A wireless transmission coil assembly

Abstract

The utility model discloses a wireless transmission coil assembly, including substrate and coil group, the substrate has first end face and second end face, and first end face and second end face set up mutually away from each other, be equipped with the electrically conductive portion on the substrate, the coil group includes first coil and second coil, and first coil sets up in first end face, and second coil sets up in second end face, two ends of first coil are equipped with first connecting end and first wiring end respectively, and two ends of second coil are equipped with second connecting end and second wiring end respectively, and first connecting end and second connecting end all are electrically connected with electrically conductive portion electrically, to make first coil and second coil electrically conductive, first wiring end and second wiring end all are by the circumference of substrate and stretch out, the utility model discloses the substrate and coil group with a whole with magnetic sheet main part are assembled, and the first wiring end and second wiring end of coil group are located the circumference of substrate, and it is convenient to connect into the coil group with electric equipment or external power supply.

Description

Technical Field

[0001] This utility model relates to the field of wireless charging technology, and in particular to a wireless transmission coil assembly. Background Technology

[0002] In a wireless charging system, the transmitting coil, as the core component, generates an alternating magnetic field by applying an alternating current, which induces an electromotive force in the receiving coil, thereby achieving contactless power transfer. Traditional coil manufacturing typically involves tightly winding multiple turns of wire radially on the plane of a ferrite magnetic sheet. After winding, the terminals at both ends of the coil are located on the inner and outer sides of the magnetic sheet, respectively.

[0003] However, this process requires precise control of the number of turns and spacing to ensure coil performance. Furthermore, after winding, additional fixing measures are needed to secure the coil position, further increasing the assembly steps and difficulty. In addition, the radial distribution of the terminals necessitates wiring the inner terminals across the radius of the magnetic sheet, increasing wiring complexity and coil thickness.

[0004] Related technologies typically involve creating lead slots on the magnetic sheet to bring out the terminals inside. However, slotting disrupts the overall stress structure, easily leading to stress concentration at the slotted area and reducing the sheet's mechanical strength and magnetic properties. Slotting also affects the integrity of the magnetic circuit and creates an air gap effect, increasing magnetic reluctance. Furthermore, there is significant leakage flux at the slotted area. According to the law of electromagnetic induction, a changing magnetic field passing through a conductive material induces a circular induced current (eddy current) within the material. Since the aluminum-plastic film (outer aluminum foil) and electrodes (copper / aluminum metal) of the pouch battery in a wireless charging system are conductive, leakage flux passing through these components generates significant eddy current losses, potentially causing localized battery temperatures to exceed limits, posing a risk of explosion and fire. Regarding winding, the geometry of the slot interferes with the uniformity of the wire arrangement, enhancing skin and proximity effects and increasing copper losses. In terms of structural strength, slotting disrupts the overall stress structure, and the inner edge of the slotted area experiences significant shear force, greatly increasing the likelihood of product damage in drop tests. Utility Model Content

[0005] In order to overcome at least one of the defects of the prior art, the present invention provides a wireless transmission coil assembly, which assembles the assembled substrate and coil assembly as a whole with the magnetic sheet body, thus avoiding the problem of complicated assembly steps; and the first and second terminals of the coil assembly are located on the outer periphery of the substrate, which facilitates the connection of the coil assembly to electrical equipment or external power supply, thus avoiding the need to cut slots on the magnetic sheet.

[0006] The technical solution adopted by this utility model to solve its problem is:

[0007] A wireless transmission coil assembly, comprising,

[0008] A substrate having a first end face and a second end face, the first end face and the second end face being disposed opposite to each other; the substrate having an electrically conductive portion.

[0009] The coil assembly includes a first coil and a second coil. The first coil is disposed on the first end face, and the second coil is disposed on the second end face. The first coil has a first connecting end and a first wiring end at both ends, and the second coil has a second connecting end and a second wiring end at both ends. The first connecting end and the second connecting end are electrically connected to the electrically conductive part so that the first coil and the second coil are electrically connected. The first wiring end and the second wiring end both extend from the outer periphery of the substrate.

[0010] As an optional implementation, the electrically conductive part includes a plurality of through holes, which extend from the first end face to the second end face; a conductive element is provided in the through hole, and the two ends of the conductive element are electrically connected to the first connection end and the second connection end, respectively.

[0011] As an optional implementation, the conductive element includes a conductive post embedded in the through hole, and the conductive post is made of copper or graphene copper.

[0012] As an alternative implementation, the conductive element includes a conductive layer made of copper or graphene copper, which is deposited in the via by physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes.

[0013] As an optional implementation, a plurality of first coil segments are further provided between the first connecting end and the first wiring end, and the plurality of first coil segments are wound around the axis of the substrate; a plurality of second coil segments are further provided between the second connecting end and the second wiring end, and the plurality of second coil segments are wound around the axis of the substrate; the plurality of first coil segments and the plurality of second coil segments are arranged radially along the substrate.

[0014] As an alternative implementation, both the first coil and the second coil are made of copper foil and formed on the substrate using a direct printing molding process.

[0015] As an alternative implementation, both the first coil and the second coil are made of graphene copper and are formed on the substrate using a direct printing process.

[0016] As an optional implementation, the thickness of the substrate is H1, and the value of H1 ranges from 0.08mm to 0.12mm; the cross-sections of the first coil segment and the second coil segment are both rectangular, the thickness of the rectangle is H2, and the value of H2 ranges from 0.15mm to 0.3mm; the width of the rectangle is L, and the value of L ranges from 2.15mm to 2.45mm.

[0017] As an optional implementation, when both the first coil and the second coil are made of copper foil, H1=0.1mm, H2=0.28mm, and L=2.27mm; when both the first coil and the second coil are made of graphene copper, H1=0.1mm, H2=0.175mm, and L=2.27mm.

[0018] As an optional implementation, the first coil segment has N turns and the second coil segment has M turns, where N+M≥11.

[0019] As an alternative implementation, N=M, and N+M=11.

[0020] As an optional implementation, it also includes a magnetic sheet body, on which the substrate and the coil assembly are mounted, and the first terminal and the second terminal both extend from the outer periphery of the magnetic sheet body.

[0021] In summary, the present invention provides the following technical effects:

[0022] 1. This application simplifies the assembly process by directly mounting two coils on the two end faces of the substrate and then assembling the substrate and the coils as a whole with the magnetic sheet body, avoiding the complex winding process and subsequent fixing difficulties. Simultaneously, the first and second terminals extend from the outer periphery of the substrate, eliminating the need for complex operations inside the component when connecting the coil assembly to external circuits. Wiring can be completed quickly and accurately directly through the outer terminals, reducing wiring difficulty and error rate.

[0023] 2. Because the substrate and its coil are assembled with the magnetic sheet body as a whole, both terminals of the coil are located on the outside of the magnetic sheet body, avoiding the problem of slotting the magnetic sheet to bring out the coil terminals. Since the wireless transmission coil assembly of this application does not have slotted magnetic sheets, the wire arrangement is not affected by the slots, maintaining good uniformity. Skin and proximity effects are effectively controlled, reducing copper losses and improving the coil's energy utilization efficiency, thereby enhancing the overall performance of the wireless charging coil assembly. Because the magnetic sheet is not slotted, leakage flux is greatly reduced, thus significantly reducing eddy current losses generated on the aluminum-plastic film and electrodes of the soft-pack battery in the wireless charging system during charging. Battery temperature rise is controlled within a normal range, improving reliability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the assembly structure of the substrate and coil assembly according to an embodiment of the present invention;

[0026] Figure 2 This is a partial axial cross-sectional view of the substrate and coil assembly according to an embodiment of the present invention.

[0027] The meanings of the reference numerals in the attached figures are as follows:

[0028] 10. Substrate; 11. Electrically conductive part; 12. Through hole; 13. Conductive component; 20. First coil; 21. First connection terminal; 22. First wiring terminal; 23. First coil segment; 30. Second coil; 31. Second wiring terminal. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0031] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0032] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0033] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0034] The technical solution of this utility model will be further described below with reference to the embodiments and accompanying drawings.

[0035] See Figure 1 and Figure 2 This utility model discloses a wireless transmission coil assembly, which includes a substrate 10 and a coil group. Specifically, the substrate 10 has a first end face and a second end face, which are disposed opposite to each other, and the substrate 10 is provided with an electrical conduction portion 11. The coil group includes a first coil 20 and a second coil 30, wherein the first coil 20 is disposed on the first end face, and the second coil 30 is disposed on the second end face. (See again) Figure 1The first coil 20 has a first connecting end 21 and a first wiring end 22 at its two ends, and the second coil 30 has a second connecting end and a second wiring end 31 at its two ends. The first connecting end 21 and the second connecting end are both electrically connected to the electrically conductive part 11 so that the first coil 20 and the second coil 30 are electrically connected. The first wiring end 22 and the second wiring end 31 both extend from the outer periphery of the substrate 10.

[0036] Based on this structure, when using the wireless transmission coil assembly of this utility model, the first coil 20 and the second coil 30 can be respectively disposed on the first end face and the second end face of the substrate 10, and the first connection end 21 of the first coil 20 and the second connection end of the second coil 30 can be electrically connected through the electrical conduction part 11 on the substrate 10 to realize the electrical conduction of the two coils.

[0037] Then, the substrate 10 and its coil assembly can be assembled as a whole with the magnetic sheet body. Specifically, an adhesive layer can be provided on the plane of the magnetic sheet body, and then the substrate 10 and its coil assembly can be bonded to the magnetic sheet body through the adhesive layer. Alternatively, a receiving groove can be provided on the magnetic sheet body, and the substrate 10 and its coil assembly can be installed as a whole into the receiving groove, and the first terminal 22 and the second terminal 31 can be connected to the external circuit.

[0038] When connecting the assembled wireless transmission coil assembly to the circuit, the power supply of the transmitter can be connected to the first terminal 22 and the second terminal 31 of the wireless transmission coil assembly, so that the power supply of the transmitter inputs alternating current to the coil assembly. After the first coil 20 is connected to the alternating current, an alternating magnetic field is generated around it. Since the first coil 20 and the second coil 30 are electrically connected through the conductive part 11, the second coil 30 will also have alternating current flowing through it, thereby generating an alternating magnetic field around the second coil 30 as well.

[0039] When the receiving coil is brought close to the wireless transmission coil assembly, the receiving coil will sense an alternating magnetic field, which will then induce an electromotive force in the receiving coil, realizing contactless power transmission and completing the wireless charging process.

[0040] It should be noted that in related technologies, the coil is manufactured by winding a single layer of wire along the radial direction of the magnetic sheet body around its axis. Precise control of the number of turns and spacing is required during winding to ensure coil performance. Furthermore, additional fixing measures are needed after winding, increasing assembly steps and complexity. Additionally, the terminals at both ends of the coil are located radially at both ends of the coil. Wiring requires crossing the magnetic sheet or creating lead grooves on the magnetic sheet to connect the inner terminals of the coil to the external circuitry.

[0041] This application uses two coils, directly mounted on the two end faces of the substrate 10, and electrically connected via the conductive portion 11 on the substrate 10. This allows the first terminal 22 and the second terminal 31 to extend from the outer periphery of the substrate 10. The assembled substrate 10 and its coils are then assembled as a whole with the magnetic sheet body, avoiding the complex winding process and subsequent fixing difficulties, thus simplifying the assembly process.

[0042] In this design, the first terminal 22 and the second terminal 31 extend from the outer periphery of the substrate 10. When connecting the coil assembly to an external circuit, there is no need for complex operations inside the component; wiring can be completed quickly and accurately directly through the outer terminals, reducing wiring difficulty and error rate. Furthermore, this design makes the wiring process more standardized, reduces line damage caused by improper wiring, ensures the stability and reliability of the electrical connection, and improves the overall performance and lifespan of the wireless transmission coil assembly.

[0043] Furthermore, the magnetic sheet body has excellent magnetic conductivity, which can guide the magnetic field generated by the coil assembly to propagate more concentratedly and effectively. After the substrate 10 and the coil assembly thereon are assembled with the magnetic sheet body, the first terminal 22 and the second terminal 31 still extend out of the outer periphery of the magnetic sheet body. Therefore, there is no need to cut grooves on the magnetic sheet. This ensures the integrity of the magnetic sheet structure, maintains the integrity of the overall stress structure, improves stability, and reduces the risk of damage due to drops and impacts during transportation and use.

[0044] Meanwhile, since there are no slots in the magnetic sheet, the wire arrangement is unaffected by the slots, maintaining good uniformity. Skin and proximity effects are effectively controlled, reducing copper losses and improving the coil's energy utilization efficiency, thus enhancing the overall performance of the wireless charging coil assembly. Furthermore, the absence of slots in the magnetic sheet significantly reduces leakage flux, thereby greatly reducing eddy current losses on the aluminum-plastic film and electrodes of the pouch battery during charging. Battery temperature rise is kept within normal range, improving reliability.

[0045] Furthermore, the electrically conductive part 11 includes a plurality of through holes 12, and the through holes 12 extend from the first end face to the second end face. A conductive element 13 is provided within each through hole 12, and both ends of the conductive element 13 are electrically connected to the first connecting end 21 and the second connecting end, respectively.

[0046] Based on this structure, when fabricating the wireless transmission coil assembly, a substrate 10 with a first end face and a second end face is first processed. Several through holes 12 extending from the first end face to the second end face can be formed on the substrate 10. Then, the first coil 20 and the second coil 30 are respectively fixed to the first end face and the second end face of the substrate 10, ensuring that the first connecting end 21 of the first coil 20 and the second connecting end of the second coil 30 are respectively located close to the through holes 12. Subsequently, a conductive element 13 is embedded in the through holes 12. Through welding, pressing, or other methods, one end of the conductive element 13 is tightly electrically connected to the first connecting end 21, and the other end is reliably connected to the second connecting end, thereby achieving electrical conductivity between the first coil 20 and the second coil 30.

[0047] It should be noted that the substrate 10 can be a ceramic substrate, phenolic paper laminate, or other materials in the prior art. It provides an mounting or forming plane for the first coil 20 and the second coil 30, and serves to support the coil assembly.

[0048] Therefore, by setting a through hole 12 on the substrate 10 and embedding a conductive element 13, the connection between the first coil 20 and the second coil 30 is changed from complex wiring on the end face to a straight connection in the vertical direction. This reduces the complexity of the wiring layout, lowers the assembly difficulty, shortens the assembly time, and significantly improves the production efficiency of the entire component.

[0049] Furthermore, the vertically connected structure reduces the risk of poor contact caused by wire bending or squeezing. Even when affected by external factors such as vibration or impact, the connection between the conductive component 13 and the connection end remains stable, ensuring that the current can be transmitted stably during long-term use of the coil assembly, maintaining the efficient and stable operation of the wireless charging process, and greatly improving the reliability and service life of the component.

[0050] In some embodiments, the conductive element 13 includes a conductive post, and the conductive post is embedded in the through hole 12, wherein the conductive post is made of copper or graphene copper.

[0051] Specifically, the conductive post can be tightly fitted to the through hole 12 to prevent loosening or gaps that could affect conductivity. Copper, with its excellent conductivity and ductility, serves as the material for the conductive post, ensuring smooth current conduction between the first coil 20 and the second coil 30, reducing power loss. Graphene-copper combines the superior electrical properties of graphene with the processing characteristics of copper, further enhancing conductivity and reducing resistance.

[0052] Therefore, by embedding the conductive post in the through hole 12, the connection between the conductive post and the connection end is more stable, reducing contact resistance. Even in complex working environments, such as high temperature and high humidity, a stable electrical connection can be maintained, ensuring the long-term stable operation of the coil assembly and avoiding charging interruption or efficiency reduction due to connection problems.

[0053] In other embodiments, the conductive element 13 includes a conductive layer, and the conductive layer is made of copper or graphene copper. The conductive layer is deposited within the via 12 using a physical vapor deposition (PVD) or chemical vapor deposition (CVD) process.

[0054] Based on this structure, when fabricating the wireless transmission coil assembly, a through hole 12 is first opened on the substrate 10, penetrating the first end face and the second end face. To enhance the bonding force between the conductive layer and the inner wall of the through hole 12, the inner wall of the through hole 12 can be pretreated by sandblasting, chemical etching, etc., to form a certain roughness on the inner wall surface.

[0055] If physical vapor deposition (PVD) is used, copper or graphene copper is used as the target material. The substrate 10 is placed in a vacuum chamber, and the target atoms or molecules are desorbed from the target surface under the bombardment of high-energy particles by magnetron sputtering technology, and a conductive layer is deposited on the inner wall of the through hole 12.

[0056] If chemical vapor deposition (CVD) is used, a copper-containing organometallic compound or a mixed gas containing a graphene precursor is used as the raw material. The substrate 10 is placed in the reaction chamber. Under high temperature, the raw material gas undergoes a chemical reaction on the inner wall of the through hole 12, decomposes and deposits to form a conductive layer.

[0057] The conductive layer may also form connecting segments extending to the first end face and the second end face at both ends of the through hole 12. The connecting segments are used to connect with the first connecting end 21 and the second connecting end.

[0058] Therefore, the conductive layer deposited by PVD or CVD processes can form a continuous and dense conductive structure within the via 12, reducing resistance loss during current transmission. The close contact between the conductive layer and the first and second connection terminals reduces contact resistance, ensuring stable current transmission even when high-frequency alternating current passes through. This effectively prevents charging efficiency degradation or device malfunction due to poor connection, guaranteeing efficient and stable operation of the wireless charging process.

[0059] Furthermore, a plurality of first coil segments 23 are provided between the first connecting end 21 and the first wiring end 22, and the plurality of first coil segments 23 are wound around the axis of the substrate 10. A plurality of second coil segments are provided between the second connecting end and the second wiring end 31, and the plurality of second coil segments are wound around the axis of the substrate 10. The plurality of first coil segments 23 and the plurality of second coil segments are all arranged radially along the substrate 10.

[0060] Based on this structure, when an external power source inputs alternating current to the wireless transmission coil assembly, the current flows in from the first terminal 22, passes through multiple first coil segments 23 wound along the axis of the substrate 10 and arranged radially, then connects to the electrical conduction part 11 of the substrate 10 via the first connection terminal 21, and is then conducted through the electrical conduction part 11 to the second connection terminal, then flows through multiple second coil segments, and finally flows out from the second terminal 31.

[0061] During this process, since multiple first coil segments 23 and second coil segments are wound around the axis of the substrate 10, each coil segment generates a ring-shaped alternating magnetic field when alternating current passes through. These ring-shaped magnetic fields superimpose each other, forming a stronger and more uniformly distributed alternating magnetic field around the substrate 10.

[0062] When the receiving coil is brought close to the wireless transmission coil assembly, the receiving coil is in this enhanced and uniform alternating magnetic field, which enables it to induce an electromotive force more efficiently, thereby achieving stable and efficient transmission of electrical energy from the transmitter to the receiver.

[0063] Therefore, multiple first coil segments 23 and second coil segments are arranged radially along the substrate 10, making the generated magnetic field more uniformly distributed in the space around the substrate 10. The uniform magnetic field distribution ensures that the receiving coil can obtain a relatively stable induced electromotive force at different positions, avoiding fluctuations in charging efficiency caused by differences in magnetic field strength, improving the stability and reliability of wireless charging, expanding the effective charging area, and allowing the receiving device to maintain good charging performance even when moving within a certain range.

[0064] Furthermore, compared to traditional single-layer wound coils, this multi-segment winding structure, with layers distributed at both ends of the substrate 10, disperses the stress on the coil. When subjected to external forces, the coil segments can buffer each other, reducing the risk of coil damage due to excessive local stress, improving the overall structural strength and durability of the wireless transmission coil assembly, and extending the product's lifespan.

[0065] In some embodiments, both the first coil 20 and the second coil 30 are made of copper foil and formed on the substrate 10 using a direct printing process.

[0066] In this case, the substrate 10 can be made of phenolic paper-based copper clad laminate, epoxy glass cloth-based copper clad laminate, etc., which are already covered with copper foil. When making the coil using the direct printing process, there is no need to additionally bond the copper foil to the board. When making the coil, the copper foil already on the substrate 10 is used as the raw material, and the direct printing process such as photolithography and etching is used.

[0067] In the photolithography process, photoresist is first coated onto the surface of the copper foil. Then, using a photomask, the designed coil pattern is transferred onto the photoresist through exposure and development steps. Next, an etching process is used to remove the copper foil portions not protected by the photoresist, retaining the copper foil pattern required to form the coil, thereby directly forming the first coil 20 and the second coil 30 on the substrate 10. The entire process is a subtractive processing of the original copper foil on the substrate 10, forming the coil by removing excess parts, rather than bonding new copper foil to the substrate 10.

[0068] If the substrate 10 adopts the existing ceramic substrate 10, phenolic paper laminate, etc., copper foil can be bonded to the first end face and the second end face of the substrate 10 respectively. Then, by using the direct printing process, through a series of steps such as photolithography and etching, the copper foil is precisely made on the first end face and the second end face of the substrate 10 according to the designed coil pattern to form the first coil 20 and the second coil 30.

[0069] Therefore, using copper foil to directly form coils offers higher production efficiency and precision compared to traditional winding methods. The direct-form-printing process allows for precise control of the coil's shape, size, and number of turns, avoiding errors that may occur during manual winding and ensuring consistent and stable coil performance. Furthermore, this process is suitable for mass production, effectively reducing production costs, increasing efficiency, and meeting the substantial market demand for wireless transmission coil components.

[0070] In other embodiments, both the first coil 20 and the second coil 30 are made of graphene copper and are formed on the substrate 10 using a direct printing process.

[0071] The substrate 10 can be a ceramic substrate 10 or a phenolic paper laminate, as used in existing technologies. Graphene composite copper foil is bonded to the first and second end faces of the substrate 10, respectively. Specifically, the graphene composite copper foil includes a graphene layer and a copper foil layer; or graphene copper powder is deposited on the first and second end faces of the substrate 10 to obtain the graphene composite copper foil. Then, using a direct printing process, through a series of steps such as photolithography and etching, the graphene composite copper foil is precisely fabricated on the first and second end faces of the substrate 10 according to the designed coil pattern, forming the first coil 20 and the second coil 30.

[0072] Because graphene copper has a lower resistivity than pure copper, compared to traditional copper coils, the first coil 20 and the second coil 30 made of graphene copper can effectively reduce resistance loss during current transmission and reduce copper loss. When the copper coil and the graphene copper coil are of the same thickness, the graphene copper coil can reduce impedance during current transmission and improve energy utilization efficiency. Simultaneously, its excellent conductivity allows the coil to maintain stable current transmission even under high-frequency alternating current, generating a more uniform and stable alternating magnetic field, enhancing the electromagnetic coupling effect with the receiving coil, and significantly improving the efficiency and stability of wireless charging, making it particularly suitable for applications requiring high charging speed and stability.

[0073] Furthermore, the thickness of the substrate 10 is H1, and the value of H1 ranges from 0.08mm to 0.12mm. The cross-sections of the first coil segment 23 and the second coil segment are both rectangular, and the thickness of the rectangle is H2, with a value range of 0.15mm to 0.3mm. The width of the rectangle is L, with a value range of 2.15mm to 2.45mm.

[0074] The substrate 10 adopts existing technologies such as ceramic substrate 10 and phenolic paper laminate, with a thickness of H1, and the value of H1 ranges from 0.08mm to 0.12mm. The substrate 10 with this thickness range can ensure the mechanical strength of the substrate 10, while ensuring the accuracy of photolithography, etching and other operations in the subsequent printing direct molding process, and at the same time, it is convenient to process through holes 12 and deposit conductive layers.

[0075] For the first coil 20 and the second coil 30, the copper foil or graphene composite copper foil can be processed into rectangular coil segments by controlling the etching depth during photolithography and etching processes. The thickness H2 of the rectangular cross-section ranges from 0.15mm to 0.3mm, and the width L ranges from 2.15mm to 2.45mm. A suitable coil thickness ensures sufficient current carrying capacity and reduces copper losses; a suitable coil width optimizes the magnetic field distribution, making the generated alternating magnetic field more uniform and the electromagnetic coupling between the coil and the receiving coil more stable, thereby improving the efficiency and stability of wireless charging.

[0076] Furthermore, when both the first coil 20 and the second coil 30 are made of copper foil, H1=0.1mm, H2=0.28mm, and L=2.27mm.

[0077] At this point, an 8-ounce copper foil can be bonded to both end faces of a 0.1 mm thick substrate 10. The copper foil is then processed into a first coil 20 and a second coil 30 with rectangular cross-sections. The thickness H2 of the rectangular cross-section is 0.28 mm, and the width L is 2.27 mm. The current-carrying area of ​​the first coil 20 and the second coil 30 is 0.636 mm². It should be noted that existing WPC QI2.0 compliant coils consist of 11 turns of type 1 Litz wire, each turn composed of 65 individual insulated copper wires with a diameter of 80 μm. The cross-sectional area of ​​the copper wire carrying current is 0.327 mm², the coil thickness is approximately 1.03 mm, and the thickness of the magnetic sheet body is approximately 1.15 mm. The total thickness of the coil and the magnetic sheet body is between 2.18 mm, which is relatively large.

[0078] In this application, the cross-sectional area for current flow is increased by 0.309 mm² compared to the coils in the prior art, enhancing the coil's current-carrying capacity. Simultaneously, the overall thickness of the coil assembly and substrate 10 is 0.66 mm, and the overall thickness after assembly with the magnetic sheet body is 1.81 mm, resulting in a total thickness reduction of 0.37 mm compared to the coils in the prior art. This allows the wireless transmission coil assembly of this invention to be smaller in size for various applications, such as charging small devices like mobile phones and smartwatches, making it adaptable to the internal space of the device and enabling stable wireless charging.

[0079] When both the first coil 20 and the second coil 30 are made of graphene copper, H1=0.1mm, H2=0.175mm, and L=2.27mm.

[0080] At this point, a 5-ounce thick graphene composite copper foil can be bonded to the two end faces of a 0.1 mm thick substrate 10. The copper foil is then processed into a first coil 20 and a second coil 30 with rectangular cross-sections. The thickness H2 of the rectangular cross-section is 0.175 mm, and the width L is 2.27 mm. The current-carrying area of ​​the first coil 20 and the second coil 30 is 0.397 mm²; their cross-sectional area for current flow is increased by 0.07 mm² compared to the coils in the prior art. This balances inductance and resistance losses when generating an alternating magnetic field, ensuring efficient energy transfer.

[0081] Meanwhile, the overall thickness of the coil assembly and substrate 10 is 0.45 mm, and the overall thickness after assembly with the magnetic sheet body is 1.6 mm, a reduction of 0.58 mm in total thickness compared to the coils in the prior art. In some space-constrained applications, such as portable electronic devices like mobile phones and tablets, the thinner coil assembly of this application can save internal space, facilitating the design of thinner and lighter devices, improving portability, and providing more space for the layout of other electronic components, thus helping to improve the overall performance and functional integration of the device.

[0082] Furthermore, the first coil segment 23 has N turns, the second coil segment has M turns, and N+M≥11.

[0083] Based on this structure, when fabricating the first coil 20 and the second coil 30 using photolithography and etching processes, the first coil segment 23 with N turns and the second coil segment with M turns can be gradually formed by repeating the photolithography and etching steps multiple times.

[0084] When the coil assembly is connected to the wireless charging system, the alternating current flowing through the first coil segment 23 and the second coil segment generates corresponding inductive effects in the circuit using coils with N and M turns. During operation, the number of coil turns, along with other parameters, works to generate an alternating magnetic field that meets the requirements. When charging mobile devices such as mobile phones and tablets, the input current and operating frequency are adjusted according to the device's charging power requirements. Coils with N and M turns achieve efficient and stable wireless charging through stable electromagnetic induction. By optimizing the number of turns, charging power and transmission efficiency are improved, meeting the demands of high-power charging.

[0085] The coil has at least 11 turns, ensuring the performance stability of the coil assembly under different environments and operating conditions. Even under the influence of factors such as temperature changes and external interference, sufficient turns can ensure that the coil maintains basic inductance and magnetic field performance, avoiding performance fluctuations caused by insufficient turns, thereby improving the reliability and lifespan of the entire wireless charging system.

[0086] Furthermore, increasing the number of coil turns (N+M≥11) can effectively increase the coil's inductance. In wireless charging systems, appropriate inductance helps improve power transfer efficiency. Simultaneously, increasing the number of turns also strengthens the magnetic field generated by the coil, enabling stronger electromagnetic coupling with the receiving coil under the same current conditions, thereby improving the stability and efficiency of energy transfer. In addition, a well-designed number of turns can optimize the coil's impedance matching, reduce signal reflection and energy loss, and ensure good electrical performance at different operating frequencies.

[0087] Furthermore, N=M, and N+M=11.

[0088] Where N=M=5.5, the magnetic field strength generated by the first coil segment 23 and the second coil segment is basically the same and symmetrical in direction. This symmetrical magnetic field distribution greatly improves the uniformity of the magnetic field and reduces magnetic field distortion. During wireless charging, the receiving coil can more stably sense the electromotive force, avoiding charging efficiency fluctuations and local overheating caused by uneven magnetic field, thus improving the stability and consistency of energy transmission. This is especially suitable for precision electronic devices with high requirements for charging stability.

[0089] When the component is connected to the wireless charging system, the alternating current simultaneously passes through the first coil segment 23 and the second coil segment, which have the same number of turns. When charging mobile devices such as mobile phones and tablets, because the two coils have the same number of turns, the magnetic field strength and distribution generated are more balanced, which can provide a stable and uniform electromagnetic induction for the receiving coil, achieving efficient and stable wireless charging.

[0090] Furthermore, it also includes a magnetic sheet body, with the substrate 10 and the coil assembly mounted on the magnetic sheet body, and both the first terminal 22 and the second terminal 31 extending out from the outer periphery of the magnetic sheet body.

[0091] Based on this structure, during assembly, the assembled substrate 10 and coil assembly can be glued to the magnetic sheet body, or the assembled substrate 10 and coil assembly can be installed into the receiving slot on the magnetic sheet body. After installation, the first terminal 22 and the second terminal 31 extend from the outer periphery of the magnetic sheet body, at which point they can be connected to external circuits. By soldering, plugging, or other methods, the terminals can be connected to external circuit components such as power supplies and control modules to form a complete wireless charging circuit.

[0092] The magnetic sheet body is circular and sheet-like with a certain thickness, made of high-permeability materials such as permalloy and ferrite. Due to its excellent magnetic permeability, the magnetic sheet body can effectively guide and concentrate the magnetic field generated by the coil assembly. When the substrate 10 and the coil assembly are mounted on the magnetic sheet body, the magnetic sheet body converges and guides the divergent magnetic field generated by the coil, making the magnetic field more concentrated and orderly propagating. This not only increases the magnetic field strength but also enhances its directionality, enabling more efficient electromagnetic coupling with the receiving coil at the same power, thus improving the transmission efficiency and stability of wireless charging.

[0093] Meanwhile, the magnetic sheet body provides physical protection for the substrate 10 and the coil assembly. During transportation and use, the magnetic sheet body can withstand external mechanical impacts and vibrations, preventing damage to the substrate 10 and the coil assembly. It should be noted that since the first terminal 22 and the second terminal 31 extend from the outer periphery of the magnetic sheet body, they can be directly connected to external circuits, eliminating the need for slots in the magnetic sheet body to bring out terminals located inside the coils, as in related technologies. In other words, the magnetic sheet body structure of this invention is complete, has good strength, and can better provide reliable support for the substrate 10 and the coil assembly.

[0094] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A wireless transmission coil assembly, characterized in that: include, A substrate having a first end face and a second end face, the first end face and the second end face being disposed opposite to each other; the substrate having an electrically conductive portion. The coil assembly includes a first coil and a second coil. The first coil is disposed on the first end face, and the second coil is disposed on the second end face. The first coil has a first connecting end and a first wiring end at both ends, and the second coil has a second connecting end and a second wiring end at both ends. The first connecting end and the second connecting end are electrically connected to the electrically conductive part so that the first coil and the second coil are electrically connected. The first wiring end and the second wiring end both extend from the outer periphery of the substrate.

2. The wireless transmission coil assembly according to claim 1, characterized in that: The electrically conductive part includes a plurality of through holes, which extend from the first end face to the second end face; a conductive element is provided in the through hole, and the two ends of the conductive element are electrically connected to the first connection end and the second connection end, respectively.

3. The wireless transmission coil assembly according to claim 2, characterized in that: The conductive element includes a conductive post, which is embedded in the through hole, and the conductive post is made of copper or graphene copper.

4. The wireless transmission coil assembly according to claim 2, characterized in that: The conductive element includes a conductive layer made of copper or graphene copper, which is deposited in the via by physical vapor deposition or chemical vapor deposition.

5. The wireless transmission coil assembly according to claim 1, characterized in that: A plurality of first coil segments are provided between the first connecting end and the first wiring end, and the plurality of first coil segments are wound around the axis of the substrate; a plurality of second coil segments are provided between the second connecting end and the second wiring end, and the plurality of second coil segments are wound around the axis of the substrate; the plurality of first coil segments and the plurality of second coil segments are arranged radially along the substrate.

6. The wireless transmission coil assembly according to claim 5, characterized in that: Both the first coil and the second coil are made of copper foil and are formed on the substrate using a direct printing process.

7. The wireless transmission coil assembly according to claim 5, characterized in that: Both the first coil and the second coil are made of graphene copper and are formed on the substrate using a direct printing process.

8. The wireless transmission coil assembly according to claim 6 or 7, characterized in that: The thickness of the substrate is H1, and the value of H1 ranges from 0.08mm to 0.12mm; the cross-sections of the first coil segment and the second coil segment are both rectangular, the thickness of the rectangle is H2, and the value of H2 ranges from 0.15mm to 0.3mm; the width of the rectangle is L, and the value of L ranges from 2.15mm to 2.45mm.

9. The wireless transmission coil assembly according to claim 8, characterized in that: When both the first coil and the second coil are made of copper foil, H1 = 0.1 mm, H2 = 0.28 mm, and L = 2.27 mm; when both the first coil and the second coil are made of graphene copper, H1 = 0.1 mm, H2 = 0.175 mm, and L = 2.27 mm.

10. The wireless transmission coil assembly according to claim 5, characterized in that: The first coil segment has N turns, and the second coil segment has M turns, where N+M≥11.

11. The wireless transmission coil assembly according to claim 10, characterized in that: N=M, and N+M=11.

12. The wireless transmission coil assembly according to any one of claims 1-7 or 10-11, characterized in that: It also includes a magnetic sheet body, the substrate and the coil assembly are mounted on the magnetic sheet body, and the first terminal and the second terminal both extend from the outer periphery of the magnetic sheet body.

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