Multi-layer copper-clad ceramic coil for axial flux motor and preparation method of multi-layer copper-clad ceramic coil

Abstract

The invention discloses a multilayer copper-clad ceramic coil for an axial magnetic flux motor and a preparation method, and relates to the technical field of design and manufacturing of stator coils of axial magnetic flux motors. The multilayer copper-clad ceramic coil is prepared through the steps of ceramic chip punching, copper particle embedding, copper coil metallization, alternate lamination, vacuum diffusion welding and the like, and the coil is prepared through the vacuum diffusion welding technology. The defects of an existing PCB coil and an enameled wire winding coil in the aspects of temperature resistance, heat conductivity, mechanical strength, current bearing capacity, reliability and the like are overcome. The multilayer copper-clad ceramic coil prepared by the invention has the advantages of high temperature resistance, high heat conduction capability, high current bearing capability, high binding force between the coil and a base material, high mechanical strength and the like, and can effectively balance the power density, the heat dissipation efficiency and the mechanical reliability of an axial magnetic flux motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of axial flux motor stator coil design and manufacturing, in particular to a multilayer copper-clad ceramic coil for axial flux motor and a preparation method thereof. BACKGROUND

[0002] Axial flux motors are widely used in hub motors, aircraft power, new energy vehicles and robot joints due to their short axial magnetic circuit and high torque density. However, the existing stator coil scheme of axial flux motors still has many technical bottlenecks, which is difficult to meet the comprehensive needs of high power density, high heat dissipation efficiency and long-term reliable operation.

[0003] Currently, there are two types of structures for traditional stator coils: one is PCB (printed circuit board) printed winding, and the other is enameled wire winding. In practical applications, both have obvious defects: heat is conducted through epoxy resin or polyimide insulation layer, which has a low thermal conductivity (<0.5 W / m·K), resulting in high coil temperature rise (>100℃), accelerating insulation aging and limiting power density. Limited by the material of the PCB substrate, the PCB coil has poor temperature resistance and cannot be used in scenarios above 200℃. Moreover, the mechanical strength and the bonding strength between the copper foil and the substrate are low, and there is a risk of voids and failure due to temperature changes during long-term service. The existing axial motor coil scheme cannot balance power density, heat dissipation efficiency and mechanical reliability, and there is an urgent need for a comprehensive solution that integrates material, structure and process innovation.

[0004] In order to solve the problems existing in the coil of the axial flux motor in the prior art, the present application provides a multilayer copper-clad ceramic coil for axial flux motor and a preparation method thereof. SUMMARY

[0005] The purpose of the present application is to provide a multilayer copper-clad ceramic coil for axial flux motor and a preparation method thereof to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] The multilayer copper-clad ceramic coil for axial flux motor is a multilayer repeated structure arranged in a fixed order from top to bottom, the fixed order being copper coil layer, welding layer, ceramic sheet, welding layer, copper coil layer; the copper coil layer and the ceramic sheet are connected through the welding layer.

[0008] Further, the ceramic sheet is provided with a conductive through hole, and a copper particle is embedded in the conductive through hole to form a conductive path.

[0009] Further, the copper coil layer includes a copper coil and a metal layer, the metal layer includes a titanium metal layer and a nickel metal layer, the titanium metal layer is on the surface of the copper coil, and the nickel metal layer is on the surface of the titanium metal layer.

[0010] The preparation method of the multilayer copper-clad ceramic coil for an axial flux motor comprises the following steps:

[0011] S1: porcelain sheet punching, copper coil preparation: punch holes on the porcelain sheet where the conductive via is needed, form conductive vias for positioning, fixing and conductive via; at the same time, make copper coils;

[0012] S2: embed copper particles in the porcelain sheet holes: embed copper particles in the conductive vias of the porcelain sheet;

[0013] S3: prepare a metallized coil: sequentially and uniformly plate a titanium metal layer and a nickel metal layer on the surface of the copper coil to obtain a metallized coil for subsequent diffusion welding;

[0014] S4: lamination: alternately align and laminate the metallized coil and the porcelain sheet with embedded copper particles to form a multilayer structure with the metallized coil and the porcelain sheet alternately inserted as shown in Figure 6 for subsequent diffusion welding;

[0015] S5: vacuum diffusion welding: place the multilayer structure in a vacuum diffusion welding furnace and use pressure diffusion welding technology to diffusion weld the multilayer structure to form a welding layer between the copper coil layer and the porcelain sheet, thereby obtaining a multilayer copper-clad ceramic coil.

[0016] Further, in step S1, the porcelain sheet uses the commonly used ceramic of copper-clad ceramic substrate, which is one of alumina, silicon nitride and aluminum nitride;

[0017] The method for making the copper coil is one of laser, etching and die punching.

[0018] Further, in step S2, the height of the copper particles is 0-10μm less than the thickness of the porcelain sheet, and the diameter of the copper particles is 0-30μm less than the diameter of the ceramic hole, so that the copper particles can be diffusion welded with the metallized copper coil in the subsequent welding process, and the conductive property of the via in the subsequent welding process is ensured.

[0019] Further, in step S3, the titanium and nickel metal layers are plated on the surface of the copper coil by one of the methods of magnetron sputtering, evaporation, spraying, electroplating and chemical plating;

[0020] The thickness of the titanium metal layer is 0.3μm-4μm, and the thickness of the nickel metal layer is 0.1-2μm.

[0021] Further, in step S5, the process conditions of the pressure diffusion welding technology are as follows: welding temperature 770-870℃, pressure 4-8MPa, and high-temperature pressure welding time 60-600min.

[0022] Further, Figure 5 as shown in Figure 3The conductive via positions are one-to-one corresponding to realize the series connection of the positive and negative coils after welding.

[0023] In the technical scheme, the edge position of the copper coil is widened and lengthened to be used for welding the lead wire, so as to avoid affecting the air gap of the stator and rotor where the coil is located.

[0024] In the technical scheme, it is necessary to pay attention to the matching use of the metallized coil and the porcelain sheet with pre-embedded copper particles to ensure that the magnetic field directions generated by the multi-layer coil in series connection are the same.

[0025] In the technical scheme, the welding is realized without the appearance of the metal liquid phase in the S5 welding process, the dimensional accuracy of the pattern is ensured, and the uniformity of the magnetic field strength and the reliability of the overall device are ensured.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] 1. The multi-layer copper-clad ceramic coil for an axial flux motor and the preparation method thereof adopt ceramic as a base material, and the ceramic has good high-temperature resistance, so that the coil can stably work in a high-temperature environment above 200 DEG C, overcomes the defect of poor temperature resistance of a PCB coil, and improves the temperature resistance of the coil.

[0028] 2. The multi-layer copper-clad ceramic coil for an axial flux motor and the preparation method thereof, the thermal conductivity of the PCB coil base material (FR4, etc.) is only 0.3 W / (m*K), and the base material used in the present application is silicon nitride or aluminum nitride ceramic, and the thermal conductivity is 80-170 W / (m*K), so that the heat of the stator coil can be quickly transmitted to the machine shell, thereby reducing the heat conduction to the permanent magnet rotor with air flow, greatly reducing the temperature rise of the permanent magnet rotor, and further reducing the attenuation of the rotor magnetic performance, and protecting the heat dissipation capacity and performance stability of the device.

[0029] 3. The multi-layer copper-clad ceramic coil for an axial flux motor and the preparation method thereof, the existing axial flux motor PCB stator is limited by the thickness of the copper foil, and the current carrying capacity is usually below 200 mu m, and there are problems of large winding resistance, poor current carrying capacity and the like; and the winding coil of the multi-layer copper-clad ceramic coil can be made of a single 1.2 mm thick copper, which will greatly reduce the resistance and copper loss (power consumed due to copper coil resistance) of the winding, and due to the increase of the cross-sectional area of the copper, the current carrying capacity can be greatly improved.

[0030] 4, The multilayer copper-clad ceramic coil for axial flux motor and the preparation method thereof, the connection between the copper coil and the ceramic base material is realized by using the metal diffusion welding technology, the joint strength is close to the base material, the bonding force between the coil and the base material is much stronger than the PCB, and the ceramic itself has high mechanical strength, which ensures that the coil is not easy to produce cavities and failure during long-term service even under the influence of temperature change, and better reliability is ensured; The peeling strength of the copper layer and the ceramic of the multilayer copper-clad ceramic coil of the application is greater than 15N / mm, and the peeling strength of the copper layer and the PCB base material of the PCB coil is only about 1N / mm. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The preparation process flow chart of the multilayer copper-clad ceramic coil of the application;

[0032] Figure 2 The appearance schematic diagram of the multilayer copper-clad ceramic coil of the application;

[0033] Figure 3 The relative position schematic diagram of the via hole of the multilayer copper-clad ceramic coil of the application;

[0034] Figure 4 The schematic diagram of the metallized copper coil of the multilayer copper-clad ceramic coil of the application;

[0035] Figure 5 The schematic diagram of the porcelain chip of the pre-embedded copper particle of the multilayer copper-clad ceramic coil of the application;

[0036] Figure 6 The schematic diagram of the via hole and the laminated structure of the multilayer copper-clad ceramic coil of the application;

[0037] Figure 7 The SEM diagram of the copper-porcelain interface of the multilayer copper-clad ceramic coil after diffusion welding of the application;

[0038] In the figure: 1 is a conductive via hole; 2 is a copper particle; 3 is a metallized coil; 4 is a porcelain chip; 5 is a copper coil layer; 6 is a welding layer. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0040] Embodiment 1: A multi-layer copper-clad ceramic coil for an axial flux motor, which is a multi-layer repeated structure arranged in a fixed order from top to bottom, the fixed order being copper coil layer 5, welding layer 6, ceramic sheet 4, welding layer 6, and so on copper coil layer 5; the copper coil layer 5 and the ceramic sheet 4 are connected through the welding layer 6; the ceramic sheet 4 is provided with a conductive through hole 1, and a copper particle 2 is embedded in the conductive through hole 1; the copper coil layer 5 comprises a copper coil and a metal layer, the metal layer comprises a titanium metal layer and a nickel metal layer, the titanium metal layer is on the surface of the copper coil, and the nickel metal layer is on the surface of the titanium metal layer.

[0041] A method for preparing a multi-layer copper-clad ceramic coil for an axial flux motor, comprising the following steps:

[0042] S1: ceramic sheet punching and copper coil preparation: using a fiber laser cutting machine to punch a conductive through hole 1 at the position where the 0.25mm silicon nitride ceramic sheet 4 needs a through hole for conduction; at the same time, a copper coil is made by die cutting, with a copper thickness of 0.2mm and a wire width of 0.3mm; the laser parameters are: power 1kW, cutting speed 5mm / s, frequency 100kHz, duty cycle 50%, nitrogen flow rate 30m 3 / h, pressure 0.5MPa;

[0043] S2: embedding copper particles in ceramic sheet holes: embedding copper particles 2 in the conductive through hole 1 of the ceramic sheet, the height of the copper particles being consistent with the thickness of the ceramic sheet, i.e. 0.2mm;

[0044] S3: preparation of metallized coil: using a magnetron sputtering device to uniformly coat a titanium metal layer and a nickel metal layer on the front and back surfaces of the copper coil in sequence, the thickness of the titanium metal layer being 1μm and the thickness of the nickel metal layer being 0.5μm, to obtain a metallized coil 3; the process conditions of magnetron sputtering are: vacuum degree 2x10 -4 Pa, argon pressure 0.1Pa, sputtering power 12kW, voltage 600V, time 60min, and sputtering temperature 350℃;

[0045] S4: lamination: alternately aligning and laminating the metallized coil 3 and the ceramic sheet 4 with embedded copper particles 2 to form a multi-layer structure in which the metallized coil 3 and the ceramic sheet 4 are alternately inserted;

[0046] S5: vacuum diffusion welding: placing the multi-layer structure in a vacuum diffusion welding furnace and using pressure diffusion welding technology to diffusion weld the multi-layer structure to form a welding layer 6 between the copper coil layer 5 and the ceramic sheet 4, thereby obtaining a multi-layer copper-clad ceramic coil; the welding process conditions are: welding temperature 820℃, pressure 7MPa, and high-temperature pressure welding time 120min.

[0047] Embodiment 2: A multi-layer copper-clad ceramic coil for an axial flux motor, which is a multi-layer repeated structure arranged in a fixed order from top to bottom, the fixed order being copper coil layer 5, welding layer 6, ceramic sheet 4, welding layer 6, and so on copper coil layer 5; the copper coil layer 5 and the ceramic sheet 4 are connected through the welding layer 6; the ceramic sheet 4 is provided with a conductive through hole 1, and a copper particle 2 is embedded in the conductive through hole 1; the copper coil layer 5 comprises a copper coil and a metal layer, the metal layer comprises a titanium metal layer and a nickel metal layer, the titanium metal layer is on the surface of the copper coil, and the nickel metal layer is on the surface of the titanium metal layer.

[0048] A method for preparing a multi-layer copper-clad ceramic coil for an axial flux motor, comprising the following steps:

[0049] S1: ceramic sheet punching and copper coil preparation: a fiber laser cutting machine is used to punch a conductive through hole 1 at a position where a through hole is needed on a 0.25 mm silicon nitride ceramic sheet 4; at the same time, a copper coil is made by die cutting, with a copper thickness of 0.2 mm and a wire width of 0.3 mm; the laser parameters are: power 1 kW, cutting speed 5 mm / s, frequency 100 kHz, duty cycle 50%, nitrogen flow rate 30 m 3 / h, pressure 0.5 MPa;

[0050] S2: embedding copper particles in ceramic sheet holes: embedding a copper particle 2 in the conductive through hole 1 of the ceramic sheet, the height of the copper particle being consistent with the thickness of the ceramic sheet, i.e. 0.2 mm;

[0051] S3: preparation of a metalized coil: using a magnetron sputtering device to uniformly coat a titanium metal layer and a nickel metal layer on the front and back surfaces of the copper coil in sequence, the thickness of the titanium metal layer being 1 μm and the thickness of the nickel metal layer being 0.5 μm, to obtain a metalized coil 3; the process conditions of the magnetron sputtering are: vacuum degree 2 x 10 -4 Pa, argon pressure 0.1 Pa, sputtering power 12 kW, voltage 600 V, time 60 min, and sputtering temperature 350℃;

[0052] S4: lamination: alternately aligning and laminating the metalized coil 3 and the ceramic sheet 4 with the embedded copper particles 2 to form a multi-layer structure in which the metalized coil 3 and the ceramic sheet 4 are alternately inserted;

[0053] S5: vacuum diffusion welding: placing the multi-layer structure in a vacuum diffusion welding furnace and using pressure diffusion welding technology to diffusion weld the multi-layer structure to form a welding layer 6 between the copper coil layer 5 and the ceramic sheet 4, thereby obtaining a multi-layer copper-clad ceramic coil; the welding process conditions are: welding temperature 770℃, pressure 4 MPa, and high-temperature pressure welding time 600 min.

[0054] Embodiment 3: A multi-layer copper-clad ceramic coil for an axial flux motor, which is a multi-layer repeated structure arranged in a fixed order from top to bottom, the fixed order being copper coil layer 5, welding layer 6, ceramic sheet 4, welding layer 6, and so on copper coil layer 5; the copper coil layer 5 and the ceramic sheet 4 are connected through the welding layer 6; the ceramic sheet 4 is provided with a conductive through hole 1, and a copper particle 2 is embedded in the conductive through hole 1; the copper coil layer 5 comprises a copper coil and a metal layer, the metal layer comprises a titanium metal layer and a nickel metal layer, the titanium metal layer is on the surface of the copper coil, and the nickel metal layer is on the surface of the titanium metal layer.

[0055] A preparation method of a multi-layer copper-clad ceramic coil for an axial flux motor, comprising the following steps:

[0056] S1: ceramic sheet punching and copper coil preparation: using a fiber laser cutting machine to punch a hole in the position where the 0.25mm silicon nitride ceramic sheet 4 needs a conductive through hole, forming a conductive through hole 1; at the same time, a copper coil is made by die cutting, the copper thickness is 0.2mm, the wire width is 0.3mm; the laser parameters are: power 1kW, cutting speed 5mm / s, frequency 100kHz, duty cycle 50%, nitrogen flow 30m 3 / h, pressure 0.5MPa;

[0057] S2: embedding copper particles in ceramic sheet holes: embedding copper particles 2 in the conductive through hole 1 of the ceramic sheet, the height of the copper particles is consistent with the thickness of the ceramic sheet, which is 0.2mm;

[0058] S3: preparation of metallized coil: using a magnetron sputtering device to uniformly coat a titanium metal layer and a nickel metal layer on the front and back surfaces of the copper coil in turn, the thickness of the titanium metal layer is 1μm, and the thickness of the nickel metal layer is 0.5μm, to obtain a metallized coil 3; the process conditions of magnetron sputtering are: vacuum degree 2×10 -4 Pa, argon pressure 0.1Pa, sputtering power 12kW, voltage 600V, time 60min, sputtering temperature 350℃;

[0059] S4: lamination: alternately aligning and laminating the metallized coil 3 and the ceramic sheet 4 with embedded copper particles 2 to form a multi-layer structure in which the metallized coil 3 and the ceramic sheet 4 are alternately inserted;

[0060] S5: vacuum diffusion welding: placing the multi-layer structure in a vacuum diffusion welding furnace, and using pressure diffusion welding technology to diffusion weld the multi-layer structure to form a welding layer 6 between the copper coil layer 5 and the ceramic sheet 4, and obtain a multi-layer copper-clad ceramic coil; the welding process conditions are: welding temperature 870℃, pressure 8MPa, high-temperature pressure welding time 60min.

[0061] Comparative Example 1: A coil is prepared by using a PCB (printed circuit board) printed winding, which forms a coil pattern by etching copper foil on an insulating substrate, and the specific process is as follows:

[0062] S1: substrate pretreatment: select epoxy glass cloth substrate as the base material, according to the coil design size, cut the substrate, clean the substrate at 40 kHz ultrasonic frequency, 50 ℃ for 5 min; then dry at 80 ℃ for 40 min;

[0063] S2: copper cladding and pattern transfer: adopt calendering method, cover uniform copper foil on the surface of the substrate at 160 ℃, pressure 20 MPa, the thickness of the copper foil is 35 μm, form copper clad plate; the designed pattern is transferred to the surface of the copper clad plate by photoetching technology: apply a layer of photosensitive resist AZ 4620 on the copper foil, then expose to ultraviolet light, accurately print the circuit pattern on the resist, remove the unexposed area of the photosensitive resist with 0.8% sodium hydroxide solution, and develop the target pattern;

[0064] S3: etching forming: use ferric chloride solution to etch the copper clad plate at 45 ℃, form the coil pattern; after etching, remove the residual resist with 5% NaOH solution, get the single layer PCB coil;

[0065] S4: multi-layer structure manufacturing: stack the insulating layer and the new copper clad plate on the basis of the single layer coil, press at 170 ℃, 25 MPa to realize the interlayer bonding; use drilling and copper plating process to manufacture interlayer conductive via, make the multi-layer coil realize electrical connection, and prepare the coil.

[0066] Comparative example 2: use enameled wire winding to prepare the coil, wind the insulating enameled wire into the coil by automatic equipment, the specific process is as follows:

[0067] S1: enameled wire selection and pretreatment: coat polyimide paint insulating layer on the surface of the copper wire, the wire diameter is 1 mm; control the wire tension of the enameled wire, the tension is 10 N, to avoid breakage or damage to the insulating layer during winding;

[0068] S2: winding forming: use full-automatic winding machine, wind the enameled wire on the mold at the speed of 300 r / min and the wire spacing of 1.0 mm;

[0069] S3: end treatment: remove the insulating paint at the end of the coil lead-out wire by mechanical scraping method at the speed of 5 mm / s, expose the metal conductor, which is convenient for subsequent wiring;

[0070] S4: curing and insulation treatment: place the wound coil in modified epoxy impregnating varnish FJ1840, soak for 10 min at 30 ℃, after impregnating, hang the coil vertically, drop varnish for 30 min, let the excess varnish drop, the thickness of the paint layer is 30 μm, then dry at 150 ℃ for 4 h, to enhance the mechanical strength and insulation performance of the coil, and fix the shape of the coil; if it is a multi-layer coil, need to add insulating paper or insulating film between the layers to prevent short circuit between the layers;

[0071] S5: Assembling: embedding the cured coil into the slot of the stator core, completing the assembly of the winding and the core, and preparing the coil.

[0072] Experiment: taking the coils prepared from Examples 1-3 and Comparative Examples 1-2, samples were prepared, and the performance of the samples was tested.

[0073] Heat resistance detection: the high-temperature box furnace was used to test the heat resistance, the sample was placed in the high-temperature box furnace, and the temperature was increased at a rate of 5℃ / min, and the sample was kept for 1h every time the temperature was increased by 100℃. The temperature at which the insulation failure (such as breakdown, short circuit) or structural damage (such as ceramic cracking, coil falling off) occurred was recorded, which was the heat resistance temperature.

[0074] Thermal conductivity detection: the laser flash method was used, the sample was processed into a circular sheet with a diameter of 10mm and a thickness of 2mm, the front surface of the sample was heated by laser pulse in a vacuum environment, and the change curve of the back surface temperature with time was recorded by an infrared detector, and the thermal diffusivity was calculated. Combined with the sample density and specific heat capacity, the thermal conductivity was derived, thermal conductivity = thermal diffusivity x density x specific heat capacity.

[0075] Peeling strength detection: 180° peeling test was used, high-strength adhesive was used to fix the copper coil layer and the clamp of the tensile testing machine, and the copper coil was pulled vertically to the surface of the sample at a rate of 50mm / min. The maximum force value during the peeling process was recorded.

[0076] Table 1: Performance test results of samples

[0077] Heat resistance temperature (°C) Thermal conductivity (W / (m-K)) Peeling strength (N / mm) Example 1 400 150 17 Example 2 390 160 20 Example 3 395 170 18 Comparative Example 1 130 0.3 1.2 Comparative Example 2 120 0.4 1.3

[0078] Conclusion: the heat resistance temperature of the multilayer copper-clad ceramic coil prepared in Examples 1-3 reaches 390-400℃, and the coil can work stably in a high-temperature environment; the thermal conductivity is 150-170W / (m·K), and the coil has strong heat dissipation capacity; the peeling strength reaches 17-20N / mm, the coil is tightly combined with the ceramic substrate, and the mechanical reliability is high.

[0079] Comparative Example 1 used PCB (printed circuit board) printed winding to prepare the coil, and compared with the examples, the heat resistance temperature, thermal conductivity and peeling strength of the coil were significantly reduced; Comparative Example 2 used enameled wire winding to prepare the coil, and compared with the examples, the heat resistance temperature, thermal conductivity and peeling strength of the coil were significantly reduced.

[0080] In summary, the multilayer copper-clad ceramic coil prepared by the application realizes a qualitative leap in temperature resistance, thermal conductivity and mechanical bonding strength compared with traditional PCB coils and enameled wire windings through the use of ceramic substrates, copper coil metallization treatment and vacuum diffusion welding process, perfectly solves the bottleneck of existing schemes in high temperature stability, heat dissipation efficiency and long-term service reliability, and provides key technical support for the application of axial flux motors in high power density scenarios (such as new energy vehicles, aircraft power).

[0081] The products after the final welding of examples 1-3 are subjected to slice SEM analysis to judge the cavities and bonding conditions of the welding interface, and the results are shown in Figure 7 ; as shown in Figure 7 , the copper coil layer and the porcelain chip produce obvious metallurgical bonding, forming an ultra-thin diffusion welding layer, and the interface has no cavity; the welding structure can well guarantee the uniform and rapid heat transfer of the coil, improve the current carrying capacity of the coil, allow the coil to produce a stronger magnetic field, and improve the designability of the coil power design.

[0082] It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A method for preparing a multilayer copper-clad ceramic coil for an axial flux motor, characterized in that: Includes the following steps: S1: Drill holes in ceramic sheet and prepare copper coil: Drill holes in the ceramic sheet (4) where conductive conduction is required to form conductive through holes (1); and make copper coil at the same time. S2: Embedding copper particles in the ceramic plate hole: Embedding copper particles (2) in the conductive through hole (1) of the ceramic plate; S3: Preparation of metallized coil: A titanium metal layer and a nickel metal layer are uniformly plated sequentially on the surface of a copper coil to obtain a metallized coil (3); S4: Stacking: The metallized coil (3) and the ceramic piece (4) embedded with copper particles (2) are stacked alternately to form a multi-layer structure in which the metallized coil (3) and the ceramic piece (4) are interspersed. S5: Vacuum diffusion welding: The multilayer structure is placed in a vacuum diffusion welding furnace and diffusion welding is performed on the multilayer structure using pressure diffusion welding technology to form a welding layer (6) between the copper coil layer (5) and the ceramic sheet (4) to produce a multilayer copper-clad ceramic coil.

2. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 1, characterized in that: In S1, the ceramic tile is one of alumina, silicon nitride, and aluminum nitride.

3. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 1, characterized in that: In S1, the copper coil is manufactured by one of the following methods: laser cutting, etching, or die stamping.

4. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 1, characterized in that: In S2, the height of the copper particles is 0-10 μm smaller than the thickness of the ceramic sheet.

5. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 4, characterized in that: The diameter of the copper particles is 0-30 μm smaller than the diameter of the ceramic pores.

6. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 1, characterized in that: In step S3, a titanium metal layer and a nickel metal layer are plated on the surface of the copper coil using one of the following methods: magnetron sputtering, vapor deposition, spraying, electroplating, or electroless plating.

7. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 6, characterized in that: The thickness of the titanium metal layer is 0.3μm-4μm.

8. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 6, characterized in that: The thickness of the nickel metal layer is 0.1-2 μm.

9. The method for preparing a multilayer copper-clad ceramic coil for an axial flux motor according to claim 1, characterized in that: In S5, the process conditions for pressure diffusion welding are: welding temperature 770-870℃, pressure 4-8MPa, and high-temperature pressure welding time 60-600min.

10. A multilayer copper-clad ceramic coil for an axial flux motor, characterized in that: It is prepared by the preparation method according to any one of claims 1-9.

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