CN116052966A - A surface mount overcurrent protection component - Google Patents

Abstract

The invention discloses a surface-mounted overcurrent protection element, which has at least one positive resistance temperature effect conductive composite material core material, and the two sides of the resistance positive temperature effect conductive composite material core material need to be covered with metal electrodes; at least one side has a conductive terminal, It is electrically connected with the metal electrode of the positive temperature effect conductive composite material core material of resistance; the four sides or four sides and one front side of the conductive composite material core material are covered by plastic packaging, and are isolated from the external environment. The surface-mounted overcurrent protection element disclosed by the invention is convenient for mass production, and satisfies the normal production of a single-layer resistance positive temperature effect conductive composite material core material and a multilayer resistance positive temperature effect conductive composite material core material in parallel structure, and at the same time, the element has High environmental performance and structural stability.

Description

A surface mount overcurrent protection component

technical field

The invention relates to an over-current and over-temperature device used in electronic circuits, specifically a surface mountable over-current protection element.

Background technique

Surface mount components (SMD) made of conductive composite materials with positive temperature effect of resistance and resistance are widely used in electronic circuits, and play the role of over-current and over-temperature protection in electronic circuits. SMD PTC components have been widely used because of their small size and easy processing. However, with the development of intelligent, multi-functional, and power-oriented electronic equipment, smaller size, greater flow capacity, and better environmental performance are technical problems for SMD products at this stage.

Existing SMD PTC components are mainly completed by PCB processing, large-size specifications (0603 package and above) SMD PTC components prepared by traditional drilling, etching and other processes in PCB still have sufficient structural strength and reliable batteries after reflow soldering . However, because the four sides of the SMD PPTC of this specification are exposed to the air, the environmental reliability of the product is a problem that needs to be solved.

Contents of the invention

The technical problem to be solved by the present invention is to provide a surface mount over-current and over-temperature protection component, which can be packaged in different sizes, has more stable product structure and more reliable environmental performance.

The surface mounting overcurrent protection component of the present invention comprises at least one core material, two terminal electrodes, two conductive terminals and a plastic sealing layer. Among them, the core material has the characteristics of positive temperature coefficient of resistance: 1. The side and one front side of the protective element have a plastic sealing layer, and all six sides of the protective element can be plastic-sealed, leaving only two conductive electrodes, so that the polymer material substrate of the element is in contact with the The air environment is isolated, so that the components have high environmental reliability; 2. The conductive components for electrical connection are located on both sides of the core material with positive temperature coefficient of resistance characteristics, which fully ensures that the components have good welding operability, and Make the components have good environmental performance; 3. The present invention can normally produce single-layer PTC chip products, double-layer PTC chip products and multi-layer PTC chip products. The product of this scheme has a single welding surface structure, and the plastic packaging at least wraps the conductive composite material The four sides and one front side of the core material or the six sides of the core material of the conductive composite material only expose the conductive terminals to be used as pads.

On the basis of the above scheme, the plastic sealing material is thermosetting liquid epoxy resin, phenolic resin, polyimide, or inorganic filler modified epoxy resin, glass fiber or epoxy resin and other fillers. mixture.

On the basis of the above solution, at least four sides of the conductive composite core material are plastic-wrapped by one of plastic sealing molding, compression molding, compression molding, injection molding, transfer molding, and thermosetting molding.

On the basis of the above solution, the conductive terminal may be a metal conductive structural component, or be composed of metal electrode foil, metal plating, alloy or plating metal.

On the basis of the above solution, the plastic packaging material of the surface mount overcurrent protection component is a non-conductive material, and has the performance of blocking air and water vapor.

On the basis of the above solution, the surface mount overcurrent protection component is designed with single-sided pads or double-sided pads.

On the basis of the above scheme, the core material with positive temperature coefficient of resistance, wherein the polymer material is selected from polyethylene, chlorinated polyethylene, oxidized polyethylene, polyvinyl chloride, butadiene-acrylonitrile copolymer Acrylonitrile-butadiene-styrene copolymer, polystyrene, polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, poly Phenyl sulfide, polyoxymethylene, phenolic resin, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polytrifluoroethylene, polyvinyl fluoride, maleic anhydride grafted polyethylene, polypropylene, polyvinylidene fluoride, One of epoxy resin, ethylene-vinyl acetate copolymer, polymethyl methacrylate, ethylene-acrylic acid copolymer and a mixture thereof.

On the basis of the above scheme, the core material with positive temperature coefficient of resistance, wherein the conductive material is selected from one of carbon black, graphite, carbon fiber, carbon nanotube, metal powder, conductive ceramic powder and a mixture thereof . The metal powder is selected from one of copper, nickel, cobalt, iron, tungsten, tin, lead, silver, gold, platinum or alloys thereof and a mixture thereof. The conductive ceramic powder is selected from one or a mixture of metal nitrides, metal carbides, metal borides and metal silicides.

The resistance positive temperature effect composite material of the present invention and the resistance positive temperature effect core material prepared by the conductive composite material can be prepared according to the following method:

Add polymer materials, conductive fillers, other additives or auxiliary fillers to the mixing equipment, and knead at a temperature higher than the melting temperature of the polymer materials. The mixing equipment can be internal mixer, open mill, single screw extruder or twin screw extruder. The melt-mixed polymer is then processed into a sheet, which can also be achieved by extrusion, compression molding, or milling. Generally, the thickness of the polymer sheet is 0.10-0.55 mm, preferably 0.15-0.45 mm, more preferably 0.20-0.40 mm for the convenience of processing.

The core material can generally improve the performance stability of the PTC chip by means of cross-linking or heat treatment.

The cross-linking can be chemical cross-linking or radiation cross-linking, for example, it can be realized by using a cross-linking accelerator, electron beam irradiation or Co ⁶⁰ irradiation. The radiation dose required by the PTC element is generally less than 100 Mrad, preferably 1-50 Mrad, more preferably 1-20 Mrad.

The heat treatment can be annealing, thermal cycle, high and low temperature alternating, for example, 80°C/-40°C high and low temperature alternating. The temperature environment of the annealing can be any temperature below the decomposition temperature of the PTC material layer base material, such as high temperature annealing higher than the melting temperature of the conductive composite material base material and low temperature annealing lower than the melting temperature of the conductive composite material base material;

The composite material sheet produced by the above-mentioned positive temperature coefficient of resistance and the first conductive electrode and the second conductive electrode closely attached to the two sides of the above-mentioned polymer material base layer form a composite sheet, and the composite sheet is transferred and etched through the inner layer pattern The technology enables the conductive electrodes of the composite sheet to etch out insulating grooves, and then, two insulating layers are stacked on both surfaces of the etched composite sheet, and covered with metal foil respectively, and then pressed at high temperature, and then the pressed substrate is subjected to subsequent Tinning the outer layer metal foil, etching the outer layer pattern, printing solder resist ink, curing solder resist ink, drilling, sinking copper, copper plating process and other steps to obtain a polymer PTC overcurrent protection component with two terminal electrodes . Subsequent welding process, the polymer overcurrent protection element with two terminal electrodes is welded on the conductive terminal by welding process, and the four sides and one upper surface of the product are plastic-sealed by injection molding process to obtain an excellent environment. Stable polymer overcurrent protection element.

Description of drawings

Figure 1 is a schematic structural view of a surface mount overcurrent and overtemperature protection component;

Fig. 2 is the structural representation of the surface mount overcurrent and overtemperature protection element of embodiment one;

Fig. 3 is the structural representation of the surface mount overcurrent and overtemperature protection element of embodiment two;

Fig. 4 is the structural representation of the surface mount overcurrent and overtemperature protection element of embodiment three;

Fig. 5 is a schematic structural view of the surface mount overcurrent and overtemperature protection element of the fourth embodiment.

Detailed ways

The present invention will be described in further detail below through specific examples.

The preparation process of PTC core material is as follows:

According to the ratio of polymer materials and conductive fillers used in the composite material layer according to the resistance positive temperature effect as shown in Table 1, the mixture components are granulated in a twin-screw granulator at a temperature of 180 ° C, cooled, and pulverized Extrude through a single-screw extruder, and then attach electrode copper foil to the upper and lower layers after calendering to obtain a conductive composite material with a thickness of 0.20-0.40 mm, that is, the core material;

According to the actual process requirements, the PTC board made of metal copper foil on both sides is irradiated at 16Mrad, and processed after 120°C and 30min heat treatment;

Through the PCB processing technology, the surface mount type polymer PTC overcurrent protection component is made, and then it is cut, welded with conductive terminals, and plastic sealing process. During the manufacturing process, the four sides, five sides or The plastic sealing layer is added on the six sides to isolate the base layer of the polymer material of the component from the air environment, thereby improving the environmental reliability of the product.

Embodiment one

A surface mount overcurrent and overtemperature protection component with a soldering surface and high environmental reliability, as shown in Figure 2, is prepared according to the following steps:

After mixing high-density polyethylene and metal tungsten carbide in a high-speed mixer in a certain proportion for 30 minutes, the mixture components are granulated in a twin-screw granulator at a temperature of 180 ° C, cooled, crushed, and passed through a single-screw extruder Extrude, and then attach electrode foils 4 and 6 to the upper and lower layers after calendering, and press to form an area of 400 square centimeters and a polymer composite base layer 5 with a thickness of 0.3 mm, to obtain a polymer PTC composite sheet with composite electrode foils on both sides material; after heat treatment at 120°C in a vacuum oven for 0.5 hours, irradiate with gamma rays (Co60) at a dose of 16 Mrad, and then use PCB processing technology to make the composite sheet through PCB etching technology to make the first conductive electrode 4 and the second conductive electrode 4. The electrodes 6 are respectively etched with insulating grooves, and then an insulating layer 3 is superposed between the first conductive electrode 4 and a metal foil, and at the same time, another insulating layer 3 (a) is superimposed on the second conductive electrode 6 and another metal foil. between the foils, and then carry out high-temperature pressing, and the pressed substrates go through steps such as terminal electrode tinning, outer pattern etching, printing solder resist ink, etc., to form the first terminal electrode 1 and the second terminal electrode 2; and then through the subsequent Drilling, sinking copper, and tinning to form two conductive members, which are the first conductive member 7 and the second conductive member 8 respectively; the products after PCB processing are subsequently soldered to the two conductive terminals 9 and 10 by reflow soldering, and then passed In the plastic sealing process, the four sides and the upper surface of the above-mentioned overcurrent protection element are plastic-encapsulated 11, thereby preparing a polymer PTC overcurrent protection element with one welding surface and high environmental reliability.

Embodiment two

A polymer PTC overcurrent protection element with a welding surface and high environmental reliability, as shown in Figure 3, is prepared according to the following steps:

After mixing high-density polyethylene and metal tungsten carbide in a high-speed mixer in a certain proportion for 30 minutes, the mixture components are granulated in a twin-screw granulator at a temperature of 180 ° C, cooled, crushed, and passed through a single-screw extruder After extruding, after calendering, the upper and lower layers of the electrode foil are attached, and pressed to form an area of 400 square centimeters and a thickness of 0.3mm. The polymer composite material base layer 5; that is, the polymer PTC with double-sided electrode foils 4 and 6 is obtained. The composite sheet is heat-treated in a vacuum oven at 120°C for 0.5 hours, and then irradiated with γ-rays (Co60) at a dose of 16Mrad; after that, the composite sheet is processed by PCB etching technology to make the first conductive electrode 4 and the second conductive electrode 4. The two conductive electrodes 6 are respectively etched with insulating grooves, and then an insulating layer 3 is superimposed between the first conductive electrode 6 and a metal foil, and another insulating layer 3 (a) is superimposed on the second conductive electrode 6 and the other Between the metal foils, high-temperature pressing is carried out, and the pressed substrate is subjected to steps such as terminal electrode tinning, outer pattern etching, and printing of solder resist ink to form the first terminal electrode 1 and the second terminal electrode 2; Drilling, sinking copper, and tin plating to form two conductive members, which are the first conductive member 7 and the second conductive member 8; the PCB processed product will be reflow soldered to the two conductive terminals 9 and 10 afterward. The four sides of the above-mentioned overcurrent protection element are plastic-encapsulated 11 through a plastic encapsulation process, thereby preparing a polymer PTC overcurrent protection element with one welding surface and high environmental reliability.

Embodiment three

A polymer PTC overcurrent protection element with a welding surface and high environmental reliability, as shown in Figure 4, is prepared according to the following steps:

After mixing high-density polyethylene and metal tungsten carbide in a high-speed mixer in a certain proportion for 30 minutes, the mixture components are granulated in a twin-screw granulator at a temperature of 180 ° C, cooled, crushed, and passed through a single-screw extruder After extruding, the upper and lower layers of the electrode foil are attached to the upper and lower layers of the calender after calendering, and pressed into an area of 400 square centimeters and a thickness of 0.3mm. 6 and 4a, 5a, 6a), after heat treatment in a vacuum oven at 120°C for 0.5 hours, irradiated with γ-rays (Co60) at a dose of 16Mrad, and then through PCB processing technology, the composite sheet was made by PCB etching technology to make the first The conductive electrodes 4, 4a and the second conductive electrodes 6, 6a are respectively etched with insulating grooves, and then an insulating layer 3 is stacked between the first conductive electrode 4 and a metal foil, and another insulating layer 3 (a) is stacked at the same time Between the second conductive electrode 6 (a) and another metal foil, another layer of insulating layer is superimposed between two layers of polymer PTC composite sheets, and then high-temperature pressing is carried out, and the pressed substrate passes through the terminal electrode Tin plating, outer layer pattern etching, printing solder resist ink and other steps to form the first terminal electrode 1 and the second terminal electrode 2; and then through subsequent drilling, copper sinking, and tin plating to form two conductive components, respectively The overcurrent protection element of the first conductive member 7 and the second conductive member 8 has two layers; the overcurrent protection element after PCB processing is subsequently soldered to the two conductive terminals 9, 10 by reflow soldering, and then the above-mentioned The four sides and the upper surface of the overcurrent protection component are plastic-sealed, so that a polymer PTC overcurrent protection component with one welding surface and high environmental reliability is prepared. (Refer to Figure 4).

Embodiment four

A polymer PTC overcurrent protection element with a welding surface and high environmental reliability, as shown in Figure 5, is prepared according to the following steps:

Mix high-density polyethylene and metal tungsten carbide in a high-speed mixer for 30 minutes in a certain proportion. Then the mixture components are granulated in a twin-screw granulator at a temperature of 180°C, cooled, crushed, extruded through a single-screw extruder, and then rolled by a calender with two upper and lower layers of electrode foil attached, and pressed into The area is 400 square centimeters, and the base layer of polymer composite material (label 5, 5a) is 0.3 mm thick. That is to say, polymer PTC composite sheets (combination of labels 4, 5, 6 and 4a, 5a, 6a) were obtained, which were heat-treated in a vacuum oven at 120°C for 0.5 hours, and then irradiated with gamma rays (Co60) at a dose of 16Mrad. Afterwards, through PCB processing technology, the composite sheet is etched with insulating grooves for the first conductive electrode (mark 4, 4a) and the second conductive electrode (mark 6, 6a) respectively through PCB etching technology, and then an insulating layer (mark 3 ) is stacked between the first conductive electrode and a metal foil, and another insulating layer (mark 3(a) is stacked between the second conductive electrode (mark 6) and another metal foil, and another insulating layer Superimposed between the combinations of labels 4, 5, and 6 and the combinations of 4a, 5a, and 6a, and then subjected to high-temperature lamination, the laminated substrates undergo steps such as tinning of terminal electrodes, etching of outer layer patterns, and printing of solder resist ink to form the first One terminal electrode (label 1) and the second terminal electrode (label 2). Then, after subsequent drilling, copper sinking, and tin plating, two conductive members are formed, which are the first conductive member (label 7) and the second conductive member. The overcurrent protection element of the component (label 8). Subsequent reflow soldering of the overcurrent protection element after PCB processing with two conductive terminals (label 9, 10), and then through the plastic packaging process, four of the above overcurrent protection elements The side is plastic-sealed to prepare a polymer PTC overcurrent protection element with one welding surface and high environmental reliability (Figure 5).

The present invention can also be realized by parallel connection of three or more layers of composite sheets, using the same conduction mode, and by welding conductive terminals and performing plastic sealing, an overcurrent protection element with excellent environmental reliability can be obtained.

The content and technical characteristics of the present invention have been disclosed as above, but the inventions described above are only briefly or only relate to specific parts of the present invention, so those skilled in the art may make various modifications based on the teachings and disclosures of the present invention without departing from the present invention. replacement and modification. Therefore, the protection scope of the present invention should not be limited to the contents disclosed in the embodiments, but should include combinations of all the contents presented in different parts, as well as various replacements and modifications that do not depart from the present invention.

Claims (8)

1. The utility model provides a surface mounting overcurrent protection element which characterized in that: comprising the following steps:

at least one composite sheet having a positive temperature coefficient of resistance effect comprising:

(a) A conductive composite substrate having a positive temperature coefficient of resistance effect;

(b) A first conductive electrode positioned on a first surface of the positive temperature coefficient of resistance effect composite material sheet;

(c) The second conductive electrode is positioned on the second surface of the composite material sheet with the positive temperature coefficient of resistance effect;

a conductive member electrically connected to one of the conductive electrodes in the composite sheet and electrically disconnected from the corresponding other conductive electrode;

3) The first insulating layer is adhered to the first conductive electrode of the element and is used for electrical isolation;

the second insulating layer is adhered to the second conductive electrode of the element and is used for electrical isolation;

4) A first end electrode disposed on one of the insulating layers, or on both of the insulating layers, and connected to one of the conductive members;

the second end electrode and the first end electrode are arranged on the same insulating layer or on two insulating layers, are electrically separated from the first end electrode and are connected with another conductive member;

5) The first conductive terminal is arranged on the first end electrode and is electrically connected with the first end electrode;

the second conductive terminal is arranged on the second end electrode and is electrically connected with the second end electrode;

6) The plastic sealing layer is arranged on four sides or four sides of the whole overcurrent protection element and an upper end face or six sides of the element; the first conductive terminal and the second conductive terminal are partially or entirely exposed.

2. The surface mount overcurrent protection element of claim 1, wherein: the plastic packaging material is solid epoxy resin, phenolic resin, polyimide or inorganic filler modified epoxy resin, glass fiber or mixture of epoxy resin and other fillers which can be processed by hot melting; or the plastic package material is thermosetting liquid epoxy resin, phenolic resin, polyimide or inorganic filler modified epoxy resin, glass fiber or mixture of epoxy resin and other fillers.

3. The surface mount overcurrent protection element of claim 1 or 2, wherein: the plastic package wraps at least four sides of the conductive composite material core material, and one of plastic package molding, compression molding, injection molding, transfer molding and thermosetting molding is adopted.

4. The surface mount overcurrent protection element of claim 1, wherein: the conductive terminal is a metal conductive structure component or is composed of metal electrode foil, metal plating, alloy or plating metal.

5. The surface mount overcurrent protection element of claim 1, wherein the composite sheet material having a positive temperature coefficient of resistance effect has two or more sheets connected in parallel by the conductive member.

6. A method of manufacturing the surface mount overcurrent protection element according to any one of claims 1 to 5, characterized by the steps of:

(1) Preparing a macromolecule PTC composite sheet: mixing high-density polyethylene and metal tungsten carbide in a high-speed mixer according to a certain proportion for 30min, granulating the mixture components in a double-screw granulator at 180 ℃, cooling, crushing, extruding by a single-screw extruder, attaching electrode foils (4, 6) on an upper layer and a lower layer after the extrusion of a calender, and pressing into a high-molecular composite material base layer (5) with the area of 400 square centimeters and the thickness of 0.3mm to obtain a high-molecular PTC composite sheet with double-sided composite electrode foils;

(2) After heat treatment in a vacuum oven at 120 c for 0.5 hours, gamma rays (Co 60) were irradiated at a dose of 16Mrad, after which,

(3) Respectively etching the first conductive electrode (4) and the second conductive electrode (6) into insulation grooves by a PCB (printed circuit board) processing technology through a PCB etching technology, then superposing an insulation layer (3) between the first conductive electrode (4) and a metal foil, superposing another insulation layer (3 (a)) between the second conductive electrode (6) and another metal foil, then performing high-temperature lamination, and forming a first end electrode (1) and a second end electrode (2) through the steps of end electrode tinning, outer layer pattern etching and solder resist ink printing of a laminated substrate; then, the process is carried out,

(4) Forming two conductive members, namely a first conductive member (7) and a second conductive member (8), through subsequent drilling, copper deposition and tin plating; subsequently, the product processed by the PCB is subjected to reflow soldering to obtain two conductive terminals (9, 10) to obtain a high polymer PTC overcurrent protection element; after that, the process is carried out,

(5) And (3) carrying out plastic packaging (11) on the four side surfaces and the upper surface of the overcurrent protection element through a plastic packaging process, so as to prepare the high-polymer PTC overcurrent protection element with one welding surface and high environmental reliability.

7. The method of manufacturing a surface mount overcurrent protection device according to claim 6, wherein in the step (5), four sides of the overcurrent protection device are subjected to plastic packaging, so that the polymer PTC overcurrent protection device with a welding surface and high environmental reliability is manufactured.

8. The method for manufacturing a surface mount overcurrent protection element according to claim 6, wherein in the step (1), the polymer PTC composite sheet is prepared as two superimposed layers, namely, comprising the polymer composite sheet (4, 5, 6) and the polymer composite sheet (4 a, 5a, 6 a);

in the step (3), through PCB processing technology, the composite sheet material is etched into insulating grooves through PCB etching technology respectively by the first conductive electrodes (4, 4 a) and the second conductive electrodes (6, 6 a), then an insulating layer (3) is overlapped between the first conductive electrodes (4) and a metal foil, meanwhile, another insulating layer (3 (a)) is overlapped between the second conductive electrodes (6 (a)) and another metal foil, another insulating layer is overlapped between the two layers of high polymer PTC composite sheet materials, then high-temperature lamination is carried out, and the laminated substrate is subjected to the steps of end electrode tin plating, outer layer pattern etching, printing solder resist ink to form a first end electrode (1) and a second end electrode (2).

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