Wireless charging coil, electronic device, and method of winding a wireless charging coil

Abstract

This disclosure relates to a wireless charging coil, an electronic device, and a method for winding the wireless charging coil. The wireless charging coil includes at least one coil group, wherein each coil group includes a first layer and a second layer of coil formed by winding multiple strands of wire through through holes. Each layer of the coil includes the multiple strands of wire, and the total length of each strand of wire in each layer of the coil is equal. This wireless charging coil effectively reduces AC impedance and improves charging efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of wireless charging technology, and in particular to a wireless charging coil, an electronic device, and a method for winding the wireless charging coil. Background Technology

[0002] With the continuous development of electronic devices, the functions of terminal devices are becoming increasingly rich. For example, mobile phones support wireless charging, which has brought a new dimension to people's daily lives.

[0003] Wireless charging enables electronic devices to charge wirelessly via a wireless charging coil. There are many methods for winding wireless charging coils, and different winding methods result in different performance characteristics. With the increasing popularity of wireless charging devices, obtaining a wireless charging coil with superior performance has become a major focus. Summary of the Invention

[0004] This disclosure provides a wireless charging coil, an electronic device, and a method for winding the wireless charging coil.

[0005] According to a first aspect of the present disclosure, a wireless charging coil is provided, comprising:

[0006] At least one coil group, wherein one coil group comprises a first layer of coil and a second layer of coil formed by winding multiple strands of wire through a through hole, each layer of the coil comprising the multiple strands of wire, and the total length of each strand of wire in each layer of the coil is equal.

[0007] In some embodiments, both the first layer coil and the second layer coil include multiple turns of coil wound in a spiral plane along the circumferential direction by a first wire and a second wire, respectively.

[0008] In some embodiments, both the first layer coil and the second layer coil include multiple turns of coil wound by the first strand of wire and the second strand of wire in at least one winding cycle; wherein, one winding cycle includes four adjacent turns of wire, and the circumference of the first strand of wire and the second strand of wire are equal in one winding cycle.

[0009] In some embodiments, within one winding cycle, the radius difference between two adjacent turns is equal, and both the first layer coil and the second layer coil are wound by the first strand of wire for the first and fourth turns, and the second strand of wire for the second and third turns.

[0010] In some embodiments, the first wire is wound around the first layer coil for the first turn and then through the through hole to the fourth turn of the second layer coil, and then through the through hole to the fourth turn of the first layer coil and then through the through hole to the first turn of the second layer coil.

[0011] After the second wire is wound a second and a third turn on the first layer coil, it is wound through the through hole to the second and a third turn of the second layer coil.

[0012] In some embodiments, the conductor comprises enameled wire.

[0013] In some embodiments, the wireless charging coil includes one of the coil groups.

[0014] According to a second aspect of the present disclosure, an electronic device is provided, including the wireless charging coil described in the first aspect above, and further including: a housing and a circuit board;

[0015] The circuit board is located inside the housing, and the outlet of each wire on one of the coil groups is connected to the connection terminal of the circuit board.

[0016] In some embodiments, at least one coil group or at least one layer of coil of the coil group is located within the housing.

[0017] According to a third aspect of the present disclosure, a method for winding a wireless charging coil is provided, comprising:

[0018] Multiple strands of wire are wound through through holes in different layers to form a first layer coil and a second layer coil; wherein, the total length of each strand of wire on each layer of the coil is equal;

[0019] A coil group is formed based on the first layer coil and the second layer coil;

[0020] The wireless charging coil is formed based on at least one coil group.

[0021] In some embodiments, the multi-strand wire includes a first strand and a second strand, and the step of winding the multi-strand wire through a through-hole into different layers to form a first layer coil and a second layer coil includes:

[0022] The first and second wires are wound in a spiral plane along the circumferential direction multiple times through the through hole to form the first layer coil and the second layer coil.

[0023] In some embodiments, the step of winding the first wire and the second wire in a spiral plane in different layers along the circumferential direction multiple times through the through hole to form the first layer coil and the second layer coil includes:

[0024] The first and second wires are wound in different layers along the circumferential direction for at least one cycle through the through hole to form the first layer coil and the second layer coil; wherein, one winding cycle includes four adjacent turns of wire, and the circumference of the first and second wires is equal in one winding cycle.

[0025] In some embodiments, the step of winding the first wire and the second wire through the through-hole in different layers along the circumferential direction for at least one cycle to form the first layer coil and the second layer coil includes:

[0026] Within one winding cycle, the first strand of wire is wound through the through hole to the first layer for the first turn and the fourth turn respectively to form the first layer coil;

[0027] The second wire is wound around the second layer for a second turn and a third turn respectively through the through hole to form the second layer coil, wherein the radius difference between adjacent turns is equal.

[0028] In some embodiments, the step of winding the first wire through the through-hole onto the first layer for a first turn and a fourth turn respectively, forming the first layer coil, and winding the second wire through the through-hole onto the second layer for a second turn and a third turn respectively, forming the second layer coil, includes:

[0029] After the first wire is wound around the first layer for the first turn, it is wound through the through hole to the fourth turn of the second layer, and then wound through the through hole to the fourth turn of the first layer, and then wound through the through hole to the first turn of the second layer; after the second wire is wound around the first layer for the second turn and the third turn, it is wound through the through hole to the second turn and the third turn of the second layer, thus forming the first layer coil and the second layer coil.

[0030] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0031] In the embodiments of this disclosure, each wire is wound on a different layer of coil through a through hole, and the length of each wire on each layer of coil is equal. This makes the impedance of each wire approximately equal, effectively reducing AC impedance and reducing the problem of inconsistent current due to inconsistent impedance of each wire, thereby improving charging efficiency.

[0032] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0034] Figure 1 This is a schematic diagram of a wireless charging coil shown in an embodiment of the present disclosure. Figure 1 .

[0035] Figure 2 A schematic diagram of a wireless charging coil shown in an embodiment of this disclosure. Figure 2 .

[0036] Figure 3 This is a schematic diagram of each layer of coils shown in an embodiment of this disclosure.

[0037] Figure 4 An embodiment of this disclosure includes Figure 3 Schematic diagram of a wireless charging coil with two layers of coils Figure 3 .

[0038] Figure 5 This is a schematic diagram illustrating the principle of calculating the circumference of a wire when it is wound in a circle, according to an embodiment of this disclosure.

[0039] Figure 6 This is an example diagram of the winding of the first conductor in an embodiment of this disclosure.

[0040] Figure 7 This is an example diagram of the winding of the second conductor in an embodiment of this disclosure.

[0041] Figure 8 This is an example diagram of the winding of a double-strand wire in an embodiment of this disclosure.

[0042] Figure 9 This is an example diagram of an electronic device according to an embodiment of the present disclosure.

[0043] Figure 10 This is an example diagram of a method for winding a wireless charging coil according to an embodiment of the present disclosure. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0045] Figure 1 This is a schematic diagram of a wireless charging coil shown in an embodiment of the present disclosure. Figure 1 ,like Figure 1As shown, the wireless charging coil 100 includes:

[0046] At least one coil group 101, one of the coil groups includes a first layer coil 101A and a second layer coil 101B formed by winding multiple strands of wire through a through hole, each layer of the coil includes the multiple strands of wire, and the total length of each strand of wire on each layer of the coil is equal.

[0047] The wireless charging coil 100 can be installed in electronic devices such as mobile phones, tablets, or smart wearable devices. By transmitting and receiving electromagnetic signals through the wireless charging coil 100, the electronic device is equipped with wireless charging functionality.

[0048] In this embodiment, the wireless charging coil 100 may include one or more coil groups 101. The number of coil groups 101 can be set according to the power requirements of the electronic device. The more coil groups there are, the greater the power that can be provided.

[0049] In some embodiments, the wireless charging coil 100 includes one of the coil groups 101.

[0050] A coil assembly 101 includes two layers of coils: a first layer coil 101A and a second layer coil 101B. Both layers are wound with multiple strands of wire, and the total length of each strand of wire in each layer is equal. It should be noted that, in this embodiment, the strands of wire on the first layer coil 101A are wound onto the second layer coil 101B through through-holes, meaning each strand of wire spans different layers. Furthermore, in this embodiment, the winding shape of the wires is not limited; the first and second layers of coils can be circular, elliptical, triangular, etc.

[0051] For example, such as Figure 1 As shown, both the first layer coil 101A and the second layer coil 101B include two wires. The first wire is wire 102, shown as a solid line, and the second wire is wire 103, shown as a dashed line. The first and second wires span different layers of coils, and the total length of the two wires on each layer of coil is equal. This disclosure is not limited to two wires; it can also include any three, four, or more wires.

[0052] It should be noted that, in the embodiments of this disclosure, the wireless charging coil 100 may further include a magnetic sheet formed of ferrite or the like. The magnetic sheet has multiple through holes, and the position of each through hole on the magnetic sheet can be flexibly set according to the winding method. Each strand of wire is wound through the through holes on the magnetic sheet to form a first layer coil 101A and a second layer coil 102A, and the two layers of coils are located on opposite sides of the magnetic sheet. Alternatively, in the embodiments of this disclosure, the first layer coil 101A and the second layer coil 102A may be supported by the circular cross-section of a hollow insulating cylinder, and each strand of wire is wound through the through holes of the cylinder to form the first layer coil 101A and the second layer coil 102A.

[0053] In some embodiments, the conductor comprises enameled wire.

[0054] In this embodiment, the enameled wire comprises a conductor and an insulation layer. The conductor can be copper, aluminum, or alloy wire. The bare conductor is annealed and softened, then repeatedly coated with enamel (insulation layer) and baked to form the enameled wire. The cross-section of the enameled wire can be rectangular or circular. The first coil 101A and the second coil 101B can be spiral coils wound from the enameled wire plane.

[0055] In this embodiment, the spiral coil made by winding enameled wire has opposite magnetic poles on adjacent surfaces of each turn. After being electrically connected, they form a whole, so that the magnetic field does not cancel each other out.

[0056] In addition, in the embodiments of this disclosure, the conductor can also be a conventional alloy copper wire or aluminum wire. In order to avoid the magnetic field being affected by direct connection between the conductors, the adjacent turns of conductor can also be isolated by insulating glue.

[0057] It is understood that in the embodiments of this disclosure, each wire is wound on different layers of coil through through holes, and the total length of each wire on each layer of coil is equal, so that the impedance of each wire is approximately equal, effectively reducing AC impedance and reducing the problem of inconsistent current due to inconsistent impedance of each wire, thereby improving charging efficiency.

[0058] In some embodiments, the first layer coil 101A and the second layer coil 101B each include a multi-turn coil wound in a spiral plane along the circumferential direction by the first wire 102 and the second wire 103 respectively.

[0059] In this embodiment, each layer of coil includes two wires, which are wound in a spiral plane multiple times along the circumferential direction. It should be noted that the first wire 102 and the second wire 103 are wires of uniform width. For example, for enameled wire with a circular cross-section, different wires have uniform width, so the width of any coil turn is equal.

[0060] Figure 2 A schematic diagram of a wireless charging coil shown in an embodiment of this disclosure. Figure 2 ,like Figure 2 As shown, the wireless charging coil includes a first wire 102 and a second wire 103 that are wound around the circumference. The first wire 102 is located on the outermost ring and has a larger radius, while the second wire 103 is located on the inner second and third rings and has a relatively smaller radius. Therefore, the length of the first wire 102 can be equal to the circumference of the second wire 103 distributed on the second and third rings.

[0061] For example, if the radius of the innermost loop (the third loop) is 5cm, then the circumference of the innermost loop is 10π. If the radius of the second loop is 6cm, then the circumference of the second loop is 12π. To make the lengths of the first wire 102 and the second wire 103 equal, the first wire 102 of the outermost loop can be wound in a circular direction with a radius of 11cm. In this example, the radius of each loop of the circularly wound coil does not increase or decrease at equal intervals.

[0062] Understandably, based on the circularly wound coil, it is convenient to determine the winding radius when the first wire 102 and the second wire 103 are wound in a circular shape, so that the lengths of the two wires on each layer are equal.

[0063] In some embodiments, both the first layer coil 101A and the second layer coil 101B include multiple turns of coil wound by the first strand of wire 102 and the second strand of wire 103 in at least one winding cycle; wherein, one winding cycle includes four adjacent turns of wire, and the circumference of the first strand of wire 102 and the second strand of wire 103 is equal in one winding cycle.

[0064] In this embodiment, the first wire 102 and the second wire 103 are wound in at least one winding cycle. One winding cycle includes four adjacent turns of wire, and the circumference of the first wire 102 and the second wire 103 is equal in one winding cycle. Therefore, when multiple winding cycles are performed, the lengths of the first wire 102 and the second wire 103 are also equal.

[0065] Figure 3 This is a schematic diagram of each layer of coils shown in the embodiments of this disclosure, as follows: Figure 3 As shown, both the first layer coil 101A and the second layer coil 101B include multi-turn coils with two winding cycles. Figure 4 An embodiment of this disclosure includes Figure 3 Schematic diagram of a wireless charging coil with two layers of coils Figure 3 ,like Figure 3 As shown, the first layer coil 101A and the second layer coil 101B are stacked, with the second layer coil 101B located below the first layer coil 101A.

[0066] It is understandable that winding the coil in different winding cycles makes it easier to determine the winding method cycle by cycle, so that the total length of the first and second strands of wire are equal.

[0067] In some embodiments, within one winding cycle, the radius difference between two adjacent turns is equal, and the first layer coil 101A and the second layer coil 101B are both wound by the first strand of wire 102 for the first and fourth turns, and the second strand of wire 103 for the second and third turns.

[0068] In this embodiment, the first wire 102 is wound around the first and fourth turns, and the second wire 103 is wound around the second and third turns. Since the radius difference between adjacent turns is the same, based on the above winding method, the circumference of the first wire 102 and the second wire 103 is equal in one winding cycle.

[0069] Figure 5 This is a schematic diagram illustrating the principle of calculating the circumference of a wire when it is wound in a circle, as shown in the embodiments of this disclosure. Figure 5 As shown, the circumference of the first ring from the inside out is 2πR, the circumference of the second ring is 2π(R+Δr), the circumference of the third ring is 2π(R+2Δr), and the circumference of the fourth ring is 2π(R+3Δr). Therefore, the sum of the circumferences of the first and fourth rings is equal to the sum of the circumferences of the second and third rings.

[0070] Based on the above principle, in one winding cycle, the first wire 102 is used to wind the first and fourth turns, and the second wire 103 is used to wind the second and third turns, so that the circumference of the first wire 102 and the second wire 103 is equal in one winding cycle.

[0071] Figure 6 This is an example diagram of the winding of the first conductor in an embodiment of this disclosure. Figure 7 This is an example diagram illustrating the winding of the second conductor in an embodiment of this disclosure. Figure 6 As shown, the first conductor 102 makes the first and fourth turns in each winding cycle; as Figure 7 The second conductor 103 is wound in the second and third turns in each winding cycle.

[0072] In the embodiments of this disclosure, the winding method described above makes the impedance of the first wire 102 and the second wire 103 approximately the same every four turns, so that the current on each wire can be approximately evenly distributed, the total impedance is minimized, and the charging efficiency is improved.

[0073] It should be noted that this disclosure is not limited to the method of winding two wires four times, based on Figure 3As shown in the principle, for example, this disclosure can use four wires wound eight times. For example, the first layer coil and the second layer coil are both made by: the first wire wound the first and eighth times, the second wire wound the second and seventh times, the third wire wound the third and sixth times, and the fourth wire wound the fourth and fifth times.

[0074] In some embodiments, the first wire 102 is wound around the first layer coil 101A for the first turn and then wound through the through hole to the fourth turn of the second layer coil 101B, and then wound through the through hole to the fourth turn of the first layer coil 101A and then through the through hole to the first turn of the second layer coil 101B.

[0075] After the second conductor 103 is wound a second and a third turn on the first layer coil 101A, it is wound through the through hole to the second and a third turn of the second layer coil 101B.

[0076] Figure 8 This is an example diagram of the winding of a double-strand wire according to an embodiment of this disclosure, as shown below. Figure 8 As shown, the first wire 102 is wound around the first layer coil 101A for the first turn, and then wound around the first layer coil 101A and the second layer coil 101B in the order marked 1-3 respectively. The first wire 102 is wound around the first and fourth turns on the two layers of coils respectively; the second wire 103 is wound around the second layer coil 101B for the second turn and the third turn, and then wound around the second layer coil 101B in the order marked 1-3 respectively. Figure 8 The direction shown is used to pass through the through hole to the second layer coil 101B to wind the second and third turns.

[0077] Figure 9 This is an example diagram of an electronic device according to an embodiment of the present disclosure, such as... Figure 9 As shown, the electronic device includes the aforementioned wireless charging coil, such as wireless charging coil 100, and also includes a housing 104 and a circuit board 105.

[0078] The circuit board 105 is located inside the housing 104, and the outlet of each wire on one of the coil groups is connected to the connection terminal of the circuit board 105.

[0079] In this embodiment, the electronic device also requires a circuit board 105 to function properly. The output port of the wireless charging coil 100 is connected to the connection terminal of the circuit board 105, thereby enabling the wireless charging coil 100 to be energized and to sense a magnetic field. The connection terminal of the circuit board 105 can be a metal spring, which can be connected to the output port of each individual wire.

[0080] In some embodiments, at least one coil group 101 or at least one layer of coil of the coil group is located within the housing 104.

[0081] For example, for a mobile phone back cover, a layer of coil can be embedded inside the back cover; while for laptops with relatively thick casings, an entire coil group can be embedded inside the laptop casing.

[0082] In this embodiment, at least one coil group 101 or at least one layer of a coil group is placed inside the housing 104. Thus, the wireless charging coil 100 utilizes the thickness of the housing 104 itself to accommodate the coil, thereby reducing the increase in thickness of the electronic device that would occur when placing one or more coil groups inside the housing 104. Therefore, this embedded structure effectively reduces the number or thickness of coils within the housing compared to a non-embedded placement of coils inside the housing, thereby reducing the overall thickness of the electronic device, improving portability, and enhancing the user experience.

[0083] It should be noted that in this embodiment, the circuit board 105 is located within the housing 104, including both non-embedded placement of the circuit board 105 within the housing 104 and at least a portion of the circuit board 105 embedded within the housing 104. It is understood that by utilizing the unused space within the housing 104, excluding the wireless charging coil 100, to place the circuit board 105, and particularly by embedding at least a portion of the circuit board 105 within the housing 104, the thickness of the electronic device can also be reduced.

[0084] Figure 10 This is an example diagram of a method for winding a wireless charging coil according to an embodiment of the present disclosure, as shown below. Figure 10 As shown, the method for winding a wireless charging coil includes the following steps:

[0085] S11. Multiple strands of wire are wound through through holes in different layers to form a first layer coil and a second layer coil; wherein, the total length of each strand of wire on each layer of coil is equal;

[0086] S12. A coil group is formed based on the first layer coil and the second layer coil;

[0087] S13. The wireless charging coil is formed based on at least one coil group.

[0088] In this embodiment, multiple wires are wound through through-holes in different layers to form a first-layer coil and a second-layer coil. The lengths of the wires in each layer are equal. A coil group is formed based on the first-layer and second-layer coils, and a wireless charging coil is formed based on at least one coil group. Therefore, the impedance of each wire in the wound wireless charging coil is approximately equal, effectively reducing AC impedance and minimizing current inconsistencies caused by varying impedances of the wires, thereby improving charging efficiency.

[0089] In some embodiments, the conductor includes enameled wire, and the first layer coil and the second layer coil may be a solenoid coil wound from the plane of the enameled wire.

[0090] In some embodiments, when multiple strands of wire are wound through through holes in different layers to form a first layer coil and a second layer coil, the through holes can be through holes on a magnetic sheet, and the wires are wound through multiple through holes on the magnetic sheet to form the first layer coil and the second layer coil. Furthermore, this disclosure does not limit the winding shape of the wires; the first layer coil and the second layer coil can be circular, elliptical, triangular, or other shapes.

[0091] Furthermore, in the embodiments of this disclosure, the number of coil groups is not limited. The number of coil groups can be set according to the power requirements of the electronic device. The more coil groups there are, the greater the power that can be provided.

[0092] In some embodiments, the multi-strand wire includes a first strand and a second strand, and the step of winding the multi-strand wire through a through-hole into different layers to form a first layer coil and a second layer coil includes:

[0093] The first and second wires are wound in a spiral plane along the circumferential direction multiple times through the through hole to form the first layer coil and the second layer coil.

[0094] In this embodiment, each layer of the coil includes two wires, which are wound in a spiral plane multiple times along the circumferential direction. It is understood that, based on the circularly wound coil, it is convenient to determine the winding radius of the first and second wires when they are wound in a circular shape, thus ensuring that the lengths of the two wires in each layer are equal. For example, the radius difference between two adjacent turns may be the same, or the radius difference between two adjacent turns may be different, but the lengths of the two wires in each layer are equal.

[0095] In some embodiments, the step of winding the first wire and the second wire in a spiral plane in different layers along the circumferential direction multiple times through the through hole to form the first layer coil and the second layer coil includes:

[0096] The first and second wires are wound in different layers along the circumferential direction for at least one cycle through the through hole to form the first layer coil and the second layer coil; wherein, one winding cycle includes four adjacent turns of wire, and the circumference of the first and second wires is equal in one winding cycle.

[0097] In this embodiment, the first and second conductors are wound in at least one cycle. One cycle includes four adjacent turns of conductor, and the circumference of the first and second conductors is equal in one cycle. Therefore, when multiple cycles are wound, the lengths of the first and second conductors are also equal.

[0098] It is understandable that winding the coil in different cycles makes it easier to determine the winding method cycle by cycle, so that the lengths of the first and second strands of wire are equal.

[0099] In some embodiments, the step of winding the first wire and the second wire through the through-hole in different layers along the circumferential direction for at least one cycle to form the first layer coil and the second layer coil includes:

[0100] Within one winding cycle, the first strand of wire is wound through the through hole to the first layer for the first turn and the fourth turn respectively to form the first layer coil;

[0101] The second wire is wound around the second layer for a second turn and a third turn respectively through the through hole to form the second layer coil, wherein the radius difference between adjacent turns is equal.

[0102] In this embodiment, the winding is performed with the radius difference between adjacent turns being equal, as shown above. Figure 4 and Figure 5 The winding method shown makes the impedance of the first and second wires approximately the same every four turns, so that the current on each wire can be approximately evenly distributed, the total impedance is minimized, and the charging efficiency is improved.

[0103] In some embodiments, the step of winding the first wire through the through-hole onto the first layer for a first turn and a fourth turn respectively, forming the first layer coil, and winding the second wire through the through-hole onto the second layer for a second turn and a third turn respectively, forming the second layer coil, includes:

[0104] After the first wire is wound around the first layer for the first turn, it is wound through the through hole to the fourth turn of the second layer, and then wound through the through hole to the fourth turn of the first layer, and then wound through the through hole to the first turn of the second layer; after the second wire is wound around the first layer for the second turn and the third turn, it is wound through the through hole to the second turn and the third turn of the second layer, thus forming the first layer coil and the second layer coil.

[0105] Reference Figure 8 The winding method shown can form the first layer coil and the second layer coil of this disclosure. Here, for... Figure 8 The winding method shown will not be described in detail.

[0106] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0107] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A wireless charging coil, characterized by, include: At least one coil group, wherein one coil group comprises a first layer coil and a second layer coil formed by winding multiple strands of wire through a through hole, each layer of the coil comprising the multiple strands of wire, and the total length of each strand of wire in each layer of the coil is equal; both the first layer coil and the second layer coil comprise multiple turns of coil wound in a spiral plane along the circumferential direction by the first strand and the second strand of wire in at least one winding cycle; wherein one winding cycle comprises four adjacent turns of wire, and the circumference of the first strand and the second strand of wire is equal in one winding cycle.

2. The wireless charging coil of claim 1, wherein, Within one winding cycle, the radius difference between two adjacent turns is equal, and both the first layer coil and the second layer coil are wound by the first strand of wire for the first and fourth turns, and the second strand of wire for the second and third turns.

3. The wireless charging coil of claim 2, wherein, After the first wire is wound around the first layer coil for the first turn, it is wound through the through hole to the fourth turn of the second layer coil, and then wound through the through hole to the fourth turn of the first layer coil before being wound through the through hole to the first turn of the second layer coil. After the second wire is wound a second and a third turn on the first layer coil, it is wound through the through hole to the second and a third turn of the second layer coil.

4. The wireless charging coil according to claim 1, characterized in that, The conductor includes enameled wire.

5. The wireless charging coil according to claim 1, characterized in that, The wireless charging coil includes one of the coil groups.

6. An electronic device, characterized in that, The wireless charging coil included in any one of claims 1 to 5 further includes: a housing and a circuit board; The circuit board is located inside the housing, and the outlet of each wire on one of the coil groups is connected to the connection terminal of the circuit board.

7. The electronic device according to claim 6, characterized in that, At least one coil group or at least one layer of coil of the coil group is located within the housing.

8. A method for winding a wireless charging coil, characterized in that, include: The first and second wires are wound in a spiral plane along the circumferential direction for at least one cycle through a through hole in different layers to form a first layer coil and a second layer coil; wherein, one winding cycle includes four adjacent turns of wire, and the circumference of the first and second wires is equal in one winding cycle, and the total length of each wire in each layer of the coil is equal; A coil group is formed based on the first layer coil and the second layer coil; The wireless charging coil is formed based on at least one coil group.

9. The method according to claim 8, characterized in that, The step of winding the first and second wires in a spiral plane along the circumferential direction for at least one cycle through the through hole to form a first layer coil and a second layer coil includes: Within one winding cycle, the first strand of wire is wound in a spiral plane for the first turn and the fourth turn respectively through the through hole on the first layer to form the first layer coil; The second wire is wound in a spiral plane around the second layer for a second and third turn respectively through the through hole to form the second layer coil, wherein the radius difference between adjacent turns is equal.

10. The method according to claim 9, characterized in that, Within one winding cycle, the first strand of wire is wound in a spiral plane for the first turn and the fourth turn respectively through the through hole on the first layer to form the first layer coil; The second wire is wound in a spiral plane around the second layer for a second and third turn respectively through the through hole to form the second layer coil, including: The first wire is wound in a spiral plane on the first layer for the first turn, and then wound through the through hole to the fourth turn of the second layer. After that, it is wound through the through hole to the fourth turn of the first layer and then through the through hole to the first turn of the second layer. The second wire is wound in a spiral plane on the first layer for the second and third turns, and then wound through the through hole to the second and third turns of the second layer, thus forming the first layer coil and the second layer coil.

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