the connection structure between the core and the metal gasket in the core assembly of the present invention; Figure 4 This is a schematic diagram of the U-shaped frame in the core assembly of the present invention; Figure 5 This is a schematic diagram of the substrate structure in the core package of the present invention; Figure 6 This is a cross-sectional structural diagram of the core package of the present invention; Figure 7 This is a schematic diagram of the solid aluminum electrolytic capacitor of the present invention; Figure 8 This is a cross-sectional view of the solid aluminum electrolytic capacitor of the present invention. Figure 9This is a schematic diagram of the process for preparing the solid aluminum electrolytic capacitor of the present invention.

[0020] The attached diagram lists the components represented by each number as follows: 11. Core assembly; 12. U-shaped frame; 13. Cathode lead-out part; 14. Support part; 15. Anode lead-out part; 16. Metal gasket; 2. Substrate; 3. Anode lead-out end; 31. Anode horizontal part; 32. Anode connection part; 33. Anode terminal; 4. Cathode lead-out end; 5. Resin shell. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1-6 As shown, the first technical solution provided by the present invention is: A capacitor core package includes N core components 1 and a substrate 2; The core assembly 1 includes a rectangular core 11 and a U-shaped frame 12, with the thickness of the U-shaped frame 12 being greater than the thickness of the core 11. An anode lead-out is provided at the end of the opening of the U-shaped frame 12, and a cathode lead-out 13 is provided at the other end of the U-shaped frame 12 away from the opening. The core 11 is fixedly embedded between the inner walls of the U-shaped frame 12. The cathode part of the core 11 is in contact with and electrically connected to the cathode lead-out 13, and the anode part of the core 11 is in contact with and electrically connected to the anode lead-out. The substrate 2 has an anode lead-out end 3 and a cathode lead-out end 4 embedded at opposite ends, and the two side surfaces of the anode lead-out end 3 and the cathode lead-out end 4 are exposed above and below the substrate 2, respectively. N core components 1 are stacked layer by layer on the substrate 2 to form a core package. The anode lead and cathode lead 13 located at the bottom are in contact with and electrically connected to the anode lead 3 and the cathode lead 4, respectively. The anode leads of two adjacent core components 1 are in contact with and electrically connected to each other, and the cathode leads of two adjacent core components 1 are in contact with and electrically connected to each other.

[0023] Specifically, the anode lead-out component includes two support parts 14 and two anode lead-out parts 15. The two support parts 14 are symmetrically fixed to the ends of the two side walls at the opening of the U-shaped frame 12. The two anode lead-out parts 15 are respectively embedded in the two support parts 14. The cathode lead-out part 13 is embedded in the end of the U-shaped frame 12 away from the opening. Both the anode lead-out portion 15 and the cathode lead-out portion 13 have a U-shaped cross-section, and the openings of the U-shapes are both set in a direction away from the opening of the U-shaped frame 12. The upper and lower surfaces of the anode lead-out portion 15 are exposed above the upper and lower surfaces of the support portion 14, and the lower surface of the anode lead-out portion 15 is flush with the lower surface of the U-shaped frame 12. The upper surface of the anode lead-out portion 15 is lower than the upper surface of the U-shaped frame 12. The upper and lower surfaces of the cathode lead-out portion 13 are exposed above the upper and lower surfaces of the U-shaped frame 12 and are flush with the upper and lower surfaces of the U-shaped frame 12.

[0024] As described above, the core assembly under this structure has higher flatness than a single bare core. Combined with an insulating substrate with metal lead-out components embedded at both ends to achieve external pin lead-out, parallel stacking of cores is possible. The anode and cathode thicknesses of the core package are consistent, resulting in a more compact core package structure. This effectively prevents resin from squeezing into the interlayer gaps during injection molding, thus avoiding delamination. Furthermore, it avoids the problem in existing technologies where the cathode portion of the core is thicker than the anode portion. In multi-layer stacking, the core package exhibits a wedge shape with a narrow anode portion and a wide cathode portion. When manufacturing large-capacity products, as the number of layers increases, the thickness difference between the anode and cathode portions of the core package increases, leading to a greater tendency for interlayer delamination in the cathode portion of the core package, thus affecting the yield of industrial production.

[0025] Specifically, a metal gasket 16 is fixedly connected to one side of the anode portion of the core 11, and the metal gasket 16 is electrically connected to the anode portion of the core 11. When the core 11 is embedded in the inner wall of the U-shaped frame 12, the two ends of the metal gasket 16 are in contact with and electrically connected to the upper surfaces of the two anode leads 15 respectively, and the core 11 is located on the side surface of the metal gasket 16 near the anode leads 15.

[0026] As described above, by using metal gaskets to contact the anode lead-out portion, the embedded core can maintain balance, overcoming the thickness difference between the anode and cathode portions of the core. Furthermore, a U-shaped frame, in conjunction with the metal gaskets, pre-leads out the anode portion of the core, allowing for simple parallel connection of the anode portions of multi-layer cores using conductive silver adhesive. Each core's anode portion only experiences one impact during metal gasket welding. This solution addresses the problem in traditional processes where, with a large number of layers, the oxide film layer of the aluminum foil in the anode portion cracks with increasing welding counts, sometimes extending to the oxide film layer in the cathode region, leading to increased leakage current. Additionally, this solution also solves the problem in traditional processes where the welding strength of the outermost core decreases with more welding layers. It offers significant advantages in manufacturing multi-layer, high-capacity products.

[0027] Specifically, the metal pad 16 is connected to the anode part of the core 11 and to the anode lead-out part 15 by welding, and the cathode part of the core 11 is connected to the cathode lead-out part 13 by conductive silver paste.

[0028] Specifically, the anode lead-out end 3 includes an anode horizontal part 31, an anode connecting part 32, and an anode terminal 33. The anode horizontal part 31 and the anode terminal 33 are respectively disposed on opposite sides of the substrate 2 and are flush with the sides of the substrate 2. The anode connecting part 32 passes through the substrate 2 and is vertically connected to the anode horizontal part 31 and the anode terminal 33 respectively and is electrically connected. The cathode lead-out end 4 includes a cathode horizontal part, a cathode connection part and a cathode terminal, and the structure and shape of the cathode lead-out end 4 are the same as those of the anode lead-out end 3.

[0029] Specifically, the thickness of the U-shaped frame 12 is 120%-200% of the thickness of the cathode portion of the core 11.

[0030] As can be seen from the above description, using a U-shaped frame within this thickness range can not only ensure the rigidity of the core, but also avoid the overall product thickness being too high due to excessive thickness of the core components.

[0031] Please refer to Figure 7 and 8 As shown, the second technical solution provided by the present invention is: A high-capacity, low-leakage multilayer solid aluminum electrolytic capacitor includes a resin shell 5 and a capacitor core. The resin shell 5 covers the four sides and the top surface of the capacitor core, while the lower surface of the substrate 2, the anode terminal 33, and the cathode terminal in the capacitor core are exposed outside the resin shell 5.

[0032] As can be seen from the above description, the prepared capacitor can solve the problem of easy delamination of the cathode part of the traditional wedge-shaped core, which affects the industrial yield. It can also solve the problem that when the number of layers is large in the traditional process, the oxide film layer of the aluminum foil in the anode part will crack with the increase of welding times. In severe cases, the cracks may even extend to the oxide film layer in the cathode area, resulting in increased leakage current. In addition, it can also solve the problem that the more welding layers there are in the traditional process, the lower the welding firmness of the outermost core. It has significant advantages in the preparation of multi-layer, high-capacity products.

[0033] Please refer to Figure 9 As shown, the third technical solution provided by the present invention is: A method for fabricating a low-leakage multilayer solid aluminum electrolytic capacitor, the method comprising the following steps: S1: Weld a metal gasket 16 to one side of the anode portion of the core 11 to obtain a second core; S2: The second core is embedded in the inner wall of the U-shaped frame 12, and the anode and cathode are led out respectively to obtain the core assembly 1; S3: According to the design number of layers, stack N core components 1 layer by layer on the peripheral substrate 2, and perform anode lead-out and cathode lead-out respectively to obtain capacitor core package; S4: The capacitor is produced by encapsulating the capacitor core using epoxy molding compound.

[0034] Specifically, step S2 is as follows: S21. The end of the second core cathode part and the surface of the cathode lead-out part 13 facing the opening of the U-shaped frame 12 are bonded and cured with conductive silver paste. S22. Weld the two ends of the metal gasket 16 to the anode lead-out portion 15 of the U-shaped frame 12 respectively; S23. Insulating adhesive is injected into the gap between the second core and the U-shaped frame 12 and cured to obtain the core assembly 1.

[0035] Specifically, step S3 is as follows: S31. Apply conductive silver paste to the surfaces of the anode horizontal portion 31 and the cathode horizontal portion of the substrate 2, and attach the side of the first core assembly 1 away from the metal pad 16 to the substrate 2, so that the two anode leads 15 are electrically connected to the anode horizontal portion 31 on the substrate 2 and the cathode leads 13 are electrically connected to the cathode horizontal portion on the substrate 2. S32. The side of the second core assembly 1 away from the metal pad 16 is bonded to the first core assembly 1 with conductive silver glue, so that the two anode leads 15 on the second core assembly 1 are electrically connected to the metal pad 16 of the first core assembly 1, and the cathode leads 13 on the second core assembly 1 are electrically connected to the cathode leads 13 on the first core assembly 1. S33. Repeat S32 to bond the remaining core assembly 1 to the second core assembly 1 and to the remaining core assemblies 1 with conductive silver paste, and then cure the conductive silver paste to obtain the capacitor core package.

[0036] Embodiment 1 of the present invention is ( Figure 1-6 (as shown) like Figure 6 As shown: A capacitor core package includes three core components 1 and a substrate 2. The substrate 2 is made of insulating material, preferably epoxy laminated glass cloth board. like Figure 1 , 2As shown in Figure 5: The core assembly 1 includes a rectangular core 11 and a U-shaped frame 12, with the thickness of the U-shaped frame 12 being 160% of the thickness of the core 11. The core 11 includes an anode portion, a cathode portion, and an insulating barrier tape. The core 11 is made entirely of formed aluminum foil. An insulating barrier tape is coated on the formed aluminum foil to form an insulating barrier tape, dividing the anode area (anode portion) and the cathode area. A conductive polymer layer, a conductive carbon paste layer, and a conductive silver paste layer are sequentially prepared from the inside to the outside on the surface of the formed aluminum foil in the cathode area to obtain the cathode portion, thus obtaining the core 11. The opening end of the U-shaped frame 12 is provided with... The substrate 2 has an anode lead-out component and a cathode lead-out component 13 at the other end of the U-shaped frame 12 away from the opening. The core 11 is fixedly embedded between the inner walls of the U-shaped frame 12. The cathode part of the core 11 and the cathode lead-out component 13 are in contact and electrically connected through conductive silver paste. The anode part of the core 11 is in contact and electrically connected to the anode lead-out component. The substrate 2 has an anode lead-out end 3 and a cathode lead-out end 4 embedded at opposite ends. The two side surfaces of the anode lead-out end 3 and the cathode lead-out end 4 are exposed on the upper and lower surfaces of the substrate 2, respectively. The anode lead-out end 3 and the cathode lead-out end 4 are both made of copper and copper alloy. like Figure 4 As shown: In this embodiment, the anode lead-out component includes two support portions 14 and two anode lead-out portions 15. The two support portions 14 are symmetrically fixed to the ends of the two side walls at the opening of the U-shaped frame 12. The two anode lead-out portions 15 are respectively embedded in the two support portions 14. The cathode lead-out portion 13 is embedded in the end of the U-shaped frame 12 away from the opening. The cross-sectional shape of the anode lead-out portion 15 and the cathode lead-out portion 13 is U-shaped, and the opening of the U-shape is set in a direction away from the opening of the U-shaped frame 12. The upper and lower surfaces of the anode lead-out portion 15 are exposed above the upper and lower surfaces of the support portions 14, and the lower surface of the anode lead-out portion 15 is flush with the lower surface of the U-shaped frame 12. The upper surface of the anode lead-out portion 15 is lower than the upper surface of the U-shaped frame 12. The upper and lower surfaces of the cathode lead-out portion 13 are exposed above the upper and lower surfaces of the U-shaped frame 12 and are flush with the upper and lower surfaces of the U-shaped frame 12. like Figure 1 , 2 As shown in Figure 3: In this embodiment, a metal gasket 16 is fixedly connected to one side of the anode portion of the core 11 by welding, and the metal gasket 16 is electrically connected to the anode portion of the core 11. When the core 11 is embedded in the inner wall of the U-shaped frame 12, the two ends of the metal gasket 16 are respectively in contact with and electrically connected to the upper surfaces of the two anode leads 15 by welding, and the core 11 is located on the side surface of the metal gasket 16 near the anode leads 15.

[0037] In this embodiment, the anode lead-out end 3 includes an anode horizontal portion 31, an anode connecting portion 32, and an anode terminal 33. The anode horizontal portion 31 and the anode terminal 33 are respectively disposed on opposite sides of the substrate 2 and are flush with the sides of the substrate 2. The anode connecting portion 32 passes through the substrate 2 and is vertically connected to the anode horizontal portion 31 and the anode terminal 33 and is electrically conductive. The cathode lead-out end 4 includes a cathode horizontal portion, a cathode connecting portion, and a cathode terminal. The structure and shape of the cathode lead-out end 4 are the same as those of the anode lead-out end 3. The lower surface of the anode lead-out portion 15 is electrically connected to the anode horizontal portion 31 through conductive silver paste. The lower surface of the cathode lead-out portion 13 is electrically connected to the cathode horizontal portion through conductive silver paste. Meanwhile, in order to avoid short circuits between the anode and cathode caused by the diffusion of solder paste during soldering on the client board, the distance between the edges of the anode terminal 33 and the cathode terminal that are close to each other is 50%-70% of the length of the substrate 2. Furthermore, a tin layer is provided on the exposed surface of the anode terminal 33 and the cathode terminal on the substrate 2.

[0038] Embodiment 2 of the present invention is ( Figure 7-8 (as shown) A low-leakage multilayer solid aluminum electrolytic capacitor includes a resin shell 5 and a capacitor core as described in Embodiment 1. The resin shell 5 covers the four sides and the top surface of the capacitor core, and the lower surface of the substrate 2, the anode terminal 33 and the cathode terminal in the capacitor core are exposed outside the resin shell 5.

[0039] Embodiment 3 of the present invention is ( Figure 9 (as shown) A method for preparing a low-leakage multilayer solid aluminum electrolytic capacitor, used in Example 2, specifically includes the following steps: S1. Weld a metal gasket 16 to one side of the anode portion of the core 11 to obtain a second core. The welding method can be resistance welding, laser welding or ultrasonic welding. S2. The second core is embedded in the inner wall of the U-shaped frame 12 of the external device, and the anode and cathode are led out respectively to obtain the core assembly 1. S3. According to the designed number of layers, the three fabricated core components 1 are stacked layer by layer on the peripheral substrate 2, and the anode and cathode are led out respectively to form a capacitor core package. S4: The capacitor is produced by encapsulating the capacitor core using epoxy molding compound.

[0040] In this embodiment, the preparation process of the core 11 is as follows: the aluminum foil is punched into a rectangle, a barrier adhesive is coated (to form an insulating barrier tape) to divide the anode area (i.e., the anode part) and the cathode area, and then a conductive polymer layer, a conductive carbon paste layer and a conductive silver paste layer are formed sequentially on the surface of the cathode area to prepare the cathode part and obtain the core 11. In this embodiment, the specific embedding process of S2 is as follows: S21. The end of the cathode part of the second core is bonded and cured with conductive silver paste to the surface of the cathode lead-out part 13 facing the opening of the U-shaped frame 12. S22. Weld the two ends of the metal gasket 16 to the anode lead-out part 15 of the U-shaped frame 12 respectively. The welding method can be resistance welding, laser welding, or ultrasonic welding. S23. Insulating adhesive is injected into the gap between the second core and the U-shaped frame 12 and cured to obtain the core assembly 1; In this embodiment, the specific stacking process of S3 is as follows: S31. Apply conductive silver paste to the surfaces of the anode horizontal portion 31 and the cathode horizontal portion of the substrate 2, and attach the side of the first core assembly 1 away from the metal pad 16 to the substrate 2, so that the two anode leads 15 are electrically connected to the anode horizontal portion 31 on the substrate 2 and the cathode leads 13 are electrically connected to the cathode horizontal portion of the substrate 2. S32. The side of the second core assembly 1 away from the metal pad 16 is bonded to the first core assembly 1 with conductive silver glue, so that the two anode leads 15 on the second core assembly 1 are electrically connected to the metal pad 16 of the first core assembly 1, and the cathode leads 13 on the second core assembly 1 are electrically connected to the cathode leads 13 on the first core assembly 1. S33. Repeat S32 to bond the third core component 1 to the second core component 1 with conductive silver paste, and then cure the conductive silver paste to obtain the capacitor core package.

[0041] In this invention, a U-shaped frame with a thickness greater than the core thickness is used to embed the capacitor core. The anode of the core is electrically connected to two U-shaped anode leads at one end of the U-shaped frame opening via metal gaskets, and the cathode of the core is electrically connected to one U-shaped cathode lead at the other end of the U-shaped frame via conductive silver paste. Considering the difference in thickness between the anode and cathode portions of the core, a thinner support portion is provided at the opening of the U-shaped frame to reserve space for the thickness of the anode portion and the metal gaskets, allowing the core to be flatly positioned in the middle of the U-shaped frame. This structure has higher flatness than a single bare core, enabling parallel stacking of the cores and ensuring that the anode and cathode thicknesses of the capacitor core are consistent. This solves the problem of easy delamination of the cathode portion in traditional wedge-shaped cores, which affects the industrial yield. Secondly, the U-shaped frame outside the core provides external skeleton support and protection for the core. This structure has higher rigidity than a single bare core, and can resist the compression deformation of the core by the resin during subsequent resin encapsulation, improving... The invention addresses the issue of increased leakage current caused by core deformation. It utilizes an insulating substrate with embedded metal lead-out components at both ends to facilitate the lead-out of external pins. This design is more compact than traditional planar lead frame core-pack structures, effectively preventing resin encapsulant from seeping into the core-pack and damaging the core. Furthermore, the invention employs a U-shaped frame with metal pads to pre-lead out the anode portion of the core, allowing for simple parallel lead-out of the anode portions of multi-layer cores via conductive silver adhesive bonding. Each anode portion of the core is only subjected to one impact during metal pad welding. This solution solves the problem in traditional processes where, with a large number of layers, the oxide film layer of the aluminum foil on the anode portion cracks with increasing welding counts, sometimes extending to the oxide film layer in the cathode region, leading to increased leakage current. Additionally, this solution addresses the issue in traditional processes where the weld strength of the outermost core decreases with increasing weld layers, offering significant advantages in manufacturing multi-layer, high-capacity products.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A capacitor core package, characterized in that: It includes N core components (1) and a substrate (2); The core assembly (1) includes a rectangular core (11) and a U-shaped frame (12), and the thickness of the U-shaped frame (12) is greater than the thickness of the core (11). An anode lead is provided at the end of the opening of the U-shaped frame (12), and a cathode lead (13) is provided at the other end of the U-shaped frame (12) away from the opening. The core (11) is fixedly embedded between the inner walls of the U-shaped frame (12). The cathode part of the core (11) is in contact with and electrically connected to the cathode lead (13), and the anode part of the core (11) is in contact with and electrically connected to the anode lead. The substrate (2) has an anode lead-out end (3) and a cathode lead-out end (4) respectively embedded at its opposite ends, and the two side surfaces of the anode lead-out end (3) and the cathode lead-out end (4) are exposed on the upper and lower surfaces of the substrate (2) respectively. N core components (1) are stacked layer by layer on the substrate (2) to form a core package, and the anode lead and cathode lead (13) at the bottom are in contact with and electrically connected to the anode lead (3) and the cathode lead (4) respectively. The anode leads of two adjacent core components (1) are in contact with and electrically connected to each other, and the cathode leads of two adjacent core components (1) are in contact with and electrically connected to each other. The anode lead-out component includes two support parts (14) and two anode lead-out parts (15). The two support parts (14) are symmetrically fixed to the ends of the two side walls at the opening of the U-shaped frame (12). The two anode lead-out parts (15) are respectively embedded in the two support parts (14). The cathode lead-out part (13) is embedded in the end of the U-shaped frame (12) away from the opening. The cross-sectional shape of the anode lead-out part (15) and the cathode lead-out part (13) is U-shaped, and the opening of the U-shape is set away from the opening of the U-shaped frame (12). The upper and lower surfaces of the anode lead-out part (15) are exposed above the upper and lower surfaces of the support part (14), and the lower surface of the anode lead-out part (15) is flush with the lower surface of the U-shaped frame (12). The upper surface of the anode lead-out part (15) is lower than the upper surface of the U-shaped frame (12). The upper and lower surfaces of the cathode lead-out part (13) are exposed above the upper and lower surfaces of the U-shaped frame (12) and are flush with the upper and lower surfaces of the U-shaped frame (12). A metal gasket (16) is fixedly connected to one side of the anode part of the core (11), and the metal gasket (16) is electrically connected to the anode part of the core (11). When the core (11) is embedded in the inner wall of the U-shaped frame (12), the two ends of the metal gasket (16) are in contact with and electrically connected to the upper surfaces of the two anode leads (15), and the core (11) is located on the side surface of the metal gasket (16) near the anode leads (15).

2. The capacitor core package according to claim 1, characterized in that: The metal pad (16) is connected to the anode part of the core (11) and to the anode lead-out part (15) by welding. The cathode part of the core (11) and the cathode lead-out part (13) are connected by conductive silver paste.

3. A capacitor core package according to claim 1, characterized in that: The anode lead-out end (3) includes an anode horizontal part (31), an anode connecting part (32) and an anode terminal (33). The anode horizontal part (31) and the anode terminal (33) are respectively disposed on opposite sides of the substrate (2) and are flush with the sides of the substrate (2). The anode connecting part (32) passes through the substrate (2) and is vertically connected to the anode horizontal part (31) and the anode terminal (33) respectively and is electrically connected. The cathode lead-out end (4) includes a cathode horizontal part, a cathode connection part and a cathode terminal, and the structure and shape of the cathode lead-out end (4) are consistent with those of the anode lead-out end (3).

4. A capacitor core package according to claim 1, characterized in that: The thickness of the U-shaped frame (12) is 120%-200% of the thickness of the cathode part of the core (11).

5. A low-leakage multilayer solid aluminum electrolytic capacitor, characterized in that: The capacitor includes a resin shell (5) and a capacitor core package as described in any one of claims 1-4, wherein the resin shell (5) covers the four sides and the top surface of the capacitor core package, and the bottom surface of the substrate (2), the anode terminal (33) and the cathode terminal in the capacitor core package are exposed outside the resin shell (5).

6. A method for preparing a low-leakage multilayer solid aluminum electrolytic capacitor as described in claim 5, characterized in that: The preparation method includes the following steps: S1: Weld a metal gasket (16) to one side of the anode portion of the core (11) to obtain a second core; S2: The second core is embedded in the inner wall of the U-shaped frame (12), and the anode and cathode are led out respectively to obtain the core assembly (1). S3: According to the design number of layers, stack N core components (1) layer by layer on the substrate (2) of the peripheral device, and perform anode lead-out and cathode lead-out respectively to obtain capacitor core package; S4: The capacitor is produced by encapsulating the capacitor core using epoxy molding compound.

7. The method for preparing a low-leakage multilayer solid aluminum electrolytic capacitor according to claim 6, characterized in that: Step S2 specifically involves: S21. The end of the second core cathode part and the surface of the cathode lead-out part (13) facing the opening of the U-shaped frame (12) are bonded and cured with conductive silver glue; S22. Weld the two ends of the metal gasket (16) to the anode lead-out part (15) of the U-shaped frame (12) respectively; S23. Insulating adhesive is injected into the gap between the second core and the U-shaped frame (12) and cured to obtain the core assembly (1).

8. The method for preparing a low-leakage multilayer solid aluminum electrolytic capacitor according to claim 7, characterized in that: Step S3 specifically involves: S31. Apply conductive silver paste to the surface of the anode horizontal portion (31) and cathode horizontal portion of the substrate (2), and attach the side of the first core assembly (1) away from the metal pad (16) to the substrate (2), so that the two anode leads (15) are electrically connected to the anode horizontal portion (31) on the substrate (2) and the cathode leads (13) are electrically connected to the cathode horizontal portion on the substrate (2). S32. The side of the second core assembly (1) away from the metal pad (16) is bonded to the first core assembly (1) with conductive silver paste, so that the two anode leads (15) on the second core assembly (1) are electrically connected to the metal pad (16) of the first core assembly (1) and the cathode leads (13) on the second core assembly (1) are electrically connected to the cathode leads (13) on the first core assembly (1). S33. Repeat S32 to bond the remaining core assembly (1) to the second core assembly (1) and to the remaining core assembly (1) with conductive silver paste, and cure the conductive silver paste to obtain the capacitor core package.

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