Coil module, wireless charging receiving equipment and wireless charging system

Abstract

The embodiment of the invention provides a coil module, wireless charging receiving equipment and a wireless charging system, relates to the technical field of wireless charging, and can give consideration to the effects of lightness, thinness, high power and high-degree-of-freedom wireless charging at the same time. The coil module works in a magnetic coupling wireless charging system of which the frequency is less than or equal to 500Khz. The coil module comprises a coil structure and a coil structure, the coil structure is an annular 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 a coil of the coil structure is smaller than or equal to 52 mm and larger than or equal to 46 mm, and the inner diameter of the coil of the coil structure is smaller than or equal to 28 mm and smaller than or equal to 16 mm. The inductance value of the coil module is less than or equal to 6 [mu] H and greater than or equal to 4 [mu] H.

Description

Technical Field

[0001] This application relates to the field of wireless charging technologies, and particularly to a coil module, a wireless charging receiving device, and a wireless charging system. Background Art

[0002] Due to the fact that the wireless charging method is safer, more reliable, and more convenient to use than the wired charging method, more and more electronic devices, such as mobile phones, tablet computers, smart watches, etc., have adopted wireless charging technologies.

[0003] Existing wireless charging technologies generally use 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.

[0004] However, with the continuous thinning of electronic devices, the space that the receiving coil can occupy inside the electronic device is getting smaller and smaller. Ensuring a high charging efficiency in the continuously shrinking space is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0005] In order to solve the above technical problems, this application provides a coil module, a wireless charging receiving device, and a wireless charging system, which can bring users a high-power and high-degree-of-freedom wireless charging experience in the case of the continuous thinning of electronic devices.

[0006] In a first aspect, an embodiment of this application provides a coil module. 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 an annular 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.

[0007] This application sets the outer diameter d1 of the coil of the coil structure to be less than or equal to 52 mm and greater than or equal to 46 mm; the inner diameter d2 of the coil to be less than or equal to 28 mm and less than or equal to 16 mm. In the case of thinning the 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 sum of the losses of the coil 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 to take into account the effects of thinning, high power, and high-degree-of-freedom wireless charging.

[0008] 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, it is 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.

[0009] 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.

[0010] 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 sub-layer and a second wiring sub-layer. The functional layer further 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.

[0011] In this way, part of the coil groups in the coil structure can have double-sided wiring. On the premise of a relatively thin thickness, the current density in part of the coil groups can be dispersed on two layers, improving the current distribution uniformity.

[0012] According to the first aspect, or any one of the above implementation manners of the first aspect, 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 sequentially along the radial direction, and 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 electrically connected correspondingly.

[0013] Since the magnetic field intensity inside the coil structure is relatively strong and the current density distribution is uneven, setting the internal coil groups to have double-sided wiring can disperse the current density in the internal coil groups on two layers, improving the current distribution uniformity.

[0014] According to the first aspect, or any one of the above implementation manners of the first aspect, 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; 2 / (N - L) 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 2 / (N - L) 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 in sequence.

[0015] When L is less than N, (N - L) groups of external coil groups are connected in series, and there is no need to make a conductive structure between the upper and lower layers, which simplifies the winding process of the coil structure. In addition, the coil structure of the present application adopts a method in which each of the L groups of internal coil groups near the center is wound in parallel on two wiring sub-layers, and each of the (N - L) groups of external coil groups far from the center is wound in series on a single layer. When the thickness of the coil structure is less than or equal to 0.2 mm, it has a small impedance.

[0016] According to the first aspect, or any one of the implementation manners of the above first aspect, N is 8. The number of turns of the coil structure 31 is 8 turns. In the case of thinning the coil, the sum of the loss of the coil 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. Correspondingly, the loss is minimized, and further, the coil structure takes into account the effects of high-power and high-degree-of-freedom wireless charging.

[0017] According to the first aspect, or any one of the implementation manners of the above first aspect, L is 2, 4, 6, or 8.

[0018] According to the first aspect, or any one of the implementation manners of the above first aspect, each of the coil groups includes M strands of wires, where M can be less than or equal to 5 and greater than or equal to 3.

[0019] Each strand of wire in the coil structure runs independently. The number of strands of wires in multiple coil groups on a single layer is the same and are connected in sequence, avoiding the problem of eddy current loss caused by the need to connect two wires and then connect to an adjacent wire when the number of strands of wires in different coil groups is different. In addition, setting M to be less than or equal to 5 and greater than or equal to 3 is because the outer diameter of the coil of the toroidal coil is less than or equal to 52 mm and greater than or equal to 46 mm; the inner diameter of the coil is less than or equal to 28 mm and less than or equal to 16 mm, that is, the area of the wire 311a is limited. In a limited area, the impedance of the wiring sub-layer will not increase due to more gaps between adjacent strands of wires when the number of strands of wires is large, nor will the current transmission be affected due to fewer current-carrying channels caused by the skin effect when the number of strands of wires is small.

[0020] According to the first aspect, or any one of the implementation manners of the above first aspect, 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.

[0021] The magnetic field intensity inside the coil structure is strong, and the current density distribution is uneven. When the width of each strand of wire in the L groups of internal coil groups is less than or equal to 0.6 mm and greater than or equal to 0.3 mm, the eddy current loss is low, further improving the charging effect.

[0022] According to the first aspect, or any implementation of the above first aspect, the radial arrangement order of M wires in at least one of the L groups of the internal coil groups is changed.

[0023] The radial arrangement order of the wires in the coil group is changed so that the wires close to the center of the coil structure move outward, and the wires far from the center of the coil structure move inward. In the same internal coil group, the current density of the wires located on both sides in the radial direction is large, and the current density of the middle wire is small. By changing the position of the wires in the radial direction, the current density in the wires is changed, and the uniformity of the current distribution of multiple wires in the internal coil group is improved.

[0024] According to the first aspect, or any implementation of the above first aspect, M is 3; the three wires are the first wire, the second wire, and the third wire respectively; in 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 crossover area, the first wire of the first wiring sub-layer and the third wire of the second wiring sub-layer cross in the preset crossover area, and the first wire of the second wiring sub-layer is disconnected at the preset crossover area, and the third wire of the first wiring sub-layer is disconnected at the preset crossover 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 crossover 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 the reference plane, and 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.

[0025] Exemplarily, the reference plane is also parallel to the plane where the magnetic conductive layer is located.

[0026] When M is 3, through the set crossover rule, in each internal coil group, the multiple wires are changed from sequential arrangement to reverse arrangement in the radial direction, so that the wires on both sides pass through the middle position and finally exchange positions, improving the uniformity of the current distribution.

[0027] According to the first aspect, or any implementation of the above first aspect, M is 4; the four wires are the first wire, the second wire, the third wire, and the fourth wire; 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.

[0028] When M is 4, through the set crossing rule, in each internal coil group, multiple wires 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 finally exchange, improving the current distribution uniformity.

[0029] According to the first aspect, or any implementation of the above first aspect, M is 5; the five wires are 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, and 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 crossing area, the crossing group composed of the first wire and the second wire and the crossing group composed of the fourth wire and the fifth wire exchange their arrangement orders, and the arrangement order of the remaining third wire remains unchanged.

[0030] When M is 5, through the set crossing rule, in each internal coil group, multiple wires 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 finally exchange, improving the current distribution uniformity.

[0031] According to the first aspect, or any implementation of the above first aspect, the coil module further includes: a magnetic conductive layer; a double-sided adhesive layer is disposed 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; the insulator layer in the magnetic conductive layer that contacts the coil structure is provided with a hollowed-out portion, and the hollowed-out portion can expose the magnetic conductive sub-layer, and the double-sided adhesive layer is located in the hollowed-out portion and contacts the magnetic conductive sub-layer. To further reduce the thickness of the coil module.

[0032] According to the first aspect, or any implementation of the above first aspect, the coil structure is an FPC coil. The FPC coil has good flatness. In this way, a relatively thin double-sided adhesive layer can be used to firmly bond the magnetic conductive layer and the coil structure, which is beneficial to the thin and light design of the device using this coil module.

[0033] 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 aspect.

[0034] The second aspect corresponds to the first aspect and any implementation of the first aspect. The technical effects corresponding to the second aspect can refer to the technical effects corresponding to the first aspect and any implementation of the first aspect above, and will not be elaborated here.

[0035] In a third aspect, an embodiment of the present application provides a wireless charging system, which includes: a wireless charging transmitting device and the wireless charging receiving device of the second aspect, and the wireless charging transmitting device is used to wirelessly charge the wireless charging receiving device.

[0036] The third aspect corresponds to the second aspect and any implementation of the second aspect. The technical effects corresponding to the third aspect and any implementation of the third aspect can refer to the technical effects corresponding to the second aspect and any implementation of the second aspect above, and will not be elaborated here. Description of the Drawings

[0037] Figure 1 It is a schematic structural diagram of a wireless charging system provided by an embodiment of the present application;

[0038] Figure 2 It is a schematic circuit diagram of a wireless charging system provided by an embodiment of the present application;

[0039] Figure 3 is Figure 1 a schematic structural diagram of the wireless charging receiving device shown;

[0040] Figure 4 It is a film layer structure diagram of a coil module provided by an embodiment of the present application;

[0041] Figure 5 Another film layer structure diagram of the coil module provided by the embodiment of the present application;

[0042] Figure 6a A front view structure diagram of a coil structure provided by the embodiment of the present application;

[0043] Figure 6b Another front view structure diagram of a coil structure provided by the embodiment of the present application;

[0044] Figure 7 is Figure 6a The sectional view of the coil shown along the AA' direction;

[0045] Figure 8a is Figure 6a The front view structure diagram of the first coil in the coil structure shown;

[0046] Figure 8b is Figure 6a The front view structure diagram of the second coil in the coil structure shown;

[0047] Figure 9 is Figure 8b The partial enlarged view of the BB area in;

[0048] Figure 10 Another front view structure diagram of a coil structure provided by the embodiment of the present application;

[0049] Figure 11 is Figure 10 The sectional view of the coil shown along the DD' direction;

[0050] Figure 12a is Figure 10 The front view structure diagram of the first wiring sub-layer in the coil structure shown;

[0051] Figure 12b is Figure 10 The front view structure diagram of the second wiring sub-layer in the coil structure shown;

[0052] Figure 13 is Figure 12b The partial enlarged view of the EE area in;

[0053] Figure 14 Another front view structure diagram of a coil structure provided by the embodiment of the present application;

[0054] Figure 15 is Figure 14 The sectional view of the coil shown along the GG' direction

[0055] Figure 16a is Figure 14Schematic diagram of the front structure of the first wiring sub-layer in the coil structure shown;

[0056] Figure 16b is Figure 14 Schematic diagram of the front structure of the second wiring sub-layer in the coil structure shown;

[0057] Figure 17 Schematic diagram of the front structure of another coil structure provided by an embodiment of the present application;

[0058] Figure 18 is Figure 17 Cross-sectional view of the coil shown along the II’ direction;

[0059] Figure 19a is Figure 17 Schematic diagram of the front structure of the first wiring sub-layer in the coil structure shown;

[0060] Figure 19b is Figure 17 Schematic diagram of the front structure of the second wiring sub-layer in the coil structure shown;

[0061] Figure 20 Mutual inductance comparison diagram between the receiving coil and the transmitting coil when the number of turns of the coil structure in the embodiment of the present application is different;

[0062] Figure 21 Simplified diagram of a cross structure of different strands of wire in the same coil group provided by an embodiment of the present application;

[0063] Figure 22 is Figure 21 Schematic diagram of the principle of the cross structure shown;

[0064] Figure 23 is Figure 22 Cross-sectional view along the OO’ direction;

[0065] Figure 24 Simplified diagram of another cross structure of different strands of wire in the same coil group provided by an embodiment of the present application;

[0066] Figure 25 is Figure 8a Enlarged view of the KK area in;

[0067] Figure 26 is Figure 8b Enlarged view of the MM area in;

[0068] Figure 27 is Figure 8a Enlarged view of the LL area in;

[0069] Figure 28 is Figure 8b Enlarged view of the NN area in;

[0070] Figure 29 Another schematic diagram of the cross - structure of different strands of wire in the same coil group provided by the embodiments of the present application. Detailed implementation manners

[0071] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0072] The term "and / or" in this article is merely a description of the associated relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0073] The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects, rather than to describe a specific order of the objects. For example, the first target object and the second target object are used to distinguish different target objects, rather than to describe the specific order of the target objects.

[0074] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific manner.

[0075] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality of" refers to two or more. For example, a plurality of processing units refers to two or more processing units; a plurality of systems refers to two or more systems.

[0076] First, the terms related to the present application are explained:

[0077] The layer refers to the number of planes in which the wires included in the coil provided by the present application are arranged. When all the wires included in a coil are wound on the same plane to form a planar coil, the coil is a single - layer wound coil; when all the wires included in a coil are not arranged on one plane, for example, the first wire is wound on the first plane layer, the second wire is wound on the second plane layer, and the first wire and the second wire are electrically connected through a via in the insulating layer between the first plane layer and the second plane layer, it indicates that the coil is a two - layer wound coil.

[0078] The number of turns refers to the number of loops of the wire winding in each coil. It should be noted that when any loop of the wire winding is distributed in two planar layers and is electrically connected through a via in the insulating layer between the two planar layers, it is still counted as 1 turn.

[0079] The number of strands refers to the number of parallel wires when the coil is wound.

[0080] Next, the technical scenario involved in the embodiments of the present application will be described.

[0081] The technical solution of the present application is applied to the wireless charging technical scenario. This 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 wireless charging function. For example, the wireless charging device can be a wireless charging mobile power supply, a wireless charging board, a wireless charger, etc., and the device to be charged can be a mobile phone, a tablet computer, a laptop computer, a personal digital assistant (PDA), an in-vehicle 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 devices to be charged can also be wireless charging electric vehicles, wireless charging household appliances (such as a floor cleaning robot, etc.), drones and other electronic products. Again, 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.

[0082] Among them, the above-mentioned wireless charging device can also be called a wireless charging transmitting device, and the device to be charged can also be called a wireless charging receiving device.

[0083] To enable those skilled in the art to better understand the technical solution provided by the embodiments of the present application, the wireless charging principle in the wireless charging technical scenario will be briefly introduced below. Among them, an example is given with the wireless charging transmitting device being a wireless charger and the wireless charging receiving device being a mobile phone, and in the following other contents, an example is also given with the wireless charging transmitting device being a wireless charger and the wireless charging receiving device being a mobile phone.

[0084] See Figure 1 , Figure 1 which is a schematic structural diagram of a wireless charging system provided by an embodiment of the present application. As Figure 1 shown, the wireless charging system 01 includes a wireless charging transmitting device 10 and a wireless charging receiving device 20. The wireless charging transmitting device 10 can be a wireless charger, the wireless charging receiving device 20 can be a mobile phone, and the wireless charger wirelessly charges the mobile phone.

[0085] It should be noted that Figure 1The shown wireless charger has a certain inclination so that the mobile phone can lean against and closely adhere to the wireless charger. Of course, this does not constitute a limitation to this application. In other alternative embodiments of this application, the wireless charger can also have other forms. For example, the wireless charger is in the shape of a tablet, and the wireless charger supports the mobile phone to be placed horizontally above it.

[0086] See Figure 2 , Figure 2 which is a schematic circuit diagram of a wireless charging system provided by an embodiment of this application. As Figure 2 shown, the wireless charging transmitting device 10 includes a power supply 11 and a wireless transmitting device 12.

[0087] The power supply 11 is used to provide a DC voltage. Among them, in order to distinguish it from other DC voltages, the DC voltage provided by the power supply 11 is the first DC voltage.

[0088] The wireless transmitting device 12 includes a direct current (DC) / alternating current (AC) circuit 122, a resonant capacitor C1, and a transmitting coil L1.

[0089] In some embodiments, the wireless transmitting device 12 further includes a voltage conversion circuit 121. The voltage conversion circuit 121 is electrically connected to the power supply 11 and is used to convert the first DC voltage output by the power supply 11 into a stable second DC voltage. Exemplarily, the voltage conversion circuit 121 can be a boost circuit (such as a boost circuit, a boost transformer, or a power amplifier, etc.) for boosting the first DC voltage output by the power supply 11 and then outputting it.

[0090] 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, improve the energy transfer ability of the system, and is beneficial to high-power transmission.

[0091] Of course, the voltage conversion circuit 121 is not limited to a boost circuit and can also be a buck circuit for bucking the first DC voltage output by the power supply 11 and then outputting it. Those skilled in the art can set the voltage conversion circuit 121 according to the actual situation.

[0092] The direct current (DC) / alternating current (AC) circuit 122 is electrically connected to the voltage conversion circuit 121 and is used to convert the second DC voltage output by the voltage conversion circuit 121 into an alternating current. Exemplarily, the DC / AC circuit 122 can be an inverter bridge (including an upper tube, a lower tube, and a digital module, etc.), and its circuit structure can be a full-bridge circuit or a half-bridge circuit. Among them, the DC / AC circuit 122 is also called a transmit (TX) chip.

[0093] The resonant capacitor C1 and the transmitting coil L1 are connected in series to form a series resonant network. The transmitting coil L1 is electrically connected to the DC / AC circuit 122 through the resonant capacitor C1. During the charging and discharging process of the DC / AC circuit 122 to the resonant capacitor C1 and the transmitting coil L1, the transmitting coil L1 can convert alternating current into an alternating magnetic field.

[0094] In addition, the wireless charging transmitting device 10 further includes structures such as a Printed Circuit Board (PCB) and a fan (not shown in the figure). Among them, the DC / AC circuit 122 and the resonant capacitor C1 in the wireless transmitting device 12 are arranged on the PCB to achieve electrical connection between the structures (signal transmission and interaction can be performed). The transmitting coil L1 can be electrically connected to the PCB through a coil connector (not shown in the figure), and further achieve electrical connection with the DC / AC circuit 122 and the resonant capacitor C1. The setting of the fan can reduce the heat generated when the wireless charging transmitting device 10 charges the wireless charging receiving device 20.

[0095] Combined Figure 3 , Figure 3 is Figure 1 a schematic structural diagram of the wireless charging receiving device shown. As Figure 3 shown, 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 respectively located on both sides of the middle frame 203. The housing 201, the display screen 202, and the middle frame 203 can enclose an accommodation cavity. Structures such as a PCB 204, a PCB bracket (not shown in the figure), a battery (including a battery cell, a long-side protection board, and a short-side protection board, etc.) 205, a flash 206, a rear camera 207, and a Near Field Communication (NFC) module (not shown in the figure) are arranged in the accommodation cavity. Among them, some devices are arranged on the PCB 204, and the PCB bracket can fix some devices on the PCB 204 and / or be used to carry some devices. In the embodiment of the present application, the PCB 204 includes a main board 2041 and a secondary board 2042. The rear camera 207 can be electrically connected to the main board 2041 through an FPC 208. The number of rear cameras 207 can be one or more. When the number of rear cameras 207 is multiple, the functions of the multiple rear cameras 207 can be different. For example, in a possible implementation manner, one of the rear cameras 207 is responsible for the main camera, one of the rear cameras 207 is responsible for zooming, and one of the rear cameras 207 is responsible for wide-angle, etc.

[0096] The mobile phone further includes a camera decoration member 209 for decorating the camera. A decoration hole 2011 is formed in the housing 201. The camera decoration member 209 is disposed at the decoration hole 2011, and the rear camera 207 is opposite to the camera decoration member 209.

[0097] Continue to refer to Figure 2 , 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-consuming unit at the back end of the system. The load 21 can be a battery or the like, or other devices that need to be charged.

[0098] The wireless receiving device 22 includes a receiving coil L2, a resonant capacitor C2, and an AC / DC circuit 222.

[0099] The receiving coil L2 is located in the accommodation cavity. Exemplarily, it can be located between the battery 205 and the housing 201. The receiving coil L2 is electrically connected to the PCB 204 through a coil connector (not shown in the figure).

[0100] The resonant capacitor C2 and the AC / DC circuit 222 are disposed on the PCB 204 (such as the main board 2041). The receiving coil L2 is electrically connected to the resonant capacitor C2 and the AC / DC circuit 222 through the PCB 204 (signal transmission and interaction can be performed). In addition, the AC / DC circuit 222 is also electrically connected to the battery 21.

[0101] When the wireless charging transmitting device 10 needs to charge the wireless charging receiving device 20, the receiving coil L2 approaches or fits 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 supply power to the load 21. Exemplarily, the AC / DC circuit 222 can be 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 Receive (RX) chip.

[0102] In some embodiments, when the direct current output by the AC / DC circuit 222 is too large and cannot be directly provided to the load 21, the wireless receiving device 22 may further include a voltage conversion circuit 221. The voltage conversion circuit 221 is electrically connected to the AC / DC circuit 222 and the load 21 respectively, and is used to reduce the larger voltage output by the AC / DC circuit 222 to the voltage required by the load 21. Exemplarily, the voltage conversion circuit 221 can be a buck circuit (also called a buck circuit).

[0103] In some embodiments, the voltage conversion circuit 221 may also be a switched capacitor (SC) circuit (not shown in the figure). The SC circuit can achieve step-down conversion with a ratio such as 2:1, 4:1, etc. For the specific structure of the SC circuit and the principle of achieving step-down conversion, reference can be made to the prior art.

[0104] 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 further includes a USB interface. The USB interface 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 into the charging signal required by the load 21 to supply power to the load 21. In some embodiments, an overvoltage protection (OVP) circuit is provided between the USB interface and the voltage conversion circuit 221. Among them, the OVP circuit may include an OVP switching tube, and the switching tube may be a MOS tube. When the OVP circuit detects that the voltage connected to the USB interface is too high (exceeding the threshold voltage), it can actively cut off the connection between the voltage conversion circuit 221 and the USB interface to protect the voltage conversion circuit 221.

[0105] The structure of the wireless charging system 01 has been introduced above. From the above content, it can be seen that the wireless charging system 01 transmits wireless power based on the magnetic coupling between the transmitting coil L1 and the receiving coil L2. When the electromagnetic coupling coefficient between the transmitting coil L1 and the receiving coil L2 is higher, the power transmission efficiency between the transmitting and receiving coils will be higher, and the charging efficiency will be faster. The electromagnetic coupling coefficient between the transmitting coil L1 and the receiving coil L2 is generally related to factors such as coil size, coil spacing, and alignment. For example, when the coil spacing between the transmitting and receiving coils and the alignment between the transmitting coil L1 and the receiving coil L2 are kept the same, when the thickness of the receiving coil is thicker, the impedance of the receiving coil decreases, the electromagnetic coupling coefficient between the transmitting coil and the receiving coil increases, and the power transmission efficiency between the transmitting and receiving coils will be higher, and the charging efficiency will be faster. However, when the coil is thicker, it is not conducive to the thin and light design of the electronic device, affecting the user's holding feel. That is to say, the existing wireless charging solutions cannot simultaneously take into account the problems of high charging efficiency and the thin and light electronic device with a receiving coil.

[0106] 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 works 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 in 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 is achieved. In other words, the coil module provided in the present application achieves the thinning of the coil by optimizing the design of the coil, and takes into account the effects of high-power and high-degree-of-freedom wireless charging.

[0107] It should be noted that the coil module provided in this application is not only suitable for wireless charging scenarios, but also for other scenarios that utilize the principle of electromagnetic induction.

[0108] The structure of the coil module provided in the embodiment of the present application is described below.

[0109] See also Figure 4 , Figure 4 This is a film layer structure diagram of a coil module provided in an embodiment of the present application. Figure 4 As shown, the coil module 30 includes a coil structure 31 and a magnetic conductive layer 32 located on one side of the coil structure 31, and the coil structure 31 and the magnetic conductive layer 32 are fixed together by a double-sided adhesive layer (such as double-sided tape) 33. The setting 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 foregoing that the coil module 30 is arranged in a wireless charging receiving device, and the wireless charging receiving device can include structures such as a PCB board, a PCB bracket, a battery, and a middle frame. The structures such as a PCB board, a PCB bracket, a battery, and a middle frame are generally metal, and the magnetic field will generate eddy current losses on the PCB board, the PCB bracket, the battery, the middle frame, etc. The setting 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, the PCB bracket, the battery, the middle frame, etc.

[0110] 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, and the soft magnetic material includes ferrite or nanocrystal. Figure 4 The soft magnetic material includes nanocrystals as an example. When the soft magnetic material includes nanocrystals, the magnetic conductive sublayer 322 includes multiple layers of nanocrystals 3221 and multiple layers of adhesive 3222 for bonding two adjacent layers of nanocrystals 3221 together, wherein: Figure 4 The description is made by taking the example that the magnetic conductive sublayer 322 includes four layers of nanocrystals 3221 and five layers of adhesive 3222. Accordingly, the insulating sublayer 321 can be a nanocrystal black film.

[0111] The thickness H21 of the nanocrystalline black film can be 5 μm, the thickness H22 of the nanocrystalline 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 nanocrystalline 3221, and / or the thickness of the adhesive 3222 can also be adaptively changed to meet different requirements.

[0112] The coil structure 31 can be an FPC coil; of course, the coil structure 31 is not limited to the FPC coil, and the coil structure 31 can also adopt an enameled wire coil with multiple strands wound together, etc. Among them, Figure 4 An example is given with the coil structure 31 being an FPC coil. Continue to refer to Figure 4 , the coil structure 31 includes two protective films 311 and a functional layer 312 located between the two protective films 311. The protective film 311 includes a polyimide (PI) layer 3111 and an adhesive 3112 for disposing the PI layer 3111 on the functional layer 312. The functional layer 312 includes at least two wiring sub-layers 3121 and an insulator layer 3122 located between adjacent two wiring sub-layers 3121. Figure 4 An example is given with the functional layer 312 including two wiring sub-layers 3121.

[0113] The wiring sub-layer 3121 can be a whole-surface metal layer. Among them, the material of the metal layer includes copper, aluminum, nickel, or alloy, etc. Then, a coil is formed by etching the metal layer. The specific circuit design of the formed coil will be introduced in detail in the following content and will not be elaborated here.

[0114] In order to realize the electrical connection between the two wiring sub-layers 3121, vias are formed in the insulator layer 3122 located between the two wiring sub-layers 3121, and a connection structure (not shown in the figure) for connecting the two wiring sub-layers 3121 is disposed in the vias. The embodiment of the present application does not limit the formation method of the connection structure. For example, continue to refer to Figure 4 , a whole-layer 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 vias to form a connection structure. Another example is to directly form a connection structure in the vias of the insulator layer 3122 (not shown in the figure).

[0115] The thickness H1 of the above coil structure 31 can be greater than or equal to 0.07 mm and less than or equal to 0.175 mm.

[0116] Exemplarily, the thickness H1 of the coil structure 31 can be 103.5 μm. Among them, 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 insulator layer 3122 can be 12.5 μm, the thickness H14 of the wiring sub-layer 3121 can be 15 μm, and the thickness H15 of the connection layer 3123 can be 18 μm.

[0117] In addition, the double-sided adhesive 33 between the coil structure 31 and the magnetic conductive layer 32 can be 10 μm. 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.

[0118] In order to further reduce the thickness of the coil module 30, refer to Figure 5 , Figure 5 , which is another film layer structure diagram of the coil module provided by the embodiment of the present application. As Figure 5 shown, the insulator layer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 is provided with a hollowed-out portion 3211. This hollowed-out portion 3211 can expose the adhesive 3222 between the insulator layer 321 and the nanocrystalline 3221. The double-sided adhesive 33 bonding the coil structure 31 and the magnetic conductive layer 32 is located in this hollowed-out portion 3211 and contacts the adhesive 3222 between the insulator layer 321 and the nanocrystalline 3221. That is to say, the area of the insulator layer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 and overlaps with the coil structure 31 is partially removed, so that the double-sided adhesive 33 bonding the coil structure 31 and the magnetic conductive layer 32 directly bonds with the adhesive 3222 on the nanocrystalline 3221.

[0119] It can be understood that in order to ensure the bonding strength between the coil structure 31 and the magnetic conductive layer 32, the thickness of the double-sided adhesive 33 still needs to be maintained at 10 μm. Therefore, the thickness of the insulator layer 321 in the magnetic conductive layer 32 that contacts the coil structure 31 and the film layer where the double-sided adhesive 33 is located is 10 μm. In this way, the thickness of the coil module 30 can be reduced by 5 μm (the thickness of one insulator layer 321), that is, the thickness of the coil module 30 is 201.5 μm, and the thickness of the coil module 30 is relatively small.

[0120] As can be seen from the foregoing content, 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 relatively small, 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.

[0121] The film layer structure of the coil module has been introduced above. 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 relatively thin, the impedance of the coil module is generally large, and the large impedance is not conducive to high-power charging of the wireless charging receiving device. In order to achieve the effects of high-power charging and thin and light of the wireless charging receiving device at the same time, refer to Figure 6a and Figure 6b , Figure 6a is a front view structure schematic diagram of a coil structure provided by an embodiment of the present application, Figure 6b is a front view structure schematic diagram of another coil structure provided by an embodiment of the present application. As Figure 6a and Figure 6b shown, the coil structure 31 of the embodiment of the present application can be a toroidal coil. Among them, 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 outer diameter d1 of the coil is 46 mm, 47 mm, 48 mm, 49 mm, 50 mm, 51 mm or 52 mm; the inner diameter d2 of the coil 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.

[0122] It should be noted that the specific form of the toroidal coil in the embodiment of the present application is not limited, and those skilled in the art can set it according to the actual situation. Exemplarily, the toroidal coil includes a circular toroidal coil, a rectangular toroidal coil, a hexagonal toroidal coil, an octagonal toroidal coil, etc. The embodiment of the present application takes the toroidal coil as a circular toroidal coil as an example for illustration.

[0123] In addition, the inductance L of the coil structure 31 provided by 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 works in a magnetic coupling or magnetic resonance wireless power transmission system with different frequencies, the inductance of the coil structure 31 is different. Exemplarily, when the coil module works in a magnetic coupling or magnetic resonance wireless power transmission system with 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.

[0124] Continue to refer to Figure 6a and Figure 6b, the coil structure 31 includes a first end D1, a second end D2, and N sets of coil groups 31a connected in series in sequence. The first end D1 and the second end D2 are connected through N sets of coil groups 31a connected in series in sequence. Among them, one set of coil group 31a is one turn (i.e., one loop) of the coil structure 31. N is less than or equal to 8.5 and greater than or equal to 7.5, that is, the number of turns of the coil structure 31 is 7.5 turns to 8.5 turns. 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 in the figure), etc. 0.5 turn means the wire is wound half a circle. Exemplarily, 7.5 turns can be formed by winding half a circle on the outermost coil group 31a among 7 sets of coil groups 31a, or can be formed by winding half a circle on the innermost coil group 31a among 7 sets of coil groups 31a. Among them, Figure 6b The description is given by taking the example of forming 7.5 turns by winding half a circle on the innermost coil group 31a among 7 sets of coil groups 31a. 8.5 turns can be formed by winding half a circle on the outermost coil group 31a among 8 sets of coil groups 31a, or can be formed by winding half a circle on the innermost coil group 31a among 8 sets of coil groups 31a.

[0125] Each set of coil group 31a includes M strands of wire 311a. M can be less than or equal to 5 and greater than or equal to 3. Exemplarily, M is 3, 4, or 5. Figure 6a and Figure 6b Both take M as 4 as an example for the description. That is to say, the coil structure 31 is continuously wound by M strands of wire 311a starting from the first end D1 (forming N sets of coil groups 31a connected in series in sequence) until it is connected to the second end D2, and is distributed on two two-layer wiring sub-layers 3121. The current is input from the first end D1, passes through N sets of coil groups 31a, and outputs from the second end D2.

[0126] It is set that M can be less than or equal to 5 and greater than or equal to 3 because the outer diameter d1 of the coil of the toroidal 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, that is, the area for arranging the wire 311a is limited. In the limited area, it will not cause the impedance of the wiring sub-layer 3121 to increase due to more gaps between adjacent two strands of wire 311a because the number of strands of wire 311a is large, nor will it affect the current transmission due to fewer current-carrying channels caused by the skin effect because the number of strands of wire 311a is small.

[0127] Continue to refer to Figure 6a , N sets of coil groups 31a include L sets of internal coil groups 31a ( Figure 6aThe coil group 31a within the ZZ region is the internal coil group 31a, and the ZZ region is the region enclosed by the innermost curved loop and the middle curved loop), where L is less than or equal to N. When L is less than N, the N coil groups 31a further include (N - L) external coil groups 31a arranged around the L internal coil groups 31a( Figure 6a The coil group 31a within the YY region is the external coil group 31a, and the YY region is the region enclosed by the outermost curved loop and the middle curved loop).

[0128] See Figure 7 、 Figure 8a and Figure 8b , Figure 7 is Figure 6a the sectional view of the coil shown along the AA' direction, Figure 8a is Figure 6a the front view structure diagram of the first wiring sub-layer in the coil structure shown, Figure 8b is Figure 6a the front view structure diagram of the second wiring sub-layer in the coil structure shown. As Figure 6a 、 Figure 7 、 Figure 8a and Figure 8b shown, when L is equal to N, that is, when the N coil groups 31a do not include external coil groups 31a, the L internal coil groups 31a are wound successively along the meridional direction, and the L internal coil groups 31a have double-sided wiring, that is, the L internal coil groups 31a are arranged in two wiring sub-layers 3121. For the sake of distinction, the two wiring sub-layers 3121 are respectively the first wiring sub-layer 3121a and the second wiring sub-layer 3121b, that is, the L internal coil groups 31a are distributed in the two wiring sub-layers 3121 in parallel. That is to say, both the first wiring sub-layer 3121a and the second wiring sub-layer 3121b are wound with L internal coil groups 31a, and the L internal coil groups 31a of the first wiring sub-layer 3121a and the L internal coil groups 31a of the second wiring sub-layer 3121b are respectively electrically connected.

[0129] When L is less than N, the L internal coil groups 31a are wound successively along the meridional direction, both the first wiring sub-layer 3121a and the second wiring sub-layer 3121b are wound with L internal coil groups 31a, and the L internal coil groups 31a of the first wiring sub-layer 3121a and the L internal coil groups 31a of the second wiring sub-layer 3121b are respectively electrically connected. 2 / (N - L) of the (N - L) external coil groups 31a are arranged in the first wiring sub-layer 3121a and are connected in series with the L internal coil groups 31a of the first wiring sub-layer 3121a, and the remaining 2 / (N - L) external coil groups 31a are arranged in the second wiring sub-layer 3121b and are connected in series with the L internal coil groups 31a of the second wiring sub-layer 3121b, so that the N coil groups 31a are connected in series successively.

[0130] For the convenience of understanding the above content, next, in combination with specific examples, the circuit design of the coil structure provided by the embodiments of the present application will be introduced. Among them, taking N as 8, that is, the coil structure 31 includes 8 groups of coil groups 31a connected in series in sequence (the number of turns of the coil structure 31 is 8 turns) as an example for illustration.

[0131] Example 1, L is equal to 4, M is equal to 4 or 5. Among them, in this example, M is taken as 4 for illustration. Continue to refer to Figure 7 、 Figure 8a and Figure 8b , the 8 groups of coil groups 31a include 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. The 8 groups of coil groups 31a include 4 groups of internal coil groups 31a and 4 groups of external coil groups 31a arranged around the 4 groups of internal coil groups 31a. The 4 groups of internal coil groups 31a are the third coil group 31a3, the fourth coil group 31a4, the fifth coil group 31a5, and the sixth coil group 31a6. The 4 groups of external coil groups 31a are the first coil group 31a1, the second coil group 31a2, the seventh coil group 31a7, and the eighth coil group 31a8.

[0132] 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 sequentially wound around the first wiring sub-layer 3121a in the radial direction. 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 sequentially wound around the second wiring sub-layer 3121b in the radial direction. The 4 strands of wires 311a of the third coil group 31a3 located in the first wiring sub-layer 3121a are respectively electrically connected to the 4 strands of wires 311a of the third coil group 31a3 located in the second wiring sub-layer 3121b through the connection structure in the via hole of the insulator layer 3122. The 4 strands of wires 311a of the fourth coil group 31a4 located in the first wiring sub-layer 3121a are respectively electrically connected to the 4 strands of wires 311a of the fourth coil group 31a4 located in the second wiring sub-layer 3121b through the connection structure in the via hole of the insulator layer 3122. The 4 strands of wires 311a of the fifth coil group 31a5 located in the first wiring sub-layer 3121a are respectively electrically connected to the 4 strands of wires 311a of the fifth coil group 31a5 located in the second wiring sub-layer 3121b through the connection structure in the via hole of the insulator layer 3122. The 4 strands of wires 311a of the sixth coil group 31a6 located in the first wiring sub-layer 3121a are respectively electrically connected to the 4 strands of wires 311a of the sixth coil group 31a6 located in the second wiring sub-layer 3121b through the connection structure in the via hole of the insulator layer 3122.

[0133] The seventh coil group 31a7 located in the second wiring sub-layer 3121b surrounds the outside of the third coil group 31a3. 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 correspondingly, making the seventh coil group 31a7 and the eighth coil group 31a8 in series connection.

[0134] In addition, in combination with Figure 9 , Figure 9 is Figure 8b a partial enlarged view of the BB area in. There is a break between the third coil group 31a3 and the fourth coil group 31a4 located in the second wiring sub-layer 3121b, a break between the third coil group 31a3 and the fourth coil group 31a4 located in the second wiring sub-layer 3121b, a break between the fourth coil group 31a4 and the fifth coil group 31a5 located in the second wiring sub-layer 3121b, a break between the fifth coil group 31a5 and the sixth coil group 31a6 located in the second wiring sub-layer 3121b. The four wires 311a of the sixth coil group 31a6 pass through the broken area (such as the CC area in Figure 9 ) and are respectively connected to the four wires 311a of the seventh coil group 31a7 correspondingly.

[0135] It can be understood that when the number of turns of the coil structure 31 can be 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 broken area, and pass through the broken area to be connected to the sixth coil group 31a6 located in the second wiring sub-layer 3121b. And the sixth coil group 31a6 is in series connection with the seventh coil group 31a7, and the seventh coil group 31a7 is connected to the second end D2. Similarly, when the number of turns of the coil structure 31 can be 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 broken area, and pass through the broken area to be connected to the seventh coil group 31a7 located in the second wiring sub-layer 3121b. And the seventh coil group 31a7 is in series connection with the eighth coil group 31a8, and the eighth coil group 31a8 is connected to the second end D2.

[0136] That is to say, in this example: among the 8 coil groups 31a (the number of turns of the coil structure 31 is 8 turns), 4 internal coil groups 31a (i.e., 4 turns) have double-sided wiring, and the remaining 4 external coil groups 31a (i.e., 4 turns) are evenly distributed on the first wiring sub-layer 3121a and the second wiring sub-layer 3121b, that is, there are 2 external coil groups 31a (i.e., 2 turns) on each of the first wiring sub-layer 3121a and the second wiring sub-layer 3121b.

[0137] Example 2, L equals 2, M equals 4 or 5. In this example, M is taken as 4 for illustration. Refer to Figure 10 、 Figure 11 、 Figure 12a and Figure 12b , Figure 10 which is a front view structural diagram of another coil structure provided by an embodiment of the present application, Figure 11 is Figure 10 a sectional view of the coil shown along the DD' direction, Figure 12a is Figure 10 a front view structural diagram of the first wiring sub-layer in the coil structure shown, Figure 12b is Figure 10 a front view structural diagram of the second wiring sub-layer in the coil structure shown. As shown in Figure 10 、 Figure 11 、 Figure 12a and Figure 12b shown, the 8 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 8 coil groups 31a include 2 internal coil groups 31a and 6 external coil groups 31a arranged around the 2 internal coil groups 31a. The 2 internal coil groups 31a are the fourth coil group 31a4 and the fifth coil group 31a5. The 6 external coil groups 31a are the first coil group 31a1, the second coil group 31a2, the third coil group 31a3, the sixth coil group 31a6, the seventh coil group 31a7, and the eighth coil group 31a8.

[0138] 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 wound around the first wiring sub-layer 3121a in sequence along the radial direction. 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 wound around the second wiring sub-layer 3121b in sequence along the radial direction. The 4 wires 311a of the fourth coil group 31a4 located in the first wiring sub-layer 3121a are electrically connected to the 4 wires 311a of the fourth coil group 31a4 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122, and the 4 wires 311a of the fifth coil group 31a5 located in the first wiring sub-layer 3121a are electrically connected to the 4 wires 311a of the fifth coil group 31a5 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122.

[0139] 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 correspondingly, so that the seventh coil group 31a7 and the eighth coil group 31a8 are connected 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 correspondingly, so that the sixth coil group 31a6 and the seventh coil group 31a7 are connected in series.

[0140] In addition, in combination with Figure 13 , Figure 13 is Figure 12b a partial enlarged view of the EE area in Figure 13 . The fourth coil group 31a4 and the fifth coil group 31a5 in the second wiring sub-layer 3121b are disconnected. The four wires 311a of the fifth coil group 31a5 pass through the disconnected area (such as the FF area in

[0141] ) and are respectively connected to the four wires 311a of the sixth coil group 31a6 correspondingly.

[0142] Example 3, L is equal to 6, and M is equal to 3, 4, or 5. Refer to Figure 14 , Figure 15 , Figure 16a and Figure 16b , Figure 14 which is a front view structural diagram of another coil structure provided by the embodiment of the present application, Figure 15 is Figure 14 a sectional view of the coil shown in the direction of GG', Figure 16a is Figure 14 a front view structural diagram of the first wiring sub-layer in the coil structure shown, Figure 16b is Figure 14 a front view structural diagram of the second wiring sub-layer in the coil structure shown, where Figure 14 , Figure 15 , Figure 16a and Figure 16b do not show the number of wire strands of each coil group. As shown in Figure 14, Figure 15 , Figure 16a and Figure 16b As shown in and

[0143] , 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 31a include six internal coil groups 31a and two external coil groups 31a disposed around the six internal coil groups 31a. The six internal coil groups 31a are 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. The two external coil groups 31a are the first coil group 31a1 and the eighth coil group 31a8.

[0143] 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 wound around the first wiring sub-layer 3121a in sequence along the radial direction. 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 wound around the second wiring sub-layer 3121b in sequence along the radial direction. The M wires 311a of the second coil group 31a2 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the second coil group 31a2 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the third coil group 31a3 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the third coil group 31a3 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the fourth coil group 31a4 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the fourth coil group 31a4 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the fifth coil group 31a5 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the fifth coil group 31a5 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the sixth coil group 31a6 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the sixth coil group 31a6 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the seventh coil group 31a7 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the seventh coil group 31a7 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122.

[0144] The eighth coil group 31a8 located in the second wiring sub-layer 3121b surrounds the outside of the second coil group 31a2, and the eighth coil group 31a8 is connected to the second end D2.

[0145] In addition, continue to refer to Figure 16b, between the second coil group 31a2 and the third coil group 31a3 located in the second wiring sub-layer 3121b is disconnected, between the third coil group 31a3 and the fourth coil group 31a4 located in the second wiring sub-layer 3121b is disconnected, between the fourth coil group 31a4 and the fifth coil group 31a5 located in the second wiring sub-layer 3121b is disconnected, between the fifth coil group 31a5 and the sixth coil group 31a6 located in the second wiring sub-layer 3121b is disconnected, between the sixth coil group 31a6 and the seventh coil group 31a7 located in the second wiring sub-layer 3121b is disconnected, and the M strands of wire 311a of the seventh coil group 31a7 pass through the disconnected area (such as Figure 16b 's HH area) and are respectively connected to the M strands of wire 311a of the eighth coil group 31a8.

[0146] That is to say, in this example: among the 8 coil groups 31a (the number of turns of the coil structure 31 is 8 turns), 6 internal coil groups 31a (i.e., 6 turns) are double-sided wired, and the remaining 2 external coil groups 31a (i.e., 2 turns) are evenly distributed on the first wiring sub-layer 3121a and the second wiring sub-layer 3121b, that is, each of the first wiring sub-layer 3121a and the second wiring sub-layer 3121b has 1 external coil group 31a (i.e., 1 turn each).

[0147] Example 4, L is equal to 8, and M is equal to 3 or 4. See Figure 17 、 Figure 18 、 Figure 19a and Figure 19b , Figure 17 is a front view structure diagram of another coil structure provided by the embodiment of the present application, Figure 18 is Figure 17 a sectional view of the coil shown along the II' direction, Figure 19a is Figure 17 a front view structure diagram of the first wiring sub-layer in the coil structure shown, Figure 19b is Figure 17 a front view structure diagram of the second wiring sub-layer in the coil structure shown, where Figure 17 、 Figure 18 、 Figure 19a and Figure 19b do not show the number of strands of wire in each coil group. As Figure 17 、 Figure 18 、 Figure 19a and Figure 19b shown, the 8 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. All 8 coil groups 31 are internal coil groups 31a.

[0148] 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 sequentially wound around the first wiring sub-layer 3121a in the radial direction. 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 sequentially wound around the second wiring sub-layer 3121b in the radial direction. The M wires 311a of the first coil group 31a1 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the first coil group 31a1 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the second coil group 31a2 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the second coil group 31a2 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the third coil group 31a3 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the third coil group 31a3 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the fourth coil group 31a4 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the fourth coil group 31a4 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the fifth coil group 31a5 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the fifth coil group 31a5 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the sixth coil group 31a6 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the sixth coil group 31a6 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the seventh coil group 31a7 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the seventh coil group 31a7 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122. The M wires 311a of the eighth coil group 31a8 located in the first wiring sub-layer 3121a are electrically connected to the M wires 311a of the eighth coil group 31a8 located in the second wiring sub-layer 3121b respectively through the connection structure in the via hole of the insulator layer 3122.

[0149] In addition, continue to refer to Figure 19b, there are breaks between the first coil group 31a1 and the second coil group 31a2 located in the second wiring sub-layer 3121b, between the second coil group 31a2 and the third coil group 31a3 located in the second wiring sub-layer 3121b, between the third coil group 31a3 and the fourth coil group 31a4 located in the second wiring sub-layer 3121b, between the fourth coil group 31a4 and the fifth coil group 31a5 located in the second wiring sub-layer 3121b, between the fifth coil group 31a5 and the sixth coil group 31a6 located in the second wiring sub-layer 3121b, between the sixth coil group 31a6 and the seventh coil group 31a7 located in the second wiring sub-layer 3121b, between the seventh coil group 31a7 and the eighth coil group 31a8 located in the second wiring sub-layer 3121b, and M strands of wire 311a of the eighth coil group 31a8 pass through the disconnected area (such as Figure 19b the JJ area of

[0150] to be connected to the second end D2.

[0151] That is to say, in this example: among the 8 coil groups 31a (the number of turns of the coil structure 31 is 8 turns), the 8 internal coil groups 31a (i.e., 2 turns) have double-sided wiring.

[0152] In addition, the smaller the number of turns of the coil, the smaller the impedance of the coil, and the less heat will be generated in the coil. Also, since an alternating magnetic field is generated during wireless charging, this alternating magnetic field will generate eddy current losses on the metal structures (such as the PCB board, PCB bracket, battery, middle frame, etc.) in the wireless charging receiving device, and thus generate heat. When the number of turns of the coil increases, the eddy current losses generated by the magnetic field on the PCB board, PCB bracket, battery, middle frame, etc. generally decrease, and the heat on the metal structure decreases. Therefore, in this application, by setting the outer diameter d1 of the coil of the coil structure 31 to be less than or equal to 52 mm and greater than or equal to 46 mm, such as 50 mm; the inner diameter d2 of the coil to be less than or equal to 28 mm and less than or equal to 16 mm, and the number of turns of the coil structure 31 to be 8 turns, in the case of thinning the coil, the sum of the losses of the coil 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 the effects of high-power and high-degree-of-freedom wireless charging.

[0153] It should be noted that in the embodiments of this application, the number of turns of the coil structure 31 is taken as 8 turns for illustration. When the number of turns of the coil structure 31 is 7.5 turns or 8.5 turns, similar effects are achieved, which will not be elaborated here one by one.

[0154] To better illustrate this effect, a simulation test was conducted on the coil structure provided in the embodiments of this application. The simulation test results are shown in Table 1. Among them, the values corresponding to the number of turns of the coil, the current on the transmitting side (Itx), the frequency (freq), and the load are operating parameters, and the values corresponding to the middle frame, main board,..., TX aluminum plate, etc. are loss values.

[0155] Table 1 Comparison of losses with different numbers of turns

[0156]

[0157]

[0158] As can be seen from Table 1, when the number of turns of the coil structure 31 is 8 turns, although the impedance of the coil structure 31 is relatively large, the sum of the eddy current losses generated by the magnetic field on the PCB board, PCB bracket, battery, metal (such as nanocrystals) inside the coil structure 31, coil, middle frame, etc. is relatively small. Therefore, the overall loss of the wireless charging receiving device is minimized. It can be concluded that by setting the outer diameter d1 of the coil of the coil structure 31 to be less than or equal to 52 mm and greater than or equal to 46 mm, such as 50 mm; the inner diameter d2 of the coil to be less than or equal to 28 mm and less than or equal to 16 mm, and the number of turns of the coil structure 31 to be 8 turns, in the case of thinning the coil (the thickness can be less than or equal to 0.2 mm), the coil structure 30 can achieve the effect of high power.

[0159] As is known to those skilled in the art, the higher the mutual inductance between the receiving coil and the transmitting coil, the higher the charging efficiency. Refer to Figure 20 , Figure 20 which 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 in the embodiment of the present application is different. Figure 20 In , the abscissa is the offset distance between the receiving coil and the transmitting coil, with the unit of mm, and the ordinate is the mutual inductance value, with the unit of 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 Figure 20 shown, for the coil structure 31 with 7 turns: when the receiving coil and the transmitting coil are facing each other, the mutual inductance value is about 5 μH; 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. For the coil structure 31 with 8 turns: when the receiving coil and the transmitting coil are facing each other, the mutual inductance value is about 7 μH, which is greater than the mutual inductance value when the number of turns of the coil structure 31 is 7 turns and when the receiving coil and the transmitting coil are facing each other; 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, but when the offset distance between the receiving coil and the transmitting coil is the same, the mutual inductance value when the number of turns of the coil structure 31 is 8 turns is greater than the mutual inductance value when the number of turns of the coil structure 31 is 7 turns. That is to say, when the number of turns of the coil structure 31 is 8 turns, even if the receiving coil and the transmitting coil are offset, there is still a relatively high mutual inductance value between the receiving coil and the transmitting coil. From this, it can be concluded that the coil structure 30 also takes into account the effect of high-degree-of-freedom wireless charging.

[0160] In some embodiments, the width d3 of each wire 311a in the L-group internal coil group 31a is less than or equal to 0.6 mm and greater than or equal to 0.3 mm.

[0161] This is because the magnetic field intensity inside the coil structure 31 is relatively strong, and the current density distribution is uneven. Too wide a wire trace will increase the eddy current loss; too thin a wire trace, since the wire in the FPC coil used in the present application is relatively thin, the eddy current loss has already been reduced to some extent, and a wire trace with a width below 0.3 mm is meaningless. Therefore, when the width d3 of each wire in the L-group internal coil group 31a is less than or equal to 0.6 mm and greater than or equal to 0.3 mm, the eddy current loss is relatively low, further improving the charging effect.

[0162] In some embodiments, the arrangement order of the M wires 311a of at least one set of coils 10 in the L-group internal coil set 31a is changed along the radial direction of the coil structure 31, so that the wires 311a close to the center of the coil structure 31 in one set of internal coil sets 31a move outward (in the direction away from the center of the coil structure 31), and the wires 311a far from the center of the coil structure 31 move inward. In one set of internal coil sets 31a, the current density of the wires 311a located on both sides along the radial direction is large, and the current density of the wires 311a in the middle is small. By changing the radial positions of the M wires 311a, the current density of the M wires 311a is changed, and the uniformity of the current distribution of the multiple wires 311a in the coil set 31a is improved.

[0163] The M wires 311a in one internal coil set 31a are evenly distributed on two wiring sub-layers 3121, and the arrangement order of the M wires 311a along the radial direction is opposite by means of crossing.

[0164] See Figure 21 , Figure 21 which is a schematic diagram of a crossing structure of different wires in the same coil set provided by the embodiments of the present application. Figure 22 is Figure 21 the schematic diagram of the crossing structure shown. Figure 23 is Figure 22 the sectional view along the OO' direction. As shown in Figures 21 - 23 , in one internal coil set 31a, the number of wires 311a is 3. The three wires 311a are divided into a first wire 311a1, a second wire 311a2, and a third wire 311a3. Since the 3 wires 311a in one internal coil set 31a are evenly distributed on two wiring sub-layers 3121, the first wiring sub-layer 3121a and the second wiring sub-layer 3121b are both provided with the first wire 311a1, the second wire 311a2, and the third wire 311a3, and are respectively electrically connected. For distinction, the first wire 311a1 of the first wiring sub-layer 3121a is abbreviated as 311a1-1, the second wire 311a2 of the first wiring sub-layer 3121a is abbreviated as the second wire 311a2-1, and the third wire 311a3 of the first wiring sub-layer 3121a is abbreviated as the third wire 311a3-1; the first wire 311a1 of the second wiring sub-layer 3121b is abbreviated as 311a1-2, the second wire 311a2 of the second wiring sub-layer 3121b is abbreviated as the second wire 311a2-2, and the third wire 311a3 of the second wiring sub-layer 3121b is abbreviated as the third wire 311a3-2.

[0165] Radially, the first wire 311a1 and the third wire 311a3 are located on both sides of the second wire 311a2. The coil structure 31 includes a preset crossing area, and those skilled in the art can select the specific position of the preset crossing area according to the actual situation. The first wire 311a1-1 of the first wiring sub-layer 3121a and the third wire 311a3-2 of the second wiring sub-layer 3121b cross in the preset crossing area, and the first wire 311a1-2 of the second wiring sub-layer 3121b is disconnected at the preset crossing area, and the third wire 311a3-1 of the first wiring sub-layer 3121b is disconnected at the preset crossing area. The second wire 311a2-1 of the first wiring sub-layer 3121a and the second wire 311a2-2 of the second wiring sub-layer 3121b are disconnected at the preset crossing area, and the disconnected part of the second wire 311a2-1 of the first wiring sub-layer 3121a overlaps with the disconnected part of the second wire 311a2-2 of the second wiring sub-layer 3121b on the reference plane. The disconnected part of the second wire 311a2-1 of the first wiring sub-layer 3121a and the disconnected part of the second wire 311a2-2 of the second wiring sub-layer 3121b are electrically connected through the connection structure 31221 in the via of the insulator layer 3122, where the reference plane is a plane parallel to the plane where the magnetic conductive layer 32 is located.

[0166] See Figure 24 , Figure 25 , Figure 26 , Figure 27 and Figure 28 , Figure 24 is another schematic diagram of the crossing structure of different strands of wires in the same coil group provided by the embodiment of the present application. Figure 25 is Figure 8a the enlarged view of the KK area in Figure 26 is Figure 8b the enlarged view of the MM area in Figure 27 is Figure 8a the enlarged view of the LL area in Figure 28 is Figure 8b the enlarged view of the NN area in. As Figure 24 , Figure 25 , Figure 26 , Figure 27 and Figure 28As shown, in an internal coil group 31a, the number of strands of the wire 311a is 4. The four strands of the wire 311a are divided into a first wire 311a1, a second wire 311a2, a third wire 311a3, and a fourth wire 311a4. Since the 4 strands of the wire 311a in an internal coil group 31a are evenly distributed on two wiring sub-layers 3121, therefore, both the first wiring sub-layer 3121a and the second wiring sub-layer 3121b are provided with the first wire 311a1, the second wire 311a2, the third wire 311a3, and the fourth wire 311a4, and are electrically connected respectively. For the sake of distinction, the first wire 311a1 of the first wiring sub-layer 3121a is abbreviated as 311a1-1, the second wire 311a2 of the first wiring sub-layer 3121a is abbreviated as the second wire 311a2-1, the third wire 311a3 of the first wiring sub-layer 3121a is abbreviated as the third wire 311a3-1, and the fourth wire 311a4 of the first wiring sub-layer 3121a is abbreviated as the third wire 311a4-1; the first wire 311a1 of the second wiring sub-layer 3121b is abbreviated as 311a1-2, the second wire 311a2 of the second wiring sub-layer 3121b is abbreviated as the second wire 311a2-2, the third wire 311a3 of the second wiring sub-layer 3121b is abbreviated as the third wire 311a3-2, and the fourth wire 311a4 of the second wiring sub-layer 3121b is abbreviated as the fourth wire 311a4-2.

[0167] The coil structure 31 includes two preset crossover regions, namely a first preset crossover region and a second preset crossover region. Those skilled in the art can select the specific positions of the first preset crossover region and the second preset crossover region according to the actual situation. Continue to refer to Figure 25 and Figure 26, before the four wires 311a are wound around the first preset crossover area, in the radial direction and away from the center of the coil structure 31, the first wire 311a1, the second wire 311a2, the third wire 311a3, and the fourth wire 311a4 are arranged in sequence. When the four wires 311a are wound around the first preset crossover area, the first wire 311a1-1 of the first wiring sub-layer 3121a and the second wire 311a2-2 of the second wiring sub-layer 3121b cross in the first preset crossover area, and the first wire 311a1-2 of the second wiring sub-layer 3121b is disconnected at the first preset crossover area, and the second wire 311a2-1 of the first wiring sub-layer 3121b is disconnected at the first preset crossover area; the third wire 311a3-1 of the first wiring sub-layer 3121a and the fourth wire 311a4-2 of the second wiring sub-layer 3121b cross in the first preset crossover area, and the third wire 311a3-2 of the second wiring sub-layer 3121b is disconnected at the first preset crossover area, and the fourth wire 311a4-1 of the first wiring sub-layer 3121b is disconnected at the first preset crossover area. At this time, in the radial direction and away from the center of the coil structure 31, the arrangement of the four wires 311a changes 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. Continue to refer to Figure 27 and Figure 28 , when the four wires 311a arranged in this order (in the radial direction and away from the center of the coil structure 31, the second wire 311a2, the first wire 311a1, the fourth wire 311a4, and the third wire 311a3 are arranged in sequence) are wound around the second preset crossover area, the third wire 311a3-1, the fourth wire 311a4-1 of the first wiring sub-layer 3121a and the first wire 311a1-2, the second wire 311a2-2 of the second wiring sub-layer 3121b cross in the second preset crossover area, and the third wire 311a3-2 and the fourth wire 311a4-2 of the second wiring sub-layer 3121b are disconnected at the second preset crossover area, and the first wire 311a1 and the second wire 311a2-1 of the first wiring sub-layer 3121b are disconnected at the second preset crossover area. At this time, in 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.

[0168] Refer to Figure 29 , Figure 29This is another schematic diagram of the crossover structure of different strands of wire in the same coil group provided by the embodiments of the present application. As Figure 29 shown, in an internal coil group 31a, the number of strands of the wire 311a is 5. The five strands of wire 311a are divided into a first wire 311a1, a second wire 311a2, a third wire 311a3, a fourth wire 311a4, and a fifth wire 311a4. Since the 5 strands of wire 311a in an internal coil group 31a are evenly distributed on two wiring sub-layers 3121, therefore, the first wiring sub-layer 3121a and the second wiring sub-layer 3121b are both provided with the first wire 311a1, the second wire 311a2, the third wire 311a3, the fourth wire 311a4, and the fifth wire 311a4, and are electrically connected respectively.

[0169] The coil structure 31 includes two preset crossover regions, namely a first preset crossover region and a second preset crossover region. Those skilled in the art can select the specific positions of the first preset crossover region and the second preset crossover region according to actual situations. At the first preset crossover region, the first wire 311a1 and the second wire 311a2 exchange their orders, and the fourth wire 311a4 and the fifth wire 311a4 exchange their arrangement orders. The arrangement order of the remaining third wire 311a3 remains unchanged. At this time, along the radial direction and away from the center of the coil structure 31, the arrangement of the five strands of wire 311a changes from the first wire 311a1, the second wire 311a2, the third wire 311a3, the fourth wire 311a4, and the fifth wire 311a5 arranged in sequence to the second wire 311a2, the first wire 311a1, the third wire 311a3, the fifth wire 311a5, and the fourth wire 311a4 arranged in sequence. At the second preset crossover region, the crossover group composed of the first wire 311a1 and the second wire 311a2 and the crossover group composed of the fourth wire 311a4 and the fifth wire 311a4 exchange their arrangement orders. The arrangement order of the remaining third wire 311a3 remains unchanged. At this time, along the radial direction and away from the center of the coil structure 31, the arrangement of the five strands of wire 311a changes from the second wire 311a2, the first wire 311a1, the third wire 311a3, the fifth wire 311a5, and the fourth wire 311a4 arranged in sequence to the fifth wire 311a5, the fourth wire 311a4, the third wire 311a3, the second wire 311a2, and the first wire 311a1 arranged in sequence. The specific crossover principle is similar to the above content. For details, reference can be made to the above content and will not be elaborated here.

[0170] In summary, when the thickness of the coil module provided by the present application is less than or equal to 0.2 mm, by reasonably setting the coil module, such as selecting appropriate coil turns, coil strands, coil diameter, and wire sorting, etc., the effects of high-power and high-degree-of-freedom wireless charging can be taken into account.

[0171] The beneficial effects will be described in detail below by way of comparative examples.

[0172] Table 2 Comparison of 50W High-Power Charging

[0173]

[0174]

[0175] The losses of each structure of the wireless charging system using the coil structure of the present application (with a thickness of 0.2 mm and using the number of coil turns, number of coil strands, coil diameter, wire sorting, etc. in the embodiments of the present application) and the wire charging system using the coil structure of the prior art (with a thickness of 0.3 mm for example) were respectively subjected to simulation tests, and the simulation test results are shown in Table 2.

[0176] 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 0.2 mm thick and the coil impedance is 230 mΩ, which is larger than the impedance of the 0.3 mm coil in the comparative scheme (the impedance is 110 mΩ), and the coil structure of the present application generates more heat (up to 2.1 W for example). 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 appropriate number of coil turns, number of coil strands, coil diameter, wire sorting, etc. Among them, the eddy current loss of the present application is only 856.14 mW, which is 746.32 mW lower than that of the comparative scheme, and the advantage is obvious. 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 50W load, it is 3.7A for the present application and 4A for the comparative scheme). Therefore, it can bring lower transmission loss, lower transmission heat generation, and reduce the current pressure on the transmitting side. The transmitting side has a higher margin to support wireless charging after misalignment, thus bringing greater charging freedom. In addition, from the values corresponding to the heat generation summary of the mobile phone (wireless charging receiving device) and the heat generation summary of the transmitting side in Table 2, it can be seen that the loss of the mobile phone end of the present application is 158.94 mW lower than that of the comparative scheme; the loss of the transmitting side of the present application is 1032.69 mW lower than that of the comparative scheme. In summary, the coil structure scheme provided by the present application has a charging efficiency 1.34% higher than that of the comparative scheme (83.80% for the present application and 82.46% for the comparative scheme).

[0177] Therefore, through simulation tests, it can be known that the coil structure provided by the embodiments of the present application takes into account the effects of thin and light, high power, and high-degree-of-freedom wireless charging at the same time.

[0178] Those skilled in the art can understand that in actual settings, the above various values are variable. In this case, those skilled in the art can foresee that the coil structure scheme in the embodiments of the present application is superior to the coil structure scheme in the prior art.

[0179] 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 foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions 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 an annular 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 provided on the insulator layer, and connection structures are provided 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, wherein 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 sequentially 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 electrically connected correspondingly.

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. 2 / (N - L) 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 2 / (N - L) 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 in sequence.

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 the first wire, the second wire, and the third wire respectively; 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 crossover 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 crossover area, and the first wire of the second wiring sub-layer is disconnected at the preset crossover area, and the third wire of the first wiring sub-layer is disconnected at the preset crossover 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 crossover 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 via hole of the insulator layer. Here, the reference plane is a plane perpendicular to the thickness direction of the coil structure.

11. The coil module according to claim 9, wherein 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 crossover area and a second preset crossover area; before the four wires are wound to the first preset crossover 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 crossover 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 crossover area, and the first wire of the second wiring sub-layer is disconnected at the first preset crossover area, and the second wire of the first wiring sub-layer is disconnected at the first preset crossover 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 crossover area, and the third wire of the second wiring sub-layer is disconnected at the first preset crossover area, and the fourth wire of the first wiring sub-layer is disconnected at the first preset crossover area; When the four wires are wound to the second preset crossover 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 crossover area, and the third wire and the fourth wire of the second wiring sub-layer are disconnected at the second preset crossover area, and the first wire and the second wire of the first wiring sub-layer are disconnected at the second preset crossover 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 crossover area and a second preset crossover area; At the first preset crossover 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 conduction sub-layer located between the two insulator layers; The insulator layer in the magnetic conductive layer that contacts the coil structure is provided with a hollowed-out portion, the hollowed-out portion exposes the magnetic conduction sub-layer, and the double-sided adhesive layer is located in the hollowed-out portion and contacts the magnetic conduction 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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