A solid state laminated aluminum electrolytic capacitor having a transition conductive layer and a method of manufacturing the same
By setting a transition layer between the conductive polymer layer and the negative electrode lead-out layer, and using graphene and carbon powder to form a highly efficient conductive network, the problem of high resistance in aluminum multilayer capacitors at high frequencies is solved, thereby reducing the ESR value and improving the ripple resistance performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN AIHUA GROUP CO LTD
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-29
AI Technical Summary
Existing aluminum multilayer capacitors have high resistance at high frequencies, which limits their application in higher frequency fields, and the improvement of high frequency characteristics is limited.
A transition layer is set between the conductive polymer layer and the negative electrode lead-out layer. The transition layer is composed of conductive polymer, carbon powder and graphene nanosheets, with the weight ratio of graphene to carbon powder being 1:20-1:40, forming a highly efficient conductive network.
The interface resistance between the conductive polymer layer and the negative electrode lead-out layer is reduced, and the ESR value is reduced by more than 10% at a frequency of 100kHz, thereby improving the capacitor's ripple resistance and service life.
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Figure CN122117649A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a multilayer aluminum electrolytic capacitor, and more particularly to a solid multilayer aluminum electrolytic capacitor with a composite cathode and a transition conductive layer, and a method for preparing the same. Background Technology
[0002] With the increasing power supply requirements of digital chips such as CPUs and GPUs, stringent requirements have been placed on capacitors for low equivalent series resistance (ESR) and high ripple current tolerance at high frequencies.
[0003] Currently, mainstream aluminum multilayer capacitors mainly adopt the following technical routes: Conductive polymer cathode type, such as patent CN115376830A which uses conductive polymers like PEDOT as the cathode electrolyte. Its advantage is a low ESR, typically from a few milliohms to tens of milliohms, but its disadvantage is limited improvement in high-frequency characteristics. Another approach uses a carbon powder layer and silver paste as the negative electrode lead-out layer; this technology is mature, but the limited conductivity of the carbon powder layer results in higher impedance at high frequencies, limiting its application in higher frequency fields. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a solid multilayer aluminum electrolytic capacitor with a composite cathode and a transition conductive layer and a method for preparing the same.
[0005] To solve the above-mentioned technical problems, the technical solution proposed by the present invention is as follows: a solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer, comprising a core, wherein the core comprises multiple stacked monoliths; each monolith comprises a positive electrode region and a negative electrode region; the positive electrode region comprises an aluminum foil and an oxide film formed on the aluminum foil, the negative electrode region comprises an aluminum foil, an oxide film formed on the aluminum foil, a polymer conductive layer, a transition layer, and a negative electrode lead-out layer, wherein the polymer conductive layer is formed on the surface of the oxide film in the negative electrode region, and the transition layer is disposed between the polymer conductive layer and the negative electrode lead-out layer; the transition layer comprises a polymer conductive layer, carbon powder, and graphene nanosheets, wherein the weight of the graphene nanosheets and carbon powder in the transition layer is 2.5%-10% of the weight of the polymer conductive layer.
[0006] In the aforementioned solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer, preferably, the weight ratio of graphene to carbon powder is 1:20-1:40.
[0007] Preferably, in the above-mentioned solid multilayer aluminum electrolytic capacitor with a transition conductive layer, the transition layer is formed on the surface of a polymer conductive layer, and the negative electrode lead-out layer is disposed on the surface of the transition layer; the negative electrode lead-out layer includes a carbon powder layer and a silver paste layer, wherein the carbon powder layer is formed on the surface of the transition layer, and the silver paste layer is formed on the surface of the carbon powder layer.
[0008] Preferably, in the above-mentioned solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer, 2%-10% of graphene nanosheets are added to the carbon powder layer.
[0009] A method for fabricating a solid multilayer aluminum electrolytic capacitor with a transition conductive layer includes the following steps:
[0010] 1) Cut the aluminum foil;
[0011] 2) Prepare a conductive polymer layer in the negative electrode region;
[0012] 3) A transition layer is formed on the conductive polymer layer; the transition layer includes the conductive polymer, carbon powder and graphene nanosheets, wherein the weight of graphene nanosheets and carbon powder in the transition layer is 2.5%-10% of the weight of the conductive polymer; the weight ratio of graphene to carbon powder is 1:20-1:40.
[0013] 4) A negative electrode lead-out layer is formed on the surface of the transition layer to obtain a monolithic wafer;
[0014] 5) Stack multiple single-layer capacitors together and cure them at high temperature to form a capacitor core; or apply conductive silver paste to the bottom of a single-layer capacitor and cure it at high temperature to form a capacitor core.
[0015] In the above-mentioned method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer, preferably, in step 5), the polymer conductive layer formed in step 4) is immersed in a mixture of polymer conductive layer, carbon powder and graphene nanosheets, then removed and dried, and the process is repeated 2-5 times.
[0016] In the above-mentioned method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer, preferably, in step 5), the polymer conductive layer formed in step 4) is immersed as a working electrode in a mixture of polymer conductive monomer, carbon powder and graphene nanosheets, and electrochemical polymerization is carried out using a constant current method.
[0017] In the above-mentioned method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer, preferably, in step 5), the polymer conductive layer formed in step 4) is immersed in a mixture of polymer conductive monomer, carbon powder and graphene nanosheets, and then dried; then immersed in an oxidizing solvent, and then heated to undergo a polymerization reaction; after cleaning, it is dried.
[0018] In the above-described method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer, preferably, the negative electrode lead-out layer comprises a carbon powder layer and a silver paste layer, wherein the carbon powder layer is formed on the surface of the transition layer and the silver paste layer is formed on the surface of the carbon powder layer.
[0019] In the above-mentioned method for preparing a solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer, preferably, 2%-10% of graphene nanosheets are added to the carbon powder layer.
[0020] Compared with existing technologies, the advantages of this invention are as follows: In this invention, a transition layer is provided between the conductive polymer layer and the negative electrode lead layer, which effectively reduces the interface resistance between the conductive polymer layer and the negative electrode lead layer; this results in an overall conductivity of the composite cathode that is approximately 10%-30% higher than without the transition layer. At a frequency of 100kHz, the ESR value of the solid-state multilayer aluminum electrolytic capacitor with the transition conductive layer of this invention can be reduced by more than 10% compared to conventional products. Simultaneously, due to the reduced ESR, the internal heat generation of the capacitor is significantly reduced when encountering large ripple currents, enabling the product to operate stably in higher temperature environments and extending its service life. Attached Figure Description
[0021] Figure 1 This is a cross-sectional view of the solid multilayer aluminum electrolytic capacitor with a transition conductive layer in Example 1.
[0022] Figure 2 This is a cross-sectional view of a single piece in Example 1.
[0023] Legend
[0024] 1. Outer shell; 2. Single sheet; 21. Aluminum foil; 22. Oxide film; 23. High molecular conductive polymer layer; 24. Transition layer; 25. Negative electrode lead-out layer; 251. Carbon powder layer; 252. Silver paste layer. Detailed Implementation
[0025] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.
[0026] It should be noted that when a component is described as being "fixed to, attached to, connected to or connected to" another component, it can be directly fixed to, attached to, connected to or connected to the other component, or it can be indirectly fixed to, attached to, connected to or connected to the other component through other intermediate connectors.
[0027] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.
[0028] Example 1
[0029] like Figure 1The solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer shown includes a core, which comprises multiple stacked monoliths 2. Each monolith 2 includes a positive electrode region, a negative electrode region, and an insulating adhesive, with the insulating adhesive disposed between the positive and negative electrode regions. The positive electrode region includes an aluminum foil 21 and an oxide film 22 formed on the aluminum foil 21. The negative electrode region includes the aluminum foil 21, the oxide film 22 formed on the aluminum foil 21, a conductive polymer layer 23, a transition layer 24, and a negative electrode lead-out layer 25. The conductive polymer layer 23 is formed on the surface of the oxide film 22 in the negative electrode region, and the transition layer 24 is disposed between the conductive polymer layer 23 and the negative electrode lead-out layer 25. The transition layer 24 includes a conductive polymer, carbon powder, and graphene nanosheets. The weight of the graphene nanosheets and carbon powder in the transition layer 24 is 2.5%-10% of the weight of the conductive polymer. The weight ratio of graphene to carbon powder is 1:20-1:40.
[0030] In this embodiment, the graphene in the transition layer 24, as a two-dimensional highly conductive material, builds a "high-speed conductive bridge" in the polymer matrix, allowing electrons to move at high speed along the graphene sheets. The transition layer 24 is located between the polymer conductive layer 23 and the negative electrode lead-out layer 25, effectively reducing the interface resistance between them. This reduces the ESR value of the product at high frequencies, thereby improving its ripple resistance.
[0031] In this embodiment, graphene forms a highly efficient "surface contact" backbone conductive network in transition layer 24. Carbon powder, as a zero-dimensional / one-dimensional point-like or chain-like conductive filler, fills the spaces between graphene sheets, acting as a "point contact" bridge and filling the gaps in the conductive network. The addition of carbon powder can fill the gaps between graphene networks, forming a three-dimensional conductive network combining "points and surfaces," potentially further reducing the overall resistivity. Simultaneously, carbon powder helps disperse graphene, preventing its agglomeration and making the slurry or composite material more stable. A conductive polymer serves as the matrix, bonding and dispersing the two components.
[0032] In this embodiment, the transition layer 24 is formed on the surface, and the negative electrode lead-out layer 25 is disposed on the surface of the transition layer 24; the negative electrode lead-out layer 25 includes a toner layer 251 and a silver paste layer 252, the toner layer 251 is formed on the surface of the transition layer 24, and the silver paste layer 252 is formed on the surface of the toner layer 251.
[0033] In this embodiment, the conductive polymer and carbon powder in the transition layer 24 enable the transition layer 24 to effectively serve as a transition between the conductive polymer layer 23 and the negative electrode lead-out layer 25, thereby effectively reducing the interface resistance between the conductive polymer layer 23 and the negative electrode lead-out layer 25.
[0034] The method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer in this embodiment includes the following steps:
[0035] 1) Cut aluminum foil 21.
[0036] 2) Apply a separating adhesive to the cut aluminum foil 21 to form a positive electrode area and a negative electrode area on the aluminum foil 21.
[0037] 3) Prepare a conductive polymer layer 23 in the negative electrode region. In this embodiment, the conductive polymer layer 23 can be formed in the negative electrode region by impregnation or coating with a conductive polymer dispersion, or by chemical or electrochemical methods.
[0038] 4) A transition layer 24 is formed on the conductive polymer layer 23; the transition layer 24 includes the conductive polymer, carbon powder and graphene nanosheets, and the weight of graphene nanosheets and carbon powder in the transition layer 24 is 2.5%-10% of the weight of the conductive polymer; the weight ratio of graphene to carbon powder is 1:20-1:40.
[0039] 5) A negative electrode lead-out layer 25 is formed on the surface of the transition layer 24 to obtain a monolith 2.
[0040] 6) Stack multiple single-layer 2 pieces together and cure them at high temperature to form a capacitor core; or apply conductive silver paste to the bottom of single-layer 2 and cure it at high temperature to form a capacitor core.
[0041] 7) Encapsulate the core inside the outer casing 1.
[0042] In this embodiment, there are three ways to form the transition layer 24 on the conductive polymer layer 23 in step 5).
[0043] The first method involves immersing the conductive polymer layer 23 formed in step 4) into a uniform mixture of conductive polymer, carbon powder, and graphene nanosheets, removing it, drying it, and repeating this process 2-5 times.
[0044] The second method involves immersing the conductive polymer layer 23 formed in step 4) as the working electrode into a homogeneous mixture of conductive polymer monomers, carbon powder, and graphene nanosheets, and then performing electrochemical polymerization using a constant current method. The current density is 0.1-0.8 mA / cm². 2 The polymerization process is repeated 4-8 times, each time for 45 seconds, to form a composite layer with a thickness controlled at around 2µm.
[0045] The third method involves immersing the conductive polymer layer 23 formed in step 4) into a uniform mixture of conductive polymer monomers, carbon powder, and graphene nanosheets, then removing it and drying it; then immersing it in an oxidizing solvent, removing it, and heating it until a polymerization reaction occurs; cleaning it, and drying it; repeating this process 2-5 times.
[0046] In this embodiment, the negative electrode lead-out layer 25 includes a carbon powder layer 251 and a silver paste layer 252. The carbon powder layer 251 is formed on the surface of the transition layer 24, and the silver paste layer 252 is formed on the surface of the carbon powder layer 251.
[0047] In this embodiment, a transition layer 24 is provided between the conductive polymer layer 23 and the negative electrode lead layer 25, which effectively reduces the interface resistance between the conductive polymer layer 23 and the negative electrode lead layer 25. This results in an overall conductivity of the composite cathode that is approximately 10%-30% higher than without the transition layer 24. At a frequency of 100kHz, the ESR value of the solid-state multilayer aluminum electrolytic capacitor with the transition conductive layer of this invention is more than 10% lower than that of conventional products. Simultaneously, due to the reduced ESR, the internal heat generation of the capacitor is significantly reduced when encountering large ripple currents, enabling the product to operate stably at higher temperatures and extending its service life.
[0048] Example 2
[0049] In this embodiment, 2%-10% of graphene nanosheets are added to the carbon powder layer 251. The other parts are the same as in Example 1.
Claims
1. A solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer, characterized in that: The device includes a core comprising multiple stacked monoliths; each monolith includes a positive electrode region and a negative electrode region; the positive electrode region includes an aluminum foil and an oxide film formed on the aluminum foil; the negative electrode region includes an aluminum foil, an oxide film formed on the aluminum foil, a conductive polymer layer, a transition layer, and a negative electrode lead-out layer; the conductive polymer layer is formed on the surface of the oxide film in the negative electrode region; the transition layer is disposed between the conductive polymer layer and the negative electrode lead-out layer; the transition layer includes a conductive polymer, carbon powder, and graphene nanosheets, wherein the weight of the graphene nanosheets and carbon powder in the transition layer is 2.5%-10% of the weight of the conductive polymer.
2. The solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 1, characterized in that: The weight ratio of graphene to carbon powder is 1:20 to 1:
40.
3. The solid multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 1, characterized in that: The transition layer is formed on the surface of the conductive polymer layer, and the negative electrode lead-out layer is disposed on the surface of the transition layer; the negative electrode lead-out layer includes a toner layer and a silver paste layer, the toner layer is formed on the surface of the transition layer, and the silver paste layer is formed on the surface of the toner layer.
4. The solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 3, characterized in that: The carbon powder layer contains 2%-10% graphene nanosheets.
5. A method for preparing a solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer, characterized in that, Includes the following steps: 1) Cut the aluminum foil; 2) Prepare a conductive polymer layer in the negative electrode region; 3) A transition layer is formed on the conductive polymer layer; the transition layer includes the conductive polymer, carbon powder and graphene nanosheets, wherein the weight of graphene nanosheets and carbon powder in the transition layer is 2.5%-10% of the weight of the conductive polymer; the weight ratio of graphene to carbon powder is 1:20-1:
40. 4) A negative electrode lead-out layer is formed on the surface of the transition layer to obtain a monolithic wafer; 5) Multiple single-layer capacitors are stacked and cured at high temperature to form a capacitor core; Alternatively, conductive silver paste can be applied to the bottom of a single piece and cured at high temperature to form a capacitor core.
6. The method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 5, characterized in that: In step 5), the conductive polymer layer formed in step 4) is immersed in a mixture of conductive polymer, carbon powder and graphene nanosheets, then removed and dried, and this process is repeated 2-5 times.
7. The method for preparing a solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 5, characterized in that: In step 5), the conductive polymer layer formed in step 4) is used as a working electrode and immersed in a mixture of conductive polymer monomers, carbon powder and graphene nanosheets, and electrochemical polymerization is carried out using a constant current method.
8. The method for preparing a solid-state multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 5, characterized in that: In step 5), the conductive polymer layer formed in step 4) is immersed in a mixture of conductive polymer monomers, carbon powder and graphene nanosheets, then removed and dried; then immersed in an oxidizing solvent, removed and heated until a polymerization reaction occurs; then cleaned and dried.
9. The method for preparing a solid multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 5, characterized in that: The negative electrode lead-out layer includes a carbon powder layer and a silver paste layer, wherein the carbon powder layer is formed on the surface of the transition layer and the silver paste layer is formed on the surface of the carbon powder layer.
10. The solid multilayer aluminum electrolytic capacitor with a transition conductive layer according to claim 9, characterized in that: The carbon powder layer contains 2%-10% graphene nanosheets.