Low-ESR laminated aluminum electrolytic capacitor based on continuous phase metal layer

Abstract

The utility model relates to a low-ESR laminated aluminum electrolytic capacitor based on a continuous phase metal layer. The low-ESR laminated aluminum electrolytic capacitor is characterized by comprising a shell and a core, the core is formed by correspondingly stacking a plurality of layers of pole pieces, the core is packaged in the shell, and an anode leading-out terminal and a cathode leading-out terminal which are connected with a cathode and an anode of the core are respectively arranged at two opposite ends of the shell; the pole piece takes a valve metal foil as a substrate; the periphery of the valve metal foil is divided into an anode part and a cathode part by insulating glue; the peripheral surface of the cathode part is sequentially coated with a solid conductive polymer layer, a non-metal conductive paste layer and a metal conductive paste layer from inside to outside; and the outer surface of the metal conductive paste layer is also coated with a continuous phase conductive metal layer. The negative electrode is coated with the continuous-phase conductive metal layer, so that the cavity defect of the metal slurry layer is improved, the edge coverage rate of conductive metal at the tail part and the side part of the pole piece is increased, the contact area between the pole pieces is increased, the parallel connection effect of the pole pieces is improved, the leading-out distance of the negative electrode is shortened, and the laminated electrolytic capacitor has relatively low ESR (Equivalent Series Resistance) and relatively low leakage current.

Description

Technical Field

[0001] The utility model relates to the technical field of aluminum electrolytic capacitors, in particular to a low ESR laminated aluminum electrolytic capacitor based on a continuous phase metal layer. Background Art

[0002] The mature industrial manufacturing process for stacked aluminum electrolytic capacitors involves separating the anode and cathode regions of cut electroformed foil with 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 surface of the foil to form the capacitor core. Multiple electrodes are stacked on an external lead frame to form a capacitor core package, where the anode and cathode are connected. The capacitor core package is then encapsulated with resin, aged, and pinned to produce the stacked aluminum electrolytic capacitor. Existing stacked aluminum electrolytic capacitors utilize a graphite layer and a silver paste layer to prevent the collector metal (primarily silver) from diffusing through the cathode into the dielectric, thereby maintaining the insulating properties of the alumina dielectric. The interfacial bonding and adhesion between the solid conductive polymer layer, the conductive carbon paste layer, the conductive silver paste layer, and the conductive adhesive in the cathode electrode during thermomechanical stress affect the stability of the capacitor's equivalent series resistance (ESR). However, the epoxy resin in the silver paste layer of the negative electrode of existing laminated aluminum electrolytic capacitors has poor conductivity and the metal particles are widely spaced, resulting in the silver paste layer's conductivity being far lower than that of a pure metal layer. Furthermore, due to the high surface tension of the epoxy resin in the silver paste layer and the shrinkage effect during curing, the silver paste has poor edge coverage on the sides and tail of a single electrode, which in turn affects the parallel connection of multiple electrodes when the electrodes are stacked. Laminated electrolytic capacitors are subject to various thermomechanical stresses during assembly and reflow. Due to the mismatch in the coefficient of thermal expansion (CTE) between the interfaces of the solid conductive polymer layer, the conductive carbon paste layer, the conductive silver paste layer, and the conductive adhesive, high temperatures can generate stress in the interfaces, weakening the mechanical properties of the interfaces and causing delamination. The physical separation between the interfaces also increases the resistance between the interfaces, leading to an increase in the ESR of the finished capacitor. Furthermore, this weakened interfacial bonding stress also leads to higher ESR variations in high humidity environments. These combined effects increase the ESR of laminated electrolytic capacitors, limiting the capacitor's operating frequency. Therefore, a metal layer with good continuity, good conductivity, good mechanical stress, high edge coverage and strong adhesion is needed to improve the ESR, loss and leakage current and service life of the stacked electrolytic capacitor. Utility Model Content

[0003] Based on this, it is necessary to provide a low-ESR laminated aluminum electrolytic capacitor based on a continuous phase metal layer. By covering the negative electrode with the continuous phase conductive metal layer, the void defects in the metal paste layer can be improved, the conductive metal edge coverage of the tail and side of the electrode piece can be increased, the contact area between the electrode pieces can be increased, the parallel effect of the electrode pieces can be improved, the energy loss of the charge can be reduced, and the equivalent series resistance can be reduced. This enables the laminated electrolytic capacitor to have a low ESR and low leakage current. This solves the problems of high ESR and leakage current in laminated aluminum electrolytic capacitors in the prior art.

[0004] The utility model solves the technical problem by adopting the following technical solutions:

[0005] A low-ESR laminated aluminum electrolytic capacitor based on a continuous phase metal layer, characterized by comprising a housing and a core; the core being composed of a plurality of stacked electrode layers, the core being encapsulated within the housing, and having an anode lead terminal and a cathode lead terminal connected to the cathode and anode of the core, respectively, at opposite ends of the housing;

[0006] The electrode is based on a valve metal foil; the outer periphery of the valve metal foil is divided into an anode portion and a cathode portion by an insulating adhesive; the outer periphery of the cathode portion is coated with a solid conductive polymer layer, a non-metallic conductive paste layer, and a metal conductive paste layer in sequence from the inside to the outside; the outer surface of the metal conductive paste layer is also coated with a continuous phase conductive metal layer;

[0007] The continuous phase conductive metal layers between adjacent pole pieces in the core are in contact with each other and form an electrical connection; all the continuous phase conductive metal layers are electrically connected to the cathode lead-out terminal in parallel to serve as negative lead-outs; all the anode parts are in contact with the anode lead-out terminal in parallel to form an electrical connection to serve as anode lead-outs.

[0008] Preferably, the continuous phase conductive metal layer is composed of end faces at the upper and lower ends and side wall faces on all sides that are connected to each other; the inner surface of the continuous phase conductive metal layer is in close contact with the outer surface of the metal conductive paste layer; after the pole pieces are stacked, the corresponding end faces on the adjacent sides of the continuous phase conductive metal layer are in contact with each other and form an electrical connection.

[0009] Preferably, the anode lead terminal includes an anode lead frame, an anode bent portion, and an anode terminal portion; wherein the anode lead frame is connected to the anode portion of the electrode piece, one end of the anode lead frame passes through the outer shell, and the protruding portion is bent along the side surface of the end portion of the outer shell to form the anode bent portion; the anode bent portion is bent along the bottom surface of the outer shell to obtain the anode terminal portion covering the bottom surface of the outer shell portion.

[0010] Preferably, the cathode lead terminal includes a cathode lead frame, a cathode bent portion, and a cathode terminal portion; wherein the upper and lower surfaces of the cathode lead frame are electrically connected to the end face of the continuous phase conductive metal layer, one end of the cathode lead frame passes through the outer shell, and the protruding portion is bent along the side surface of the end portion of the outer shell to form a cathode bent portion; the cathode bent portion is bent along the bottom surface of the outer shell to obtain a cathode terminal portion covering the bottom surface of the outer shell.

[0011] Preferably, the area of ​​the continuous phase conductive metal layer covering the metal conductive paste layer is 5%-95% of the cathode portion; and the thickness of the continuous phase conductive metal layer is 0.1 μm-500 μm.

[0012] Preferably, the valve metal foil is selected from one of aluminum foil, tantalum foil and ceramic sheet, and an oxide medium with unidirectional conductivity is formed on the surface.

[0013] Preferably, the continuous phase conductive metal layer is selected from the group consisting of silver layer, copper layer, nickel layer, tin layer, platinum layer, gold layer, molybdenum layer, ruthenium layer, tungsten layer and alloy layers thereof, or a combination of several metals.

[0014] Preferably, the non-metallic conductive paste layer is selected from one or a mixture of graphite, graphene, carbon and acetylene black; the metal conductive paste layer is selected from at least one or a mixture of copper, silver, silver-coated copper, gold, tin, aluminum, nickel, zinc and platinum.

[0015] Preferably, the continuous phase conductive metal layer is formed by one or a combination of electrochemical deposition, chemical liquid deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, physical sputtering, and spraying.

[0016] The advantages and positive effects of this utility model are as follows: This utility model is a low-ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer, which is used to solve the problems of high ESR and leakage current of multilayer aluminum electrolytic capacitors in the prior art. Compared with the prior art, this utility model has the following advantages:

[0017] This utility model provides a continuous phase conductive metal layer with higher density, higher edge coverage, and stronger mechanical stability for a stacked electrolytic capacitor. This continuous phase conductive metal layer can provide a lower ESR in the stacked electrolytic capacitor. The dense and continuous metal layer used in the stacked electrolytic capacitor can improve void defects in the metal slurry layer, increase the conductive metal edge coverage of the tail and side of the pole piece, increase the contact area between the pole pieces, and enhance the parallel effect of the pole pieces. The parallel connection of the continuous phase conductive metal layer shortens the lead-out distance of the negative electrode, reduces charge energy loss, and lowers the equivalent series resistance, resulting in a lower ESR and lower leakage current for the stacked electrolytic capacitor. This improves its safety and stability, and extends its service life. Furthermore, the manufacturing process is simple, the operation is convenient, and the cost is low, meeting the needs of the production field. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 It is a schematic diagram of the cross-sectional structure of the multilayer aluminum electrolytic capacitor of the utility model.

[0020] Figure 2 It is a schematic diagram of the three-dimensional structure of the laminated aluminum electrolytic capacitor of the utility model.

[0021] Figure 3 It is a schematic diagram of the three-dimensional structure of the pole piece of the utility model.

[0022] Figure 4 It is a schematic diagram of the cross-sectional structure of the pole piece of the utility model.

[0023] Figure 5 It is a three-dimensional schematic diagram of the core of the utility model.

[0024] Figure 6 It is a schematic diagram of the cross-sectional structure of the core of the utility model.

[0025] Explanation of the accompanying symbols: 1. Shell; 2. Core; 3. Pole piece; 4. Anode lead terminal; 5. Cathode lead terminal; 6. Conductor; 301. Aluminum foil; 302. Anode part; 303. Cathode part; 304. Insulating glue; 305. Continuous phase conductive metal layer; 401. Anode lead frame; 402. Anode bent part 402; Anode terminal part 403; 501. Cathode lead frame; 502. Cathode bent part; 503. Cathode terminal part; 3031. Solid conductive polymer layer; 3032. Non-metallic conductive paste layer; 3033. Metal conductive paste layer; 3051. End face; 3052. Side wall surface. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are further described in detail with reference to the accompanying drawings: The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0027] like Figure 1-6 As shown, a low-ESR laminated aluminum electrolytic capacitor based on a continuous phase metal layer is characterized by comprising a housing 1 and a core 2; the core 2 is composed of a plurality of stacked pole pieces 3, the core 2 being encapsulated within the housing 1, and the housing 1 having an anode lead terminal 4 and a cathode lead terminal 5 connected to the cathode and anode of the core 2 at opposite ends thereof, respectively; the pole piece 3 is based on a valve metal foil 301; the outer periphery of the valve metal foil 301 is divided into an anode portion 302 and a cathode portion 303 by an insulating adhesive 304; the outer periphery of the cathode portion 303 is formed from the inside outward according to the invention; It is secondarily coated with a solid conductive polymer layer 3031, a non-metallic conductive paste layer 3032, and a metal conductive paste layer 3033; the outer surface of the metal conductive paste layer 3033 is also coated with a continuous phase conductive metal layer 305; the continuous phase conductive metal layers 305 between adjacent pole pieces 3 in the core 2 are in contact with each other and form an electrical connection; all continuous phase conductive metal layers 305 are connected in parallel and electrically connected to the cathode lead terminal 5 as a negative lead; all anode parts 302 are connected in parallel and in contact with the anode lead terminal 4 and form an electrical connection as an anode lead.

[0028] Specifically, the core 2 of the stacked electrolytic capacitor is composed of several stacked layers of electrode sheets 3. Each core 2 layer provides a base for at least one valve metal foil 301 that can form an oxide film. The negative electrode is coated with a unidirectionally conductive oxide film dielectric on the periphery of the valve metal foil 301. Typically, the stacked core 2 has a rectangular appearance. In this embodiment, the number of stacked electrode sheets 3 layers in the core 2 is not limited, and the number of stacked electrode sheets 3 layers is determined based on the thickness and capacity of the stacked electrolytic capacitor.

[0029] The valve metal foil 301 is selected from one of aluminum foil, tantalum foil, and ceramic sheet, and has a unidirectionally conductive oxide dielectric formed on its surface. Preferably, it is aluminum foil and has an aluminum oxide dielectric formed thereon. The material of the valve metal foil 301 used in the electrode 3 is selected based on the characteristics and dielectric constant of the capacitor. The valve metal foil 301 in the electrode 3 of the laminated aluminum electrolytic capacitor uses aluminum foil as a substrate. An oxide film layer is formed on the surface of the aluminum foil substrate through etching and chemical formation processes. The cut aluminum foil substrate is divided into an anode portion 302 and a cathode portion 303 using a barrier insulating material.

[0030] A solid conductive polymer layer 3031 is formed on the outer surface of the oxide film and in the pores on the surface. This layer can repair defects in the oxide film. The solid conductive polymer layer 3031 is selected from at least one of polypyrrole and its derivatives, polythiophene and its derivatives, and polyaniline and its derivatives. Preferably, it is at least one of polypyrrole, poly-3,4-dioxyethylthiophene, and polyaniline, or a combination of several of these. The solid electrolyte not only improves the stability and high-temperature resistance of the capacitor, but also significantly reduces the equivalent series resistance (ESR), enabling the capacitor to perform better in high-frequency circuits.

[0031] A non-metallic conductive paste layer 3032 is formed on the outer surface of the solid conductive polymer layer 3031. Specifically, the non-metallic conductive paste layer 3032 is selected from one or a mixture of graphite, graphene, carbon and acetylene black, and preferably contains graphite.

[0032] Non-metallic conductive paste layer 3032, such as graphite, has excellent electrical conductivity and a high surface area, making it an ideal charge storage material in multilayer capacitors. When voltage is applied to the capacitor, charge accumulates on the graphite surface, resulting in high capacitance and energy density. Graphite exhibits a porous structure that facilitates the storage and release of charge, further enhancing the performance of the capacitor. Graphite's lattice structure, formed by layers of carbon atoms connected by strong bonds, offers excellent electrical conductivity. This conductivity enables the graphite layers to efficiently transfer electrons, ensuring smooth flow of current within the capacitor.

[0033] By combining graphite with one or more other materials, such as graphene, carbon and acetylene black, metal oxides, and carbon nanotubes, the capacitance performance of capacitors can be significantly improved. The application of such composite materials enables capacitors to have higher specific surface area and lower internal resistance, thereby improving capacitance density and cycle stability.

[0034] The metal conductive paste layer 3033 is selected from at least one of copper, silver, silver-coated copper, gold, tin, aluminum, nickel, zinc, and platinum, or a mixture of several thereof.

[0035] Specifically, the metal conductive paste layer 3033 is formed by mixing metal nanoparticles and resin paste and then curing them. The metal particles are selected from at least one of silver nanoparticles, copper nanoparticles, gold nanoparticles, tin nanoparticles, zinc nanoparticles, platinum nanoparticles and silver-coated copper nanoparticles, and are preferably selected from silver nanoparticles.

[0036] The conductive metal paste layer 3033, such as silver paste, has excellent electrical conductivity and effectively provides a conductive connection for the multilayer capacitor, ensuring smooth current flow between the three layers of the capacitor's internal electrodes. This is crucial for the capacitor's performance stability. The conductive metal paste layer 3033 firmly adheres to the three layers of the capacitor's electrodes, forming a stable conductive path. This adhesion not only helps maintain the structural integrity of the capacitor but also prevents interface separation or conductive connection failure caused by factors such as vibration and temperature fluctuations during long-term use.

[0037] The outer surface of the cathode portion 303 is sequentially coated with a solid conductive polymer layer 3031 , a non-metallic conductive paste layer 3032 , and a metal conductive paste layer 3033 from the inside out; in addition, the outer surface of the metal conductive paste layer 3033 is also coated with a continuous phase conductive metal layer 305 .

[0038] Specifically, the area covered by the continuous conductive metal layer 305 on the metal conductive paste layer 3033 is 5%-95% of the cathode portion 303; the thickness of the continuous conductive metal layer 305 is 0.1 μm-500 μm, preferably 1-30 μm.

[0039] The area covered by the continuous conductive metal layer 305 on the metal conductive paste layer 3033 is 5%-95% of the cathode portion 303. Preferably, the area covered by the continuous conductive metal layer 305 on the metal conductive paste layer 3033 is 5-80% of the cathode portion. When the coverage area is 5% of the cathode portion 303, the cathode portions 303 of the electrode pieces 3 have the conditions for a parallel effect. As the coverage area gradually increases, the contact area between the cathode portions 303 of the electrode pieces 3 also gradually increases, and the parallel effect gradually improves.

[0040] The thickness of the metal conductive paste layer 3033 near the anode part 302 in the electrode 3 is thinner than the tail end of the electrode 3. When the area covered by the continuous phase conductive metal layer 305 on the metal conductive paste layer 3033 is preferably 5-80% of the cathode part, the continuous phase conductive metal layer 305 can be prevented from penetrating into and contacting the solid conductive polymer layer 3031 or the non-metallic conductive paste layer 3032, which may easily cause short circuit or LG increase when the electric field is large.

[0041] The continuous conductive metal layer 305 is composed of interconnected end surfaces 3051 at its upper and lower ends and surrounding sidewall surfaces 3052. The continuous conductive metal layer 305 covers and seals the metal conductive paste layer 3033. The inner surface of the continuous conductive metal layer 305 is in close contact with the outer surface of the metal conductive paste layer 3033. This increases the contact area and ensures a more complete and dense contact with the cathode portion 303.

[0042] In some embodiments, after the pole pieces 3 are stacked, the end surfaces 3051 corresponding to the two adjacent sides of the continuous phase conductive metal layer 305 contact each other and form an electrical connection.

[0043] Specifically, the upper and lower end surfaces 3051 of the pole piece 3 are smooth horizontal surfaces. When the pole pieces 3 are stacked, the end surfaces 3051 corresponding to the adjacent two sides contact each other, which improves the fit and increases the contact area between each other. In some embodiments, a conductive silver paste is also coated between the two bonded end surfaces 3051 of adjacent pole pieces 3, wherein the conductive silver paste fully fills the gap between the end surfaces 3051 of the adjacent continuous phase conductive metal layers 305, further increasing the contact area between the continuous phase conductive metal layers 305 and improving the conductivity. The continuous phase conductive metal layer 305 has a dense and continuous metal layer, which improves the void defects of the metal paste layer, increases the conductive metal edge coverage rate of the tail and side of the pole piece 3, increases the contact area between the pole pieces 3, improves the parallel effect of the pole pieces, and shortens the lead-out distance of the negative electrode.

[0044] The continuous phase conductive metal layer 305 is electrically connected to the cathode lead terminal 5 to serve as a negative lead; the anode portion 302 is in contact with the anode lead terminal 4 and forms an electrical connection to serve as an anode lead.

[0045] After the electrode pieces 3 are stacked, the gaps between the cathode portions 303 of adjacent electrode pieces 3 are filled with conductive paste, ensuring a more complete contact area between the cathode portions 303 of each layer of electrode pieces 3. The cathode portions 303 of the stacked electrode pieces 3 are connected to both the conductive paste and the continuous conductive metal layer 305, further enhancing conductivity. The anode portions 302 of the parallel-connected electrode pieces 3 are connected to the outside via the anode lead terminal 4; the cathode portions 303 of the stacked electrode pieces 3 are connected to the outside via the parallel-connected continuous conductive metal layer 305 and the cathode lead terminal 5.

[0046] The laminated pole pieces 3 are cured to obtain a core 2, which is then sealed with an insulating resin to prepare a shell 1. The core 2 is sealed in the insulating resin shell 1, with the anode lead terminal 4 and the cathode lead terminal 5 extending out of the shell 1. The anode lead terminal 4 and the cathode lead terminal 5 are bent to obtain a laminated aluminum electrolytic capacitor.

[0047] Specifically, the anode lead terminal 4 includes an anode lead frame 401, an anode bent portion 402, and an anode terminal portion 403. The anode lead frame 401 is connected to the anode portion 302 of the electrode piece 3. One end of the anode lead frame 401 extends through the housing 1, and the extended portion is bent along the side of the end of the housing 1 to form the anode bent portion 402. The anode bent portion 402 is bent along the bottom surface of the housing 1 to form the anode terminal portion 103 that covers a portion of the bottom surface of the housing 1. The area and shape of the anode terminal portion 403 covering the bottom surface of the housing 1 are not limited. The cathode lead terminal 5 includes a cathode lead frame 501, a cathode bent portion 502, and a cathode terminal portion 503. The upper and lower surfaces of the cathode lead frame 501 are electrically connected to the end surface 3051 of the continuous phase conductive metal layer 305. One end of the cathode lead frame 501 extends through the housing 1, and the extended portion is bent along the side surface of the end of the housing 1 to form the cathode bent portion 502. The cathode bent portion 502 is bent along the bottom surface of the housing 1 to form the cathode terminal portion 503, which covers a portion of the bottom surface of the housing 1. The area and shape of the cathode terminal portion 503 covering the bottom surface of the housing 1 are not limited. The anode terminal portion 103 and the cathode terminal portion 503 are separated from each other.

[0048] A method for preparing a low ESR laminated aluminum electrolytic capacitor based on a continuous phase metal layer comprises the following steps:

[0049] Step S1: using insulating glue 304 to divide the valve metal foil into an anode portion 302 and a cathode portion 303, and chemically forming the cathode portion 303 of the valve metal foil to form a metal core including a metal oxide film dielectric having unidirectional conductivity;

[0050] Step S2: preparing a solid conductive polymer layer 3031 on the cathode portion 303 of the valve metal foil;

[0051] Step S3: forming a non-metallic conductive paste layer 3032 on the solid conductive polymer layer 3031 of the cathode portion 303;

[0052] Step S4: forming a metal conductive paste layer 3033 on the non-metal conductive paste layer 3032 of the cathode portion 303;

[0053] Step S5: Covering the metal conductive paste layer 3033 of the cathode portion 303 with another layer of continuous phase conductive metal layer 305 to form a single-layer capacitor electrode 3 having an anode and a cathode;

[0054] Step S6: stacking the pole pieces 3 in sequence according to the preset number of layers, connecting and fixing the anode portion 302 to the anode lead terminal 4 by resistance welding or laser welding; and fixing the cathode portion 303 to the cathode lead terminal 5 by bonding and curing the continuous phase conductive metal layer 305 with the cathode lead terminal 5 by means of conductive material, thereby obtaining a laminated structure of a single-layer or multi-layer core 2;

[0055] Step S7: The core 2 is plastic-sealed with insulating resin and aged to form a mold. Except for part of the anode and part of the cathode lead terminals, all structures of the core 2 are covered with insulating resin. At the same time, the anode lead terminal 4 and the cathode lead terminal 5 are bent and led out to obtain a low equivalent resistance laminated electrolytic capacitor containing a continuous phase metal layer.

[0056] The continuous phase conductive metal layer 305 is formed by one or more of the following methods: electrochemical deposition, chemical liquid deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, physical sputtering, and spraying. Example 1

[0057] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of copper.

[0058] Step S1: using insulating glue 304 to divide the aluminum foil into an anode portion 302 and a cathode portion 303, and chemically forming the cathode portion 303 of the aluminum foil to form an aluminum foil containing a metal oxide film dielectric having unidirectional conductivity;

[0059] Step S2: The aluminum foil of the cathode portion 303 is immersed in an electrolyte of 3,4-dioxyethylthiophene and connected to the positive electrode of a power supply to generate an oxidation reaction, thereby preparing a poly 3,4-dioxyethylthiophene layer as the solid conductive polymer layer 3031 by electrochemical polymerization.

[0060] Step S3: The solid conductive polymer layer 3031 of the cathode portion 303 is immersed in graphite slurry, and then dried and cured at 120° C. for 1 hour to prepare a graphite slurry layer as the non-metallic conductive slurry layer 3032 .

[0061] Step S4: The non-metallic conductive paste layer 3032 of the cathode portion 303 is immersed in silver paste, and then dried and cured at 180° C. for 1 hour to prepare a silver conductive paste layer 3033 .

[0062] Step S5: The aluminum foil of the cathode portion 303 is connected to the negative electrode of the power supply, and the tail end is immersed in the copper electroplating solution. The positive electrode of the power supply is connected to the copper plate. A continuous phase metal copper layer is prepared by electrochemical deposition at the tail end of the surface of the metal conductive paste layer 3033. The coverage area of ​​the continuous phase metal copper layer, i.e., the continuous phase conductive metal layer 305, is 5% of the cathode area. The thickness of the continuous phase metal copper layer is 30 μm. A cross-sectional view of a single-piece electrode 3 is obtained, as shown in FIG. Figure 4 shown.

[0063] Step S6: The anode portions 302 of the three electrode pieces 3 and the anode lead frame 401 are stacked together by resistance welding; the continuous phase conductive metal layer 305 of the cathode portion 303 and the cathode lead frame 501 are stacked together by curing the silver paste, and then dried and cured at 180°C for 30 minutes to prepare a core 2 of an aluminum electrolytic capacitor having a three-layer structure and a continuous phase metal layer, as shown in FIG. Figure 5 shown.

[0064] Step S7: The core 2 of the aluminum electrolytic capacitor having a three-layer structure is encapsulated with an insulating epoxy resin and then aged and formed. All structures inside the capacitor are covered with the insulating resin. The anode lead terminal 4 and the cathode lead terminal 5 are passed through the insulating resin at the rear end. At the same time, the anode lead terminal 4 and the cathode lead terminal 5 are bent and led out to cover the two ends of the shell 1 respectively. A low equivalent series resistance (ESR) multilayer aluminum electrolytic capacitor containing a continuous phase metal layer 305 is obtained, as shown in FIG. Figure 2 shown. Example 2

[0065] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of copper.

[0066] Example 2 differs from Example 1 in that step S5 utilizes chemical liquid deposition to form a continuous copper layer. The continuous copper layer, or continuous conductive metal layer 305, covers 50% of the cathode portion 303 and has a thickness of 15 μm. The resulting electrode 3 is laminated and packaged to produce a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous metal layer 305. Example 3

[0067] In this embodiment, aluminum foil is used as the base, and the continuous phase conductive metal layer 305 is made of silver.

[0068] Example 3 differs from Example 1 in that, in step S5, a continuous-phase metallic silver layer is formed using electrochemical deposition. The continuous-phase metallic silver layer, or continuous-phase conductive metal layer 305, covers 80% of the cathode portion 303 and has a thickness of 500 μm. In step S6, three electrode sheets 3 are stacked to form a core 3. This stacking and packaging process yields a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous-phase metallic layer 305. Example 4

[0069] In this embodiment, aluminum foil is used as the base, and the continuous phase conductive metal layer 305 is made of nickel.

[0070] Example 4 differs from Example 1 in that step S5 utilizes chemical vapor deposition to form a continuous nickel layer. The continuous nickel layer, or continuous conductive metal layer 305, covers 10% of the cathode portion 303 and has a thickness of 20 μm. In step S6, four electrode sheets 3 are stacked to form a core 3. This stacking and packaging process yields a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous metal layer 305. Example 5

[0071] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of tin.

[0072] Example 5 differs from Example 1 in that step S4 involves impregnating the non-metallic conductive paste layer 3032 of the cathode portion 303 with a mixture of gold, tin, aluminum, nickel, zinc, and platinum, followed by drying and curing at 180°C for one hour to produce a silver conductive paste layer 3033. Step S5 involves forming a continuous-phase metallic silver layer using physical vapor deposition. The continuous-phase metallic tin layer, i.e., the continuous-phase conductive metal layer 305, covers 50% of the cathode portion 303 and has a thickness of 10 μm. In step S6, four electrode sheets 3 are stacked to form a core 3. After stacking and packaging, a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous-phase metallic layer 305 is obtained. Example 6

[0073] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of gold.

[0074] Example 6 differs from Example 1 in that, in step S5, a continuous-phase gold layer is formed using chemical liquid deposition. The continuous-phase gold layer, or continuous-phase conductive metal layer 305, covers 70% of the cathode portion 303. The continuous-phase copper layer has a thickness of 5 μm. The resulting electrode 3 is laminated and packaged to produce a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous-phase metal layer 305. Example 7

[0075] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of ruthenium.

[0076] Example 7 differs from Example 1 in that, in step S5, a continuous-phase ruthenium metal layer is formed using a physical sputtering method. The continuous-phase ruthenium metal layer, i.e., the continuous-phase conductive metal layer 305, covers 20% of the cathode portion 303, and the thickness of the continuous-phase copper metal layer is 2 μm. In step S6, six electrode pieces 3 are stacked to form the core 3. After stacking and packaging, a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous-phase metal layer 305 is obtained. Example 8

[0077] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of molybdenum.

[0078] Example 8 differs from Example 1 in that, in step S5, a continuous-phase metallic molybdenum layer is formed using a physical sputtering method. The continuous-phase metallic molybdenum layer, i.e., the continuous-phase conductive metal layer 305, covers 60% of the cathode portion 303 and has a thickness of 1 μm. In step S6, six electrode pieces 3 are stacked to form the core 3. This stacking and packaging process yields a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous-phase metallic layer 305. Example 9

[0079] In this embodiment, aluminum foil is used as the substrate, and the continuous phase conductive metal layer 305 is made of ruthenium.

[0080] Example 9 differs from Example 1 in that, in step S5, a continuous-phase ruthenium layer is formed using physical vapor deposition. The continuous-phase ruthenium layer, or continuous-phase conductive metal layer 305, covers 80% of the cathode portion 303 and has a thickness of 0.1 μm. In step S6, six electrode pieces 3 are stacked to form a core 3. This stacking and packaging process yields a low equivalent series resistance (ESR) laminated aluminum electrolytic capacitor containing the continuous-phase metal layer 305.

[0081] In addition to the above embodiment, in other embodiments, the valve metal foil 301 can also be selected from tantalum foil or ceramic sheet, and a unidirectionally conductive oxide dielectric is formed on its surface. In addition to the above embodiment, the continuous phase conductive metal layer 305 can also be selected from a stack of one or more metals including platinum, molybdenum, tungsten, and alloys thereof. In addition to the above embodiment, the non-metallic conductive paste layer 3032 can also be selected from one or a mixture of graphene, carbon, and acetylene black; and the metal conductive paste layer 3033 can also be selected from at least one of copper, silver-coated copper, gold, tin, aluminum, nickel, zinc, and platinum, or a mixture of several of these.

[0082] Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Comparative Example 1

[0083] Comparative Example 1 uses aluminum foil as the substrate.

[0084] The difference between Comparative Example 1 and Example 1 is that the cathode portion 303 of the pole piece 3 in Comparative Example 1 is not covered with the continuous phase conductive metal layer 305 , and the other steps and processes are the same as those in Example 1. Comparative Example 2

[0085] Comparative Example 2 uses aluminum foil as the substrate.

[0086] The difference between Comparative Example 2 and Example 2 is that the cathode portion 303 of the electrode 3 in Comparative Example 2 is not covered with the continuous phase conductive metal layer 305; four electrode pieces 3 are stacked to prepare the core 3. The other steps and processes are the same as those in Example 3. Comparative Example 3

[0087] Comparative Example 3 uses aluminum foil as the substrate.

[0088] The difference between Comparative Example 3 and Example 3 is that the cathode portion 303 of the pole piece 2 in Comparative Example 3 is not covered with the continuous phase conductive metal layer 305; the core 3 is prepared by stacking six pole pieces 3, and the other steps and processes are the same as those in Example 3.

[0089] The prepared multilayer aluminum capacitors were tested according to the national standards GB / T6346.25-2018 and GB / T 6346.2501-2018 for capacitance, DF, ESR, leakage current, ripple current resistance, durability, and steady-state damp-heat performance. Capacitance was measured using a digital bridge LCR tester at a frequency of 120Hz, and ESR at a frequency of 1kHz; leakage current was measured using a leakage current meter. Durability was tested at a temperature of 105°C and rated voltage, while steady-state damp-heat testing was performed at a temperature of 85°C and a humidity of 85%.

[0090] Table 1 shows a comparison of the performance of the laminated aluminum electrolytic capacitors prepared in Examples 1-9 and Comparative Examples 1-3.

[0091] The performance tests of the laminated aluminum electrolytic capacitors prepared in the above embodiment and the comparative example were compared. The experimental results show that the use of the continuous phase conductive metal layer 305 design results in a lower equivalent series resistance (ESR) value of the laminated aluminum electrolytic capacitor, and other electrical properties are superior to those of the comparative example. This is mainly reflected in the fact that the negative electrode portion 303 of the electrode 3 of the utility model is covered with the continuous phase conductive metal layer 305. The continuous phase conductive metal layer 305 provides metal layer characteristics with higher density, higher edge coverage, and stronger mechanical stability, which improves the void defects of the metal slurry layer, increases the conductive metal edge coverage of the tail and side of the electrode, increases the contact area between the electrode pieces, improves the parallel effect of the electrode pieces, shortens the lead-out distance of the negative electrode, and thus makes the laminated electrolytic capacitor have lower ESR and lower leakage current, improves its safety and stability, and extends the service life of the laminated electrolytic capacitor.

[0092] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the embodiments described in the specific implementation methods. Any other implementation methods derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer, characterized by: The invention comprises a shell (1) and a core (2); the core (2) is composed of a plurality of layers of pole pieces (3) stacked correspondingly, the core (2) is encapsulated inside the shell (1), and opposite ends of the shell (1) are respectively provided with an anode lead terminal (4) and a cathode lead terminal (5) connected to the cathode and anode of the core (2); The electrode (3) is based on a valve metal foil (301); the outer periphery of the valve metal foil (301) is divided into an anode portion (302) and a cathode portion (303) by an insulating glue (304); the outer periphery of the cathode portion (303) is sequentially coated with a solid conductive polymer layer (3031), a non-metallic conductive paste layer (3032), and a metal conductive paste layer (3033) from the inside out; the outer surface of the metal conductive paste layer (3033) is also coated with a continuous phase conductive metal layer (305); The continuous phase conductive metal layers (305) between adjacent pole pieces (3) in the core (2) are in contact with each other and form an electrical connection; all the continuous phase conductive metal layers (305) are connected in parallel to the cathode lead terminal (5) and are electrically connected to serve as negative electrode leads; and all the anode portions (302) are connected in parallel to the anode lead terminal (4) and are electrically connected to serve as anode leads.

2. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The continuous phase conductive metal layer (305) is composed of end surfaces (3051) at the upper and lower ends and side wall surfaces (3052) around the edges, which are connected to each other; the inner surface of the continuous phase conductive metal layer (305) is in close contact with the outer surface of the metal conductive paste layer (3033); after the pole pieces (3) are stacked, the end surfaces (3051) corresponding to the adjacent sides of the continuous phase conductive metal layer (305) are in contact with each other and form an electrical connection.

3. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The anode lead terminal (4) comprises an anode lead frame (401), an anode bent portion (402), and an anode terminal portion (403); wherein the anode lead frame (401) is connected to the anode portion (302) of the pole piece (3); one end of the anode lead frame (401) passes through the shell (1), and the protruding portion is bent along the side surface of the end of the shell (1) to form the anode bent portion (402); the anode bent portion (402) is bent along the bottom surface of the shell (1) to obtain the anode terminal portion (403) covering part of the bottom surface of the shell (1).

4. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The cathode lead terminal (5) comprises a cathode lead frame (501), a cathode bent portion (502), and a cathode terminal portion (503); wherein the upper and lower surfaces of the cathode lead frame (501) are electrically connected to the end surface (3051) of the continuous phase conductive metal layer (305); one end of the cathode lead frame (501) passes through the shell (1), and the protruding portion is bent along the side surface of the end of the shell (1) to form the cathode bent portion (502); the cathode bent portion (502) is bent along the bottom surface of the shell (1) to obtain the cathode terminal portion (503) covering part of the bottom surface of the shell (1).

5. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The area of ​​the continuous phase conductive metal layer (305) covering the metal conductive paste layer (3033) is 5%-95% of the cathode portion (303); and the thickness of the continuous phase conductive metal layer (305) is 0.1 μm-500 μm.

6. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The valve metal foil (301) is selected from one of aluminum foil, tantalum foil, and ceramic sheet, and an oxide medium with unidirectional conductivity is formed on the surface.

7. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The continuous phase conductive metal layer (305) is selected from one of a silver layer, a copper layer, a nickel layer, a tin layer, a platinum layer, a gold layer, a molybdenum layer, a ruthenium layer, a tungsten layer and an alloy layer thereof.

8. The low ESR multilayer aluminum electrolytic capacitor based on a continuous phase metal layer according to claim 1, characterized in that: The non-metallic conductive paste layer (3032) is selected from one of graphite, graphene, carbon and acetylene black, or a mixture of several thereof; the metal conductive paste layer (3033) is selected from one of copper, silver, silver-coated copper, gold, tin, aluminum, nickel, zinc and platinum.

Images