Insulated electric wire, method for manufacturing the same, coil, and electronic / electrical device

Abstract

The application belongs to the technical field of electric wire and cable, and discloses an insulating electric wire and a preparation method thereof, a coil and an electronic / electrical device, wherein the insulating electric wire comprises a conductor and an adhesive layer and an insulating layer arranged outside the conductor in sequence, the insulating layer comprises polyether ether ketone resin and a corona-resistant filler, and the corona-resistant filler is composed of corona-resistant inorganic particles and a compatible resin wrapped on part or all of the outer surface of the corona-resistant inorganic particles. In the insulating layer of PEEK, the corona-resistant inorganic particles with the compatible resin grafted on the surface are introduced, the dispersion of the corona-resistant inorganic particles and the interfacial bonding force between the corona-resistant inorganic particles and the matrix are improved by using the good compatibility of the compatible resin with the PEEK matrix. The compatible resin enables the PEEK and the corona-resistant inorganic particles to be uniformly mixed, thereby ensuring the adhesion between each other, which helps to reduce the partial discharge phenomenon caused by the interface defects and enhances the resistance of the corona-resistant filler to the corona erosion.

Description

Technical Field

[0001] This application belongs to the technical field of wires and cables, and particularly relates to an insulated wire and its preparation method, coils, and electronic / electrical devices. Background Technology

[0002] During the operation of electronic / electrical equipment, insulated wires may be subjected to high-frequency voltage surges. When the local electric field strength reaches a certain value, local ionization discharge occurs, resulting in blue fluorescence at the ionization site, a phenomenon known as corona discharge. Corona discharge is accompanied by a thermal effect, causing localized temperature increases in the coil windings, leading to thermal melting or decomposition and degradation. It also produces highly oxidizing substances such as ozone and nitrogen oxides, which chemically corrode the insulation layer, accelerating the aging process. As the insulation performance continues to decline, insulation aging and short circuits occur, affecting the lifespan of the electronic / electrical equipment.

[0003] To improve the corona resistance of insulated wires, the traditional methods are: first, to thicken the insulation layer so that its insulation performance far exceeds the corona initiation voltage; and second, to add a corona-resistant layer to the insulation layer. In the current field of insulated electromagnetic wires, the corona-resistant insulation layer is mostly an enameled layer, in which corona-resistant substances are added to the insulating varnish to obtain the insulation and corona resistance function. However, this type of corona-resistant layer is a corona-resistant varnish, which requires multiple coatings and heat curing to obtain, resulting in low production efficiency.

[0004] The corona-resistant layer manufacturing process in Method 2 involves mixing a corona-resistant material with a thermoplastic resin to form a corona-resistant thermoplastic resin, followed by extrusion processing to obtain the corona-resistant layer. However, existing technologies using physical blending and coupling agent treatment to address dispersion issues still suffer from drawbacks such as weak interfacial bonding and complex processes, affecting the strength, flexibility, and other mechanical properties of the insulated wire, as well as its corona resistance. Summary of the Invention

[0005] In a first aspect, this application provides an insulated wire, comprising a conductor and an adhesive layer and an insulating layer sequentially disposed on the outside of the conductor, wherein the adhesive layer is formed by curing an adhesive, and the insulating layer comprises polyether ether ketone (PEEK) resin and corona-resistant inorganic particles, wherein the corona-resistant filler is composed of corona-resistant inorganic particles and a compatible resin coating part or all of the outer surface of the corona-resistant inorganic particles.

[0006] Furthermore, the compatible resin is phenolphthalein polyaryletherketone (PEK-C), and the phenolphthalein polyaryletherketone accounts for 0.5-5 wt% of the total weight of the corona-resistant filler.

[0007] Furthermore, the polyetheretherketone resin accounts for 65 wt% to 95 wt% of the corona-resistant resin, and the corona-resistant inorganic particles account for 5 wt% to 35 wt% of the corona-resistant resin.

[0008] Furthermore, the particle size range of the corona-resistant inorganic particles is: D90 less than 1 μm.

[0009] Furthermore, the corona-resistant inorganic particles include a first particle and a second particle; The first particle is talc; The second particle is at least one of boron nitride, mica, silicon dioxide, titanium dioxide, molybdenum disulfide, titanium oxide, aluminum oxide, calcium sulfate, calcium carbonate, ferrite, clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate, fluorocarbon resin, graphite, graphene, graphene oxide, carbon powder, ceramic powder, metal powder, flame retardant powder, nanotubes, and barium sulfate.

[0010] Furthermore, the first particle accounts for less than 5 wt% of the total mass of the corona-resistant resin; the second particle accounts for 5 wt% to 30 wt% of the total mass of the corona-resistant resin.

[0011] Furthermore, the corona-resistant inorganic particles are in the form of flakes, spheres, or irregular shapes.

[0012] Furthermore, the adhesive comprises an organic solvent, a polyamide-imide resin, and a PEEK nanopowder material.

[0013] Secondly, this application proposes a method for preparing an insulated wire, used to prepare the insulated wire in any of the above-mentioned technical solutions, comprising: Step 1: Dissolve the compatible resin in an organic solvent to obtain a primary mixture; Step 2: Add the first and second particles to the primary mixture, and disperse them evenly to obtain the secondary mixture; Step 3: The secondary mixture is made into powder to obtain a corona-resistant filler; Step 4: After mixing polyetheretherketone resin and corona-resistant filler in a certain proportion, the mixture is granulated by a twin-screw extruder to obtain corona-resistant resin particles. Step 5: Preheat the conductor; Step 6: Apply adhesive to the surface of the conductor to form an adhesive layer; Step 7: The corona-resistant resin particles obtained in Step 4 are extruded through an extruder and coated onto the surface of the adhesive layer obtained in Step 5 to form a corona-resistant insulating layer. After cooling, an insulated wire is obtained.

[0014] Furthermore, the step three of preparing the secondary mixture into powder includes: The secondary mixture is atomized, and the resulting tiny droplets are brought into contact with dry, hot air to obtain the powder.

[0015] Thirdly, this application proposes a coil composed of an insulated wire as described in any of the above technical solutions or an insulated wire prepared by the method for preparing an insulated wire as described in any of the above technical solutions.

[0016] Fourthly, this application proposes an electronic / electrical device that includes the coil described above.

[0017] The above-described technical solution of the present invention has at least the following beneficial technical effects: This application introduces inorganic particles with surface-grafted compatible resin into the corona-resistant insulating layer. Utilizing the good compatibility between the compatible resin and the PEEK matrix, the dispersibility of the corona-resistant inorganic particles and their interfacial bonding with the matrix are improved. Furthermore, the compatible resin allows for uniform mixing of PEEK and the corona-resistant inorganic particles, ensuring mutual adhesion. This helps reduce partial discharge caused by interfacial defects and enhances the corona-resistant filler's resistance to corona erosion. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of an insulated wire in one embodiment of this application.

[0019] in, Figure 1 The correspondence between the reference numerals and the component names in the attached drawings is as follows: 1. Conductor; 2. Adhesive layer; 3. Insulating layer. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0021] In a first aspect, this application provides an insulated wire, comprising a conductor 1 and an adhesive layer 2 and a corona-resistant insulating layer 3 sequentially disposed on the outer side of the conductor 1, wherein: Conductor 1 is a metallic conductor, preferably made of copper, aluminum, silver, or an alloy with copper or aluminum as the main material. The cross-section of conductor 1 can be circular, rectangular, or other irregular shapes.

[0022] Adhesive layer 2 is formed by the curing of an adhesive to address the problem of low adhesion between polyetheretherketone (PEEK) resin and the metal conductor 1. The main components of the adhesive are organic solvents, polyamide-imide resin, and PEEK nanopowder material. It exhibits good metal adhesion and compatibility with PEEK resin, preventing interlayer delamination under thermal stress or corona discharge, thus ensuring long-term operational stability. The thickness of the adhesive layer is 5μm-30μm; preferably 10μm or more but less than 20μm.

[0023] Insulating layer 3, covering the outer side of adhesive layer 2, comprises PEEK and corona-resistant filler. The corona-resistant filler consists of corona-resistant inorganic particles and a compatible resin coating part or all of the outer surface of the particles. PEEK, as the matrix material of insulating layer 3, possesses characteristics such as high temperature resistance, chemical corrosion resistance, high mechanical strength, and excellent insulation performance, giving it high corona resistance. The addition of corona-resistant filler further enhances the corona resistance. Furthermore, the introduction of corona-resistant inorganic particles with surface grafted compatibility resin into insulating layer 3, which is primarily composed of PEEK, improves the dispersibility of the corona-resistant inorganic particles and their interfacial bonding with the matrix by utilizing the good compatibility between the resin and the PEEK matrix. The compatibility resin also allows for uniform mixing of PEEK and corona-resistant inorganic particles, ensuring adhesion between them, reducing partial discharge caused by interfacial defects, and enhancing the corona-resistant filler's resistance to corona erosion. Good interfacial bonding makes stress transfer more efficient and reduces the occurrence of reduced flexibility and decreased mechanical strength caused by the agglomeration of corona-resistant fillers.

[0024] Preferably, the compatible resin is phenolphthalein-based polyaryletherketone (PEK-C). The phenolphthalein side bonds of PEK-C make it soluble in solvents. The ether and ketone bonds on PEK-C have similar molecular structures to those on PEEK, thus exhibiting good compatibility. PEK-C is soluble in solvents, resulting in low solution viscosity, allowing for nanoscale uniform dispersion of corona-resistant inorganic particles in the PEK-C solution. Phenolphthalein-based polyaryletherketone accounts for 0.5-5 wt% of the total weight of the corona-resistant filler, ensuring the formation of a complete and effective connecting layer or modified layer on the surface of the corona-resistant inorganic particles, thereby improving the dispersibility and interfacial bonding effect of the filler. Too low a PEK-C proportion results in incomplete coating and poor performance, while too high a proportion may increase melt viscosity, requiring higher processing temperatures or longer processing times.

[0025] Preferably, the polyetheretherketone resin accounts for 65 wt% to 95 wt% of the corona-resistant resin, and the corona-resistant inorganic particles account for 5 wt% to 35 wt% of the corona-resistant resin. Adding too high a proportion of corona-resistant material to the corona-resistant resin will cause the resin to harden and lose flexibility, which is detrimental to the bending and processing of insulated wires. Adding too low a proportion will result in a lack of corona resistance even with a thin coating.

[0026] Preferably, the particle size range of the corona-resistant inorganic particles is: D90 less than 1μm, which is beneficial to their uniform dispersion in the resin and reduces the local electric field concentration caused by large particles.

[0027] Nanoscale corona-resistant inorganic particles have a larger specific surface area, which can more effectively scatter and absorb partial discharge energy, inhibit the initiation and growth of electrical trees, and thus significantly improve corona resistance.

[0028] Preferably, the corona-resistant inorganic particles include a first particle and a second particle; the first particle is talc; the main function of talc is to improve the processing fluidity of the insulating layer 3, while not affecting the flexibility and corona resistance of the insulating layer 3.

[0029] The second particle comprises at least one of the following: boron nitride, mica, silicon dioxide, titanium dioxide, molybdenum disulfide, titanium oxide, aluminum oxide, calcium sulfate, calcium carbonate, ferrite, clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate, fluorocarbon resin, graphite, graphene, graphene oxide, carbon powder, ceramic powder, metal powder, flame retardant powder, nanotubes, and barium sulfate. The second particle primarily provides corona resistance.

[0030] Furthermore, the proportion of the first particle in the insulating layer 3 is less than 5 wt%; the proportion of the second particle in the total mass of the corona-resistant resin is 5 wt% to 30 wt%. Talc has a plate-like structure, and adding a small amount helps to form a barrier, but excessive amounts will affect the flexibility and processing performance of the material.

[0031] Furthermore, the corona-resistant inorganic particles are in the form of flakes, spheres, or irregular shapes.

[0032] Furthermore, the adhesive includes organic solvents, polyamide-imide resins, and PEEK nanopowder materials.

[0033] Secondly, this application proposes a method for preparing an insulated wire, used to prepare the insulated wire in any of the above-mentioned technical solutions, comprising: Step 1: Dissolve the compatible resin in an organic solvent to obtain a primary mixture. The organic solvent is N,N-dimethylacetamide (DMAc).

[0034] Step 2: Add the first and second particles to the primary mixture, and disperse them evenly to obtain the secondary mixture.

[0035] Step 3: The secondary mixture is powdered to obtain a corona-resistant filler; wherein, the powdering of the secondary mixture in step 3 includes: The secondary mixture is atomized, and the resulting tiny droplets are brought into contact with dry, hot air to obtain a powder. This step allows for a more uniform coating of the compatible resin on the surface of the corona-resistant inorganic particles, while avoiding damage to the coating layer or particle re-agglomeration that may occur with traditional grinding processes.

[0036] Step 4: After mixing polyetheretherketone resin and corona-resistant filler in a certain proportion, the mixture is blended and granulated using a twin-screw extruder to obtain corona-resistant resin particles.

[0037] Step 5: Preheat the conductor to a temperature above 400℃.

[0038] Step 6: Apply adhesive to the surface of the conductor 1 to form an adhesive layer 2.

[0039] Step 7: The corona-resistant resin particles obtained in Step 4 are extruded and coated onto the surface of the adhesive layer obtained in Step 5 using an extruder to form a corona-resistant insulating layer. After cooling, an insulated wire is obtained. The thickness of the insulating layer 3 is 1-300 μm.

[0040] Thirdly, this application proposes a coil composed of an insulated wire as described in any of the above technical solutions or an insulated wire prepared by the method for preparing an insulated wire as described in any of the above technical solutions. Therefore, the coil possesses all the advantages and beneficial effects of the aforementioned insulated wires, which will not be elaborated here.

[0041] Fourthly, this application proposes an electronic / electrical device that includes the coil described above.

[0042] The following specific embodiments are further illustrations of this application. The examples given do not represent all the implementation methods of this application; only some are used as examples for illustration. Specific embodiments are as follows: Example 1

[0043] The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer thickness is 110-130μm. The corona-resistant inorganic particles in the insulation layer are talc and silica, with the particles comprising 20wt% of the total content; of which talc accounts for 4wt%; the D90 particle size range is 5-950nm. PEK-C constitutes 3wt% of the corona-resistant inorganic particles; the remainder of the insulation layer is PEEK. Example 2

[0044] The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer is 110-130μm thick. The corona-resistant inorganic particles in the insulation layer are talc and silica, with the particles comprising 30wt%; of which talc accounts for 4wt%; the D90 particle size ranges from 5-950nm. PEK-C comprises 5wt% of the corona-resistant inorganic particles; the remainder in the insulation layer is PEEK. Example 3

[0045] The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer thickness is 110-130μm. The corona-resistant inorganic particles in the insulation layer are talc and boron nitride, with a corona-resistant inorganic filler content of 5wt%; of which talc accounts for 4wt%; the D90 particle size range is 5-950nm. PEK-C comprises 0.5wt% of the corona-resistant inorganic particles; the remainder in the insulation layer is PEEK.

[0046] Comparative Example 1 The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer is 110-130μm thick. No corona-resistant inorganic particles or PEK-C are added to the insulation layer. The insulation layer is PEEK.

[0047] Comparative Example 2 The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer is 110-130μm thick. The corona-resistant inorganic particles in the insulation layer are talc and silica, with the particles comprising 50wt%; of which talc accounts for 4wt%; the D90 particle size ranges from 5-950nm. PEK-C comprises 5wt% of the corona-resistant inorganic particles; the remainder in the insulation layer is PEEK.

[0048] Comparative Example 3 The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer thickness is 110-130μm. The corona-resistant inorganic particles in the insulation layer are talc and silica, with the particles accounting for 20wt%; of which talc accounts for 4wt%; the D90 particle size range is 5-950nm. No PEK-C was added; the remaining material in the insulation layer is PEEK.

[0049] Comparative Example 4 The insulated wire has copper conductors measuring 1.6mm × 2.0mm; the insulation layer is 110-130μm thick. The corona-resistant inorganic particles in the insulation layer are talc and silica, with the particles comprising 20wt% of the total content; of which talc accounts for 4wt%; the D90 particle size ranges from 3000-5000nm. PEK-C comprises 3wt% of the corona-resistant inorganic particles; the remainder in the insulation layer is PEEK.

[0050] The insulated wires of the above embodiments and comparative examples were tested according to the following methods: (1) Corona resistance time test method: The test method of GB / T4074.21 was adopted, and the specific steps are as follows: the insulated wires in Examples 1-3 and Comparative Examples 1-4 were placed in a high-frequency pulse voltage test instrument, and a high-frequency pulse voltage was applied between the two conductors of the sample under the following conditions, and the time (h) elapsed from the start of voltage application to the breakdown of the insulation layer was recorded.

[0051] Test conditions: pulse frequency 20kHz, pulse duty cycle 50%, pulse square wave, bipolar pulse, test voltage 1.5kV, temperature 155℃, rise time 100ns.

[0052] The evaluation criteria are as follows: A: Corona resistance time ≥200h; B: Corona resistance time ≥50h and <200h; C: Corona resistance time < 50h.

[0053] In this case, A represents qualified, and the others represent unqualified.

[0054] (2) Insulation breakdown voltage (BDV) test: The test shall be conducted according to the breakdown voltage test method provided in IEC 60851-5-2019 Test Method 13. The specific steps are as follows: Remove the outer layer from one end of the insulated wire in Examples 1-3 and Comparative Examples 1-4, and leave a diameter of... After bending the wider side of a 25mm round rod, place it into a container of metal balls at least 5mm thick, ensuring the insulated wire end extends sufficiently to prevent flashover. Apply a test voltage between the conductor and the metal balls. Increase the voltage at a rate of 500V / second and a leakage current of 5mA. Record the breakdown voltage (kV) and classify it according to the following method: A+: BDV ≥ 11kV; A: BDV ≥ 9kV and < 11kV; B: BDV ≥ 7kV and < 9kV; C: BDV < 7kV; A+ and A are considered qualified, while the others are considered unqualified.

[0055] (3) Flexibility test: The flexibility test shall be conducted according to the flexibility test method provided in IEC 60851-3-2019 Test Method 8. The specific steps are as follows: Take two 500mm long straight insulated wires and bend each wire 180±2° around a polished test core. One wire is wound horizontally (core diameter = wire thickness twice), and the other is wound vertically (core diameter = wire width twice). In this test, after horizontal and vertical winding, a product with a smooth, crack-free surface is recorded as "qualified"; a product with surface cracks is recorded as "unqualified".

[0056] Table 1 Performance of insulated wires in the examples and comparative examples

[0057] As shown in Table 1, the insulated wires of Examples 1-3 all met the qualification requirements of the three tests: corona resistance time reached Grade A (≥200h), breakdown voltage (BDV) reached Grade A or A+ (≥9kV), and the flexibility test was qualified (no cracking when wound flat and vertically). However, Comparative Examples 1-4 all failed at least one of the indicators. The core differences stemmed from the proportion of corona-resistant inorganic particles, the presence or absence of PEK-C, and the appropriateness of the particle size.

[0058] (1) Corona resistance time: In Examples 1-3, the proportion of corona-resistant inorganic particles was 5-30wt%, and all achieved Class A corona resistance time (≥200h). This proportion range allows the particles to form a continuous corona-resistant protective network in the PEEK resin, effectively blocking corona erosion.

[0059] Comparative Example 1 had 0 wt% inorganic corona-resistant particles and no protective network, with a corona resistance time of <50h (Grade C). This indicates that the inorganic corona-resistant particles are the core functional carrier for corona resistance performance. Comparative Example 2 had 50 wt% inorganic particles, far exceeding 30 wt%. Particle agglomeration led to an uneven protective network, resulting in a corona resistance time of only Grade B (≥50h and <200h), which also caused subsequent failures in flexibility and BDV.

[0060] In Examples 1-3, 0.5-5 wt% of PEK-C was added. PEK-C, as an interfacial compatibilizer, can reduce particle agglomeration and achieve uniform dispersion.

[0061] Comparative Example 3, due to the absence of PEK-C, even with a corona-resistant inorganic particle content of 20wt%, still suffered from weak local protection due to particle agglomeration, resulting in a corona resistance time of grade B. This verifies the crucial role of PEK-C in dispersion uniformity and corona resistance performance.

[0062] The D90 of the corona-resistant inorganic particles in Examples 1-3 is 5-950nm, ensuring that the vast majority of particles are at the submicron scale, effectively avoiding local electric field distortion and mechanical weaknesses caused by the presence of large-sized particles, and can uniformly construct a protective network.

[0063] Comparative Example 4 shows that the corona-resistant inorganic particles have a particle size range of 3000-5000nm. Large-sized particles are prone to becoming defects and are difficult to be effectively coated and dispersed, resulting in a large number of weak points in the insulation layer, which become weak points in corona discharge. The corona resistance time is <50h (Grade C).

[0064] (2) Breakdown voltage (BDV): BDV reflects the ability of the insulation layer to resist electric field breakdown. Whether it is qualified or not depends on the integrity of the internal structure of the insulation layer.

[0065] Examples 1-3, with a particle content of 5-30 wt%, did not disrupt the continuity of the PEEK resin matrix, and all had a BDV ≥ 9 kV (A or A+ grade). Among them, Example 3, with a boron nitride content of 5 wt%, exhibited the best performance due to its more uniform particle dispersion and fewer internal defects, resulting in a BDV ≥ 11 kV (A+ grade).

[0066] Comparative Example 2 had a corona-resistant inorganic particle content of 50 wt%. Excessive particles disrupted the continuity of the resin, forming a large number of stress concentration points and voids inside, with a BDV < 7 kV (Grade C). Comparative Example 4 had large-diameter particles. Due to particle agglomeration, air gaps were generated, and the electric field was concentrated, resulting in a BDV < 7 kV (Grade C). Both the proportion and particle size did not meet the qualification requirements.

[0067] Comparative Example 3, without the addition of PEK-C, showed particle agglomeration forming minor defects, but did not severely disrupt the matrix continuity, and the BDV was still ≥9kV (Grade A). This indicates that PEK-C mainly affects corona resistance performance, and its impact on BDV is weaker than the proportion and particle size of inorganic particles in corona resistance.

[0068] In Examples 1-2, due to the moderate particle ratio and the absence of obvious internal defects, the BDV remained stable at level A, effectively ensuring insulation strength.

[0069] (3) Flexibility test: In Examples 1-3, the proportion of corona-resistant inorganic particles was ≤30wt%, the PEEK resin matrix maintained good continuity, and the flexibility test was qualified.

[0070] Comparative Example 2: The proportion of corona-resistant inorganic particles was 50 wt%. Excessive particles caused the resin matrix to become brittle, and stress concentration during bending led to cracking (unqualified). This proves that the proportion of corona-resistant inorganic particles exceeding the critical value will significantly deteriorate the flexibility.

[0071] Examples 1-3 show corona-resistant inorganic particles with a D90 ≤ 950 nm. These small-diameter particles can tightly bond with PEEK resin, disperse stress, and do not crack when bent.

[0072] Comparative Example 4: The corona-resistant inorganic particles have a particle size range of 3000-5000 nm. The large-diameter particles have weak bonding force with PEEK, which causes stress concentration when bent, resulting in surface cracking (unqualified).

[0073] Comparative Example 3, without the addition of PEK-C, showed agglomeration of corona-resistant inorganic particles, but the proportion was 20wt% (≤35%), and the flexibility was still acceptable. The proportion and particle size of corona-resistant inorganic particles are the main factors affecting flexibility, and PEK-C indirectly optimizes flexibility.

[0074] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this application and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this application should be included within the protection scope of this application. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. An insulated wire, comprising a conductor and an adhesive layer and a corona-resistant insulating layer sequentially disposed on the outer side of the conductor, wherein the adhesive layer is formed by curing an adhesive, characterized in that, The corona-resistant insulating layer is obtained by melt extrusion of corona-resistant resin, which includes polyetheretherketone resin and corona-resistant filler. The corona-resistant filler is composed of corona-resistant inorganic particles and a compatible resin that coats part or all of the outer surface of the corona-resistant inorganic particles.

2. The insulated wire according to claim 1, characterized in that, The compatibility resin is phenolphthalein polyaryletherketone, and the phenolphthalein polyaryletherketone accounts for 0.5-5 wt% of the total weight of the corona-resistant filler.

3. The insulated wire according to claim 1, characterized in that, The polyetheretherketone resin accounts for 65 wt% to 95 wt% of the corona-resistant resin, and the corona-resistant inorganic particles account for 5 wt% to 35 wt% of the corona-resistant resin.

4. The insulated wire according to claim 1, characterized in that, The particle size range of the corona-resistant inorganic particles is: D90 less than 1 μm.

5. The insulated wire according to claim 1, characterized in that, The corona-resistant inorganic particles include a first particle and a second particle; The first particle is talc; The second particle is at least one of boron nitride, mica, silicon dioxide, titanium dioxide, molybdenum disulfide, titanium oxide, aluminum oxide, calcium sulfate, calcium carbonate, ferrite, clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate, fluorocarbon resin, graphite, graphene, graphene oxide, carbon powder, ceramic powder, metal powder, flame retardant powder, nanotubes, and barium sulfate.

6. The insulated wire according to claim 5, characterized in that, The first particle accounts for less than 5 wt% of the total mass of the corona-resistant resin; the second particle accounts for 5 wt% to 30 wt% of the total mass of the corona-resistant resin.

7. The insulated wire according to claim 5, characterized in that, The corona-resistant inorganic particles are in the form of flakes, spheres, or irregular shapes.

8. The insulated wire according to claim 1, characterized in that, The adhesive comprises an organic solvent, a polyamide-imide resin, and a PEEK nanopowder material.

9. A method for preparing an insulated wire, used to prepare the insulated wire according to any one of claims 5-8, characterized in that, include: Step 1: Dissolve the compatible resin in an organic solvent to obtain a primary mixture; Step 2: Add the first and second particles to the primary mixture, and disperse them evenly to obtain the secondary mixture; Step 3: The secondary mixture is made into powder to obtain a corona-resistant filler; Step 4: After mixing polyetheretherketone resin and corona-resistant filler in a certain proportion, the mixture is granulated by a twin-screw extruder to obtain corona-resistant resin particles. Step 5: Preheat the conductor; Step 6: Apply adhesive to the surface of the conductor to form an adhesive layer; Step 7: The corona-resistant resin particles obtained in Step 4 are extruded through an extruder and coated onto the surface of the adhesive layer obtained in Step 6 to form a corona-resistant insulating layer. After cooling, an insulated wire is obtained.

10. The method for preparing an insulated wire according to claim 9, characterized in that, Step three, which involves preparing the secondary mixture into powder, includes: The secondary mixture is atomized, and the resulting tiny droplets are brought into contact with dry, hot air to obtain the powder.

11. A coil, characterized in that, It comprises an insulated wire made by any one of claims 1-8 or an insulated wire made by any one of claims 9-10.

12. An electronic / electrical device, characterized in that, Includes the coil as described in claim 11.

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