High-temperature-resistant PPTC fuse for outdoor industrial control equipment

Abstract

The utility model provides a high-temperature-resistant PPTC fuse for outdoor industrial control equipment. The high-temperature-resistant PPTC fuse comprises a substrate layer, a positive temperature coefficient composite material layer and a pair of front bonding pads, the substrate layer is made of a high polymer material; the positive temperature coefficient composite material layer is formed on the substrate layer; the front bonding pad is arranged on the upper surface of the positive temperature coefficient composite material layer and forms a left bonding pad and a right bonding pad which are separated from each other; the substrate layer and the positive temperature coefficient composite material layer are mutually laminated through a copper foil layer; the positive temperature coefficient composite material layer is composed of polyvinylidene fluoride and conductive particles distributed in the polyvinylidene fluoride; polyvinylidene fluoride (PVDF) is used as a main material of the positive temperature coefficient composite material layer, and the PVDF has relatively high thermal stability and ageing resistance, so that the PPTC fuse still keeps stable performance in a high-temperature environment, and is suitable for outdoor and high-temperature conditions.

Description

Technical Field

[0001] This utility model relates to the field of fuse technology, and more specifically, to a high-temperature resistant PPTC fuse for outdoor industrial control equipment. Background Technology

[0002] The core of a PPTC fuse is made of polymer materials and conductive particles, with nickel electrodes at both ends, and an outer coating of resin or plastic film. At low temperatures, the conductive particles between the polymer crystals form a three-dimensional network, exhibiting conductivity. When the current is too high, causing the temperature to rise, the volume expands, and the polymer changes from a crystalline state to an amorphous state, breaking the network of conductive particles and thus preventing conductivity or providing insulation. When the temperature drops and the high current ceases, the fuse recovers its crystalline state after a short period, regaining conductivity.

[0003] Therefore, under normal temperature and current, the conductive particles form continuous conductive paths within the polymer matrix, allowing PPTC to maintain a low resistance. When the current is too high, causing the temperature to rise, the polymer matrix changes from a crystalline state to an amorphous state due to thermal expansion. The connections between the conductive particles are disrupted, leading to a sharp increase in resistance, which in turn restricts current flow and achieves overcurrent protection.

[0004] However, current PPTC fuses, on the one hand, use a polymer matrix as the base material directly for both power interruption and conduction, resulting in a large amount of composite material and a lack of a stable supporting base. On the other hand, conventional polymer matrices alone cannot meet increasingly stringent temperature requirements, making them unsuitable for outdoor and high-temperature conditions. Therefore, this application is hereby submitted. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a high-temperature resistant PPTC fuse for outdoor industrial control equipment to solve the above problems.

[0006] The present invention adopts the following solution:

[0007] This application provides a high-temperature resistant PPTC fuse for outdoor industrial control equipment, comprising: a base layer, a positive temperature coefficient composite material layer, and a pair of front pads; the base layer is composed of a polymer material; the positive temperature coefficient composite material layer is formed on the base layer; the front pads are disposed on the upper surface of the positive temperature coefficient composite material layer and form a left pad and a right pad separated from each other; the base layer and the positive temperature coefficient composite material layer are stacked together through a copper foil layer; the positive temperature coefficient composite material layer is composed of polyvinylidene fluoride and conductive particles distributed therein.

[0008] As a further improvement, the left pad is electrically connected to the positive temperature coefficient composite material layer through a left electrode, and the right pad is electrically connected to the positive temperature coefficient composite material layer through a right electrode.

[0009] As a further improvement, the conductive particles include at least carbon black and calcium carbonate; each conductive particle is configured to be uniformly mixed into polyvinylidene fluoride after being dispersed.

[0010] As a further improvement, the total content of carbon black and calcium carbonate accounts for 20% to 25% of polyvinylidene fluoride, and the content of carbon black is greater than the content of calcium carbonate.

[0011] As a further improvement, the thickness of the positive temperature coefficient composite material layer is more than twice the thickness of the copper foil layer, and the positive temperature coefficient composite material layer and the copper foil layer cooperate to be configured to limit the applicable temperature of the entire high-temperature resistant PPTC fuse to the range of -40°C to 125°C.

[0012] As a further improvement, the thickness of the substrate layer is at least 3 / 4 of the total thickness.

[0013] As a further improvement, the left and right pads are formed on the outer periphery of the surface of the PPTC fuse, and the two pads are tightly bonded to the positive temperature coefficient composite material layer.

[0014] As a further improvement, the high-temperature PPTC fuse also includes a pair of back pads and another positive temperature coefficient composite material layer formed beneath the substrate.

[0015] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0016] 1. The high-temperature resistant PPTC fuse for outdoor industrial control equipment of this application uses polyvinylidene fluoride (PVDF) as the main material of the positive temperature coefficient composite material layer. PVDF has high thermal stability and anti-aging properties, which enables the PPTC fuse to maintain stable performance in high-temperature environments and is suitable for outdoor and high-temperature conditions.

[0017] 2. Adding a copper foil layer between the base layer and the positive temperature coefficient composite material layer helps to increase thermal conductivity, thereby quickly conducting heat and triggering a protective effect when the temperature rises sharply. Furthermore, the configuration of the copper foil layer also increases the overall mechanical strength of the structure, which helps to improve durability.

[0018] 3. In particular, the base layer is made of polymer materials, which provides the necessary support and durability for the entire device. The selection of polymer materials for the base layer can be optimized according to actual environmental requirements to enhance its moisture resistance, UV resistance and other properties, further improving its outdoor applicability. In addition, the conductive particles distributed in the positive temperature coefficient composite material layer form conductive paths at low temperatures. When the temperature rises and the matrix expands, the connection of the conductive particles is broken, the resistance increases, and the current is effectively limited. This not only enables automatic recovery but also greatly reduces the equipment maintenance cost and the difficulty of use. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a high-temperature resistant PPTC fuse for outdoor industrial control equipment according to an embodiment of this utility model;

[0020] Figure 2 This is an exploded schematic diagram of a high-temperature resistant PPTC fuse for outdoor industrial control equipment according to an embodiment of this utility model;

[0021] Figure 3 This is a cross-sectional view of a high-temperature resistant PPTC fuse for outdoor industrial control equipment according to an embodiment of this utility model;

[0022] Figure 4 This is a schematic diagram of the structure of a high-temperature resistant PPTC fuse for outdoor industrial control equipment according to a preferred embodiment of the present invention.

[0023] Icons: 1-Base layer; 2-Positive temperature coefficient composite layer; 3-Left pad; 4-Right pad; 5-Copper foil layer; 6-Left electrode sheet; 7-Right electrode sheet; 8-Back pad. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0025] Example

[0026] Combination Figures 1 to 3This embodiment provides a high-temperature resistant PPTC fuse for outdoor industrial control equipment, comprising: a base layer 1, a positive temperature coefficient composite material layer 2, and a pair of front pads.

[0027] The substrate layer 1 is composed of a polymer material. The positive temperature coefficient composite material layer 2 is formed on the substrate layer 1. The front pads are disposed on the upper surface of the positive temperature coefficient composite material layer 2 and form a left pad 3 and a right pad 4 that are separated from each other.

[0028] The base layer 1 and the positive temperature coefficient composite material layer 2 are stacked together by a copper foil layer 5. The positive temperature coefficient composite material layer 2 is composed of polyvinylidene fluoride and conductive particles distributed within it.

[0029] The high-temperature resistant PPTC fuse mentioned above uses polyvinylidene fluoride (PVDF) as the main material of the positive temperature coefficient composite layer 2. PVDF has high thermal stability and anti-aging properties, which enables the PPTC fuse to maintain stable performance in high-temperature environments and is suitable for outdoor and high-temperature conditions.

[0030] Adding a copper foil layer 5 between the base layer 1 and the positive temperature coefficient composite material layer 2 helps to increase thermal conductivity, thereby rapidly conducting heat and triggering a protective effect when the temperature rises sharply. Furthermore, the configuration of the copper foil layer 5 also increases the overall mechanical strength of the structure, which helps to improve durability.

[0031] The base layer 1 is made of polymer material, which provides necessary support and durability for the entire device. The selection of polymer material for the base layer 1 can be optimized according to actual environmental requirements to enhance its moisture resistance, UV resistance and other properties, and further improve its outdoor applicability. In addition, the conductive particles distributed in the positive temperature coefficient composite material layer 2 form a conductive path at low temperature. When the temperature rises and the matrix expands, the connection of the conductive particles is broken and the resistance increases, thereby effectively limiting the current. This not only enables automatic recovery but also greatly reduces the equipment maintenance cost and the difficulty of use.

[0032] like Figure 3 As shown, in this embodiment, the left pad 3 is electrically connected to the positive temperature coefficient composite material layer 2 via a left electrode 6, and the right pad 4 is electrically connected to the positive temperature coefficient composite material layer 2 via a right electrode 7. Specifically, the left pad 3 and the right pad 4 are electrically connected to the positive temperature coefficient composite material layer 2 via the left electrode 6 and the right electrode 7, respectively, so that the current flows stably through the composite material layer through the electrode plates. In particular, the electrode plates make the current evenly distributed on the composite material layer, reducing the risk of local current concentration, thereby avoiding local overheating and improving the conductivity and reliability of the entire PPTC fuse.

[0033] In this embodiment, the conductive particles include at least carbon black and calcium carbonate. Each conductive particle is configured to be uniformly mixed into the polyvinylidene fluoride (PVDF) after being dispersed. Carbon black has good conductivity; using it as the main conductive particle significantly improves the overall conductivity of the composite layer, allowing the PPTC fuse to maintain a low resistance under normal operating current. Calcium carbonate, as a filler, enhances the thermal stability and anti-aging properties of the PVDF matrix. At high temperatures, calcium carbonate provides stable physical support, preventing performance degradation after repeated expansion and contraction, and extending the service life of the PPTC fuse.

[0034] It's worth mentioning that after being dispersed, the conductive particles are evenly distributed within the PVDF matrix, forming a stable conductive network. When excessive current causes the material to expand, the network connections of the conductive particles break, preventing current flow. As the temperature decreases, the conductive network quickly recovers, achieving a self-healing function. The uniformly dispersed conductive particles ensure the stability of the conductive network, making overcurrent protection more reliable.

[0035] Preferably, the total content of carbon black and calcium carbonate accounts for 20% to 25% of polyvinylidene fluoride, and the content of carbon black is greater than the content of calcium carbonate. Controlling the total content of carbon black and calcium carbonate within the range of 20% to 25% maintains the material's good electrical conductivity while avoiding the adverse effects of excessively high filler ratios on the matrix's flexibility and thermal expansion properties. The addition of less calcium carbonate than carbon black helps improve the material's mechanical strength without excessively increasing its hardness, thus maintaining a certain degree of flexibility.

[0036] In this embodiment, the thickness of the positive temperature coefficient composite material layer 2 is more than twice the thickness of the copper foil layer 5. The positive temperature coefficient composite material layer 2 and the copper foil layer 5 cooperate to limit the applicable temperature of the entire high-temperature PPTC fuse to the range of -40°C to 125°C. The thicker PTC composite material layer provides better thermal expansion control, enabling a rapid increase in resistance when the temperature reaches a critical point for overcurrent protection. The thinner copper foil layer 5 works in conjunction with this, rapidly transferring heat to a wider area of ​​the composite material through heat conduction, accelerating the response speed and ensuring stability in both high and low temperature environments. Furthermore, by strictly controlling the thickness ratio of the composite material layer and the copper foil layer 5, the PPTC fuse can maintain its electrical performance and physical integrity over a wide temperature range (-40°C to 125°C).

[0037] Furthermore, the thickness of the base layer 1 is at least three-quarters of the total thickness. Thus, the base layer 1 constitutes the majority of the thickness, providing robust support for the entire fuse structure. Especially in harsh applications such as outdoor and industrial control systems, PPTC fuses frequently face environmental stresses such as temperature fluctuations, mechanical vibrations, and shocks. A thicker base layer 1 can effectively resist these stresses, preventing material deformation or performance degradation.

[0038] Clearly, the thicker base layer 1 can insulate against external high temperatures, protecting the internal PTC composite material layer and copper foil layer 5 from direct exposure to extreme temperatures, thereby extending the fuse's lifespan. Simultaneously, the thick base layer 1 provides a buffer against heat, preventing drastic temperature changes from affecting the fuse's performance. Furthermore, due to the greater thickness of the base layer 1, it provides excellent electrical isolation, preventing the risk of accidental leakage or short circuits.

[0039] In this embodiment, the left pad 3 and right pad 4 are formed on the outer periphery of the PPTC fuse surface, and the two pads are tightly bonded to the positive temperature coefficient composite material layer 2. This allows current to be conducted more directly and stably to the composite material layer, reducing electrical connection instability and the possibility of contact resistance. The symmetrical distribution of the left pad 3 and right pad 4 on the outer periphery makes the current flow more uniform throughout the entire composite material layer, effectively avoiding localized overheating. This provides more reliable electrical performance in outdoor and industrial control equipment, reducing contact problems caused by environmental factors such as vibration and impact.

[0040] like Figure 4 As shown, in a preferred embodiment, the high-temperature resistant PPTC fuse further includes a pair of back pads 8 and another positive temperature coefficient composite material layer 2 formed below the substrate layer 1. Obviously, the back pads 8 and their composite material layer can specifically refer to the connection configuration of the front pads and their composite material layer described above. The configuration of the upper and lower double-layer composite material can more evenly distribute heat, avoiding localized overheating that may occur in a single-layer structure. Preferably, the arrangement of the front and back pads allows for more flexible electrical connection methods to adapt to different installation requirements.

[0041] The above are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions that fall within the scope of this utility model's concept are protected by this utility model.

Claims

1. A high-temperature resistant PPTC fuse for outdoor industrial control equipment, characterized in that, include: The base layer is composed of polymer materials; A positive temperature coefficient composite material layer is formed on the substrate layer; A pair of front pads are configured on the upper surface of the positive temperature coefficient composite layer and form a left pad and a right pad that are separated from each other; The base layer and the positive temperature coefficient composite material layer are stacked together by a copper foil layer; Furthermore, the positive temperature coefficient composite material layer is composed of polyvinylidene fluoride and conductive particles distributed within it.

2. The high-temperature resistant PPTC fuse for outdoor industrial control equipment according to claim 1, characterized in that, The left pad is electrically connected to the positive temperature coefficient composite material layer through a left electrode, and the right pad is electrically connected to the positive temperature coefficient composite material layer through a right electrode.

3. The high-temperature resistant PPTC fuse for outdoor industrial control equipment according to claim 1, characterized in that, The thickness of the positive temperature coefficient composite material layer is more than twice the thickness of the copper foil layer, and the positive temperature coefficient composite material layer and the copper foil layer cooperate to be configured to limit the applicable temperature of the entire high temperature resistant PPTC fuse to the range of -40°C to 125°C.

4. The high-temperature resistant PPTC fuse for outdoor industrial control equipment according to claim 1, characterized in that, The thickness of the base layer is at least 3 / 4 of the total thickness.

5. The high-temperature resistant PPTC fuse for outdoor industrial control equipment according to claim 1, characterized in that, The left and right pads are formed on the outer periphery of the surface of the PPTC fuse, and the two pads are tightly bonded to the positive temperature coefficient composite material layer.

6. The high-temperature resistant PPTC fuse for outdoor industrial control equipment according to claim 1, characterized in that, It also includes a pair of back pads and another positive temperature coefficient composite layer formed beneath the substrate.

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