Single-layer surface-mounted PPTC (Polymeric Positive Temperature Coefficient) element and preparation method thereof, and multi-layer surface-mounted PPTC element and preparation method thereof

Abstract

The invention discloses a single-layer surface-mounted PPTC (Polymeric Positive Temperature Coefficient) element and a preparation method thereof, and a multi-layer surface-mounted PPTC element and a preparation method thereof, and belongs to the technical field of thermistors. A single-layer surface-mounted PPTC element and a multi-layer surface-mounted PPTC element are manufactured on the basis of a basic composite unit, at least one electrode layer in the basic composite unit extends out relative to a PPTC core material to form an epitaxial electrode, and at least one bonding pad is formed by bending the epitaxial electrode. The multi-layer surface-mounted PPTC element is obtained by stacking a plurality of basic composite units and further processing the basic composite units, or by stacking the basic composite units and a PPTC substrate and further processing the basic composite units and the PPTC substrate. According to the invention, a process from etching to hole-aligning copper plating is abandoned and replaced by a process of bending an epitaxial electrode and coating or pasting an insulating material at a position needing insulation isolation, so that the processing process is simpler, the production cost is lower, and the production of more than three layers of surface-mounted PPTC elements becomes possible.

Description

Technical Field

[0001] The present invention relates to the technical field of thermistors, and in particular to a single-layer mounted PPTC component and a preparation method thereof, and a multi-layer mounted PPTC component and a preparation method thereof. Background Art

[0002] PPTC components, namely polymer positive temperature coefficient thermistors, also known as resettable fuses, can be used as overcurrent protection components. PPTC components include PPTC substrates and electrode plates or leads welded on the PPTC substrates. The PPTC substrates have PPTC core materials and metal foils arranged on both surfaces of the PPTC core materials. The PPTC core material is a polymer composite material obtained by filling conductive particles in a polymer and further processing it. The operating principle of the PPTC component is a kind of energy balance. When an overcurrent flows through the PPTC core material, heat will be generated due to Joule's law, and part of the generated heat energy will be dissipated into the environment. The part of the heat energy that is not dissipated will increase the temperature of the component.

[0003] After the PPTC component is applied to the circuit, under normal working conditions, the high molecular polymer and the conductive particle material are densely combined to form a crystalline structure. The PPTC core material shows an extremely low resistance value, which basically has no effect on the circuit performance; when an abnormal current occurs (such as overcurrent) or the ambient temperature rises, the high molecular polymer inside the PPTC core material causes thermal expansion due to self-heating caused by Joule heat, the distance between the internal conductive particles increases, the conductive particle molecules begin to break, and the conductive path is interrupted; when the fault is eliminated or the circuit is cut off, the self-heating stops, the PPTC core material undergoes thermal contraction, the distance between the conductive particles shortens, and the conductive path is reformed, and the circuit can return to normal working state.

[0004] In the production process of PPTC components, the raw materials are weighed according to the ratio, refined, granulated and molded to obtain the PPTC core material, and the PPTC core material 100, the first conductive layer 200 and the second conductive layer 300 are compounded to obtain a composite board (reference Figure 1 and Figure 2), the composite board is equivalent to a collection of several PPTC substrates. Depending on the type of PPTC element to be manufactured, the subsequent processing technology is different. For surface mount PPTC elements, it is necessary to etch insulation grooves on the first conductive layer 200 and the second conductive layer 300 respectively through PCB etching processing technology, and then superimpose the upper insulating layer 400 between the first conductive layer 200 and a metal foil; superimpose the lower insulating layer 500 between the second conductive layer 300 and another metal foil, and form a basic plate after high-temperature pressing. The basic plate is tinned by the end electrode, etched by the outer layer pattern, printed with solder resist ink, etc., to form the upper first end electrode 6001, the lower first end electrode 6002, the upper second end electrode 6003 and the lower second end electrode 6004, the upper solder resist ink for electrically isolating the upper first end electrode 6001 and the upper second end electrode 6003, and the lower solder resist ink for electrically isolating the lower first end electrode 6002 and the lower second end electrode 6004. After subsequent drilling, copper deposition and copper plating, a semicircular first conductive through hole 7001 connecting the upper first end electrode 6001, the lower first end electrode 6002 and the first conductive layer 200, and a semicircular second conductive through hole 7002 connecting the upper second end electrode 6003, the lower second end electrode 6004 and the second conductive layer 300 are formed.

[0005] Due to the complex manufacturing process, both single-layer and multi-layer surface mount PPTC components have the problem of high production costs and difficulty in improving production efficiency. In addition, it is very difficult to produce products with more than 3 layers because of the need for precise alignment between each layer. Summary of the invention

[0006] One of the purposes of the present application is to overcome the defects of the prior art surface-mounted PPTC components, which have high production costs and are difficult to improve production efficiency due to the complex manufacturing process, and thus a single-layer surface-mounted PPTC component and a preparation method, and a multi-layer surface-mounted PPTC component and a preparation method are proposed.

[0007] To achieve the above object, the present invention provides the following technical solution.

[0008] A single-layer surface-mount PPTC component is made on the basis of a basic composite unit, wherein the basic composite unit comprises a first electrode layer, a PPTC core material, and a second electrode layer arranged in sequence, wherein the first electrode layer extends relative to a first side surface of the PPTC core material to form a first epitaxial electrode;

[0009] Among them, the first epitaxial electrode is bent along the PPTC core material and partially covers the second electrode layer, and an insulating material for electrical isolation is arranged between the first epitaxial electrode and the second electrode layer; the first electrode layer is partially exposed to form one or more first soldering pads, and the second electrode layer is partially exposed to form one or more second soldering pads. In the single-layer surface-mounted PPTC component, at least one outer surface has both the first soldering pad and the second soldering pad.

[0010] Optionally, the end of the second electrode layer corresponding to the first side does not extend out of the PPTC core material, the end of the second electrode layer corresponding to the second side of the PPTC core material does not extend out of the PPTC core material, and the second side and the first side are arranged opposite to each other; and / or,

[0011] The area on the second electrode layer between the first pad and the second pad is covered with an insulating material; and / or,

[0012] A side of the single-layer surface-mount PPTC component opposite to the first side is covered with an insulating material; and / or,

[0013] The first electrode layer comprises a first composite part composited on the first surface of the PPTC core material, and a side of the first composite part facing away from the PPTC core material is covered with an insulating material; and / or,

[0014] The side of the first electrode layer facing away from the first side surface is covered with an insulating material; and / or,

[0015] The first electrode layer is isolated from the first side surface by an insulating material.

[0016] Optionally, the first pad and the second pad are located on the same surface of the single-layer surface-mount PPTC component.

[0017] Optionally, the end of the second electrode layer opposite to the first side surface of the PPTC core material is bent along the PPTC core material and partially covers the first electrode layer, and an insulating material for electrical isolation is arranged between the bent portion of the second electrode layer and the first electrode layer, and the portion of the second electrode layer covering the first electrode layer forms the second welding pad; wherein, the first composite portion of the first electrode layer composited on the PPTC core material has another first welding pad; and / or, the second composite portion of the second electrode layer composited on the PPTC core material has another second welding pad.

[0018] The two first pads are arranged opposite to each other; and / or,

[0019] A first composite portion of the first electrode layer composited on the first surface of the PPTC core material, the side facing away from the PPTC core material, is partially covered with an insulating material; and / or,

[0020] The two second pads are arranged opposite to each other; and / or,

[0021] The second composite part of the second electrode layer composited with the second surface of the PPTC core material has a side facing away from the PPTC core material partially covered with an insulating material.

[0022] Optionally, the first composite part of the first electrode layer is composited on the first surface of the PPTC core material; and / or the second composite part of the second electrode layer is composited on the second surface of the PPTC core material.

[0023] A multi-layer surface-mount PPTC component is made on the basis of a plurality of basic composite units, wherein the basic composite units include a PPTC core material and two electrode layers respectively arranged on two surfaces of the PPTC core material, and at least one of the electrode layers has an epitaxial electrode extending relative to the PPTC core material;

[0024] Wherein: each of the basic composite units is stacked in the thickness direction, one electrode layer of each of the basic composite units is electrically connected to each other, and the electrode layer located at or near the outer surface is partially exposed to form a first welding pad; another electrode layer of each of the basic composite units is electrically connected to each other, and the electrode layer located at or near the outer surface is partially exposed to form a second welding pad; each electrode layer corresponding to the first welding pad is electrically isolated from each electrode layer corresponding to the second welding pad; in the multi-layer surface-mounted PPTC component, at least one outer surface has both the first welding pad and the second welding pad.

[0025] Optionally, two adjacent basic composite units are insulated, isolated and fixed by insulating materials, and two electrode layers between two adjacent PPTC core materials correspond to the first welding pad and the second welding pad respectively; or,

[0026] The two adjacent PPTC core materials are electrically connected and are fitted and fixed.

[0027] Optionally, in each electrode layer corresponding to the first welding pad: at least one electrode layer forms a first conductive portion extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the first conductive portion of the electrode layer to form the first welding pad;

[0028] In each electrode layer corresponding to the second welding pad: at least one electrode layer forms a second conductive portion extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the second conductive portion of the electrode layer to form a second welding pad.

[0029] Optionally, the two electrode layers of the basic composite unit are respectively a first electrode layer and a second electrode layer, and the PPTC core material has a first side surface and a second side surface that are arranged opposite to each other, wherein:

[0030] In the first basic composite unit, the first electrode layer includes a first epitaxial electrode extending relative to the first side, and the second electrode layer includes a first epitaxial electrode extending relative to the second side; in the second basic composite unit, the first electrode layer includes a first epitaxial electrode extending relative to the first side, and the second electrode layer does not extend from the first side and the second side;

[0031] In the multi-layer surface-mount PPTC component, each of the basic composite units adopts the first basic composite unit, or each of the basic composite units adopts the second basic composite unit, or a part of each of the basic composite units adopts the first basic composite unit and the other part adopts the second basic composite unit.

[0032] Optionally, the multi-layer surface mount PPTC component is double-layer, wherein:

[0033] Two basic composite units both adopt the first basic composite unit, the two first electrode layers are electrically connected, and a first welding pad is formed at each of the two outer surfaces of the multi-layer surface-mounted PPTC component, the two second electrode layers are electrically connected, and a second welding pad is formed at each of the two outer surfaces of the multi-layer surface-mounted PPTC component, and the first welding pad formed by the first epitaxial electrode and the second welding pad formed by the second epitaxial electrode are located at different outer surfaces of the multi-layer surface-mounted PPTC component; or,

[0034] Two basic composite units both use the second basic composite unit, the electrode layers between the two PPTC core materials are electrically connected, one of the first epitaxial electrodes is bent to form the first welding pad, and the other first epitaxial electrode is bent to form the second welding pad; or,

[0035] The two basic composite units respectively adopt the first basic composite unit and the second basic composite unit, and two first epitaxial electrodes form a first welding pad on each of the two outer surfaces of the multi-layer surface-mounted PPTC component.

[0036] Optionally, the multi-layer surface-mounted PPTC component is made of a plurality of the first basic composite units, the two electrode layers between adjacent PPTC core materials are insulated, and the two epitaxial electrodes located on the outer surface of the multi-layer surface-mounted PPTC component are respectively bent to opposite sides to form the first welding pad and the second welding pad respectively located on the two outer surfaces; or,

[0037] The multi-layer surface mount PPTC component is made of one or more of the first basic composite units and one second basic composite unit, and the second basic composite unit is located at one end of the multi-layer surface mount PPTC component.

[0038] Optional,

[0039] The outermost electrode layer of the multi-layer surface-mounted PPTC component is partially covered with insulating material.

[0040] Optionally, the thickness of each of the PPTC core materials is the same, or the thickness of at least one PPTC core material is different from that of other PPTC core materials;

[0041] Each of the PPTC core materials is made of the same known material, or at least one PPTC core material is made of a known material different from that of other PPTC core materials.

[0042] A multi-layer surface mount PPTC component is made on the basis of a basic composite unit and a PPTC substrate;

[0043] The basic composite unit comprises a first electrode layer, a PPTC core material and a second electrode layer arranged in sequence, wherein the first electrode layer extends out of the PPTC core material to form a first epitaxial electrode;

[0044] The PPTC substrate comprises a first conductive layer, a PPTC core plate and a second conductive layer which are arranged in sequence, wherein the first conductive layer and the second conductive layer do not extend out of the periphery of the PPTC core plate;

[0045] In the multi-layer surface-mounted PPTC component: the basic composite unit and the PPTC substrate are stacked, an electrode layer in each of the basic composite units and a conductive layer in each of the PPTC substrates are electrically connected to each other and partially exposed to form a first welding pad, another electrode layer in each of the basic composite units and another conductive layer in each of the PPTC substrates are electrically connected to each other and partially exposed to form a second welding pad; the multi-layer surface-mounted PPTC component has both the first welding pad and the second welding pad on at least one outer surface.

[0046] Optionally, the multi-layer surface-mounted PPTC component has a first outer surface and a second outer surface that are arranged opposite to each other; the electrode layer and the conductive layer between adjacent PPTC core materials and PPTC core boards are electrically connected.

[0047] Optionally, the basic composite unit adopts a first basic composite unit, the second electrode layer of the first basic composite unit includes a second epitaxial electrode extending relative to the PPTC core material, and the second epitaxial electrode and the first epitaxial electrode are located on opposite sides of the PPTC core material;

[0048] The first basic composite units and the PPTC substrates are alternately arranged, each of the first electrode layers is electrically connected to each of the first conductive layers, and each of the second electrode layers is electrically connected to each of the second conductive layers, wherein:

[0049] The first basic composite unit and the PPTC substrate have the same number, the first epitaxial electrode located on the first outer surface is bent to the second outer surface to form the first welding pad, and the second epitaxial electrode closest to the first outer surface is bent to the second outer surface to form the second welding pad; or,

[0050] The first basic composite unit and the PPTC substrate have the same number, the first epitaxial electrode located on the first outer surface is bent to the second outer surface, the first electrode layer located on the first outer surface is partially exposed to form the first welding pad, and the second epitaxial electrode closest to the second outer surface is bent to the first outer surface to form the second welding pad; or,

[0051] The number of the basic composite unit is one more than that of the PPTC substrate, the first epitaxial electrode located at the first outer surface is bent to the second outer surface to form a first welding pad, the first electrode layer located at the first outer surface is partially exposed to form another first welding pad, the second epitaxial electrode located at the second outer surface is bent to the first outer surface to form the second welding pad, and the second electrode layer located at the second outer surface is partially exposed to form another second welding pad.

[0052] Optionally, the basic composite unit adopts a first basic composite unit and a second basic composite unit; the second electrode layer of the first basic composite unit includes a second epitaxial electrode extending relative to the PPTC core material, and the second epitaxial electrode and the first epitaxial electrode are located on opposite sides of the PPTC core material; in the second basic composite unit, the second electrode layer does not extend beyond the periphery of the PPTC core material.

[0053] A method for preparing a single-layer surface-mount PPTC component as described in any one of the above items, characterized in that the preparation method comprises the following steps:

[0054] A1. Prepare PPTC core material;

[0055] A2, compounding electrode foils on the upper and lower surfaces of the PPTC core material to form a first electrode layer and a second electrode layer, and then irradiating and cross-linking by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, to obtain the basic composite unit;

[0056] A3. Coating insulating material on the inner side of the epitaxial electrode and the surface of the electrode layer located on the surface layer, bending the first epitaxial electrode of the basic composite unit to form the first welding pad, and partially exposing the second electrode layer to form a second welding pad.

[0057] A method for preparing a multi-layer surface mounted PPTC component, characterized in that the preparation method comprises the following steps:

[0058] A1. Prepare PPTC core material;

[0059] A2, compounding electrode foils on the upper and lower surfaces of the PPTC core material to form a first electrode layer and a second electrode layer, and then irradiating and cross-linking by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, to obtain the basic composite unit;

[0060] A3. Coat insulating material on the inner side of the epitaxial electrode and the surface of the electrode layer located on the surface layer, stack a plurality of basic composite units, connect the epitaxial electrodes located on the same side of the stacked basic composite units, and form a first welding pad and a second welding pad on the outer surface of the stacked structure.

[0061] A method for preparing a multi-layer surface mounted PPTC component, characterized in that the preparation method comprises the following steps:

[0062] A1. Prepare PPTC core material;

[0063] A2, compounding electrode foils on the upper and lower surfaces of the PPTC core material to form a first electrode layer and a second electrode layer, and then irradiating and cross-linking by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, to obtain the basic composite unit;

[0064] A3. Coat insulating material on the inner side of the epitaxial electrode and on the surface of the electrode layer located on the surface layer, apply solder paste to the basic composite unit and the PPTC substrate and stack them, connect the epitaxial electrodes of each basic composite unit located on the same side after stacking, and form a first welding pad and a second welding pad on the outer surface of the stacked structure.

[0065] The present invention has at least the following beneficial effects:

[0066] The single-layer surface-mount PPTC component and the multi-layer surface-mount PPTC component provided by the present invention do not need to be produced using complex PCB processing technology, and the process from "etching insulating grooves on the upper metal foil 30 and the lower metal foil 20 respectively" to copper plating the first conductive through hole and the second conductive through hole is omitted. Instead, a process of bending the epitaxial electrode and coating or covering the insulating material at the position where insulation isolation is required is adopted. Obviously, the production process of the surface-mount PPTC component of the present invention is simpler than the PCB processing technology, and the production cost is low. In addition, since there is no constraint on the precise positioning of the graphics in the production of the multi-layer structure, the production of multi-layer surface-mount PPTC components with more than three layers becomes possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The technical features and advantages of the present invention will be more fully understood by referring to the following detailed description in conjunction with the accompanying drawings.

[0068] Figure 1 It is a cross-sectional view of a PPTC substrate in the prior art.

[0069] Figure 2 It is a cross-sectional view of a single-layer surface-mount PPTC component in the prior art.

[0070] Figure 3 It is a cross-sectional view of the basic composite unit of Example 1 of the present invention from one perspective.

[0071] Figure 4 This is a cross-sectional view of a basic composite unit according to Embodiment 2 of the present invention.

[0072] Figure 5 This is a cross-sectional view of a single-layer surface mount PPTC component according to Embodiment 3 of the present invention.

[0073] Figure 6 This is a cross-sectional view of a single-layer surface mount PPTC component according to Embodiment 4 of the present invention.

[0074] Figure 7 This is a cross-sectional view of a single-layer surface mount PPTC component according to an embodiment of the present invention.

[0075] Figure 8 This is a cross-sectional view of a double-layer surface mount PPTC component according to Embodiment 5 of the present invention.

[0076] Fig. 9 This is a cross-sectional view of a double-layer surface mount PPTC component according to an embodiment of the present invention.

[0077] Fig.10 This is a cross-sectional view of a double-layer surface mount PPTC component according to Embodiment 6 of the present invention.

[0078] Fig.11 This is a cross-sectional view of a double-layer surface mount PPTC component according to Embodiment 7 of the present invention.

[0079] Fig.12 This is a cross-sectional view of a three-layer surface mount PPTC component according to Embodiment 8 of the present invention.

[0080] Fig.13 This is a cross-sectional view of a five-layer surface mount PPTC component according to Embodiment 9 of the present invention.

[0081] Fig.14 This is a simplified structural diagram of a double-layer surface-mount PPTC component according to embodiment 10 of the present invention.

[0082] Fig.15 This is a simplified structural diagram of a double-layer surface-mount PPTC component according to embodiment 11 of the present invention.

[0083] Fig.16 This is a simplified structural diagram of a three-layer surface-mount PPTC component according to embodiment 12 of the present invention.

[0084] Fig.17 This is a simplified structural diagram of a three-layer surface mounted PPTC component according to embodiment 13 of the present invention.

[0085] Fig.18 This is a simplified structural diagram of a four-layer surface-mount PPTC component of Example 14.

[0086] Fig.19 This is a simplified structural diagram of a four-layer surface-mount PPTC component according to embodiment 15 of the present invention.

[0087] Fig. 20 This is a simplified structural diagram of a five-layer surface-mount PPTC component according to embodiment 16 of the present invention.

[0088] Fig.21 This is a simplified structural diagram of a five-layer surface-mount PPTC component according to embodiment 17 of the present invention.

[0089] Reference numerals:

[0090] The present invention:

[0091] 10. Basic composite unit; 101. First basic composite unit; 102. Second basic composite unit; 20. PPTC substrate;

[0092] 1. PPTC core material; 11. first surface; 12. second surface; 13. first side surface; 14. second side surface;

[0093] 2. first electrode layer; 21. first epitaxial electrode; 22. first pad; 24. first conductive portion; 25. first composite portion; 26. first reserved pad; 27. first welding pad; 28. first reserved welding pad;

[0094] 3. second electrode layer; 31. second epitaxial electrode; 32. second pad; 34. second conductive portion; 35. second composite portion; 36. second reserved pad; 37. second welding pad; 38. second reserved welding pad;

[0095] 41. first insulating layer; 42. second insulating layer; 43. third insulating layer; 44. fourth insulating layer; 45. first covering layer; 46. second covering layer;

[0096] 51. first insulating portion; 52. second insulating portion; 53. third insulating portion; 54. fourth insulating portion;

[0097] 61. first conductive layer; 62. second conductive layer; 63. PPTC core board;

[0098] 71. a first outer surface; 72. a second outer surface;

[0099] 8. Solder paste.

[0100] Existing technology:

[0101] 100, PPTC core material; 200, first conductive layer; 300, second conductive layer; 400, upper insulating layer; 500, lower insulating layer; 6001, upper first terminal electrode; 6002, lower first terminal electrode; 6003, upper second terminal electrode; 6004, lower second terminal electrode; 7001, first conductive through hole; 7002, second conductive through hole. DETAILED DESCRIPTION

[0102] Unless otherwise defined, technical or scientific terms used in the present specification and claims shall have the common meanings understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0103] In addition, the "soldering pad" and "welding pad" involved in the present invention are essentially the same concept. The "soldering pad" is used in the single-layer surface-mount PPTC component, and the "welding pad" is used in the multi-layer surface-mount PPTC component, so as to facilitate intuitive and clear expression of each embodiment.

[0104] In addition, the first reserved solder pad involved in the present invention is the first solder pad, the second reserved solder pad is the second solder pad, the first reserved welding pad is the first welding pad, and the second reserved welding pad is the second welding pad. The following distinction is made in name for the convenience of expression. The solder pad formed using the epitaxial electrode is directly called the first solder pad, the second solder pad, the first welding pad and the second welding pad, and the solder pad provided on the composite part is defined as the first reserved solder pad, the second reserved solder pad, the first reserved welding pad and the second reserved welding pad.

[0105] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0106] In addition, the welding technology involved in the following description adopts the method of first applying solder paste for initial positioning. After all the solder paste positioning is completed, the solder paste is melted to achieve welding fixation. The solder paste is used to indicate the welding position in the accompanying drawings. Considering that solder paste is an existing mature technology and solder paste is not the focus of the present invention, the following description uniformly labels the places where solder paste is applied, and does not set different marks for each solder paste.

[0107] Before describing the specific embodiments, the invention structure and method of the present invention are described as a whole in combination with the technical purpose and design concept of the present invention. Figure 1 and Figures 3 to 21 To understand.

[0108] The present invention aims to propose a technical solution that can reduce the production cost of PPTC components and improve the production efficiency of PPTC components by changing the complexity of the production process of surface-mount PPTC components. When solving such problems, the prior art generally improves the formula of the PPTC core material 1 and the connection process of the PPTC substrate 20 and the electrode plate (or lead). The present invention breaks the understanding of the traditional structure of the PPTC component, puts aside the constraints of the existing PPTC component production process and production equipment on people's thinking, and thinks from the production source of the PPTC component. A basic composite unit 10 (hereinafter referred to as "basic composite unit 10") that can be used in PPTC components is proposed in a breakthrough manner. Based on the technical concept of the composite basic composite unit 10, a single-layer surface-mount PPTC component made on the basis of the basic composite unit 10, a multi-layer surface-mount PPTC component made on the basis of the basic composite unit 10 and the PPTC substrate 20, and a multi-layer surface-mount PPTC component made on the basis of several basic composite units 10 are further proposed.

[0109] refer to Figure 3 The basic composite unit 10 includes a PPTC core material 1 and a plurality of electrode layers, wherein the plurality of electrode layers include a first electrode layer 2 and a second electrode layer 3. The PPTC core material 1 may be in the form of a thin sheet, having a first surface 11 and a second surface 12 opposite to each other. The "thickness direction" referred to in the present invention is a direction perpendicular to the first surface 11 and the second surface 12, i.e., Figure 3 Based on the up and down direction.

[0110] The electrode layer includes a composite part for connecting with the PPTC core material 1, for example, the first electrode layer 2 has a first composite part 25, and the second electrode layer 3 has a second composite part 35. The composite part is attached to the PPTC core material 1. The first composite part 25 of the first electrode layer 2 is attached to the first surface 11 of the PPTC core material 1, and the second composite part 35 of the second electrode layer 3 is attached to the second surface 12 of the PPTC core material 1. The PPTC core material 1, the first composite part 25 and the second composite part 35 are compositely formed, and the composite forming process can adopt the existing technology, such as hot pressing by a hot press. The first electrode layer 2 and / or the second electrode layer 3 extend out of the PPTC core material 1 to form an epitaxial electrode, that is, the basic composite unit 10 has at least one epitaxial electrode; the "extending out of the PPTC core material 1" and similar expressions involved in the present invention can be understood as the electrode layer extending out of the first surface 11 (or the second surface 12), and can also be understood as protruding from the side of the PPTC core material 1 (the surface between the first surface 11 and the second surface 12). For the present invention, these two understandings are essentially the same.

[0111] The epitaxial electrode can be formed in the process of compounding the first electrode layer 2, the second electrode layer 3 and the PPTC core material 1, that is, the first electrode layer 2 and / or the second electrode layer 3 are extended out of the PPTC core material 1 during compounding. The epitaxial electrode can be directly used as an electrode for connecting components outside the basic composite unit 10, or can be used as an electrode for connecting components outside the basic composite unit 10 after being processed (such as bending, folding, welding, cutting or other operations).

[0112] The basic composite unit 10 can be used to make various types of PPTC components. The present invention focuses on its application in single-layer surface-mounted PPTC components and multi-layer surface-mounted PPTC components. For single-layer surface-mounted PPTC components, the first electrode layer 2 of the basic composite unit 10 is partially exposed to form one or more pads, and the second electrode layer 3 is partially exposed to form one or more pads. For example, a basic composite unit 10 with two epitaxial electrodes is selected, and the two epitaxial electrodes are processed to form two pads; for another example, a basic composite unit 10 with one epitaxial electrode is selected, and the epitaxial electrode is processed to form a pad, and another pad is formed on the composite part of the electrode layer without the epitaxial electrode, so that the first electrode layer 2 and the second electrode layer 3 both form pads.

[0113] For a multilayer surface-mount PPTC component made on the basis of the basic composite unit 10 and the PPTC substrate 20, the basic composite unit 10 may adopt a first basic composite unit 101 having two oppositely arranged epitaxial electrodes, or a second basic composite unit 102 having one epitaxial electrode, or part of the first basic composite unit 101 and part of the second basic composite unit 102. The PPTC substrate 20 may adopt a first basic composite unit 101 having two oppositely arranged epitaxial electrodes, or a second basic composite unit 102 having one epitaxial electrode. Figure 1In the structure shown, the basic composite unit 10 and the PPTC substrate 20 are stacked and arranged in parallel. The basic composite unit 10 and the PPTC substrate 20 can be arranged alternately or in a non-alternating form. When the basic composite unit 10 and the PPTC substrate 20 are arranged alternately, the multi-layer surface-mounted PPTC component can be an odd number of layers, in which case the number of basic composite units 10 is one more than the number of PPTC substrates 20, or an even number of layers, in which case the number of basic composite units 10 is the same as the number of PPTC substrates 20.

[0114] For a multilayer surface-mount PPTC component made on the basis of a plurality of basic composite units 10, no matter it is made of a plurality of first basic composite units 101, a plurality of second basic composite units 102, or both of these basic composite units 10, as long as a plurality of basic composite units 10 are stacked, one of the first electrode layer 2 and the second electrode layer 3 of each basic composite unit 10 is electrically connected to each other to form a first welding pad 27, another of the first electrode layer 2 and the second electrode layer 3 of each basic composite unit 10 is electrically connected to each other to form a second welding pad 37, and the electrode layer corresponding to the first welding pad 27 is electrically isolated from the electrode layer corresponding to the second welding pad 37, the multilayer surface-mount PPTC component can be connected to the circuit through the first welding pad 27 and the second welding pad 37.

[0115] The above overall description is given to the structural part of the invention, and the following overall description is given to the method part of the invention.

[0116] The PPTC core material 1 used in the present invention has a positive temperature coefficient effect, and is specifically composed of a mixture of a crystalline polymer material, an interface compatibilizer, a conductive filler and an auxiliary filler.

[0117] The volume fraction of the crystalline polymer material in the conductive composite material base layer is between 10% and 85%, for example, the volume fraction is 10%, 47% or 85%. The crystalline polymer material is selected from one or a mixture of two or more of polyethylene, polyvinyl chloride, polystyrene, polycarbonate, polyvinyl fluoride, maleic anhydride grafted polyethylene, polypropylene, polyvinylidene fluoride, ethylene-vinyl acetate copolymer, polymethyl methacrylate, and ethylene-acrylic acid copolymer.

[0118] The conductive filler is selected from one or a mixture of two or more of carbon black, carbon nanotubes, carbon fibers, metal powders or conductive ceramic powders. The volume resistivity of the conductive filler used is lower than 200μΩ.cm, and the particle size is less than 30μm, and more preferably the particle size is not greater than 20μm. The average particle size of the carbon black is 20nm-120nm; the particle size of the metal powder is between 0.1um-20um, and is selected from one or more of nickel powder, copper powder, and silver powder; the particle size of the conductive ceramic powder is between 0.1um-50um, and the conductive ceramic powder is oxygen-free conductive ceramic powder, and is selected from one or more of titanium carbide, tungsten carbide, zirconium carbide, vanadium carbide, titanium boride, and titanium nitride.

[0119] The interfacial compatibilizer is a maleic anhydride grafted olefin polymer, specifically selected from one of maleic anhydride grafted high-density polyethylene, maleic anhydride grafted low-density polyethylene and maleic anhydride grafted linear low-density polyethylene.

[0120] The auxiliary filler is selected from one or more of calcium oxide, zinc oxide, magnesium oxide, aluminum oxide, silicon dioxide, calcium carbonate, magnesium hydroxide, and aluminum hydroxide.

[0121] The PPTC core material 1 can be prepared by the method described in the existing literature (for example, the method disclosed in Chinese patents CN102522173B and CN104319042A), or can be prepared by the following method:

[0122] The crystalline polymer, interfacial compatibilizer, conductive filler and auxiliary filler are weighed according to a certain mass ratio, and then mixed and granulated using a suitable mixing equipment such as an internal mixer, a twin-screw extruder, or a reciprocating single-screw extruder to obtain a PPTC compound;

[0123] The above PPTC compound is added into a single screw extruder calendering unit, and a PPTC core material 1 having a thickness of 0.05 mm to 2.0 mm and a width of 1 mm to 150 mm is prepared by calendering.

[0124] The preparation method of the basic composite unit 10 described in the present invention is as follows (the part involving the structure is referred to as Figure 3 ):

[0125] The PPTC core material 1 is prepared by the above method or the prior art;

[0126] Electrode foils are respectively composited on the upper and lower surfaces of the PPTC core material 1 to form a first electrode layer 2 and a second electrode layer 3, and then irradiated and cross-linked by electron beam or cobalt 60 with an irradiation dose of 1 Mrads to 100 Mrads to obtain the basic composite unit 10.

[0127] In a specific embodiment, the electrode foil is a metal foil or a metal alloy foil.

[0128] In a specific embodiment, the electrode foil is a copper foil, or a nickel-plated copper foil. The nickel-plated copper foil is a copper foil having a layer of nickel plated on a roughened surface or both surfaces; the roughened surface is the surface that is bonded to the PPTC core material 1 .

[0129] In a specific embodiment, the preparation method of the basic composite unit 10 is:

[0130] 1) According to the mass ratio, weigh 60.5% of high-density polyethylene (HDPE, HD5502FA, density 0.955g / cm 3 , Shanghai Secco Petrochemical Co., Ltd.), 2.5% maleic acid grafted polyethylene (Grafted-PE, Fusabond E100, Dow Chemical), 37.0% carbon black (VXC72, Cabot), and then extruded and granulated using a twin-screw extruder to obtain a PPTC compound;

[0131] 2) adding the above PPTC compound to a single screw extruder calendering unit, and preparing a PPTC core material 1 with a thickness of 0.5 mm and a width of 10 mm by calendering;

[0132] 3) Compounding copper foils of corresponding sizes on the upper and lower surfaces of the PPTC core material 1 according to specific structural requirements forms a first electrode layer 2 and a second electrode layer 3;

[0133] 4) The structure formed in step 3) is cross-linked by electron beam irradiation, with an irradiation dose of 50 Mrads, to obtain a basic composite unit 10.

[0134] The preparation method of the single-layer surface-mount PPTC component provided in the embodiment of the present invention is as follows (the part involving the structure is referred to as Figures 5 to 7 ):

[0135] The basic composite unit 10 is prepared by the above method;

[0136] According to the structural design of the single-layer surface-mounted PPTC component, an insulating material is coated on the inner side of the epitaxial electrode to be bent and on the surface of the electrode layer located on the surface to form an insulating portion, and according to the structural design requirements, an insulating material can also be coated on the side of the PPTC core material to form an insulating portion; and further according to the structural design, the portion where the electrode layers are stacked after bending is connected by welding to form two stacked electrode layers (for example Figure 7 The second epitaxial electrode 31 in the semiconductor device is folded outward and stacked on the second composite part 35 to form a second welding pad 32. At this time, the second epitaxial electrode 31 and the stacked part of the second composite part 35 need to be connected by welding), and then cut into the required size, thereby preparing the single-layer surface-mount PPTC component.

[0137] The welding method includes but is not limited to welding using solder paste.

[0138] In a specific embodiment, Figure 5 As shown, an insulating material is coated on the inner side of the first epitaxial electrode 21 and the second epitaxial electrode 31 of the basic composite unit 10, and an insulating material is coated on all or part of the outer surfaces of the first composite part 25 and the second composite part 35. When partially coated, the first reserved pad 26 and / or the second reserved pad 36 can be formed on the exposed first composite part 25 and / or the second composite part 35 that are not coated with the insulating material.

[0139] In a specific embodiment, Figure 6 As shown, an insulating material is coated on the inner side of the first epitaxial electrode 21 of the basic composite unit 10, and an insulating material is coated on the outer surface of the first composite part 25 and the second side surface 14, and an insulating material is coated on a part of the outer surface of the second composite part 35, so that the second composite part 35 is partially exposed to form a second pad 32.

[0140] In a specific embodiment, Figure 7 As shown, an insulating material is coated on the inner side of the first epitaxial electrode 21 of the basic composite unit 10, and an insulating material is coated on the outer surface of the first composite part 25 and the second side surface 14, and an insulating material is coated on a part of the outer surface of the second composite part 35. The inner side of the second epitaxial electrode 31 is not coated with an insulating material, and it is bent outward and stacked on the second composite part 35 that is not coated with the insulating material. The second epitaxial electrode 31 and the second composite part 35 are soldered with solder paste to form a second pad 32.

[0141] The preparation method of the multi-layer surface mount PPTC component made of several basic composite units 10 in the present invention is as follows (the part involving the structure is referred to as Figures 8 to 13 ):

[0142] The basic composite unit 10 is prepared by the above method;

[0143] According to the structural design of the multi-layer surface-mounted PPTC component, an insulating material is coated on the inner and / or outer sides of the epitaxial electrode to be bent and the surface of the outermost electrode layer to form an insulating portion, and according to the structural design requirements, an insulating material can also be coated on the side of the PPTC core material to form an insulating portion; and further according to the structural design, the electrode layers of the two basic composite units 10 are connected by welding and / or bonded by the insulating portion formed by coating the insulating material, and then cut into the size, thereby preparing the multi-layer surface-mounted PPTC component. The welding method includes but is not limited to welding with solder paste.

[0144] In a specific embodiment, Figure 8and Fig. 9 As shown, when the multi-layer surface-mounted PPTC element is two stacked basic composite units 10, the entire outer surface of the second composite part 35 of the upper basic composite unit 10 and / or the first composite part 25 of the lower basic composite unit 10 is coated with an insulating material to form an insulating part; the outer surfaces of the first composite part 25 of the upper basic composite unit 10 and the second composite part 35 of the lower basic composite unit 10 are partially or completely coated with an insulating material to form an insulating part, and when the insulating material is partially coated, the part not coated with the insulating material forms the first reserved welding pad 28 and / or the second reserved welding pad 38; the insulating material is coated on the partial inner side of the first epitaxial electrode 21 of the upper basic composite unit 10 and the second epitaxial electrode 31 of the lower basic composite unit 10, and the entire inner side of the second epitaxial electrode 31 of the upper basic composite unit 10 and the first epitaxial electrode 21 of the lower basic composite unit 10 to form an insulating part, and according to the bonding requirements, the insulating material can also be coated on the first side 13 and the second side 14 of the two basic composite units 10 to form an insulating part. The stacked portion of the first epitaxial electrode 21 of the upper and lower base composite units 10 and the stacked portion of the second epitaxial electrode 31 of the upper and lower base composite units 10 are soldered using solder paste.

[0145] In a specific embodiment, Fig.10 As shown, when the multi-layer surface-mounted PPTC element is two stacked basic composite units 10, the outer surfaces of the second composite part 35 of the upper basic composite unit 10 and the first composite part 25 of the lower basic composite unit 10 are partially or completely coated with insulating material to form an insulating part. When the insulating material is partially coated, the part not coated with the insulating material can form a second reserved welding pad 38 and / or a second welding pad 37; the insulating material is coated on the entire inner side of the first epitaxial electrode 21 of the upper basic composite unit 10 and the first epitaxial electrode 21 of the lower basic composite unit 10, and on the partial inner side of the second epitaxial electrode 31 of the upper basic composite unit 10 to form an insulating part, and according to the bonding requirements, the insulating material can also be coated on the first side 13 and the second side 14 of the two basic composite units 10 to form an insulating part. Soldering is performed on the outer surfaces of the first composite part 25 of the upper basic composite unit 10 and the second composite part 35 of the lower basic composite unit 10 by means of solder paste, and there are at least two welding locations; soldering is performed on the overlapping portion of the second epitaxial electrode 31 of the upper basic composite unit 10 and the second epitaxial electrode 31 of the lower basic composite unit 10 by means of solder paste, and the overlapping portion forms a second welding pad 37.

[0146] In a specific embodiment, Fig.11As shown, when the multi-layer surface-mounted PPTC element is two stacked basic composite units 10, the outer surfaces of the second composite part 35 of the upper basic composite unit 10 and the first composite part 25 of the lower basic composite unit 10 are partially or completely coated with insulating material to form an insulating part. When the insulating material is partially coated, the part not coated with the insulating material can form a second reserved welding pad 38 and / or a second welding pad 37; the insulating material is coated on the partial inner side of the second epitaxial electrode 31 of the upper basic composite unit 10 and the entire inner side and part of the outer side of the first epitaxial electrode 21 of the lower basic composite unit 10 to form an insulating part, and according to the bonding requirements, the insulating material can also be coated on the first side 13 and the second side 14 of the two basic composite units 10 to form an insulating part. The outer surfaces of the first composite part 25 of the upper basic composite unit 10 and the second composite part 35 of the lower basic composite unit 10 are welded by solder paste, and there are at least two welding locations; the overlapping part of the second epitaxial electrode 31 of the upper basic composite unit 10 and the second epitaxial electrode 31 of the lower basic composite unit 10 is welded by solder paste, and the overlapping part forms a second welding pad 37.

[0147] In a specific embodiment, Fig.12 and Fig.13 As shown, when the multi-layer surface mount PPTC element is composed of three to five stacked basic composite units 10, the outer surfaces of the first composite part 25 of the upper basic composite unit 10 and the second composite part 35 of the lower basic composite unit 10 are partially or completely coated with insulating materials to form insulating parts. When partially coated with insulating materials, the part not coated with insulating materials can form the first reserved welding pad 28 and / or the second reserved welding pad 38; the first epitaxial electrode 21 and the second epitaxial electrode 31 of each basic composite unit 10 are partially and / or completely coated with insulating materials to form insulating parts, and according to the bonding requirements, the first side surface 13 and the second side surface 14 of each basic composite unit 10 can also be coated with insulating materials to form insulating parts. Between the adjacent electrode parts of each basic composite unit 10 (such as Fig.12 Between the second composite part 35 of the upper layer basic composite unit 10 and the second composite part 35 of the middle layer basic composite unit 10, and between the second composite part 25 of the middle layer basic composite unit 10 and the first composite part 25 of the lower layer basic composite unit 10; Fig.13The second composite part 35 of the upper-middle basic composite unit 10 and the second composite part 35 of the first intermediate-layer basic composite unit 10, the second composite part 25 of the first intermediate-layer basic composite unit 10 and the first composite part 25 of the second intermediate-layer basic composite unit 10, the second composite part 35 of the second intermediate-layer basic composite unit 10 and the second composite part 35 of the third intermediate-layer basic composite unit 10, and the second composite part 25 of the third intermediate-layer basic composite unit 10 and the first composite part 25 of the lower-layer basic composite unit 10) are welded by solder paste, and there are at least two welding locations between every two adjacent electrolytic parts; the portion where the first epitaxial electrode 21 of the upper-layer basic composite unit 10 and the first epitaxial electrode 21 of the other-layer basic composite unit 10 are overlapped is welded by solder paste, and the portion where the second epitaxial electrode 31 of the lower-layer basic composite unit 10 and the second epitaxial electrode 31 of the other-layer basic composite unit 10 are overlapped is welded by solder paste.

[0148] In a specific embodiment, the PPTC core materials 1 of the multiple basic composite units 10 can be PPTC core materials 1 prepared with the same formula and the same thickness, or PPTC core materials 1 prepared with different formulas and the same thickness, or PPTC core materials 1 prepared with different formulas and different thicknesses.

[0149] The preparation method of the multilayer surface mount PPTC component made by the basic composite unit 10 and the PPTC substrate 20 in the present invention is as follows (the part involving the structure is referred to as Figures 14 to 21 ):

[0150] The basic composite unit 10 is prepared by the above method; the PPTC substrate 20 is directly obtained or the PPTC substrate 20 is prepared by the concept of the above method for preparing the basic composite unit 10;

[0151] According to the structural design of the multi-layer surface-mounted PPTC element, insulating materials are coated on the entire inner side and / or part of the inner side of the epitaxial electrode to be bent, and the entire and / or part of the surface of the outermost electrode layer. According to the structural design requirements, insulating materials can also be coated on the side of the PPTC core material 1 and / or the PPTC core plate 63 to form an insulating portion. Further, according to the structural design, the electrode layers of the basic composite units 10 and the PPTC substrate 20 stacked in sequence are connected by welding (for example, Fig.14 In the embodiment, soldering is performed between the second composite part 35 of the basic composite unit 10 and the second conductive layer 62 of the PPTC substrate 20 by solder paste, and the soldering positions are at least 2); and as needed, the epitaxial electrode of the basic composite unit 10 and the conductive layer stacking part of the PPTC substrate 20 (for example Fig.14In the embodiment, the first epitaxial electrode 21 of the basic composite unit 10 and the first conductive layer 61 of the PPTC substrate 20 are stacked) and / or the epitaxial electrode of the basic composite unit 10 and the stacked epitaxial electrode of another basic composite unit 10 are soldered by solder paste. Then the multilayer surface mount PPTC component is prepared by cutting into the required size. The specific part and method of coating the insulating material and the welding part and method can refer to the preparation of the multilayer surface mount PPTC component formed based on multiple basic review units 10, which will not be repeated here.

[0152] In a specific embodiment, the PPTC core material 1 and the PPTC core plate 63 can be prepared with the same formula and have the same thickness, or can be prepared with different formulas and have the same thickness, or can be prepared with different formulas and have different thicknesses.

[0153] In summary, the basic composite unit 10 and the products made using the basic composite unit 10 have at least the following advantages:

[0154] (1) The first electrode layer 2 and the second electrode layer 3 are composited on the surface layer of the PPTC core material 1 to form an epitaxial electrode on the electrode layer. After the basic composite unit 10 is applied to the PPTC component, the soldering pad (or welding pad) of the PPTC component can be formed by bending the epitaxial electrode and reserving an exposed area on the outermost conductive layer. The basic composite unit 10 and the surface-mounted PPTC component using the basic composite unit 10 omit the process from etching to copper plating on the hole, thereby simplifying the production process of the surface-mounted PPTC component, thereby improving production efficiency and reducing production costs.

[0155] (2) The structural improvement of the basic composite unit 10 is not aimed at improving the existing PPTC substrate 20, electrodes (or leads) and the processes of the two, but proposes a design concept different from the existing PPTC substrate 20 and electrodes (or leads). The structural improvement causes changes in the production process and production equipment of the surface-mounted PPTC components. In other words, the technical concept of the present invention is a subversion of the traditional process route.

[0156] (3) The present invention breaks the stereotype of people. On the one hand, as mentioned above, the present invention selects some intermediate products in the production process of surface mount PPTC components for improvement. For many years, people have been accustomed to making improvements based on existing processes and production equipment, and have never proposed to improve the intermediate products themselves. On the other hand, although the above-mentioned improvements are made to the initial intermediate products (i.e., the basic composite unit 10), they are based on a comprehensive and multi-angle systematic thinking of each process and equipment in the entire surface mount PPTC component production process to the final product structure, rather than single-point thinking and improvement. If any point in each link is stuck, the invention cannot be systematically completed.

[0157] (4) The basic composite unit 10 of the present invention is a huge commercial breakthrough. The basic composite unit 10 can be used in surface mount PPTC components, and surface mount PPTC components can be widely used in the battery industry, telecommunications and industrial equipment, automotive electronics and new energy vehicles, electronics industry, smart small appliances, security equipment and computer equipment. It can be seen that the commercial value of the basic composite unit 10 is huge.

[0158] Based on the above concept, the basic composite unit 10 has multiple specific variations, such as the first basic composite unit 101 and the second basic composite unit 102, which will be further described below with reference to the accompanying drawings.

[0159] Example 1

[0160] refer to Figure 3 In the first basic composite unit 101 provided in this embodiment, the first electrode layer 2 extends relative to the first side surface 13 of the PPTC core material 1 to form a first epitaxial electrode 21, and the second electrode layer 3 extends relative to the second side surface 14 of the PPTC core material 1 to form a second epitaxial electrode 31, and the second side surface 14 and the first side surface 13 are arranged opposite to each other.

[0161] In this embodiment, the end of the first electrode layer 2 opposite to the first epitaxial electrode 21 is flush with the PPTC core material 1. In other embodiments, as an alternative, the end of the first electrode layer 2 opposite to the first epitaxial electrode 21 may also be slightly narrower than the PPTC core material 1.

[0162] Of course, the edge positions of the first electrode layer 2 except the first epitaxial electrode 21 can be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1 .

[0163] In this embodiment, the thickness of the first electrode layer 2 is within 8.0 μm to 100 μm, for example, 8.0 μm, 45 μm or 100 μm. The volume resistivity of the first electrode layer 2 is lower than 10 μΩ.cm. The first electrode layer 2 has a roughened surface on one side thereof that is bonded to the PPTC core material 1 to improve the bonding strength between the two. The first electrode layer 2 has a nickel plating layer on its roughened surface or both sides. The first electrode layer 2 can be an electrode foil, the substrate of the electrode foil is a metal or a metal alloy, and in this embodiment, the first electrode layer 2 is selected from one of an electrolytic copper foil and a rolled copper foil.

[0164] In this embodiment, one end of the second electrode layer 3 corresponding to the first side surface 13 is flush with the PPTC core material 1 . In other embodiments, this position of the second electrode layer 3 may also be slightly narrower than the PPTC core material 1 .

[0165] Of course, the edge positions of the second electrode layer 3 except the second epitaxial electrode 31 can be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1 .

[0166] In this embodiment, the thickness of the second electrode layer 3 is within 8.0 μm to 100 μm, for example, 8.0 μm, 45 μm or 100 μm. The volume resistivity of the second electrode layer 3 is lower than 10 μΩ.cm. The side of the second electrode layer 3 that is bonded to the PPTC core material 1 is a roughened surface to improve the bonding strength between the two. The second electrode layer 3 has a nickel plating layer on its roughened surface or both sides. The second electrode layer 3 can be an electrode foil, and the substrate of the electrode foil is a metal or a metal alloy. In this embodiment, the second electrode layer 3 is selected from any one of electrolytic copper foil and rolled copper foil.

[0167] Example 2

[0168] refer to Figure 4 The difference between the second basic composite unit 102 provided in this embodiment and that provided in Embodiment 1 is that the second basic composite unit 102 in this embodiment does not include the second epitaxial electrode 31. In order to more clearly reflect the technical solution of this embodiment, the following is combined with Figure 4 Detailed description.

[0169] In the second basic composite unit 102 provided in this embodiment, the first electrode layer 2 extends relative to the first side surface 13 of the PPTC core material 1 to form a first epitaxial electrode 21, and the end of the first electrode layer 2 opposite to the first epitaxial electrode 21 is flush with the PPTC core material 1. In other embodiments, as an alternative, the end of the first electrode layer 2 opposite to the first epitaxial electrode 21 may also be slightly narrower than the PPTC core material 1. Of course, the edge positions of the first electrode layer 2 except the first epitaxial electrode 21 may be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1.

[0170] In this embodiment, the thickness of the first electrode layer 2 is within 8.0 μm to 100 μm, for example, 8.0 μm, 45 μm or 100 μm. The volume resistivity of the first electrode layer 2 is lower than 10 μΩ.cm. The first electrode layer 2 has a roughened surface on one side thereof that is bonded to the PPTC core material 1 to improve the bonding strength between the two. The first electrode layer 2 has a nickel plating layer on its roughened surface or both sides. The first electrode layer 2 can be an electrode foil, the substrate of the electrode foil is a metal or a metal alloy, and in this embodiment, the first electrode layer 2 is selected from one of an electrolytic copper foil and a rolled copper foil.

[0171] In this embodiment, the end of the second electrode layer 3 on the same side as the first epitaxial electrode 21 is flush with the PPTC core material 1, and the end opposite to the first epitaxial electrode 21 is also flush with the PPTC core material 1. In other embodiments, these two positions of the second electrode layer 3 may also be slightly narrower than the PPTC core material 1. Of course, the entire periphery of the second electrode layer 3 may also be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1.

[0172] In this embodiment, the thickness of the second electrode layer 3 is within 8.0 μm to 100 μm, for example, 8.0 μm, 45 μm or 100 μm. The volume resistivity of the second electrode layer 3 is lower than 10 μΩ.cm. The side of the second electrode layer 3 that is bonded to the PPTC core material 1 is a roughened surface to improve the bonding strength between the two. The second electrode layer 3 has a nickel plating layer on its roughened surface or both sides. The second electrode layer 3 can be an electrode foil, and the substrate of the electrode foil is a metal or a metal alloy. In this embodiment, the second electrode layer 3 is selected from any one of electrolytic copper foil and rolled copper foil.

[0173] It should be noted that Example 1 and Example 2 are only two illustrations, and the basic composite unit 10 of the present invention can also produce more deformations, as long as the first electrode layer, the PPTC core material and the second electrode layer are compositely formed and have at least one epitaxial electrode.

[0174] The present invention also provides an application of the basic composite unit 10 in a single-layer mounted PPTC component. Embodiments 3 and 4 provide two examples in conjunction with the accompanying drawings. Figures 3 to 7 The relationship between the basic composite unit 10 and the single-layer surface mount PPTC element will be described.

[0175] In one production process, the PPTC core material 1, the first electrode layer 2 and the second electrode layer 3 are compounded to form a long strip product, which is equivalent to a collection of several basic composite units 10, and a portion for forming an epitaxial electrode is reserved in the width direction of the product, that is, a basic composite unit 10 is obtained. The basic composite unit 10 is processed and then cut according to the required size (which can be achieved by punching, water jet cutting and cutting) to obtain a single-layer surface-mounted PPTC component, wherein the first electrode layer 2 and the second electrode layer 3 are used to form pads respectively, and the pads can be formed by epitaxial electrodes or by the first composite part 25 and the second composite part 35. Each electrode layer can correspond to one or more pads. In the single-layer surface-mounted PPTC component, at least one outer surface has the first pad and the second pad at the same time. Among all the pads, at least one pad can be formed by bending the epitaxial electrode to save processing costs. When the epitaxial electrode is bent, an isolation layer is set between the side close to the PPTC core material 1 and another electrode layer. The isolation layer is made of insulating material and is used to achieve electrical isolation between the epitaxial electrode and the side of the PPTC core material 1 or another electrode layer. The surface position other than the pad on the composite part can be partially or completely covered with an isolation layer made of insulating material to reduce the risk of short circuit when the single-layer surface-mounted PPTC component is connected to the circuit board.

[0176] The single-layer surface-mount PPTC component can be made by a first basic composite unit 101 having two oppositely arranged epitaxial electrodes (for example Figure 3 The basic composite unit 10 shown in FIG. 1 may also be made from a second basic composite unit 102 having only one epitaxial electrode (e.g. Figure 4 The basic composite unit 10 shown).

[0177] The two situations are described in detail below with reference to the accompanying drawings and specific embodiments.

[0178] Example 3

[0179] refer to Figure 5 This embodiment provides a single-layer surface-mount PPTC component, wherein any of the above basic composite units 10 (refer to Figure 3 ) based on the

[0180] The first epitaxial electrode 21 is processed into a structure having a first pad 22, and the second epitaxial electrode 31 is processed into a structure having a second pad 32. The first pad 22 and the second pad 32 can both be used as a portion of a single-layer SMD PPTC component connected to a soldering area on a circuit board.

[0181] The first pad 22 formed by the first epitaxial electrode 21 and the second pad 32 formed by the second epitaxial electrode 31 are located on two opposite surfaces of the single-layer surface-mounted PPTC component. The first epitaxial electrode 21 is continuously bent along the PPTC core material 1 to cover the end of the second electrode layer 3, that is, after the first epitaxial electrode 21 is bent inward along the first side surface 13 of the PPTC core material 1, it is further bent toward the direction close to the PPTC core material 1 to cover the second electrode layer 3, and the portion of the first epitaxial electrode 21 covering the end of the second electrode layer 3 is the first pad 22. A first isolation layer 41 is provided on one side of the first epitaxial electrode 21 facing the PPTC core material 1. The first isolation layer 41 is made of insulating material and is used to electrically isolate the first epitaxial electrode 21 from the side of the PPTC core material 1 and the second electrode layer 3. The first isolation layer 41 can be provided on the first epitaxial electrode 21 or the PPTC core material 1 and the second electrode layer 3 in the form of coating or pasting before the first epitaxial electrode 21 is bent. After the first epitaxial electrode 21 is bent, the first isolation layer 41 bonds and fixes the first epitaxial electrode 21 to the PPTC core material 1 and the second electrode layer 3.

[0182] The second epitaxial electrode 31 is continuously bent along the PPTC core material 1 until it covers the end of the first electrode layer 2, that is, after the second epitaxial electrode 31 is bent inward along the second side surface 14 of the PPTC core material 1, it is further bent toward the direction close to the PPTC core material 1 to cover the first electrode layer 2, and the portion of the second epitaxial electrode 31 covering the end of the first electrode layer 2 is the second pad 32. A second isolation layer 42 is provided on the side of the second epitaxial electrode 31 facing the PPTC core material 1. The second isolation layer 42 is made of insulating material and is used to electrically isolate the second epitaxial electrode 31 from the PPTC core material 1 and the first electrode layer 2, so that the second pad 32 is electrically isolated from the first electrode layer 2; the second isolation layer 42 can be provided on the second epitaxial electrode 31 or the PPTC core material 1 and the first electrode layer 2 in the form of coating or pasting before the second epitaxial electrode 31 is bent. After the second epitaxial electrode 31 is bent, the second isolation layer adheres and fixes the second epitaxial electrode 31 to the PPTC core material 1 and the first electrode layer 2.

[0183] The first composite part 25 is also provided with a first reserved pad 26, which is used as a spare pad. The first reserved pad 26 is located at one end of the first composite part 25, and is arranged opposite to the first pad 22. Of course, in other embodiments, the projection of the first reserved pad 26 along the thickness direction and the projection of the first pad 22 along the thickness direction are partially staggered or completely staggered, which is also within the protection scope of the present invention. During production, the first reserved pad 26 can be formed by exposing the preset area of ​​the first composite part 25. Insulating material is provided at a local position of the first composite part 25 to reduce the risk of short circuit when the single-layer surface-mount PPTC component is welded to the circuit board. Specifically in this embodiment, the surface between the first reserved pad 26 and the second pad 32 on the first composite part 25 is coated with a third isolation layer 43, and the third isolation layer 43 and the second isolation layer 42 that isolates the second pad 32 and the first composite part 25 are connected into one piece.

[0184] The second composite part 35 is also provided with a second reserved pad 36, which is used as a spare pad. The second reserved pad 36 is located at one end of the second composite part 35, and is arranged opposite to the second pad 32; of course, in other embodiments, the projection of the second reserved pad 36 along the thickness direction and the projection of the second pad 32 along the thickness direction are partially staggered or completely staggered, which is also within the protection scope of the present invention. During production, the second reserved pad 36 can be formed by exposing the preset area of ​​the second composite part 35. Insulating material is provided at a local position of the second composite part 35 to reduce the risk of short circuit when the single-layer surface-mount PPTC component is welded to the circuit board. Specifically in this embodiment, the surface of the second composite part 35 between the second reserved pad 36 and the first pad 22 is coated with a fourth isolation layer 44, and the fourth isolation layer 44 and the first isolation layer 41 that isolates the first pad 22 and the second composite part 35 are connected into one piece.

[0185] like Figure 5 As shown, in this embodiment, the first reserved pad 26 and the second reserved pad 36 are provided at the same time, and as an alternative, the solution of retaining only the first reserved pad 26 or the second reserved pad 36 is also within the protection scope of the present invention.

[0186] Example 4

[0187] refer to Figure 6 This embodiment provides a single-layer surface-mount PPTC component. In this embodiment, the basic composite unit 10 (refer to Figure 4 ) based on the

[0188] The single-layer surface-mounted PPTC component is provided with a first pad 22 and a second pad 32 on one side. The first epitaxial electrode 21 is continuously bent along the PPTC core material 1 to cover the end of the second electrode layer 3, that is, after the first epitaxial electrode 21 is bent inward along the first side surface 13 of the PPTC core material 1, it is further bent toward the direction close to the PPTC core material 1 to cover the second electrode layer 3, and the portion of the first epitaxial electrode 21 covering the end of the second electrode layer 3 is the first pad 22. A first isolation layer 41 is provided on one side of the first epitaxial electrode 21 facing the PPTC core material 1. The first isolation layer 41 is made of insulating material and is used to electrically isolate the first epitaxial electrode 21 from the side of the PPTC core material 1 and the second electrode layer 3. The first isolation layer 41 can be provided on the first epitaxial electrode 21 or the PPTC core material 1 and the second electrode layer 3 in the form of coating or pasting before the first epitaxial electrode 21 is bent. After the first epitaxial electrode 21 is bent, the first isolation layer 41 bonds and fixes the first epitaxial electrode 21 to the PPTC core material 1 and the second electrode layer 3.

[0189] The end of the second electrode layer 3 corresponding to the first side 13 does not extend out of the PPTC core material 1, and the end of the second electrode layer 3 corresponding to the second side 14 of the PPTC core material 1 does not extend out of the PPTC core material 1. Preferably, the periphery of the second electrode layer 3 evenly extends out of the PPTC core material 1, that is, the second electrode layer 3 is composed of the second composite part 35. The end of the second composite part 35 opposite to the first pad 22 is exposed to form the second pad 32. The area between the first pad 22 and the second pad 32 on the second electrode layer 3 is covered with a fourth isolation layer 44, which is made of insulating material and is connected to the first isolation layer 41 that isolates the first pad 22 and the second composite part 35.

[0190] In this embodiment, the side of the single-layer surface-mounted PPTC component corresponding to the second side 14 of the PPTC core material 1 is covered with a first covering layer 45 made of an insulating material, and the side of the first composite portion 25 facing away from the PPTC core material 1 is covered with a second covering layer 46 made of an insulating material, and the first covering layer 45 and the second covering layer 46 are connected as a whole. In this embodiment, the side of the first electrode layer 2 facing away from the first side 13 is not provided with an insulating material, and in other embodiments, this place may also be covered with an insulating material.

[0191] It should be noted that this embodiment adopts Figure 4 The basic composite unit 10 shown is made into a single-sided soldered (i.e., a first solder pad 22 and a second solder pad 32 are set on a single side) single-layer surface-mounted PPTC component. In other embodiments, as a replacement means, such as Figure 7 As shown, it is also possible to use Figure 3 The basic composite unit 10 shown is made into a single-sided soldered single-layer surface-mounted PPTC component, wherein the second epitaxial electrode 31 is folded and then coated with solder paste 8 for fixation.

[0192] The above describes the application of the basic composite unit 10 in a single-layer surface mount PPTC component. Next, the application of the basic composite unit 10 in a multi-layer surface mount PPTC component is described in conjunction with the accompanying drawings. The multi-layer surface mount PPTC component is made on the basis of the basic composite unit 10 provided in the above embodiment. For example, a plurality of basic composite units 10 are stacked and connected in parallel to form a multi-layer surface mount PPTC component. For example, the basic composite unit 10 and the existing PPTC substrate 20 (such as Figure 1 As shown in the figure, they are stacked and connected in parallel to form a multi-layer surface mounted PPTC component. Next, these two types of multi-layer surface mounted PPTC components are described respectively.

[0193] First, a multi-layer surface mount PPTC component formed by stacking and connecting a plurality of basic composite units 10 in parallel is described as a whole (which can be combined with Figure 3 to Figure 4 , Figures 8 to 13 Understanding), and then further illustrated by Examples 5 to 9.

[0194] In the multi-layer surface mount PPTC component, each basic composite unit 10 is stacked. One of the first electrode layer 2 and the second electrode layer 3 of each basic composite unit 10 is electrically connected to each other, and the electrode layer located at or near the outer surface is partially exposed to form a first welding pad 27. The other of the first electrode layer 2 and the second electrode layer 3 of each basic composite unit 10 is electrically connected to each other, and the electrode layer located at or near the outer surface is partially exposed to form a second welding pad 37. Each electrode layer corresponding to the first welding pad 27 is electrically isolated from each electrode layer corresponding to the second welding pad 37, and the electrical isolation can be achieved by providing an insulating material. The first welding pad 27 and the second welding pad 37 are located at two opposite outer surfaces of the multi-layer surface mount PPTC component. In the multi-layer surface mount PPTC component, at least one outer surface has both the first welding pad 27 and the second welding pad 37.

[0195] A variety of connection methods can be used between two adjacent basic composite units 10, such as bonding and welding. The main difference between these two fixing methods is whether the two electrode layers between the two adjacent PPTC core materials 1 are insulated or conductively connected. For ease of description, in the following overall description of the multi-layer surface-mount PPTC component, the two electrode layers are defined as the first connection layer and the second connection layer, respectively.

[0196] In the adhesive fixing method, a first insulating portion 51 (such as Figure 8 and Fig. 9) for insulation isolation, the first insulating portion 51 is bonded to the first connection layer and the second connection layer respectively. The welding pad corresponding to the first connection layer is different from the welding pad corresponding to the second connection layer, and both ends of the first insulating portion 51 can also extend to the side of the PPTC core material 1 to isolate the PPTC core material 1 and the epitaxial electrode.

[0197] In the welding fixing method, the first connection layer and the second connection layer are attached to each other and the two are welded and fixed (first apply solder paste 8 between the two, and then fix them by reflow soldering), and the first connection layer and the second connection layer correspond to the same welding pad.

[0198] In a specific embodiment, any adjacent basic composite units 10 can be connected by bonding or welding, or some adjacent basic composite units 10 can be bonded and fixed, while other adjacent basic composite units 10 can be welded and fixed, as long as the parallel connection of the PPTC core materials 1 can be achieved.

[0199] The multi-layer surface mount PPTC component can be formed by a plurality of first basic composite units 101 (such as Figure 3 The two electrode layers between adjacent PPTC core materials 1 are insulated, the first electrode layers 2 are electrically connected, the second electrode layers 3 are electrically connected, and the two epitaxial electrodes located on the outer surface of the multi-layer surface-mounted PPTC component are bent to the opposite side to form the first welding pad 27 and the second welding pad 37 located on the two outer surfaces. The multi-layer surface-mounted PPTC component can also be made of a plurality of second basic composite units 102 (such as Figure 4 The two electrode layers between adjacent PPTC core materials 1 are fixed by soldering with solder paste 8. The multi-layer surface mount PPTC component can also be made by one or more first basic composite units 101 and a second basic composite unit 102. The second basic composite unit 102 is located at one end of the multi-layer surface mount PPTC component.

[0200] In some embodiments, among the electrode layers corresponding to the first welding pad 27, at least one electrode layer forms a first conductive portion 24 extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the first conductive portion 24 of the electrode layer to form the first welding pad 27. Of course, in other embodiments, the first welding pad 27 is embodied in other ways (such as formed by a composite portion), which is also within the protection scope of the present invention.

[0201] In some embodiments, in each electrode layer corresponding to the second welding pad 37: at least one electrode layer forms a second conductive portion 34 extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the second conductive portion 34 of the electrode layer to form the second welding pad 37. Of course, in other embodiments, the second welding pad 37 is embodied in other ways and is also within the protection scope of the present invention.

[0202] In some embodiments, the multilayer surface mount PPTC component may further include a first reserved welding pad 28 formed by the electrode layer, which is used as a spare welding pad. The first reserved welding pad 28 is located on a side opposite to the first welding pad 27, and both can be arranged opposite to the first welding pad 27 in the thickness direction. Of course, in other embodiments, the projection of the first reserved welding pad 28 in the thickness direction and the projection of the first welding pad 27 in the thickness direction are partially staggered or completely staggered, which is also within the protection scope of the present invention.

[0203] In some embodiments, the multilayer surface mount PPTC component may further include a second reserved welding pad 38 formed by the electrode layer, which is used as a spare welding pad. The second reserved welding pad 38 is located on a side opposite to the second welding pad 37, and may be arranged directly opposite to the second welding pad 37. Of course, in other embodiments, the projection of the second reserved welding pad 38 in the thickness direction and the projection of the second welding pad 37 in the thickness direction are partially staggered or completely staggered, which is also within the protection scope of the present invention.

[0204] In some embodiments, the surface of the first composite part 25 or the surface of the second composite part 35 of the outermost electrode layer of the multi-layer surface-mounted PPTC element is partially covered with a third insulating part 53 made of an insulating material, and the third insulating part 53 can be provided on the composite part by coating. The side of the PPTC core material 1 can be provided with a second insulating part 52 made of an insulating material, which is used to electrically isolate the PPTC core material 1 and the conductive part (such as the first conductive part 24 or the second conductive part 34). When the second insulating part 52 is provided between the side of the PPTC core material 1 at the end and the epitaxial electrode, the third insulating part 53 and the second insulating part 52 can be connected into one piece.

[0205] In the multi-layer surface mount PPTC component, each PPTC core material 1 may have the same thickness, or at least one of the PPTC core materials 1 may have a thickness different from that of other PPTC core materials 1. Each PPTC core material 1 may have the same known material, or at least one of the PPTC core materials 1 may have a known material different from that of other PPTC core materials 1.

[0206] In specific applications, multi-layer surface-mounted PPTC components can produce many variations. The following examples of two-layer, three-layer and five-layer surface-mounted PPTC components are illustrated in conjunction with the accompanying drawings. Of course, according to the above description, the multi-layer surface-mounted PPTC component is not limited to the following embodiments, and can also be any multi-layer structure such as six layers, seven layers, etc.

[0207] Example 5

[0208] refer to Figure 8 This embodiment provides a double-layer surface-mount PPTC component, wherein two basic composite units 10 respectively adopt any of the above-mentioned first basic composite units 101 having a first epitaxial electrode 21 and a second epitaxial electrode 31, and accordingly, the two basic composite units 10 are stacked to form two first epitaxial electrodes 21 and two second epitaxial electrodes 31.

[0209] The two first epitaxial electrodes 21 are electrically connected to form a first welding pad 27. The first epitaxial electrode 21 located at the top is bent twice continuously to form a first conductive portion 24 and a first welding pad 27, and the first epitaxial electrode 21 located at the bottom is bent once to form a first conductive portion 24. The two first conductive portions 24 are arranged in close proximity and electrically connected, and the two are connected by soldering with solder paste 8. In other embodiments, as an alternative, such as Fig. 9 As shown, the first epitaxial electrode 21 located at the bottom can also be bent twice continuously to form a first conductive part 24 and a first welding pad 27, and the first epitaxial electrode 21 located at the top only forms a first conductive part 24. The two first conductive parts 24 are arranged in a close fit and are fixed by soldering with solder paste 8 to form an electrical connection relationship.

[0210] The two second epitaxial electrodes 31 are electrically connected to form a second welding pad 37. The second epitaxial electrode 31 at the bottom is bent twice to form a second conductive portion 34 and a second welding pad 37, and the second epitaxial electrode 31 at the top is bent once to form a second conductive portion 34. The two second conductive portions 34 are arranged in close proximity and electrically connected, and the two are connected by soldering with solder paste 8. In other embodiments, as an alternative, such as Fig. 9 As shown, the second epitaxial electrode 31 at the top may be bent twice continuously to form a second conductive portion 34 and a second welding pad 37, and the second epitaxial electrode 31 at the bottom may only form a second conductive portion 34, and the two second conductive portions 34 are arranged in close proximity and electrically connected.

[0211] The two basic composite units 10 are electrically isolated and fixed by the first insulating portion 51. One end of the first insulating portion 51 extends in the thickness direction to isolate the first epitaxial electrode 21 and the first side surface 13 of the PPTC core material 1 located above, and the other end of the first insulating portion 51 extends downward in the thickness direction to isolate the second epitaxial electrode 31 and the second side surface 14 of the PPTC core material 1 located below.

[0212] Figure 8 The upper outer surface is provided with a first reserved welding pad 28, and the lower outer surface is provided with a second reserved welding pad 38, which are used as spare welding pads. In other embodiments, as an alternative means, only one of the first reserved welding pad 28 and the second reserved welding pad 38 is provided, and this solution is also within the protection scope of the present invention. Figure 8 The third insulating portion 53 at the upper outer surface is connected to the second insulating portion 52 on the right side, and the third insulating portion 53 at the lower outer surface is connected to the second insulating portion 52 on the left side. When the first reserved welding pad 28 is not provided, the corresponding position can be covered by the third insulating portion 53. Similarly, when the second reserved welding pad 38 is not provided, the corresponding position can be covered by the third insulating portion 53.

[0213] Example 6

[0214] refer to Fig.10 This embodiment provides a double-layer surface-mount PPTC component, which is manufactured based on a first basic composite unit 101 and a second basic composite unit 102 . Accordingly, the two basic composite units 10 form two first epitaxial electrodes 21 and one second epitaxial electrode 31 .

[0215] The composite parts of the two first electrode layers 2 located between adjacent PPTC core materials 1 are bonded together and connected by solder paste 8. One first epitaxial electrode 21 is first bent upward and then bent toward the direction close to the PPTC core material 1 to form a first welding pad 27; the other first epitaxial electrode 21 is first bent downward and then bent toward the direction close to the PPTC core material 1 to form another first welding pad 27, that is, in this embodiment, two first welding pads 27 are formed by epitaxial electrodes.

[0216] The second epitaxial electrode 31 located on the upper outer surface of the double-layer SMD PPTC element is continuously bent and fixed with the composite part of the second electrode layer 3 located on the lower outer surface by solder paste 8 to form a second solder pad 37. A second insulating part 52 is provided between the second conductive part 34 formed by the second epitaxial electrode 31 and the side surface of the PPTC core material 1 for electrical isolation.

[0217] This embodiment is also provided with a second reserved welding pad 38, which is arranged opposite to the second welding pad 37. A third insulating portion 53 is provided between the second reserved welding pad 38 and the first welding pad 27 on the outer surface thereof for electrical isolation, and the third insulating portion 53 is connected to the second insulating portion 52 provided on the inner side of the first epitaxial electrode 21 bent upward as a whole. A third insulating portion 53 is also provided between the second welding pad 37 and the first welding pad 27 on the outer surface thereof for electrical isolation, and the third insulating portion 53 is connected to the second insulating portion 52 provided on the inner side of the first epitaxial electrode 21 bent downward as a whole.

[0218] Of course, without providing the second reserved solder pad 38, other technical solutions that are the same as those in this embodiment are also within the protection scope of the present invention.

[0219] Example 7

[0220] refer to Fig.11 This embodiment provides a double-layer surface-mount PPTC component, which is made of two second basic composite units 102 . Accordingly, the two second basic composite units 102 form two first epitaxial electrodes 21 .

[0221] The first epitaxial electrode 21 located on the upper outer surface of the double-layer surface-mounted PPTC element is continuously bent, attached to and welded to the second electrode layer 3 located on the lower outer surface to form a second welding pad 37 .

[0222] The second electrode layer 3 and the first electrode layer 2 located between the two PPTC core materials 1 are bonded and fixed by solder paste 8. The first epitaxial electrode 21 there is continuously bent to any outer surface of the double-layer surface-mounted PPTC component to form a first welding pad 27. In this embodiment, the first welding pad 27 and the second welding pad 37 are both located Fig.11 At the lower outer surface shown, in other embodiments, the solution of setting the first welding pad 27 on the upper outer surface and setting the second reserved welding pad 38 on the upper outer surface is also within the protection scope of the present invention.

[0223] like Fig.11 As shown, in this embodiment, a third insulating portion 53 is provided on the upper outer surface, and the side of the single-layer surface-mounted PPTC component is covered with a fourth insulating portion 54, and the fourth insulating portion 54 and the third insulating portion 53 are connected as one piece. The third insulating portion 53 between the second welding pad 37 and the first welding pad 27 is connected as one piece with the corresponding second insulating portion 52.

[0224] Example 8

[0225] refer to Fig.12This embodiment provides a three-layer surface-mount PPTC component, which is manufactured on the basis of three first basic composite units 101 . Accordingly, the three first basic composite units 101 have three first epitaxial electrodes 21 and three second epitaxial electrodes 31 .

[0226] Each first electrode layer 2 is electrically connected, and each second electrode layer 3 is electrically connected. Two adjacent basic composite units 10 are fixed by welding. Specifically, two of the first electrode layers 2 are fixed by solder paste 8, and each is bent in different directions to form two first conductive parts 24; another first electrode layer 2 is located at the upper outer surface of the three-layer surface-mounted PPTC component, and the corresponding first epitaxial electrode 21 is continuously bent to form a first welding pad 27 and fixed to the other two first conductive parts 24 by solder paste 8. Two of the second electrode layers 3 are fixed by solder paste 8, and each is bent in different directions to form two second conductive parts 34; another second electrode layer 3 is located at the lower outer surface of the three-layer surface-mounted PPTC component, and the corresponding second epitaxial electrode 31 is continuously bent to form a second welding pad 37 and fixed to the other two second conductive parts 34 by solder paste 8.

[0227] Fig.12 As shown, a first reserved welding pad 28 is provided on the upper outer surface, and a second reserved welding pad 38 is provided on the lower outer surface, which are used as spare welding pads. Fig.12 As shown, this embodiment has four second insulating parts 52, the two second insulating parts 52 on the left are used to isolate the first conductive part 24 and the PPTC core material 1, and the two second insulating parts 52 on the right are used to isolate the second conductive part 34 and the PPTC core material 1, wherein the third insulating part 53 on the upper outer surface and the second insulating part 52 on the upper right are connected as one piece, and the third insulating part 53 on the lower outer surface and the second insulating part 52 on the lower left are connected as one piece. Fig.12 As shown, the second insulating portion 52 partially located on the side of the PPTC is used to isolate the epitaxial electrode and the two PPTC core materials 1 and the electrode layer located between the two PPTC core materials 1 .

[0228] Example 9

[0229] refer to Fig.13 This embodiment provides a five-layer surface-mount PPTC component, which is manufactured on the basis of five first basic composite units 101 . Accordingly, the five first basic composite units 101 have five first epitaxial electrodes 21 and five second epitaxial electrodes 31 .

[0230] Each first electrode layer 2 is electrically connected, and each second electrode layer 3 is electrically connected. Two adjacent basic composite units 10 are fixed by welding. Specifically, the first electrode layers 2 located between adjacent PPTC core materials 1 can be bent to form a first conductive part 24, or one of them can be bent to form the first conductive part 24, and the other can be extended straight; the first electrode layer 2 located on the upper outer surface of the five-layer surface-mounted PPTC component, the corresponding first epitaxial electrode 21 is continuously bent to form the first welding pad 27 and fixed with the other first conductive part 24 by solder paste 8. The second electrode layer 3 located between adjacent PPTC core materials 1 can be bent to form a second conductive part 34, or one of them can be bent to form the second conductive part 34, and the other can be extended straight; the second electrode layer 3 located on the lower outer surface of the five-layer surface-mounted PPTC component, the corresponding second epitaxial electrode 31 is continuously bent to form the second welding pad 37 and fixed with the other second conductive part 34 by solder paste 8.

[0231] Fig.13 As shown, a first reserved welding pad 28 is provided at the upper outer surface, and a second reserved welding pad 38 is provided at the lower outer surface, which are used as spare welding pads. Fig.13 The third insulating portion 53 on the upper outer surface is connected to the second insulating portion 52 on the right side, and the third insulating portion 53 on the lower outer surface is connected to the second insulating portion 52 on the left side. Fig.13 As shown, the second insulating portion 52 partially located on the side of the PPTC is used to isolate the epitaxial electrode and the two PPTC core materials 1 and the electrode layer located between the two PPTC core materials 1 .

[0232] Next, the basic composite unit 10 and the existing PPTC substrate 20 (such as Figure 1 The multi-layer surface mount PPTC components formed by stacking and connecting in parallel are described as a whole (can be combined with Figure 3 , Figures 14 to 21 Understanding), and then further illustrated by Examples 10 to 19.

[0233] The PPTC substrate 20 includes a first conductive layer 61, a PPTC core plate 63, and a second conductive layer 62 which are arranged in sequence, and the first conductive layer 61 and the second conductive layer 62 do not extend out of the periphery of the PPTC core plate 63. The functions of the first conductive layer 61 and the second conductive layer 62 are the same as those of the first electrode layer 2 and the second electrode layer 3 in the basic composite unit 10, and each conductive layer and each electrode layer can also be made of the same material. The function of the PPTC core plate 63 is the same as that of the PPTC core material 1, and both can be made of the same material, that is, the manufacturing method of the PPTC core material 1 mentioned above is also applicable to the manufacturing of the PPTC core plate 63. In addition, the PPTC substrate 20 can adopt the same production process as the basic composite unit 10, except that when manufacturing the PPTC substrate 20, it is not necessary to reserve a portion for forming an epitaxial electrode.

[0234] In some embodiments, the basic composite unit 10 and the PPTC substrate 20 are alternately arranged in the thickness direction, an electrode layer in each basic composite unit 10 and a conductive layer in each PPTC substrate 20 are electrically connected to each other and partially exposed to form one or more first welding pads 27, another electrode layer in each basic composite unit 10 and another conductive layer in each PPTC substrate 20 are electrically connected to each other and partially exposed to form one or more second welding pads 37, so that the PPTC core material 1 and the PPTC core board 63 are connected in parallel. The electrode layer and the conductive layer corresponding to the first welding pad 27 are electrically isolated from the electrode layer and the conductive layer corresponding to the second welding pad 37. In the multi-layer surface-mounted PPTC component, at least one outer surface has both the first welding pad 27 and the second welding pad 37.

[0235] The multi-layer surface-mounted PPTC component has a first outer surface 71 and a second outer surface 72 that are arranged opposite to each other, and the electrode layer and the conductive layer between adjacent PPTC core materials 1 and PPTC core boards 63 are electrically connected. For example, the electrode layer and the conductive layer between adjacent PPTC core materials 1 and PPTC core boards 63 are arranged in a bonded manner and fixed by soldering with solder paste 8.

[0236] It should be noted that the multi-layer surface mount PPTC component can be made of the first basic composite unit 101 and the PPTC substrate 20 , or can be made of the first basic composite unit 101 , the second basic composite unit 102 and the PPTC substrate 20 .

[0237] The multi-layer surface mount PPTC element formed by the first basic composite unit 101 and the PPTC substrate 20 being arranged at intervals may be an even number of layers. Each first electrode layer 2 is electrically connected to each first conductive layer 61 , and correspondingly, each second electrode layer 3 is electrically connected to each second conductive layer 62 . The first welding pad 27 and the second welding pad 37 can be single-sided welded. For example, the first epitaxial electrode 21 located at the first outer surface 71 is bent to the second outer surface 72 to form the first welding pad 27, and the second epitaxial electrode 31 closest to the first outer surface 71 is bent to the second outer surface 72 to form the second welding pad 37. At this time, the second outer surface 72 has both the first welding pad 27 and the second welding pad 37. For another example, the first epitaxial electrode 21 located at the first outer surface 71 is bent to the second outer surface 72, and the first composite portion at the first outer surface 71 is partially exposed to form the first welding pad 27, and the second epitaxial electrode 31 closest to the second outer surface 72 is bent to the first outer surface 71 to form the second welding pad 37. At this time, the first outer surface 71 has both the first welding pad 27 and the second welding pad 37.

[0238] The multi-layer surface mount PPTC component formed by the first basic composite unit 101 and the PPTC substrate 20 being arranged at intervals can also be an odd number of layers. Each first electrode layer 2 is electrically connected to each first conductive layer 61, and correspondingly, each second electrode layer 3 is electrically connected to each second conductive layer 62. The number of first basic composite units 101 is one more than the number of PPTC substrates 20, and the first outer surface 71 and the second outer surface 72 correspond to the first basic composite unit 101. The first epitaxial electrode 21 located at the first outer surface 71 is bent to the second outer surface 72 to form a first welding pad 27, and the second epitaxial electrode 31 located at the second outer surface 72 is bent to the first outer surface 71 to form a second welding pad 37. A first reserved welding pad 28 is formed at the first outer surface 71 through the first composite part, and a second reserved welding pad 38 is formed at the second outer surface 72 through the second composite part. At this time, the multi-layer surface mount PPTC component is double-sided soldered.

[0239] In some embodiments, among the electrode layers corresponding to the first welding pad 27, at least one electrode layer forms a first conductive portion 24 extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the first conductive portion 24 of the electrode layer to form the first welding pad 27.

[0240] In some embodiments, in each electrode layer corresponding to the second welding pad 37: at least one electrode layer forms a second conductive portion 34 extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the second conductive portion 34 of the electrode layer to form the second welding pad 37.

[0241] In some embodiments, the multilayer surface mount PPTC component may further include a first reserved welding pad 28 formed by an electrode layer, which is used as a spare welding pad. The first reserved welding pad 28 is located on a side opposite to the first welding pad 27, and may be arranged directly opposite to the first welding pad 27. Of course, in other embodiments, the projection of the first reserved welding pad 28 in the thickness direction and the projection of the first welding pad 27 in the thickness direction are partially staggered or completely staggered, which is also within the protection scope of the present invention.

[0242] In some embodiments, the multilayer surface mount PPTC component may further include a second reserved welding pad 38 formed by the electrode layer, which is used as a spare welding pad. The second reserved welding pad 38 is located on a side opposite to the second welding pad 37, and may be arranged directly opposite to the second welding pad 37. Of course, in other embodiments, the projection of the second reserved welding pad 38 in the thickness direction and the projection of the second welding pad 37 in the thickness direction are partially staggered or completely staggered, which is also within the protection scope of the present invention.

[0243] In some embodiments, the surface of the outermost electrode layer or the surface of the conductive layer of the multi-layer surface-mounted PPTC element is partially covered with a third insulating portion 53 made of an insulating material, and the third insulating portion 53 can be arranged to cover the composite portion by coating. A second insulating portion 52 made of an insulating material can be arranged on the side of the PPTC core material 1 to electrically isolate the PPTC core material 1 from the conductive portion (such as the first conductive portion 24 or the second conductive portion 34). When the second insulating portion 52 is arranged between the side of the PPTC core material 1 at the end and the epitaxial electrode, the third insulating portion 53 and the second insulating portion 52 can be connected into one piece.

[0244] In the multi-layer surface mount PPTC component, each PPTC core material 1 may have the same thickness, or at least one of the PPTC core materials 1 may have a thickness different from that of other PPTC core materials 1. Each PPTC core material 1 may have the same known material, or at least one of the PPTC core materials 1 may have a known material different from that of other PPTC core materials 1.

[0245] In specific applications, multi-layer surface-mount PPTC components can produce many deformations. Figures 15 to 21 The implementation methods of double-layer, triple-layer, quad-layer and five-layer are further described by specific examples, wherein Figures 16 to 21 1 is a simplified diagram for simply illustrating the relationship between the basic composite unit 10 and the PPTC substrate 20 , wherein the insulating material is omitted.

[0246] Example 10

[0247] refer to Fig.14 This embodiment provides a double-layer surface-mount PPTC component, which is made of a first basic composite unit 101 and a PPTC substrate 20 .

[0248] The first basic composite unit 101 and the PPTC substrate 20 are stacked, the first electrode layer 2 and the first conductive layer 61 are electrically connected to form a first welding pad 27, and the second electrode layer 3 and the second conductive layer 62 are electrically connected to form a second welding pad 37. The composite part of the first electrode layer 2 is located at the first outer surface 71, the first epitaxial electrode 21 is bent twice continuously from the first outer surface 71 and covers the first conductive layer 61 at the second outer surface 72 to form the first welding pad 27, and the first welding pad 27 and the first conductive layer 61 are fixed by soldering with solder paste 8. The second electrode layer 3 and the second conductive layer 62 are arranged in affixed manner and fixed by soldering with solder paste 8, and the second epitaxial electrode 31 is bent continuously to the first conductive layer 61 to form the second welding pad 37.

[0249] like Fig.14 This embodiment has two second insulating parts 52. The second insulating part 52 on the left is used to electrically isolate the first epitaxial electrode 21 from the PPTC core material 1, the PPTC core plate 63, the second electrode layer 3 and the second conductive layer 62. The second insulating part 52 on the right is used to electrically isolate the second epitaxial electrode 31 from the PPTC core plate 63 and the second conductive part 34.

[0250] The first conductive layer 61 is covered with a third insulating portion 53 in an area avoiding the first welding pad 27. On the one hand, it directly isolates the second welding pad 37 and the first conductive layer 61, and on the other hand, it reduces the risk of short circuit when welding with an external circuit board. In this embodiment, the third insulating portion 53 at this location and the nearby second insulating portion 52 are connected into one piece.

[0251] The first composite part 25 is covered with a third insulating part 53 , and a fourth insulating part 54 is provided on the side of the double-layer surface-mount PPTC component. In this embodiment, the fourth insulating part 54 is connected to the third insulating part 53 on the first composite part 25 as a whole.

[0252] Embodiment 11

[0253] refer to Fig.15 The embodiment provides a double-layer surface-mount PPTC component, which is made of a first basic composite unit 101 and a PPTC substrate 20. The main difference between this embodiment and embodiment 10 is that the welding surface is different.

[0254] In this embodiment, the first basic composite unit 101 and a PPTC substrate 20 are stacked, the first electrode layer 2 and the first conductive layer 61 are electrically connected, and the second electrode layer 3 and the second conductive layer 62 are electrically connected to form a second welding pad 37. The first electrode layer 2 is located at the first outer surface 71, and the first epitaxial electrode 21 is bent twice continuously from the first outer surface 71 and covers the first conductive layer 61 at the second outer surface 72; the first composite part is partially exposed to form a first reserved welding pad 27. The second electrode layer 3 and the second conductive layer 62 are arranged in affixed manner and fixed by solder paste 8. The second epitaxial electrode 31 is continuously bent to the first electrode layer 2 to form a second welding pad 37, and the second epitaxial electrode 31 is connected to the PPTC core material 1 through the second insulating part 52 and is insulated and connected to the first electrode layer 2 through the third insulating part 53. By comparison, it can be seen that in embodiment 10, two welding pads are formed at the second outer surface 72 by two epitaxial electrodes, while in this embodiment, two welding pads are formed at the first outer surface 71 by one epitaxial electrode and the first composite part.

[0255] like Fig.15 This embodiment has two second insulating parts 52. The second insulating part 52 on the left is used to electrically isolate the first epitaxial electrode 21 from the PPTC core material 1, the PPTC core plate 63, the second electrode layer 3 and the second conductive layer 62. The second insulating part 52 on the right is used to electrically isolate the second epitaxial electrode 31 from the PPTC core material 1 and the first electrode layer 2.

[0256] In this embodiment, the third insulating portion 53 provided on the first electrode layer 2 is connected to the second insulating portion 52 on the right side. The third insulating portion 53 covered by the first conductive layer 61 in the area avoiding the first welding pad 27 and the second welding pad 37 is connected to the insulating material on the right side of the PPTC core board 63.

[0257] Example 12

[0258] refer to Fig.16 The embodiment provides a three-layer surface mount PPTC component, which is made of a first basic composite unit 101 , a second basic composite unit 102 and a PPTC substrate 20 .

[0259] The first basic composite unit 101, the PPTC substrate 20 and the second basic composite unit 102 are stacked in sequence. The first epitaxial electrode 21 located at the first outer surface 71 is continuously bent to the second outer surface 72 to form a first welding pad 27, and is insulated and connected to the second electrode layer 3 at the second outer surface 72. The second epitaxial electrode 31 closest to the first outer surface 71 (i.e., the second epitaxial electrode 31 of the first basic composite unit 101) is continuously bent to the second electrode layer 3 at the second outer surface 72 to form a second welding pad 37, and is fixed to the second electrode layer 3 at the second outer surface 72 by solder paste 8. Obviously, the first welding pad 27 and the second welding pad 37 are set on one side.

[0260] Fig.16 The figure simply illustrates the connection relationship between the two first epitaxial electrodes 21 . In practical applications, the two first epitaxial electrodes 21 may each form a first conductive portion 24 , and the two first conductive portions 24 are fitted together and fixedly connected by solder paste 8 .

[0261] In this embodiment, the first outer surface 71 may be coated with insulating material to form the third insulating portion 53 , and the second outer surface 72 may be coated with insulating material between the first welding pad 27 and the second welding pad 37 to form the third insulating portion 53 .

[0262] Example 13

[0263] refer to Fig.17 The embodiment provides a three-layer surface mount PPTC component, which is made of two first basic composite units 101 and a PPTC substrate 20 .

[0264] The PPTC substrate 20 is located between the two first basic composite units 101, each first electrode layer 2 and each first conductive layer 61 are electrically connected to form a first welding pad 27, and each second electrode layer 3 and each second conductive layer 62 are electrically connected to form a second welding pad 37. The first epitaxial electrode 21 located at the first outer surface 71 is continuously bent to the second outer surface 72 to form the first welding pad 27, the first composite part at the first outer surface 71 is partially exposed to form the first reserved welding pad 28, the second epitaxial electrode 31 located at the second outer surface 72 is continuously bent to the first outer surface 71 to form the second welding pad 37, and the second composite part at the second outer surface 72 is partially exposed to form the second reserved welding pad 38, thereby forming a double-sided welding structure.

[0265] Fig.17 The figure simply shows the connection relationship between the two first epitaxial electrodes 21. In actual application, the two first epitaxial electrodes 21 each form a first conductive part, and the two first conductive parts are arranged in close contact and fixedly connected by solder paste. Fig.17The figure simply illustrates the connection relationship between the two second epitaxial electrodes 31. In actual application, the two second epitaxial electrodes 31 each form a second conductive portion, and the two second conductive portions are arranged in close contact and fixedly connected by solder paste.

[0266] In this embodiment, the area of ​​the first outer surface 71 avoiding the second welding pad 37 can be coated with insulating material to form the third insulating portion 53 , and the area of ​​the second outer surface 72 avoiding the first welding pad 27 can be coated with insulating material to form the third insulating portion 53 .

[0267] Embodiment 14

[0268] refer to Fig.18 This embodiment provides a four-layer surface mount PPTC component, which is made of two first basic composite units 101 and two PPTC substrates 20 .

[0269] Each first electrode layer 2 is electrically connected to each first conductive layer 61, and each second electrode layer 3 is electrically connected to each second conductive layer 62. The first epitaxial electrode 21 located at the first outer surface 71 is continuously bent to the second outer surface 72 to form a first welding pad 27, and is electrically connected to the first conductive layer 61 at the second outer surface 72. The second epitaxial electrode 31 near the first outer surface 71 is continuously bent to the second outer surface 72 to form a second welding pad 37. The second welding pad 37 is insulated and connected to the first conductive layer 61 at the second outer surface 72, thereby forming a single-sided welding structure.

[0270] Fig.18 The figure simply shows the connection relationship between the two first epitaxial electrodes 21. In actual application, the two first epitaxial electrodes 21 each form a first conductive part, and the two first conductive parts are arranged in close contact and fixedly connected by solder paste. Fig.18 The figure simply illustrates the connection relationship between the two second epitaxial electrodes 31. In actual application, the two second epitaxial electrodes 31 each form a second conductive portion, and the two second conductive portions are arranged in close contact and fixedly connected by solder paste.

[0271] In this embodiment, the first outer surface 71 may be coated with insulating material to form the third insulating portion 53 , and the second outer surface 72 may be coated with insulating material in an area away from the first welding pad 27 to form the third insulating portion 53 . The third insulating portion 53 is bonded to the second welding pad 37 .

[0272] Embodiment 15

[0273] refer to Fig.19 This embodiment provides a four-layer surface mount PPTC component, which is made of two first basic composite units 101 and two PPTC substrates 20. The main difference between this embodiment and embodiment 14 is the position of the welding surface.

[0274] In this embodiment, each first electrode layer 2 is electrically connected to each first conductive layer 61, and each second electrode layer 3 is electrically connected to each second conductive layer 62. The first epitaxial electrode 21 located at the first outer surface 71 is continuously bent to the second outer surface 72, and is electrically connected to the first conductive layer 61 at the second outer surface 72. The first composite portion at the first outer surface 71 is partially exposed to form a first welding pad 27. The second epitaxial electrode 31 near the second outer surface 72 is continuously bent to the first outer surface 71 to form a second welding pad 37, and is insulated and connected to the first electrode layer 2 at the first outer surface 71. By comparison, it can be seen that in embodiment 15, two welding pads are formed at the second outer surface 72 by two epitaxial electrodes, while in this embodiment, two welding pads are formed at the first outer surface 71 by one epitaxial electrode and the first composite portion.

[0275] Fig.19 The figure simply shows that the two first epitaxial electrodes 21 are connected. In actual application, the two first epitaxial electrodes 21 each form a first conductive portion 24. The two first conductive portions 24 are arranged in close contact and fixedly connected by solder paste 8. Fig.19 The figure simply illustrates the connection relationship between the two second epitaxial electrodes 31 . In actual application, the two second epitaxial electrodes 31 each form a second conductive portion 34 . The two second conductive portions 34 are arranged in close contact and fixedly connected by solder paste 8 .

[0276] In this embodiment, the area of ​​the first outer surface 71 avoiding the first welding pad 27 can be coated with insulating material to form a third insulating portion 53 (not shown in the figure), and the second outer surface 72 can be partially or completely coated with insulating material to form the third insulating portion 53.

[0277] Example 16

[0278] refer to Fig. 20 This embodiment provides a five-layer surface mount PPTC component, which is made of three first basic composite units 101 and two PPTC substrates 20 .

[0279] In this embodiment, the first basic composite unit 101 and the two PPTC substrates 20 are alternately arranged. Each first electrode layer 2 is electrically connected to each first conductive layer 61, and each second electrode layer 3 is electrically connected to each second conductive layer 62. The first epitaxial electrode 21 located at the first outer surface 71 is continuously bent to the second outer surface 72 to form a first welding pad 27, and is insulated and connected to the second conductive layer 62 at the second outer surface 72. The first composite part at the first outer surface 71 is partially exposed to form a first reserved welding pad 28. The second epitaxial electrode 31 located at the second outer surface 72 is continuously bent to the first outer surface 71 to form a second welding pad 37, and is insulated and connected to the first conductive layer 61 located at the first outer surface 71. The second composite part at the second outer surface 71 is partially exposed to form a second reserved welding pad 38, thereby forming a double-sided welding structure.

[0280] Fig. 20 The figure simply shows the connection relationship between the three first epitaxial electrodes 21. In actual application, the three first epitaxial electrodes 21 each form a first conductive portion 24, wherein two first conductive portions 24 are respectively arranged in contact with the outermost first conductive portion 24 and fixedly connected by solder paste 8. Fig. 20 The figure simply illustrates the connection relationship between the three second epitaxial electrodes 31. In actual application, the three second epitaxial electrodes 31 each form a second conductive portion 34, wherein two second conductive portions 34 are respectively arranged to fit the outermost second conductive portion 34 and fixedly connected by solder paste 8.

[0281] In this embodiment, the area of ​​the first outer surface 71 avoiding the first reserved welding pad 28 can be coated with insulating material to form the third insulating portion 53, and the area of ​​the second outer surface 72 avoiding the second reserved welding pad 38 can be coated with insulating material to form the third insulating portion 53.

[0282] Embodiment 17

[0283] refer to Fig.21 This embodiment provides a five-layer surface mount PPTC component, which is made of two first basic composite units 101 , one second basic composite unit 102 and two PPTC substrates 20 .

[0284] In this embodiment, the basic composite unit and the PPTC substrate 20 are alternately arranged, each first electrode layer 2 is electrically connected to each first conductive layer 61, and each second electrode layer 3 is electrically connected to each second conductive layer 62. The first epitaxial electrode 21 located at the first outer surface 71 is continuously bent to the second outer surface 72 to form a first welding pad 27, and is insulated and connected to the second electrode layer 3 at the second outer surface 72. The second epitaxial electrode 31 near the first outer surface 71 is continuously bent to the second outer surface 72 to form a second welding pad 37, and is insulated and connected to the second electrode layer 3 located at the second outer surface 72, thereby forming a single-sided welding structure.

[0285] Fig.21 The figure simply shows the connection relationship between the three first epitaxial electrodes 21. In actual application, the three first epitaxial electrodes 21 each form a first conductive portion 24, wherein two first conductive portions 24 are respectively arranged in contact with the outermost first conductive portion 24 and fixedly connected by solder paste 8. Fig.21 The figure simply illustrates the connection relationship between the two second epitaxial electrodes 31 . In actual application, the two second epitaxial electrodes 31 each form a second conductive portion 34 . The two second conductive portions 34 are arranged in close contact and fixedly connected by solder paste 8 .

[0286] In this embodiment, the first outer surface 71 may be coated with insulating material to form the third insulating portion 53 , and the second outer surface 72 may be coated with insulating material in an area avoiding the second welding pad 37 to form the third insulating portion 53 , and the third insulating portion 53 is bonded to the first welding pad 27 .

[0287] Combined with the above technical information, it can be known that no matter which type of single-layer PPTC component, or a multi-layer surface-mount PPTC component made by multiple basic composite units 10, or a multi-layer surface-mount PPTC component made by using the basic composite unit 10 and the PPTC substrate 20, it has the following advantages: it does not need to use complex PCB processing technology for production, and eliminates the process from "etching insulating grooves on the upper metal foil 30 and the lower metal foil 20 respectively" to copper plating the first conductive through hole and the second conductive through hole. Instead, a process of bending the epitaxial electrode and coating or covering the insulating material at the position where insulation isolation is required is adopted. Obviously, the production process of the multi-layer surface-mount PPTC component of the present invention is simpler than the PCB processing process, and the production cost is lower. In addition, since there is no constraint on the precise positioning of the pattern in the multi-layer production, the production of multi-layer surface-mount PPTC components with more than three layers becomes possible.

[0288] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A single-layer surface-mount PPTC component, characterized in that: Made on the basis of a basic composite unit, the basic composite unit comprises a first electrode layer, a PPTC core material and a second electrode layer arranged in sequence, the first electrode layer extending relative to a first side surface of the PPTC core material to form a first epitaxial electrode; Among them, the first epitaxial electrode is bent along the PPTC core material and partially covers the second electrode layer, and an insulating material for electrical isolation is arranged between the first epitaxial electrode and the second electrode layer; the first electrode layer is partially exposed to form one or more first soldering pads, and the second electrode layer is partially exposed to form one or more second soldering pads. In the single-layer surface-mounted PPTC component, at least one outer surface has both the first soldering pad and the second soldering pad.

2. The single-layer surface mount PPTC component according to claim 1, characterized in that: The end of the second electrode layer corresponding to the first side does not extend out of the PPTC core material, the end of the second electrode layer corresponding to the second side of the PPTC core material does not extend out of the PPTC core material, and the second side and the first side are arranged oppositely; and / or, The area on the second electrode layer between the first pad and the second pad is covered with an insulating material; and / or, A side of the single-layer surface-mount PPTC component opposite to the first side is covered with an insulating material; and / or, The first electrode layer comprises a first composite part composited on the first surface of the PPTC core material, and a side of the first composite part facing away from the PPTC core material is covered with an insulating material; and / or, The side of the first electrode layer facing away from the first side surface is covered with an insulating material; and / or, The first electrode layer is isolated from the first side surface by an insulating material.

3. The single-layer surface mount PPTC component according to claim 1, characterized in that: A group of the first soldering pad and the second soldering pad are respectively provided on two outer surfaces of the single-layer surface-mounted PPTC component.

4. The single-layer surface mount PPTC component according to claim 1, characterized in that: One end of the second electrode layer opposite to the first side surface is bent along the PPTC core material and partially covers the first electrode layer, and an insulating material for electrical isolation is provided between the bent portion of the second electrode layer and the first electrode layer, and the portion of the second electrode layer covering the first electrode layer forms the second pad; The first composite part of the first electrode layer composited on the PPTC core material has another first solder pad; and / or the second composite part of the second electrode layer composited on the PPTC core material has another second solder pad.

5. The single-layer surface mount PPTC component according to claim 4, characterized in that: The two first pads are arranged opposite to each other; and / or, A first composite portion of the first electrode layer composited on the first surface of the PPTC core material, the side facing away from the PPTC core material, is partially covered with an insulating material; and / or, The two second pads are arranged opposite to each other; and / or, The second composite part of the second electrode layer composited with the second surface of the PPTC core material has a side facing away from the PPTC core material partially covered with an insulating material.

6. The single-layer surface mount PPTC component according to any one of claims 1 to 5, characterized in that: The first composite part of the first electrode layer is composited on the first surface of the PPTC core material; and / or the second composite part of the second electrode layer is composited on the second surface of the PPTC core material.

7. A multi-layer surface mounted PPTC component, characterized in that: Made on the basis of a plurality of basic composite units, the basic composite units include a PPTC core material and two electrode layers respectively arranged on two surfaces of the PPTC core material, and at least one of the electrode layers has an epitaxial electrode extending relative to the PPTC core material; Wherein: each of the basic composite units is stacked in the thickness direction, one electrode layer of each of the basic composite units is electrically connected to each other, and the electrode layer located at or near the outer surface is partially exposed to form a first welding pad; another electrode layer of each of the basic composite units is electrically connected to each other, and the electrode layer close to or located at the outer surface is partially exposed to form a second welding pad; each electrode layer corresponding to the first welding pad is electrically isolated from each electrode layer corresponding to the second welding pad; in the multi-layer surface-mounted PPTC component, at least one outer surface has both the first welding pad and the second welding pad.

8. The multi-layer surface mount PPTC component according to claim 7, characterized in that: Two adjacent basic composite units are insulated, isolated and fixed by insulating materials, and the two electrode layers between two adjacent PPTC core materials correspond to the first welding pad and the second welding pad respectively; or, The two adjacent PPTC core materials are electrically connected and are fitted and fixed.

9. The multi-layer surface mount PPTC component according to claim 7, characterized in that: In each electrode layer corresponding to the first welding pad: at least one electrode layer forms a first conductive portion extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the first conductive portion of the electrode layer to form one of the first welding pads; In each electrode layer corresponding to the second welding pad: at least one electrode layer forms a second conductive portion extending along the thickness direction by bending the epitaxial electrode, and one end of at least one electrode layer is bent relative to the second conductive portion of the electrode layer to form a second welding pad.

10. The multi-layer surface mount PPTC component according to claim 7, characterized in that: The two electrode layers of the basic composite unit are respectively a first electrode layer and a second electrode layer, and the PPTC core material has a first side surface and a second side surface which are arranged opposite to each other, wherein: In the first basic composite unit, the first electrode layer includes a first epitaxial electrode extending relative to the first side, and the second electrode layer includes a first epitaxial electrode extending relative to the second side; in the second basic composite unit, the first electrode layer includes a first epitaxial electrode extending relative to the first side, and the second electrode layer does not extend from the first side and the second side. In the multi-layer surface-mount PPTC component, each of the basic composite units adopts the first basic composite unit, or each of the basic composite units adopts the second basic composite unit, or a part of each of the basic composite units adopts the first basic composite unit and the other part adopts the second basic composite unit.

11. The multi-layer surface mount PPTC component according to claim 10, characterized in that: The multi-layer surface mount PPTC component is double-layer, wherein: Two basic composite units both adopt the first basic composite unit, the two first electrode layers are electrically connected, and a first welding pad is formed at each of the two outer surfaces of the multi-layer surface-mounted PPTC component, the two second electrode layers are electrically connected, and a second welding pad is formed at each of the two outer surfaces of the multi-layer surface-mounted PPTC component, and the first welding pad formed by the first epitaxial electrode and the second welding pad formed by the second epitaxial electrode are located at different outer surfaces of the multi-layer surface-mounted PPTC component; or, Two basic composite units both use the second basic composite unit, the electrode layers between the two PPTC core materials are electrically connected, one of the first epitaxial electrodes is bent to form the first welding pad, and the other first epitaxial electrode is bent to form the second welding pad; or, The two basic composite units respectively adopt the first basic composite unit and the second basic composite unit, and two first epitaxial electrodes form a first welding pad on each of the two outer surfaces of the multi-layer surface-mounted PPTC component.

12. The multi-layer surface mount PPTC component according to claim 10, characterized in that: The multi-layer surface mount PPTC component is made of a plurality of the first basic composite units, the two electrode layers between the adjacent PPTC core materials are insulated, and the two epitaxial electrodes located on the outer surface of the multi-layer surface mount PPTC component are respectively bent to opposite sides to form the first welding pad and the second welding pad respectively located on the two outer surfaces; or, The multi-layer surface mount PPTC component is made of one or more of the first basic composite units and one second basic composite unit, and the second basic composite unit is located at one end of the multi-layer surface mount PPTC component.

13. The multi-layer surface mount PPTC component according to any one of claims 7 to 12, characterized in that: The outermost electrode layer of the multi-layer surface-mounted PPTC component is partially covered with an insulating material; The thickness of each of the PPTC core materials is the same, or the thickness of at least one PPTC core material is different from that of other PPTC core materials; Each of the PPTC core materials is made of the same known material, or at least one PPTC core material is made of a known material different from that of other PPTC core materials.

14. A multi-layer surface mounted PPTC component, characterized in that: Made on the basis of basic composite unit and PPTC substrate; The basic composite unit comprises a first electrode layer, a PPTC core material and a second electrode layer arranged in sequence, wherein the first electrode layer extends out of the PPTC core material to form a first epitaxial electrode; The PPTC substrate comprises a first conductive layer, a PPTC core plate and a second conductive layer which are arranged in sequence, wherein the first conductive layer and the second conductive layer do not extend out of the periphery of the PPTC core plate; In the multi-layer surface-mounted PPTC component: the basic composite unit and the PPTC substrate are stacked, an electrode layer in each of the basic composite units and a conductive layer in each of the PPTC substrates are electrically connected to each other and partially exposed to form a first welding pad, another electrode layer in each of the basic composite units and another conductive layer in each of the PPTC substrates are electrically connected to each other and partially exposed to form a second welding pad; the multi-layer surface-mounted PPTC component has both the first welding pad and the second welding pad on at least one outer surface.

15. The multi-layer surface mount PPTC component according to claim 14, characterized in that: The multi-layer surface-mounted PPTC component has a first outer surface and a second outer surface that are arranged opposite to each other; the electrode layer and the conductive layer between adjacent PPTC core materials and PPTC core plates are electrically connected.

16. The multi-layer surface mount PPTC component according to claim 15, characterized in that: The basic composite unit adopts a first basic composite unit, the second electrode layer of the first basic composite unit includes a second epitaxial electrode extending relative to the PPTC core material, and the second epitaxial electrode and the first epitaxial electrode are located on opposite sides of the PPTC core material; The first basic composite units and the PPTC substrates are alternately arranged, each of the first electrode layers is electrically connected to each of the first conductive layers, and each of the second electrode layers is electrically connected to each of the second conductive layers, wherein: The first basic composite unit and the PPTC substrate have the same number, the first epitaxial electrode located on the first outer surface is bent to the second outer surface to form the first welding pad, and the second epitaxial electrode closest to the first outer surface is bent to the second outer surface to form the second welding pad; or, The first basic composite unit and the PPTC substrate have the same number, the first epitaxial electrode located on the first outer surface is bent to the second outer surface, the first electrode layer located on the first outer surface is partially exposed to form the first welding pad, and the second epitaxial electrode closest to the second outer surface is bent to the first outer surface to form the second welding pad; or, The number of the basic composite unit is one more than that of the PPTC substrate, the first epitaxial electrode located at the first outer surface is bent to the second outer surface to form a first welding pad, the first electrode layer located at the first outer surface is partially exposed to form another first welding pad, the second epitaxial electrode located at the second outer surface is bent to the first outer surface to form the second welding pad, and the second electrode layer located at the second outer surface is partially exposed to form another second welding pad.

17. The multi-layer surface mount PPTC component according to claim 15, characterized in that: The basic composite unit adopts a first basic composite unit and a second basic composite unit; the second electrode layer of the first basic composite unit includes a second epitaxial electrode extending relative to the PPTC core material, and the second epitaxial electrode and the first epitaxial electrode are located on opposite sides of the PPTC core material; in the second basic composite unit, the second electrode layer does not extend out of the periphery of the PPTC core material.

18. A method for preparing a single-layer surface mount PPTC component according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: A1. Prepare PPTC core material; A2, compounding electrode foils on the upper and lower surfaces of the PPTC core material to form a first electrode layer and a second electrode layer, and then irradiating and cross-linking by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, to obtain the basic composite unit; A3. Coating insulating material on the inner side of the epitaxial electrode and the surface of the electrode layer located on the surface layer, bending the first epitaxial electrode of the basic composite unit to form the first welding pad, and partially exposing the second electrode layer to form a second welding pad.

19. A method for preparing a multi-layer surface mount PPTC component according to any one of claims 7 to 13, characterized in that: The preparation method comprises the following steps: A1. Prepare PPTC core material; A2, compounding electrode foils on the upper and lower surfaces of the PPTC core material to form a first electrode layer and a second electrode layer, and then irradiating and cross-linking by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, to obtain the basic composite unit; A3. Coat insulating material on the inner side of the epitaxial electrode and the surface of the electrode layer located on the surface layer, stack a plurality of basic composite units, connect the epitaxial electrodes located on the same side of the stacked basic composite units, and form a first welding pad and a second welding pad on the outer surface of the stacked structure.

20. A method for preparing a multi-layer surface mount PPTC component according to any one of claims 14 to 17, characterized in that: The preparation method comprises the following steps: A1. Prepare PPTC core material; A2, compounding electrode foils on the upper and lower surfaces of the PPTC core material to form a first electrode layer and a second electrode layer, and then irradiating and cross-linking by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, to obtain the basic composite unit; A3. Coat insulating material on the inner side of the epitaxial electrode and on the surface of the electrode layer located on the surface layer, apply solder paste to the basic composite unit and the PPTC substrate and stack them, connect the epitaxial electrodes of each basic composite unit located on the same side after stacking, and form a first welding pad and a second welding pad on the outer surface of the stacked structure.

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