High-reliability over-current protection device capable of improving voltage resistance level

Abstract

The utility model relates to the technical field of over-current protection devices, in particular to a high-reliability over-current protection device capable of improving voltage resistance level, which comprises a packaging layer, and at least two over-current protection components are arranged in the packaging layer along the horizontal direction. The adjacent over-current protection assemblies are connected in series through an upper electrode arranged above the over-current protection assemblies or a lower electrode arranged below the over-current protection assemblies to form a current path. In order to solve the problems that an overcurrent protection element in the prior art is limited by material characteristics, the applicable current range is narrow or heat is easy to accumulate, at least two overcurrent protection assemblies are arranged in a packaging layer in the horizontal direction and are connected in series through electrodes located on the upper portion or the lower portion. The overall current resistance is improved by connecting multiple groups of assemblies in series, and meanwhile, a larger packaging surface area is obtained through a planar device, so that the heat accumulation problem during normal use can be relieved.

Description

Technical Field

[0001] The utility model relates to the technical field of overcurrent protection devices, and in particular to a high-reliability overcurrent protection device with an improved voltage resistance level. Background Art

[0002] Overcurrent protection devices are circuit protection components commonly used in various electronic circuits. When an overcurrent fault occurs in the circuit, these devices will fuse or perform other operations to disconnect the circuit, thereby preventing the risk of overcurrent damage. Typically, this fusing process is achieved using a protection element with a positive temperature coefficient. These elements are primarily made of materials whose resistance is proportional to temperature. When an overcurrent occurs, the material's resistance increases sharply, causing heat and melting, thereby protecting the circuit.

[0003] For example, Chinese patent CN201610553351.4 provides an overcurrent protection element, which includes a PTC material layer with a positive temperature coefficient characteristic, a first conductive layer, a second conductive layer, a first electrode, a second electrode, a first electrical connector, a second electrical connector, and at least one insulating layer. In the PTC material layer, the volume fraction of the polymer is 30% to 60%, the volume fraction of the conductive filler is 40% to 70%, and the volume resistivity is less than 0.01Ω.cm. The first and second conductive layers are respectively attached to the first and second surfaces of the PTC material layer. The first and second electrodes are electrically connected to the first and second conductive layers, respectively, and the insulating layer is disposed between the first and second electrodes. The first and second electrical connectors use a polymer-based conductive composite material instead of conductive vias, which increases the current-carrying area and reduces the area of ​​contact between the element and air, thus giving the overcurrent protection element a large current-carrying capacity and excellent weather resistance.

[0004] However, during the actual implementation process, the inventors found that since this type of material is made based on sheet-shaped positive temperature coefficient material, it has a specific thickness range, which restricts the current range to which the material can be applied; if multiple groups of materials are stacked and connected in series, it will cause a large heat accumulation problem during use. Utility Model Content

[0005] In view of the above problems existing in the prior art, a high-reliability overcurrent protection device with improved voltage resistance is provided.

[0006] The specific technical solutions are as follows:

[0007] A high-reliability overcurrent protection device with improved voltage resistance, the high-reliability overcurrent protection device comprising a packaging layer, wherein at least two overcurrent protection components are arranged in a horizontal direction in the packaging layer;

[0008] Adjacent overcurrent protection components are connected in series by arranging an upper electrode above the overcurrent protection component or a lower electrode below the overcurrent protection component to form a current path.

[0009] On the other hand, conductive pads are respectively provided at the bottom of the overcurrent protection component located at the first stage and the bottom of the overcurrent protection component located at the last stage.

[0010] On the other hand, the overcurrent protection component includes:

[0011] a first electrode foil;

[0012] a conductive composite material core material, wherein the conductive composite material core material is located above the first electrode foil;

[0013] A second electrode foil is located above the conductive composite material core.

[0014] On the other hand, the upper electrode is formed on the upper surface of the encapsulation layer.

[0015] On the other hand, the lower electrode is buried in the packaging layer.

[0016] On the other hand, the lower electrode is formed on the lower surface of the encapsulation layer.

[0017] On the other hand, a sealing layer is provided between adjacent overcurrent protection components;

[0018] The sealing layer is arranged along a vertical direction.

[0019] On the other hand, a solder resist layer is provided on the lower surface of the sealing layer.

[0020] On the other hand, the upper electrode and the lower electrode are electrically connected to the overcurrent protection component through conductive through-holes.

[0021] On the other hand, the number of the overcurrent protection components is 2 or 4.

[0022] The above technical solution has the following advantages or beneficial effects:

[0023] In order to address the problem that the overcurrent protection elements in the existing technology are restricted by material properties, have a narrow applicable current range or are prone to heat accumulation, in this solution, at least two overcurrent protection components are arranged horizontally in the packaging layer and are connected in series through electrodes located above or below. By connecting multiple groups of components in series, the overall current resistance performance is improved. At the same time, a larger packaging surface area is obtained through planar devices, which helps to alleviate the heat accumulation problem during normal use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The embodiments of the present invention will be described more fully with reference to the accompanying drawings, which are for illustration and description only and are not intended to limit the scope of the present invention.

[0025] Figure 1 This is a schematic diagram of the first embodiment of the present utility model;

[0026] Figure 2 This is a schematic diagram of the second embodiment of the present utility model;

[0027] Figure 3 This is a schematic diagram of the third embodiment of the present utility model; DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0031] The utility model includes:

[0032] A high-reliability overcurrent protection device with improved voltage resistance, see Figure 1-3 As shown, the high reliability overcurrent protection device includes a packaging layer 1, in which at least two overcurrent protection components 2 are arranged in a horizontal direction;

[0033] Adjacent overcurrent protection components 2 are connected in series via an upper electrode 3 disposed above the overcurrent protection component 2 or a lower electrode 4 disposed below the overcurrent protection component 2 to form a current path.

[0034] Specifically, in order to address the problem that the overcurrent protection elements in the prior art are restricted by material properties, have a narrow applicable current range or are prone to heat accumulation, in this solution, at least two overcurrent protection components 2 are arranged horizontally in the packaging layer 1, and are connected in series through electrodes located above or below. By connecting multiple groups of overcurrent protection components 2 in series, the overall current resistance performance is improved. At the same time, a larger packaging surface area is obtained through planar devices, which helps to alleviate the heat accumulation problem during normal use.

[0035] Specifically, conductive pads 5 are provided at the bottom of the first-stage overcurrent protection assembly 2 and the last-stage overcurrent protection assembly 2, respectively. The conductive pads 5 are located below and exposed from the packaging layer 1. In actual use, the conductive pads 5 are connected to external circuit pads via reflow soldering or other equivalent soldering methods to form an electrical connection.

[0036] Above the conductive pad 5, it is connected to the first-stage overcurrent protection component 2 and the bottom of the last-stage overcurrent protection component 2 through the conductive through-hole 6. Figure 1 Taking the embodiment with two overcurrent protection components 2 shown as an example, the top of the conductive pad 5 is connected to the bottom of the first-level overcurrent protection component 2 through the conductive through-hole 6, and then the top of the first-level overcurrent protection component 2 is connected to the upper electrode 3 above through the conductive through-hole 6. The upper electrode 3 is connected to the top of the second-level overcurrent protection component 2 through the conductive through-hole 6 below after a certain distance, and then connected to the conductive pad 5 below through the conductive through-hole 6 at the bottom of the second-level overcurrent protection component 2.

[0037] Among them, the conductive pad 5 is formed by chemical deposition, spraying, sputtering, electroplating or a combination of these processes, and is formed by preparing a specific material at the bottom of the sealing layer 1 according to the above process. The specific material is composed of one of zinc, copper, nickel, cobalt, iron, tungsten, tin, lead, silver, gold, platinum or their alloys and a mixture thereof.

[0038] Furthermore, the conductive through hole 6 is one or a combination of two or more of a laser hole and a buried hole. The laser hole refers to an interconnected hole formed by ablating the packaging layer 1 through a laser ablation process and then attaching a conductive metal layer to the surface of the hole.

[0039] The buried via is drilled by mechanical drilling or burned by laser, and a conductive metal layer is attached to the surface of the hole. The shape of the conductive through hole 6 can be any regular or irregular shape.

[0040] At the same time, the conductive through hole 6 can be a layer of conductive metal attached to the hole wall, or the hole can be completely filled with conductive metal by filling the hole with electroplating, or the hole can be filled with plugging material using plugging technology.

[0041] When using plugging technology, one or a combination of epoxy resin, phenolic resin, glass fiber or inorganic filler modified epoxy resin, glass fiber or inorganic filler modified phenolic resin should be selected as the plugging material.

[0042] In one embodiment, the overcurrent protection component 2 includes:

[0043] First electrode foil 21;

[0044] A conductive composite material core material 22 , the conductive composite material core material 22 is located above the first electrode foil 21 ;

[0045] The second electrode foil 23 is located above the conductive composite material core 22 .

[0046] Specifically, to achieve a better positive temperature coefficient control effect, in this embodiment, the above-mentioned structure is prepared to clamp the conductive composite core material 22 having positive temperature coefficient characteristics. The conductive composite core material 22 is made of a composite material having a positive temperature coefficient effect, with a volume resistivity distribution of 0.001 to 10 Ω·m, and is primarily composed of a mixture of polymer and conductive filler.

[0047] Among them, the volume fraction of the polymer in the conductive composite material base layer is between 20% and 75%, and is selected from one of polyethylene, chlorinated polyethylene, oxidized polyethylene, polyvinyl chloride, butadiene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, polystyrene, polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, polyphenylene sulfide, polyformaldehyde, phenolic resin, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polytrifluoroethylene, polyvinyl fluoride, maleic anhydride grafted polyethylene, polypropylene, polyvinylidene fluoride, epoxy resin, ethylene-vinyl acetate copolymer, polymethyl methacrylate, ethylene-acrylic acid copolymer and a mixture thereof.

[0048] The conductive filler is selected from one of carbon black, graphite, carbon fiber, carbon nanotubes, metal powder, conductive ceramic powder and mixtures thereof; the metal powder is selected from one of copper, nickel, tungsten, tin, silver, gold or alloys thereof and mixtures thereof; the conductive ceramic powder is selected from one of metal nitrides, metal carbides, metal borides and metal silicides or mixtures thereof.

[0049] In one embodiment, the upper electrode 3 is formed on the upper surface of the encapsulation layer 1 .

[0050] Specifically, to address the potential heat accumulation associated with the use of a large number of conductive composite core materials 22 with positive temperature coefficients, this embodiment, in addition to adjusting the device structure to a planar device, further shifts the upper electrode 3 to the upper surface of the packaging layer 1, forming a copper electrode layer exposed on the device surface. The excellent thermal conductivity of the conductive vias 6 and the copper electrode layer facilitates heat dissipation, further addressing the heat accumulation issue.

[0051] In one embodiment, the lower electrode 4 is buried in the packaging layer 1 .

[0052] Specifically, in order to achieve a better safety effect, in this embodiment, the lower electrode 4 is buried in the packaging layer 1 to avoid short circuit.

[0053] In one embodiment, the lower electrode 4 is formed on the lower surface of the encapsulation layer 1 .

[0054] Specifically, in some high-current scenarios, the lower electrode 4 can be exposed from the lower surface of the packaging layer 1 to achieve better heat dissipation. In this embodiment, the thickness of the packaging layer 1 at the location of the lower electrode 4 should be reduced to form a saddle-shaped structure to prevent the lower electrode 4 from directly contacting the circuit board.

[0055] In one embodiment, a sealing layer 7 is provided between adjacent overcurrent protection components;

[0056] The sealing layer 7 is arranged in the vertical direction.

[0057] Specifically, in order to achieve a better insulation effect, in this embodiment, a vertically installed sealing layer 7 is inserted between adjacent overcurrent protection components to achieve insulation. The sealing layer 7 is selected from one or more combinations of epoxy resin, phenolic resin, glass fiber or inorganic filler modified epoxy resin, glass fiber or inorganic filler modified phenolic resin.

[0058] In one embodiment, a solder resist layer 8 is provided on the lower surface of the packaging layer 1 .

[0059] The solder resist layer 8 is printed with ink and is located between the two conductive pads 5 on the lower surface of the packaging layer 1. Its surface is tin-phobic, which can prevent solder from adhering to the bottom of the device during reflow soldering.

[0060] In the embodiment where the lower electrode 4 is formed on the lower surface of the packaging layer 1 , there are at least two solder resist layers 8 , each located in the gap between the conductive pad 5 and the lower electrode 4 , so that the lower electrode 4 is exposed.

[0061] In one embodiment, the number of overcurrent protection components is 2 or 4.

[0062] Specifically, the number of overcurrent protection components may be two or four or more depending on the embodiment. The following are typical embodiments:

[0063] Example 1

[0064] The cross section of the product structure of this embodiment is shown in Figure 1The overcurrent protection assembly 2 of this embodiment comprises two overcurrent protection assemblies 2, namely, two conductive composite core materials 22 with a positive temperature effect of resistance, sandwiched between upper and lower electrodes. The two layers of overcurrent protection assemblies 2 are arranged parallel to each other. The first electrode foil 21 of the left overcurrent protection assembly 2 and the first electrode foil 21 of the right overcurrent protection assembly 2 are each connected to the conductive pad 5 via a conductive via 6. The first electrode foil 21 and the conductive pad 5 are connected using the sealant of the encapsulation layer 1. The second electrode foil 23 of the left overcurrent protection assembly 2 and the second electrode foil 23 of the right overcurrent protection assembly 2 are each connected to the upper electrode 3 via a conductive via 6. The upper electrode of the overcurrent protection assembly 2 is connected to the upper copper electrode using a sealant. The gap between the two layers of overcurrent protection assemblies 2 is filled and separated by a sealing layer 7 to prevent the conductive composite core material 22 from burning due to tip discharge during power-on. The four side surfaces and the upper and lower surfaces of the conductive composite core material 22 are also coated with sealant to isolate the conductive composite core material 22 from air and moisture, thereby improving the environmental reliability of the product. The upper layer of the conductive composite core material 22 is bonded to the sealant using a copper electrode layer (top electrode 3) through a lamination or copper deposition process. This improves heat dissipation of the overcurrent protection component 2 and increases the current carrying capacity of the conductive composite core material 22. A solder mask layer 8 is added between the lower pads of the overcurrent protection component 2 to prevent the risk of short circuits during component assembly.

[0065] Example 2

[0066] The cross section of the product structure of this embodiment is shown in Figure 2The overcurrent protection element of this embodiment includes four overcurrent protection components 2, namely, four conductive composite core materials 22 with a positive temperature effect of resistance, sandwiched between upper and lower electrodes. The four layers of overcurrent protection components 2 are arranged parallel to each other. The first electrode foil 21 of the left overcurrent protection component 2 and the first electrode foil 21 of the right overcurrent protection component 2 are respectively connected to the conductive pad 5 through conductive through-holes 6. The first electrode foil 21 and the conductive pad 5 are connected using a sealing material. The first electrode foil 21 of the chips of the two middle overcurrent protection components 2 is connected to the lower electrode 4, which is located on the lower surface of the lower sealing layer 1. The second electrode foil 23 of the four overcurrent protection components 2 is respectively connected to the upper electrode 3 through conductive through-holes 6. The upper end electrode of the overcurrent protection component 2 is connected to the upper copper electrode using a sealing material. The gaps between the four overcurrent protection components 2 are filled with sealing material to isolate the overcurrent protection components 2 from burning due to sharp discharge during power-on. The four sides and upper and lower surfaces of the overcurrent protection component 2 are also covered with sealing material to isolate air and water vapor, thereby improving the environmental reliability of the product. The upper layer of the overcurrent protection component 2 is bonded to a layer of copper electrode on the sealing material by pressing or copper plating as the upper electrode 3 to improve the heat dissipation of the overcurrent protection component 2 and the current carrying capacity of the overcurrent protection component 2. An oil solder resist layer 8 is added between the conductive pads 5 of the overcurrent protection component 2 to ensure that there is no risk of short circuit when the components are mounted.

[0067] Example 3

[0068] The cross section of the product structure of this embodiment is shown in Figure 3, similar to Example 2, except that the overcurrent protection element of this embodiment includes four overcurrent protection components 2, namely, four conductive composite core materials 22 with a positive temperature effect of resistance sandwiched between upper and lower electrodes, and the four layers of overcurrent protection components 2 are distributed parallel to each other. The first electrode foil 21 of the left overcurrent protection component 2 and the first electrode foil 21 of the right overcurrent protection component 2 are respectively connected to the conductive pad 5 through conductive through-holes 6, and the first electrode foil 21 and the conductive pad 5 are connected by sealing material. The first electrode foil 21 of the chips of the two middle overcurrent protection components 2 is connected to the lower electrode 4, and the lower electrode 4 is located at the lower end of the lower sealing layer 1. The second electrode foil 23 of the four overcurrent protection components 2 is respectively connected to the upper electrode 3 through conductive through-holes 6, and the upper end electrode of the overcurrent protection component 2 is connected to the upper copper electrode by sealing material. The gaps between the four overcurrent protection components 2 are filled with sealing material to isolate the overcurrent protection components 2 from burning due to sharp discharge during power-on. The four sides and upper and lower surfaces of the overcurrent protection component 2 are also covered with sealing material to isolate air and water vapor, thereby improving the environmental reliability of the product. The upper layer of the overcurrent protection component 2 is bonded to a layer of copper electrode on the sealing material by pressing or copper plating as the upper electrode 3 to improve the heat dissipation of the overcurrent protection component 2 and the current carrying capacity of the overcurrent protection component 2. An oil solder resist layer 8 is added between the conductive pads 5 of the overcurrent protection component 2 to ensure that there is no risk of short circuit when the components are mounted.

[0069] The above are only preferred embodiments of the present invention and do not limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-reliability overcurrent protection device with improved voltage resistance, characterized in that: The high-reliability overcurrent protection device includes a packaging layer, in which at least two overcurrent protection components are arranged in a horizontal direction; Adjacent overcurrent protection components are connected in series by arranging an upper electrode above the overcurrent protection component or a lower electrode below the overcurrent protection component to form a current path.

2. The high reliability overcurrent protection device according to claim 1, characterized in that: Conductive pads are respectively provided at the bottom of the overcurrent protection component located at the first stage and the bottom of the overcurrent protection component located at the last stage.

3. The high reliability overcurrent protection device according to claim 1, characterized in that: The overcurrent protection component includes: a first electrode foil; a conductive composite material core material, wherein the conductive composite material core material is located above the first electrode foil; A second electrode foil is located above the conductive composite material core.

4. The high reliability overcurrent protection device according to claim 1, characterized in that: The upper electrode is formed on the upper surface of the packaging layer.

5. The high reliability overcurrent protection device according to claim 1, characterized in that: The lower electrode is buried in the packaging layer.

6. The high reliability overcurrent protection device according to claim 1, characterized in that: The lower electrode is formed on the lower surface of the packaging layer.

7. The high reliability overcurrent protection device according to claim 1, characterized in that: A sealing layer is provided between adjacent overcurrent protection components; The sealing layer is arranged in a vertical direction.

8. The high reliability overcurrent protection device according to claim 1, characterized in that: The lower surface of the packaging layer is provided with a solder resist layer.

9. The high reliability overcurrent protection device according to claim 1, characterized in that: The upper electrode and the lower electrode are electrically connected to the overcurrent protection component through conductive through-holes.

10. The high reliability overcurrent protection device according to claim 1, characterized in that: The number of the overcurrent protection components is 2 or 4.

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