Solid-state capacitor with good sealing effect and preparation method thereof

Abstract

A solid-state capacitor with a good sealing effect comprises a core package and a silicone rubber sealing layer, and the silicone rubber sealing layer is formed on the surface of the core package through a glue dipping process or a glue injection process. The silicon rubber sealing layer completely wraps and seals the core package. According to the solid-state capacitor disclosed by the invention, the core package is sealed by the silicon rubber, so that the sealing effect is good, and the product completely meets the requirements of double-85 experiments; and meanwhile, the requirement of an AEC-Q200 vibration test can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to a solid-state capacitor, in particular to a solid-state capacitor with good sealing effect and a preparation method thereof. BACKGROUND

[0002] Different solid-state capacitors are suitable for the needs of different industries. Among them, thin film capacitors are mainly used in electronic, home appliance, communication, power, electrified railway, hybrid electric vehicle, wind power generation, solar power generation and other industries. The stable development of these industries has promoted the growth of the thin film capacitor market. The stacked solid-state aluminum electrolytic capacitor (MLPC) is a new type of solid-state capacitor, which is mainly used in servers, notebook computers, 5G small base stations, Internet of Things and other fields. Compared with traditional wound capacitors, it adopts a multi-layer structure design and can provide higher capacity in a smaller volume. The characteristics of the stacked solid-state aluminum electrolytic capacitor include lower equivalent series resistance (ESR), good high-frequency characteristics, higher ripple current bearing capacity, and excellent high-temperature performance.

[0003] At present, the packaging of both thin film capacitors and stacked solid-state capacitors uses epoxy resin pouring glue for pouring. The epoxy resin pouring glue is a thermosetting epoxy resin with very small initial viscosity, but the viscosity rises rapidly to solidification as the temperature rises. After the epoxy resin pouring glue is solidified, it has a high-rigidity structure. In the use environment, the temperature changes, vibrations, and especially in the case of ultra-wide temperature use, the epoxy resin pouring glue is prone to cracking, causing abnormal air tightness. As more and more electronic products need to meet the double 85 test (temperature 85℃, relative humidity 85%), thin film capacitors and stacked solid-state aluminum electrolytic capacitors generally have poor sealing properties, and water vapor easily penetrates into the capacitor in a humid environment, causing electrical performance problems. In a vibrating use environment, the part where the pin contacts the epoxy resin is prone to cracking and falling off, causing the capacitor to fail. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a solid-state capacitor with good sealing effect and a preparation method thereof.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows: a solid-state capacitor with good sealing effect, comprising a core package and a silicone rubber sealing layer, the core package is formed with a silicone rubber sealing layer on the surface by a dipping process or a glue injection process; the silicone rubber sealing layer completely wraps and seals the core package.

[0006] The solid-state capacitor with good sealing effect described above, preferably, the viscosity of the silicone rubber forming the silicone rubber sealing layer is 15-55 Pa·s.

[0007] The solid capacitor with good sealing effect, preferably, the silicon rubber of the silicon rubber sealing layer comprises chain-like siloxane oligomers with active end groups of hydroxyl or acetoxy, fillers, cross-linking agents and additives, and the additives comprise catalysts and / or curing agents.

[0008] The solid capacitor with good sealing effect, preferably, the chain-like siloxane oligomers with active end groups of hydroxyl or acetoxy comprise hydroxyl-terminated polydimethylsiloxane.

[0009] The solid capacitor with good sealing effect, preferably, the fillers comprise one or more of white carbon black, calcium carbonate and clay.

[0010] The solid capacitor with good sealing effect, preferably, the catalysts comprise Bu2Sn(OCOC 11 H 23 )2.

[0011] The solid capacitor with good sealing effect, preferably, the curing agents comprise tetraethyl orthosilicate or / and hydroxyl amino silane.

[0012] The solid capacitor with good sealing effect, preferably, the cross-linking agents comprise a mixture of MeSi(OAc)3 and EtSi(OAC)3 at a ratio of 1:1.

[0013] A method for preparing a solid capacitor with good sealing effect, comprising the following steps:

[0014] 1) preparation of silicon rubber;

[0015] 1.1) mixing chain-like siloxane oligomers with active end groups of hydroxyl or acetoxy and fillers uniformly;

[0016] 1.2) adding catalysts and / or curing agents to step 1) and mixing uniformly;

[0017] 1.3) adjusting the viscosity of the mixture of step 2) to 15-55 Pa·s, and waiting for use;

[0018] 2) pouring the silicon rubber prepared in step 1) into a mold;

[0019] 3) immersing the core package into the silicon rubber in the mold, and the silicon rubber completely wraps the core package;

[0020] 4) incubating the silicon rubber and the core package in step 3) at a temperature of 40-60°C for 5-10 min; so that the silicon rubber is cross-linked and cured; and obtaining a finished product of a film capacitor.

[0021] A thin-film capacitor or a multilayer capacitor includes the aforementioned silicone rubber sealing layer and a core package, wherein the silicone rubber sealing layer is formed on the surface of the core package by an impregnation process; the silicone rubber sealing layer completely encapsulates and seals the core package.

[0022] Compared with the prior art, the advantages of the present invention are: the solid capacitor of the present invention has a good sealing effect because its core is sealed with silicone rubber, and the product fully meets the requirements of the double 85 test. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the thin-film capacitor in Example 1.

[0024] Figure 2 This is a schematic diagram of the structure of the multilayer solid aluminum electrolytic capacitor in Example 2.

[0025] Legend

[0026] 1. Silicone rubber sealing layer; 2. Leads; 3. Core package. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Example 1

[0031] like Figure 1 The solid-state capacitor shown is a film capacitor with good sealing performance. It includes a core and a silicone rubber sealing layer 1. The silicone rubber sealing layer 1 is formed on the surface of the core through an impregnation process. The silicone rubber sealing layer 1 completely encapsulates and seals the core, and the leads 2 on the core extend out of the silicone rubber sealing layer. In this embodiment, the viscosity of the silicone rubber forming the silicone rubber sealing layer is 15-25 Pa·s.

[0032] In this embodiment, the silicone rubber of the silicone rubber sealing layer 1 comprises 80-100 parts by weight of a chain-like siloxane oligomer with hydroxyl or acetoxy active end groups, 6-10 parts by weight of filler, 0.5-2 parts by weight of crosslinking agent, 0.05-0.1 parts by weight of catalyst, and 6-9 parts by weight of curing agent. The chain-like siloxane oligomer with hydroxyl or acetoxy active end groups is a hydroxyl-terminated polydimethylsiloxane.

[0033] The chemical molecular structure of hydroxyl-terminated polydimethylsiloxane is as follows:

[0034] .

[0035] Because the main molecular chain is composed of silicon and oxygen atoms, the bond energy of the silicon-oxygen bond is about 370 kJ / mol, which gives it very high thermal stability. Because there are organic groups on the side groups, silicone rubber has the properties of resistance to high and low temperatures. Because silicone rubber is a non-polar molecule, it has electrical insulation properties. Because there are hydroxyl groups on the side groups, it is a viscous liquid at room temperature.

[0036] In this embodiment, the filler includes precipitated silica, calcium carbonate, kaolin, etc. The catalyst includes Bu₂Sn(OCOC) 11 H 23 )2.

[0037] In this embodiment, the curing agent includes tetraethyl orthosilicate and / or hydroxyaminosilane. The crosslinking agent includes a 1:1 mixture of MeSi(OAc)3 and EtSi(OAC)3.

[0038] This embodiment also provides a method for preparing a solid capacitor with good sealing performance, including the following steps:

[0039] 1) Preparation of silicone rubber;

[0040] 1.1) Mix the chain-like siloxane oligomers with active hydroxyl or acetoxy end groups and the filler evenly;

[0041] 1.2) Add the catalyst and / or curing agent to step 1) and mix thoroughly;

[0042] 1.3) Adjust the viscosity of the mixture from step 2) to 15–25 Pa·s and set aside for later use;

[0043] 2) Pour the silicone rubber prepared in step 1) into the mold;

[0044] 3) Immerse the core package into the silicone rubber in the mold. Because silicone rubber has fluidity and adhesion, its fluidity allows it to flow naturally and completely wrap the core package.

[0045] 4) Incubate the silicone rubber and core from step 3) at 40-60℃ for 5-10 minutes to allow the silicone rubber to crosslink and cure, thus obtaining the finished film capacitor. The reactions that occur during crosslinking and curing are as follows:

[0046]

[0047] .

[0048] In this embodiment, compared with the traditional epoxy resin potting process for film capacitors, the only difference is that the traditional epoxy resin potting process is replaced by silicone rubber impregnation or potting, thereby forming a silicone rubber sealing layer on the core package surface. The silicone rubber sealing layer can directly serve as the outer shell of the product. The relevant specifications and core package parameters can be printed on the surface of the silicone rubber sealing layer 1 by laser printing. After testing and packaging, it can be shipped to the customer for use.

[0049] Currently, epoxy resin is mainly used for potting. For larger plastic-cased film capacitors, potting requires two to three steps to ensure proper encapsulation. First, a small amount of epoxy resin is poured into the plastic casing and heated to cure. Then, the core is placed in the casing, more epoxy resin is added, and the casing is heated to cure again. This process slows down production and reduces efficiency. Furthermore, single-stage potting can easily lead to issues such as core misalignment and incomplete encapsulation. The silicone rubber used in this embodiment employs an impregnation process, allowing for one-step core encapsulation without issues like core misalignment or incomplete encapsulation.

[0050] The product of this embodiment was subjected to a double 85 test (85°C, 85% relative humidity) simultaneously with a traditional product using potted epoxy resin. The traditional product failed after 600-1000 hours, while the product of this embodiment failed after 2000-3000 hours. This demonstrates that the film capacitor of this embodiment, due to its core being sealed with silicone rubber, has excellent sealing performance and fully meets the requirements of the double 85 test. Simultaneously, it meets the AEC-Q200 vibration test requirements. The AEC-Q200 vibration test parameters are: acceleration 10G / 20 minutes, 12 cycles in each of the three directions, and a test frequency from 10 to 2000 Hz.

[0051] Example 2

[0052] This embodiment provides a solid-state capacitor with good sealing performance, which is a multilayer solid aluminum electrolytic capacitor. During encapsulation, the core package 3 of the multilayer solid aluminum electrolytic capacitor is placed in a mold. A pre-mixed silicone rubber with a viscosity of 38-55 Pa·s is injected into the mold using an injection molding machine, ensuring uniform adhesion of the silicone rubber to the multilayer surface. The silicone rubber is then cross-linked and cured in the mold at 80-100°C for 2-4 minutes, resulting in the finished multilayer solid aluminum electrolytic capacitor. Figure 2 As shown, in the finished multilayer solid aluminum electrolytic capacitor, the silicone rubber sealing layer 1 completely encloses the core package 3; the leads extend out of the silicone rubber sealing layer 1. The other parts of this embodiment are the same as in Embodiment 1.

[0053] The product of this embodiment and a traditional product using epoxy resin injection were subjected to a double 85 test (temperature 85°C, relative humidity 85%). The traditional product failed after 100 to 300 hours, while the product of this embodiment failed after 2000 to 3000 hours. At the same time, it can also meet the AEC-Q200 vibration test requirements. The AEC-Q200 vibration test parameters are: acceleration 10G / 20 minutes, 12 cycles in each of the three directions, and test frequency from 10 to 2000 Hz.

Claims

1. A solid capacitor with good sealing performance, characterized in that: It includes a core package and a silicone rubber sealing layer. The silicone rubber sealing layer is formed on the surface of the core package by an impregnation process or a glue injection process. The silicone rubber sealing layer completely encapsulates and seals the core package.

2. The solid-state capacitor with good sealing effect according to claim 1, characterized in that: The viscosity of the silicone rubber forming the silicone rubber sealing layer is 15-55 Pa·s.

3. The solid capacitor with good sealing effect according to claim 1, characterized in that: The silicone rubber of the silicone rubber sealing layer includes chain siloxane oligomers with active hydroxyl or acetoxy end groups, fillers, crosslinking agents, and additives, wherein the additives include catalysts and / or curing agents.

4. The solid capacitor with good sealing effect according to claim 3, characterized in that: The chain-like siloxane oligomers with active hydroxyl or acetoxy end groups include hydroxyl-terminated polydimethylsiloxanes.

5. The solid capacitor with good sealing effect according to claim 3, characterized in that: The filler includes one or more of silica, calcium carbonate, and clay.

6. The solid capacitor with good sealing effect according to claim 3, characterized in that: The catalyst includes Bu2Sn(OCOC) 11 H 23 )2.

7. The solid capacitor with good sealing effect according to claim 3, characterized in that: The curing agent includes tetraethyl orthosilicate and / or hydroxyaminosilane.

8. The solid capacitor with good sealing effect according to claim 3, characterized in that: The crosslinking agent comprises a 1:1 mixture of MeSi(OAc)3 and EtSi(OAC)3.

9. A method for preparing a solid-state capacitor with good sealing performance, characterized in that, Includes the following steps: 1) Preparation of silicone rubber; 1.1) Mix the chain-like siloxane oligomers with active hydroxyl or acetoxy end groups and the filler evenly; 1.2) Add the catalyst and / or curing agent to step 1) and mix thoroughly; 1.3) Adjust the viscosity of the mixture from step 2) to 15–55 Pa·s and set aside for later use; 2) Pour the silicone rubber prepared in step 1) into the mold; 3) Immerse the core package into the silicone rubber inside the mold, so that the silicone rubber completely encapsulates the core package; 4) Keep the silicone rubber and core package from step 3) at a temperature of 40-100℃ for 2-10 minutes to allow the silicone rubber to crosslink and cure, thus obtaining the finished film capacitor.

10. A thin-film capacitor or a multilayer capacitor, characterized in that: The invention includes a silicone rubber sealing layer and a core package as described in any one of claims 1-8, wherein the silicone rubber sealing layer is formed on the surface of the core package by an impregnation process; the silicone rubber sealing layer completely encapsulates and seals the core package.

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