Composite electromagnetic shielding structure for power terminal and preparation method thereof

Abstract

The invention relates to a composite electromagnetic shielding structure for a power terminal and a preparation method thereof, the structure comprises an accommodating shell, the accommodating shell is formed by connecting a plurality of composite electromagnetic shielding plates, and each composite electromagnetic shielding plate comprises an inner surface shielding layer and an outer surface shielding layer which are attached to each other; a heat conduction layer is arranged between the inner surface shielding layer and the outer surface shielding layer, and the inner surface shielding layer is located in the accommodating shell; a protective layer is arranged on the outer layer of the outer surface shielding layer and comprises an insulating layer and a waterproof layer, and the waterproof layer is located on the outer layer of the insulating layer; the outer surface shielding layer is made of a low-frequency electromagnetic field shielding material formed by mixing amorphous magnetic alloy powder, magnetic fibers and nickel powder; and the inner surface shielding layer is made of a high-frequency electromagnetic shielding material formed by mixing silicon carbide and resin foam rubber fibers. The structure can cope with various electromagnetic interference environments, provides electromagnetic shielding protection, and also has better electromagnetic shielding effectiveness for electromagnetic interference of different frequency bands.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic compatibility of power terminals, and in particular relates to a composite electromagnetic shielding structure for a power terminal and a preparation method thereof. Background Art

[0002] As an important part of smart grid construction, power terminals have been widely used. Their electromagnetic compatibility and quality reliability affect the stability and normal operation of the entire power grid. In addition, with the advancement of science and technology and the increasing sophistication of electronic products, the electromagnetic environment faced by power electronic products has become more complex, which has put forward higher requirements for the electromagnetic compatibility of products. At the same time, with the increasing attention paid to electromagnetic compatibility and the continuous deepening of related technical research, the standards and specifications for electromagnetic compatibility have become more and more stringent. Therefore, how to improve the electromagnetic compatibility of power terminals has become particularly important.

[0003] In power terminal equipment, the main task of electromagnetic shielding technology is to protect internal electronic devices from interference from external electromagnetic waves, and at the same time prevent the electromagnetic waves generated inside the equipment from leaking outward and affecting the normal operation of other equipment. Since power terminal equipment is usually installed in complex and changeable electromagnetic environments, such as substations, distribution rooms and other areas, these environments are often accompanied by high-intensity electromagnetic fields and electromagnetic pulses, which puts extremely high demands on electromagnetic shielding materials. In the current prior art, the common electromagnetic shielding structure, through metal shielding layers, grounding designs, etc., can alleviate the electromagnetic interference problem to a certain extent, but in the face of increasingly complex electromagnetic environments and the miniaturization and lightweight requirements of power terminal equipment, its limitations are becoming increasingly prominent. Therefore, the current electromagnetic shielding structure needs to further improve its electromagnetic shielding capability and range in relatively complex electromagnetic environments, and the lightweight degree and cost control of the structure are not good. Summary of the invention

[0004] The present invention provides a composite electromagnetic shielding structure for a power terminal and a preparation method thereof, aiming to solve the problems that the electromagnetic shielding capability and range of the current electromagnetic shielding structure need to be further improved in a relatively complex electromagnetic environment, and the lightweight degree and cost control of the structure are poor.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A composite electromagnetic shielding structure for a power terminal, comprising a housing, the housing being capable of accommodating a power terminal part so as to achieve electromagnetic shielding of the power terminal part, wherein:

[0007] The housing is formed by connecting a plurality of composite electromagnetic shielding plates, each of which includes an inner surface shielding layer and an outer surface shielding layer that are bonded to each other, a heat conducting layer is arranged between the inner surface shielding layer and the outer surface shielding layer, and the inner surface shielding layer is located inside the housing;

[0008] The outer layer of the outer surface shielding layer is provided with a protective layer, the protective layer includes an insulating layer and a waterproof layer, and the waterproof layer is located on the outer layer of the insulating layer;

[0009] The material of the outer surface shielding layer includes a low-frequency electromagnetic field shielding material mixed with amorphous magnetic alloy powder, magnetic fiber and nickel powder; the material of the inner surface shielding layer includes a high-frequency electromagnetic shielding material mixed with silicon carbide and resin foam fiber.

[0010] In some embodiments, the low-frequency electromagnetic field shielding material includes, by mass percentage, 50% to 60% amorphous magnetic alloy powder, 15% to 25% magnetic fiber, and 20% to 30% nickel powder.

[0011] Furthermore, the thickness of the outer surface shielding layer is controlled to be 0.2 mm to 1 mm.

[0012] In some embodiments, the high-frequency electromagnetic field shielding material includes, by mass percentage: 60% to 80% silicon carbide and 20% to 40% resin foam fibers.

[0013] Furthermore, the thickness of the inner surface shielding layer is controlled to be 0.1 mm to 0.5 mm.

[0014] In some embodiments, the heat-conducting layer is made of a heat-conducting rubber material, and the thickness of the heat-conducting layer is controlled to be 0.5 mm to 2 mm.

[0015] In some embodiments, the insulating layer is made of polyimide material, and the thickness of the insulating layer is controlled to be 0.5 mm to 2 mm.

[0016] In some embodiments, the waterproof layer is a polyvinyl chloride waterproof membrane, and the thickness of the waterproof layer is controlled to be 0.1 mm to 0.5 mm.

[0017] In some embodiments, at least two of the plurality of composite electromagnetic shielding panels are connected in a detachable manner.

[0018] The present invention also discloses a method for preparing a composite electromagnetic shielding structure for a power terminal, comprising the following steps:

[0019] Select materials and cut them according to the structure of the power terminal to obtain a heat-conducting layer;

[0020] The low-frequency electromagnetic field shielding material and the high-frequency electromagnetic field shielding material are respectively coated on both sides of the heat conductive layer, the low-frequency electromagnetic field shielding material forms an outer surface shielding layer, and the high-frequency electromagnetic field shielding material forms an inner surface shielding layer;

[0021] An insulating layer is coated on the side of the outer surface shielding layer away from the heat conductive layer; a waterproof layer is attached to the side of the insulating layer away from the outer surface shielding layer to form a plate-like structure;

[0022] According to the structure of the power terminal part, the plate-like structure is cut into a plurality of composite electromagnetic shielding plates, and the plurality of composite electromagnetic shielding plates are assembled and installed on the power terminal part to form a composite electromagnetic shielding structure.

[0023] Compared with the prior art, the composite electromagnetic shielding structure for a power terminal and the preparation method thereof of the present invention have the following beneficial effects:

[0024] The present invention discloses a composite electromagnetic shielding structure for a power terminal, comprising a housing, the housing can accommodate a power terminal part, so as to realize electromagnetic shielding of the power terminal part, wherein: the housing is formed by connecting a plurality of composite electromagnetic shielding plates, each composite electromagnetic shielding plate comprises an inner surface shielding layer and an outer surface shielding layer which are bonded to each other, a heat conducting layer is arranged between the inner surface shielding layer and the outer surface shielding layer, and the inner surface shielding layer is located inside the housing; the outer layer of the outer surface shielding layer is provided with a protective layer, the protective layer comprises an insulating layer and a waterproof layer, and the waterproof layer is located outside the insulating layer; the material of the outer surface shielding layer comprises a low-frequency electromagnetic field shielding material mixed with amorphous magnetic alloy powder, magnetic fiber and nickel powder; the material of the inner surface shielding layer comprises a high-frequency electromagnetic shielding material mixed with silicon carbide and resin foam rubber fiber. Based on the above, the present invention forms a composite electromagnetic shielding structure by laying the inner surface shielding material and the outer surface shielding material on the inner and outer surfaces of the heat conducting layer respectively, the insulating layer completely covers the surface of the outer surface shielding material, the waterproof film is tightly attached to the outer surface of the insulating layer, and finally cutting and combining to form the composite electromagnetic shielding structure. The structure of the present invention can effectively shield electromagnetic waves of different frequency bands by designing an inner surface shielding layer and an outer surface shielding layer made of different materials. The inner surface shielding layer adopts a high-frequency electromagnetic shielding material mixed with silicon carbide and resin foam rubber fiber, which has a good shielding effect on high-frequency electromagnetic waves; while the outer surface shielding layer adopts a low-frequency electromagnetic field shielding material mixed with amorphous magnetic alloy powder, magnetic fiber and nickel powder, which effectively shields low-frequency electromagnetic waves. This enables the structure to cope with a variety of electromagnetic interference environments and provide comprehensive electromagnetic shielding protection. The present invention adopts multi-layer shielding materials, which can make the structure have better electromagnetic shielding efficiency when facing electromagnetic interference of different frequency bands; the present invention utilizes the high magnetic permeability material on the outer surface to improve the low-frequency electromagnetic field shielding ability of the structure, utilizes thermal conductive rubber to improve the heat dissipation ability of the structure, and utilizes the high-frequency absorbing material on the inner surface to improve the high-frequency electromagnetic field shielding ability of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 A cross-sectional schematic diagram of a layered structure of a composite electromagnetic shielding structure for a power terminal and a preparation method thereof according to the present invention;

[0027] Figure 2 The present invention is a schematic diagram of the installation and application state of a composite electromagnetic shielding structure for a power terminal and a preparation method thereof.

[0028] Among them, 1. inner surface shielding layer, 2. outer surface shielding layer, 3. thermal conductive layer, 4. insulating layer, 5. waterproof layer. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0032] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0033] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] How to provide a structure with high-frequency electromagnetic field shielding capability and a wide electromagnetic shielding range, and form the material of the electromagnetic shielding structure through material selection and proportioning, thereby improving the electromagnetic shielding capability of the power terminal and protecting the reliability of the power terminal.

[0036] like Figure 1 As shown, the present invention provides a composite electromagnetic shielding structure for a power terminal, comprising a housing, the housing being capable of accommodating a power terminal portion so as to achieve electromagnetic shielding of the power terminal portion, wherein:

[0037] The housing is formed by connecting a plurality of composite electromagnetic shielding plates, each of which includes an inner surface shielding layer 1 and an outer surface shielding layer 2 which are attached to each other, a heat conducting layer 3 is arranged between the inner surface shielding layer 1 and the outer surface shielding layer 2, and the inner surface shielding layer 1 is located inside the housing;

[0038] The outer layer of the outer surface shielding layer 2 is provided with a protective layer, the protective layer includes an insulating layer 4 and a waterproof layer 5, and the waterproof layer 5 is located on the outer layer of the insulating layer 4;

[0039] The material of the outer surface shielding layer 2 includes a low-frequency electromagnetic field shielding material mixed with amorphous magnetic alloy powder, magnetic fiber and nickel powder; the material of the inner surface shielding layer 1 includes a high-frequency electromagnetic shielding material mixed with silicon carbide and resin foam fiber.

[0040] The present invention discloses a composite electromagnetic shielding structure for a power terminal. For electromagnetic interference in different frequency bands, the composite electromagnetic shielding structure adopts a multi-layer shielding material to improve the electromagnetic shielding efficiency of the composite electromagnetic shielding structure; the high magnetic permeability material on the outer surface is used to improve the low-frequency electromagnetic field shielding capability of the composite electromagnetic shielding structure; the heat-conducting rubber is used to improve the heat dissipation capability of the composite electromagnetic shielding structure; the high-frequency wave-absorbing material on the inner surface is used to improve the high-frequency electromagnetic field shielding capability of the composite electromagnetic shielding structure. Overall, the composite electromagnetic shielding structure has the advantages of easy installation, wide electromagnetic shielding range and strong electromagnetic shielding capability, and has good practical significance.

[0041] Specifically, the present invention sets a heat conductive layer 3 between the inner surface shielding layer 1 and the outer surface shielding layer 2, which can effectively dissipate the heat generated by the power terminal, improve the heat dissipation performance of the entire power terminal, and avoid power terminal failure or performance degradation due to overheating.

[0042] Furthermore, the present invention further provides a protective layer including an insulating layer 4 and a waterproof layer 5 on the outer layer of the outer surface shielding layer 2, further enhancing the protection capability of the structure. During actual installation and application, the insulating layer 4 can prevent current leakage and improve safety; while the waterproof layer 5 can prevent moisture from intruding and protect the electronic components inside the power terminal from damage.

[0043] In a composite electromagnetic shielding structure for a power terminal of the present invention, a waterproof layer 5 is used to form a waterproof membrane, and the waterproof membrane is a polyvinyl chloride (PVC) waterproof membrane. The material has good waterproof performance and weather resistance, and is generally controlled at 0.1mm to 0.5mm to ensure sufficient waterproof effect while not affecting the lightness of the overall structure. In actual working conditions, the waterproof membrane is tightly attached to the outer surface of the insulating layer 4 by an adhesive (such as hot melt adhesive, double-sided adhesive, etc.) to ensure seamless connection.

[0044] In the composite electromagnetic shielding structure for power terminals of the present invention, the insulating layer 4 is made of polyimide material, which has good electrical insulation performance and high temperature resistance. The thickness of the insulating layer 4 is generally controlled to be 0.5 mm to 2 mm to ensure sufficient electrical insulation effect while maintaining the lightness of the structure. The insulating layer 4 is tightly attached to the surface of the outer surface shielding material through coating, injection molding and other processes to ensure that there are no bubbles or gaps.

[0045] In a composite electromagnetic shielding structure for a power terminal of the present invention, in order to improve the low-frequency electromagnetic field shielding effectiveness of the power terminal, the outer surface shielding material is selected from a high magnetic permeability coating composed of amorphous magnetic alloy powder, magnetic fiber and nickel powder. Amorphous magnetic alloy powder is the main magnetic permeability component of the coating, so the amorphous magnetic alloy powder should account for a large proportion of the total weight of the coating, and the mass percentage range of the amorphous magnetic alloy powder can be selected to be 50% to 60%, depending on the required magnetic permeability and shielding effectiveness. The magnetic fiber can enhance the magnetic permeability and mechanical strength of the coating. The mass percentage range of the magnetic fiber can be selected to be 15% to 25% to provide sufficient magnetic permeability and structural stability. The nickel powder material has good electrical conductivity and magnetic permeability, which can further improve the shielding effectiveness of the coating. The mass percentage range of the nickel powder is selected to be 20% to 30%, depending on the required electrical conductivity and cost considerations. When processing the structure, the high magnetic permeability coating is evenly brushed on the outer surface of the thermal conductive layer 3. The thickness of the outer surface shielding layer 2 is controlled to be 0.2mm to 1mm to ensure sufficient shielding effect while controlling cost.

[0046] In order to ensure the heat dissipation performance of the power terminal, the heat conductive layer 3 in the composite electromagnetic shielding structure for the power terminal of the present invention adopts a heat conductive rubber material, which has good thermal conductivity and high-level pressure resistance, and is used to improve the heat dissipation capacity of the composite electromagnetic shielding structure. The thickness of the heat conductive layer 3 is controlled to be 0.5mm to 2mm to ensure sufficient heat conduction effect while maintaining the stability of the structure. The heat conductive layer 3 is tightly attached between the outer surface shielding material and the inner surface shielding material by an adhesive to ensure that heat can be transferred smoothly.

[0047] In order to improve the high-frequency electromagnetic field shielding effectiveness of the power terminal, in a composite electromagnetic shielding structure for a power terminal of the present invention, the inner surface shielding material adopts a high-frequency electromagnetic shielding material composed of silicon carbide and resin foam glue fiber. In specific working conditions, the high-frequency electromagnetic material is pasted on the inner surface of the heat-conducting layer 3 by glue. Silicon carbide is the main component of the high-frequency electromagnetic shielding material, and the mass percentage of silicon carbide is selected and controlled to be 60% to 80%. Because it has high hardness, high strength, high wear resistance and excellent electromagnetic properties, it has a better advantage when used as the shielding material of the present invention to ensure sufficient shielding effectiveness and mechanical strength. The present invention selects 20% to 40% of resin foam glue fiber as a binder and a reinforcing agent, which can improve the overall performance and processability of the material to provide a good bonding effect and a certain flexibility. In actual working conditions, the inner surface shielding material can be sprayed on the other side of the heat-conducting layer 3 by spraying, but not limited to. The thickness of the inner surface shielding layer 1 is controlled to be 0.1mm to 0.5mm to ensure sufficient shielding effect while maintaining the thinness of the structure. During the preparation process, it should be ensured that silicon carbide and resin foam fibers are mixed evenly to avoid agglomeration or stratification.

[0048] The present invention limits the specific ratio and range of low-frequency electromagnetic field shielding materials, outer surface shielding layer thickness, high-frequency electromagnetic field shielding materials, and inner surface shielding layer thickness according to the above parameters, which helps to more accurately control the shielding effect and production cost, and improve the cost performance of the product. In addition, the present invention selects and controls the material selection and thickness of the thermal conductive layer, the insulating layer, and the waterproof layer, further improving the heat dissipation performance, safety performance, and waterproof performance of the composite electromagnetic shielding structure, ensuring that the power terminal can operate stably in relatively harsh and complex environments.

[0049] The present invention also provides a method for preparing a composite electromagnetic shielding structure for a power terminal, comprising the following steps:

[0050] Select materials according to the structure of the power terminal part and cut them to obtain the heat conducting layer 3;

[0051] The low-frequency electromagnetic field shielding material and the high-frequency electromagnetic field shielding material are respectively coated on both sides of the heat conductive layer 3, the low-frequency electromagnetic field shielding material forms the outer surface shielding layer 2, and the high-frequency electromagnetic field shielding material forms the inner surface shielding layer 1;

[0052] An insulating layer 4 is coated on the side of the outer surface shielding layer 2 away from the heat conducting layer 3; a waterproof layer 5 is attached to the side of the insulating layer 4 away from the outer surface shielding layer 2 to form a plate-like structure;

[0053] like Figure 2 As shown, according to the structure of the power terminal part, the plate-like structure is cut into a plurality of composite electromagnetic shielding plates, and the plurality of composite electromagnetic shielding plates are combined and installed on the power terminal part to form a composite electromagnetic shielding structure.

[0054] Specifically, the present invention further describes in detail a composite electromagnetic shielding structure for a power terminal and a preparation method thereof through the following embodiments.

[0055] A thermally conductive rubber material with a thickness of 1.5 mm is selected as the thermally conductive layer 3 to provide a solid base for subsequent high-frequency electromagnetic shielding materials, low-frequency high magnetic conductivity coatings and insulation layers. The excellent thermal conductivity of the thermally conductive layer 3 ensures that the heat generated inside the power terminal can be quickly and evenly transferred to the external heat dissipation system, thereby maintaining the normal operating temperature of the power terminal equipment.

[0056] Prepare a high-frequency electromagnetic shielding material, which is evenly mixed with 75% by mass of silicon carbide and 25% by mass of resin foam fiber, and use a scraping or spraying process to evenly cover it on the inner surface of the preset thermal conductive layer 3 to form a thin and efficient shielding layer to provide high-frequency electromagnetic field shielding for the power terminal.

[0057] Prepare high magnetic permeability coating, mix 50% amorphous magnetic alloy powder, 20% magnetic fiber and 30% nickel powder in a uniform ratio, use spraying equipment to evenly spray the coating on the outer surface of the thermal conductive layer 3 to form a 0.4 mm thick coating to enhance the shielding effectiveness of the power terminal against low-frequency electromagnetic fields.

[0058] A polyimide material with a thickness of 0.8 mm is selected as the insulating layer 4 and is cut according to the specific shape and size of the power terminal to ensure that it can completely cover the outer surface shielding material (i.e. the thermal conductive layer 3 coated with a high magnetic conductivity coating) and fit tightly through injection molding to provide electrical isolation and high-temperature protection.

[0059] A polyvinyl chloride (PVC) waterproof membrane with a thickness of 0.2 mm is selected. After cleaning to remove impurities, it is cut to a suitable size according to the size of the power terminal and tightly adhered to the outer surface of the insulating layer 4 using hot melt adhesive to ensure seamless connection and form an effective waterproof barrier.

[0060] Finally, in actual working conditions, according to the structural characteristics of the power terminal casing, the multi-layer electromagnetic shielding structure is designed with a detachable shielding component, which is installed on the power terminal casing by bolts, clips or other fixing methods to protect the power terminal from the influence of the humid environment, thus completing the preparation of the entire composite electromagnetic shielding structure from the inside to the outside.

[0061] The present invention provides a composite electromagnetic shielding structure for a power terminal and a preparation method thereof. The composite electromagnetic shielding structure has a simple structure and a reasonable design. It adopts a combination of high-frequency electromagnetic shielding materials and low-frequency electromagnetic shielding materials. In practical applications, it effectively blocks electromagnetic interference of different frequencies to the power terminal, ensuring the stable operation of the power terminal. At the same time, the present invention not only improves the heat dissipation efficiency, but also enhances the moisture-proof performance and prolongs the service life through the application of a thermal conductive layer and a waterproof film. The present invention is easy to install, and has certain advantages in electromagnetic shielding range and electromagnetic shielding capability.

[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the specification and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A composite electromagnetic shielding structure for a power terminal, characterized in that: The invention comprises a housing, wherein the housing can accommodate the power terminal part so as to achieve electromagnetic shielding of the power terminal part, wherein: The housing is formed by connecting a plurality of composite electromagnetic shielding plates, each of the composite electromagnetic shielding plates comprising an inner surface shielding layer (1) and an outer surface shielding layer (2) which are bonded to each other, a heat conducting layer (3) is provided between the inner surface shielding layer (1) and the outer surface shielding layer (2), and the inner surface shielding layer (1) is located inside the housing; The outer layer of the outer surface shielding layer (2) is provided with a protective layer, the protective layer comprises an insulating layer (4) and a waterproof layer (5), and the waterproof layer (5) is located on the outer layer of the insulating layer (4); The material of the outer surface shielding layer (2) comprises a low-frequency electromagnetic field shielding material formed by a mixture of amorphous magnetic alloy powder, magnetic fiber and nickel powder; the material of the inner surface shielding layer (1) comprises a high-frequency electromagnetic shielding material formed by a mixture of silicon carbide and resin foam fiber.

2. The composite electromagnetic shielding structure for a power terminal according to claim 1, characterized in that: Measured in mass percentage, the low-frequency electromagnetic field shielding material comprises: 50% to 60% of amorphous magnetic alloy powder, 15% to 25% of magnetic fiber and 20% to 30% of nickel powder.

3. The composite electromagnetic shielding structure for a power terminal according to claim 2, characterized in that: The thickness of the outer surface shielding layer (2) is controlled to be 0.2 mm to 1 mm.

4. The composite electromagnetic shielding structure for a power terminal according to claim 1, characterized in that: Measured in mass percentage, the high-frequency electromagnetic field shielding material comprises: 60% to 80% silicon carbide and 20% to 40% resin foam rubber fibers.

5. The composite electromagnetic shielding structure for a power terminal according to claim 4, characterized in that: The thickness of the inner surface shielding layer (1) is controlled to be 0.1 mm to 0.5 mm.

6. The composite electromagnetic shielding structure for a power terminal according to claim 1, characterized in that: The heat-conducting layer (3) is made of a heat-conducting rubber material, and the thickness of the heat-conducting layer (3) is controlled to be 0.5 mm to 2 mm.

7. The composite electromagnetic shielding structure for a power terminal according to claim 1, characterized in that: The insulating layer (4) is made of polyimide material, and the thickness of the insulating layer (4) is controlled to be 0.5 mm to 2 mm.

8. The composite electromagnetic shielding structure for a power terminal according to claim 1, characterized in that: The waterproof layer (5) is made of a polyvinyl chloride waterproof membrane, and the thickness of the waterproof layer (5) is controlled to be 0.1 mm to 0.5 mm.

9. The composite electromagnetic shielding structure for a power terminal according to claim 1, characterized in that: At least two of the plurality of composite electromagnetic shielding panels are connected in a detachable manner.

10. A method for preparing a composite electromagnetic shielding structure for a power terminal according to any one of claims 1 to 9, characterized in that: The steps include: Selecting materials according to the structure of the power terminal part and cutting them to obtain a heat conducting layer (3); A low-frequency electromagnetic field shielding material and a high-frequency electromagnetic field shielding material are respectively coated on both sides of the heat conductive layer (3), the low-frequency electromagnetic field shielding material forms an outer surface shielding layer (2), and the high-frequency electromagnetic field shielding material forms an inner surface shielding layer (1); An insulating layer (4) is coated on the side of the outer surface shielding layer (2) away from the heat conducting layer (3); and a waterproof layer (5) is attached to the side of the insulating layer (4) away from the outer surface shielding layer (2) to form a plate-like structure; According to the structure of the power terminal part, the plate-like structure is cut into a plurality of composite electromagnetic shielding plates, and the plurality of composite electromagnetic shielding plates are assembled and installed on the power terminal part to form a composite electromagnetic shielding structure.

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