Coil module, wireless charging receiving device, and wireless charging system

Abstract

A coil module, a wireless charging receiving device (20), and a wireless charging system (01), which relate to the technical field of wireless charging, and can simultaneously take into account the effects of lightness and thickness, high power, and high-degree-of-freedom wireless charging. The coil module operates in a magnetically-coupled wireless charging system (01) with a frequency less than or equal to 500 kHz; the coil module comprises a coil structure (31), which coil structure (31) is a toroidal coil, wherein the thickness of the coil structure (31) is less than or equal to 0.175 mm and is greater than or equal to 0.07 mm, the outer diameter of a coil of the coil structure (31) is less than or equal to 52 mm and greater than or equal to 46 mm, and the inner diameter of the coil of the coil structure (31) is less than or equal to 28 mm and greater than or equal to 16 mm; and the inductance of the coil module is less than or equal to 6 μH and is greater than or equal to 4 μH.

Description

Coil module, wireless charging receiving device and wireless charging system

[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 202410047064.0 and application name “Coil module, wireless charging receiving device and wireless charging system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of wireless charging technology, and in particular to a coil module, a wireless charging receiving 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.

[0004] Existing wireless charging technology generally uses the principle of electromagnetic coupling to achieve power transmission. That is, the alternating current carried by the transmitting coil on the charging side generates a changing magnetic field, and the receiving coil on the side to be charged generates an induced current in the changing magnetic field, thereby achieving charging of the side to be charged.

[0005] However, as electronic devices become increasingly thinner and lighter, the space occupied by the receiving coil inside the electronic device is getting smaller and smaller. Ensuring high charging efficiency in the shrinking space is a technical problem that needs to be solved urgently. Summary of the Invention

[0006] In order to solve the above technical problems, the present application provides a coil module, a wireless charging receiving device and a wireless charging system, which can provide users with a high-power, high-freedom wireless charging experience as electronic devices become increasingly thinner and lighter.

[0007] In a first aspect, an embodiment of the present application provides a coil module, which operates in a magnetically coupled wireless charging system with a frequency less than or equal to 500 kHz, and the coil module includes: a coil structure; the coil structure is a ring coil; the thickness of the coil structure is less than or equal to 0.175 mm and greater than or equal to 0.07 mm; the outer diameter of the coil structure is less than or equal to 52 mm and greater than or equal to 46 mm, and the inner diameter of the coil structure is less than or equal to 28 mm and less than or equal to 16 mm; the inductance of the coil module is less than or equal to 6 μH and greater than or equal to 4 μH.

[0008] In this application, the outer diameter d1 of the coil structure is set to be less than or equal to 52 mm and greater than or equal to 46 mm; the inner diameter d2 of the coil is less than or equal to 28 mm and less than or equal to 16 mm. When the coil is thinned (the thickness of the coil structure is less than or equal to 0.175 mm and greater than or equal to 0.07 mm), the sum of the coil loss and the metal eddy current loss in the wireless charging receiving device is minimized, that is, the overall heat of the wireless charging receiving device is minimized, and accordingly, the loss is minimized, thereby enabling the coil structure to achieve the effects of lightweight, high-power and high-freedom wireless charging.

[0009] Exemplarily, the inductance of the coil module is less than or equal to 5.2 μH and greater than or equal to 4.2 μH, for example, 5.2 μH, 5.1 μH, 5.0 μH, 4.9 μH, 4.8 μH, 4.7 μH, 4.6 μH, 4.5 μH, 4.4 μH, 4.3 μH, or 4.2 μH.

[0010] Exemplarily, the outer diameter of the coil of the coil structure is 50 mm, and the inner diameter of the coil of the coil structure is 20 mm.

[0011] According to the first aspect, the coil structure includes a functional layer. Along the thickness direction of the coil structure, the functional layer includes a first wiring sublayer and a second wiring sublayer. The functional layer also includes an insulating sublayer located between the first wiring sublayer and the second wiring sublayer; a via is opened on the insulating sublayer, and a connection structure is provided in the via for electrically connecting the first wiring sublayer and the second wiring sublayer.

[0012] In this way, some coil groups in the coil structure can be routed on both sides. Under the premise of thin thickness, the current density in some coil groups can be dispersed in two layers, thereby improving the uniformity of current distribution.

[0013] According to the first aspect, or any implementation of the first aspect above, the coil structure includes N groups of coil groups; the N groups of coil groups include L groups of internal coil groups, wherein N is less than or equal to 8.5 and greater than or equal to 7.5; L is less than or equal to N; the L groups of internal coil groups are wound sequentially along the radial direction, and the first wiring sublayer and the second wiring sublayer are both wound with L groups of internal coil groups, and the L groups of internal coil groups of the first wiring sublayer and the L groups of internal coil groups of the second wiring sublayer are respectively electrically connected.

[0014] Since the magnetic field strength inside the coil structure is strong and the current density is unevenly distributed, the internal coil group is set to double-sided routing, so that the current density in the internal coil group can be dispersed in two layers, thereby improving the uniformity of current distribution.

[0015] According to the first aspect, or any implementation of the first aspect above, when L is less than N, the N groups of coil groups also include (NL) groups of external coil groups arranged around the L groups of internal coil groups; (NL) / 2 groups of external coil groups in the (NL) groups of external coil groups are wound on the first wiring sublayer and connected in series with the L groups of internal coil groups in the first wiring sublayer, and the remaining (NL) / 2 groups of external coil groups are wound on the second wiring sublayer and connected in series with the L groups of internal coil groups in the second wiring sublayer, so that the N groups of coil groups are connected in series in sequence.

[0016] When L is less than N, the (NL) external coil groups are connected in series, eliminating the need for conductive structures between the upper and lower layers, simplifying the coil structure's winding process. Furthermore, the coil structure of the present application utilizes a method in which each of the L internal coil groups near the center is wound in parallel on two wiring sublayers, while each of the (NL) external coil groups away from the center is wound in series on a single layer. This allows the coil structure to have a low impedance when its thickness is less than or equal to 0.2 mm.

[0017] According to the first aspect, or any implementation of the first aspect above, N is 8. The number of turns of the coil structure 31 is 8. When the coil is thinned, the sum of the coil loss and the metal eddy current loss in the wireless charging receiving device is minimized. That is, the overall heat of the wireless charging receiving device is minimized, and accordingly, the loss is minimized, thereby enabling the coil structure to achieve both high-power and high-freedom wireless charging effects.

[0018] According to the first aspect, or any implementation of the first aspect above, L is 2, 4, 6 or 8.

[0019] According to the first aspect, or any implementation of the first aspect, each coil group includes M strands of wire, where M may be less than or equal to 5 and greater than or equal to 3.

[0020] Each strand of wire in the coil structure is routed independently, and the wires of multiple coil groups on a single layer have the same number of strands and are connected in sequence, avoiding the problem of eddy current loss caused by the need to merge two wires and connect them to an adjacent wire when the number of strands of wire in different coil groups is different. In addition, M can be set to be less than or equal to 5 and greater than or equal to 3 because the outer diameter of the coil of the annular coil is less than or equal to 52mm and greater than or equal to 46mm; the inner diameter of the coil is less than or equal to 28mm and less than or equal to 16mm, that is, the area for setting wire 311a is limited. In a limited area, the impedance of the wiring sub-layer will not increase due to the large number of wire strands, resulting in a large gap between two adjacent wires, nor will the transmission of current be affected due to the skin effect, resulting in fewer channels for flow due to the small number of wire strands.

[0021] According to the first aspect, or any implementation of the first aspect, in the internal coil assembly, along the radial direction, the width of each wire is less than or equal to 0.6 mm and greater than or equal to 0.3 mm.

[0022] The magnetic field strength inside the coil structure is strong, and the current density is unevenly distributed. When the width of each wire in the coil group within group L is less than or equal to 0.6mm and greater than or equal to 0.3mm, eddy current losses are low, further improving charging performance.

[0023] According to the first aspect, or any implementation of the first aspect, the radial arrangement order of the M strands of wire of at least one coil group among the L groups of internal coil groups is changed.

[0024] The radial arrangement of the wires within the coil assembly is altered so that wires closer to the center of the coil structure move outward, while those farther from the center move inward. Within the same internal coil assembly, the current density is higher in the radially opposite wires, while the current density is lower in the center wire. By varying the radial position of the wires, the current density within the wires is varied, improving the uniformity of current distribution across the multiple wires within the internal coil assembly.

[0025] According to the first aspect, or any implementation of the first aspect above, M is 3; the three strands of wire are respectively a first wire, a second wire and a third wire; radially, the first wire and the third wire are located on both sides of the second wire; the coil structure includes a preset crossing area, the first wire of the first wiring sublayer and the third wire of the second wiring sublayer cross in the preset crossing area, and the first wire of the second wiring sublayer is disconnected at the preset crossing area, and the third wire of the first wiring sublayer is disconnected at the preset crossing area, the second wire of the first wiring sublayer and the second wire of the second wiring sublayer are disconnected in the preset crossing area, and the disconnected part of the second wire of the first wiring sublayer overlaps with the disconnected part of the second wire of the second wiring sublayer on the reference plane, and the disconnected part of the second wire of the first wiring sublayer and the disconnected part of the second wire of the second wiring sublayer are electrically connected through the connection structure in the insulating sublayer via, wherein the reference plane is a plane perpendicular to the thickness direction of the coil structure.

[0026] Exemplarily, the reference plane is also parallel to the plane where the magnetic conductive layer is located.

[0027] When M is 3, through the set crossing rule, the multiple wires in each internal coil group are changed from sequential arrangement to reverse arrangement along the radial direction, so that the wires on both sides pass through the middle position and are finally interchanged, thereby improving the uniformity of current distribution.

[0028] According to the first aspect, or any implementation of the first aspect above, M is 4; the four strands of wire are respectively a first wire, a second wire, a third wire and a fourth wire; the coil structure includes a first preset intersection area and a second preset intersection area; before the four strands of wire are wound to the first preset intersection area, the first wire, the second wire, the third wire and the fourth wire are arranged in sequence in the radial direction and away from the center of the coil structure; when the four strands of wire are wound to the first preset intersection area, the first wire of the first wiring sublayer and the second wire of the second wiring sublayer cross in the first preset intersection area, and the first wire of the second wiring sublayer is disconnected at the first preset intersection area, and the first wiring sublayer The second wire is disconnected at the first preset intersection area; the third wire of the first wiring sublayer crosses the fourth wire of the second wiring sublayer in the first preset intersection area, and the third wire of the second wiring sublayer is disconnected at the first preset intersection area, and the fourth wire of the first wiring sublayer is disconnected at the first preset intersection area; when the four strands of wire are wound to the second preset intersection area, the third wire and the fourth wire of the first wiring sublayer and the first wire and the second wire of the second wiring sublayer cross in the second preset intersection area, and the third wire and the fourth wire of the second wiring sublayer are disconnected at the second preset intersection area, and the first wire and the second wire of the first wiring sublayer are disconnected at the second preset intersection area.

[0029] When M is 4, through the set crossing rule, the multiple wires in each internal coil group are changed from sequential arrangement to reverse arrangement along the radial direction, so that the wires on both sides pass through the middle position and are finally interchanged, thereby improving the uniformity of current distribution.

[0030] According to the first aspect, or any implementation of the first aspect above, M is 5; the 5 strands of wire are divided into a first wire, a second wire, a third wire, a fourth wire, and a fifth wire; the coil structure includes a first preset intersection area and a second preset intersection area; at the first preset intersection area, the order of the first wire and the second wire is interchanged, the order of the fourth wire and the fifth wire is interchanged, and the order of the remaining third wires remains unchanged; at the second preset intersection area, the order of the intersection group consisting of the first wire and the second wire and the intersection group consisting of the fourth wire and the fifth wire is interchanged, and the order of the remaining third wires remains unchanged.

[0031] When M is 5, through the set crossing rule, the multiple wires in each internal coil group are changed from sequential arrangement to reverse arrangement along the radial direction, so that the wires on both sides pass through the middle position and are finally interchanged, thereby improving the uniformity of current distribution.

[0032] According to the first aspect, or any implementation of the first aspect above, the coil module further comprises: a magnetically conductive layer; a double-sided adhesive layer disposed between the magnetically conductive layer and the coil structure; along the thickness direction of the coil structure, the magnetically conductive layer comprises two insulating sublayers and a magnetically conductive sublayer disposed between the two insulating sublayers; the insulating sublayer in the magnetically conductive layer that contacts the coil structure has a hollow portion, the hollow portion exposing the magnetically conductive sublayer; the double-sided adhesive layer is disposed in the hollow portion and contacts the magnetically conductive sublayer, thereby further reducing the thickness of the coil module.

[0033] According to the first aspect, or any implementation of the first aspect above, the coil structure is an FPC coil. The FPC coil has good flatness, so a thin double-sided adhesive layer can be used to securely bond the magnetic conductive layer to the coil structure, facilitating a lightweight and thin design for devices employing the coil module.

[0034] In a second aspect, an embodiment of the present application provides a wireless charging receiving device, which includes: the coil module of the first aspect and any one of the first aspects.

[0035] The second aspect corresponds to the first aspect and any implementation of the first aspect. The technical effects corresponding to the second aspect can be referred to the technical effects corresponding to the first aspect and any implementation of the first aspect, and will not be repeated here.

[0036] In a third aspect, an embodiment of the present application provides a wireless charging system, which includes: a wireless charging transmitting device and a wireless charging receiving device according to the second aspect, wherein the wireless charging transmitting device is used to wirelessly charge the wireless charging receiving device.

[0037] 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 be referred 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

[0038] FIG1 is a schematic structural diagram of a wireless charging system provided in an embodiment of the present application;

[0039] FIG2 is a schematic diagram of a circuit structure of a wireless charging system provided in an embodiment of the present application;

[0040] FIG3 is a schematic structural diagram of the wireless charging receiving device shown in FIG1 ;

[0041] FIG4 is a diagram showing a film structure of a coil module provided in an embodiment of the present application;

[0042] FIG5 is a diagram showing a film layer structure of another coil module provided in an embodiment of the present application;

[0043] FIG6 a is a front structural schematic diagram of a coil structure provided in an embodiment of the present application;

[0044] FIG6 b is a front view of another coil structure provided in an embodiment of the present application;

[0045] FIG7 is a cross-sectional view of the coil shown in FIG6a along the AA' direction;

[0046] FIG8 a is a schematic diagram of the front structure of the first coil in the coil structure shown in FIG6 a ;

[0047] FIG8b is a schematic diagram of the front structure of the second coil in the coil structure shown in FIG6a;

[0048] FIG9 is a partial enlarged view of the BB area in FIG8b;

[0049] FIG10 is a front view of another coil structure provided in an embodiment of the present application;

[0050] FIG11 is a cross-sectional view of the coil shown in FIG10 along the DD' direction;

[0051] FIG12a is a schematic diagram of the front structure of the first wiring sub-layer in the coil structure shown in FIG10;

[0052] FIG12 b is a schematic diagram of the front structure of the second wiring sub-layer in the coil structure shown in FIG10 ;

[0053] FIG13 is a partial enlarged view of the EE area in FIG12 b;

[0054] FIG14 is a front view of another coil structure provided in an embodiment of the present application;

[0055] FIG15 is a cross-sectional view of the coil shown in FIG14 along the GG' direction;

[0056] FIG16a is a schematic diagram of the front structure of the first wiring sub-layer in the coil structure shown in FIG14;

[0057] FIG16 b is a schematic diagram of the front structure of the second wiring sublayer in the coil structure shown in FIG14 ;

[0058] FIG17 is a front view of another coil structure provided in an embodiment of the present application;

[0059] FIG18 is a cross-sectional view of the coil shown in FIG17 along the II' direction;

[0060] FIG19a is a schematic diagram of the front structure of the first wiring sub-layer in the coil structure shown in FIG17;

[0061] FIG19b is a schematic diagram of the front structure of the second wiring sublayer in the coil structure shown in FIG17;

[0062] FIG20 is a comparison diagram of the mutual inductance between the receiving coil and the transmitting coil when the number of turns of the coil structure is different in the embodiment of the present application;

[0063] FIG21 is a schematic diagram of a cross structure of different strands of wire in the same coil assembly provided by an embodiment of the present application;

[0064] FIG22 is a schematic diagram of the cross structure shown in FIG21;

[0065] FIG23 is a cross-sectional view of FIG22 along the OO' direction;

[0066] FIG24 is a schematic diagram of another cross structure of different strands of wire in the same coil assembly provided in an embodiment of the present application;

[0067] FIG25 is an enlarged view of the KK region in FIG8 a;

[0068] FIG26 is an enlarged view of the MM area in FIG8 b;

[0069] FIG27 is an enlarged view of the LL region in FIG8 a;

[0070] Figure 28 is an enlarged view of the NN region in Figure 8b;

[0071] FIG29 is a schematic diagram of another cross structure of different strands of conductive wires in the same coil assembly provided in an embodiment of the present application. DETAILED DESCRIPTION

[0072] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0073] The term "and / or" in this article is merely a description of the association relationship between 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.

[0074] In the description and claims of the embodiments of this application, the terms "first" and "second" are used to distinguish different objects, rather than to describe a specific order of objects. For example, the terms "first target object" and "second target object" are used to distinguish different objects, rather than to describe a specific order of objects.

[0075] In the embodiments of this 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 this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0076] In the description of the embodiments of this application, unless otherwise specified, "multiple" means two or more. For example, "multiple processing units" means two or more processing units; "multiple systems" means two or more systems.

[0077] First, the terms involved in this application are explained:

[0078] Layers refer to the number of planes in which the wires contained in the coils provided by this 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 considered a single-layer coil. When all the wires contained in a coil are not arranged on the same plane, for example, the first wire is wound on a first planar layer and the second wire is wound on a second planar layer, and the first and second wires are electrically connected through vias in the insulating layer between the first and second planar layers, the coil is considered a two-layer coil.

[0079] Turns refers to the number of turns of wire in each coil. It's worth noting that even if any one turn of wire is distributed across two planar layers and electrically connected vias in the insulating layer between the two planar layers, it still counts as one turn.

[0080] The number of strands refers to the number of parallel wires when the coil is wound.

[0081] Next, the technical scenarios involved in the embodiments of the present application are described.

[0082] 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, headphones, 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 computer, a laptop computer, a mobile phone, etc., and the device to be charged can be a stylus, a magnetic keyboard, etc.

[0083] The wireless charging device 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.

[0084] To help those skilled in the art better understand the technical solutions provided by the embodiments of this application, the following briefly introduces the principles of wireless charging in a wireless charging technology scenario. This description is based on an example in which the wireless charging transmitter is a wireless charger and the wireless charging receiver is a mobile phone. The rest of the following description is also based on an example in which the wireless charging transmitter is a wireless charger and the wireless charging receiver is a mobile phone.

[0085] Refer to Figure 1, which is a schematic diagram of the structure of a wireless charging system provided in an embodiment of the present application. As shown in Figure 1, wireless charging system 01 includes a wireless charging transmitter 10 and a wireless charging receiver 20. Wireless charging transmitter 10 can be a wireless charger, and wireless charging receiver 20 can be a mobile phone. The wireless charger performs wireless charging for the mobile phone.

[0086] It should be noted that the wireless charger shown in Figure 1 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 flat and supports the mobile phone to be placed horizontally on it.

[0087] 2 , which is a schematic diagram of a circuit structure of a wireless charging system according to an embodiment of the present application. As shown in FIG2 , a wireless charging transmitting device 10 includes a power supply 11 and a wireless transmitting device 12 .

[0088] The power supply 11 is used to provide a DC voltage. In order to distinguish it from other DC voltages, the DC voltage provided by the power supply 11 is a first DC voltage.

[0089] The wireless transmitting device 12 includes a direct current (DC) / alternating current (AC) circuit 122 , a resonant capacitor C1 , and a transmitting coil L1 .

[0090] 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 configured to convert a first DC voltage output by the power supply 11 into a stable second DC voltage. Exemplarily, the voltage conversion circuit 121 may be a boost circuit (e.g., a boost circuit, a boost transformer, or a power amplifier) ​​configured to boost the first DC voltage output by the power supply 11 before outputting it.

[0091] When the voltage conversion circuit 121 is a boost circuit, it can increase the potential difference between the wireless charging transmitting device 10 and the wireless charging receiving device 20, thereby improving the energy transfer capability of the system and facilitating high-power transmission.

[0092] Of course, the voltage conversion circuit 121 is not limited to a boost circuit, and 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.

[0093] The direct current (DC) / alternating current (AC) circuit 122 is electrically connected to the voltage conversion circuit 121 and is configured to convert the second DC voltage output by the voltage conversion circuit 121 into alternating current. For example, the DC / AC circuit 122 may be an inverter bridge (including an upper transistor, a lower transistor, and a digital module), and its circuit structure may be a full-bridge circuit or a half-bridge circuit. The DC / AC circuit 122 is also referred to as a transmit (TX) chip.

[0094] Resonant capacitor C1 and transmitting coil L1 are connected in series to form a series resonant network. Transmitting coil L1 is electrically connected to DC / AC circuit 122 via resonant capacitor C1. As DC / AC circuit 122 charges and discharges resonant capacitor C1 and transmitting coil L1, transmitting coil L1 can convert alternating current into an alternating magnetic field.

[0095] In addition, the wireless charging transmitter 10 also includes structures such as a printed circuit board (PCB) and a fan (both shown in the figure). The DC / AC circuit 122 and resonant capacitor C1 in the wireless transmitter 12 are arranged on the PCB to achieve electrical connection between the various structures (enabling signal transmission and interaction). The transmitting coil L1 can be electrically connected to the PCB via a coil connector (not shown in the figure), thereby achieving electrical connection with the DC / AC circuit 122 and resonant capacitor C1. The provision of the fan can reduce the heat generated by the wireless charging transmitter 10 when charging the wireless charging receiver 20.

[0096] FIG3 is a schematic diagram of the structure of the wireless charging receiving device shown in FIG1 . As shown in FIG3 , the wireless charging receiving device 20, such as a mobile phone, includes a housing 201, a display screen 202, and a middle frame 203. The display screen 202 and the housing 201 are located on either side of the middle frame 203, respectively. The housing 201, the display screen 202, and the middle frame 203 can enclose a housing. The housing cavity is provided with a PCB 204, a PCB bracket (not shown), a battery (including a battery cell, a long side protection plate, a short side protection plate, etc.) 205, a flash 206, a rear camera 207, and a near field communication (NFC) module (not shown). The PCB 204 is provided with some components, and the PCB bracket can fix some components on the PCB 204 and / or be used to support some components. In this embodiment of the present application, the PCB 204 includes a main board 2041 and a sub-board 2042. The rear camera 207 can be electrically connected to the main board 2041 via an FPC 208. There may be one or more rear cameras 207. When there are multiple rear cameras 207, the functions of the multiple rear cameras 207 may be different. For example, in one possible implementation, one rear camera 207 is responsible for main photography, one rear camera 207 is responsible for zoom, and one rear camera 207 is responsible for wide-angle photography.

[0097] The mobile phone also includes a camera decoration 209 for decorating the camera. A decoration hole 2011 is opened on the housing 201. The camera decoration 209 is set at the decoration hole 2011, and the rear camera 207 is opposite to the camera decoration 209.

[0098] Continuing with FIG2 , the wireless charging receiving device 20 further includes a wireless receiving device 22 and a load 21. The load 21 is a load resistor equivalent to the power consumption unit at the back end of the system. The load 21 can be a battery or other device that needs to be charged.

[0099] The wireless receiving device 22 includes a receiving coil L2 , a resonant capacitor C2 , and an AC / DC circuit 222 .

[0100] The receiving coil L2 is located in the accommodating cavity, and illustratively, can be located between the battery 205 and the housing 201. The receiving coil L2 is electrically connected to the PCB 204 via a coil connector (not shown in the figure).

[0101] The resonant capacitor C2 and the AC / DC circuit 222 are disposed on the PCB 204 (e.g., the mainboard 2041). The receiving coil L2 is electrically connected to the resonant capacitor C2 and the AC / DC circuit 222 via the PCB 204 (enabling signal transmission and interaction). In addition, the AC / DC circuit 222 is also electrically connected to the battery 21.

[0102] When the wireless charging transmitting device 10 needs to charge the wireless charging receiving device 20, the receiving coil L2 is close to or in contact with the transmitting coil L1. At this time, the receiving coil L2 in the wireless charging receiving device 20 generates alternating current through electromagnetic induction. 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 (including an upper tube, a lower tube, a digital module, a sensor, etc.), 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 (RX) chip.

[0103] In some embodiments, when the DC power output by the AC / DC circuit 222 is too large to be directly supplied 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 configured 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 known as a buck circuit).

[0104] In some embodiments, the voltage conversion circuit 221 can also be a switched capacitor (SC) circuit (not shown in the figure). The SC circuit can achieve, for example, a 2:1, 4:1 ratio 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.

[0105] 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. The charging signal received by the USB interface is transmitted to the voltage conversion circuit 221, so that the voltage conversion circuit 221 reduces the larger charging signal to the charging signal required by the load 21 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 MOSFET. When the OVP circuit detects that the voltage connected to the USB interface is too high (exceeds the threshold voltage), it can actively cut off the connection between the voltage conversion circuit 221 and the USB interface to protect the voltage conversion circuit 221.

[0106] The above describes the structure of wireless charging system 01. As can be seen, wireless charging system 01 transmits wireless power based on magnetic coupling between transmitting coil L1 and receiving coil L2. When the electromagnetic coupling coefficient between transmitting coil L1 and receiving coil L2 is high, the power transmission efficiency between the two coils is higher, and charging efficiency is faster. The electromagnetic coupling coefficient between transmitting coil L1 and receiving coil L2 is generally related to factors such as coil size, coil spacing, and alignment. For example, if the coil spacing between the transmitting and receiving coils and the alignment between transmitting coil L1 and receiving coil L2 are consistent, a thicker receiving coil reduces the impedance of the receiving coil, increases the electromagnetic coupling coefficient between the transmitting and receiving coils, and improves the power transmission efficiency between the transmitting and receiving coils, resulting in faster charging efficiency. However, a thicker coil is not conducive to the slimming down of electronic devices and affects the user's grip. In other words, existing wireless charging solutions cannot simultaneously achieve high charging efficiency and a slimmer electronic device equipped with a receiving coil.

[0107] 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 device, and the coil module operates in a magnetic coupling or magnetic resonance wireless power transmission system with a frequency less than or equal to 500Khz. The thickness of the coil module provided by the present application is very thin, for example, the thickness of the coil module is less than or equal to 0.2mm. And at a thickness less than or equal to 0.2mm, by reasonably setting the coil module, such as selecting a suitable number of coil turns, number of coil strands, etc., the effect of high-power charging can be achieved. In other words, the coil module provided by the present application achieves coil thinning by optimizing the design of the coil, and takes into account the effects of high-power and high-freedom wireless charging.

[0108] It should be noted that the coil module provided in this application is not only applicable to wireless charging scenarios, but also to other scenarios that utilize the principle of electromagnetic induction.

[0109] The structure of the coil module provided in the embodiment of the present application is described below.

[0110] Refer to Figure 4, which is a film layer structure diagram of a coil module provided in an embodiment of the present application. As shown in Figure 4, the coil module 30 includes a coil structure 31 and a magnetic conductive layer 32 located on one side of the coil structure 31. 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. 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 is provided in a wireless charging receiving device, which may include structures such as a PCB board, a PCB bracket, a battery, and a middle frame. However, structures such as a PCB board, a PCB bracket, a battery, and a middle frame are generally made of metal, and the magnetic field will generate eddy current losses on the PCB board, PCB bracket, battery, and middle frame. 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 the PCB board, PCB bracket, battery, and middle frame.

[0111] Exemplarily, the magnetic conductive layer 32 includes two insulating sublayers 321 and a magnetic conductive sublayer 322 located between the two insulating sublayers 321. The magnetic conductive sublayer 322 includes a soft magnetic material, such as ferrite or nanocrystals. FIG4 illustrates the soft magnetic material including 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 3222 for bonding two adjacent layers of nanocrystals 3221 together. FIG4 illustrates the magnetic conductive sublayer 322 including four layers of nanocrystals 3221 and five layers of adhesive 3222 as an example. Accordingly, the insulating sublayer 321 can be a nanocrystal black film.

[0112] The thickness H21 of the nanocrystalline black film can be 5 μm, the thickness H22 of the nanocrystals 3221 can be 17 μm, and the thickness H23 of the adhesive 3222 can be 3 μm. Therefore, the overall thickness H2 of the magnetic conductive layer 32 can be 93 μm. Of course, the thickness of the nanocrystalline black film, the thickness of the nanocrystals 3221, and / or the thickness of the adhesive 3222 can be adaptively varied to meet different requirements.

[0113] The coil structure 31 may be an FPC coil; of course, the coil structure 31 is not limited to an FPC coil. The coil structure 31 may also be a multi-stranded enameled wire coil, etc., wherein FIG4 is used as an example for the coil structure 31 being an FPC coil. Continuing with FIG4 , the coil structure 31 includes two layers of protective film 311 and a functional layer 312 located between the two layers of protective film 311. The protective film 311 includes a polyimide (PI) layer 3111 and an adhesive 3112 that sets the PI layer 3111 on the functional layer 312. The functional layer 312 includes at least two wiring sublayers 3121 and an insulating sublayer 3122 located between two adjacent wiring sublayers 3121. FIG4 is used as an example for the functional layer 312 including two layers of wiring sublayers 3121.

[0114] 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.

[0115] In order to achieve electrical connection between the two wiring sub-layers 3121, a via is provided on the insulating sub-layer 3122 located between the two wiring sub-layers 3121, and a connection structure (not shown in the figure) connecting the two wiring sub-layers 3121 is provided in the via. The embodiment of the present application does not limit the manner in which the connection structure is formed. For example, referring to FIG4 , a whole connection layer 3123 can be plated on the wiring sub-layer 3121. During the coating process, part of the material of the connection layer 3123 will be deposited into the via to form a connection structure. For another example, a connection structure (not shown in the figure) can be formed directly in the via of the insulating sub-layer 3122.

[0116] The thickness H1 of the coil structure 31 may be greater than or equal to 0.07 mm and less than or equal to 0.175 mm.

[0117] Exemplarily, the thickness H1 of the coil structure 31 can be 103.5 μm, wherein the thickness H11 of the PI layer 3111 can be 7.5 μm, the thickness H12 of the adhesive 3112 can be 5 μm, the thickness H13 of the insulating sublayer 3122 can be 12.5 μm, the thickness H14 of the wiring sublayer 3121 can be 15 μm, and the thickness H15 of the connecting layer 3123 can be 18 μm.

[0118] In addition, the double-sided tape 33 between the coil structure 31 and the magnetic conductive layer 32 can be 10 μm thick. In this case, when the thickness H1 of the coil structure 31 is 103.5 μm and the thickness H2 of the magnetic conductive layer 32 is 93 μm, the thickness of the coil module 30 is 206.5 μm, that is, the thickness of the coil module 30 is relatively thin.

[0119] In order to further reduce the thickness of the coil module 30, refer to Figure 5, which is a membrane layer structure diagram of another coil module provided in an embodiment of the present application. As shown in Figure 5, the insulating sublayer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 is provided with a hollow portion 3211, and the hollow portion 3211 can expose the adhesive 3222 between the insulating 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 contacts the adhesive 3222 between the insulating sublayer 321 and the nanocrystal 3221. In other words, the area where the insulating sublayer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 and the coil structure 31 overlaps is partially removed, so that the double-sided tape 33 that bonds the coil structure 31 and the magnetic conductive layer 32 is directly bonded to the adhesive 3222 on the nanocrystal 3221.

[0120] It is understood that 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 must still be maintained at 10 μm. Therefore, the thickness of the insulating 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 are also 10 μm. This reduces the thickness of the coil module 30 by 5 μm (the thickness of one insulating sublayer 321), resulting in a thickness of 201.5 μm, which is relatively thin.

[0121] As can be seen from the above, the thickness H1 of the coil structure 31 is greater than or equal to 0.07 mm and less than or equal to 0.175 mm. When the thickness of the coil structure 31 is smaller, such as less than 103.5 μm, the thickness of the coil module 30 can be further reduced, such as less than 0.2 mm.

[0122] The above describes the membrane structure of the coil module. From the above content, it can be seen that the thickness of the coil module of the present application can be less than or equal to 0.2 mm. 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, refer to Figures 6a and 6b. Figure 6a is a front structural schematic diagram of a coil structure provided in an embodiment of the present application, and Figure 6b is a front structural schematic diagram of another coil structure provided in an embodiment of the present application. As shown in Figures 6a and 6b, the coil structure 31 of the embodiment of the present application can be a ring coil, wherein the outer diameter d1 of the coil is less than or equal to 52 mm and greater than or equal to 46 mm; the inner diameter d2 of the coil is less than or equal to 28 mm and less than or equal to 16 mm. Exemplarily, the coil outer diameter d1 is 46 mm, 47 mm, 48 mm, 49 mm, 50 mm, 51 mm or 52 mm; the coil inner diameter d2 is 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm or 28 mm.

[0123] It should be noted that the embodiments of the present application do not limit the specific shape of the toroidal coil, and those skilled in the art can configure it according to actual conditions. For example, the toroidal coil includes a circular toroidal coil, a rectangular toroidal coil, a hexagonal toroidal coil, an octagonal toroidal coil, etc. The embodiments of the present application are described using a circular toroidal coil as an example.

[0124] In addition, the inductance L of the coil structure 31 provided in the embodiment of the present application is less than or equal to 6 μH and greater than or equal to 4 μH. When the coil module operates in magnetic coupling or magnetic resonance wireless power transmission systems at different frequencies, the inductance of the coil structure 31 varies. For example, when the coil module operates in a magnetic coupling or magnetic resonance wireless power transmission system at a frequency of 100 kHz, the inductance L of the coil structure 31 is less than or equal to 5.2 μH and greater than or equal to 4.2 μH.

[0125] Continuing with Figures 6a and 6b, the coil structure 31 includes a first end D1, a second end D2, and N coil groups 31a connected in series. The first end D1 and the second end D2 are connected by the N coil groups 31a connected in series. Each coil group 31a constitutes one turn (i.e., one revolution) of the coil structure 31. N is less than or equal to 8.5 and greater than or equal to 7.5, meaning the number of turns of the coil structure 31 is between 7.5 and 8.5. For example, the number of turns of the coil structure 31 can be 7.5 turns (as shown in Figure 6b), 8 turns (as shown in Figure 6a), or 8.5 turns (not shown). A 0.5 turn represents half a winding of the wire. For example, 7.5 turns can be formed by winding half a turn around the outermost coil group 31a among the seven coil groups 31a, or by winding half a turn around the innermost coil group 31a among the seven coil groups 31a. FIG. 6 b illustrates 7.5 turns by winding half a turn around the innermost coil group 31a among the seven coil groups 31a as an example. 8.5 turns can be formed by winding half a turn around the outermost coil group 31a among the eight coil groups 31a, or by winding half a turn around the innermost coil group 31a among the eight coil groups 31a.

[0126] Each coil assembly 31a includes M strands of wire 311a, where M can be less than or equal to 5 and greater than or equal to 3. For example, M is 3, 4, or 5. Figures 6a and 6b illustrate M as 4. That is, the coil structure 31 is continuously wound from the first end D1 (forming N coil assemblies 31a connected in series) to the second end D2, distributed across two wiring sublayers 3121. Current is input from the first end D1, passes through the N coil assemblies 31a, and is output from the second end D2.

[0127] M can be set to be less than or equal to 5 and greater than or equal to 3 because the outer diameter d1 of the annular coil is less than or equal to 52 mm and greater than or equal to 46 mm, and the inner diameter d2 of the coil is less than or equal to 28 mm and less than or equal to 16 mm. This means that the area for the conductors 311a is limited. Within this limited area, the impedance of the wiring sublayer 3121 is not increased due to the large number of conductors 311a, resulting in a larger gap between adjacent conductors 311a. Furthermore, the skin effect, which reduces the number of conductors 311a and reduces the number of current paths, does not affect current transmission.

[0128] Continuing with FIG6 a , the N coil assemblies 31 a include L internal coil assemblies 31 a (the coil assemblies 31 a within the ZZ region in FIG6 a are the internal coil assemblies 31 a, where the ZZ region is the region enclosed by the innermost curved ring and the middle curved ring), where L is less than or equal to N. When L is less than N, the N coil assemblies 31 a also include (NL) external coil assemblies 31 a disposed around the L internal coil assemblies 31 a (the coil assemblies 31 a within the YY region in FIG6 a are the external coil assemblies 31 a, where the YY region is the region enclosed by the outermost curved ring and the middle curved ring).

[0129] Referring to Figures 7, 8a, and 8b, Figure 7 is a cross-sectional view of the coil shown in Figure 6a along the AA' direction, Figure 8a is a schematic front view of the first wiring sublayer in the coil structure shown in Figure 6a, and Figure 8b is a schematic front view of the second wiring sublayer in the coil structure shown in Figure 6a. As shown in Figures 6a, 7, 8a, and 8b, when L equals N, that is, when the N coil assemblies 31a do not include the external coil assemblies 31a, the L internal coil assemblies 31a are wound sequentially along the longitudinal direction, and the L internal coil assemblies 31a are wired on both sides, that is, the L internal coil assemblies 31a are arranged in two wiring sublayers 3121. For the purpose of distinction, the two wiring sublayers 3121 are respectively the first wiring sublayer 3121a and the second wiring sublayer 3121b, that is, the L internal coil assemblies 31a are distributed in parallel on the two wiring sublayers 3121. That is, L groups of internal coils 31a are wound around each of the first wiring sublayer 3121a and the second wiring sublayer 3121b, and the L groups of internal coils 31a of the first wiring sublayer 3121a and the L groups of internal coils 31a of the second wiring sublayer 3121b are electrically connected respectively.

[0130] When L is less than N, L groups of internal coil assemblies 31a are wound sequentially along the longitudinal direction. L groups of internal coil assemblies 31a are wound on both the first wiring sub-layer 3121a and the second wiring sub-layer 3121b, and the L groups of internal coil assemblies 31a on the first wiring sub-layer 3121a and the L groups of internal coil assemblies 31a on the second wiring sub-layer 3121b are electrically connected to each other. Of the (NL) groups of external coil assemblies 31a, (NL) / 2 groups of external coil assemblies 31a are arranged on the first wiring sub-layer 3121a and connected in series with the L groups of internal coil assemblies 31a on the first wiring sub-layer 3121a. The remaining (NL) / 2 groups of external coil assemblies 31a are arranged on the second wiring sub-layer 3121b and connected in series with the L groups of internal coil assemblies 31a on the second wiring sub-layer 3121b, resulting in a total of N groups of coil assemblies 31a connected in series.

[0131] To facilitate understanding of the above content, the following describes the circuit design of the coil structure provided in the embodiments of the present application with reference to specific examples. The description is given using an example where N is 8, i.e., the coil structure 31 includes 8 coil groups 31a connected in series (the number of turns of the coil structure 31 is 8).

[0132] In Example 1, L is equal to 4, and M is equal to 4 or 5. This example uses M as 4 for illustration. Continuing with Figures 7, 8a, and 8b, the eight coil assemblies 31a include a first coil assembly 31a1, a second coil assembly 31a2, a third coil assembly 31a3, a fourth coil assembly 31a4, a fifth coil assembly 31a5, a sixth coil assembly 31a6, a seventh coil assembly 31a7, and an eighth coil assembly 31a8. The eight coil assemblies 31a include four inner coil assemblies 31a and four outer coil assemblies 31a surrounding the four inner coil assemblies 31a. The four inner coil assemblies 31a are the third coil assembly 31a3, the fourth coil assembly 31a4, the fifth coil assembly 31a5, and the sixth coil assembly 31a6. The four outer coil assemblies 31a are the first coil assembly 31a1, the second coil assembly 31a2, the seventh coil assembly 31a7, and the eighth coil assembly 31a8.

[0133] The first coil group 31a1, the second coil group 31a2, the third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, and the sixth coil group 31a6 are radially wound sequentially on the first wiring sub-layer 3121a. The first coil group 31a1 is connected to the first end D1. The third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, and the sixth coil group 31a6 are also radially wound sequentially on the second wiring sub-layer 3121b. The four wires 311a of the third coil group 31a3 located in the first wiring sublayer 3121a are electrically connected to the four wires 311a of the third coil group 31a3 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The four wires 311a of the fourth coil group 31a4 located in the first wiring sublayer 3121a are electrically connected to the four wires 311a of the fourth coil group 31a4 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The four strands of wire 311a of the fifth coil group 31a5 located in the first wiring sublayer 3121a are electrically connected to the four strands of wire 311a of the fifth coil group 31a5 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122, and the four strands of wire 311a of the sixth coil group 31a6 located in the first wiring sublayer 3121a are electrically connected to the four strands of wire 311a of the sixth coil group 31a6 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122.

[0134] The seventh coil group 31a7, located on the second wiring sub-layer 3121b, wraps around the outside of the third coil group 31a3. The eighth coil group 31a8, located on the second wiring sub-layer 3121b, wraps around the outside of the seventh coil group 31a7. The eighth coil group 31a8 is connected to the second end D2. The four wire strands 311a of the eighth coil group 31a8 are respectively connected to the four wire strands 311a of the seventh coil group 31a7, connecting the seventh coil group 31a7 and the eighth coil group 31a8 in series.

[0135] In addition, in conjunction with Figure 9, which is a partial enlarged view of the BB area in Figure 8b, there is a disconnect between the third coil group 31a3 and the fourth coil group 31a4 in the second wiring sublayer 3121b, a disconnect between the third coil group 31a3 and the fourth coil group 31a4 in the second wiring sublayer 3121b, a disconnect between the fourth coil group 31a4 and the fifth coil group 31a5 in the second wiring sublayer 3121b, and a disconnect between the fifth coil group 31a5 and the sixth coil group 31a6 in the second wiring sublayer 3121b. The four wires 311a of the sixth coil group 31a6 pass through the disconnected area (such as the CC area in Figure 9) and are respectively connected to the four wires 311a of the seventh coil group 31a7.

[0136] It is understood that when the coil structure 31 has 7.5 turns, the half turn after the fifth coil group 31a5 needs to pass through the center of the coil structure 31 to reach the disconnected region, and then pass through the disconnected region to connect to the sixth coil group 31a6 located on the second wiring sub-layer 3121b. The sixth coil group 31a6 is connected in series with the seventh coil group 31a7, and the seventh coil group 31a7 is connected to the second end D2. Similarly, when the coil structure 31 has 8.5 turns, the half turn after the sixth coil group 31a6 needs to pass through the center of the coil structure 31 to reach the disconnected region, and then pass through the disconnected region to connect to the seventh coil group 31a7 located on the second wiring sub-layer 3121b. The seventh coil group 31a7 is connected in series with the eighth coil group 31a8, and the eighth coil group 31a8 is connected to the second end D2.

[0137] That is to say, in this example, among the 8 groups of coil groups 31a (the number of turns of the coil structure 31 is 8 turns), 4 groups of internal coil groups 31a (i.e., 4 turns) are double-sided, and the remaining 4 groups of external coil groups 31a (i.e., 4 turns) are evenly distributed on the first wiring sublayer 3121a and the second wiring sublayer 3121b, that is, the first wiring sublayer 3121a and the second wiring sublayer 3121b each have 2 groups of external coil groups 31a (i.e., 2 turns).

[0138] In Example 2, L is equal to 2, and M is equal to 4 or 5. This example is illustrated using M as 4. Referring to Figures 10, 11, 12a, and 12b, Figure 10 is a schematic front view of another coil structure provided in an embodiment of the present application, Figure 11 is a cross-sectional view of the coil shown in Figure 10 along the DD' direction, Figure 12a is a schematic front view of the first wiring sublayer in the coil structure shown in Figure 10, and Figure 12b is a schematic front view of the second wiring sublayer in the coil structure shown in Figure 10. As shown in Figures 10, 11, 12a, and 12b, the eight coil assemblies 31a include a first coil assembly 31a1, a second coil assembly 31a2, a third coil assembly 31a3, a fourth coil assembly 31a4, a fifth coil assembly 31a5, a sixth coil assembly 31a6, a seventh coil assembly 31a7, and an eighth coil assembly 31a8. The eight coil assemblies 31a include two inner coil assemblies 31a and six outer coil assemblies 31a surrounding the two inner coil assemblies 31a. The two inner coil assemblies 31a are the fourth coil assembly 31a4 and the fifth coil assembly 31a5. The six outer coil assemblies 31a are the first coil assembly 31a1, the second coil assembly 31a2, the third coil assembly 31a3, the sixth coil assembly 31a6, the seventh coil assembly 31a7, and the eighth coil assembly 31a8.

[0139] The first coil group 31a1, the second coil group 31a2, the third coil group 31a3, the fourth coil group 31a4, and the fifth coil group 31a5 are radially wound sequentially around the first wiring sub-layer 3121a. The first coil group 31a1 is connected to the first end D1. The fourth coil group 31a4 and the fifth coil group 31a5 are also radially wound sequentially around the second wiring sub-layer 3121b. The four wire strands 311a of the fourth coil group 31a4 in the first wiring sub-layer 3121a are electrically connected to the four wire strands 311a of the fourth coil group 31a4 in the second wiring sub-layer 3121b via connection structures within the via holes in the insulating sub-layer 3122. The four wire strands 311a of the fifth coil group 31a5 in the first wiring sub-layer 3121a are electrically connected to the four wire strands 311a of the fifth coil group 31a5 in the second wiring sub-layer 3121b via connection structures within the via holes in the insulating sub-layer 3122.

[0140] The sixth coil group 31a6 located in the second wiring sub-layer 3121b surrounds the outside of the fourth coil group 31a4. The seventh coil group 31a7 located in the second wiring sub-layer 3121b surrounds the outside of the sixth coil group 31a6. The eighth coil group 31a8 located in the second wiring sub-layer 3121b surrounds the outside of the seventh coil group 31a7. The eighth coil group 31a8 is connected to the second end D2. The four wires 311a of the eighth coil group 31a8 are respectively connected to the four wires 311a of the seventh coil group 31a7, connecting the seventh coil group 31a7 and the eighth coil group 31a8 in series. The four wires 311a of the seventh coil group 31a7 are respectively connected to the four wires 311a of the sixth coil group 31a6, connecting the sixth coil group 31a6 and the seventh coil group 31a7 in series.

[0141] In addition, Figure 13 is a partial enlarged view of the EE area in Figure 12b. The fourth coil group 31a4 and the fifth coil group 31a5 located on the second wiring sublayer 3121b are disconnected, and the four wires 311a of the fifth coil group 31a5 pass through the disconnected area (such as the FF area in Figure 13) and are respectively connected to the four wires 311a of the sixth coil group 31a6.

[0142] That is to say, in this example, among the 8 groups of coil groups 31a (the number of turns of the coil structure 31 is 8 turns), 2 groups of internal coil groups 31a (i.e., 2 turns) are double-sided, and the remaining 6 groups of external coil groups 31a (i.e., 6 turns) are evenly distributed on the first wiring sublayer 3121a and the second wiring sublayer 3121b, that is, the first wiring sublayer 3121a and the second wiring sublayer 3121b each have 3 groups of external coil groups 31a (i.e., 3 turns each).

[0143] Example 3: L is equal to 6, and M is equal to 3, 4, or 5. Referring to Figures 14, 15, 16a, and 16b, Figure 14 is a front structural schematic diagram of another coil structure provided in an embodiment of the present application, Figure 15 is a cross-sectional view of the coil shown in Figure 14 along the GG' direction, Figure 16a is a front structural schematic diagram of the first wiring sublayer in the coil structure shown in Figure 14, and Figure 16b is a front structural schematic diagram of the second wiring sublayer in the coil structure shown in Figure 14. Figures 14, 15, 16a, and 16b do not show the number of wire strands in each coil group. As shown in Figures 14, 15, 16a, and 16b, the eight coil assemblies 31a include a first coil assembly 31a1, a second coil assembly 31a2, a third coil assembly 31a3, a fourth coil assembly 31a4, a fifth coil assembly 31a5, a sixth coil assembly 31a6, a seventh coil assembly 31a7, and an eighth coil assembly 31a8. The eight coil assemblies 31a include six inner coil assemblies 31a and two outer coil assemblies 31a surrounding the six inner coil assemblies 31a. The six inner coil assemblies 31a are the second coil assembly 31a2, the third coil assembly 31a3, the fourth coil assembly 31a4, the fifth coil assembly 31a5, the sixth coil assembly 31a6, and the seventh coil assembly 31a7. The two outer coil assemblies 31a are the first coil assembly 31a1 and the eighth coil assembly 31a8.

[0144] The first coil group 31a1, the second coil group 31a2, the third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, the sixth coil group 31a6, and the seventh coil group 31a7 are radially wound sequentially on the first wiring sub-layer 3121a. The first coil group 31a1 is connected to the first end D1. The second coil group 31a2, the third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, the sixth coil group 31a6, and the seventh coil group 31a7 are also radially wound sequentially on the second wiring sub-layer 3121b. The M-stranded wires 311a of the second coil group 31a2 located in the first wiring sublayer 3121a are electrically connected to the M-stranded wires 311a of the second coil group 31a2 located in the second wiring sublayer 3121b through the connection structures in the via holes of the insulating sublayer 3122. The M-stranded wires 311a of the third coil group 31a3 located in the first wiring sublayer 3121a are electrically connected to the M-stranded wires 311a of the third coil group 31a3 located in the second wiring sublayer 3121b through the connection structures in the via holes of the insulating sublayer 3122. The M-stranded wires 311a of the fourth coil group 31a4 located in the first wiring sublayer 3121a are electrically connected to the M-stranded wires 311a of the fourth coil group 31a4 located in the second wiring sublayer 3121b through the connection structures in the via holes of the insulating sublayer 3122. The M-strand wires 311a of the fifth coil group 31a5 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the fifth coil group 31a5 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the sixth coil group 31a6 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the sixth coil group 31a6 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the seventh coil group 31a7 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the seventh coil group 31a7 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122.

[0145] The eighth coil group 31a8 located in the second wiring sub-layer 3121b surrounds the outside of the second coil group 31a2 and is connected to the second end D2.

[0146] In addition, referring to Figure 16b, the second coil group 31a2 and the third coil group 31a3 located in the second wiring sublayer 3121b are disconnected, the third coil group 31a3 and the fourth coil group 31a4 located in the second wiring sublayer 3121b are disconnected, the fourth coil group 31a4 and the fifth coil group 31a5 located in the second wiring sublayer 3121b are disconnected, the fifth coil group 31a5 and the sixth coil group 31a6 located in the second wiring sublayer 3121b are disconnected, and the sixth coil group 31a6 and the seventh coil group 31a7 located in the second wiring sublayer 3121b are disconnected. The M-strand wires 311a of the seventh coil group 31a7 pass through the disconnected area (such as the HH area in Figure 16b) and are respectively connected to the M-strand wires 311a of the eighth coil group 31a8.

[0147] That is to say, in this example, among the 8 groups of coil groups 31a (the number of turns of the coil structure 31 is 8 turns), 6 groups of internal coil groups 31a (i.e., 6 turns) are double-sided, and the remaining 2 groups of external coil groups 31a (i.e., 2 turns) are evenly distributed on the first wiring sublayer 3121a and the second wiring sublayer 3121b, that is, the first wiring sublayer 3121a and the second wiring sublayer 3121b each have 1 group of external coil groups 31a (i.e., 1 turn each).

[0148] Example 4: L is equal to 8, and M is equal to 3 or 4. Referring to Figures 17, 18, 19a, and 19b, Figure 17 is a front structural schematic diagram of another coil structure provided in an embodiment of the present application, Figure 18 is a cross-sectional view of the coil shown in Figure 17 along the II' direction, Figure 19a is a front structural schematic diagram of the first wiring sublayer in the coil structure shown in Figure 17, and Figure 19b is a front structural schematic diagram of the second wiring sublayer in the coil structure shown in Figure 17, wherein Figures 17, 18, 19a, and 19b do not show the number of wire strands in each coil group. As shown in Figures 17, 18, 19a, and 19b, the eight coil groups 31a include a first coil group 31a1, a second coil group 31a2, a third coil group 31a3, a fourth coil group 31a4, a fifth coil group 31a5, a sixth coil group 31a6, a seventh coil group 31a7, and an eighth coil group 31a8. The eight coil groups 31 are all internal coil groups 31a.

[0149] The first coil group 31a1, the second coil group 31a2, the third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, the sixth coil group 31a6, the seventh coil group 31a7, and the eighth coil group 31a8 are radially wound sequentially on the first wiring sub-layer 3121a. The first coil group 31a1 is connected to the first end D1. The first coil group 31a1, the second coil group 31a2, the third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, the sixth coil group 31a6, the seventh coil group 31a7, and the eighth coil group 31a8 are also radially wound sequentially on the second wiring sub-layer 3121b. The M-strand wires 311a of the first coil group 31a1 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the first coil group 31a1 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the second coil group 31a2 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the second coil group 31a2 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the third coil group 31a3 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the third coil group 31a3 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the fourth coil group 31a4 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the fourth coil group 31a4 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the fifth coil group 31a5 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the fifth coil group 31a5 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand wires 311a of the sixth coil group 31a6 located in the first wiring sublayer 3121a are electrically connected to the M-strand wires 311a of the sixth coil group 31a6 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122. The M-strand conductors 311a of the seventh coil group 31a7 located in the first wiring sublayer 3121a are electrically connected to the M-strand conductors 311a of the seventh coil group 31a7 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122, and the M-strand conductors 311a of the eighth coil group 31a8 located in the first wiring sublayer 3121a are electrically connected to the M-strand conductors 311a of the eighth coil group 31a8 located in the second wiring sublayer 3121b through the connection structure in the via hole of the insulating sublayer 3122.

[0150] 19 b , the first coil group 31a1 and the second coil group 31a2 in the second wiring sublayer 3121 b are disconnected, the second coil group 31a2 and the third coil group 31a3 in the second wiring sublayer 3121 b are disconnected, the third coil group 31a3 and the fourth coil group 31a4 in the second wiring sublayer 3121 b are disconnected, the fourth coil group 31a4 and the fifth coil group 31a5 in the second wiring sublayer 3121 b are disconnected, the fifth coil group 31a5 and the sixth coil group 31a6 in the second wiring sublayer 3121 b are disconnected, the sixth coil group 31a6 and the seventh coil group 31a7 in the second wiring sublayer 3121 b are disconnected, and the seventh coil group 31a7 and the eighth coil group 31a8 in the second wiring sublayer 3121 b are disconnected. The M-strand wire 311 a of the eighth coil group 31a8 passes through the disconnected area (such as the JJ area in FIG. 19 b ) and is connected to the second end D2.

[0151] That is, in this example, among the eight coil groups 31 a (the number of turns of the coil structure 31 is eight), eight internal coil groups 31 a (ie, two turns) are arranged on both sides.

[0152] In the four examples above, the double-sided routing of the L-group internal coil assemblies 31a disperses the current density within the L-group internal coil assemblies 31a across two layers, improving current distribution uniformity. Furthermore, each strand of wire 311a in the coil structure 31 is independently routed. The wires 311a of multiple coil assemblies 31a on a single layer have the same number of strands and are connected sequentially. This avoids the problem of eddy current losses caused by merging two wires 311a and then connecting them to an adjacent wire 311a when the wires 311a of different coil assemblies 31a have different strands. When L is less than N, the (NL)-group external coil assemblies 31a are connected in series, eliminating the need for a conductive structure between the upper and lower layers, simplifying the winding process of the coil structure 31. In addition, the coil structure 31 of the present application adopts a method in which each internal coil group 31a of the L group of internal coil groups 31a close to the center is wound in parallel on two wiring sub-layers 3121, and each external coil group 31a of the (NL) group of external coil groups 31a away from the center is wound in series on a single layer, so that the coil structure 31 has a smaller impedance when the thickness is less than or equal to 0.2 mm.

[0153] Furthermore, because the smaller the number of coil turns, the lower the coil impedance, the less heat the coil generates. Furthermore, because wireless charging generates an alternating magnetic field, this alternating magnetic field can generate eddy current losses on the metal structures (PCB, PCB bracket, battery, midframe, etc.) in the wireless charging receiving device, thereby generating heat. As the number of coil turns increases, the eddy current losses generated by the magnetic field on the PCB, PCB bracket, battery, midframe, etc. generally decrease, reducing the heat generated on the metal structures. Therefore, the present application sets the coil structure 31 to have an outer diameter d1 less than or equal to 52 mm and greater than or equal to 46 mm, such as 50 mm; an inner diameter d2 less than or equal to 28 mm and less than or equal to 16 mm, and a number of turns of 8. With the thinning of the coil, the sum of the coil losses and the metal eddy current losses in the wireless charging receiving device is minimized, that is, the overall heat of the wireless charging receiving device is minimized, and correspondingly, the losses are minimized, thereby enabling the coil structure 30 to achieve both high-power and high-freedom wireless charging.

[0154] It should be noted that the embodiments of the present application are described using the example of the coil structure 31 having 8 turns. Similar effects are achieved when the coil structure 31 has 7.5 turns or 8.5 turns, which will not be described in detail here.

[0155] In order to better illustrate this effect, a simulation test was conducted on the coil structure provided in the embodiment of the present application. The simulation test results are shown in Table 1, where the values ​​corresponding to the number of coil turns, transmitting side current (Itx), frequency (freq), and load are operating parameters, and the values ​​corresponding to the middle frame, main board, ..., TX aluminum plate, etc. are loss values.

[0156] Table 1 Comparison of losses at different turns

[0157] As shown in Table 1, when the number of turns of coil structure 31 is 8, although the impedance of coil structure 31 is relatively high, the sum of the eddy current losses generated by the magnetic field on the PCB board, PCB bracket, battery, metal (such as nanocrystals) within coil structure 31, coil, middle frame, etc. is relatively small. Therefore, the overall loss of the wireless charging receiving device is minimized. Therefore, it can be concluded that by setting the outer diameter d1 of coil structure 31 to be less than or equal to 52mm and greater than or equal to 46mm, such as 50mm; the inner diameter d2 of the coil to be less than or equal to 28mm and less than or equal to 16mm, and the number of turns of coil structure 31 to 8, the coil structure 30 can achieve high power while being thinned (the thickness can be less than or equal to 0.2mm).

[0158] It is known to those skilled in the art that the higher the mutual inductance between the receiving coil and the transmitting coil, the higher the charging efficiency. Referring to Figure 20, Figure 20 is a comparison diagram of the mutual inductance between the receiving coil and the transmitting coil when the number of turns of the coil structure is different in the embodiment of the present application. In Figure 20, the horizontal axis is the offset distance between the receiving coil and the transmitting coil, the unit is mm, and the vertical axis is the mutual inductance value, the unit is μH. Curve ① represents the mutual inductance value when the number of turns of the coil structure 31 is 8 turns, and curve ② represents the mutual inductance value when the number of turns of the coil structure 31 is 7 turns. As shown in Figure 20, the number of turns of the coil structure 31 is 7 turns: when the receiving coil and the transmitting coil are facing each other, the mutual inductance value is about 5μH; when the receiving coil and the transmitting coil are offset, the mutual inductance value decreases, and as the offset increases, the mutual inductance value decreases more. Coil structure 31 has eight turns: when the receiving coil and the transmitting coil are facing each other, the mutual inductance is approximately 7 μH, which is greater than the mutual inductance when coil structure 31 has seven turns and faces each other. When the receiving coil and the transmitting coil are offset, the mutual inductance decreases, and the mutual inductance decreases more as the offset increases. However, when the offset distance between the receiving coil and the transmitting coil is the same, the mutual inductance when coil structure 31 has eight turns is greater than the mutual inductance when coil structure 31 has seven turns. In other words, when coil structure 31 has eight turns, even if the receiving coil and the transmitting coil are offset, the mutual inductance between the receiving coil and the transmitting coil remains high. Therefore, it can be concluded that coil structure 30 also takes into account the effect of high-degree-of-freedom wireless charging.

[0159] In some embodiments, the width d3 of each wire 311 a in the L internal coil groups 31 a is less than or equal to 0.6 mm and greater than or equal to 0.3 mm.

[0160] This design is based on the fact that the magnetic field strength within coil structure 31 is strong, and the current density is unevenly distributed. Excessively wide traces increase eddy current losses. However, due to the thin conductors in the FPC coils used in this application, eddy current losses are already reduced. Therefore, traces with a width less than 0.3mm are meaningless. Therefore, when the width d3 of each conductor within coil assembly 31a within group L is less than or equal to 0.6mm and greater than or equal to 0.3mm, eddy current losses are reduced, further improving charging performance.

[0161] In some embodiments, the arrangement order of the M strands of conductive wire 311a in the radial direction of the coil structure 31 of at least one coil group 10 within the L internal coil groups 31a is altered, such that the conductive wires 311a closer to the center of the coil structure 31 in one internal coil group 31a are moved outward (away from the center of the coil structure 31), while the conductive wires 311a farther from the center of the coil structure 31 are moved inward. Within one internal coil group 31a, the conductive wires 311a radially located on either side have a higher current density, while the conductive wire 311a in the center has a lower current density. By varying the radial position of the M strands of conductive wire 311a, the current density within the M strands of conductive wire 311a is varied, thereby improving the uniformity of current distribution across the multiple conductive wires 311a within the coil group 31a.

[0162] The M strands of wire 311 a in one internal coil group 31 a are evenly distributed in two wiring sub-layers 3121 , and the arrangement order of the M strands of wire 311 a in the radial direction is reversed by crossing.

[0163] Referring to FIG. 21 , FIG. 21 is a simplified diagram of a crossover structure of different strands of conductive wire in the same coil assembly provided in an embodiment of the present application, FIG. 22 is a schematic diagram of the crossover structure shown in FIG. FIG. 23 is a cross-sectional view of FIG. 22 along the OO' direction. As shown in FIG. 21-23 , in an internal coil assembly 31a , the number of strands of conductive wire 311a is three, and the three strands of conductive wire 311a are divided into a first conductive wire 311a1 , a second conductive wire 311a2 , and a third conductive wire 311a3 . Since the three strands of conductive wire 311a in an internal coil assembly 31a are evenly distributed across two wiring sublayers 3121 , the first wiring sublayer 3121a and the second wiring sublayer 3121b are each provided with a first conductive wire 311a1 , a second conductive wire 311a2 , and a third conductive wire 311a3 , and are electrically connected to each other. For the sake of distinction, the first conductive wire 311a1 of the first wiring sublayer 3121a is abbreviated as 311a1-1, the second conductive wire 311a2 of the first wiring sublayer 3121a is abbreviated as the second conductive wire 311a2-1, and the third conductive wire 311a3 of the first wiring sublayer 3121a is abbreviated as the third conductive wire 311a3-1; the first conductive wire 311a1 of the second wiring sublayer 3121b is abbreviated as 311a1-2, the second conductive wire 311a2 of the second wiring sublayer 3121b is abbreviated as the second conductive wire 311a2-2, and the third conductive wire 311a3 of the second wiring sublayer 3121b is abbreviated as the third conductive wire 311a3-2.

[0164] In the radial direction, the first conductive wire 311a1 and the third conductive wire 311a3 are located on either side of the second conductive wire 311a2. The coil structure 31 includes a predetermined intersection region, the specific location of which can be selected by those skilled in the art based on practical circumstances. The first conductive wire 311a1-1 of the first wiring sublayer 3121a and the third conductive wire 311a3-2 of the second wiring sublayer 3121b intersect at the predetermined intersection region, and the first conductive wire 311a1-2 of the second wiring sublayer 3121b is disconnected at the predetermined intersection region. Furthermore, the third conductive wire 311a3-1 of the first wiring sublayer 3121b is disconnected at the predetermined intersection region. The second wire 311a2-1 of the first wiring sublayer 3121a and the second wire 311a2-2 of the second wiring sublayer 3121b are disconnected in a preset intersection area, and the disconnected part of the second wire 311a2-1 of the first wiring sublayer 3121a and the disconnected part of the second wire 311a2-2 of the second wiring sublayer 3121b overlap on the reference plane, and the disconnected part of the second wire 311a2-1 of the first wiring sublayer 3121a and the disconnected part of the second wire 311a2-2 of the second wiring sublayer 3121b are electrically connected through the connecting structure 31221 in the via hole of the insulating sublayer 3122, wherein the reference plane is a plane parallel to the plane where the magnetic conductive layer 32 is located.

[0165] Referring to Figures 24, 25, 26, 27, and 28, Figure 24 is a simplified diagram of another cross-structure of different strands of conductive wire within the same coil assembly according to an embodiment of the present application. Figure 25 is an enlarged view of the KK region in Figure 8a, Figure 26 is an enlarged view of the MM region in Figure 8b, Figure 27 is an enlarged view of the LL region in Figure 8a, and Figure 28 is an enlarged view of the NN region in Figure 8b. As shown in Figures 24, 25, 26, 27, and 28, within an internal coil assembly 31a, the number of strands of conductive wire 311a is four, and the four strands of conductive wire 311a are divided into a first conductive wire 311a1, a second conductive wire 311a2, a third conductive wire 311a3, and a fourth conductive wire 311a4. Since the four wires 311a in one internal coil group 31a are evenly distributed in two wiring sub-layers 3121, the first wiring sub-layer 3121a and the second wiring sub-layer 3121b are both provided with a first wire 311a1, a second wire 311a2, a third wire 311a3 and a fourth wire 311a4, which are electrically connected respectively. For the sake of distinction, the first conductive wire 311a1 of the first wiring sublayer 3121a is abbreviated as 311a1-1, the second conductive wire 311a2 of the first wiring sublayer 3121a is abbreviated as the second conductive wire 311a2-1, the third conductive wire 311a3 of the first wiring sublayer 3121a is abbreviated as the third conductive wire 311a3-1, and the fourth conductive wire 311a4 of the first wiring sublayer 3121a is abbreviated as the third conductive wire 311a4-1; the first conductive wire 311a1 of the second wiring sublayer 3121b is abbreviated as 311a1-2, the second conductive wire 311a2 of the second wiring sublayer 3121b is abbreviated as the second conductive wire 311a2-2, the third conductive wire 311a3 of the second wiring sublayer 3121b is abbreviated as the third conductive wire 311a3-2, and the fourth conductive wire 311a4 of the second wiring sublayer 3121b is abbreviated as the fourth conductive wire 311a4-2.

[0166] The coil structure 31 includes two predetermined intersection regions: a first predetermined intersection region and a second predetermined intersection region. Those skilled in the art can select the specific locations of the first predetermined intersection region and the second predetermined intersection region based on practical needs. Continuing with Figures 25 and 26 , the four strands of wire 311a are wound around the first predetermined intersection region, with the first wire 311a1, the second wire 311a2, the third wire 311a3, and the fourth wire 311a4 arranged in sequence radially away from the center of the coil structure 31. When the four strands of wire 311a are wound to the first predetermined intersection region, the first wire 311a1-1 of the first wiring sublayer 3121a and the second wire 311a2-2 of the second wiring sublayer 3121b cross in the first predetermined intersection region, and the first wire 311a1-2 of the second wiring sublayer 3121b is disconnected at the first predetermined intersection region, and the second wire 311a2-1 of the first wiring sublayer 3121b is disconnected at the first predetermined intersection region; the third wire 311a3-1 of the first wiring sublayer 3121a and the fourth wire 311a4-2 of the second wiring sublayer 3121b are disconnected at the first predetermined intersection region. Assume that the crossing areas are crossed, and the third wire 311a3-2 of the second wiring sublayer 3121b is disconnected at the first preset crossing area, and the fourth wire 311a4-1 of the first wiring sublayer 3121b is disconnected at the first preset crossing area. At this time, along the radial direction and away from the center of the coil structure 31, the arrangement of the four wires 311a is changed from the first wire 311a1, the second wire 311a2, the third wire 311a3 and the fourth wire 311a4 arranged in sequence to the second wire 311a2, the first wire 311a1, the fourth wire 311a4 and the third wire 311a3 arranged in sequence. Continuing to refer to Figures 27 and 28, when the four strands of wire 311a in this arrangement order (the second wire 311a2, the first wire 311a1, the fourth wire 311a4 and the third wire 311a3 are arranged in sequence radially and away from the center of the coil structure 31) are wound to the second preset intersection area, the third wire 311a3-1, the fourth wire 311a4-1 of the first wiring sublayer 3121a and the first wire 311a1-2, the second wire 311a2-2 of the second wiring sublayer 3121b cross in the second preset intersection area, and the third wire 311a3-2 and the fourth wire 311a4-2 of the second wiring sublayer 3121b are disconnected at the second preset intersection area, and the first wire 311a1 and the second wire 311a2-1 of the first wiring sublayer 3121b are disconnected at the second preset intersection area. At this time, along the radial direction and away from the center of the coil structure 31, the arrangement of the four wires 311a changes from the second wire 311a2, the first wire 311a1, the fourth wire 311a4 and the third wire 311a3 arranged in sequence to the fourth wire 311a4, the third wire 311a3, the second wire 311a2 and the first wire 311a1 arranged in sequence.

[0167] Referring to Figure 29 , Figure 29 is a simplified diagram of another cross-structure of different strands of wire within the same coil assembly provided in an embodiment of the present application. As shown in Figure 29 , within an internal coil assembly 31a , the number of strands of wire 311a is five, with the five strands 311a being divided into a first wire 311a1, a second wire 311a2, a third wire 311a3, a fourth wire 311a4, and a fifth wire 311a4. Because the five strands of wire 311a within an internal coil assembly 31a are evenly distributed across two wiring sublayers 3121 , the first wiring sublayer 3121a and the second wiring sublayer 3121b are each provided with a first wire 311a1, a second wire 311a2, a third wire 311a3, a fourth wire 311a4, and a fifth wire 311a4, and are electrically connected to each other.

[0168] The coil structure 31 includes two predetermined intersection regions, namely a first predetermined intersection region and a second predetermined intersection region. The specific locations of the first predetermined intersection region and the second predetermined intersection region can be selected by those skilled in the art based on practical circumstances. At the first predetermined intersection region, the first conductor 311a1 and the second conductor 311a2 are interchanged, and the fourth conductor 311a4 and the fifth conductor 311a4 are interchanged. The arrangement of the remaining third conductor 311a3 remains unchanged. At this point, radially away from the center of the coil structure 31, the arrangement of the five conductors 311a changes from the first conductor 311a1, the second conductor 311a2, the third conductor 311a3, the fourth conductor 311a4, and the fifth conductor 311a5 to the second conductor 311a2, the first conductor 311a1, the third conductor 311a3, the fifth conductor 311a5, and the fourth conductor 311a4. At the second predetermined intersection region, the order of the intersection group consisting of the first and second conductors 311a1 and 311a2 is swapped with the order of the intersection group consisting of the fourth and fifth conductors 311a4. The order of the remaining third conductor 311a3 remains unchanged. At this time, in the radial direction away from the center of the coil structure 31, the arrangement of the five conductors 311a changes from the second conductor 311a2, the first conductor 311a1, the third conductor 311a3, the fifth conductor 311a5, and the fourth conductor 311a4 to the fifth conductor 311a5, the fourth conductor 311a4, the third conductor 311a3, the second conductor 311a2, and the first conductor 311a1. The specific intersection principle is similar to that described above and can be found in the above description, so this will not be repeated here.

[0169] In summary, when the thickness of the coil module provided in this application is less than or equal to 0.2 mm, by reasonably setting the coil module, such as selecting the appropriate number of coil turns, number of coil strands, coil diameter and wire arrangement, the effects of high-power and high-freedom wireless charging can be achieved.

[0170] The beneficial effects are described in detail below through comparative examples.

[0171] Table 2 Comparison of 50W high-power charging

[0172] The losses of each structure of the wireless charging system using the coil structure of the present application (0.2 mm thickness, and using the number of coil turns, number of coil strands, coil diameter and wire arrangement in the embodiment of the present application) and the wire charging system using the coil structure of the prior art (such as 0.3 mm thickness) were simulated and tested. The simulation test results are shown in Table 2.

[0173] From the values ​​corresponding to the RX coil (i.e., the receiving coil) in Table 2, it can be seen that the coil structure of the present application is only 0.2mm thick and the coil impedance is 230mΩ, which is greater than the impedance of the 0.3mm coil of the comparative solution (impedance 110mΩ). The coil structure of the present application generates higher heat (e.g., up to 2.1W). However, from the values ​​corresponding to the surrounding metal in Table 2, it can be seen that the coil structure of the present application can effectively reduce the metal eddy current loss through the appropriate number of coil turns, number of coil strands, coil diameter, and wire arrangement. Among them, the eddy current loss of the present application is only 856.14mW, which is 746.32mW lower than the comparative solution, which is a significant advantage. At the same time, from the values ​​corresponding to the transmitting side (TX) in Table 2, it can be seen that the coil structure of the present application also reduces the coil current on the transmitting side (under a load of 50W, the present application is 3.7A, and the comparative solution is 4A), thereby bringing lower transmission loss, lower transmission heat, and reducing the current pressure on the transmitting side. The transmitting side has a higher margin to support wireless charging after offset, thereby bringing greater charging freedom. In addition, the corresponding values ​​of the heat generation summary of the mobile phone (wireless charging receiving device) and the heat generation summary of the transmitter side in Table 2 show that the mobile phone side loss of this application is 158.94mW lower than that of the comparative solution; the transmitter side loss of this application is 1032.69mW lower than that of the comparative solution. In summary, the coil structure solution provided by this application has a charging efficiency that is 1.34% higher than that of the comparative solution (83.80% for this application and 82.46% for the comparative solution).

[0174] Therefore, through simulation tests, it can be seen that the coil structure provided in the embodiment of the present application takes into account the effects of lightweight, high-power and high-freedom wireless charging.

[0175] Those skilled in the art will understand that, in actual settings, the above-mentioned values ​​will vary. In this case, those skilled in the art will foresee that the coil structure scheme in the embodiment of the present application is superior to the coil structure scheme in the prior art.

[0176] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above 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 The coil module operates in a magnetic coupling wireless charging system with a frequency less than or equal to 500 Khz. The coil module includes: a coil structure; the coil structure is a toroidal coil. The thickness of the coil structure is less than or equal to 0.175 mm and greater than or equal to 0.07 mm. The outer diameter of the coil of the coil structure is less than or equal to 52 mm and greater than or equal to 46 mm, and the inner diameter of the coil of the coil structure is less than or equal to 28 mm and less than or equal to 16 mm. The inductance of the coil module is less than or equal to 6 μH and greater than or equal to 4 μH.

2. The coil module according to claim 1, wherein, The coil structure includes a functional layer. Along the thickness direction of the coil structure, the functional layer includes a first wiring sub-layer and a second wiring sub-layer, and also includes an insulator layer located between the first wiring sub-layer and the second wiring sub-layer; through holes are formed in the insulator layer, and connection structures are arranged in the through holes for electrically connecting the first wiring sub-layer and the second wiring sub-layer.

3. The coil module according to claim 2, characterized in that, The coil structure includes N groups of coil groups; the N groups of coil groups include L groups of internal coil groups, where N is less than or equal to 8.5 and greater than or equal to 7.5; L is less than or equal to N. The L groups of internal coil groups are wound successively along the radial direction. Both the first wiring sub-layer and the second wiring sub-layer are wound with L groups of internal coil groups, and the L groups of internal coil groups of the first wiring sub-layer and the L groups of internal coil groups of the second wiring sub-layer are respectively electrically connected.

4. The coil module according to claim 3, wherein When L is less than N, the N groups of coil groups further include (N - L) groups of external coil groups arranged around the L groups of internal coil groups. (N - L) / 2 groups of the (N - L) groups of external coil groups are wound on the first wiring sub-layer and are connected in series with the L groups of internal coil groups of the first wiring sub-layer, and the remaining (N - L) / 2 groups of external coil groups are wound on the second wiring sub-layer and are connected in series with the L groups of internal coil groups of the second wiring sub-layer, so that the N groups of coil groups are connected in series successively.

5. The coil module according to claim 4, wherein N is 8.

6. The coil module according to claim 5, wherein L is 2, 4, 6 or 8.

7. The coil module according to claim 3, wherein Each group of coil groups includes M strands of wires, where M is less than or equal to 5 and greater than or equal to 3.

8. The coil module according to claim 7, wherein Along the radial direction, in the internal coil group, the width of each strand of wire is less than or equal to 0.6 mm and greater than or equal to 0.3 mm.

9. The coil module according to claim 7, wherein The arrangement order of the M strands of wires in at least one group of the L groups of internal coil groups changes along the radial direction.

10. The coil module according to claim 9, wherein M is 3; the 3 strands of wires are respectively a first wire, a second wire and a third wire; along the radial direction, the first wire and the third wire are located on both sides of the second wire. The coil structure includes a preset crossing area, where the first wire of the first wiring sub-layer and the third wire of the second wiring sub-layer cross in the preset crossing area, and the first wire of the second wiring sub-layer is disconnected at the preset crossing area, and the third wire of the first wiring sub-layer is disconnected at the preset crossing area. The second wire of the first wiring sub-layer and the second wire of the second wiring sub-layer are disconnected at the preset crossing area, and the disconnected part of the second wire of the first wiring sub-layer overlaps with the disconnected part of the second wire of the second wiring sub-layer in a reference plane. The disconnected part of the second wire of the first wiring sub-layer and the disconnected part of the second wire of the second wiring sub-layer are electrically connected through the connection structure in the insulator layer via hole, where the reference plane is a plane perpendicular to the thickness direction of the coil structure.

11. The coil module according to claim 9, characterized in that, M is 4; the four wires are the first wire, the second wire, the third wire, and the fourth wire respectively; The coil structure includes a first preset crossing area and a second preset crossing area; before the four wires are wound to the first preset crossing area, along the radial direction and away from the center of the coil structure, the first wire, the second wire, the third wire, and the fourth wire are arranged in sequence. When the four wires are wound to the first preset crossing area, the first wire of the first wiring sub-layer and the second wire of the second wiring sub-layer cross in the first preset crossing area, and the first wire of the second wiring sub-layer is disconnected at the first preset crossing area, and the second wire of the first wiring sub-layer is disconnected at the first preset crossing area; the third wire of the first wiring sub-layer and the fourth wire of the second wiring sub-layer cross in the first preset crossing area, and the third wire of the second wiring sub-layer is disconnected at the first preset crossing area, and the fourth wire of the first wiring sub-layer is disconnected at the first preset crossing area; When the four wires are wound to the second preset crossing area, the third wire, the fourth wire of the first wiring sub-layer and the first wire, the second wire of the second wiring sub-layer cross in the second preset crossing area, and the third wire and the fourth wire of the second wiring sub-layer are disconnected at the second preset crossing area, and the first wire and the second wire of the first wiring sub-layer are disconnected at the second preset crossing area.

12. The coil module according to claim 9, wherein M is 5; the five wires are divided into the first wire, the second wire, the third wire, the fourth wire, and the fifth wire; The coil structure includes a first preset crossing area and a second preset crossing area; At the first preset crossing area, the first wire and the second wire exchange their orders, the fourth wire and the fifth wire exchange their arrangement orders, and the arrangement order of the remaining third wire remains unchanged; At the second preset crossover region, the arrangement order of the crossover group formed by the first wire and the second wire and the crossover group formed by the fourth wire and the fifth wire is interchanged, and the arrangement order of the remaining third wire remains unchanged.

13. The coil module according to claim 9, characterized in that, The coil module further includes: a magnetic conductive layer; a double-sided adhesive layer is provided between the magnetic conductive layer and the coil structure; Along the thickness direction of the coil structure, the magnetic conductive layer includes two insulator layers and a magnetic conductive sub-layer located between the two insulator layers; An insulating layer in the magnetic conductive layer that contacts the coil structure is provided with a hollowed-out portion, and the hollowed-out portion exposes the magnetic conductive sub-layer. The double-sided adhesive layer is located in the hollowed-out portion and contacts the magnetic conductive sub-layer.

14. The coil module according to any one of claims 1-13, characterized in that, The coil structure is an FPC coil.

15. A wireless charging receiving device, characterized in that, Including the coil module according to any one of claims 1-14.

16. A wireless charging system, characterized in that, Including: A wireless charging transmitting device and at least one wireless charging receiving device according to claim 15, wherein the wireless charging transmitting device is configured to perform wireless charging for the wireless charging receiving device.

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