Coil module, electronic equipment and wireless charging system

Abstract

The invention provides a coil module, electronic equipment and a wireless charging system, relates to the technical field of wireless charging, and aims to solve the problem that the thickness of a wireless charging coil module is relatively large and is not beneficial to setting of other functional devices in the electronic equipment. The coil module comprises a coil structure; the coil structure comprises a functional layer, and the functional layer comprises a first wiring sub-layer, a second wiring sub-layer and an insulator layer located between the first wiring sub-layer and the second wiring sub-layer in the thickness direction of the coil structure. The coil structure further comprises a first end, a second end and a plurality of coil groups which are sequentially connected in series, the first end and the plurality of coil groups are arranged on the first wiring sub-layer, and the coil group on the outermost circle is connected with the first end; the second end is arranged on the second wiring sub-layer; a via hole is formed in the insulator layer, and a connecting structure is arranged in the via hole; and the innermost coil group is connected with the second end through a connecting structure in the insulator layer, so that the first end is electrically connected with the second end through a plurality of coil groups which are sequentially connected in series.

Description

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on January 11, 2024, with application number 202410047758.4 and application name “Coil module, electronic device and wireless charging system”, the entire contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of wireless charging technology, and in particular to a coil module, an electronic device and a wireless charging system. Background Art

[0003] Since wireless charging is safer, more reliable and easier to use than wired charging, more and more electronic devices, such as mobile phones, tablets, smart watches, etc., are using wireless charging technology. A core component for wireless charging technology is the wireless charging coil module.

[0004] However, the thickness of the existing wireless charging coil module is relatively thick, which is not conducive to the arrangement of functional devices (such as functional devices corresponding to biometrics, high-quality imaging, artificial intelligence, etc.) in electronic devices with increasing functions (such as biometrics, high-quality imaging, artificial intelligence, etc.). How to solve the above problem is an issue that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a coil module, an electronic device and a wireless charging system to solve the problem that the thickness of the wireless charging coil module in the prior art is relatively thick, which is not conducive to the arrangement of other functional components in the electronic device.

[0006] In a first aspect, an embodiment of the present application provides a coil module, which includes: a coil structure; the coil structure includes a functional layer, and along the thickness direction of the coil structure, the functional layer includes a first wiring sublayer, a second wiring sublayer and an insulating sublayer located between the first wiring sublayer and the second wiring sublayer; the coil structure also includes a first end, a second end and a plurality of coil groups connected in series in sequence, the first end and the plurality of coil groups are arranged in the first wiring sublayer, and the coil group in the outermost circle is connected to the first end; the second end is arranged in the second wiring sublayer; a via is provided on the insulating sublayer, and a connecting structure is provided in the via; the coil group in the innermost circle is connected to the second end through the connecting structure in the insulating sublayer, so that the first end is electrically connected to the second end through the plurality of coil groups connected in series in sequence.

[0007] In the present application, multiple coil groups occupying a larger area are arranged on the first wire sub-layer, and the second wiring sub-layer only includes a second end occupying a smaller area. In this way, when the coil module is arranged in an electronic device, other wiring of the electronic device can be arranged on the second wiring sub-layer to avoid other wiring occupying the internal space of the electronic device, which is conducive to the arrangement of other structures. Alternatively, since the second wiring sub-layer only has a second end occupying a smaller area, the second end occupying a smaller area can be embedded in other structures of the electronic device, so that the coil module occupies less space inside the electronic device, which is conducive to the arrangement of other structures.

[0008] Exemplarily, the thickness direction of the coil structure may be the thickness direction of the electronic device or the direction of the central axis passing through the centers of the multiple coil groups. The thickness direction of the coil structure is perpendicular to the first wiring sublayer, the second wiring sublayer and the insulating sublayer.

[0009] According to the first aspect, the coil module further includes: a magnetic conductive layer; the magnetic conductive layer includes a hollow portion, and the second end is arranged in the hollow portion.

[0010] The setting of the magnetic conductive layer can concentrate the magnetic field, improve the coil inductance of the coil module, and can also shield part of the magnetic field, reducing the eddy current loss generated by the magnetic field on some structures of the electronic equipment (such as the middle frame, battery, printed circuit board, etc.). In addition, by embedding the second end of the coil structure in the magnetic conductive layer, the occupation of the second end in the thickness direction of the coil module can be avoided, the thickness of the coil module is reduced, and the thickness of the wireless charging coil can be made extremely thin, which is extremely advantageous in terms of thickness. For example, the thickness of the coil module is less than 0.2mm. For example, the thickness of the coil module is only 0.1Xmm (where X is 1, 2, 3, 4, 5, 6, 7, 8, 9, etc., that is, the thickness of the coil module is only 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm or 0.19mm). Of course, it can also be less than 0.1mm.

[0011] According to the first aspect, or any implementation of the first aspect above, along the thickness direction of the coil structure, the magnetic conductive layer includes a first protective sublayer, a second protective sublayer and a magnetic conductive sublayer located between the first protective sublayer and the second protective sublayer, and the magnetic conductive sublayer includes multiple layers of adhesive and nanocrystals located between two adjacent layers of adhesive; the first protective sublayer is arranged adjacent to the coil structure, and the adhesive arranged adjacent to the second protective sublayer is the first adhesive; the first protective sublayer, other adhesives except the first adhesive, and the film layer where the nanocrystals are located are provided with a first opening, and the film layer where the first adhesive and the second protective sublayer are located are provided with a second opening, and the first opening and the second opening form a hollow portion; the projection of the second opening on the reference plane is located within the projection of the first opening on the reference plane, and the reference plane is perpendicular to the thickness direction of the coil structure.

[0012] The openings of the first adhesive and the second protective sublayer are made smaller, that is, the first adhesive and the second protective sublayer extend a portion toward the edge of the hollow portion, so that the nanocrystalline powder can be prevented from falling out, making the structure of the coil module more reliable.

[0013] Exemplarily, the reference plane is parallel to the first wiring sub-layer, and other film layers in the coil module are parallel to each other.

[0014] Exemplarily, the magnetic conductive sublayer includes three layers of adhesive and two layers of nanocrystals located between two adjacent layers of adhesive.

[0015] According to the first aspect, or any implementation of the first aspect above, the coil structure also includes a flexible circuit board unit; the flexible circuit board unit is located in a preset area of ​​the second wiring sublayer, and the preset area is an area in the second wiring sublayer where no second end is provided.

[0016] That is to say, when the coil module is provided in an electronic device, the flexible circuit board in the electronic device can be provided in the second wiring sublayer, that is, the coil module includes both the wireless charging coil and the flexible circuit board in the electronic device. In this way, the occupation of the internal space of the electronic device by other flexible circuit boards is avoided, which is conducive to the setting of other structures and can also reduce the process steps.

[0017] According to the first aspect, or any implementation of the first aspect above, the preset area includes a first sub-area, and the first sub-area is an area formed by the projection of the outermost coil group on the second wiring sublayer extending by a first preset length in all directions; when the line width of the flexible circuit board unit in the first sub-area is greater than the second preset length, the routing of the flexible circuit board unit in the first sub-area is cut into multiple lines.

[0018] That is, the wider traces of the flexible circuit board unit in the first sub-region are cut into a plurality of thin traces, so as to avoid excessive eddy current loss on the wider traces.

[0019] For example, the first preset length may be 5 mm, and the second preset length may be 8 mm.

[0020] According to the first aspect, or any implementation of the first aspect above, the coil module further includes: a magnetic conductive layer; along the thickness direction of the coil structure, the magnetic conductive layer is located on a side of the second wiring sublayer away from the first wiring sublayer.

[0021] The magnetic conductive layer is arranged on the side of the second wiring sublayer away from the first wiring sublayer, that is, the first wiring sublayer including the coil group is arranged away from the nanocrystal side, which is beneficial to improve the mutual inductance and improve the wireless charging performance.

[0022] Of course, the magnetic conductive layer may also be located on a side of the first wiring sub-layer away from the second wiring sub-layer.

[0023] According to the first aspect, or any implementation of the first aspect, the number of coil groups is N, where N is less than or equal to 8 and greater than or equal to 7.

[0024] This arrangement enables the coil structure to achieve both high-power and high-freedom wireless charging effects.

[0025] Exemplarily, the number of coil groups is 7 or 8, and of course, it can also be 7.5 or the like.

[0026] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 7, the thickness of the first wiring sublayer is greater than or equal to 25μm and less than or equal to 40μ, and each coil group includes M strands of wire, M is greater than or equal to 3.

[0027] With this arrangement, even if the coil assembly is thicker, it is possible to avoid generating large eddy current losses on the thicker coil assembly.

[0028] Exemplarily, M is 4.

[0029] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 7, the thickness of the first wiring sublayer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 4.

[0030] Because the M strands of wire are formed by cutting the wires, when M is less than or equal to 4, it is possible to avoid wasting a lot of wiring space and also achieve a better flow effect.

[0031] Exemplarily, M is 3.

[0032] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 8, the thickness of the first wiring sublayer is greater than or equal to 25μm and less than or equal to 40μ, and each coil group includes M strands of wire, M is greater than or equal to 2.

[0033] With this arrangement, even if the thickness of the coil group is relatively thick, large eddy current losses can be avoided on the thicker coil group, and the impedance will not be increased due to the increase in the number of coil groups.

[0034] Exemplarily, M is 3.

[0035] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is 8, the thickness of the first wiring sublayer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 3.

[0036] Because the M strands of wire are formed by cutting and routing, when M is less than or equal to 4, it can avoid wasting a lot of routing space and can also have a better current flow effect. And it will not have a larger impedance due to the increase in the number of coil groups.

[0037] Exemplarily, M is 3.

[0038] According to the first aspect, or any implementation of the first aspect above, the widths of the multiple coil groups gradually increase in a direction away from the center of the coil structure, so that the current distribution is more uniform.

[0039] Exemplarily, the number of coil groups is 8, and the coil groups from the innermost circle to the outermost circle are the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The width of the multiple coil groups gradually increases, which can be the width of the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The width of the multiple coil groups gradually increases, which can also be the width of some adjacent coil groups in the 8 coil groups being the same, and the width of the coil groups with different widths gradually increases along the direction away from the center of the coil structure, such as the first coil group and the second coil group having the same width, the third coil group, the fourth coil group, and the fifth coil group having the same width, the sixth coil group, the seventh coil group, and the eighth coil group having the same width, and the width of the first coil group, the third coil group, and the sixth coil group increasing in sequence; for another example, the width of the third coil group, the fourth coil group, and the fifth coil group having the same width, the width of the sixth coil group and the seventh coil group having the same width, and the width of the first coil group, the second coil group, the third coil group, the sixth coil group, and the eighth coil group increasing in sequence.

[0040] Exemplarily, the number of strands in each coil group may be the same, such as 3 strands or 4 strands.

[0041] According to the first aspect, or any implementation of the first aspect above, the number of coil groups is N, the N coil groups include L internal coil groups and (NL) external coil groups arranged around the L internal coil groups; each coil group includes multiple strands of wire; the number of wire strands located in the external coil group is greater than the number of wire strands located in the internal coil group.

[0042] This arrangement makes the current distribution more uniform.

[0043] Exemplarily, the number of coil groups is N groups, and the coil groups from the innermost circle to the outermost circle are the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group have the same number of strands, the first coil group, the second coil group, the third coil group, and the fourth coil group have the same number of strands, and the eighth coil group has a larger number of strands than the first coil group; or the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group have the same number of strands, the fourth coil group and the fifth coil group have the same number of strands, the first coil group, the second coil group, and the third coil group have the same number of strands, the eighth coil group has a larger number of strands than the fifth coil group, and the fifth coil group has a larger number of strands than the first coil group.

[0044] According to the first aspect, or any implementation of the first aspect above, the coil structure is an FPC coil.

[0045] The FPC coil has good flatness and is relatively thin, which further facilitates the lightweight design of the equipment using the coil module.

[0046] In a second aspect, an embodiment of the present application provides an electronic device, comprising: the coil module of the first aspect and any one of the first aspect.

[0047] The second aspect corresponds to the first aspect and any implementation of the first aspect. The technical effects corresponding to the second aspect can refer to the technical effects corresponding to the first aspect and any implementation of the first aspect, which will not be repeated here.

[0048] According to the second aspect, the coil structure also includes at least one flexible circuit board unit; the flexible circuit board unit is located in a preset area of ​​the second wiring sublayer, and the preset area is an area in the second wiring sublayer where no second end is provided; the electronic device also includes a printed circuit board, and the flexible circuit board unit is connected to the printed circuit board.

[0049] The flexible circuit board connected to the printed circuit board in the electronic device can be arranged on the second wiring sublayer, that is, the coil module includes both the wireless charging coil and the flexible circuit board in the electronic device. In this way, other flexible circuit boards are avoided from occupying the internal space of the electronic device, which is conducive to the arrangement of other structures and can also reduce the process steps.

[0050] Exemplarily, only one flexible circuit board connected to the printed circuit board in the electronic device can be arranged in the second wiring sublayer, two flexible circuit boards connected to the printed circuit board in the electronic device can be arranged in the second wiring sublayer, or multiple (such as three or more) flexible circuit boards connected to the printed circuit board in the electronic device can be arranged in the second wiring sublayer.

[0051] According to the second aspect, or any implementation of the second aspect, the printed circuit board includes a main board and a sub-board, and the main board is connected to the sub-board through a flexible circuit board unit.

[0052] That is, setting the flexible circuit board connecting the main board and the sub-board on the second wiring sub-layer can reduce the occupation of the internal space of the electronic device by the flexible circuit board, compared with setting the flexible circuit board connecting the main board and the sub-board in the accommodation space of the electronic device, which is conducive to the setting of other structures.

[0053] According to the second aspect, or any implementation of the second aspect, the electronic device further includes a functional device, and the functional device is connected to the printed circuit board through the flexible circuit board unit.

[0054] That is, setting the flexible circuit board connecting the functional devices and the printed circuit board on the second wiring sublayer can reduce the occupation of the internal space of the electronic device by the flexible circuit board, compared with setting the flexible circuit board connecting the functional devices and the printed circuit board in the accommodation space of the electronic device, which is conducive to the setting of other structures.

[0055] Exemplarily, the functional device includes a speaker or a SIM card. Of course, the functional device is not limited thereto.

[0056] According to the second aspect, or any implementation of the second aspect above, the flexible circuit board unit is configured as an NFC coil. That is, the NFC coil is configured in the second wiring sublayer, which can reduce the occupation of the internal space of the electronic device by the flexible circuit board compared to configuring the NFC coil in the accommodation space of the electronic device, and is conducive to the configuration of other structures.

[0057] According to the second aspect, or any implementation of the second aspect above, the electronic device includes a wireless charging receiving device or a wireless charging sending device. That is, the receiving coil of the wireless charging receiving device can be the coil module of the first aspect and any one of the first aspects, and / or the transmitting coil of the wireless charging sending device can be the coil module of the first aspect and any one of the first aspects.

[0058] In a third aspect, an embodiment of the present application provides a wireless charging system, which includes: the second aspect and the electronic device of any one of the second aspect.

[0059] The third aspect corresponds to the second aspect and any implementation of the second aspect. The technical effects corresponding to the third aspect and any implementation of the third aspect can refer to the technical effects corresponding to the above-mentioned second aspect and any implementation of the second aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic diagram of the structure of a wireless charging system provided in an embodiment of the present application;

[0061] Figure 2 A schematic diagram of a circuit structure of a wireless charging system provided in an embodiment of the present application;

[0062] Figure 3 for Figure 1 The structural schematic diagram of the wireless charging receiving device shown;

[0063] Figure 4 A film layer diagram of a coil module provided in Example 1 of the present application;

[0064] Figure 5a A three-dimensional diagram of a coil module provided in Example 1 of the present application;

[0065] Figure 5b for Figure 5a A plan view of the coil module shown;

[0066] Figure 5c for Figure 5a An exploded view of the coil structure in the coil module shown;

[0067] Figure 5d for Figure 5a An exploded view of the coil module shown;

[0068] Figure 6 This is an exploded view of another coil module provided in the first embodiment of the present application;

[0069] Figure 7 This is an exploded view of another coil module provided in the first embodiment of the present application;

[0070] Figure 8 This is an exploded view of another coil module provided in the first embodiment of the present application;

[0071] Fig. 9 A simulation diagram of current density distribution on a coil module provided in Example 1 of the present application;

[0072] Fig.10 A simulation diagram of current density distribution on another coil module provided in the first embodiment of the present application;

[0073] Fig.11A simulation diagram of current density distribution on another coil module provided in the first embodiment of the present application;

[0074] Fig.12 A film layer diagram of a coil module provided in Example 2 of the present application;

[0075] Fig.13 A plan view of a coil module provided in Embodiment 2 of the present application;

[0076] Fig.14 for Fig.13 Exploded view of the coil module shown. DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0078] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0079] The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects rather than to describe a specific order of objects. For example, a first target object and a second target object are used to distinguish different target objects rather than to describe a specific order of target objects.

[0080] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0081] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more than two. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0082] The connection relationship described in this application refers to direct or indirect connection. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components. For example, A can be directly connected to C, and C can be directly connected to B, so that A and B are connected through C. It is also understandable that the "A connected to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0083] First, the terms involved in this application are explained:

[0084] Layer refers to the number of planes in which the wires contained in the coil provided by the present application are arranged. When all the wires contained in a coil are wound on the same plane to form a planar coil, the coil is a one-layer wound coil; when all the wires contained in a coil are not arranged on the same plane, for example, the first wire is wound on the first planar layer, the second wire is wound on the second planar layer, and the first wire and the second wire are connected through a via in the insulating layer between the first planar layer and the second planar layer, the coil is a two-layer wound coil.

[0085] The number of turns refers to the number of turns of the wire winding in each coil.

[0086] The number of strands refers to the number of parallel wires in each turn of the coil when the coil is wound.

[0087] Next, the technical scenarios involved in the embodiments of the present application are described.

[0088] The technical solution of the present application is applied to the wireless charging technology scenario. The scenario includes a wireless charging device and a device to be charged. Among them, the wireless charging device is used to charge the device to be charged with a wireless charging function. For example, the wireless charging device can be a wireless charging mobile power supply, a wireless charging plate, a wireless charger, etc., and the device to be charged can be a mobile phone, a tablet, a laptop computer, a personal digital assistant (PDA for short), a car computer, a smart wearable device (such as a smart watch, a smart bracelet, a headset, etc.), virtual reality (VR), augmented reality (AR) and other electronic devices. The above-mentioned device to be charged can also be a wireless charging electric car, a wireless charging household appliance (such as a sweeping robot, etc.), a drone and other electronic products. For another example, the wireless charging device can be a tablet, a laptop computer, a mobile phone, etc., and the device to be charged can be a stylus, a magnetic keyboard, etc.

[0089] The wireless charging device mentioned above may also be referred to as a wireless charging transmitting device, and the device to be charged may also be referred to as a wireless charging receiving device.

[0090] In order to enable those skilled in the art to better understand the technical solution provided by the embodiments of the present application, the following briefly introduces the wireless charging principle in the wireless charging technology scenario. The description is made by taking the wireless charging transmitting device as a wireless charger and the wireless charging receiving device as a mobile phone as an example, and the other contents below are also described by taking the wireless charging transmitting device as a wireless charger and the wireless charging receiving device as a mobile phone as an example.

[0091] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a wireless charging system provided in an embodiment of the present application. Figure 1 As shown, the wireless charging system 01 includes a wireless charging transmitting device 10 and a wireless charging receiving device 20. The wireless charging transmitting device 10 may be a wireless charger, and the wireless charging receiving device 20 may be a mobile phone, and the wireless charger performs wireless charging for the mobile phone.

[0092] It should be noted that Figure 1 The wireless charger shown has a certain inclination so that the mobile phone can lean against the wireless charger. Of course, this does not constitute a limitation of the present application. In other optional embodiments of the present application, the wireless charger can also have other forms, for example, the wireless charger is in the shape of a flat plate, and the wireless charger supports the mobile phone to be placed horizontally above it.

[0093] See also Figure 2 , Figure 2 A schematic diagram of the circuit structure of a wireless charging system provided in an embodiment of the present application. Figure 2 As shown, the wireless charging transmission device 10 includes a power source 11 and a wireless transmission device 12 .

[0094] The power supply 11 is used to provide a DC voltage, wherein the DC voltage provided by the power supply 11 is a first DC voltage in order to distinguish it from other DC voltages.

[0095] The wireless transmitting device 12 includes a direct current (DC) / alternating current (AC) circuit 122 , a resonant capacitor C1 , and a transmitting coil L1 .

[0096] In some embodiments, the wireless transmitting device 12 further includes a voltage conversion circuit 121. The voltage conversion circuit 121 is electrically connected to the power supply 11, and is used to convert the first DC voltage output by the power supply 11 into a stable second DC voltage. Exemplarily, the voltage conversion circuit 121 can be a boost circuit (such as a boost circuit, a boost transformer, or a power amplifier, etc.), which is used to boost the first DC voltage output by the power supply 11 and then output it.

[0097] When the voltage conversion circuit 121 is a boost circuit, the potential difference between the wireless charging transmitting device 10 and the wireless charging receiving device 20 can be increased, and the energy transfer capability of the system can be improved, which is beneficial to high-power transmission.

[0098] Of course, the voltage conversion circuit 121 is not limited to a boost circuit, but can also be a buck circuit for outputting the first DC voltage output by the power supply 11 after stepping down the voltage. Those skilled in the art can configure the voltage conversion circuit 121 according to actual conditions.

[0099] The DC / AC circuit 122 is electrically connected to the voltage conversion circuit 121, and is used to convert the second DC voltage output by the voltage conversion circuit 121 into AC power. Exemplarily, the DC / AC circuit 122 may be an inverter bridge, and its circuit structure may be a full-bridge circuit or a half-bridge circuit. The DC / AC circuit 122 is also called a transmit (TX) chip.

[0100] The resonant capacitor C1 and the transmitting coil L1 are connected in series to form a series resonant network, and the transmitting coil L1 is electrically connected to the DC / AC circuit 122 via the resonant capacitor C1. In the process of the DC / AC circuit 122 charging and discharging the resonant capacitor C1 and the transmitting coil L1, the transmitting coil L1 can convert the alternating current into an alternating magnetic field.

[0101] Combination Figure 3 , Figure 3 for Figure 1 The schematic diagram of the structure of the wireless charging receiving device is shown in FIG. Figure 3As shown, a wireless charging receiving device 20, such as a mobile phone, includes a rear shell 201, a display screen 202 and a middle frame 203, wherein the display screen 202 and the rear shell 201 are respectively located on both sides of the middle frame 203, and the rear shell 201, the display screen 202 and the middle frame 203 can enclose a receiving cavity. The receiving cavity is provided with structures such as a printed circuit board (PCB) 204, a battery 205, a speaker (not shown in the figure), a SIM card holder for carrying a SIM card, and a near field communication (NFC) coil (not shown in the figure). In an embodiment of the present application, the PCB 204 includes a main board 2041 and a sub-board 2042, and the main board 2041 and the sub-board 2042 can be connected via a flexible printed circuit (FPC).

[0102] Continue to see Figure 2 and Figure 3 The wireless charging receiving device 20 also includes a wireless receiving device 22 and a load 21. The load 21 is a load resistance equivalent to the power unit at the back end of the system. The load 21 can be a battery or other device that needs to be charged.

[0103] The wireless receiving device 22 includes a receiving coil L2 , a resonant capacitor C2 and an AC / DC circuit 222 .

[0104] The receiving coil L2 is located in the accommodating cavity, and illustratively, can be located between the battery 205 and the rear housing 201. The receiving coil L2 can be connected to the PCB 204 via an FPC (not shown in the figure).

[0105] The resonant capacitor C2 and the AC / DC circuit 222 are arranged on the PCB 204 (such as the main board 2041 ), and the receiving coil L2 is connected to the resonant capacitor C2 and the AC / DC circuit 222 through the FPC and the PCB 204 (signal transmission and interaction can be performed). In addition, the AC / DC circuit 222 is also connected to the load 21 .

[0106] When the wireless charging transmitting device 10 needs to charge the wireless charging receiving device 20, the receiving coil L2 is close to or attached to the transmitting coil L1. At this time, the receiving coil L2 in the wireless charging receiving device 20 generates alternating current through electromagnetic induction, and the AC / DC circuit 222 converts the alternating current generated by the receiving coil L2 into direct current, and outputs it to the load 21 to power the load 21. Exemplarily, the AC / DC circuit 222 can be, for example, a rectifier bridge, and its circuit structure can be a full-bridge circuit or a half-bridge circuit. Among them, the AC / DC circuit 222 is also called a receiving (Receive, RX) chip.

[0107] In some embodiments, when the direct current output by the AC / DC circuit 222 is too large to be directly provided to the load 21, the wireless receiving device 22 may further include a voltage conversion circuit 221. The voltage conversion circuit 221 is electrically connected to the AC / DC circuit 222 and the load 21, respectively, and is used to reduce the larger voltage output by the AC / DC circuit 222 to the voltage required by the load 21. Exemplarily, the voltage conversion circuit 221 may be a step-down circuit (also called a buck circuit).

[0108] In some embodiments, the voltage conversion circuit 221 can also be a switched capacitor (Switch Capacitor Converter, SC) circuit (not shown in the figure). The SC circuit can achieve, for example, a 2:1, 4:1, etc. ratio of step-down conversion. The specific structure of the SC circuit and the principle of achieving step-down conversion can be referred to the existing technology.

[0109] In some embodiments, the wireless charging receiving device 20 can also perform wired charging. When the wireless charging receiving device 20 can perform wired charging, the wireless charging receiving device 20 also includes a USB interface, which is electrically connected to the voltage conversion circuit 221, and the charging signal received by the USB interface is transmitted to the voltage conversion circuit 221, so that the larger charging signal is reduced to the charging signal required by the load 21 through the voltage conversion circuit 221 to power the load 21. In some embodiments, an overvoltage protection (OVP) circuit is provided between the USB interface and the voltage conversion circuit 221, wherein the OVP circuit may include an OVP switch tube, which may be a MOS tube. When the OVP circuit detects that the voltage connected to the USB interface is too high (exceeding the threshold voltage), the connection between the voltage conversion circuit 221 and the USB interface can be actively cut off to protect the voltage conversion circuit 221.

[0110] The structure of the wireless charging system 01 is introduced above. It can be seen from the above content that the wireless charging technology uses the principle of electromagnetic coupling to realize power transmission, that is, the alternating current carried by the transmitting coil on the wireless charging transmitting device side generates a changing magnetic field, and the receiving coil on the wireless charging receiving device side generates an induced current in the changing magnetic field, thereby realizing the charging of the wireless charging receiving device side. Therefore, a major core component for realizing wireless charging technology is the wireless charging coil module, that is, the above-mentioned transmitting coil L1 and / or receiving coil L2. However, the thickness of the coil module in the prior art is relatively thick. For example, the thickness of the existing wireless charging coil module is generally between 0.2mm-0.3mm. This is not conducive to the setting of functional devices in electronic devices (such as functional devices corresponding to biometrics, functional devices corresponding to high-quality images, functional devices corresponding to artificial intelligence, etc.) for electronic devices with increasing functions (such as biometrics, high-quality images, artificial intelligence and other advanced functions).

[0111] In order to solve the above problems, the present application provides a coil module, which can be applied to a wireless charging receiving device, that is, the coil module can be a receiving coil in a wireless charging receiving device; it can also be applied to a wireless charging sending device, that is, the coil module can be a transmitting coil in a wireless charging sending device. The structure of the coil module provided in the embodiment of the present application is described in detail below.

[0112] It should be noted that the coil module provided in this application is not only suitable for wireless charging scenarios, but also for other scenarios that utilize the principle of electromagnetic induction.

[0113] Embodiment 1

[0114] See also Figure 4 , Figure 4 This is a film layer structure diagram of a coil module provided in Example 1 of the present application. Figure 4 As shown, the coil module 30 includes a coil structure 31 and a magnetic conductive layer 32 , and the coil structure 31 and the magnetic conductive layer 32 are fixed together by a double-sided adhesive layer (such as double-sided tape) 33 .

[0115] The provision of the magnetic conductive layer 32 can concentrate the magnetic field and improve the coil inductance of the coil module 30. In addition, it can be seen from the above content that the coil module 30 can be provided in the wireless charging receiving device 20, and the wireless charging receiving device 20 can include structures such as PCB 204, battery 205, and middle frame 203. However, structures such as PCB 204, battery 205, and middle frame 203 are generally metal, and the magnetic field will generate eddy current losses on PCB 204, battery 205, and middle frame 203. The provision of the magnetic conductive layer 32 can also shield part of the magnetic field and reduce the eddy current losses generated by the magnetic field on PCB 204, battery 205, and middle frame 203.

[0116] Exemplarily, the magnetic conductive layer 32 includes two protective sublayers 321 and a magnetic conductive sublayer 322 located between the two protective sublayers 321, wherein the two protective sublayers 321 may include a first protective sublayer and a second protective sublayer, and the first protective sublayer is disposed adjacent to the coil structure 31. The protective sublayer 321 may be a nanocrystalline black film or polyimide (PI). The magnetic conductive sublayer 322 includes a soft magnetic material, and the soft magnetic material includes ferrite or nanocrystals. Figure 4 The soft magnetic material includes nanocrystals as an example. When the soft magnetic material includes nanocrystals, the magnetic conductive sublayer 322 includes multiple layers of nanocrystals 3221 and multiple layers of adhesive glue 3222 for bonding the nanocrystals 3221 together and located on both sides of the nanocrystals 3221, wherein: Figure 4 The description is made by taking the magnetic conductive sublayer 322 including two layers of nanocrystals 3221 and three layers of adhesive 3222 as an example.

[0117] The thickness H21 of the protective sublayer 321 may be 5 μm, the thickness H22 of the nanocrystal 3221 may be 17 μm, and the thickness H23 of the adhesive 3222 may be 3 μm. In this case, the thickness H2 of the magnetic conductive layer 32 is 53 μm. Of course, the thickness of the protective sublayer 321, the thickness of the nanocrystal 3221, and / or the thickness of the adhesive 3222 may be adaptively changed to meet different requirements.

[0118] Continue to see Figure 4 The coil structure 31 may be an FPC coil, and the coil structure 31 includes two layers of protective films 311 and a functional layer 312 located between the two layers of protective films 311. The protective film 311 includes a PI layer 3111 and an adhesive 3112 for setting the PI layer 3111 on the functional layer 312. The functional layer 312 includes two layers of wiring sublayers 3121 and an insulating sublayer 3122 located between two adjacent layers of wiring sublayers 3121, and the two layers of wiring sublayers 3121 include a first wiring sublayer and a second wiring sublayer.

[0119] The wiring sublayer 3121 can be a whole-surface metal layer, wherein the material of the metal layer includes copper, aluminum, nickel or alloy, etc., and then a coil is formed by etching the metal layer. The specific circuit design of the formed coil will be introduced in detail below and will not be repeated here.

[0120] In order to realize the electrical connection between the two wiring sub-layers 3121, a via hole is provided on the insulating sub-layer 3122 between the two wiring sub-layers 3121, and a connection structure 3124 connecting the two wiring sub-layers 3121 is provided in the via hole. The formation method of the connection structure 3124 is not limited in the embodiment of the present application. Figure 4 , a whole connection layer 3123 may be plated on the wiring sub-layer 3121 , and during the plating process, part of the material of the connection layer 3123 may be deposited into the via hole to form the connection structure 3124 . For another example, the connection structure 3124 may be formed directly in the via hole of the insulating sub-layer 3122 .

[0121] Exemplarily, the thickness H11 of the PI layer 3111 may be 5 μm, the thickness H12 of the adhesive 3112 may be 5 μm, the thickness H13 of the insulating sublayer 3122 may be 12.5 μm, the thickness H14 of the wiring sublayer 3121 may be 12 μm, and the thickness H15 of the connecting layer 3123 may be 10 μm. In this case, the thickness H1 of the coil structure 31 is 76.5 μm. Alternatively, the thickness H11 of the PI layer 3111 may be 5 μm, the thickness H12 of the adhesive 3112 may be 5 μm, the thickness H13 of the insulating sublayer 3122 may be 12.5 μm, the thickness H14 of the wiring sublayer 3121 may be 18 μm, and the thickness H15 of the connecting layer 3123 may be 10 μm. In this case, the thickness H1 of the coil structure 31 is 88.5 μm.

[0122] In addition, the double-sided tape 33 between the coil structure 31 and the magnetic conductive layer 32 may be 7.5 μm.

[0123] See also Figure 5a-5d , Figure 5a This is a three-dimensional diagram of a coil module provided in Example 1 of the present application. Figure 5b for Figure 5a The plan view of the coil module shown, Figure 5b (1) is the front view. Figure 5b (2) is the back view. Figure 5c for Figure 5a The exploded view of the coil module shown, Figure 5d for Figure 5a The exploded view of the coil structure in the coil module shown in FIG. Figure 4 , Figure 5a-5d As shown, the coil structure 31 includes a first end D1, a second end D2 and N groups of coil groups 31a connected in series in sequence. The first end D1 and the second end D2 are connected by the N groups of coil groups 31a connected in series in sequence, wherein one group of coil groups 31a is one circle (i.e., one turn) of the coil structure 31.

[0124] The N coil groups 31a can be an annular coil, wherein the outer diameter d1 of the coil is less than or equal to 52mm and greater than or equal to 46mm; the inner diameter d2 of the coil is less than or equal to 28mm and less than or equal to 16mm. For example, the outer diameter d1 of the coil is 46mm, 47mm, 48mm, 49mm, 50mm, 51mm or 52mm; the inner diameter d2 of the coil is 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm or 28mm. It should be noted that the embodiments of the present application do not limit the specific form of the annular coil, and those skilled in the art can set it according to actual conditions. For example, the annular coil includes a circular annular coil, a rectangular annular coil, a hexagonal annular coil, an octagonal annular coil, etc., and the embodiments of the present application are all described by taking the annular coil as an example of a circular annular coil.

[0125] The first end D1 and the multiple coil groups 31a are formed by etching the first wiring sub-layer and the connection layer 3123 located on the first wiring sub-layer, and the second end D2 and the multiple coil groups 31a are formed by etching the second wiring sub-layer and the connection layer 3123 located on the second wiring sub-layer. The outermost coil group 31a of the N coil groups 31a is connected to the first end D1, and the innermost coil group 31a of the N coil groups 31a is connected to the second end D2 through the connection structure 3124 in the via hole in the insulating sub-layer 3122, so that the first end D1 is connected to the second end D2 through the multiple coil groups 31a connected in series.

[0126] Continue to see Figure 4 , Figure 5a-5d A hollow portion 32a is provided on the magnetic conductive layer 32, and the second end D2 of the coil structure 31 is embedded in the hollow portion 32a. In this way, the second end D2 can avoid occupying the coil module 30 in the thickness direction, thereby reducing the thickness of the coil module 30. For example, the thickness can be reduced to H11+H12+H14+H15=5+5+10+12=32μm; or the thickness can be reduced to H11+H12+H14+H15=5+5+10+18=38μm.

[0127] In order to further reduce the thickness of the coil module 30, continue to refer to Figure 4 A portion of the protective sublayer (i.e., the first protective sublayer) 321 in the magnetic conductive layer 32 that is in contact with the coil structure 31 is hollowed out, and the hollowing out can expose the adhesive 3222 between the protective sublayer 321 and the nanocrystal 3221. The double-sided tape 33 that bonds the coil structure 31 and the magnetic conductive layer 32 is located in the hollow portion 3211 and is in contact with the adhesive 3222 between the protective sublayer 321 and the nanocrystal 3221.

[0128] It is understandable that in order to ensure the bonding strength between the coil structure 31 and the magnetic conductive layer 32, the thickness of the double-sided adhesive tape 33 still needs to be maintained at 7.5 μm, so the thickness of the protective sublayer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 and the film layer where the double-sided adhesive tape 33 is located is 7.5 μm. In this way, the thickness of the coil module 30 can be reduced by 5 μm (the thickness of one protective sublayer 321).

[0129] Through the above configuration, the thickness of the coil module 30 can be 100 μm or 106 μm, that is, the thickness of the wireless charging coil module is made extremely thin, so that the coil module occupies less space inside the electronic device, which is conducive to the configuration of other structures.

[0130] In some embodiments, see Figure 4 , the adhesive 3222 disposed adjacent to the second protective sublayer is the first adhesive; the first protective sublayer, the other adhesives 3222 except the first adhesive, and the film layer where the nanocrystal 3221 is located are provided with a first opening 32a1, and the film layer where the first adhesive and the second protective sublayer are located are provided with a second opening 32a2, and the first opening and the second opening form a hollow portion 32a. The first opening 32a1 is larger than the second opening 32a2, that is, the projection of the second opening 32a2 on the second protective sublayer is located within the projection of the first opening 32a1 on the second protective sublayer.

[0131] In this way, the nanocrystalline powder can be prevented from falling out, making the structure of the coil module more reliable.

[0132] The above is an introduction to the film structure of the coil module 30. It can be seen from the above that the thickness of the coil module 30 of the present application can be only 0.1Xmm. It can be understood that when the thickness of the coil module is thin, the impedance of the coil module is generally large, and a large impedance is not conducive to high-power charging of the wireless charging receiving device. In order to achieve the effect of high-power charging and thinness of the wireless charging receiving device, continue Figure 5a-5d , the number N of coil groups 31a is less than or equal to 8 and greater than or equal to 7, that is, the number of turns of the coil structure 31 is 7 to 8 turns. For example, the number of turns of the coil structure 31 can be 7 turns (such as Figure 5c as shown) or 8 turns (as shown Figure 6 Of course, the number of turns of the coil structure 31 can also be 7.5 turns, and 0.5 turns is half a turn of the wire. Exemplarily, 7.5 turns can be formed by winding half a turn on the basis of the outermost coil group 31a among the 7 coil groups 31a, or by winding half a turn on the basis of the innermost coil group 31a among the 7 coil groups 31a.

[0133] When the number of turns of the coil structure 31 is 7 to 8 turns, the coil structure 31 can achieve both high-power and high-freedom wireless charging effects. The charging power will not be affected due to too many turns and high impedance, nor will the degree of freedom of the coil structure 31 be low due to too few turns. That is, when the coil module 30 is applied to the wireless charging receiving device 20, when the number of turns of the transmitting coil in the wireless charging transmitting device 10 is certain (such as 12 turns), the offset distance between the center of the receiving coil and the center of the transmitting coil is small, so strict alignment is required, which makes the degree of freedom of the coil structure 31 low.

[0134] In some embodiments, each coil group 31a includes M strands of wire 311a, where M may be less than or equal to 4 and greater than or equal to 2. For example, M is 2, 3 or 4. Figure 5c and Figure 6 The description is made by taking M as 3 as an example. That is, the coil structure 31 is continuously wound from the first end D1 by M strands of wire 311a (forming N coil groups 31a connected in series in sequence) to the second end D2, and is distributed in two layers of wiring sub-layers 3121. The current is input from the first end D1, passes through the N coil groups 31a, and is output from the second end D2.

[0135] By setting M to be less than or equal to 4 and greater than or equal to 2, there will be no waste of routing space due to a large gap between two adjacent wires 311a due to a large number of wires 311a, nor will there be fewer channels for current flow due to the skin effect due to a small number of wires 311a, thus affecting current transmission.

[0136] The number of strands of each coil group 31a can be determined based on the actual number of turns of the coil structure 31 and the thickness of the wiring sublayer 3121, so that the coil structure 31 can achieve both high-power and high-freedom wireless charging effects.

[0137] For a possible implementation, see Figure 7 , Figure 7 This is an exploded view of another coil module provided in Example 1 of the present application. Figure 7 As shown, the number of coil groups 31a is 7, the thickness of the first wiring sublayer is greater than or equal to 25μm and less than or equal to 40μ, and each coil group 31a includes M strands of wire 311a, where M is greater than or equal to 3, such as 4.

[0138] With this arrangement, even if the coil group 31 a is thick, it is possible to avoid a large eddy current loss being generated in the thick coil group 31 a.

[0139] It should be noted that, in the embodiment of the present application, when a connection layer 3123 is provided on the first wiring sub-layer, the thickness of the first wiring sub-layer also includes the thickness of the connection layer 3123 .

[0140] In another possible implementation, see Figure 5c The number of coil groups 31a is 7, the thickness of the first wiring sub-layer is less than or equal to 25 μm, and each coil group 31a includes M strands of wire 311a, where M is less than or equal to 4, such as M is 3.

[0141] Because the M strands of conductive wire 311a are formed by cutting and routing, when M is less than or equal to 4, it is possible to avoid wasting a lot of routing space, and also to ensure more flow channels, thus achieving a better flow effect.

[0142] In another possible implementation, see Figure 6 The number of coil groups is 8, the thickness of the first wiring sublayer is greater than or equal to 25 μm and less than or equal to 40 μm, and each coil group 31a includes M strands of wire 311a, where M is greater than or equal to 2, such as M is 3.

[0143] In this way, even if the thickness of the coil group 31a is relatively thick, it is possible to avoid generating large eddy current losses on the thicker coil group 31a, and the impedance will not be increased due to the increase in the number of coil groups.

[0144] In another possible implementation, see Figure 8 , Figure 8 This is an exploded view of another coil module provided in Example 1 of the present application. Figure 8 As shown, the number of coil groups 31a is 8, the thickness of the first wiring sub-layer is less than or equal to 25 μm, and each coil group 31a includes M strands of wire 311a, where M is less than or equal to 3, such as 3.

[0145] Because the M strands of wire 311a are formed by cutting and routing, when M is less than or equal to 3, it can avoid wasting a lot of routing space and can also have a better current flow effect. And it will not have a larger impedance due to the increase in the number of coil groups.

[0146] In some embodiments, see Figure 5c The N groups of coil groups 31a include L groups of internal coil groups 31a-I and (NL) groups of external coil groups 31a-O arranged around the L groups of internal coil groups; each group of coil groups 31a includes multiple strands of wire 311a; the number of wire strands located in the external coil group 31a-O is greater than the number of wire strands located in the internal coil group 31a-I.

[0147] Since the magnetic field strength inside the coil structure 31 is relatively strong and the magnetic field strength outside is relatively weak, the number of wire strands located in the external coil group 31a-O is set to be greater than the number of wire strands located in the internal coil group 31a-I, which can ensure that the external coil group 31a-O has more current passages and improve the uniformity of current distribution.

[0148] The specific value of L is not limited in the embodiment of the present application, and those skilled in the art can set it according to actual conditions. For example, N is 7, L is 3: the number of coil groups 31a is 7, and the coil groups from the innermost circle to the outermost circle are the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group. The 7 coil groups 31a include 3 internal coil groups 31a-I and 4 external coil groups 31a-O arranged around the 3 internal coil groups, that is, the first coil group, the second coil group, and the third coil group are the internal coil groups 31a-I, the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group are the external coil groups 31a-O, the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group have the same number of wire strands, the first coil group, the second coil group, and the third coil group have the same number of wire strands, and the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group have more wire strands than the first coil group, the second coil group, and the third coil group.

[0149] In some embodiments, see Figure 6 , in the direction away from the center of the coil structure, such as Figure 6 In the direction indicated by arrow XX, the width W0 of the plurality of coil groups 31 a gradually increases.

[0150] The width of the multiple coil groups 31a gradually increases, which can be: along the direction away from the center of the coil structure, the width of the multiple coil groups 31a gradually increases in sequence, such as, the number of coil groups 31a is 8, and the coil groups 31a from the innermost circle to the outermost circle are divided into the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The widths of the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group increase in sequence, that is, the width of the eighth coil group is greater than the width of the seventh coil group, the width of the seventh coil group is greater than the width of the sixth coil group, the width of the sixth coil group is greater than the width of the fifth coil group, the width of the fifth coil group is greater than the width of the fourth coil group, the width of the fourth coil group is greater than the width of the third coil group, the width of the third coil group is greater than the width of the second coil group, and the width of the second coil group is greater than the width of the first coil group.

[0151] The width of the multiple coil groups 31a can also be gradually increased: along the direction away from the center of the coil structure, the widths of some adjacent coil groups 31a are the same, and the widths of the coil groups 31a with different widths gradually increase. For example, the number of coil groups 31a is 8, and the coil groups 31a from the innermost circle to the outermost circle are divided into the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group. The widths of the first coil group and the second coil group are the same, the widths of the third coil group, the fourth coil group, and the fifth coil group are the same, and the widths of the sixth coil group, the seventh coil group, and the eighth coil group are the same, and the widths of the first coil group, the third coil group, and the sixth coil group increase in sequence.

[0152] Since the magnetic field strength inside the coil structure 31 is relatively strong and the magnetic field strength outside is relatively weak, the width of the innermost coil group 31a, the width of the middle coil group 31a, and the width of the outermost coil group 31a are set to increase in sequence, so that the current carrying capacity of the innermost coil group 31a, the middle coil group 31a, and the outermost coil group 31a can be gradually enhanced, thereby improving the uniformity of current distribution.

[0153] It should be noted here that, when the width W0 of the multiple coil groups 31a gradually increases in the direction away from the center of the coil structure, the number of strands of the wire 311a of each coil group 31a can be the same, such as 3 strands or 4 strands; of course, the number of strands of the wire 311a of each coil group 31a can also be different.

[0154] To facilitate understanding of the above content, the specific structure of the coil module 30 provided in the embodiment of the present application is introduced below in combination with specific examples.

[0155] Example 1, continue to see Figure 4 and 7 , the inner diameter d1 of the coil is 20 mm, the outer diameter d2 of the coil is 48 mm, N is 7, and M is 4, that is, in the limited area defined by the outer diameter d2 of the coil being 48 mm and the inner diameter d1 of the coil being 20 mm, the coil structure 31 adopts a 7-turn 4-strand parallel winding scheme; the magnetic conductive sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17 μm), and the material properties of the nanocrystals satisfy: the saturation magnetic flux density of the nanocrystals is 1.4 T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e. μ'3000).

[0156] The electrical parameters in this example are shown in Table 1. In Table 1, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0157] Table 1

[0158]

[0159]

[0160] It can be seen from Table 1 that under different electromagnetic wave frequencies, the inductance L of the coil module will also change. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 8.9253Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.), and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at a very small thickness (e.g., a thickness of 0.110mm), which is conducive to high-power wireless charging.

[0161] In addition, the 7 coil groups 31a are divided into the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group from the inside to the outside. The widths of the third coil group, the fourth coil group, and the fifth coil group are the same, the widths of the sixth coil group and the seventh coil group are the same, and the widths of the first coil group, the second coil group, the third coil group, and the sixth coil group gradually increase. The circuit design of the 7 coil groups 31a is specifically shown in Table 2. Among them, the line spacing of the 4 strands of wire 311a of each coil group 31a is 0.06mm. It can be understood that the line spacing is related to the process level, and the smaller the line spacing, the better.

[0162] Table 2

[0163]

[0164]

[0165] The coil module in this example was tested for current density distribution. The test results are as follows: Fig. 9 As shown, Fig. 9 (1) is the current density distribution of the coil module 30. The color corresponding to each position in the coil module 30 represents the current value. Fig. 9 (2) in the figure is the corresponding relationship between color and current value, that is, Fig. 9 The colors of each position in (1) are Fig. 9 The corresponding relationship between the color and the current value provided by (2) in the formula is determined Fig. 9 The current value at each position in (1).

[0166] like Fig. 9As shown, through the current density distribution test results, it is found that the colors corresponding to each position in the coil module 30 are relatively uniform, and the differences in the colors corresponding to each position are small, that is, the colors corresponding to each position have good consistency. It can be seen that with the coil module in this example, there is current at each position, and the current density is relatively uniform in steps, which is conducive to high-power wireless charging.

[0167] In summary, the coil module provided in this example can enable the wireless charging receiving device to have both high-power charging and lightweight effects.

[0168] In order to better illustrate this effect, a simulation test was carried out on the coil module provided in the embodiment of the present application, and the simulation test results are shown in Table 3, wherein the offset in Table 3 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and the positive and negative values ​​can respectively represent that the center of the receiving coil is offset to the left and to the right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and the input current are the voltage and the current provided by the wireless charging sending device side; the output voltage and the output current are the voltage and the current generated by the wireless charging receiving device side based on the voltage and the current provided by the wired charging sending device side; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0169] Table 3 Charging efficiency under different offsets

[0170]

[0171]

[0172] It can be seen from Table 3 that the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0173] Example 2, continue to see Figure 4 and 5c , the inner diameter d1 of the coil is 20 mm, the outer diameter d2 of the coil is 48 mm, N is 7, and M is 3, that is, in the limited area defined by the outer diameter d2 of the coil being 48 mm and the inner diameter d1 of the coil being 20 mm, the coil structure 31 adopts a 7-turn 3-strand parallel winding scheme; the magnetic conductive sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17 μm), and the material properties of the nanocrystals satisfy: the saturation magnetic flux density of the nanocrystals is 1.4 T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e. μ'3000).

[0174] The electrical parameters in this example are shown in Table 4. In Table 4, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0175] Table 4

[0176]

[0177] It can be seen from Table 4 that under different electromagnetic wave frequencies, the inductance L of the coil module will also change. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 7.8173Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.), and will not affect wireless charging. In other words, the coil module provided in this example also has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.102mm).

[0178] The 7 coil groups 31a are divided into the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, and the seventh coil group from the inside to the outside. The widths of the first coil group and the second coil group are the same, the widths of the fifth coil group and the sixth coil group are the same, and the widths of the first coil group, the third coil group, the fourth coil group, the fifth coil group, and the seventh coil group gradually increase. The circuit design of the 7 coil groups 31a is specifically shown in Table 5. Among them, the line spacing of the three strands of wire 311a of each coil group 31a is 0.06mm. It can be understood that the line spacing is related to the process level, and the smaller the line spacing, the better.

[0179] Table 5

[0180]

[0181]

[0182] The coil module in this example was tested for current density distribution. The test results are as follows: Fig.10 As shown, Fig.10 (1) is the current density distribution of the coil module 30. The color corresponding to each position in the coil module 30 represents the current value. Fig.10 (2) in the figure is the corresponding relationship between color and current value, that is, Fig.10 The colors of each position in (1) are Fig.10 The corresponding relationship between the color and the current value provided by (2) in the formula is determined Fig.10 The current value at each position in (1).

[0183] like Fig.10As shown, through the current density distribution test results, it is found that the colors corresponding to each position in the coil module 30 are relatively uniform, and the differences in the colors corresponding to each position are small, that is, the colors corresponding to each position have good consistency. It can be seen that with the coil module in this example, there is current at each position, and the current density is relatively uniform in steps, which is conducive to high-power wireless charging.

[0184] In summary, the coil module provided in this example can enable the wireless charging receiving device to have both high-power charging and lightweight effects.

[0185] In order to better illustrate this effect, a simulation test was carried out on the coil module provided in the embodiment of the present application, and the simulation test results are shown in Table 6, wherein the offset in Table 6 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and the positive and negative values ​​can respectively represent that the center of the receiving coil is offset to the left and to the right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and input current are the voltage and current provided by the wireless charging sending device side; the output voltage and output current are the voltage and current generated by the wireless charging receiving device side based on the voltage and current provided by the wired charging sending device side; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0186] Table 6 Charging efficiency under different offsets

[0187]

[0188]

[0189] It can be seen from Table 6 that the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0190] Example 3, continue to see Figure 4 and 6 , the inner diameter d1 of the coil is 20 mm, the outer diameter d2 of the coil is 48 mm, N is 8, and M is 3, that is, in the limited area defined by the outer diameter d2 of the coil being 48 mm and the inner diameter d1 of the coil being 20 mm, the coil structure 31 adopts an 8-turn 3-strand parallel winding scheme; the magnetic conductive sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17 μm), and the material properties of the nanocrystals satisfy: the saturation magnetic flux density of the nanocrystals is 1.4 T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e. μ'3000).

[0191] The electrical parameters in this example are shown in Table 7. In Table 7, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0192] Table 7

[0193]

[0194] It can be seen from Table 7 that under different electromagnetic wave frequencies, the inductance L of the coil module will also change. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 7.8172Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.), and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.109mm), which is conducive to high-power wireless charging.

[0195] The 8 coil groups 31a are divided into the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group from the inside to the outside. The widths of the first coil group, the second coil group, the third coil group, and the fourth coil group are the same, the widths of the fifth coil group, the sixth coil group, and the seventh coil group are the same, and the widths of the first coil group, the fifth coil group, and the eighth coil group gradually increase. The circuit design of the 8 coil groups 31a is specifically shown in Table 8. Among them, the line spacing of the three strands of wire 311a of each coil group 31a is 0.06mm. It can be understood that the line spacing is related to the process level, and the smaller the line spacing, the better.

[0196] Table 8

[0197]

[0198] The coil module in this example was tested for current density distribution. The test results are as follows: Fig.11 As shown, Fig.11 (1) is the current density distribution of the coil module 30. The color corresponding to each position in the coil module 30 represents the current value. Fig.11 (2) in the figure is the corresponding relationship between color and current value, that is, Fig.11 The colors of each position in (1) are Fig.11 The corresponding relationship between the color and the current value provided by (2) in the formula is determined Fig.11 The current value at each position in (1).

[0199] like Fig.11As shown, through the current density distribution test results, it is found that the colors corresponding to each position in the coil module 30 are relatively uniform, and the differences in the colors corresponding to each position are small, that is, the colors corresponding to each position have good consistency. It can be seen that with the coil module in this example, there is current at each position, and the current density is relatively uniform in steps, which is conducive to high-power wireless charging.

[0200] In summary, the coil module provided in this example can enable the wireless charging receiving device to have both high-power charging and lightweight effects.

[0201] In order to better illustrate this effect, a simulation test was carried out on the coil module provided in the embodiment of the present application, and the simulation test results are shown in Table 9, wherein the offset in Table 9 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and the positive and negative values ​​may respectively represent that the center of the receiving coil is offset to the left and to the right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and the input current are the voltage and the current provided by the wireless charging sending device side; the output voltage and the output current are the voltage and the current generated by the wireless charging receiving device side based on the voltage and the current provided by the wireless charging sending device side; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0202] Table 9 Charging efficiency under different offsets

[0203]

[0204] It can be seen from Table 9 that the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0205] Example 4, continue to see Figure 4 and 8 , the inner diameter d1 of the coil is 20mm, the outer diameter d2 of the coil is 48mm, N is 8, and M is 3, that is, in the limited area defined by the outer diameter d2 of the coil being 48mm and the inner diameter d1 of the coil being 20mm, the coil structure 31 adopts an 8-turn 3-strand parallel winding scheme; the magnetic permeability sublayer 322 includes two layers of nanocrystals 3221 (the thickness of each layer of nanocrystals 3221 is 17μm), and the material properties of the nanocrystals satisfy: the saturation magnetic flux density of the nanocrystals is 1.4T, and the relative magnetic permeability of the nanocrystals is 3000 times that of air (i.e. μ'3000). It should be noted that the thickness of the wiring sublayers of Example 1 and Example 3 is the same, for example, both are 18μm, the thickness of the wiring sublayers of Example 2 and Example 4 is the same, for example, both are 12μm, and the thickness of other film layers of Example 1, Example 2, Example 3 and Example 4 are the same.

[0206] The electrical parameters in this example are shown in Table 10. In Table 10, L is the inductance of the coil module, Q is the quality factor of the coil module, ARC is the AC impedance of the coil module, and DRC is the DC impedance of the coil module.

[0207] Table 10

[0208]

[0209]

[0210] It can be seen from Table 10 that under different electromagnetic wave frequencies, the inductance L of the coil module will also change. And as the frequency increases, the AC impedance ARC increases, but the AC impedance ARC and the DC impedance DRC are both small. And the coil module of this example has a good quality factor Q. In addition, the self-resonant frequency of the coil module of this example is 7.8172Mhz, which is far from the operating frequency of the coil module (100KHZ, 130KHZ or 145KHZ, etc.), and will not affect wireless charging. In other words, the coil module provided in this example has a small impedance and a more suitable inductance at an extremely small thickness (e.g., a thickness of 0.109mm), which is conducive to high-power wireless charging.

[0211] The 8 coil groups 31a are divided into the first coil group, the second coil group, the third coil group, the fourth coil group, the fifth coil group, the sixth coil group, the seventh coil group, and the eighth coil group from the inside to the outside. The widths of the first coil group, the second coil group, the third coil group, and the fourth coil group are the same, the widths of the fifth coil group, the sixth coil group, and the seventh coil group are the same, and the widths of the first coil group, the fifth coil group, and the eighth coil group gradually increase. The circuit design of the 8 coil groups 31a is specifically shown in Table 11. Among them, the line spacing of the three strands of wire 311a of each coil group 31a is 0.06mm. It can be understood that the line spacing is related to the process level, and the smaller the line spacing, the better.

[0212] Table 11

[0213]

[0214] In summary, the coil module provided in this example can enable the wireless charging receiving device to have both high-power charging and lightweight effects.

[0215] In order to better illustrate this effect, a simulation test was carried out on the coil module provided in the embodiment of the present application, and the simulation test results are shown in Table 12, wherein the offset in Table 12 is the offset distance between the center of the transmitting coil and the center of the receiving coil, and the positive and negative values ​​may respectively represent that the center of the receiving coil is offset to the left and to the right relative to the center of the transmitting coil; the target power is the charging efficiency under different loads; the input voltage and input current are the voltage and current provided by the wireless charging sending device side; the output voltage and output current are the voltage and current generated by the wireless charging receiving device side based on the voltage and current provided by the wireless charging sending device side; the input power is the product of the input voltage and the input current; the output power is the product of the output voltage and the output current; and the efficiency is the ratio of the output power to the input power.

[0216] Table 12 Charging efficiency at different offsets

[0217]

[0218] It can be seen from Table 12 that the ultra-thin coil module provided in the embodiment of the present application can also support 30W high-power wireless charging.

[0219] It can be seen from the above four examples that the ultra-thin coil module provided in this application can also support 30W high-power wireless charging.

[0220] Embodiment 2

[0221] See also Fig.12 , Fig.13 and Fig.14 , Fig.12 A film layer diagram of a coil module provided in Example 2 of the present application, Fig.13 This is a plan view of a coil module provided in Example 2 of the present application. Fig.14 for Fig.13 The exploded view of the coil module is shown in Figure 1. Fig.12 , Fig.13 and Fig.14 As shown, different from the first embodiment, the magnetic conductive layer 32 in the second embodiment is located on one side of the coil structure 31, and the magnetic conductive layer 32 is not provided with a hollow portion 32a, and accordingly, the second wiring sublayer provided with the second end D2 of the coil structure 31 is located between the first wiring sublayer and the magnetic conductive layer 32. In this embodiment, the coil structure 31 further includes at least one flexible circuit board unit 31b, and the flexible circuit board unit 31b and the second end D2 of the coil structure 31 are both located in the second wiring sublayer, wherein the flexible circuit board unit 31b is located in a preset area of ​​the second wiring sublayer, and the preset area is an area of ​​the second wiring sublayer where the second end D2 is not provided.

[0222] It should be noted that, unless otherwise specified, the specific structure of the coil module 30 in the embodiment of the present application (such as the thickness of each film layer, the number of groups, the number of strands and the width design of the coil group 31a, etc.) is the same as that in Example 1. Please refer to Example 1 for details and will not be repeated here.

[0223] That is to say, when the coil module is provided in an electronic device, the flexible circuit board in the electronic device can be provided in the second wiring sublayer, that is, the coil module includes both the wireless charging coil and the flexible circuit board in the electronic device. In this way, the occupation of the internal space of the electronic device by other flexible circuit boards is avoided, which is conducive to the setting of other structures and can also reduce the process steps.

[0224] As can be seen from the above content, the main board 2041 and the sub-board 2042 can be connected through the FPC. Therefore, in one example, the FPC unit connecting the main board 2041 and the sub-board 2042 can be set in the preset area of ​​the second wiring sub-layer, so that there is no need to separately set the FPC connecting the main board 2041 and the sub-board 2042 in the accommodating cavity of the electronic device, avoiding the occupation of the internal space of the electronic device by the FPC, which is conducive to the arrangement of other structures, and the FPC is formed at the same time as the second end D2 is formed, reducing the process steps.

[0225] Since the NFC coil can be wound by FPC wiring, in another example, the NFC coil can be arranged in a preset area of ​​the second wiring sublayer, so that there is no need to separately arrange the NFC coil in the accommodating cavity of the electronic device, so as to avoid the NFC coil occupying the internal space of the electronic device, which is conducive to the arrangement of other structures, and the NFC coil is formed at the same time as the second end D2 is formed, thereby reducing the process steps.

[0226] In addition, functional devices such as the wireless charging coil (such as the receiving coil L2), speakers, and SIM cards are all connected to the main board 2041 or the sub-board 2042 through the FPC. Therefore, in another example, the FPC connecting the functional devices and the main board 2041 or the sub-board 2042 can be set in a preset area of ​​the second wiring sublayer. In this way, there is no need to separately set the FPC connecting the functional devices and the main board 2041 or the sub-board 2042 in the accommodating cavity of the electronic device, thereby avoiding the FPC from occupying the internal space of the electronic device, which is beneficial to the arrangement of other structures, and the FPC is formed at the same time as the second end D2 is formed, thereby reducing the process steps.

[0227] It should be noted that the above examples are only used as an example to illustrate that the FPC connecting the main board 2041 and the sub-board 2042, the NFC coil or the connection functional device (such as a wireless charging coil, a speaker, a SIM card, etc.) and the line of the FPC of the main board 2041 or the sub-board 2042 are arranged in the second wiring sublayer, but it does not constitute a limitation of the present application. Under the condition that the working requirements of each functional device are met, other FPCs in the electronic device can be arranged in the preset area of ​​the second wiring sublayer.

[0228] In some embodiments, the preset area includes a first sub-area YY, and the first sub-area YY is an area formed by the projection of the outermost coil group on the second wiring sub-layer extending by a first preset length W1 in all directions (ie, Fig.13 When the line width W2 of the flexible circuit board unit 31b in the first sub-area YY is greater than the second preset length, the routing of the flexible circuit board unit 31b in the first sub-area YY is cut into multiple lines. That is, the wider routing of the flexible circuit board unit 31b in the first sub-area YY is cut into multiple thin lines, which can avoid excessive eddy current loss on the wider routing.

[0229] For example, the first preset length may be 5 mm, and the second preset length may be 8 mm. That is to say, at least within the 5 mm range of the maximum extension of the coil shape, avoid having a line width greater than 8 mm. Wider lines within this range can be cut into strands, and the thinner the line width is, the better.

[0230] It can be seen from the above two embodiments that multiple coil groups with larger occupied areas are arranged in the first wire sub-layer, and the second wiring sub-layer only includes the second end with smaller occupied area. In this way, when the coil module is arranged in the electronic device, other wirings of the electronic device can be arranged on the second wiring sub-layer to avoid other wirings occupying the internal space of the electronic device, which is conducive to the arrangement of other structures. Alternatively, since the second wiring sub-layer only has the second end with smaller occupied area, the second end with smaller occupied area can be embedded in other structures, so that the coil module occupies less space inside the electronic device, which is conducive to the arrangement of other structures.

[0231] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A coil module, characterized in that: include: Coil structure; The coil structure comprises a functional layer, and along a thickness direction of the coil structure, the functional layer comprises a first wiring sub-layer, a second wiring sub-layer, and an insulating sub-layer located between the first wiring sub-layer and the second wiring sub-layer; The coil structure comprises a first end, a second end and a plurality of coil groups connected in series in sequence, the first end and the plurality of coil groups are arranged in the first wiring sub-layer, and the outermost coil group is connected to the first end; The second end is arranged on the second wiring sublayer; a via is opened on the insulating sublayer, and a connecting structure is arranged in the via; the innermost coil group is connected to the second end through the connecting structure in the insulating sublayer, so that the first end is electrically connected to the second end through multiple coil groups connected in series in sequence.

2. The coil module according to claim 1, characterized in that: The coil module further includes: a magnetic conductive layer; the magnetic conductive layer includes a hollow portion, and the second end is arranged in the hollow portion.

3. The coil module according to claim 2, characterized in that: Along the thickness direction of the coil structure, the magnetic conductive layer includes a first protective sublayer, a second protective sublayer and a magnetic conductive sublayer located between the first protective sublayer and the second protective sublayer, and the magnetic conductive sublayer includes multiple layers of adhesive and nanocrystals located between two adjacent layers of the adhesive; The first protective sublayer is disposed adjacent to the coil structure, and the adhesive disposed adjacent to the second protective sublayer is a first adhesive; The first protective sublayer, the other adhesives except the first adhesive, and the film layer where the nanocrystals are located are provided with a first opening, the film layer where the first adhesive and the second protective sublayer are located are provided with a second opening, and the first opening and the second opening form the hollow portion; The projection of the second opening on the reference plane is located within the projection of the first opening on the reference plane, and the reference plane is perpendicular to the thickness direction of the coil structure.

4. The coil module according to claim 3, characterized in that: The thickness of the coil module is less than 0.2 mm.

5. The coil module according to claim 1, characterized in that: The coil structure further includes a flexible circuit board unit; the flexible circuit board unit is located in a preset area of ​​the second wiring sub-layer, and the preset area is an area of ​​the second wiring sub-layer where the second end is not provided.

6. The coil module according to claim 5, characterized in that: The preset area includes a first sub-area, and the first sub-area is an area formed by extending the projection of the outermost coil group on the second wiring sub-layer by a first preset length in all directions; When the line width of the flexible circuit board unit in the first sub-area is greater than the second preset length, the routing line of the flexible circuit board unit in the first sub-area is cut into multiple lines.

7. The coil module according to claim 5, characterized in that: The coil module further includes: a magnetic conductive layer; along the thickness direction of the coil structure, the magnetic conductive layer is located on a side of the second wiring sub-layer away from the first wiring sub-layer.

8. The coil module according to any one of claims 1 to 7, characterized in that: The number of the coil groups is N, where N is less than or equal to 8 and greater than or equal to 7.

9. The coil module according to claim 8, characterized in that: The number of the coil groups is 7, the thickness of the first wiring sublayer is greater than or equal to 25 μm and less than or equal to 40 μm, and each coil group includes M strands of wire, where M is greater than or equal to 3.

10. The coil module according to claim 9, characterized in that: M is 4.

11. The coil module according to claim 8, characterized in that: The number of the coil groups is 7, the thickness of the first wiring sub-layer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 4.

12. The coil module according to claim 11, characterized in that: M is 3.

13. The coil module according to claim 8, characterized in that: The number of the coil groups is 8, the thickness of the first wiring sublayer is greater than or equal to 25 μm and less than or equal to 40 μm, and each coil group includes M strands of wire, where M is greater than or equal to 2.

14. The coil module according to claim 13, characterized in that: M is 3.

15. The coil module according to claim 8, characterized in that: The number of the coil groups is 8, the thickness of the first wiring sub-layer is less than or equal to 25 μm, and each coil group includes M strands of wire, where M is less than or equal to 3.

16. The coil module according to claim 15, characterized in that: M is 3.

17. The coil module according to any one of claims 1 to 16, characterized in that: Along the direction away from the center of the coil structure, the widths of the plurality of coil groups gradually increase.

18. The coil module according to any one of claims 1 to 16, characterized in that: The number of coil groups is N, and the N coil groups include L internal coil groups and (NL) external coil groups arranged around the L internal coil groups; Each of the coil groups includes a plurality of wire strands; The number of wire strands located in the outer coil group is greater than the number of wire strands located in the inner coil group.

19. The coil module according to any one of claims 1 to 18, characterized in that: The coil structure is an FPC coil.

20. An electronic device, characterized in that: It comprises a coil module as described in any one of claims 1-19.

21. The electronic device according to claim 20, characterized in that: The coil structure further includes at least one flexible circuit board unit; the flexible circuit board unit is located in a preset area of ​​the second wiring sublayer, and the preset area is an area of ​​the second wiring sublayer where the second end is not provided; The electronic device further includes a printed circuit board, and the flexible circuit board unit is connected to the printed circuit board.

22. The electronic device according to claim 21, characterized in that: The printed circuit board includes a main board and a sub-board, and the main board is connected to the sub-board through the flexible circuit board unit.

23. The electronic device according to claim 21, characterized in that: The electronic device further includes a functional device, and the functional device is connected to the printed circuit board through the flexible circuit board unit.

24. The electronic device according to claim 23, characterized in that: The functional device includes a speaker or a SIM card.

25. The electronic device according to claim 21, characterized in that: The flexible circuit board unit is configured as an NFC coil.

26. The electronic device according to any one of claims 20 to 25, characterized in that: The electronic device includes a wireless charging receiving device or a wireless charging sending device.

27. A wireless charging system, characterized in that: include: An electronic device as claimed in any one of claims 20 to 26.

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