Double-layer coil and method for preparing double-layer coil

Abstract

The embodiment of the invention relates to the technical field of wireless charging, and discloses a double-layer coil and a method for preparing the double-layer coil, the double-layer coil comprises a first coil layer, a second coil layer, a connecting layer and a lead connecting structure, the second coil layer and the first coil layer are in cross connection to form a double-layer cross structure, and the lead connecting structure is connected with the second coil layer. The connecting layer is arranged between the first coil layer and the second coil layer, and the lead connecting structure is electrically connected with the double-layer cross structure. In this way, the influence of the skin effect and the eddy current effect on the coil performance can be effectively reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wireless charging technology, and in particular, to a double-layer coil and a method for preparing the double-layer coil. Background Art

[0002] Wireless charging coils are developing towards high frequency, miniaturization and high efficiency. High frequency applications can reduce coil size and improve transmission efficiency, but it also brings technical challenges such as skin effect and eddy current loss. Wireless charging coils are usually composed of wires, magnetic materials and insulating materials. The wire material is mostly copper wire, which is formed into a coil through a specific winding method. At present, the mainstream preparation solution for wireless charging coils is to adopt a single coil design, or a single coil with an FPC transfer solution. This technical solution can only produce a single-layer coil structure, and its process is relatively simple, but there are obvious technical limitations in high-frequency application scenarios.

[0003] In the process of implementing the embodiments of the present application, the inventors found that: at present, the single-layer coil structure will produce significant eddy current effect under high-frequency working state, which will cause uneven current distribution in the wire, increase AC resistance, and thus reduce charging efficiency and generate more heat loss. This effect is particularly obvious in high-frequency and high-power charging scenarios, which seriously restricts the further development of wireless charging technology. Summary of the invention

[0004] The main technical problem solved by the embodiments of the present application is to provide a double-layer coil, which effectively reduces the influence of skin effect and eddy current effect on the coil performance.

[0005] In order to solve the above technical problems, a technical solution adopted in an embodiment of the present application is: providing a double-layer coil, including a first coil layer, a second coil layer, a connecting layer and a lead connection structure, the second coil layer is cross-connected with the first coil layer to form a double-layer cross structure, the connecting layer is arranged between the first coil layer and the second coil layer, and the lead connection structure is electrically connected to the double-layer cross structure.

[0006] Optionally, the connection layer further includes an inner ring region and an outer ring region sequentially arranged from inside to outside, and the inner ring region and the outer ring region form a magnetic flux path.

[0007] Optionally, the thickness of the connection layer is 0.1-0.5 mm, and the thermal conductivity of the connection layer is not less than 1 W / (m·K).

[0008] Optionally, the first coil layer and the second coil layer are wound in opposite directions, and the lead-out end of the first coil layer is connected to the lead-in end of the second coil layer to form a closed loop structure.

[0009] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present application is: providing a method for preparing a double-layer coil, comprising: providing a first coil layer and a second coil layer; providing a connecting layer having an insulating substrate and a thermally conductive filler; arranging the connecting layer between the first coil layer and the second coil layer and fixedly connecting them to form a double-layer cross structure; providing a circuit board, and electrically connecting the double-layer cross structure to the circuit board to obtain a double-layer coil.

[0010] Optionally, the method further includes: providing a magnetic material layer; arranging the magnetic material layer on one side of the connecting layer; and providing a pressing device to press the magnetic material layer and the connecting layer.

[0011] Optionally, before the step of fixing and connecting the connection layer, the method further includes: pre-treating the connection layer; evenly dispersing the thermal conductive filler in the insulating substrate; and controlling the thickness of the connection layer within the range of 0.1-0.5 mm.

[0012] Optionally, the fixed connection step includes: placing the connection layer on the surface of the first coil layer; applying a predetermined pressure to the connection layer; and maintaining the connection layer at a predetermined temperature for a predetermined time.

[0013] Optionally, after the step of fixing the connection layer, the method further includes: providing a temperature monitoring element; and connecting the temperature monitoring element to a temperature control system.

[0014] Optionally, the electrical connection step includes: determining the lead positions of the first coil layer and the second coil layer; providing welding equipment to connect the leads to the circuit board; and insulating and packaging the welding points.

[0015] An embodiment of the present application provides a double-layer coil, including a first coil layer, a second coil layer, a connecting layer and a lead connecting structure. The second coil layer is cross-connected with the first coil layer to form a double-layer cross structure. The connecting layer is arranged between the first coil layer and the second coil layer. The lead connecting structure is electrically connected to the double-layer cross structure. Through the special double-layer cross structure design, the influence of skin effect and eddy current effect on coil performance is effectively reduced. The connecting layer structure not only provides stable mechanical support, but also optimizes the magnetic flux path through the reasonable arrangement of inner and outer ring areas, which not only ensures the high performance of the product, but also realizes the compactness of the structure, and has good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0017] Figure 1 is a schematic diagram of a double-layer coil according to an embodiment of the present application;

[0018] Figure 2 is a flow chart of preparing a double-layer coil according to an embodiment of the present application;

[0019] Figure 3 is a flowchart of another embodiment of step S103 of the embodiment of the present application;

[0020] Figure 4 is a flowchart of another embodiment of step S103 of the embodiment of the present application;

[0021] Figure 5 is a flowchart of another embodiment of step S104 of the embodiment of the present application;

[0022] Figure 6 is a flow chart of another embodiment of preparing a double-layer coil according to an embodiment of the present application;

[0023] Figure 7 is a flow chart of another embodiment of preparing a double-layer coil in the embodiment of the present application;

[0024] The reference numerals in the specific implementation manner are as follows: 100, double-layer coil; 10, first coil layer; 20, second coil layer; 30, connection layer; 40, lead connection structure. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element or there can be one or more centered elements therebetween. When an element is described as "connected" to another element, it can be directly connected to another element or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "vertical", "horizontal", etc. used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 to the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0026] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0027] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0028] See also Figure 1 The double-layer coil 100 includes a first coil layer 10, a second coil layer 20, a connecting layer 30 and a lead connecting structure 40. The first coil layer 10 and the second coil layer 20 adopt an annular structure. The second coil layer 20 is located above the first coil layer 10. The two are cross-connected to form a double-layer cross structure. This double-layer cross structure can significantly reduce skin effect and eddy current effect.

[0029] The connection layer 30 is arranged between the first coil layer 10 and the second coil layer 20. The connection layer 30 includes an inner ring area and an outer ring area arranged in sequence from the inside to the outside, and the inner ring area is made of a high magnetic permeability material, and the outer ring area is made of a low magnetic permeability material. The inner ring area and the outer ring area are coaxially arranged and connected through a radial transition structure to form a magnetic flux path together. The outer circumference of the inner ring area is tightly fitted with the inner circumference of the outer ring area to ensure the continuity of the magnetic flux path.

[0030] The lead connection structure 40 includes a plurality of lead terminals, which are electrically connected to the lead-out ends of the double-layer cross structure. The lead connection structure 40 is arranged in a symmetrical design to ensure the stability of electrical performance.

[0031] In the embodiment of the present application, the winding directions of the first coil layer 10 and the second coil layer 20 are opposite, the lead-out end of the first coil layer 10 is connected to the lead-in end of the second coil layer 20 to form a closed loop structure, and the alpha winding form is adopted to make the eddy current between the first coil layer 10 and the second coil layer 20 distributed in opposite directions. This design enables the double-layer coil 100 to maintain good electromagnetic performance under high-frequency working conditions.

[0032] In the implementation mode of the present application, efficient operation of the double-layer coil 100 is achieved through reasonable structural design, and the inner and outer ring area design of the connecting layer 30 optimizes the magnetic flux path, improves the working efficiency of the coil, and the overall structure is compact and has good practicality.

[0033] In the embodiment of the present application, the connecting layer 30 is arranged between the first coil layer 10 and the second coil layer 20, and its thickness is strictly controlled in the range of 0.1-0.5 mm. Experimental verification shows that when the thickness of the connecting layer 30 is less than 0.1 mm, its mechanical strength is insufficient and it is easy to deform during the assembly process; when the thickness exceeds 0.5 mm, it will affect the compactness of the coil as a whole and reduce the heat dissipation efficiency.

[0034] The thermal conductivity of the connection layer 30 is controlled to be no less than 1W / (m·K). This parameter index is determined based on a large amount of experimental data analysis, and provides a good heat conduction channel while ensuring insulation performance. When the thermal conductivity reaches this level, the connection layer 30 can effectively conduct the heat generated by the first coil layer 10 and the second coil layer 20 in a timely manner to avoid local overheating.

[0035] The first coil layer 10 and the second coil layer 20 are reliably connected through the connection layer 30. Since the connection layer 30 has a specific thickness and thermal conductivity, the double-layer coil 100 can maintain a stable temperature distribution under high-frequency working conditions. The lead connection structure 40 adopts a distributed layout to ensure uniform distribution of current. By precisely controlling the thickness and thermal conductivity of the connection layer 30, this embodiment achieves excellent heat dissipation performance while ensuring structural stability. This parameter optimization design enables the double-layer coil 100 to have better working stability and reliability, and is particularly suitable for use in scenarios with high requirements for heat dissipation performance.

[0036] In some preferred embodiments, the connection layer 30 is a double-sided adhesive layer.

[0037] In some preferred embodiments, a microchannel heat dissipation network is also provided in the connection layer 30. The microchannel heat dissipation network is distributed in a honeycomb shape, providing a multi-path heat dissipation channel. The microchannel heat dissipation network adopts a partitioned layout, and heat dissipation channels of different densities are respectively arranged in the inner ring area and the outer ring area. The heat dissipation channels in the inner ring area are radially distributed, and the heat dissipation channels in the outer ring area are annularly distributed. The combination of the two distribution methods ensures the uniformity of heat dissipation. The lead connection structure 40 adopts a decentralized layout to avoid local heat concentration. A heat diffusion structure is provided at the lead connection to further enhance the heat conduction ability. The magnetic flux path design of the connection layer 30 cooperates with the heat dissipation channel layout to achieve the optimal heat dissipation effect without affecting the electromagnetic performance. In this embodiment, the heat dissipation performance of the double-layer coil 100 is significantly improved through the organic combination of structural optimization and heat dissipation system. Experimental data show that the temperature rise of the coil using this design is reduced by more than 30% compared with the traditional structure under continuous working conditions, providing a reliable solution for high-frequency and high-power applications.

[0038] The embodiment of the present application provides a double-layer coil 100, including a first coil layer 10, a second coil layer 20, a connecting layer 30 and a lead connecting structure 40. The second coil layer 20 is cross-connected with the first coil layer 10 to form a double-layer cross structure. The connecting layer 30 is arranged between the first coil layer 10 and the second coil layer 20. The lead connecting structure 40 is electrically connected to the double-layer cross structure. Through the special double-layer cross structure design, the influence of skin effect and eddy current effect on coil performance is effectively reduced. The connecting layer 30 structure not only provides stable mechanical support, but also optimizes the magnetic flux path through the reasonable arrangement of inner and outer ring areas, which not only ensures the high performance of the product, but also realizes the compactness of the structure, and has good engineering application value.

[0039] See also Figure 2 The present application also provides a method for preparing a double-layer coil, the method comprising:

[0040] Step S101: providing a first coil layer and a second coil layer;

[0041] Step S102: providing a connection layer having an insulating substrate and a thermally conductive filler;

[0042] Step S103: arranging the connection layer between the first coil layer and the second coil layer and fixedly connecting them to form a double-layer cross structure;

[0043] See also Figure 3 , step S103 further includes:

[0044] Step S131: placing the connection layer on the surface of the first coil layer;

[0045] Step S132: applying a predetermined pressure to the connection layer;

[0046] Step S133: Maintain at a predetermined temperature for a predetermined time.

[0047] First, the prepared connection layer is placed on the surface of the first coil layer. The connection layer is precisely aligned with the coil by a positioning fixture. Then, a predetermined pressure is applied to the connection layer using a pressing device, and the pressure value is controlled within the range of 0.5-1.0MPa.

[0048] The lamination process is carried out at a specific temperature, set at 120-150°C. The temperature and pressure conditions are maintained for a predetermined time, usually 15-30 minutes. This combination of process parameters ensures a solid bond between the connecting layer and the coil while preventing excessive temperature from affecting the performance of the coil.

[0049] In the embodiment of the present application, the reliability of the double-layer coil structure is ensured by precisely controlling the preparation process and the fixing connection process of the connection layer. The optimized design of the process parameters enables the final product to have excellent mechanical strength and heat dissipation performance.

[0050] See also Figure 4 After step S103, the method further includes:

[0051] Step S120: providing a temperature monitoring element;

[0052] Step S130: Connecting the temperature monitoring element to a temperature control system.

[0053] Customized installation tools are used to place temperature sensors at preset detection points. Dedicated lines are designed to connect temperature monitoring components to the temperature control system. Temperature calibration and response time testing are required during system commissioning.

[0054] Step S104: providing a circuit board, and electrically connecting the double-layer cross structure to the circuit board to obtain a double-layer coil.

[0055] See also Figure 5 , step S104 further includes:

[0056] Step S141: determining the lead positions of the first coil layer and the second coil layer;

[0057] Step S142: providing welding equipment to connect the lead wire to the circuit board;

[0058] Step S143: Insulate and package the welding points.

[0059] First, determine the lead positions of the first coil layer and the second coil layer, and fix the leads with fixtures. Use precision welding equipment to reliably connect the leads to the circuit board. Strictly control the temperature and time parameters during the welding process to ensure the quality of the solder joints. Perform comprehensive tests on the assembled products, including electrical performance tests, temperature response tests, and reliability verification. Through test data analysis, confirm that the product performance meets the design requirements. Finally, perform aging tests to verify the long-term reliability of the product.

[0060] The embodiment of the present application provides a method for preparing a double-layer coil, including providing a first coil layer and a second coil layer; providing a connection layer having an insulating substrate and a thermally conductive filler; arranging the connection layer between the first coil layer and the second coil layer and fixedly connecting them to form a double-layer cross structure; providing a circuit board, electrically connecting the double-layer cross structure to the circuit board to obtain a double-layer coil, and through the above preparation process, the connection layer forms a stable structural support between the upper and lower coils. A special pretreatment process and precise parameter control are used to ensure that the thermally conductive filler is evenly distributed in the insulating substrate, which effectively improves the heat dissipation performance. Through the optimized fixed connection process and electrical connection design, the reliability of the structure and the unification of electrical performance are achieved. This preparation method has the characteristics of simple process and strong repeatability, and is suitable for industrial application.

[0061] See also Figure 6 , before step S103, further comprising:

[0062] Step S105: preprocessing the connection layer;

[0063] During the preparation process, the connection layer needs to be pretreated. The pretreatment includes two steps: cleaning and surface activation. Cleaning uses ultrasonic cleaning to remove surface impurities; surface activation uses plasma treatment to improve the bonding performance of the connection layer surface.

[0064] Step S106: evenly dispersing the thermal conductive filler in the insulating substrate;

[0065] After the pretreatment is completed, the thermal conductive filler is evenly dispersed in the insulating substrate. The dispersion process uses a combination of mechanical stirring and ultrasonic dispersion to ensure the uniformity of the thermal conductive filler in the insulating substrate. By controlling the dispersion process parameters, the thermal conductive filler is distributed in a network shape to form a continuous thermal conductive channel.

[0066] Step S107: Control the thickness of the connection layer within the range of 0.1-0.5 mm.

[0067] The thickness of the connecting layer is controlled by a precision coating process to be within the range of 0.1-0.5mm. The coating process uses automated equipment to adjust the coating pressure and speed to ensure the uniformity of the thickness of the connecting layer. After the coating is completed, an online thickness gauge is used for real-time monitoring to ensure that the thickness meets the requirements.

[0068] In the embodiment of the present application, the reliability of the double-layer coil structure can be ensured by pre-treating the connecting layer, then evenly dispersing the thermal conductive filler in the insulating substrate, and finally controlling the thickness of the connecting layer within the range of 0.1-0.5 mm.

[0069] See also Figure 7, the method further comprises:

[0070] Step S108: providing a magnetic material layer;

[0071] The magnetic material is surface treated and surface impurities are removed by chemical cleaning. The magnetic material layer is then cut into the required size by precision segmentation equipment and its magnetic properties are tested.

[0072] Step S109: disposing the magnetic material layer on one side of the connecting layer;

[0073] The magnetic material layer is placed at the designated position of the connection layer and pressed with a special pressing device. The process parameters of the pressing process are strictly controlled: the pressing pressure is 1.0-1.5MPa, the pressing temperature is maintained at 140-160℃, and the pressing time is controlled within the range of 20-30 minutes. A vacuum auxiliary system is used during the pressing process to avoid bubbles between layers.

[0074] Step S110: providing a laminating device to laminate the magnetic material layer and the connecting layer.

[0075] After the pressing is completed, the overall structure is electrically connected to the circuit board. Customized fixtures are used during the connection process to ensure the relative position of each layer of the structure is accurate. The performance of the assembled product is verified by online testing equipment to ensure that its working characteristics meet the design requirements.

[0076] In an embodiment of the present application, a magnetic material layer is provided, and then the magnetic material layer is arranged on one side of the connecting layer. Finally, a pressing device is provided to press the magnetic material layer and the connecting layer, thereby achieving high-quality integration of a double-layer coil structure.

[0077] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A double-layer coil, characterized in that: include: First coil layer; a second coil layer, the second coil layer is cross-connected with the first coil layer to form a double-layer cross structure; A connecting layer, disposed between the first coil layer and the second coil layer; A lead connection structure is electrically connected to the double-layer cross structure.

2. The double-layer coil according to claim 1, characterized in that: The connection layer further includes an inner ring region and an outer ring region which are sequentially arranged from the inside to the outside, and the inner ring region and the outer ring region form a magnetic flux path.

3. The double-layer coil according to claim 1, characterized in that: The thickness of the connection layer is 0.1-0.5 mm, and the thermal conductivity of the connection layer is not less than 1 W / (m·K).

4. The double-layer coil according to claim 1, characterized in that: The winding directions of the first coil layer and the second coil layer are opposite, and the lead-out end of the first coil layer is connected to the lead-in end of the second coil layer to form a closed loop structure.

5. A method for preparing a double-layer coil, characterized in that: include: providing a first coil layer and a second coil layer; providing a connecting layer having an insulating substrate and a thermally conductive filler; The connection layer is arranged between the first coil layer and the second coil layer and fixedly connected to form a double-layer cross structure; A circuit board is provided, and the double-layer cross structure is electrically connected to the circuit board to obtain a double-layer coil.

6. The method according to claim 5, characterized in that The method further comprises: providing a magnetic material layer; Disposing the magnetic material layer on one side of the connecting layer; A pressing device is provided to press the magnetic material layer and the connecting layer.

7. The method according to claim 5, characterized in that Before the step of fixing the connection layer, the method further comprises: Preprocessing the connection layer; Dispersing the thermally conductive filler evenly in the insulating substrate; The thickness of the connecting layer is controlled within the range of 0.1-0.5 mm.

8. The method according to claim 5, characterized in that The fixed connection step comprises: placing the connection layer on the surface of the first coil layer; applying a predetermined pressure to the connecting layer; Maintain at a predetermined temperature for a predetermined time.

9. The method according to claim 5, characterized in that After the step of fixing the connection layer, the method further comprises: Provide temperature monitoring components; The temperature monitoring element is connected to a temperature control system.

10. The method according to claim 5, characterized in that The electrical connection step comprises: Determine the lead positions of the first coil layer and the second coil layer; Providing welding equipment to connect the lead to the circuit board; Insulate and encapsulate the welds.

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