CN116052966A - Surface mounting overcurrent protection element - Google Patents

Abstract

The invention discloses a surface-mounted overcurrent protection element, which comprises at least one resistance positive temperature effect conductive composite material core material, wherein metal electrodes are required to be coated on two sides of the resistance positive temperature effect conductive composite material core material; at least one surface is provided with a conductive terminal which is electrically connected with a metal electrode of the core material of the material which is conductive according to the positive temperature effect of the resistor; four sides or four sides and one front of the conductive composite material core material are covered by plastic packages and isolated from the external environment. The surface-mounted overcurrent protection element disclosed by the invention is convenient for realizing batch production, and can meet the normal production of a parallel structure of a single-layer resistance positive temperature effect conductive composite material core material and a multi-layer resistance positive temperature effect conductive composite material core material, and meanwhile, the element has extremely high environmental performance and structural stability.

Description

Surface mounting overcurrent protection element

Technical Field

The invention relates to a device used in an electronic circuit as an overcurrent and overtemperature device, in particular to an overcurrent protection element capable of being surface-mounted.

Background

Surface-mounted components (SMD) prepared from conductive composite materials with positive temperature effects of resistance and resistance are widely applied to electronic circuits, and play a role in overcurrent and over-temperature protection in the electronic circuits. SMD PTC elements have been widely used because of their small size, ease of processing, etc. However, with the development of the demands of intellectualization, multifunctionality and power of electronic devices, smaller size, larger current capacity and more excellent environmental performance are a technical problem of the SMD products at present.

The traditional SMD PTC element is mainly finished by PCB processing, and the SMD PTC element prepared by adopting the traditional drilling, etching and other processes in the PCB with large size specification (0603 package and above) has enough structural strength and reliable battery core after reflow soldering. However, the SMD PPTC of this specification is a problem to be solved in terms of environmental reliability of the product, since the four sides of the product are exposed to the air.

Disclosure of Invention

The invention aims to solve the technical problem of providing the surface-mounted over-current thermal protection element, which can realize different size packaging, and has the characteristics of more stable product structure and more reliable environmental performance.

The surface-mounted overcurrent protection element comprises at least one core material, two terminal electrodes, two conductive terminals and a plastic sealing layer. Wherein the core material has positive temperature coefficient of resistance characteristics: 1. the side surface and one front surface of the protective element are provided with plastic layers, six surfaces of the protective element can be completely plastic-packaged, and only two conductive electrodes are reserved, so that the element high-molecular material base material is isolated from the air environment, and the element has higher environmental reliability; 2. the conductive members which play a role in electric connection are positioned at two sides of the core material with the positive temperature coefficient of resistance, so that the element is fully ensured to have good welding operability and good environmental performance; 3. the invention can normally produce single-layer PTC chip products, double-layer PTC chips and multi-layer PTC chip products, the product of the scheme has a single welding surface structure, and the plastic package at least wraps four sides and one front surface of the conductive composite material core material or six surfaces of the conductive composite material core material, and only exposes the conductive terminals to be used as bonding pads.

Based on the scheme, the plastic packaging 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.

On the basis of the scheme, 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.

Based on the above scheme, the conductive terminal can be a metal conductive structure component or consists of metal electrode foil, metal plating, alloy or plating metal.

On the basis of the scheme, the plastic packaging material wrapped by the surface-mounted overcurrent protection element is a non-conductive material and has the performance of blocking air and water vapor.

On the basis of the scheme, the surface-mounted overcurrent protection element is of a single-sided pad design or a double-sided pad design.

Based on the above scheme, the core material with positive temperature coefficient of resistance characteristic, wherein the high polymer material is selected from one of polyethylene, chlorinated polyethylene, oxidized polyethylene, polyvinyl chloride, butadiene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, polystyrene, polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polyoxymethylene, phenolic resin, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polytrifluoroethylene, polyvinylfluoride, maleic anhydride grafted polyethylene, polypropylene, polyvinylidene fluoride, epoxy resin, ethylene-vinyl acetate copolymer, polymethyl methacrylate, ethylene-acrylic acid copolymer and mixtures thereof.

Based on the above scheme, the core material with positive temperature coefficient of resistance is prepared from one of carbon black, graphite, carbon fiber, carbon nanotube, metal powder, conductive ceramic powder and mixture thereof. The metal powder is selected from: copper, nickel, cobalt, iron, tungsten, tin, lead, silver, gold, platinum or an alloy thereof, and mixtures thereof. The conductive ceramic powder is selected from the group consisting of: one or a mixture of a plurality of metal nitrides, metal carbides, metal borides and metal silicides.

The positive temperature effect resistance composite material and the positive temperature effect resistance core material prepared from the conductive composite material can be prepared according to the following method:

the polymer material, the conductive filler, other auxiliary agents or auxiliary fillers are added to the mixing device and kneaded at a temperature higher than the melting temperature of the polymer material. The mixing apparatus may be an internal mixer, an open mill, a single screw extruder or a twin screw extruder. The melt-mixed polymer is then processed into a sheet, which may also be accomplished by extrusion, compression molding, or a piece of a spreader Bao Tongla. In general, the thickness of the polymer sheet is 0.10 to 0.55mm, preferably 0.15 to 0.45mm, more preferably 0.20 to 0.40mm for the convenience of processing.

The core material may generally be crosslinked or heat treated to improve the stability of the PTC chip performance.

The crosslinking may be chemical crosslinking or irradiation crosslinking, for example, crosslinking accelerators, electron beam irradiation or Co ⁶⁰ Irradiation is performed. The irradiation dose required for the PTC element is generally less than 100Mrad, preferably 1 to 50Mrad, more preferably 1 to 20Mrad.

The heat treatment may be annealing, thermal cycling, high and low temperature alternation, for example 80 ℃/-40 ℃. The temperature environment of the anneal may be any temperature below the decomposition temperature of the PTC material layer substrate, such as a high temperature anneal above the melting temperature of the conductive composite substrate and a low temperature anneal below the melting temperature of the conductive composite substrate;

the composite sheet material with the positive temperature coefficient effect of the resistor and the first conductive electrode and the second conductive electrode which are closely adhered on the two sides of the polymer material base layer form the composite sheet material, the conductive electrode of the composite sheet material is etched into an insulation groove through an inner layer pattern transfer etching technology, then two insulation layers are stacked on the two surfaces of the etched composite sheet material and respectively cover metal foils, high-temperature lamination is carried out, and then the laminated substrate is subjected to the following steps of tinning the outer layer metal foils, etching the outer layer patterns, printing solder resist ink, curing solder resist ink, drilling, copper deposition, copper plating and the like, so that the polymer PTC overcurrent protection element with the two end electrodes is obtained. And subsequently, welding the high-polymer overcurrent protection element with the two end electrodes on the conductive terminal through a welding process, and performing plastic package on four side surfaces and one upper surface of the product through an injection molding process to obtain the high-polymer overcurrent protection element with excellent environmental stability.

Drawings

FIG. 1 is a schematic diagram of a surface mount over-current thermal protection device;

fig. 2 is a schematic structural diagram of a surface mount overtemperature protection device according to a first embodiment;

fig. 3 is a schematic structural diagram of a surface mount overtemperature protection device according to a second embodiment;

fig. 4 is a schematic structural diagram of a surface mount overtemperature protection component in accordance with a third embodiment;

fig. 5 is a schematic structural diagram of a surface mount overtemperature protection device according to a fourth embodiment.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

The preparation process of the PTC core material is as follows:

proportioning a high polymer material and a conductive filler used for a positive temperature effect composite material layer according to the formula I, granulating the mixture components at 180 ℃ in a double-screw granulator, cooling, crushing, extruding by a single-screw extruder, and attaching electrode copper foils on an upper layer and a lower layer after the rolling of a calender to obtain a conductive composite material with the thickness of 0.20-0.40 mm, namely the core material;

according to the actual process requirement, carrying out 16Mrad irradiation on the PTC plate with the metal copper foil coated on the two sides, and carrying out PCB processing after heat treatment at 120 ℃ for 30 min;

the surface-mounted high-polymer PTC overcurrent protection element is manufactured through a PCB processing technology, and then is subjected to the procedures of cutting, welding of conductive terminals and plastic packaging, and in the manufacturing process, plastic packaging layers are added on four sides, five sides or six sides of the overcurrent protection element, so that an element high-polymer material base layer is isolated from an air environment, and the environmental reliability of a product is improved.

Example 1

A surface mount overtemperature protection component with a welding surface and high environmental reliability is prepared by the following steps as shown in figure 2:

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 and 6 on an upper layer and a lower layer after the extrusion of a calender, and pressing into a high-polymer composite material base layer 5 with the area of 400 square centimeters and the thickness of 0.3mm to obtain a high-polymer PTC composite sheet with two-sided composite electrode foils; after heat treatment for 0.5 hours at 120 ℃ in a vacuum oven, gamma rays (Co 60) are used for irradiation, the dosage is 16Mrad, then the composite sheet is subjected to PCB processing technology, the first conductive electrode 4 and the second conductive electrode 6 are respectively etched into insulation grooves through PCB etching technology, then an insulation layer 3 is overlapped between the first conductive electrode 4 and a metal foil, meanwhile, the other insulation layer 3 (a) is overlapped between the second conductive electrode 6 and the other metal foil, 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, solder resist ink printing and the like to form a first end electrode 1 and a second end electrode 2; then, two conductive members, namely a first conductive member 7 and a second conductive member 8, are formed through subsequent drilling, copper deposition and tin plating; and then, the product processed by the PCB is subjected to reflow soldering to form two conductive terminals 9 and 10, and then, the four side surfaces and the upper surface of the overcurrent protection element are subjected to plastic package 11 through a plastic package process, so that the high-polymer PTC overcurrent protection element with one soldering surface and high environmental reliability is prepared.

Example two

A high molecular PTC overcurrent protection element with a welding surface and high environmental reliability is prepared by the following steps as shown in figure 3:

mixing high-density polyethylene and metal tungsten carbide in a high-speed mixer according to a certain proportion for 30min, granulating the mixture components at 180 ℃ in a double-screw granulator, cooling, crushing, extruding by a single-screw extruder, attaching electrode foils on an upper layer and a lower layer after the rolling of a calender, and pressing into a high-polymer composite material base layer 5 with the area of 400 square centimeters and the thickness of 0.3 mm; the polymer PTC composite sheet with the double-sided electrode foils 4 and 6 is obtained, and is irradiated by gamma rays (Co 60) with the dosage of 16Mrad after being heat treated for 0.5 hour at 120 ℃ in a vacuum oven; then, through a PCB processing technology, the composite sheet material respectively etches the first conductive electrode 4 and the second conductive electrode 6 into insulation grooves through a PCB etching technology, then an insulation layer 3 is overlapped between the first conductive electrode 6 and a metal foil, meanwhile, another insulation layer 3 (a) is overlapped between the second conductive electrode 6 and another metal foil, then high-temperature lamination is carried out, and the laminated substrate is subjected to steps of end electrode tinning, outer layer pattern etching, solder resist ink printing and the like to form a first end electrode 1 and a second end electrode 2; then, two conductive members, namely a first conductive member 7 and a second conductive member 8, are formed through subsequent drilling, copper deposition and tin plating; and the product processed by the PCB is subjected to reflow soldering to form two conductive terminals 9 and 10, and then four sides of the overcurrent protection element are subjected to plastic package 11 by a plastic package process, so that the high-polymer PTC overcurrent protection element with one soldering surface and high environmental reliability is prepared.

Example III

A high molecular PTC overcurrent protection element with a welding surface and high environmental reliability is prepared by the following steps as shown in figure 4:

mixing high-density polyethylene and metal tungsten carbide in a high-speed mixer according to a certain proportion for 30min, granulating the mixture components at 180 ℃ in a double-screw granulator, cooling, crushing, extruding by a single-screw extruder, attaching electrode foils on an upper layer and a lower layer after the rolling of a calender, and pressing into a high-polymer composite material base layer 5,5a with the area of 400 square centimeters and the thickness of 0.3 mm; the polymer PTC composite sheet (4, 5, 6 and 4a, 5a and 6 a) is obtained, after heat treatment for 0.5 hours at 120 ℃ in a vacuum oven, gamma rays (Co 60) are used for irradiation, the dosage is 16Mrad, then the composite sheet is etched into insulation grooves by a PCB etching technology through the PCB etching technology, then an insulation layer 3 is overlapped between the first conductive electrode 4 and a metal foil, meanwhile, another insulation layer 3 (a) is overlapped between the second conductive electrode 6 (a) and another metal foil, another insulation layer is overlapped between two layers of polymer PTC composite sheet, then high-temperature lamination is carried out, and the laminated substrate is plated with tin through the end electrode, outer layer pattern etching, solder resist ink printing and other steps to form a first end electrode 1 and a second end electrode 2; then, two conductive members, namely overcurrent protection elements of the first conductive member 7 and the second conductive member 8, are formed through subsequent drilling, copper deposition and tin plating, so that two layers are formed; and the over-current protection element processed by the PCB is subjected to reflow soldering to form two conductive terminals 9 and 10, and then four side surfaces and the upper surface of the over-current protection element are subjected to plastic package through a plastic package process, so that the high-polymer PTC over-current protection element with one soldering surface and high environmental reliability is prepared. (refer to FIG. 4).

Example IV

A high molecular PTC overcurrent protection element with a welding surface and high environmental reliability is prepared by the following steps as shown in figure 5:

mixing high density polyethylene and metal tungsten carbide in a certain proportion in a high speed mixer for 30min. Granulating the mixture components at 180 ℃ in a double-screw granulator, cooling, crushing, extruding by a single-screw extruder, attaching electrode foils on the upper layer and the lower layer after the rolling of a calender, and pressing into a high polymer composite material base layer with the area of 400 square centimeters and the thickness of 0.3mm (marks 5 and 5 a). The polymer PTC composite sheet (combination of reference numerals 4, 5, 6 and 4a, 5a and 6 a) was obtained, and after heat treatment in a vacuum oven at 120℃for 0.5 hours, gamma rays (Co 60) were irradiated at a dose of 16Mrad. And then, through a PCB processing technology, the composite sheet material is subjected to the steps of respectively etching an insulating groove on a first conductive electrode (4, 4 a) and a second conductive electrode (6, 6 a) through a PCB etching technology, then, an insulating layer (3) is overlapped between the first conductive electrode and a metal foil, meanwhile, another insulating layer (3 (a) is overlapped between the second conductive electrode (6) and another metal foil, another insulating layer is overlapped between the combination of the marks 4, 5 and 6 and the combination of the marks 4a and 5a and 6a, then, high-temperature lamination is carried out, and a laminated substrate is subjected to the steps of end electrode tinning, outer layer pattern etching, printing solder resist ink and the like, so as to form a first end electrode (1) and a second end electrode (2), and then, through subsequent steps of drilling, copper deposition, tinning, so as to form two conductive members, namely, an overcurrent protection element of the first conductive member (7) and the second conductive member (8), and then, the overcurrent protection element after the processing is subjected to the reflow soldering of two conductive terminals (9 and 10), and then, the four overcurrent protection elements are subjected to the high-temperature sealing process, so that the PTC element is subjected to the high-temperature sealing and environmental protection (5) and the PTC protection element.

The invention can also be realized by connecting three layers or more than three layers of composite sheets in parallel and adopting the same conduction mode, and obtains the overcurrent protection element with excellent environmental reliability through welding the conductive terminal and plastic packaging.

While the foregoing invention has been described in some detail by way of illustration and example, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention. Accordingly, the scope of the present invention should not be limited to the embodiments disclosed, but should include all combinations of what is presented in the different sections, as well as various alternatives and modifications, without departing from the 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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