Metal-encapsulated stacked solid aluminum electrolytic capacitor and manufacturing method therefor

Abstract

Disclosed in the present invention are a metal-encapsulated stacked solid aluminum electrolytic capacitor and a manufacturing method therefor. The metal‑encapsulated stacked solid aluminum electrolytic capacitor comprises an element stack, an anode metal can, a cathode metal can, and an annular coating layer; the anode metal can and the cathode metal can are both rectangular open-ended structures, and the two open ends of the anode metal can and the cathode metal can are fitted together and are hermetically connected to form a housing; and the annular coating layer is arranged on the outer peripheral surfaces of the housing. In the solid aluminum electrolytic capacitor of the present invention, a pair of open-ended metal cans that match each other are fitted to encapsulate a pre-manufactured element stack, forming a capsular structure, and the end portions of the cans are respectively electrically connected to an anode portion and a cathode portion of the element stack to lead out an anode and a cathode, thereby realizing the function of external terminals, achieving better hermeticity compared with resin encapsulation, helping improve the humidity resistance and heat resistance of the product, being more suitable for applications in harsh environments, such as high-temperature and high-humidity environments, and further ensuring hermetic encapsulation in combination with coverage of a joint by an annular insulating coating layer.

Description

A metal-encapsulated multilayer solid aluminum electrolytic capacitor and its preparation method Technical Field

[0001] This invention relates to the field of aluminum electrolytic capacitor technology, specifically to a metal-encapsulated multilayer solid aluminum electrolytic capacitor and its preparation method. Background Technology

[0002] Multilayer solid aluminum electrolytic capacitors use highly conductive polymer materials as the solid electrolyte and employ a core-pack structure with multiple cores stacked in parallel. Epoxy resin is used as the encapsulant to protect the core pack while shaping the finished product into a square structure suitable for surface mounting. Compared to traditional liquid aluminum electrolytic capacitors, multilayer solid aluminum electrolytic capacitors offer advantages such as superior basic electrical performance, smaller size, longer lifespan, and enhanced environmental friendliness and safety, better meeting the miniaturization, thinner profile, and higher speed requirements of the electronics and information industry.

[0003] Currently, the common process for manufacturing multilayer solid aluminum electrolytic capacitors is as follows: Cut formation foil is divided into anode and cathode regions using barrier adhesive. A conductive polymer solid electrolyte layer, a conductive carbon paste layer, and a silver paste layer are sequentially formed on the cathode region surface of the foil to form a core. Multiple cores are stacked on the upper and lower sides of an external lead frame by welding the anode portions and bonding the cathode portions with conductive silver paste to form a core package, completing the anode and cathode lead-out. Then, using a mold, the core package is injection molded with epoxy resin encapsulant. Leads extend from the middle of both ends of the core package out of the resin shell and are bent a second time towards the bottom to form external terminals. However, resin encapsulation is a non-hermetic structure, making it susceptible to moisture or corrosive gases and liquids penetrating the capacitor's interior under harsh environments such as high temperature and high humidity, leading to performance degradation or even failure. Therefore, this invention designs a metal-encapsulated multilayer solid aluminum electrolytic capacitor and its manufacturing method to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a metal-encapsulated multilayer solid aluminum electrolytic capacitor and its preparation method, so as to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides the following first technical solution:

[0006] A metal-encapsulated stacked solid aluminum electrolytic capacitor, comprising a core pack, an anode metal case, a cathode metal case and an annular coating layer, wherein both the anode metal case and the cathode metal case have a square open structure, the two open ends of the anode metal case and the cathode metal case are sleeved with each other and hermetically connected to form an outer casing, the ends of the anode metal case and the cathode metal case that are away from each other are an anode end and a cathode end respectively, the core pack is installed in the outer casing, the anode region of the core pack is electrically connected to the anode end, the cathode region of the core pack is electrically connected to the cathode end, and the annular coating layer is arranged on the outer peripheral surface of the outer casing.

[0007] Preferably, the material of the annular coating layer is a polymer insulating material.

[0008] Preferably, the core pack comprises N cores and N+1 metal gaskets stacked alternately in sequence, the core comprises an anode part, a cathode part and barrier glue, the metal gaskets are fixedly connected and electrically connected with the anode part of the core to form the anode region of the core pack, and the cathode parts of each of the cores are fixedly connected and electrically connected to form the cathode region of the core pack.

[0009] Preferably, the anode part of the core and the metal gasket are fixedly connected by welding, and the cathode parts of each of the cores are fixedly connected by conductive silver adhesive.

[0010] Preferably, the anode metal case comprises an anode tube body with an open end, the other end of the anode tube body is the anode end, the cathode metal case comprises a first cathode tube body and a second cathode tube body that are connected, the cross section of the first cathode tube body is smaller than that of the second cathode tube body, an open end is arranged at the end of the first cathode tube body, the end of the second cathode tube body is the cathode end, when the anode metal case and the cathode metal case are sleeved with each other, the first cathode tube body is inserted into the anode tube body, and the end of the anode tube body abuts against the end of the second cathode tube body.

[0011] Preferably, the outer surface and open edge of the anode tube body are covered with an insulating coating, and the outer surfaces of the first cathode tube body and the second cathode tube body, the open portion of the first cathode tube body, and the inner surface area of the first cathode tube body near the open edge are covered with an insulating coating.

[0012] Preferably, tin layers are provided on the outer surfaces of the anode end and the cathode end.

[0013] Preferably, the capacitor further comprises two symmetrically arranged pins, the cross-sectional shape of the pins is "匚"-shaped, the two pins are respectively closely attached to the outer surfaces of the anode end and the cathode end, and cover a partial region of the annular coating layer near the anode end and the cathode end, the two pins are respectively electrically connected to the anode end and the cathode end, and tin layers are provided on the outer surfaces of both of the two pins.

[0014] The present invention provides the following second technical solution:

[0015] A preparation method of a metal-packaged stacked solid aluminum electrolytic capacitor, comprising the following steps:

[0016] S1: punching and cutting etched aluminum foil into a rectangle, coating a barrier adhesive to form an anode part and a core cathode region, then sequentially forming a conductive polymer layer, a conductive carbon paste layer and a conductive silver paste layer on the surface of the core cathode region, preparing a cathode part to obtain a core;

[0017] S2: alternately arranging the anode parts of N cores and N+1 rectangular metal spacers, then achieving fixed connection between the anode parts and the metal spacers and electrical connection between the anode parts by welding, and bonding and curing the cathode parts of the N cores through conductive silver adhesive to achieve fixed connection and electrical connection between the cathode parts, so as to obtain a core pack;

[0018] S3: bonding the cathode region of the core pack into an external cathode metal case through conductive silver adhesive, so that the cathode region of the core pack is electrically connected with the cathode metal case, and the anode region of the core pack is exposed out of the opening edge of the cathode metal case, wherein the outer surface, the opening edge and the inner surface area adjacent to the opening edge of the cathode metal case are covered with an insulating coating;

[0019] S4: coating an insulating sealant on the outer surface of the first cathode tube body of the cathode metal case, sleeving an external anode metal case matching the cathode metal case with the cathode metal case to form an airtight connection, meanwhile filling conductive silver adhesive between the anode region of the core pack and the anode metal case to enable the anode region of the core pack and the anode metal case to form electrical connection, so as to prepare a first capacitor semi-finished product, wherein the outer surface and the opening edge surface of the anode metal case are covered with an insulating coating;

[0020] S5: wrapping an annular coating layer on the peripheral outer surface of the first capacitor semi-finished product, and exposing the anode end and the cathode end to prepare a second capacitor semi-finished product;

[0021] S6: removing the insulating coating on the surfaces of the anode end and the cathode end of the second capacitor semi-finished product, and then forming a tin layer on the surfaces of the anode end and the cathode end to prepare the capacitor.

[0022] Preferably, said step S6 can also be: removing the insulating coating on the surfaces of the anode end and the cathode end of the second capacitor semi-finished product, then welding a C-shaped pin respectively on the surfaces of the anode end and the cathode end, the two pins being arranged opposite to each other, covering a partial area of the annular coating layer adjacent to the anode end and the cathode end, and finally forming a tin layer on the outer surface of the pins to prepare the capacitor.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The solid aluminum electrolytic capacitor of the present invention encapsulates a pre-fabricated core package by using a pair of mutually cooperating open metal tubes to form a capsule structure. The ends of the tubes are electrically connected to the anode and cathode portions of the core package to lead out the anode and cathode, realizing the function of external terminals. It has better airtightness than resin encapsulation, which is beneficial to improving the product's moisture and heat resistance performance. It is more suitable for applications in harsh environments such as high temperature and high humidity. In addition, the annular insulating film layer covers the joint to further ensure airtight encapsulation.

[0025] 2. In the manufacturing process of the capacitor of the present invention, the airtightness of the encapsulation is ensured by setting an insulating sealant at the junction of the tube and shell and setting an annular insulating film layer on the outside of the tube and shell; the outer surface of the metal tube and shell, the open edge and the inner surface near the open edge are provided with an insulating coating to prevent short circuit, so as to achieve electrical non-conductivity between the anode tube and the cathode tube and shell. Attached Figure Description

[0026] 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.

[0027] Figure 1 is a schematic diagram of the structure of the solid aluminum electrolytic capacitor of the present invention;

[0028] Figure 2 is a cross-sectional view of the solid aluminum electrolytic capacitor of the present invention;

[0029] Figure 3 is a schematic diagram of the core package in the solid aluminum electrolytic capacitor of the present invention;

[0030] Figure 4 is a schematic diagram of the structure of the anode metal tube shell in the solid aluminum electrolytic capacitor of the present invention;

[0031] Figure 5 is a schematic diagram of the cathode metal tube shell in the solid aluminum electrolytic capacitor of the present invention.

[0032] Figure 6 is a schematic diagram of the solid aluminum electrolytic capacitor of the present invention after adding pins.

[0033] Figure 7 is a flowchart of the preparation method of the solid aluminum electrolytic capacitor of the present invention.

[0034] The attached diagram lists the components represented by each number as follows:

[0035] 1. Core package; 11. Core; 111. Anode section; 112. Cathode section; 113. Barrier adhesive; 12. Metal gasket; 2. Anode metal tube shell; 21. Anode end; 22. Anode tube body; 3. Cathode metal tube shell; 31. Cathode end; 32. First cathode tube body; 33. Second cathode tube body; 4. Annular coating layer; 5. Lead. Detailed Implementation

[0036] 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.

[0037] Please refer to Figures 1-7. One specific technical solution provided by this invention is as follows:

[0038] As shown in Figures 1 and 2, a metal-encapsulated multilayer solid aluminum electrolytic capacitor includes a core 1, an anode metal shell 2, a cathode metal shell 3, and an annular coating layer 4. Both the anode metal shell 2 and the cathode metal shell 3 are square open structures, and the two openings of the anode metal shell 2 and the cathode metal shell 3 are nested together and airtightly connected to form an outer shell. The ends of the anode metal shell 2 and the cathode metal shell 3 that are furthest from each other are the anode end 21 and the cathode end 31, respectively. The core 1 is installed inside the outer shell, and the anode region of the core 1 is electrically connected to the anode end 21, and the cathode region of the core 1 is electrically connected to the cathode end 31. The annular coating layer 4 is disposed on the outer surface of the outer shell, and the material of the annular coating layer 4 is a high-molecular insulating material, such as polyimide. A tin layer is disposed on the outer surface of the anode end 21 and the cathode end 31, which facilitates the soldering of the capacitor.

[0039] As shown in Figures 2 and 3, in this embodiment, the core package 1 includes four cores 11 and five metal pads 12 stacked alternately in sequence. The core 11 includes an anode portion 111, a cathode portion 112, and a barrier adhesive 113. The metal pads 12 are fixedly connected to the anode portion 111 of the core 11 and electrically connected to form the anode region of the core package 1. The cathode portions 112 of each core 11 are fixedly connected to each other and electrically connected to form the cathode region of the core package 1. The cathode portion of the core 11 consists of a chemically formed foil, a conductive polymer layer, a conductive carbon paste layer, and a conductive silver paste layer from the inside out. The metal pads 12 are made of copper and copper alloys.

[0040] In this embodiment, the anode portion 111 of the core 11 is fixedly connected to the metal pad 12 by welding, and the cathode portions 112 of each core 11 are fixedly connected to each other by conductive silver paste.

[0041] As shown in Figures 4 and 5, in this embodiment, the anode metal case 2 includes an anode tube body 22 with an open opening at one end, and the other end of the anode tube body 22 is an anode end 21; the cathode metal case 3 includes a connected first cathode tube body 32 and a second cathode tube body 33, the cross-section of the first cathode tube body 32 is smaller than that of the second cathode tube body 33, the end of the first cathode tube body 32 is provided with an open opening, and the end of the second cathode tube body 33 is a cathode end 31. When the anode metal case 2 and the cathode metal case 3 are sleeved with each other, the first cathode tube body 32 is inserted into the anode tube body 22, the end of the anode tube body 22 abuts against the end of the second cathode tube body 33, and the main material of the anode metal case 2 and the cathode metal case 3 is copper and copper alloys.

[0042] In this embodiment, the outer surface and the opening edge of the anode tube body 22 are covered with an insulating coating; the outer surfaces of the first cathode tube body 32 and the second cathode tube body 33, the opening of the first cathode tube body 32, and the inner surface area of the first cathode tube body 32 near the opening edge are covered with an insulating coating.

[0043] As shown in Figure 6, in this embodiment, in order to further increase the area of the pins and improve the welding firmness, the capacitor further includes two symmetrically arranged pins 5, and the cross-sectional shape of the pins 5 is "匚"-shaped. The two pins 5 are respectively closely attached to the outer surfaces of the anode end 21 and the cathode end 31, and cover a partial area of the annular coating film 4 near the anode end 21 and the cathode end 31. The two pins 5 are respectively electrically connected to the anode end 21 and the cathode end 31, and a tin layer is provided on the outer surface of each of the two pins 5.

[0044] As shown in Figure 7, the specific preparation process of the above capacitor is as follows:

[0045] A preparation method of a metal-packaged laminated solid aluminum electrolytic capacitor comprises the following steps:

[0046] S1: Punching and cutting formed aluminum foil into rectangles, coating barrier adhesive 113 to form an anode part 111 and a core cathode area, then sequentially forming a conductive polymer layer, a conductive carbon paste layer and a conductive silver paste layer on the surface of the core cathode area to prepare a cathode part 112, thus obtaining a core 1;

[0047] S2: Alternately arranging the anode parts 111 of four cores 11 and five rectangular metal spacers 12, then realizing the fixed connection between the anode parts 111 and the metal spacers 12 and the electrical connection between the anode parts 111 by welding, and realizing the fixed connection and electrical connection between the cathode parts 112 of N cores 11 by bonding and curing through conductive silver adhesive, thus obtaining a core package 1;

[0048] S3. The cathode area of ​​the core package 1 is bonded to the external cathode metal tube shell 3 with conductive silver paste, so that the cathode area of ​​the core package 1 and the cathode metal tube shell 3 are electrically connected, and the anode area of ​​the core package 1 is exposed at the open edge of the cathode metal tube shell 3, and the outer surface, open edge and inner surface area near the open edge of the cathode metal tube shell 3 are covered with an insulating coating.

[0049] S4. Apply insulating sealant to the outer surface of the first cathode tube 32 of the cathode metal tube shell 3, and fit the externally installed anode metal tube shell 2 that matches the cathode metal tube shell 3 with the cathode metal tube shell 3 to form an airtight connection. At the same time, fill conductive silver paste between the anode area of ​​the core package 1 and the anode metal tube shell 2 to form an electrical connection between the anode area of ​​the core package 1 and the anode metal tube shell 2, and obtain the first capacitor semi-finished product. The outer surface and the open edge surface of the anode metal tube shell 2 are covered with an insulating coating.

[0050] S5. Wrap an annular coating layer 4 around the outer surface of the first capacitor semi-finished product, and expose the anode end 21 and the cathode end 31 to form the second capacitor semi-finished product.

[0051] S6. Remove the insulating coating from the surfaces of the anode end 21 and cathode end 31 of the second capacitor semi-finished product, and then form a tin layer on the surfaces of the anode end 21 and cathode end 31 to make a capacitor. The tin layer can be formed by chemical plating or electroplating.

[0052] In this embodiment, when the capacitor also includes an "U"-shaped pin 5, step S6 can also be: removing the insulating coating on the surface of the anode end 21 and cathode end 31 of the second capacitor semi-finished product. The removal method can be grinding or sandblasting. Then, a "U"-shaped pin 5 (the pin material is copper and copper alloy) is welded on the surface of the anode end 21 and the cathode end 31 respectively. The two pins are arranged opposite each other and covered with an annular coating layer 4 near the anode end 21 and the cathode end 31. Finally, a tin layer is formed on the outer surface of the pin 5 to make a capacitor.

[0053] It can be known from the above description that the core idea of the present invention is: N capacitor element anode parts and N+1 metal spacers are alternately stacked, welded and fixed, and the cathode parts of the elements are bonded and fixed by conductive silver adhesive to form an element package; the anode part and the cathode part of the element package are electrically connected to an external anode metal sleeve and an external cathode metal sleeve through conductive adhesives respectively, leading out the anode and the cathode; an insulating coating is provided on the outer surface and the open edge surface of the anode metal sleeve, and on the outer surface, the open edge and the inner surface close to the open edge of the cathode metal sleeve, so that the anode metal sleeve and the cathode metal sleeve are electrically non-conductive when sleeved together, preventing short circuit; the capacitor structure of the present invention integrates the functions of the capacitor housing and the lead-out components, and by filling the joint of the anode sleeve and the cathode sleeve with insulating sealant, and combining the coverage of the joint by the annular insulating coating, the hermetic packaging is further ensured. In the present invention, the function of the external terminal can be directly realized by exposing the metal base material at the ends of the two-pole sleeves, and then tin plating is performed to meet the requirement of welding; furthermore, a "匚"-shaped pin can be added on the end surface to increase the area of the pin and improve the welding firmness.

[0054] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inner", "front", "center", "two ends" and other terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, which are only for facilitating the description of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0055] In the present invention, unless otherwise explicitly specified and defined, terms such as "installation", "arrangement", "connection", "fixation", "screwed connection" should be interpreted in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integrated structure; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, or it may be an internal communication between two elements or an interaction relationship between two elements. Unless otherwise explicitly specified, those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0056] Although the embodiments of the present invention have been shown and described, for those skilled in the art, it can be understood that these embodiments can be modified without departing from the principle and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal encapsulated stacked solid electrolytic aluminum electrolytic capacitor characterized by: The device includes a core package (1), an anode metal tube shell (2), a cathode metal tube shell (3), and an annular coating layer (4). The anode metal tube shell (2) and the cathode metal tube shell (3) are both square open structures. The two openings of the anode metal tube shell (2) and the cathode metal tube shell (3) are nested together and airtightly connected to form an outer shell. The ends of the anode metal tube shell (2) and the cathode metal tube shell (3) that are far apart from each other are the anode end (21) and the cathode end (31), respectively. The core package (1) is installed inside the outer shell. The anode area of ​​the core package (1) is electrically connected to the anode end (21), and the cathode area of ​​the core package (1) is electrically connected to the cathode end (31). The annular coating layer (4) is disposed on the outer surface of the outer shell.

2. A metal encapsulated stacked solid electrolytic aluminum electrolytic capacitor according to claim 1, wherein: The annular coating layer (4) is made of a polymer insulating material.

3. A metal encapsulated stacked solid electrolytic aluminum electrolytic capacitor according to claim 1, wherein: The core package (1) includes N cores (11) and N+1 metal pads (12) stacked alternately in sequence. The core (11) includes an anode part (111), a cathode part (112) and a barrier adhesive (113). The metal pads (12) are fixedly connected to the anode part (111) of the core (11) and electrically connected to form the anode region of the core package (1). The cathode parts (112) of each core (11) are fixedly connected to each other and electrically connected to form the cathode region of the core package (1).

4. A metal encapsulated stacked solid electrolytic aluminum capacitor according to claim 3, wherein: The anode portion (111) of the core (11) is fixed to the metal pad (12) by welding, and the cathode portions (112) of each core (11) are fixed to each other by conductive silver paste.

5. A metal-encased stacked solid electrolytic aluminum electrolytic capacitor according to claim 1, wherein: The anode metal shell (2) includes an anode tube (22) with an open end, and the other end of the anode tube (22) is the anode end (21). The cathode metal shell (3) includes a first cathode tube (32) and a second cathode tube (33) connected to each other. The cross-section of the first cathode tube (32) is smaller than the cross-section of the second cathode tube (33). The end of the first cathode tube (32) is open, and the end of the second cathode tube (33) is the cathode end (31). When the anode metal shell (2) and the cathode metal shell (3) are fitted together, the first cathode tube (32) is inserted into the anode tube (22), and the end of the anode tube (22) abuts against the end of the second cathode tube (33).

6. A metal-encapsulated multilayer solid aluminum electrolytic capacitor according to claim 5, characterized in that: The outer surface and open edge of the anode tube (22) are covered with an insulating coating. The outer surface of the first cathode tube (32) and the second cathode tube (33), the open portion of the first cathode tube (32), and the inner surface area of ​​the first cathode tube (32) near the open edge are covered with an insulating coating.

7. A metal-encapsulated multilayer solid aluminum electrolytic capacitor according to claim 1 or 5, characterized in that: The outer surfaces of the anode end (21) and the cathode end (31) are provided with a tin layer.

8. A metal-encapsulated multilayer solid aluminum electrolytic capacitor according to claim 1, characterized in that: The capacitor further comprises two symmetrically arranged leads (5), and the cross-sectional shape of each lead (5) is a "匚" shape. The two leads (5) are respectively closely attached to the outer surfaces of the anode end (21) and the cathode end (31), cover a partial region of the annular coating layer (4) adjacent to the anode end (21) and the cathode end (31), are respectively electrically connected to the anode end (21) and the cathode end (31), and a tin layer is arranged on the outer surface of each of the two leads (5).

9. A method for preparing a metal-encapsulated multilayer solid aluminum electrolytic capacitor according to any one of claims 1-8, characterized in that: Comprising the following steps: S1: Stamping and cutting formed aluminum foil into a rectangle, coating barrier glue (113) to form an anode part (111) and a core cathode region, then sequentially forming a conductive polymer layer, a conductive carbon paste layer and a conductive silver paste layer on the surface of the core cathode region to prepare a cathode part (112), thereby obtaining a core 1; S2: Alternately arranging the anode parts (111) of N cores (11) and N+1 rectangular metal gaskets (12), then realizing the fixed connection between the anode parts (111) and the metal gaskets (12) and the electrical connection between the anode parts (111) by welding, and realizing the fixed connection and electrical connection between the cathode parts (112) of the N cores (11) by bonding and curing through conductive silver adhesive, thereby obtaining a core package (1); S3: Bonding the cathode region of the core package (1) into an external cathode metal shell (3) through conductive silver adhesive, enabling the cathode region of the core package (1) to form electrical connection with the cathode metal shell (3), making the anode region of the core package (1) expose the open edge of the cathode metal shell (3), wherein an insulating coating covers the outer surface, the open edge and the inner surface region adjacent to the open edge of the cathode metal shell (3); S4: Coating an insulating sealant on the outer surface of the first cathode tube body (32) of the cathode metal shell (3), sleeving and combining an external anode metal shell (2) matched with the cathode metal shell (3) with the cathode metal shell (3) to form airtight connection, filling conductive silver adhesive between the anode region of the core package (1) and the anode metal shell (2) at the same time, enabling the anode region of the core package (1) to form electrical connection with the anode metal shell (2), so as to prepare a first semi-finished capacitor, wherein an insulating coating covers the outer surface and the open edge surface of the anode metal shell (2); S5: Wrapping the annular coating layer (4) around the outer peripheral surface of the first semi-finished capacitor, and exposing the anode end (21) and the cathode end (31) to prepare a second semi-finished capacitor; S6: Removing the insulating coating on the surfaces of the anode end (21) and the cathode end (31) of the second semi-finished capacitor, and then forming a tin layer on the surfaces of the anode end (21) and the cathode end (31) to prepare the capacitor.

10. The method for preparing a metal-encapsulated multilayer solid aluminum electrolytic capacitor according to claim 8, characterized in that: The step S6 may further be: removing the insulating coatings on the surfaces of the anode end (21) and the cathode end (31) of the semi-finished second capacitor, then respectively welding a C-shaped lead (5) on the surfaces of the anode end (21) and the cathode end (31), arranging the two leads oppositely, covering a partial area of the annular coating film layer (4) close to the anode end (21) and the cathode end (31), and finally forming a tin layer on the outer surface of the lead (5) to obtain the capacitor.

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