Planar coil based on winding-cutting and preparation method and application thereof

Abstract

The invention discloses a winding-cutting-based planar coil and a preparation method and application thereof, and belongs to the technical field of preparation of planar coils, one side, without conductive adhesive, of a copper foil is uniformly coated with a layer of ferrite core coating in a blade coating mode, drying is conducted at the room temperature, and the copper foil subjected to insulation treatment is obtained; the nickel-zinc ferrite magnetic core rod is adhered to one side, with the conductive adhesive, of the insulated copper foil, and the magnetic core rod adhered with the copper foil is placed on a rolling support to be rolled; the planar coil based on winding-cutting is obtained by cutting the rolled copper foil and polishing the end face, and the induced voltage intensity of the planar coil is effectively improved by introducing a ferrite rod (nickel-zinc ferrite rod) and a ferroferric oxide coating as a composite magnetic core of the planar coil. By adjusting the thickness of the copper foil, the number of winding layers, the insulating material and the cutting mode, the size, the inductance value and the electromagnetic property of the coil can be flexibly controlled, and different application requirements are met.

Description

Technical Field

[0001] This invention belongs to the field of planar coil fabrication technology, specifically relating to a planar coil based on winding-cutting, its fabrication method, and its application. Background Technology

[0002] As a core component in fields such as wireless charging, radio frequency communication, and power electronics, planar coils directly determine the energy transmission efficiency, signal stability, and power density of terminal devices. Therefore, the manufacturing process has been continuously iterated around the three major goals of performance improvement, cost reduction, and efficiency optimization.

[0003] PCB etching has long been the mainstream method for fabricating planar coils, removing excess copper foil to form coil patterns. However, this technology suffers from problems such as material utilization of less than 50%, high waste liquid treatment costs, and the need for repeated lamination / etching of multi-layer coils. Enamelled wire winding relies on manual or mechanical winding of enamelled wire into a planar structure, suitable for small-batch customized needs. However, this process has two major drawbacks: firstly, low production efficiency, producing only a single coil per batch, unable to meet the needs of large-scale production; secondly, poor consistency, with fluctuations in coil spacing and wire tension during winding leading to large deviations in coil inductance. Inkjet printing, as a new additive method, forms coils by spraying conductive ink point by point. Its advantage lies in flexible pattern design, but limited by the properties of the conductive ink, the coil resistance is relatively high, failing to meet the requirements of high-power applications; simultaneously, the equipment and ink costs are high, and multiple printing layers are required to increase conductor thickness, resulting in low production efficiency and difficulty in achieving industrial application.

[0004] From planar coil accelerometers in the aerospace field to superconducting coil arrays in nuclear fusion, the performance requirements for planar coils in various application scenarios continue to upgrade, and the technical bottlenecks of traditional processes are becoming increasingly prominent, urgently requiring innovative preparation paths to break through existing limitations. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a planar coil based on winding and cutting.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including, A layer of ferrite core coating is uniformly coated on the side of the copper foil without conductive adhesive and dried at room temperature to obtain an insulating copper foil. The nickel-zinc ferrite core rod is bonded to the conductive adhesive side of the insulated copper foil. The core rod with the bonded copper foil is placed on the rolling bracket and rolled. After the copper foil is rolled, it is cut and the end face is polished to obtain a planar coil based on winding and cutting.

[0009] In a preferred embodiment of the method for preparing a planar coil based on winding-cutting according to the present invention, the ferrite core coating is prepared by adding Fe3O4 nanoparticles and polyvinylpyrrolidone to a mixed solvent of ethanol and deionized water.

[0010] In a preferred embodiment of the method for preparing a planar coil based on winding and cutting according to the present invention, the Fe3O4 nanoparticles have a particle size of 48-52 nm.

[0011] In a preferred embodiment of the method for preparing a planar coil based on winding and cutting according to the present invention, the concentration of Fe3O4 nanoparticles in the ferrite core coating is 18-20wt%.

[0012] In a preferred embodiment of the method for preparing a planar coil based on winding and cutting according to the present invention, the concentration of polyvinylpyrrolidone in the ferrite core coating is 4.8-5.0 wt%.

[0013] In a preferred embodiment of the method for preparing a planar coil based on winding-cutting according to the present invention, the volume ratio of ethanol to deionized water in the ferrite core coating is 3:7.

[0014] In a preferred embodiment of the method for preparing a planar coil based on winding and cutting according to the present invention, the coating thickness of the ferrite core coating is 2-3 μm.

[0015] In a preferred embodiment of the method for preparing a planar coil based on winding and cutting according to the present invention, the permeability of the nickel-zinc ferrite core rod is 650.

[0016] Another objective of this invention is to overcome the shortcomings of the prior art and provide a planar coil based on winding and cutting and its application as a core component in the fields of wireless charging, radio frequency communication, and power electronics.

[0017] Beneficial effects of this invention: (1) In this invention, a ferrite rod (nickel-zinc ferrite rod) and iron oxide coating are used as a composite magnetic core of a planar coil. The ferrite rod serves as the main magnetic path, effectively concentrating the magnetic lines of force, while the iron oxide coating can fill the air gap and form an auxiliary magnetic path, effectively improving the induced voltage intensity of the planar coil.

[0018] (2) The present invention uses integral copper foil as conductor material, which effectively reduces the resistance of planar coil and has good stability. It can adapt to high current and high power applications. The resulting planar coil has excellent conductivity, low resistance and strong current carrying capacity.

[0019] (3) Since the planar coil prepared by this method is made by winding copper foil with copper rod and cutting, the consistency of the coils in the same batch is guaranteed to a certain extent. The "winding-cutting" method has simple process steps and high repeatability, and can continuously and efficiently realize the preparation of planar coils, significantly improving production efficiency and reducing manufacturing costs.

[0020] (3) By adjusting the copper foil thickness, number of winding layers, insulation material and cutting method, the size, inductance and electromagnetic characteristics of the coil can be flexibly controlled to meet different application requirements. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a flowchart of the preparation method of the present invention.

[0022] Figure 2 This is a schematic diagram of the winding support structure used in the coil winding of the present invention.

[0023] Figure 3 This is a diagram showing the coil winding effect of the present invention.

[0024] Figure 4 This is a physical image of the planar coil obtained in Embodiment 1 of the present invention.

[0025] Figure 5 This is a schematic diagram of the testing system used in this invention.

[0026] Figure 6 This is a comparison diagram of the electromagnetic strength of the planar coils prepared in Embodiment 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0030] Unless otherwise specified, all raw materials used in this invention are commercially available in the field.

[0031] Example 1 Reference Figure 1 This embodiment provides a method for fabricating a planar coil based on winding and cutting, specifically: 1) Preparation of ferrite core coating; Fe3O4 nanoparticles with a particle size of 50 nm and polyvinylpyrrolidone (PVP) were added to a mixed solvent of ethanol and deionized water in a volume ratio of 3:7 to obtain a ferrite magnetic core coating with a Fe3O4 nanoparticle concentration of 20 wt% and a polyvinylpyrrolidone concentration of 5 wt%. 2) Copper foil insulation treatment: A ferrite core coating with a thickness of 2.5 μm is uniformly coated on the side of the copper foil without conductive adhesive and dried at room temperature to obtain an insulating copper foil. 3) Coil winding: A nickel-zinc ferrite core rod with a relative permeability of 650 is bonded to one side of an insulating copper foil with conductive adhesive (to serve as the lead of a planar coil). The core rod with the bonded copper foil is then placed in a position such as... Figure 2 The copper foil is placed on the winding stand shown, and then passed through a narrow gap on the bottom of the stand (to ensure that the copper foil does not shift during the winding process). The motor is then connected to the copper rod via a coupling. The motor is started, and the copper foil is wound onto the copper rod at a low speed. (The winding process...) Figure 3 a) and rolling effect ( Figure 3 b and Figure 3 c) such as Figure 3 .

[0032] 4) Coil cutting: Using a wire cutting device, the sample prepared in step 3) is cut into thin slices with a thickness of 3 mm and a diameter of 10 mm.

[0033] 5) Grinding the coil end face: By sanding the coil end face with sandpaper (to remove the interlayer adhesion and prevent short circuits between layers), the planar coil based on winding-cutting in this embodiment is obtained.

[0034] Figure 4 This is a physical image of the planar coil produced in this embodiment. The brown color on the end face is the ferrite core coating.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that step 1 is omitted. A layer of acrylic insulating varnish with a thickness of 2.5 μm is directly and evenly coated on the side of the copper foil without conductive adhesive and dried at room temperature.

[0036] The remaining steps and processes are the same as in Example 1, resulting in the planar coil of this comparative example.

[0037] Comparing the performance of the planar coils prepared in Example 1 and Comparative Example 1, by... Figure 5 The system shown was subjected to performance testing. The coil performance testing method is as follows: 1. Input a 0-1A, 1kHz AC current with a step size of 0.1A into the Helmholtz coil through a precision current source.

[0038] 2. After filtering the coil output signal, input it into an oscilloscope for measurement. The results are as follows: Figure 6 And as shown in Table 1.

[0039] Table 1

[0040] It can be seen that the coils in both the embodiment and the comparative example exhibit a good linear relationship between induced voltage and magnetic field strength. However, under the same magnetic field strength, the coil in the embodiment can generate a higher induced voltage, demonstrating superior electromagnetic performance.

[0041] Comparative Example 1 The difference between this comparative example and Example 1 is that the concentration of Fe3O4 nanoparticles was adjusted to 25wt%, while the remaining steps and processes were the same as in Example 1. The ferrite core coating of this comparative example was obtained, but the coating agglomerated severely and could not be used for subsequent applications.

[0042] Comparative Example 2 The difference between this comparative example and Example 1 is that the concentration of PVP was adjusted to 7%, while the remaining steps and processes were the same as in Example 1. The resulting ferrite core coating was found to have excessive viscosity, which prevented the formation of a uniform liquid film during coating and reduced the coating's coatability. In addition, excessively high PVP levels also reduced the filling density of the core particles.

[0043] In summary, this invention discloses a planar coil based on winding-cutting, its preparation method, and its application. It proposes a novel process of winding-cutting + composite magnetic core to achieve the synergistic preparation of planar coils with large scale, low resistance, and high magnetic properties.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for fabricating a planar coil based on winding and cutting, characterized in that: include, A layer of ferrite core coating is uniformly coated on the side of the copper foil without conductive adhesive and dried at room temperature to obtain an insulating copper foil. The nickel-zinc ferrite core rod is bonded to the conductive adhesive side of the insulated copper foil. The core rod with the bonded copper foil is placed on the rolling bracket and rolled. After the copper foil is rolled, it is cut and the end face is polished to obtain a planar coil based on winding and cutting.

2. The method for preparing a planar coil based on winding and cutting as described in claim 1, characterized in that: The ferrite core coating is prepared by adding Fe3O4 nanoparticles and polyvinylpyrrolidone to a mixed solvent of ethanol and deionized water.

3. The method for preparing a planar coil based on winding and cutting as described in claim 2, characterized in that: The Fe3O4 nanoparticles have a particle size of 48-52 nm.

4. The method for preparing a planar coil based on winding and cutting as described in claim 2, characterized in that: The concentration of Fe3O4 nanoparticles in the ferrite core coating is 18-20 wt%.

5. The method for preparing a planar coil based on winding and cutting as described in claim 4, characterized in that: The concentration of polyvinylpyrrolidone in the ferrite core coating is 4.8-5.0 wt%.

6. The method for preparing a planar coil based on winding and cutting as described in claim 5, characterized in that: The volume ratio of ethanol to deionized water in the ferrite core coating is 3:

7.

7. The method for preparing a planar coil based on winding and cutting as described in claim 6, characterized in that: The coating thickness of the ferrite core coating is 2-3 μm.

8. The method for preparing a planar coil based on winding and cutting as described in claim 6, characterized in that: The permeability of the nickel-zinc ferrite core rod is 650.

9. A planar coil prepared by any one of the preparation methods described in claims 1 to 8.

10. The application of the planar coil as described in claim 9 as a core component in the fields of wireless charging, radio frequency communication, and power electronics.

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