Multilayer PPTC element and preparation method thereof

Abstract

The invention discloses a multilayer PPTC element and a preparation method thereof, and belongs to the technical field of thermistors. The multilayer PPTC element includes a body structure and an electrode structure. The main body structure is manufactured on the basis of a plurality of composite units, a plurality of PPTC core materials are arranged in parallel, and the main body structure is provided with two electrode connecting surfaces or surface groups. And the electrode structure comprises two electrode components which are respectively arranged on the first electrode connecting surface or surface group and the second electrode connecting surface or surface group, and is used as electrodes for connecting the multi-layer PPTC element and an external component. Different types of PPTC elements, such as a plug-in type PPTC element, a terminal type PPTC element and a strip-shaped PPTC element, can be formed due to different types of electrode structures and different relationships between the electrode structures and the main body structure. The multilayer PPTC element provided by the invention can realize the breakthrough of producing multilayer plug-in type, multilayer terminal type and multilayer strip-shaped PPTC elements, and is simple in production steps and high in production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of thermistors, and in particular to a multilayer PPTC element 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] refer to Figure 1 In the production process of PPTC components, the raw materials are weighed according to the ratio, refined, granulated and formed to obtain the PPTC core material 100, and the PPTC core material 100, the first conductive layer 200 and the second conductive layer 300 are compounded to obtain a composite board, which is equivalent to a collection of several PPTC substrates. Depending on the type of PPTC components to be produced, the subsequent processing technology is different. For plug-in type, terminal type and strip PPTC components, select appropriate electrode sheets or leads, weld electrode sheets on the first conductive layer 200 and the second conductive layer 300 respectively, and then the plug-in type and strip PPTC components can be encapsulated.

[0005] However, in the prior art, plug-in type, terminal type and strip-shaped PPTC components on the market only have a single-layer structure, and it is impossible to produce multi-layer structure products. Summary of the invention

[0006] One of the purposes of the present application is to provide a multi-layer PPTC component and a preparation method thereof, which can be used to produce plug-in type, strip type and terminal type products, thereby solving the problem that the prior art cannot produce multi-layer plug-in type, multi-layer terminal type and multi-layer strip PPTC products.

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

[0008] A multilayer PPTC component is made on the basis of a plurality of composite units; the composite unit comprises a PPTC core material and electrode layers arranged on two surfaces of the PPTC core material, and when the electrode layer extends out of the PPTC core material, the extended portion is an epitaxial electrode;

[0009] The multilayer PPTC element has two electrode connection surfaces or surface groups, which are a first electrode connection surface or surface group located on the first surface or surface group and a second electrode connection surface or surface group located on the second surface;

[0010] After each of the composite units is stacked, the first side and the second side of the multilayer PPTC element each have at least one epitaxial electrode, wherein the first side and the second side are arranged opposite to each other;

[0011] The epitaxial electrode is bent so that: one electrode layer in each of the composite units is electrically connected to each other and forms the first electrode connection surface or surface group, or can be electrically connected through a conductor at the first electrode connection surface or surface group, and another electrode layer in each of the composite units is electrically connected to each other and forms the second electrode connection surface or surface group, or can be electrically connected through a conductor at the second electrode connection surface or surface group;

[0012] When the epitaxial electrode is bent, the electrode layer corresponding to the first electrode connection surface or surface group is electrically isolated from the electrode layer corresponding to the second electrode connection surface or surface group.

[0013] Optionally, two electrode layers between adjacent PPTC core materials are fixed by welding and electrically connected, or bonded by insulating materials and electrically isolated.

[0014] Optionally, at least part of the side surfaces of the PPTC core material are provided with insulating material to electrically isolate the bent epitaxial electrode.

[0015] Optionally, at least one of the electrode connection surfaces or surface groups is arranged continuously, and the continuously arranged electrode connection surfaces or surface groups are realized by any of the following methods:

[0016] (1) The epitaxial electrode partially covers the electrode layer located at the outermost layer of the multi-layer PPTC component and is electrically connected thereto, and the portion of the electrode layer located at the outermost layer of the multi-layer PPTC component that is not covered by the epitaxial electrode forms an electrode connection surface or surface group;

[0017] (2) The epitaxial electrode covers the electrode layer located at the outermost layer of the multi-layer PPTC element and is insulated and connected thereto. The coverage area of ​​the epitaxial electrode extends from the first side to the second side, and the surface of the coverage area forms an electrode connection surface or surface group.

[0018] Optionally, at least one of the electrode connection surfaces or surface groups includes a first region and a second region that are intermittently arranged, wherein the electrode connection surface or surface group is realized by any of the following methods:

[0019] (1) The first region is formed by an electrode layer located at the outermost layer of the multi-layer PPTC element and composited on the PPTC core material, and the second region is formed by bending the epitaxial electrode to be flush with the electrode layer;

[0020] (2) The first region is formed by an electrode layer located at the outermost layer of the multi-layer PPTC element and composited on the PPTC core material, the portion of the epitaxial electrode covering the electrode layer is a covering portion, and the second region is a surface of the covering portion.

[0021] Optionally, the multilayer PPTC element is made of a plurality of second composite units, or is made of the first composite unit and the third composite unit, or is made of the second composite unit and the third composite unit, or is made of the first composite unit, the second composite unit and the third composite unit;

[0022] Among them, in the first composite unit, each of the two electrode layers has one epitaxial electrode, and the two epitaxial electrodes are located on opposite sides of the PPTC core material; the second composite unit has only one epitaxial electrode; in the third composite unit, the peripheries of the two electrode layers do not extend out of the PPTC core material.

[0023] Optionally, there are two composite units, both of which use the second composite unit, wherein:

[0024] The electrode layer having the epitaxial electrode is bonded between two PPTC core materials through an insulating material, wherein one epitaxial electrode and the electrode layer at the first surface or surface group correspond to the first electrode connection surface or surface group, and the other epitaxial electrode and the electrode layer at the second surface correspond to the second electrode connection surface or surface group; or

[0025] After stacking, the two electrode layers with epitaxial electrodes are respectively located between the second surface and the two PPTC core materials, wherein the epitaxial electrode located on the second surface and the electrode layer located on the first surface or surface group correspond to the first electrode connection surface or surface group, and the epitaxial electrode located between the two PPTC core materials is bent to the second surface and extends from the first side to the second side.

[0026] Optionally, there are three composite units, one of which is the first composite unit and the other two are the third composite units, wherein:

[0027] The first composite unit is arranged between two third composite units, the electrode layers between adjacent PPTC core materials are welded and fixed, one epitaxial electrode is bent to partially cover the electrode layer located on the first surface or surface group and is electrically connected thereto, and the other epitaxial electrode is bent to partially cover the electrode layer located on the second surface and is electrically connected thereto.

[0028] Optionally, from the first surface or surface group to the second surface, the composite units respectively use the second composite unit, the second composite unit, the first composite unit, the second composite unit and the second composite unit; the electrode layers between adjacent PPTC core materials are welded and fixed;

[0029] Among the three epitaxial electrodes located on the same side, the electrode layers corresponding to two of the epitaxial electrodes are located between the two PPTC core materials, and the two epitaxial electrodes are bent in opposite directions, and the other epitaxial electrode is bent from a position close to one end of the multi-layer PPTC component and partially covers the electrode layer located at the other end of the multi-layer PPTC component.

[0030] Optionally, the multilayer PPTC element further includes a first electrode member and a second electrode member;

[0031] The first electrode member is fixed on the first electrode connection surface or surface group and forms an electrical connection relationship with the electrode layer corresponding to the first electrode connection surface or surface group;

[0032] The second electrode component is fixed on the second electrode connection surface or surface group, and forms an electrical connection relationship with the electrode layer corresponding to the second electrode connection surface or surface group.

[0033] Optionally, the first electrode member and the second electrode member are respectively in sheet shape, and the periphery of the first electrode member and the periphery of the second electrode member do not extend out of the side surface of the multi-layer PPTC element.

[0034] Optionally, one side of the first electrode component extends out relative to each of the PPTC core materials to form a first extension portion, and one side of the second electrode component extends out relative to each of the PPTC core materials to form a second extension portion.

[0035] Optionally, the first electrode member and the second electrode member use leads, and the first extension portion and the second extension portion are located on the same side.

[0036] Optionally, the first electrode member and the second electrode member are electrode sheets, and the first protruding portion and the second protruding portion are located on opposite sides.

[0037] Optionally, a surface of the multi-layer PPTC element is wrapped with an encapsulation structure, and the first protruding portion and the second protruding portion extend out of the encapsulation structure.

[0038] Optionally, each of the PPTC core materials has the same thickness, or the thickness of at least one PPTC core material is different from the thickness of other PPTC core materials;

[0039] 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.

[0040] A method for preparing a multilayer PPTC component as described in any one of the above items, comprising the following steps

[0041] A1. Prepare PPTC core material;

[0042] A2. Electrode foils are respectively composited on the upper and lower surfaces of the PPTC core material to form electrode layers, and then irradiated and cross-linked by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, thereby preparing the desired composite unit;

[0043] A3. An insulating material is disposed on the inner side of the epitaxial electrode. After the composite units are stacked, the epitaxial electrodes on the same side are bent to form the first electrode connection surface or surface group and the second electrode connection surface or surface group.

[0044] The present invention has at least the following beneficial effects:

[0045] 1. The multi-layer PPTC component is made of composite units. After each composite unit is stacked, the first side and the second side have epitaxial electrodes. The epitaxial electrodes are processed to connect each PPTC core material in parallel and form a first electrode connection surface or surface group and a second electrode connection surface or surface group. The two electrode connection surfaces or surface groups can cooperate with the lead electrodes and sheet electrodes to form a multi-layer plug-in PPTC component, a multi-layer terminal PPTC component and a multi-layer strip PPTC component, which achieves a breakthrough in the production of multi-layer plug-in PPTC components, multi-layer terminal PPTC components and multi-layer strip PPTC components from a structural perspective.

[0046] 2. In the prior art, the production process and production equipment of plug-in PPTC components, terminal PPTC components and strip PPTC components are all based on PPTC substrates. Due to the maturity of the production process and production line, the PPTC substrate is always in the form of flush sides. Improving the PPTC substrate involves process adjustment and the resulting production line adjustment. People are accustomed to producing according to the existing technology. Subject to the existing production process, production line and people's inertial thinking, no one has ever proposed to produce a multilayer structure by deforming the PPTC substrate; but the present invention is based on composite units. In several composite units, there are at least two epitaxial electrodes. By bending the epitaxial electrodes and setting the relationship between the electrode layers, the parallel connection between the PPTC core materials 1 is realized. Among them, the process of composite units with epitaxial electrodes is different from the existing process, and the various processes involved in stacking the composite units and the process of connecting the composite units are also different from the prior art. In other words, the present invention breaks through the limitations of traditional production processes and breaks inertial thinking.

[0047] 3. The present invention is a huge breakthrough in business. The multi-layer plug-in PPTC components, multi-layer terminal PPTC components and multi-layer strip PPTC components generated by the composite unit 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, which shows that the commercial value is huge. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] 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.

[0049] Figure 1 It is a structural schematic diagram of an existing PPTC substrate.

[0050] Figure 2 This is a schematic structural diagram of the first composite unit of Example 1 of the present invention.

[0051] Figure 3 This is a schematic structural diagram of the second composite unit of Example 2 of the present invention.

[0052] Figure 4 This is a schematic structural diagram of the third composite unit of Example 3 of the present invention.

[0053] Figure 5 Schematic diagram of the structure of a double-layer PPTC component according to Embodiment 4 of the present invention.

[0054] Figure 6 FIG. 4 is a schematic structural diagram of a double-layer PPTC component according to an embodiment of the present invention.

[0055] Figure 7 Schematic diagram of the structure of a double-layer PPTC component according to Embodiment 5 of the present invention.

[0056] Figure 8 FIG. 4 is a schematic structural diagram of a double-layer PPTC component according to an embodiment of the present invention.

[0057] Fig. 9 Schematic diagram of the structure of a double-layer PPTC component according to Example 6 of the present invention.

[0058] Fig.10 Schematic diagram of the structure of a double-layer PPTC component according to Embodiment 7 of the present invention.

[0059] Fig.11 Schematic diagram of the structure of a double-layer PPTC component according to Example 8 of the present invention.

[0060] Fig.12 FIG. 4 is a schematic structural diagram of a double-layer PPTC component according to an embodiment of the present invention.

[0061] Fig.13 FIG. 4 is a schematic structural diagram of a double-layer PPTC component according to an embodiment of the present invention.

[0062] Fig.14 FIG. 4 is a schematic structural diagram of a double-layer PPTC component according to an embodiment of the present invention.

[0063] Fig.15 Schematic diagram of the structure of a three-layer PPTC component according to Embodiment 9 of the present invention.

[0064] Fig.16 Schematic diagram of the structure of a three-layer PPTC component according to Embodiment 9 of the present invention.

[0065] Fig.17 FIG. 4 is a schematic diagram of the structure of a three-layer PPTC component according to an embodiment of the present invention.

[0066] Fig.18 FIG. 4 is a schematic diagram of the structure of a three-layer PPTC component according to an embodiment of the present invention.

[0067] Fig.19 Schematic diagram of the structure of a three-layer PPTC component according to Embodiment 10 of the present invention.

[0068] Fig. 20 Schematic diagram of the structure of a five-layer PPTC component according to Example 11 of the present invention.

[0069] Fig.21 Schematic diagram of the structure of a five-layer PPTC component according to Example 11 of the present invention.

[0070] Fig. 22 FIG. 4 is a schematic diagram of the structure of a five-layer PPTC component according to an embodiment of the present invention.

[0071] Fig.23FIG. 4 is a schematic diagram of the structure of a five-layer PPTC component according to an embodiment of the present invention.

[0072] Fig.24 This is a schematic diagram of the structure of a five-layer PPTC component according to Example 12 of the present invention.

[0073] Fig.25 FIG. 4 is a schematic structural diagram of a double-layer PPTC component according to an embodiment of the present invention.

[0074] Reference numerals:

[0075] The present invention:

[0076] 10, first composite unit; 20, second composite unit; 30, third composite unit;

[0077] 1. PPTC core material; 11. First surface; 12. Second surface; 13. First side surface; 14. Second side surface

[0078] 2. first electrode layer; 21. first composite portion; 22. first epitaxial electrode;

[0079] 3. second electrode layer; 31. second composite portion; 33. second epitaxial electrode;

[0080] 41. first electrode connection surface or surface group; 42. second electrode connection surface or surface group; 43. first region; 44. second region;

[0081] 51. first face or face group; 52. second face; 53. first side; 54. second side;

[0082] 61. first insulating portion; 62. second insulating portion; 63. third insulating portion;

[0083] 71. first electrode member; 72. second electrode member; 73. first extension portion; 74. second extension portion;

[0084] 8. Encapsulation structure;

[0085] 9. Solder paste;

[0086] Existing technology:

[0087] 100, PPTC core material; 200, first conductive layer; 300, second conductive layer. DETAILED DESCRIPTION

[0088] 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.

[0089] 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.

[0090] The welding technology involved in the following description adopts the method of first applying solder paste for initial positioning. After all the solder pastes are positioned, the solder paste is melted to achieve welding and fixation. The solder paste is used to represent 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.

[0091] The multilayer PPTC element provided in the embodiment of the present invention is made on the basis of the composite unit. The following first describes the overall structure of the composite unit and the multilayer PPTC element, and then describes the preparation method of the PPTC core material, the preparation method of the composite unit and the preparation method of the multilayer PPTC element. Figures 2 to 24 Composite units and multi-layer PPTC components are illustrated by several embodiments.

[0092] refer to Figures 2 to 4 Understand. The embodiment of the present invention provides a composite unit, including a PPTC core material 1 and electrode layers arranged on two surfaces of the PPTC core material 1, when the electrode layer extends out of the PPTC core material 1, the extended portion is an epitaxial electrode. The PPTC core material 1 can be a thin sheet, and its two surfaces are a first surface 11 and a second surface 12, and the electrode layer includes a first electrode layer 2 connected to the first surface 11 and a second electrode layer 3 connected to the second surface 12.

[0093] Each electrode layer has a composite part for connecting to the PPTC core material 1. For example, the first electrode layer 2 has a first composite part 21, and the second electrode layer 3 has a second composite part 31. The first composite part 21 and the second composite part 31 are respectively bonded and connected to the PPTC core material 1. In some embodiments, the PPTC core material 1, the first composite part 21 and the second composite part 31 are composite-molded. The composite molding process can adopt existing technology, such as hot pressing molding by a hot press.

[0094] In some embodiments, the thickness of the electrode layer is within 8.0 μm to 100 μm, such as 8.0 μm, 45 μm or 100 μm. The volume resistivity of the electrode layer is lower than 10 μΩ.cm. The side of the electrode layer that is bonded to the PPTC core material 1 is a roughened surface to improve the bonding strength between the two. The electrode layer has a nickel plating layer on its roughened surface or both sides. The electrode layer can be made of electrode foil, the substrate of the electrode foil is made of metal or metal alloy, and preferably the electrode layer is made of one of electrolytic copper foil and rolled copper foil.

[0095] When the relationship between the electrode layer and the PPTC core material 1 is different, the type of the composite unit is different. The first composite unit 10 and the second composite unit 20 both have epitaxial electrodes, and the third composite unit 30 does not have an epitaxial electrode. Figure 2 As shown, in the first composite unit 10, each of the two electrode layers has an epitaxial electrode, and the two epitaxial electrodes are located on opposite sides of the PPTC core material 1, that is, the first electrode layer 2 has a first epitaxial electrode 22 extending relative to the first side 13 of the PPTC core material 1, and the second electrode layer 3 has a second epitaxial electrode 32 extending relative to the second side 14 of the PPTC core material 1, and the first side 13 and the second side 14 are arranged opposite to each other. Figure 3 As shown, only one epitaxial electrode is provided in the second composite unit 20, and the other peripheries of the two electrode layers do not extend out of the PPTC core material 1. Figure 4 The third composite unit 30 is not provided with an epitaxial electrode, that is, the periphery of the two electrode layers does not extend out of the PPTC core material 1. Of course, the third composite unit 30 can also be interpreted as Figure 1 The prior art (ie, PPTC substrate) is shown.

[0096] 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, during compounding, the first electrode layer 2 and / or the second electrode layer 3 are extended out of the PPTC core material 1 by a certain length according to design requirements; of course, when preparing the third composite unit 30, it is not necessary to extend the electrode layer out of the PPTC core material 1.

[0097] 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 PPTC core materials 1. In the width direction of the product, a portion for forming an epitaxial electrode is reserved or no epitaxial electrode is reserved as needed to obtain a composite unit.

[0098] In the application of the composite unit, the epitaxial electrode can be processed (such as bending, folding, welding, cutting or other operations) and used as an electrode for connecting components outside the composite unit. The composite unit can be used to make various types of PPTC components. The present invention focuses on its application in multi-layer PPTC components, especially in multi-layer plug-in PPTC components, multi-layer terminal PPTC components and multi-layer strip PPTC components.

[0099] The multilayer PPTC component includes a main structure and an electrode structure. Several PPTC core materials 1 of the main structure are arranged in parallel, and the main structure has two electrode connection surfaces or surface groups, namely, a first electrode connection surface or surface group 41 located on one side of the main structure, and a second electrode connection surface or surface group 42 located on the other side of the main structure (the first electrode connection surface or surface group 41 is located on the first surface or surface group 51 of the multilayer PPTC component, and the second electrode connection surface or surface group 42 is located on the second surface 52 of the multilayer PPTC component). The electrode structure includes two electrode components respectively mounted on the first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42, so that the PPTC core material 1 after parallel connection has a pair of electrodes for connecting to external components (such as a circuit board). Different types of electrode structures and different relationships between the electrode structure and the main structure can form different types of PPTC components (such as plug-in PPTC components, terminal PPTC components, and strip PPTC components).

[0100] It should be noted that the electrode connection surface or surface group is defined as a single surface or a surface group consisting of multiple surfaces on the main structure that is connected to the electrode structure. Figure 6 and Fig.25 understand, Figure 6 In the embodiment, the first electrode member 71 is attached to the second electrode layer 3 above, and the area where the two are attached is the electrode connection surface or surface group. In this case, the electrode connection surface adopts a single continuously arranged surface; Fig.25 In the embodiment, the first electrode member 71 is simultaneously attached to and connected with the second electrode layer 3 above and the surface of the covering portion bent onto the second electrode layer 3. At this time, a part of the electrode connection surface is located on the second electrode layer 3, and another part is located on the covering portion. In addition, as Figure 6 and Fig.25 As shown, the two multilayer PPTC components have the same main structure, but different electrode connection surfaces, and two solutions with different connection positions of the main structure and the electrode structure.

[0101] In terms of construction, the main structure can have different interpretations. The first interpretation is that the main structure includes a number of PPTC core materials 1 and electrode layers that are spaced apart, a portion of the electrode layers can establish an electrical connection relationship and can form a first electrode connection surface or surface group 41, and another portion of the electrode layers can establish an electrical connection relationship and can form a second electrode connection surface or surface group 42; the electrode layers are divided into two categories, one type of electrode layer has an edge that does not extend beyond the edge of the PPTC core material 1, and the other type of electrode layer has an epitaxial electrode that extends relative to the PPTC core material 1, and the electrical connection between the electrode layers is directly or indirectly achieved by bending the epitaxial electrode. The second interpretation describes the main structure on the basis of the composite unit. Considering that the inventive concept and original intention of improvement of this technology are based on the composite unit, the present invention mainly adopts the second interpretation to describe the multilayer PPTC component and its preparation method.

[0102] Specifically, the main structure is made on the basis of a plurality of composite units. After the composite units are stacked, the first side 53 and the second side 54 of the multilayer PPTC element respectively have at least one epitaxial electrode, and the first side 53 and the second side 54 are arranged opposite to each other. Of course, the epitaxial electrodes on the first side 53 and the epitaxial electrodes on the second side 54 correspond to different electrode connection surfaces or surface groups. The epitaxial electrodes are bent so that: one electrode layer in each composite unit is electrically connected to each other and forms the first electrode connection surface or surface group 41, or can be electrically connected at the first electrode connection surface or surface group 41 through a conductor, and another electrode layer in each composite unit is electrically connected to each other and forms the second electrode connection surface or surface group 42, or can be electrically connected at the second electrode connection surface or surface group 42 through a conductor. An insulating material is provided on the epitaxial electrode to electrically isolate the electrode layer corresponding to the first electrode connection surface or surface group 41 from the electrode layer corresponding to the second electrode connection surface or surface group 42.

[0103] In the main structure, there are many ways to connect two adjacent composite units, such as bonding and welding through insulating materials. The main difference between these two fixing methods is whether the two electrode layers located between the two adjacent PPTC core materials 1 are insulated or conductively connected. For ease of description, the two electrode layers are defined as the first connection layer and the second connection layer, respectively.

[0104] In the adhesive fixing method, a first insulating portion 61 (such as a first insulating portion 61 made of insulating material) is provided between the first connecting layer and the second connecting layer. Figures 5 to 10 ) for insulation isolation, the first insulating portion 61 is bonded and fixed to the first connection layer and the second connection layer respectively, and the electrode connection surface or surface group corresponding to the first connection layer is different from the electrode connection surface or surface group corresponding to the second connection layer.

[0105] 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 98 between the two, and then fix them by reflow soldering), and the first connection layer and the second connection layer correspond to the same electrode connection surface or surface group.

[0106] In a specific embodiment, all adjacent composite units may be connected by bonding or welding, or some adjacent composite units may be bonded and fixed, while other adjacent composite units may be welded and fixed, as long as the parallel connection of the PPTC core materials 1 can be achieved.

[0107] In the main structure, at least part of the side of the PPTC core material 1 is provided with a second insulating portion 62 made of insulating material (for example Figures 5 to 24), the second insulating part 62 electrically isolates the PPTC core material 1 where it is located from the adjacent epitaxial electrode. When the electrode layers between adjacent PPTC core materials 1 are connected through the first insulating part 61, the first insulating part 61 can be connected to the second insulating parts 62 at both ends thereof.

[0108] The main structure may also have a third insulating portion 63. When the epitaxial electrode is continuously bent to cover the outermost electrode layer and corresponds to a different electrode connection surface or surface group of the electrode layer, the two are electrically isolated by the third insulating portion 63. Fig.11 shown.

[0109] In the main structure, 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 be made of the same known material, or at least one of the PPTC core materials 1 may be made of a known material different from that of other PPTC core materials 1. When the formula and / or thickness of the PPTC core materials 1 in two multi-layer PPTC components are different, the holding current and / or rated voltage of the two-layer PPTC components are different, and in practical applications, products with different safety levels can be obtained.

[0110] In the main structure, the electrode connection surface or surface group is formed by one or more electrode layers. The electrode connection surface or surface group can be presented in the form of a single continuous surface or a combination of non-continuous surfaces composed of multiple surfaces. These two methods are explained separately below.

[0111] When the electrode connection surfaces or surface groups are arranged continuously, the continuously arranged electrode connection surfaces or surface groups can be formed by any of the following methods:

[0112] (1) The epitaxial electrode partially covers the electrode layer located at the outermost layer of the multilayer PPTC component and is electrically connected thereto, and the portion of the electrode layer located at the outermost layer of the multilayer PPTC component that is not covered by the epitaxial electrode forms an electrode connection surface or surface group, such as Figure 5 The first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42, Figure 7 and Fig.10 The first electrode connection surface or surface group 41 in.

[0113] (2) The epitaxial electrode covers the electrode layer located at the outermost layer of the multi-layer PPTC component and is insulated from it. The coverage area of ​​the epitaxial electrode extends from the first side 53 to the second side 54. The width of the coverage area is preferably the same as the width of the electrode layer at the outermost layer of the multi-layer PPTC component. The surface of the coverage area forms the first electrode connection surface or surface group 41, such as Fig.11 The second electrode connection surface or surface group 42.

[0114] When the electrode connection surface or surface group adopts a non-continuous surface composed of multiple surfaces, it is formed by multiple electrode layers, and the electrode connection surface or surface group includes a first area 43 and a second area 44 that are intermittently arranged, wherein the electrode connection surface or surface group is realized by any of the following methods:

[0115] (1) The first region 43 is formed by the electrode layer (i.e., the outermost composite part) located on the outermost layer of the multi-layer PPTC element and composited on the PPTC core material, and the second region 44 is formed by bending the epitaxial electrode to be flush with the electrode layer. The second region 44 can be the end surface of a single epitaxial electrode, such as Figure 7 As shown, the end faces of multiple epitaxial electrodes may be formed together, such as Fig.21 shown.

[0116] (2) The first region 43 is formed by the electrode layer located at the outermost layer of the multi-layer PPTC component and composited on the PPTC core material 1. The part of the epitaxial electrode covering the electrode layer is the covering part, and the second region 44 is the surface of the covering part. The first region 43 and the second region 44 are two staggered single surfaces. It should be noted that, first, most of the current PPTC face groups are very small components, and each electrode layer and the PPTC core material 1 are thin sheets. Although the first region 43 and the second region 44 are staggered, they do not affect the conductive function at all when connected to the electrode structure (i.e., the first electrode component 71 and the second electrode component 72), and do not affect the appearance. In addition, this method has advantages in terms of reliability and stability of electrical connection, and the production process is not more complicated than other methods. Of course, at present and in the future, it is not ruled out that some application conditions have the need for large-size PPTC components, so that the thickness of the covering part affects the product performance, installation process or appearance effect, then the electrode connection surface or face group may adopt a form other than this method. Second, when the main structures of two multi-layer PPTC components are the same, the electrode connection surfaces may be different, such as Figure 6 and Fig.25 As shown, accordingly, the two multi-layer PPTC components are different embodiments.

[0117] In a specific embodiment, the first electrode connection surface or surface group 41 can be implemented by any of the above methods. Similarly, the second electrode connection surface or surface group 42 can be implemented by any of the above methods. In other words, the two electrode connection surfaces or surface groups of the multilayer PPPTC element can both adopt a single continuous surface, such as Figure 5 , Fig.11 As shown, non-continuous surfaces composed of multiple surfaces can also be used, such as Fig.10 As shown, or a single continuous face and a non-continuous face composed of multiple faces are used respectively, such as Fig. 9 shown.

[0118] As described above, the composite unit has three types, namely, the first composite unit 10, the second composite unit 20 and the third composite unit 30. Accordingly, the main structure also has different types. The main structure can be made of a plurality of second composite units 20 (for example, Figures 5 to 14 ), or made by the first composite unit 10 and the third composite unit 30 (for example Figures 15 to 18 ), or is made by the second composite unit 20 and the third composite unit 30 (for example Fig.19 ), or is made by the first composite unit 10, the second composite unit 20 and the third composite unit 30 (for example Figure 20 to Figure 24 ).

[0119] The electrode structure includes a first electrode component 71 and a second electrode component 72; the first electrode component 71 is soldered on the first electrode connecting surface or surface group 41 by solder paste, and forms an electrical connection relationship with the electrode layer corresponding to the first electrode connecting surface or surface group 41, wherein when the first electrode connecting surface or surface group 41 is a single continuous surface, the first electrode component 71 simultaneously connects the first area 43 and the second area 44 of the first electrode connecting surface or surface group 41, so that an electrical connection relationship is formed between the corresponding electrode layers; the second electrode component 72 is soldered on the second electrode connecting surface or surface group 42 by solder paste, and forms an electrical connection relationship with the electrode layer corresponding to the second electrode connecting surface or surface group 42, and the second electrode component 72 simultaneously connects the first area 43 and the second area 44 of the second electrode connecting surface or surface group 42, so that an electrical connection relationship is formed between the corresponding electrode layers.

[0120] In some embodiments, the first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42 are both non-continuous surfaces composed of multiple surfaces, the first electrode component 71 and the second electrode component 72 are respectively in the form of sheets, and the periphery of the first electrode component 71 and the periphery of the second electrode component 72 are aligned with the side of the multi-layer PPTC element, thereby forming a multi-layer terminal type PPTC element.

[0121] In some embodiments, one side of the first electrode component 71 extends relative to each PPTC core material 1 to form a first extension portion 73, and one side of the second electrode component 72 extends relative to each PPTC core material 1 to form a second extension portion 74. Different forms of electrode components and different positional relationships between the first extension portion 73 and the second extension portion 74 and the PPTC core material 1 can form different products. Among them, when the first electrode member 71 and the second electrode member 72 use leads, and the first extension portion 73 and the second extension portion 74 are located on the same side, a multi-layer plug-in PPTC element is formed, and accordingly, one of the first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42 uses a continuous surface, and the other uses a discontinuous surface, or both electrode connection surfaces or surface groups use discontinuous surfaces; when the first electrode member 71 and the second electrode member 72 use electrode sheets, and the first extension portion 73 and the second extension portion 74 are located on opposite sides, a multi-layer strip PPTC element is formed, and accordingly, the first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42 can use two continuous surfaces, or two discontinuous surfaces, or one and a continuous surface, and the other is a discontinuous surface.

[0122] The surfaces of the multi-layer plug-in PPTC components and the multi-layer strip PPTC components may be wrapped with an encapsulation structure 8, and the first extension portion 73 and the second extension portion 74 extend out of the encapsulation structure 8. The encapsulation structure 8 may be formed by coating an insulating coating, such as epoxy resin.

[0123] The above is an overall description of the composite unit and the multi-layer PPTC component. Next, the PPTC core material 1, the preparation method of the composite unit and the preparation method of the multi-layer PPTC component are described.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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:

[0130] 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;

[0131] 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.

[0132] The preparation method of the composite unit described in the present invention is as follows (the part involving the structure is referred to as Figures 2 to 4 ):

[0133] The PPTC core material 1 is prepared by the above method or the prior art;

[0134] 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 composite unit.

[0135] In a specific embodiment, the electrode foil is a metal foil or a metal alloy foil.

[0136] 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 .

[0137] In one specific embodiment, the preparation method of the composite unit is:

[0138] 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;

[0139] 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;

[0140] 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;

[0141] 4) The structure formed in step 3) is cross-linked by electron beam irradiation with a irradiation dose of 50 Mrads to obtain a composite unit.

[0142] The preparation method of the multilayer PPTC element made of several composite units in the present invention is as follows (the part involving the structure is referred to as Figures 5 to 24 ):

[0143] The composite unit is prepared by the above method. According to the structural design of the multi-layer PPTC element, an insulating material is coated on the inner side of the epitaxial electrode to be bent to form an insulating part; further according to the structural design, the electrode layers of the two composite units are connected by welding and / or bonded by the insulating part formed by coating the insulating material; and the epitaxial electrode is further bent to form a first electrode connection surface or surface group 41, and then cut according to the required size (which can be achieved by punching, water jet cutting and cutting knife cutting), thereby preparing the multi-layer PPTC element. The welding method includes but is not limited to welding with solder paste 9.

[0144] In a specific embodiment, Figure 5-Figure 9As shown, when the multi-layer PPTC element is two stacked basic composite units 20, an insulating material is coated on the outside of the first composite part 21 of the two stacked basic composite units 20, an insulating material is coated on the inside of the bent part of the first epitaxial electrode 22 of the lower basic composite unit 20 and / or the second side 14 of the upper basic composite unit 20, and an insulating material is coated on the inside of the bent part of the first epitaxial electrode 22 of the upper basic composite unit 20 and / or the second side 14 of the lower basic composite unit 20 to form an insulating part (61, 62). The stacked part of the first epitaxial electrode 22 of the lower basic composite unit 20 and the second composite part 31 of the upper basic composite unit 20 and / or the stacked part of the first epitaxial electrode 22 of the upper basic composite unit 20 and the second composite part 31 of the lower basic composite unit 20 are both soldered by solder paste.

[0145] In a specific embodiment, Fig.10 As shown, when the multi-layer PPTC element is two stacked basic composite units 20, an insulating material is coated on the outside of the first composite part 21 of the two stacked basic composite units 20, an insulating material is coated on the entire inner side of the bend of the first epitaxial electrode 22 of the lower basic composite unit 20 and / or the second side 14 of the upper basic composite unit 20, and an insulating material is coated on the entire inner side of the bend of the first epitaxial electrode 22 of the upper basic composite unit 20 and / or the second side 14 of the lower basic composite unit 20 to form an insulating part (61, 62).

[0146] In a specific embodiment, Figure 11-Figure 14 As shown, when the multi-layer PPTC element is two stacked basic composite units 20, the outer surfaces of the first composite part 21 of the upper basic composite unit 20 and the second composite part 31 of the lower basic composite unit 20 are welded by solder paste, and the welding positions are at least 2; the inner side of the bent part of the first epitaxial electrode 22 of the lower basic composite unit 20 and / or the first side 13 of the lower basic composite unit 20 and the second side 14 of the upper basic composite unit 20 are coated with insulating material to form an insulating part (62); the entire inner side of the bent first epitaxial electrode 22 of the upper basic composite unit 20 and / or the second side 14 of the lower basic composite unit 20 and the outer surface of the first composite part 21 are coated with insulating material to form an insulating part (62, 63). And according to the structural design requirements, when the first epitaxial electrode 22 of the lower basic composite unit 20 and the second composite part 31 of the upper basic composite unit 20 are stacked, the stacked part is welded by solder paste.

[0147] In a specific embodiment, Figure 15-18As shown, when the multi-layer PPTC element is three stacked basic composite units, and the stacking method is an upper basic composite unit 30, a middle basic composite unit 10 and a lower basic composite unit 30, the outer surface between the second composite part 31 of the upper basic composite unit 30 and the second composite part 31 of the middle basic composite unit 10 is welded by solder paste, and there are at least two welding locations; the outer surface between the first composite part 21 of the middle basic composite unit 10 and the first composite part 21 of the lower basic composite unit 30 is welded by solder paste, and there are at least two welding locations. The first epitaxial electrode 22 of the middle-layer basic composite unit 10 is coated with an insulating material on the inner side of the bent part or the whole, and the first side 13 of the middle-layer basic composite unit 10 and the first side 13 of the upper-layer basic composite unit 30 on the same side may be coated with an insulating material to form an insulating portion (62) as needed; the second epitaxial electrode 32 of the middle-layer basic composite unit 10 is coated with an insulating material on the inner side of the bent part or the whole, and the second side 14 of the middle-layer basic composite unit 10 and the second side 14 of the lower-layer basic composite unit 30 on the same side may be coated with an insulating material to form an insulating portion (62) as needed. The first epitaxial electrode 22 of the middle-layer basic composite unit 10 and the first composite portion 21 of the upper-layer basic composite unit 30 and / or the second epitaxial electrode 32 of the middle-layer basic composite unit 10 and the second composite portion 31 of the lower-layer basic composite unit 30 are both soldered by solder paste.

[0148] In a specific embodiment, Fig.19As shown, when the multi-layer PPTC element is three stacked basic composite units, and the stacking method is an upper basic composite unit 20, a middle basic composite unit 20 and a lower basic composite unit 30, the outer surface between the first composite part 21 of the upper basic composite unit 20 and the second composite part 31 of the middle basic composite unit 20 is welded by solder paste, and the welding positions are at least 2; the outer surface between the first composite part 21 of the middle basic composite unit 20 and the first composite part 21 of the lower basic composite unit 30 is welded by solder paste, and the welding positions are at least 2. The first epitaxial electrode 22 of the middle basic composite unit 20 is coated with an insulating material on the inner side of the bent part or the whole, and the first side surface 13 of the middle basic composite unit 20 and the second side surface 14 of the upper basic composite unit 20 on the same side are coated with an insulating material to form an insulating portion (62) as needed; the first epitaxial electrode 22 of the upper basic composite unit 20 is coated with an insulating material on the inner side of the bent part or the whole, and the second side surface 14 of the middle basic composite unit 20 and the second side surface 14 of the lower basic composite unit 30 on the same side are coated with an insulating material to form an insulating portion (62) as needed. The stacked part of the first epitaxial electrode 22 of the middle basic composite unit 20 and the second composite part 21 of the upper basic composite unit 20 and / or the stacked part of the first epitaxial electrode 22 of the upper basic composite unit 20 and the second composite part 31 of the lower basic composite unit 30 are all soldered by solder paste.

[0149] In a specific embodiment, Figure 20-24 As shown, when the multilayer PPTC component is five stacked basic composite units, and the stacking method is an upper basic composite unit 20, a first intermediate basic composite unit 20, a second intermediate basic composite unit 10, a third intermediate basic composite unit 20 and a lower basic composite unit 20, according to the same concept as the above-mentioned three-stacked composite unit preparation method, soldering is performed on the outer surface of the electrode layer portion of two adjacent basic composite units stacked by solder paste, and the soldering positions are at least 2; the inner side of the bending of each epitaxial electrode to be bent and the side stacking portion of each basic composite unit are coated with insulating material to form an insulating portion (62), and each epitaxial electrode is soldered with the outer electrode of the outermost basic composite unit when stacked. The specific portion and method of coating the insulating material and the welding position and method can all refer to the preparation of the multilayer plug-in PPTC component formed based on multiple basic review units 10, and will not be repeated here.

[0150] In a specific embodiment, the PPTC core materials 1 of the multiple composite units 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.

[0151] Next, based on the above overall description, we will further combine Figures 5 to 24 Compound units as well as double-layer, triple-layer and five-layer PPTC components are exemplified.

[0152] Example 1

[0153] refer to Figure 2 In the first composite unit 10 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 22, 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 32, and the second side surface 14 and the first side surface 13 are arranged opposite to each other.

[0154] In this embodiment, the end of the first electrode layer 2 opposite to the first epitaxial electrode 22 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 22 may also be slightly narrower than the PPTC core material 1.

[0155] Of course, the edge positions of the first electrode layer 2 except the first epitaxial electrode 22 can be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1 .

[0156] 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 .

[0157] Of course, the edge positions of the second electrode layer 3 except the second epitaxial electrode 32 can be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1 .

[0158] Example 2

[0159] refer to Figure 3 The difference between the second composite unit 20 provided in this embodiment and that provided in Embodiment 1 is that the second composite unit 20 in this embodiment does not include the second epitaxial electrode 32. In order to more clearly reflect the technical solution of this embodiment, the following is combined with Figure 3 Detailed description.

[0160] In the second composite unit 20 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 22, and the end of the first electrode layer 2 opposite to the first epitaxial electrode 22 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 22 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 22 may be set to be flush with the PPTC core material 1 or slightly narrower than the edge of the PPTC core material 1.

[0161] In this embodiment, the end of the second electrode layer 3 on the same side as the first epitaxial electrode 22 is flush with the PPTC core material 1, and the end opposite to the first epitaxial electrode 22 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.

[0162] Example 3

[0163] refer to Figure 4 In the third composite unit 30 provided in this embodiment, the first electrode layer 2 is flush with the periphery of the PPTC core material 1 or slightly retracted relative to the PPTC core material 1. Obviously, the first electrode layer 2 does not have an epitaxial electrode extending from the first side 13 and the second side 14. Similarly, the second electrode layer 3 is flush with the periphery of the PPTC core material 1 or slightly retracted relative to the PPTC core material 1. Obviously, the second electrode layer 3 does not have an epitaxial electrode extending from the first side 13 and the second side 14.

[0164] Example 4

[0165] refer to Figure 5 The double-layer PPTC element provided in this embodiment has a main structure made of two second composite units 20 , and accordingly, the second composite units 20 are stacked to produce two first epitaxial electrodes 22 located on opposite sides.

[0166] Two first electrode layers 2 with first epitaxial electrodes 22 are bonded between two PPTC core materials 1 through a first insulating portion 61. One of the first epitaxial electrodes 22 is bent upward along the side of the PPTC core material 1, and a second insulating portion 62 is provided between the side of the PPTC core material 1, and then further bent and fixed to the second electrode layer 3 at the first surface or surface group 51 by solder paste 9, and the two correspond to the first electrode connection surface or surface group 41, and the part of the second electrode layer 3 located on the first surface or surface group 51 that is not covered by the epitaxial electrode is the first electrode connection surface or surface group 41. The other first epitaxial electrode 22 is bent downward along the side of the PPTC core material 1 and a second insulating portion 62 is provided between the side of the PPTC core material 1, and then further bent and fixed to the second electrode layer 3 at the second surface 52 by solder paste 9, and the two correspond to the second electrode connection surface or surface group 42, and the part of the second electrode layer 3 located on the second surface 52 that is not covered by the epitaxial electrode is the second electrode connection surface or surface group 42.

[0167] The first electrode member 71 and the second electrode member 72 are respectively sheet-shaped electrodes, such as Figure 6 As shown, the left side of the first electrode member 71 is close to or attached to the outermost layer of the epitaxial electrode, and a first extension portion 73 is formed on the right side, and the right side of the second electrode member 72 is close to or attached to the outermost layer of the epitaxial electrode, and a second extension portion 74 is formed on the left side, thereby forming a double-layer strip PPTC element. An encapsulation structure can also be further provided to wrap the surface with an insulating material, with only two extension portions exposed.

[0168] Example 5

[0169] refer to Figure 7 The double-layer PPTC element provided in this embodiment has a main structure made of two second composite units 20 , and accordingly, the second composite units 20 are stacked to produce two first epitaxial electrodes 22 located on opposite sides.

[0170] Two first electrode layers 2 with first epitaxial electrodes 22 are bonded between two PPTC core materials 1 through a first insulating portion 61. One of the first epitaxial electrodes 22 is bent upward along the side of the PPTC core material 1, and a second insulating portion 62 is provided between the side of the PPTC core material 1, and then further bent and fixed to the second electrode layer 3 at the first surface or surface group 51 by solder paste 9, and the two correspond to the first electrode connection surface or surface group 41, and the part of the second electrode layer 3 located on the first surface or surface group 51 that is not covered by the epitaxial electrode is the first electrode connection surface or surface group 41. Another first epitaxial electrode 22 is bent downward along the side of the PPTC core material 1, and a second insulating portion 62 is provided between the side of the PPTC core material 1, and the end face of the first epitaxial electrode 22 is flush with the surface of the second electrode layer 3 located on the second surface 52, and the surface of the second electrode layer 3 located on the second surface 52 forms a first region 43, and the end face of the first epitaxial electrode 22 forms a second region 44, and the two together form the second electrode connection surface or surface group 42.

[0171] The first electrode member 71 and the second electrode member 72 can be respectively provided with lead wires. Figure 7 The right side of the device is extended to form a first extension portion 73 and a second extension portion 74, thereby forming a double-layer plug-in type PPTC component.

[0172] In another embodiment, Figure 8 As shown, on the basis of embodiment 5, a packaging structure 8 is further provided, and the surface is wrapped with insulating material, with only two protruding parts exposed.

[0173] Example 6

[0174] refer to Fig. 9 This embodiment provides a double-layer PPTC element, which is different from the embodiment 5 in the form of the electrode member and its relationship with the main structure. Specifically, the first electrode member 71 and the second electrode member 72 are sheet electrodes, and the first extension 73 and the second extension 74 are located on opposite sides of the main structure. The other parts of this other embodiment are the same as those of the embodiment 5, thereby forming a double-layer strip-shaped PPTC core material 1.

[0175] Example 7

[0176] refer to Fig.10Understand. This embodiment provides a double-layer PPTC element, which is different from the embodiment 5 in the form of the first electrode connection surface or surface group 41, the form of the electrode component and its relationship with the main structure. Specifically, the first epitaxial electrode 22 is bent upward to be flush with the surface of the electrode layer located on the first surface or surface group 51, so that its outermost layer forms the second area 44, and the electrode layer located on the first surface or surface group 51 forms the first area 43. The first electrode component 71 and the second electrode component 72 are sheet electrodes, and the periphery of the two is aligned with the side of the main structure. The other parts of this another embodiment are the same as those of the embodiment 5, thereby forming a double-layer terminal type PPTC element.

[0177] Example 8

[0178] refer to Fig.11 The double-layer PPTC element provided in this embodiment has a main structure made of two second composite units 20 , and accordingly, the second composite units 20 are stacked to produce two first epitaxial electrodes 22 located on opposite sides.

[0179] After stacking, the two first electrode layers 2 with the first epitaxial electrode 22 are respectively located at the second surface 52 and between the two PPTC core materials 1. The first epitaxial electrode 22 located at the second surface 52 is first bent upward along the side of the PPTC core material 1, and a second insulating portion 62 is provided between the first epitaxial electrode 22 and the side of the PPTC core material 1, and then further bent and fixed to the second electrode layer 3 located at the first surface or surface group 51 by solder paste 9. The uncovered portion of the second electrode layer 3 located at the first surface or surface group 51 forms the first electrode connection surface or surface group 41. The first epitaxial electrode 22 located between the two PPTC core materials 1 is first bent downward along the side of the PPTC core material 1, and a second insulating portion 62 is provided between the first epitaxial electrode 22 and the side of the PPTC core material 1, and then further bent and completely covered the first composite portion 21 located at the second surface 52, and a third insulating portion 63 is provided between the first composite portion 21 for electrical isolation, and the second electrode connection surface or surface group 42 is formed by the epitaxial electrode.

[0180] In this embodiment, the first electrode member 71 and the second electrode member 72 may be sheet electrodes, such as Fig.12 As shown, after the main structure is connected, two extension parts extending in opposite directions are formed, thereby forming a double-layer strip-shaped PPTC element. In this embodiment, an encapsulation structure 8 can be further provided.

[0181] In another embodiment, the difference from the embodiment 8 lies in the electrode components and their relationship with the main structure. Specifically, the first electrode component 71 and the second electrode component 72 are wires, such as Fig.13As shown, after connecting the main structures, two extension parts with the same extension direction are formed; the other parts of this other embodiment are the same as those of embodiment 8, thereby forming a double-layer plug-in type PPTC component.

[0182] In another embodiment, the difference from the embodiment 8 lies in the form of the electrode connection surface or surface group and the relationship between the electrode component and the main structure: the first epitaxial electrode 22 located at the second surface 52 is bent toward the first surface or surface group 51 to form the second region 44, the surface of the second electrode layer 3 located at the first surface or surface group 51 forms the first region 43, and the first electrode component 71 and the second electrode component 72 are sheet electrodes, such as Fig.14 As shown, after installation, the peripheries of the two sheet electrodes are aligned with the side surfaces of the main structure, and the other parts of this another embodiment are the same as those of Embodiment 8, thereby forming a double-layer terminal type PPTC component.

[0183] Example 9

[0184] refer to Fig.15 The three-layer PPTC component provided in this embodiment has a main structure made of a first composite unit 10 and two third composite units 30 , the first composite unit 10 is located between the two third composite units 30 , and adjacent composite units are fixed by soldering with solder paste 9 .

[0185] After the three composite units are stacked, the first electrode layer 2 is located at the lower layer of the composite unit, and the second electrode layer 3 is located at the upper layer of the first composite unit 10. Obviously, relatively speaking, at this time, the first epitaxial electrode 22 is closer to the second surface 52, and the second epitaxial electrode 32 is closer to the first surface or surface group 51.

[0186] The first epitaxial electrode 22 is first bent upward from a position close to the second surface 52, and is isolated from the side surfaces of the two PPTC core materials 1 by the second insulating portion 62, and then is further bent to be fixed to the first electrode layer 2 located at the first surface or surface group 51 by solder paste 9. The second epitaxial electrode 32 is first bent downward from a position close to the first surface or surface group 51, and is isolated from the side surfaces of the two PPTC core materials 1 by the second insulating portion 62, and then is further bent to be fixed to the second electrode layer 3 located at the second surface 52 by solder paste 9.

[0187] In this embodiment, the first electrode member 71 and the second electrode member 72 are sheet-shaped electrodes, such as Fig.16 As shown, after the two are connected to the main structure, the first protruding portion 73 and the second protruding portion 74 are located on opposite sides of the main structure, thereby forming a three-layer strip-shaped PPTC element.

[0188] In another embodiment, the difference from the embodiment 9 lies in the form of the electrode connection surface or surface group, the form of the electrode component and the relationship between the electrode component and the main structure. Specifically, the first epitaxial electrode 22 is bent to form the second region 44, the surface of the electrode layer of the first surface or surface group 51 forms the first region 43, and the first electrode component 71 and the second electrode component 72 are wired, such as Fig.17 As shown, after installation, a first protruding portion 73 and a second protruding portion 74 are formed on the same side of the main structure, and the other parts of this another embodiment are the same as those of Embodiment 9, thereby forming a three-layer plug-in type PPTC component.

[0189] In another embodiment, the difference from Embodiment 9 lies in the form of the electrode connection surface or surface group, the form of the electrode component, and the relationship between the electrode component and the main structure. Specifically, the first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42 respectively use non-continuous surfaces composed of multiple surfaces. The first epitaxial electrode 22 is bent to form a second region 44, and the surface of the electrode layer of the first surface or surface group 51 forms a first region 43. Similarly, the second epitaxial electrode 32 is bent to form another second region 44, and the surface of the electrode layer of the second surface 52 forms another first region 43. The first electrode component 71 and the second electrode component 72 use sheet electrodes, such as Fig.18 As shown, after installation, the peripheries of the first electrode member 71 and the second electrode member 72 are aligned with the side surfaces of the main structure, thereby forming a three-layer terminal type PPTC element.

[0190] Example 10

[0191] refer to Fig.19 The three-layer PPTC component provided in this embodiment has a main structure made of a second composite unit 20, a second composite unit 20 and a third composite unit 30 arranged in sequence, and adjacent composite units are fixed by soldering with solder paste 9.

[0192] After the three composite units are stacked, one of the first epitaxial electrodes 22 is first bent upward, and a second insulating portion 62 is set between the side surface of the PPTC core material 1, and then it is further bent and fixed to the electrode layer at the first surface or surface group 51 by solder paste 9, and the uncovered portion of the electrode layer on the first surface or surface group 51 forms a first electrode connection surface or surface group 41; the other first epitaxial electrode 22 is first bent downward, and a second insulating portion 62 is set between the side surface of the PPTC core material 1, and then it is further bent and fixed to the electrode layer at the second surface 52 by solder paste 9, and the uncovered portion of the electrode layer on the second surface 52 forms a second electrode connection surface or surface group 42.

[0193] In this embodiment, the first electrode member and the second electrode member are sheet electrodes. After the two are connected to the main structure, the first extension part and the second extension part are located on opposite sides of the main structure, thereby forming a three-layer strip PPTC element.

[0194] In another embodiment, the difference from Embodiment 10 lies in the form of the electrode connection surface or surface group, the form of the electrode component and the relationship between the electrode component and the main structure. Specifically, the first epitaxial electrode is bent to form the second area, the surface of the electrode layer of the first surface or surface group forms the first area, the first electrode component and the second electrode component use leads, and after installation, the first extension part and the second extension part are formed on the same side of the main structure. The other parts of this other embodiment are the same as those of Embodiment 9, thereby forming a three-layer plug-in PPTC element.

[0195] In another embodiment, the difference from Embodiment 10 lies in the form of the electrode connection surface or surface group, the form of the electrode component, and the relationship between the electrode component and the main structure. Specifically, the first electrode connection surface or surface group and the second electrode connection surface or surface group respectively adopt non-continuous surfaces composed of multiple surfaces, and the first epitaxial electrode is bent to form a second area, and the surface of the electrode layer of the first surface or surface group forms a first area. Similarly, the second epitaxial electrode is bent to form another second area, and the surface of the electrode layer of the second surface forms another first area. The first electrode component 71 and the second electrode component adopt sheet electrodes. After installation, the peripheries of the first electrode component and the second electrode component are aligned with the sides of the main structure, respectively, thereby forming a three-layer terminal type PPTC element.

[0196] Embodiment 11

[0197] refer to Fig. 20 Understand. The five-layer PPTC component provided in this embodiment, from the first surface or surface group 51 to the second surface 52, the composite units are respectively the second composite unit 20, the second composite unit 20, the first composite unit 10, the second composite unit 20 and the second composite unit 20; the electrode layers between adjacent PPTC core materials 1 are welded and fixed; after each composite unit is stacked, the first side 53 and the second side 54 have three epitaxial electrodes respectively. Among the three epitaxial electrodes on the same side, the electrode layers corresponding to two of the epitaxial electrodes are located between the two PPTC core materials 1, and the two epitaxial electrodes are bent in opposite directions, and the other epitaxial electrode is bent from a position close to one end of the multi-layer PPTC component and partially covers the electrode layer located at the other end of the multi-layer PPTC component.

[0198] like Fig.21As shown, the first electrode member 71 and the second electrode member 72 are sheet electrodes, and the first extension 73 and the second extension 74 formed after the two are installed on the main structure are located on opposite sides of the main structure, thereby forming a five-layer strip PPTC core material 1. This embodiment can further provide an encapsulation structure 8.

[0199] In another embodiment, the difference from the embodiment 11 lies in the form of the electrode connection surface or surface group, the form of the electrode member, and the relationship between the electrode member and the main structure. Specifically, the epitaxial electrode located on the first side 53 is bent to form the second region 44, the surface of the electrode layer of the first surface or surface group 51 forms the first region 43, and the first electrode member 71 and the second electrode member 72 are wired, such as Fig. 22 As shown, after installation, two protrusions are formed on the same side of the main structure, and the other parts of this another embodiment are the same as those of embodiment 11, thereby forming a five-layer plug-in type PPTC component.

[0200] In another embodiment, the difference from Embodiment 11 lies in the form of the electrode connection surface or surface group, the form of the electrode component, and the relationship between the electrode component and the main structure. Specifically, the first electrode connection surface or surface group 41 and the second electrode connection surface or surface group 42 respectively adopt non-continuous surfaces composed of multiple surfaces, and the two upwardly bent epitaxial electrodes located on the first side 53 form the second region 44, and the surface of the electrode layer located on the first surface or surface group 51 forms a first region 43, and the first region 43 and the second region 44 jointly form the first connection surface. Similarly, the two downwardly bent epitaxial electrodes located on the second side 54 form the second region 44, and the surface of the electrode layer located on the second surface 52 forms a first region 43, and the first region 43 and the second region 44 jointly form the second connection surface; the first electrode component 71 and the second electrode component 72 adopt sheet electrodes, such as Fig.23 As shown, after installation, the peripheries of the first electrode member 71 and the second electrode member 72 are aligned with the side surfaces of the main structure, thereby forming a five-layer terminal type PPTC element.

[0201] Example 12

[0202] refer to Fig.24 The five-layer PPTC element provided in this embodiment is different from that in Embodiment 11 in that the second composite unit from the first surface or surface group 51 in this embodiment adopts the third composite unit 30, and accordingly, after each composite unit is stacked, there are two electrically connected epitaxial electrodes at the first side 53, one of which is bent downward, and the other is bent upward and fixed to the electrode layer at the first surface or surface group 51 by solder paste 9. The other parts of this embodiment are the same as those in Embodiment 11, and will not be repeated here.

[0203] Combined with the above technical information, it can be known that the multilayer PPTC component provided by the present invention can be used to produce plug-in type, terminal type and strip type, solving the problem that the prior art cannot produce multilayer plug-in type, multilayer terminal type and multilayer strip PPTC products. Specifically, the multilayer PPTC component is made of composite units. After each composite unit is stacked, the first side 53 and the second side 54 both have epitaxial electrodes. The epitaxial electrodes are processed so that each PPTC core material 1 is connected in parallel, and a first electrode connection surface or surface group 41 and a second electrode connection surface or surface group 42 are formed. The two electrode connection surfaces or surface groups can cooperate with the lead electrode and the sheet electrode to form a multilayer plug-in type PPTC component, a multilayer terminal type PPTC component and a multilayer strip type PPTC component, and the production steps are simple and easy to operate.

[0204] It is important to emphasize that:

[0205] First, in the prior art, the production process and production equipment of plug-in PPTC components, terminal PPTC components and strip PPTC components are all based on PPTC substrates. Due to the maturity of the production process and production line, the PPTC substrate is always in the form of flush sides. Improving the PPTC substrate involves process adjustment and the resulting production line adjustment. People are accustomed to producing according to the existing technology. Subject to the existing production process, production line and people's inertial thinking, no one has ever proposed to produce a multilayer structure by deforming the PPTC substrate; but the present invention is based on composite units. In several composite units, there are at least two epitaxial electrodes. By bending the epitaxial electrodes and setting the relationship between the electrode layers, the parallel connection between the PPTC core materials 1 is realized. Among them, the process of composite units with epitaxial electrodes is different from the existing process, and the various processes involved in stacking the composite units and the process of connecting the composite units are also different from the existing technology. In other words, the present invention breaks through the limitations of traditional production processes and breaks inertial thinking.

[0206] Second, the present invention is a huge breakthrough in business. The multi-layer plug-in PPTC components, multi-layer terminal PPTC components and multi-layer strip PPTC components generated by the composite unit 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, which shows that the commercial value is huge.

[0207] Third, by setting the formula and thickness relationship of each PPTC core material 1, different holding currents and rated voltages can be obtained, thereby obtaining products with different safety levels.

[0208] 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 multi-layer PPTC component, characterized in that: It is made on the basis of several composite units; the composite unit includes a PPTC core material and electrode layers arranged on two surfaces of the PPTC core material, and when the electrode layer extends out of the PPTC core material, the extended part is an epitaxial electrode; The multilayer PPTC element has two electrode connection surfaces or surface groups, which are a first electrode connection surface or surface group located on the first surface or surface group and a second electrode connection surface or surface group located on the second surface; After each of the composite units is stacked, the first side and the second side of the multilayer PPTC element each have at least one epitaxial electrode, wherein the first side and the second side are arranged opposite to each other; The epitaxial electrode is bent so that: one electrode layer in each of the composite units is electrically connected to each other and forms the first electrode connection surface or surface group, or can be electrically connected through a conductor at the first electrode connection surface or surface group, and another electrode layer in each of the composite units is electrically connected to each other and forms the second electrode connection surface or surface group, or can be electrically connected through a conductor at the second electrode connection surface or surface group; When the epitaxial electrode is bent, the electrode layer corresponding to the first electrode connection surface or surface group is electrically isolated from the electrode layer corresponding to the second electrode connection surface or surface group.

2. The multi-layer PPTC component according to claim 1, characterized in that: The two electrode layers between adjacent PPTC core materials are fixed by welding and electrically connected, or bonded by insulating materials and electrically isolated.

3. The multi-layer PPTC component according to claim 1, characterized in that: At least part of the side surfaces of the PPTC core material are provided with insulating material to electrically isolate the bent epitaxial electrode.

4. The multi-layer PPTC component according to claim 1, characterized in that: At least one of the electrode connection surfaces or surface groups is arranged continuously, and the continuously arranged electrode connection surfaces or surface groups are realized by any of the following methods: (1) The epitaxial electrode partially covers the electrode layer located at the outermost layer of the multi-layer PPTC component and is electrically connected thereto, and the portion of the electrode layer located at the outermost layer of the multi-layer PPTC component that is not covered by the epitaxial electrode forms an electrode connection surface or surface group; (2) The epitaxial electrode covers the electrode layer located at the outermost layer of the multi-layer PPTC element and is insulated and connected thereto. The coverage area of ​​the epitaxial electrode extends from the first side to the second side, and the surface of the coverage area forms an electrode connection surface or surface group.

5. The multi-layer PPTC component according to claim 1, characterized in that: At least one of the electrode connection surfaces or surface groups includes a first region and a second region that are intermittently arranged, wherein the electrode connection surface or surface group is realized by any of the following methods: (1) The first region is formed by an electrode layer located at the outermost layer of the multi-layer PPTC element and composited on the PPTC core material, and the second region is formed by bending the epitaxial electrode to be flush with the electrode layer; (2) The first region is formed by an electrode layer located at the outermost layer of the multi-layer PPTC element and composited on the PPTC core material, the portion of the epitaxial electrode covering the electrode layer is a covering portion, and the second region is a surface of the covering portion.

6. The multi-layer PPTC component according to claim 1, characterized in that: The multilayer PPTC element is made of a plurality of second composite units, or is made of the first composite unit and the third composite unit, or is made of the second composite unit and the third composite unit, or is made of the first composite unit, the second composite unit and the third composite unit; Among them, in the first composite unit, each of the two electrode layers has one epitaxial electrode, and the two epitaxial electrodes are located on opposite sides of the PPTC core material; the second composite unit has only one epitaxial electrode; in the third composite unit, the peripheries of the two electrode layers do not extend out of the PPTC core material.

7. The multi-layer PPTC component according to claim 6, characterized in that: There are two composite units, both of which use the second composite unit, wherein: The electrode layer having the epitaxial electrode is bonded between two PPTC core materials through an insulating material, wherein one epitaxial electrode and the electrode layer at the first surface or surface group correspond to the first electrode connection surface or surface group, and the other epitaxial electrode and the electrode layer at the second surface correspond to the second electrode connection surface or surface group; or After stacking, the two electrode layers with epitaxial electrodes are respectively located between the second surface and the two PPTC core materials, wherein the epitaxial electrode located on the second surface and the electrode layer located on the first surface or surface group correspond to the first electrode connection surface or surface group, and the epitaxial electrode located between the two PPTC core materials is bent to the second surface and extends from the first side to the second side.

8. The multi-layer PPTC component according to claim 6, characterized in that: There are three composite units, one of which is the first composite unit, and the other two are the third composite units, wherein: The first composite unit is arranged between two third composite units, the electrode layers between adjacent PPTC core materials are welded and fixed, one epitaxial electrode is bent to partially cover the electrode layer located on the first surface or surface group and is electrically connected thereto, and the other epitaxial electrode is bent to partially cover the electrode layer located on the second surface and is electrically connected thereto.

9. The multi-layer PPTC component according to claim 6, characterized in that: From the first surface or surface group to the second surface, the composite units respectively adopt the second composite unit, the second composite unit, the first composite unit, the second composite unit and the second composite unit; the electrode layers between adjacent PPTC core materials are welded and fixed; Among the three epitaxial electrodes located on the same side, the electrode layers corresponding to two of the epitaxial electrodes are located between the two PPTC core materials, and the two epitaxial electrodes are bent in opposite directions, and the other epitaxial electrode is bent from a position close to one end of the multi-layer PPTC component and partially covers the electrode layer located at the other end of the multi-layer PPTC component.

10. The multi-layer PPTC component according to claim 1, characterized in that: The multilayer PPTC element further includes a first electrode member and a second electrode member; The first electrode member is fixed on the first electrode connection surface or surface group and forms an electrical connection relationship with the electrode layer corresponding to the first electrode connection surface or surface group; The second electrode component is fixed on the second electrode connection surface or surface group, and forms an electrical connection relationship with the electrode layer corresponding to the second electrode connection surface or surface group.

11. The multi-layer PPTC component according to claim 10, characterized in that: The first electrode member and the second electrode member are respectively in sheet shape, and the periphery of the first electrode member and the periphery of the second electrode member do not extend out of the side surface of the multi-layer PPTC element.

12. The multi-layer PPTC component according to claim 10, characterized in that: One side of the first electrode component extends out relative to each of the PPTC core materials to form a first extension portion, and one side of the second electrode component extends out relative to each of the PPTC core materials to form a second extension portion.

13. The multi-layer PPTC component according to claim 12, characterized in that: The first electrode member and the second electrode member use lead wires, and the first protruding portion and the second protruding portion are located on the same side.

14. The multi-layer PPTC component according to claim 12, characterized in that: The first electrode member and the second electrode member are electrode sheets, and the first protruding portion and the second protruding portion are located on opposite sides.

15. The multi-layer PPTC component according to any one of claims 12 to 13, characterized in that: The surface of the multi-layer PPTC element is wrapped with an encapsulation structure, and the first protruding portion and the second protruding portion extend out of the encapsulation structure.

16. The multi-layer PPTC component according to any one of claims 1 to 14, characterized in that: The PPTC core materials have the same thickness, or the thickness of at least one PPTC core material is different from the thickness 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.

17. A method for preparing a multilayer PPTC component according to any one of claims 1 to 16, characterized in that: The steps include: A1. Prepare PPTC core material; A2. Electrode foils are respectively composited on the upper and lower surfaces of the PPTC core material to form electrode layers, and then irradiated and cross-linked by electron beam or cobalt 60, with an irradiation dose of 1 to 100 Mrads, thereby preparing the desired composite unit; A3. An insulating material is disposed on the inner side of the epitaxial electrode. After the composite units are stacked, the epitaxial electrodes on the same side are bent to form the first electrode connection surface or surface group and the second electrode connection surface or surface group.

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