Wireless charging coil winding

Abstract

The utility model discloses a wireless charging coil winding which comprises two or more layers of wireless charging coils, the two or more layers of wireless charging coils are stacked in the vertical direction, each wireless charging coil is composed of a plurality of turns of coils formed by winding wires from inside to outside in the horizontal direction, the width of each turn of coil is the same, and the width of each turn of coil is larger than that of each turn of coil. The wire comprises a plurality of sub-wires wrapped by insulating layers, the plurality of sub-wires are wound in parallel, and for a single-turn coil, the widths of the plurality of sub-wires are gradually reduced from inside to outside. The single-turn coil is designed to be formed by winding the multiple sub-wires in parallel, and the widths of the multiple sub-wires are gradually reduced from inside to outside, so that the resistance is effectively reduced while the coil loss is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of wireless charging, in particular to a wireless charging coil winding. Background Art

[0002] Traditional wireless charging coils are usually wound with a single strand of wire, and the coil winding resistance is relatively large. In order to reduce the resistance and loss of the wireless charging coil winding, an improved technology is to use two or more strands of smaller width wires to wind in parallel to form a multi-turn coil winding. In this way, the current can pass through the gaps between the multiple strands of wire, effectively increasing the cross-sectional area of ​​the current flowing through the wire and reducing the resistance and circulation loss.

[0003] However, when the coil windings of two or more smaller-width wires are used, new problems arise. When the current I passes through the wireless charging coil, unlike the single-wire coil winding, the direction of the current I flowing through each wire in the multi-wire winding is the same. When the wireless charging coil is placed in a magnetic field, due to electromagnetic induction, induced currents IE with different directions will be generated on both sides of the multi-wire winding, thereby generating a proximity effect. The superposition of the skin effect in the coil winding will generate a large circulating current loss in the coil, and the current flowing through the copper foil will be overloaded or too low, thereby reducing the utilization rate of the copper foil in the coil and wasting the service life of the coil and copper foil.

[0004] The existing FPC multi-strand wire coils have consistent wire diameters for each coil, which reduces the circulation loss caused by skin effect and proximity effect, effectively improves the utilization rate of copper foil in the coil, and allows the current to flow through the coil more evenly and stably, avoiding current overload or low current at different positions on the wire, reducing coil circulation loss and improving the efficiency of wireless charging.

[0005] From the resistance formula, we know that: R = ρ * L / S, that is, resistance R = conductor impedance ρ * conductor length L / conductor cross-sectional area S. Impedance ρ is approximately a fixed constant, but there will be slight changes at different temperatures. Generally, the operating environment of our components is around 20°C, so we take the conductor impedance ρ20 at 20°C. Since the conductor of the FFC cable is electrolytic copper, the copper content is 99.99%, which is approximately pure copper. The impedance of pure copper at 20°C is ρ20 = 0.017241Ωmm 2 / m. Back to the original resistance formula: R = ρ20*L / S, the impedance ratio ρ20 is a constant, then the size of the resistance R depends only on the length L and cross-sectional area S of the conductor.

[0006] However, the above scheme still has shortcomings: the magnetic induction intensity of the inner circle of the coil is relatively large, and only the number of wire strands in the coil is increased without adjusting the wire diameter. From the above resistance formula, it can be seen that the above FPC multi-strand wire coil design has the problem of large resistance. Utility Model Content

[0007] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a wireless charging coil winding with low resistance.

[0008] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0009] A wireless charging coil winding comprises two or more layers of wireless charging coils, wherein the two or more layers of wireless charging coils are stacked in a vertical direction, wherein the wireless charging coil is composed of a plurality of turns of coils formed by winding a wire from the inside to the outside in a horizontal direction, wherein each turn of the coil has the same width, wherein the wire comprises a plurality of sub-wires wrapped with an insulating layer, wherein the plurality of sub-wires are wound in parallel, and for a single-turn coil, the width of the plurality of sub-wires gradually decreases from the inside to the outside.

[0010] Optionally, for a single-turn coil, the line widths of the multiple sub-conductors decrease uniformly from the inside to the outside.

[0011] Optionally, for a single-turn coil, the variation between two adjacent sub-conductors is an integer multiple of 0.01 mm.

[0012] Optionally, there is a gap between two adjacent sub-conductors.

[0013] Optionally, multiple sub-conductors are combined at the end of the innermost circle to form an inner port, and multiple sub-conductors are combined at the end of the outermost circle to form an outer port.

[0014] Optionally, the inner ports of the wireless charging coils are connected to each other, and the outer ports of the wireless charging coils are connected to each other.

[0015] The beneficial effect of the utility model is that the single-turn coil is designed to be wound by multiple sub-conductors in parallel, and the line width of the multiple sub-conductors gradually decreases from the inside to the outside, thereby effectively reducing the resistance while reducing the coil loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a schematic top view of a wireless charging coil according to an embodiment of the utility model;

[0017] Figure 2 Shown is a partial cross-sectional schematic diagram of a pair of proportional wireless charging coils in the vertical direction;

[0018] Figure 3 Shown is a partial cross-sectional schematic diagram of a wireless charging coil of another comparative proportion in the vertical direction;

[0019] Figure 4 The figure shows a partial cross-sectional schematic diagram of the wireless charging coil in the vertical direction of the first embodiment of the utility model;

[0020] Figure 5 Shown is a graph showing the change of the inductance Ls of the wireless charging coil winding of the first embodiment of the present invention and different comparison ratios;

[0021] Figure 6 The figure shows the change diagram of the DC resistance Rdc of the wireless charging coil winding of the first embodiment of the present utility model and different comparison ratios;

[0022] Figure 7 Shown is a graph showing the change in AC resistance Rs of the wireless charging coil winding of the first embodiment of the present invention and different comparison ratios.

[0023] Description of labels:

[0024] 1. Coil; 2. Wire; 21. Sub-wire; 3. Inner port; 4. Outer port. DETAILED DESCRIPTION

[0025] In order to more clearly understand the technical content, achieved purposes and effects of the utility model, the utility model is described in detail below in combination with specific implementation methods and in conjunction with the accompanying drawings. It should be noted that the implementation methods of the utility model and the features in the implementation methods can be combined with each other without conflict. In the following description, many specific details are set forth in order to fully understand the utility model. The implementation methods described are only part of the implementation methods of the utility model, not all of the implementation methods. Based on the implementation methods in the utility model, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0026] Please refer to Figure 1 As shown, the technical solution provided by the utility model is:

[0027] A wireless charging coil winding comprises two or more layers of wireless charging coils, wherein the two or more layers of wireless charging coils are stacked in a vertical direction, wherein the wireless charging coil is composed of a multi-turn coil 1 formed by winding a wire 2 from the inside to the outside in a horizontal direction, wherein each turn of the coil 1 has the same width, wherein the wire 2 comprises a plurality of sub-wires 21 wrapped with an insulating layer, wherein the plurality of sub-wires 21 are wound in parallel, and for a single-turn coil 1, the line width of the plurality of sub-wires 21 gradually decreases from the inside to the outside.

[0028] From the above description, it can be seen that the wireless charging coil winding of the utility model designs a single-turn coil to be wound in parallel with multiple sub-conductors, and the multiple sub-conductors are gradually thinner from the inside to the outside. This design has little effect on inductance, but can effectively reduce resistance.

[0029] Optionally, for the single-turn coil 1 , the line widths of the plurality of sub-conductors 21 decrease uniformly from the inside to the outside.

[0030] Optionally, for a single-turn coil 1 , the variation of two adjacent sub-conductors 21 is an integer multiple of 0.01 mm.

[0031] From the above description, it can be seen that the utility model preferably adjusts the width of multiple sub-conductors to decrease uniformly from the inside to the outside. In a preferred embodiment, the change amount of two adjacent sub-conductors is an integer multiple of 0.01 mm, which is convenient for adjustment.

[0032] Optionally, there is a gap between two adjacent sub-conductors 21 .

[0033] It can be seen from the above description that in a specific implementation, for a single-turn coil, the gap between two adjacent sub-conductors can be set to be the same, and the gap between two adjacent turns of the coil can be set to be the same.

[0034] Optionally, multiple sub-conductors 21 are combined at the ends of the innermost circle to form an inner port 3 , and multiple sub-conductors 21 are combined at the ends of the outermost circle to form an outer port 4 .

[0035] Optionally, the inner ports 3 of the wireless charging coils are connected to each other, and the outer ports 4 of the wireless charging coils are connected to each other.

[0036] Please refer to Figure 1-7 , Embodiment 1 of the present utility model is:

[0037] A wireless charging coil winding includes two or more layers of wireless charging coils, which are stacked in the vertical direction. The wireless charging coil is composed of a multi-turn coil 1 formed by winding a wire 2 from the inside to the outside in the horizontal direction. The width of each turn of the coil 1 is the same. The wire 2 includes a plurality of sub-wires 21 wrapped with an insulating layer. The plurality of sub-wires 21 are wound in parallel, and there is a gap between two adjacent sub-wires 21. For a single-turn coil 1, the plurality of sub-wires 21 are distributed from the inside to the outside, and their line widths decrease uniformly. The change in the width of two adjacent sub-wires 21 is an integer multiple of 0.01 mm. The plurality of sub-wires 21 are combined at the end of the innermost circle to form an inner port 3, and the plurality of sub-wires 21 are combined at the end of the outermost circle to form an outer port 4. The inner ports 3 of each wireless charging coil are connected to each other, and the outer ports 4 of each wireless charging coil are connected to each other. Figure 1 shown.

[0038] The following example is taken as follows: the number of sub-conductors is 4. In a single-turn coil, the line widths of the four sub-conductors distributed from the inside to the outside are represented by wirth1, wirth2, wirth3 and wirth4, respectively, in mm. The number of coil turns, the inner diameter and the outer diameter of the coil are fixed, the width of each turn of the coil is kept unchanged, and the line width of each sub-conductor is adjusted. The following Table 1 shows the impact of 15 different line width design schemes on performance. In the table, the inner diameter is the inner diameter of the wireless charging coil, in mm, the outer diameter is the outer diameter of the wireless charging coil, in mm, Ls is the inductance of the wireless charging coil winding, in μH, Rdc is the DC resistance of the wireless charging coil winding, in mohm, and Rs is the AC resistance of the wireless charging coil winding, in mohm. Among them, Schemes 1-8 are comparative examples, and Schemes 9-15 are wireless charging coil windings using this embodiment. Figure 2 The figure shows a partial cross-sectional schematic diagram of the wireless charging coil of Scheme 1 in the vertical direction. Figure 3 FIG. 8 is a partial cross-sectional schematic diagram of the wireless charging coil of Scheme 8 in the vertical direction. Figure 4 The figure shows a partial cross-sectional schematic diagram of the wireless charging coil of Scheme 15 in the vertical direction, where the coil is represented from the inside to the outside from left to right, and the same filling pattern is regarded as the same turn of the coil.

[0039] plan wirth1 wirth2 wirth3 wirth4 inner diameter outer diameter LS Rdc RS 1 0.10 0.17 0.31 0.38 20.50 48.50 8.15 165.03 356.63 2 0.12 0.18 0.30 0.36 20.50 48.50 8.15 164.97 357.45 3 0.14 0.19 0.29 0.34 20.50 48.50 8.14 164.91 357.72 4 0.16 0.20 0.28 0.32 20.50 48.50 8.14 164.86 357.60 5 0.18 0.21 0.27 0.30 20.50 48.50 8.13 164.80 357.15 6 0.20 0.22 0.26 0.28 20.50 48.50 8.13 164.74 356.46 7 0.22 0.23 0.25 0.26 20.50 48.50 8.12 164.69 355.65 8 0.24 0.24 0.24 0.24 20.50 48.50 8.12 164.63 354.72 9 0.26 0.25 0.23 0.22 20.50 48.50 8.12 164.58 353.63 10 0.28 0.26 0.22 0.20 20.50 48.50 8.12 164.52 352.53 11 0.30 0.27 0.21 0.18 20.50 48.50 8.12 164.47 351.32 12 0.32 0.28 0.20 0.16 20.50 48.50 8.12 164.41 349.95 13 0.34 0.29 0.19 0.14 20.50 48.50 8.12 164.36 348.45 14 0.36 0.30 0.18 0.12 20.50 48.50 8.12 164.30 346.70 15 0.38 0.31 0.17 0.10 20.50 48.50 8.12 164.25 344.68

[0040] Table 1

[0041] like Figure 5 The figure shows the variation of the inductance Ls of the wireless charging coil winding obtained from the 15 schemes mentioned above, wherein the abscissa is the scheme number and the ordinate is the inductance Ls. Figure 6 The figure shows the variation of the DC resistance Rdc of the wireless charging coil winding obtained from the above 15 schemes, wherein the horizontal axis is the scheme number and the vertical axis is the DC resistance Rdc. Figure 7 The figure shows the change diagram of the AC resistance Rs of the wireless charging coil winding obtained from the above 15 schemes, wherein the horizontal axis is the scheme number and the vertical axis is the DC resistance Rs.

[0042] From Table 1 and Figure 5-7 It can be seen that as the width of a single conductor sub-conductor is adjusted, for a single-turn coil, the width of the sub-conductor decreases evenly from the inner to the outer sub-conductor, and as the width of the innermost sub-conductor increases, the impact on the inductance is almost negligible; but the impact on the resistance is greater, and as the width of the innermost sub-conductor increases, the DC resistance Rdc and AC Rs decrease significantly.

[0043] In summary, it is possible to reduce coil loss, ensure inductance value, and significantly reduce resistance.

[0044] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Therefore, any modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A wireless charging coil winding, comprising two or more layers of wireless charging coils, wherein the two or more layers of wireless charging coils are stacked in a vertical direction, characterized in that: The wireless charging coil is composed of a multi-turn coil formed by winding a wire from the inside to the outside in a horizontal direction, and the width of each turn of the coil is the same. The wire includes multiple sub-wires wrapped with an insulating layer, and the multiple sub-wires are wound in parallel. For a single-turn coil, the line width of the multiple sub-wires gradually decreases from the inside to the outside.

2. The wireless charging coil winding according to claim 1, characterized in that: For a single-turn coil, the width of multiple sub-conductors decreases evenly from the inside to the outside.

3. The wireless charging coil winding according to claim 1, characterized in that: For a single-turn coil, the change between two adjacent sub-conductors is an integer multiple of 0.01 mm.

4. The wireless charging coil winding according to claim 1, characterized in that: There is a gap between two adjacent sub-conductors.

5. The wireless charging coil winding according to claim 1, characterized in that: A plurality of sub-conductors are combined at the end of the innermost circle to form an inner port, and a plurality of sub-conductors are combined at the end of the outermost circle to form an outer port.

6. The wireless charging coil winding according to claim 5, characterized in that: The inner ports of the wireless charging coils are connected to each other, and the outer ports of the wireless charging coils are connected to each other.

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