A series-parallel hybrid multi-layer multi-strand wireless charging coil

Abstract

The present invention relates to a hybrid multi-layer multi-strand wireless charging coil in series and parallel connection, comprising a coil bottom plate and a charging coil, wherein the charging coil comprises an outer ring parallel coil and an inner ring series coil, wherein the outer ring parallel coil comprises a first parallel coil and a second parallel coil, wherein the outer ring parallel coil and the inner ring series coil both comprise multi-strand coils, wherein the first parallel coil and the second parallel coil are mutually connected in parallel through parallel holes and the order between strands is changed, wherein the inner ring series coil comprises a first series coil arranged on the front side of the coil bottom plate and a second series coil arranged on the back side of the coil bottom plate, wherein the first series coil is connected in series through a via hole and the order between strands is changed, and the current spiral direction of the outer ring parallel coil and the inner ring series coil is the same. Compared with the prior art, the present invention utilizes a double-layer hybrid series and parallel connection and a structure of changing the order between strands to improve the quality factor Q value, inductance, coupling coefficient and mutual inductance between coils of the coil, thereby improving the performance while ensuring that the volume of the charging coil is small.

Description

Technical Field

[0001] The invention relates to a wireless charging coil, and in particular to a series-parallel hybrid multi-layer and multi-strand wireless charging coil. Background Art

[0002] With the development of wireless communication technology and mobile terminals, wireless charging functions are increasingly integrated into mobile phones, tablet computers, smart watches and other terminals. The role of wireless charging is to replace the traditional wired charging mode and realize a more convenient mobile charging method. Wireless charging can realize the integration of compact wireless charging functions for mobile phones and pave the way for charging multiple portable devices at the same time. When charging multiple devices, there is no restriction on the position of the devices relative to the charger, so more and more wireless terminals with wireless charging functions are entering the market.

[0003] Currently, many terminal devices are developing towards being thinner and smaller, leaving relatively little space for wireless charging. In order to meet various performance requirements, it is particularly important to improve charging performance without changing the thickness of the wireless charging area. There are many factors that affect the performance of charging coils. Most existing charging coils use a double-sided single-strand parallel connection, that is, the charging coil group includes two layers of charging coils, which are connected in parallel. This coil setting method has weak mutual coupling between coils, and the quality factor Q value and inductance of the coil are low. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a series-parallel hybrid multi-layer and multi-strand wireless charging coil.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A hybrid series-parallel multi-layer multi-strand wireless charging coil comprises a coil bottom plate and a charging coil, wherein the coil bottom plate is provided with a lead-out terminal, a parallel hole and a via hole, wherein the charging coil comprises an outer ring parallel coil and an inner ring series coil, wherein the outer ring parallel coil comprises a first parallel coil arranged on the front side of the coil bottom plate and a second parallel coil arranged on the back side of the coil bottom plate, wherein the outer ring parallel coil and the inner ring series coil both comprise multi-strand coils, wherein the first parallel coil and the second parallel coil are connected in parallel with each other through the parallel hole and the order of strands is changed, wherein the inner ring series coil comprises a first series coil arranged on the front side of the coil bottom plate and a second series coil arranged on the back side of the coil bottom plate, wherein the first series coil is connected in series through the via hole and the order of strands is changed, and the current spiral directions of the outer ring parallel coil and the inner ring series coil are the same.

[0007] Preferably, the first parallel coil includes N coils with M turns of spiral winding, and correspondingly, the second parallel coil includes N coils with M turns of spiral winding, the first series coil includes N coils with P turns of spiral winding, and correspondingly, the second series coil includes N coils with P turns of spiral winding, wherein M and P are both greater than or equal to 1, N is greater than or equal to 2, the winding starting end of the outermost circle of the first parallel coil is connected to the lead-out end, the winding ending end of the innermost circle of the first parallel coil is connected to the winding starting end of the outermost circle of the first series coil, the winding ending end of the innermost circle of the first series coil is connected to the winding starting end of the innermost circle of the second series coil through a via, and the winding ending end of the outermost circle of the second series coil is connected to the lead-out end.

[0008] Preferably, the first parallel coil and the second parallel coil each include X parallel coil segments, the heads and tails of the corresponding parallel coil segments in the first parallel coil and the second parallel coil are respectively connected through parallel holes, some coils in the N strands of the adjacent parallel coil segments in the first parallel coil and the second parallel coil are replaced in order from the outside to the inside and then connected, and after the connection, current flows through each coil.

[0009] Preferably, the coil bottom plate is provided with N via holes, and the N strands of the first series coil are connected to the N strands of the second series coil through the via holes, and the N strands of the first series coil and the second series coil have different orders from outside to inside.

[0010] Preferably, a first lead-out terminal and a second lead-out terminal are provided on the front side of the coil bottom plate, and a third lead-out terminal is provided on the back side of the coil bottom plate. The second lead-out terminal and the third lead-out terminal are connected through a via, the first lead-out terminal is connected to the winding starting end of the outermost circle of the first parallel coil, and the third lead-out terminal is connected to the winding ending end of the outermost circle of the second series coil.

[0011] Preferably, the parallel holes are filled with conductive material.

[0012] Preferably, the coil base plate is an FPC coil base plate.

[0013] Preferably, the thickness of the FPC coil base plate ranges from 12 microns to 20 microns.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) The present invention uses a first parallel coil, a second parallel coil, a first series coil and a second series coil to form a double-layer series-parallel hybrid charging coil structure, and uses the hybrid form of series-parallel coils to improve the coupling between coil traces and improve the quality factor Q value, inductance and coupling coefficient of the coil;

[0016] (2) The first parallel coil and the second parallel coil of the present invention form a parallel coil strand switching structure through the parallel hole, and the first series coil and the second series coil form a series strand switching structure through the through hole, so that the coils are twisted and twisted to increase the mutual inductance between the coils;

[0017] (3) The present invention utilizes a parallel hole to connect the first parallel coil and the second parallel coil in parallel, and utilizes a via hole to connect the first series coil and the second series coil in series, without requiring an extra connection structure, thereby effectively saving space and improving the stability of the connection.

[0018] (4) The coil base plate used in the present invention is an FPC coil base plate, which is thin and easy to use, and effectively reduces the thickness and volume of the charging coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the front structure of Example 1 of the present invention;

[0020] Figure 2 It is a perspective view of the reverse structure of Example 1 of the present invention;

[0021] Figure 3 This is a schematic diagram of the front structure of Example 2 of the present invention;

[0022] Figure 4 It is a perspective view of the reverse structure of Example 2 of the present invention.

[0023] Among them, 1. coil bottom plate, 2. parallel hole, 3. via, 4. first parallel coil, 5. second parallel coil, 6. first series coil, 7. second series coil, 8. parallel coil segment, 9. first lead-out terminal, 10. second lead-out terminal, 11. third lead-out terminal. DETAILED DESCRIPTION

[0024] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the following embodiments are merely illustrative in nature, and the present invention is not intended to limit its applicable objects or uses, and the present invention is not limited to the following embodiments.

[0025] Example 1

[0026] A series-parallel hybrid multi-layer multi-strand wireless charging coil includes a coil base plate 1 and a charging coil. The coil base plate 1 is an FPC coil base plate. A first lead-out terminal 9 and a second lead-out terminal 10 are provided on the front side of the coil base plate 1. A third lead-out terminal 11 is provided on the back side of the coil base plate 1. A parallel hole 2 and a via 3 are opened through the coil base plate 1. The coil base plate 1 is an FPC coil base plate. The thickness of the coil base plate 1 ranges from 12 microns to 20 microns. The thickness of the FPC coil base plate used in this embodiment is 12.5 microns.

[0027] The charging coil includes an outer ring parallel coil and an inner ring series coil connected in series. The outer ring parallel coil and the inner ring series coil both include multiple coils. In this embodiment, the outer ring parallel coil and the inner ring series coil both include four coils. The outer ring parallel coil includes a first parallel coil 4 arranged on the front side of the coil bottom plate 1 and a second parallel coil 5 arranged on the back side of the coil bottom plate 1.

[0028] The current spiral directions of the outer parallel coil and the inner series coil are the same. Specifically, in this embodiment, the first parallel coil 4 includes 4 coils that are spirally wound for 1 circle, and correspondingly, the second parallel coil 5 includes 4 coils that are spirally wound for 1 circle, and the first series coil 6 includes 4 coils that are spirally wound for 4 circles, and correspondingly, the first series coil 6 includes 4 coils that are spirally wound for 4 circles, the winding starting end of the outermost circle of the first parallel coil 4 is connected to the first lead-out end, the winding ending end of the innermost circle of the first parallel coil 4 is connected to the winding starting end of the outermost circle of the first series coil 6, the winding ending end of the innermost circle of the first series coil 6 passes through the via 3 to be connected to the winding starting end of the innermost circle of the second series coil 7, and the winding ending end of the outermost circle of the second series coil 7 is connected to the third lead-out end.

[0029] The first parallel coil and the second parallel coil are connected in parallel to each other through the parallel hole and the order of strands is changed. In this embodiment, the first parallel coil 4 and the second parallel coil 5 each include 8 parallel coil segments 8, and the heads and tails of the corresponding parallel coil segments 8 in the first parallel coil 4 and the second parallel coil 5 are respectively connected through the parallel hole 2, and some coils in the 4 strands of the adjacent parallel coil segments 8 in the first parallel coil 4 and the second parallel coil 5 are connected after changing the order of the strands from the outside to the inside.

[0030] like Figure 1 , Figure 2As shown, in this embodiment, specifically, the first and second coil sections at the end of the first parallel coil segment 8 on the front side are connected to the third and fourth coil sections at the head end of the second parallel coil segment 8 on the front side, and correspondingly, the third and fourth coil sections at the end of the first parallel coil segment 8 on the back side are connected to the first and second coil sections at the head end of the second parallel coil segment 8 on the back side; the second and third coil sections at the end of the second parallel coil segment 8 on the front side are connected to the first and fourth coil sections at the head end of the second parallel coil segment 8 on the front side, and correspondingly, the first and fourth coil sections at the end of the second parallel coil segment 8 on the back side are connected to the first and fourth coil sections at the head end of the second parallel coil segment 8 on the front side. The coil section is connected to the second and third coils at the head end of the second parallel coil segment 8 on the back; the first, third and fourth coil sections at the end of the third parallel coil segment 8 on the front are connected to the first, second and fourth coils at the head end of the second parallel coil segment 8 on the front, and correspondingly, the first, second and fourth coil sections at the end of the third parallel coil segment 8 on the back are connected to the first, third and fourth coils at the head end of the third parallel coil segment 8 on the back; the third and fourth coil sections at the end of the fourth parallel coil segment 8 on the front are connected to the first and second coils at the head end of the second parallel coil segment 8 on the front, and correspondingly The first and second coil sections at the end of the fourth parallel coil segment 8 on the back are connected to the third and fourth coil sections at the beginning of the second parallel coil segment 8 on the back; the first, second and fourth coil sections at the end of the fifth parallel coil segment 8 on the front are connected to the first, third and fourth coil sections at the beginning of the second parallel coil segment 8 on the front, and correspondingly, the first, third and fourth coil sections at the end of the sixth parallel coil segment 8 on the back are connected to the first, second and fourth coil sections at the beginning of the second parallel coil segment 8 on the back; the first and fourth coil sections at the end of the sixth parallel coil segment 8 on the front are connected to the first The third and fourth coils at the head end of the second parallel coil segment 8, correspondingly, the second and third coils at the end of the sixth parallel coil segment 8 on the back are connected to the first and fourth coils at the head end of the second parallel coil segment 8 on the back; the first and second coils at the end of the seventh parallel coil segment 8 on the front are connected to the third and fourth coils at the head end of the second parallel coil segment 8 on the front, correspondingly, the third and fourth coils at the end of the seventh parallel coil segment 8 on the back are connected to the first and second coils at the head end of the second parallel coil segment 8 on the back, and after the connection, current flows through each coil.

[0031] The coil bottom plate 1 is provided with four vias 3, and the four coils of the first series coil 6 are connected to the four coils of the second series coil 7 through the vias 3. The order of the four coils of the first series coil 6 and the second series coil 7 from outside to inside is different, such as Figure 1 , Figure 2As shown, in this embodiment, specifically, the first coil of the first series coil 6 on the front side from the outside to the inside is connected to the fourth coil of the second series coil 7 on the back side, the second coil of the first series coil 6 on the front side from the outside to the inside is connected to the third coil of the second series coil 7 on the back side, the third coil of the first series coil 6 on the front side from the outside to the inside is connected to the second coil of the second series coil 7 on the back side, and the fourth coil of the first series coil 6 on the front side from the outside to the inside is connected to the first coil of the second series coil 7 on the back side.

[0032] In this embodiment, the single-strand parallel charging coil adopts a double-layer charging coil, and the first layer coil is connected in parallel with the second layer coil, and corresponding to this embodiment, the first layer coil and the second layer coil include four-strand coils with five turns. As shown in Table 1, after testing, the inductance, quality factor Q value, DC resistance, and AC resistance of the single-strand parallel charging coil and the charging coil of Example 1, the test results of this Example 1 are better than those of the single-strand parallel charging coil, and the specific formula of the quality factor Q value is: Q = 2πwL / Rac, where w is the frequency, L is the inductance, and Rac is the AC resistance. Specifically, in Table 1, Q = 2π*100kHz*L / Rac.

[0033] Table 1 Comparison between single-strand parallel coil and Example 1

[0034]

[0035] Example 2

[0036] like Figure 3 , Figure 4 A series-parallel hybrid multi-layer and multi-strand wireless charging coil is shown, comprising a coil base plate 1 and a charging coil. The coil base plate 1 is an FPC coil base plate. A first lead-out terminal 9 and a second lead-out terminal 10 are provided on the front side of the coil base plate 1, and a third lead-out terminal 11 is provided on the back side of the coil base plate 1. A parallel hole 2 and a via 3 are opened through the coil base plate 1. The coil base plate 1 is an FPC coil base plate. The thickness of the coil base plate 1 ranges from 12 microns to 20 microns. The thickness of the FPC coil base plate used in this embodiment is 12.5 microns.

[0037] The charging coil includes an outer ring parallel coil and an inner ring series coil, and the outer ring parallel coil and the inner ring series coil both include multiple coils. In this embodiment, the outer ring parallel coil and the inner ring series coil both include four coils, and the outer ring parallel coil includes a first parallel coil 4 arranged on the front side of the coil bottom plate 1 and a second parallel coil 5 arranged on the back side of the coil bottom plate 1.

[0038] The current spiral directions of the outer parallel coil and the inner series coil are the same. Specifically, in this embodiment, the first parallel coil 4 includes 4 coils with 2 spiral windings, and correspondingly, the second parallel coil 5 includes 4 coils with 2 spiral windings, and the first series coil 6 includes 4 coils with 4 spiral windings, and correspondingly, the first series coil 6 includes 4 coils with 4 spiral windings, and the outermost winding starting end of the first parallel coil 4 is connected to the first lead-out end, the innermost winding ending end of the first parallel coil 4 is connected to the outermost winding starting end of the first series coil 6, the innermost winding ending end of the first series coil 6 passes through the via 3 and is connected to the innermost winding starting end of the second series coil 7, and the outermost winding ending end of the second series coil 7 is connected to the third lead-out end.

[0039] The first parallel coil and the second parallel coil are connected in parallel to each other through the parallel hole and the order of strands is changed. In this embodiment, the first parallel coil 4 and the second parallel coil 5 each include 8 parallel coil segments 8, and the heads and tails of the corresponding parallel coil segments 8 in the first parallel coil 4 and the second parallel coil 5 are respectively connected through the parallel hole 2, and some coils in the 4 strands of the adjacent parallel coil segments 8 in the first parallel coil 4 and the second parallel coil 5 are connected after changing the order of the strands from the outside to the inside.

[0040] like Figure 3 , Figure 4As shown, in this embodiment, specifically, the first coil of the first parallel coil 4 and the second parallel coil 5 is connected in the following manner: the first and second coil sections at the end of the first parallel coil segment 8 on the front side are connected to the third and fourth coil sections at the head end of the second parallel coil segment 8 on the front side, and correspondingly, the third and fourth coil sections at the end of the first parallel coil segment 8 on the back side are connected to the first and second coil sections at the head end of the second parallel coil segment 8 on the back side; the second and third coil sections at the end of the second parallel coil segment 8 on the front side are connected to the first and fourth coil sections at the head end of the second parallel coil segment 8 on the front side, and the Correspondingly, the first and fourth coil sections at the end of the second parallel coil segment 8 on the back are connected to the second and third coil sections at the head end of the second parallel coil segment 8 on the back; the first, third and fourth coil sections at the end of the third parallel coil segment 8 on the front are connected to the first, second and fourth coil sections at the head end of the second parallel coil segment 8 on the front, and correspondingly, the first, second and fourth coil sections at the end of the third parallel coil segment 8 on the back are connected to the first, third and fourth coil sections at the head end of the third parallel coil segment 8 on the back; the third and fourth coil sections at the end of the fourth parallel coil segment 8 on the front are connected to the second The first and second coils at the head end of the first parallel coil segment 8 are connected to the third and fourth coils at the head end of the second parallel coil segment 8 on the back side; the first, second and fourth coils at the end of the fifth parallel coil segment 8 on the front side are connected to the first, third and fourth coils at the head end of the second parallel coil segment 8 on the front side, and the first, third and fourth coils at the end of the sixth parallel coil segment 8 on the back side are connected to the first, second and fourth coils at the head end of the second parallel coil segment 8 on the back side; the sixth parallel coil segment on the front side is connected to the The first and fourth coil sections at the end of 8 are connected to the third and fourth coils at the beginning of the second parallel coil segment 8 on the front side, and correspondingly, the second and third coil sections at the end of the sixth parallel coil segment 8 on the back side are connected to the first and fourth coils at the beginning of the second parallel coil segment 8 on the back side; the first and second coil sections at the end of the seventh parallel coil segment 8 on the front side are connected to the third and fourth coils at the beginning of the second parallel coil segment 8 on the front side, and correspondingly, the third and fourth coil sections at the end of the seventh parallel coil segment 8 on the back side are connected to the first and second coils at the beginning of the second parallel coil segment 8 on the back side.

[0041] The connection method of the second turns of the first parallel coil 4 and the second parallel coil 5 is the same as the connection method of the first turns of the first parallel coil 4 and the second parallel coil 5, and after the connection, current flows through each coil.

[0042] The coil bottom plate 1 is provided with four vias 3, and the four coils of the first series coil 6 are connected to the four coils of the second series coil 7 through the vias 3. The order of the four coils of the first series coil 6 and the second series coil 7 from outside to inside is different, such as Figure 3 , Figure 4As shown, in this embodiment, specifically, the first coil of the first series coil 6 on the front side from the outside to the inside is connected to the fourth coil of the second series coil 7 on the back side, the second coil of the first series coil 6 on the front side from the outside to the inside is connected to the third coil of the second series coil 7 on the back side, the third coil of the first series coil 6 on the front side from the outside to the inside is connected to the second coil of the second series coil 7 on the back side, and the fourth coil of the first series coil 6 on the front side from the outside to the inside is connected to the first coil of the second series coil 7 on the back side.

[0043] The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments can also be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the technical concept of the present invention.

Claims

1. A hybrid multi-layer and multi-strand wireless charging coil, characterized in that: The invention comprises a coil bottom plate (1) and a charging coil, wherein the coil bottom plate (1) is provided with a lead-out terminal, a parallel connection hole (2) and a through hole (3), wherein the charging coil comprises an outer ring parallel connection coil and an inner ring series connection coil connected in series, wherein the outer ring parallel connection coil comprises a first parallel connection coil (4) arranged on the front side of the coil bottom plate (1) and a second parallel connection coil (5) arranged on the back side of the coil bottom plate (1), wherein the outer ring parallel connection coil and the inner ring series connection coil both comprise a plurality of strands of coils, wherein the first parallel connection coil (4) and the second parallel connection coil (5) are mutually connected in parallel through the parallel connection hole (2) and the order of the strands is changed, wherein the inner ring series connection coil comprises a first series connection coil (6) arranged on the front side of the coil bottom plate (1) and a second series connection coil (7) arranged on the back side of the coil bottom plate (1), wherein the first series connection coil (6) is connected in series through the through hole (3) and the order of the strands is changed, and the current spiral directions of the outer ring parallel connection coil and the inner ring series connection coil are the same; The first parallel coil (4) includes an N-strand coil with M turns of spiral winding, and correspondingly, the second parallel coil (5) includes an N-strand coil with M turns of spiral winding, the first series coil (6) includes an N-strand coil with P turns of spiral winding, and correspondingly, the second series coil (7) includes an N-strand coil with P turns of spiral winding, wherein M and P are both greater than or equal to 1, and N is greater than or equal to 2, the winding start end of the outermost turn of the first parallel coil (4) is connected to the lead-out end, the winding end end of the innermost turn of the first parallel coil (4) is connected to the winding start end of the outermost turn of the first series coil (6), the winding end end of the innermost turn of the first series coil (6) passes through the via (3) and is connected to the winding start end of the innermost turn of the second series coil (7), and the winding end end of the outermost turn of the second series coil (7) is connected to the lead-out end; The first parallel coil (4) and the second parallel coil (5) each include X parallel coil segments (8), wherein X is greater than or equal to 2, the head and tail of the corresponding parallel coil segments (8) in the first parallel coil (4) and the second parallel coil (5) are connected through the parallel holes (2) respectively, and some coils in the N strands of the adjacent parallel coil segments (8) in the first parallel coil (4) and the second parallel coil (5) are connected after the coils are replaced in order from the outside to the inside, and after the connection, current flows through each coil; The coil bottom plate (1) is provided with N through holes (3), and the N strands of the first series coil (6) are connected to the N strands of the second series coil (7) through the through holes (3), and the N strands of the first series coil (6) and the second series coil (7) have different strand order from outside to inside; The parallel holes (2) are filled with conductive material.

2. The serial-parallel hybrid multi-layer multi-strand wireless charging coil according to claim 1, characterized in that: A first lead-out terminal (9) and a second lead-out terminal (10) are provided on the front side of the coil bottom plate (1), and a third lead-out terminal (11) is provided on the back side of the coil bottom plate (1). The second lead-out terminal (10) and the third lead-out terminal (11) are connected via a via (3). The first lead-out terminal (9) is connected to the winding start end of the outermost turn of the first parallel coil (4), and the third lead-out terminal (11) is connected to the winding end end of the outermost turn of the second series coil (7).

3. The serial-parallel hybrid multi-layer multi-strand wireless charging coil according to claim 1, characterized in that: The coil bottom plate (1) is an FPC coil bottom plate.

4. The serial-parallel hybrid multi-layer multi-strand wireless charging coil according to claim 3, characterized in that: The thickness of the coil bottom plate (1) ranges from 12 microns to 20 microns.

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