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A kind of encapsulation molding method of varistor

A technology of varistors and molding methods, which is applied in the manufacture of encapsulation/housing resistors, etc., can solve the problems of increased man-hours and material costs, unstable pressure resistance performance, and long-term baking, etc., to reduce the consumption of protective materials, Stable external dimensions and reduced man-hours

Active Publication Date: 2022-07-08
XIAMEN SET ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 1. After dipping, the external dimension of the varistor is unstable (mainly reflected in the thickness). Unstable performance;
[0004] 2. Varistor components, such as the edge of the varistor, and the surface of the positive and negative electrodes are smooth. The current epoxy resin encapsulation powder, phenolic resin encapsulation powder, and silicone modified epoxy resin encapsulation powder are used. Due to the surface tension As a result, the partial area of ​​the varistor components cannot be dip-coated with encapsulating powder, and the varistor components cannot be completely wrapped. In high temperature and high humidity tests or actual applications such as photovoltaic power supplies and DC power supplies of photovoltaic inverters, due to The infiltration of water vapor and ionic compounds, and the ion migration is unidirectional, resulting in a sharp increase in the unidirectional leakage current of the varistor;
[0006] 4. When dipping, the encapsulation material will form water droplets at the bottom of the varistor due to gravity, which will affect the assembly of the miniaturized varistor module;
[0007] 5. Adopt the method of dip coating. Before dip coating, the welding electrodes need to be protected. At present, the protection mainly includes masking tape sticking or peelable coating. After the encapsulating material is dipped and cured, Then remove the protective material, which leads to an increase in man-hours and material costs; after the product is packaged, it needs to be baked for a long time, which is troublesome for the fixing and turnover of the product, and also increases the process cost;
[0008] 6. Using the above encapsulation materials, in the high and low temperature impact test, the encapsulation layer is prone to cracking; in the high temperature and high humidity test, due to the poor adsorption of the encapsulation material, the encapsulation material and the piezoresistor are not combined with each other, resulting in water Vapor will seep into the varistor along the pins, causing the varistor to deteriorate faster and lead to failure

Method used

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  • A kind of encapsulation molding method of varistor
  • A kind of encapsulation molding method of varistor
  • A kind of encapsulation molding method of varistor

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0045] The preparation method of the A component is:

[0046] Mix 51-52 parts of formula B hydroxyl-containing vinyl silicone oil, 1.5-3.5 parts of A formula hydroxyl-containing vinyl silicone oil and 0.1-0.3 parts of catalyst to obtain a first mixture;

[0047] Add 4-7.5 parts of white carbon black to the first mixture, and obtain the second mixture after mixing;

[0048] Add 12.5-17.5 parts of flame retardant and 17.5-22.5 parts of aluminum hydroxide to the second mixture in sequence, and obtain component A after mixing;

[0049] The preparation method of the B component is:

[0050] Mix 48-49 parts of formula B hydroxyl-containing vinyl silicone oil, 1.5-3.5 parts of A formula hydroxyl-containing vinyl silicone oil, 8-12 parts of low hydrogen-containing silicone oil and 0.1-0.3 parts of inhibitors to obtain a third mixture;

[0051] Add 4-7.5 parts of white carbon black to the third mixture, and obtain the fourth mixture after mixing;

[0052]Add 12.5-17.5 parts of flame...

Embodiment 1

[0077] Please refer to figure 1 , the first embodiment of the present invention is:

[0078] The encapsulation molding method of a varistor provided by the present invention comprises the following steps:

[0079] S1. Place the varistor component in the bottom mold of a forming mold;

[0080] Wherein, step S1 is specifically:

[0081] Apply solder paste on the silver surfaces of both sides of the varistor to be encapsulated;

[0082] The positive electrode sheet and the back electrode sheet of the to-be-encapsulated varistor are welded to obtain a varistor component.

[0083] Wherein, the number of the varistor components is more than two, and the two or more varistor components are distributed at a uniform interval along a preset direction. In this embodiment, one molding die can place 32PCS products (ie, varistor components). In this step, the manipulator can be imported, and 8 suction cups are installed on the manipulator to grab 8PCS products at one time, place the pr...

Embodiment 2

[0105] On the basis of Embodiment 1, the following features are further defined:

[0106] The preparation method of the silicone rubber in step S2 is:

[0107] S21, prepare A component and B component respectively;

[0108] The preparation method of the A component is:

[0109] Mix 51-52 parts of formula B hydroxyl-containing vinyl silicone oil, 1.5-3.5 parts of A formula hydroxyl-containing vinyl silicone oil and 0.1-0.3 parts of catalyst to obtain a first mixture;

[0110] Add 4-7.5 parts of white carbon black to the first mixture, and obtain the second mixture after mixing;

[0111] Add 12.5-17.5 parts of flame retardant and 17.5-22.5 parts of aluminum hydroxide to the second mixture in sequence, and obtain component A after mixing;

[0112] The preparation method of the B component is:

[0113]Mix 48-49 parts of formula B hydroxyl-containing vinyl silicone oil, 1.5-3.5 parts of A formula hydroxyl-containing vinyl silicone oil, 8-12 parts of low hydrogen-containing sili...

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Abstract

The invention relates to the technical field of varistors, and in particular, to a method for encapsulating and molding varistors, comprising the following steps: S1, placing a varistor component in a bottom mold of a molding die; S2, injecting silicone rubber into molding In the mold, a mold closing operation is performed after injection; S3, a heating and curing operation is performed on the mold after mold closing; S4, a mold opening is performed after heating and curing, to obtain an encapsulated varistor. After injection molding with silicone rubber, the external dimensions of the varistor are controlled by the molding die, the external dimensions are stable, and the tolerance can be controlled within ±0.1mm, so as to ensure the encapsulation thickness and ensure that the product meets the pressure resistance requirements and at the same time. Product structure requirements: Silicone rubber injection molding process is adopted. Before encapsulation, there is no need to protect the welding electrode surface of the varistor component, so as to meet the subsequent welding process and reduce labor hours and protective material consumption.

Description

technical field [0001] The invention relates to the technical field of varistors, in particular to a method for encapsulating and molding varistors. Background technique [0002] At present, in order to solve the moisture-proof and insulation problems of the varistor, it is necessary to encapsulate the varistor, and the encapsulation mainly adopts the dip coating process. The materials for dip coating mainly include epoxy resin encapsulation powder, phenolic resin encapsulation powder, and silicone modified epoxy resin encapsulation powder. The current method of dipping to encapsulate the varistor has the following disadvantages: [0003] 1. After dip coating, the external dimensions of the varistor are unstable (mainly reflected in the thickness), the main reason is that the encapsulation material becomes thicker with the operation time, resulting in unstable encapsulation thickness and pressure resistance. unstable performance; [0004] 2. Varistor components, such as t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01C17/02C08L83/07C08L83/05C08K7/26C08K3/22C08K13/04
CPCH01C17/02C08L83/04C08L2201/08C08L2205/025C08L2205/03C08K2003/2227C08L2203/20C08K7/26C08K3/22C08K13/04
Inventor 徐云辉张祥贵苏军陈小辉
Owner XIAMEN SET ELECTRONICS