Vehicle-mounted wireless charging device and method

Abstract

The invention provides a vehicle-mounted wireless charging device and method.The vehicle-mounted wireless charging device comprises a shell, a wireless charging antenna array and a control mainboard, the wireless charging antenna array and the control mainboard are arranged in the shell, the wireless charging antenna array is electrically connected with the control mainboard, and a charging tray is arranged at the position, corresponding to the wireless charging antenna array, of the shell; the wireless charging antenna array comprises a first main coil, a second main coil and an auxiliary coil; the first main coil and the second main coil serve as a bottom layer and are arranged at an interval, the auxiliary coil serves as a top layer and is stacked on the tops of the first main coil and the second main coil, and the opposite sides of the first main coil and the second main coil have overlapping areas with the auxiliary coil; the first main coil, the second main coil and the auxiliary coil are runway type coils. The vehicle-mounted charging system has the advantages that simultaneous charging of multiple terminal devices can be well supported, switching between fast charging and slow charging can be achieved, and the actual vehicle-mounted use requirement can be well met.

Description

[Technical field]

[0001] The present invention relates to the technical field of vehicle-mounted wireless charging, and in particular to a vehicle-mounted wireless charging device and method. [Background technology]

[0002] Wireless charging technology has gradually penetrated into multiple fields such as smartphones, wearable devices, automotive electronics, and household appliances. In the future, efficient and long-distance wireless charging technology will be widely used and further enhance user experience. For example, the Qi 2.1 in-car wireless charging technology launched by WPC solves the charging problem caused by the movement of mobile phones and improves the charging effect and stability.

[0003] There are two mainstream wireless charging technology routes, one is the inductive coupling route, and the other is the magnetic resonance route. Both routes have their own advantages. At present, the mainstream vehicle-mounted communication technology is still dominated by inductive coupling technology. The biggest advantage of inductive coupling technology is that it supports variable power charging, which makes the switching efficiency between fast charging and ordinary charging relatively high. However, existing vehicle-mounted charging devices usually only have a single coil, which can only support charging of a single terminal device, and cannot support charging of multiple terminal devices at the same time. The main reason is that the simple arrangement of multiple coils will have strong electromagnetic interference with each other, which will greatly reduce the charging efficiency, or even cause charging failure. In view of the above-mentioned problems, the inventor of this case conducted an in-depth study on the problem, and thus this case came into being. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to provide a vehicle-mounted wireless charging device and method to solve the problem that the existing vehicle-mounted charging device cannot support charging of multiple terminal devices at the same time.

[0005] The present invention is implemented as follows: an in-vehicle wireless charging device comprises a housing, a wireless charging antenna array and a control mainboard arranged in the housing, the wireless charging antenna array is electrically connected to the control mainboard, and a charging tray is arranged on the housing at a position corresponding to the wireless charging antenna array;

[0006] The wireless charging antenna array includes a first main coil, a second main coil and an auxiliary coil; the first main coil and the second main coil serve as the bottom layer and are spaced apart, the auxiliary coil serves as the top layer and is stacked on top of the first main coil and the second main coil, and the first main coil and the second main coil have an overlapping area on one side facing each other with the auxiliary coil; the first main coil, the second main coil and the auxiliary coil are all runway-type coils.

[0007] Furthermore, the first main coil, the second main coil and the auxiliary coil are all wound with 12 turns.

[0008] Furthermore, the parameters of the first main coil, the second main coil and the auxiliary coil are as follows:

[0009] Lp: 10uH±10%;

[0010] Q: 80 (Min);

[0011] DCR: 60mΩ.

[0012] Furthermore, the center points of the first main coil, the second main coil and the auxiliary coil are located on the same straight line, and the distance between the center point of the auxiliary coil and the center point of the first main coil is 25±0.5mm, and the distance between the center point of the auxiliary coil and the center point of the second main coil is 25±0.5mm.

[0013] Furthermore, the distance between the first main coil and the second main coil is 10±0.5 mm.

[0014] Furthermore, the overall length of the first main coil, the second main coil and the auxiliary coil is 50±1 mm, and the overall width of the first main coil, the second main coil and the auxiliary coil is 40±1 mm.

[0015] In a second aspect, a charging method for a vehicle-mounted wireless charging device is provided, the charging method comprising the following steps:

[0016] Divide the charging area on the charging tray into a first area and a second area, wherein the first area covers the first main coil and the auxiliary coil, and the second area covers the second main coil and the auxiliary coil;

[0017] The magnetic field strength of the first area and the second area is detected, and the first main coil, the second main coil and the auxiliary coil are controlled to work according to the magnetic field strength of the first area and the second area and the selected charging mode.

[0018] Furthermore, the controlling the first main coil, the second main coil and the auxiliary coil to work according to the magnetic field strength of the first area and the second area and the selected charging mode specifically includes:

[0019] When the selected charging mode is the fast charging mode, if it is detected that the magnetic field strengths of the first area and the second area both reach the set threshold, the first main coil, the second main coil and the auxiliary coil are controlled to work simultaneously; if it is detected that the magnetic field strength of the first area reaches the set threshold and the magnetic field strength of the second area does not reach the set threshold, the first main coil and the auxiliary coil are controlled to work simultaneously; if it is detected that the magnetic field strength of the second area reaches the set threshold and the magnetic field strength of the first area does not reach the set threshold, the second main coil and the auxiliary coil are controlled to work simultaneously; if it is detected that the magnetic field strengths of the first area and the second area do not reach the set threshold, the first main coil, the second main coil and the auxiliary coil are all stopped from working;

[0020] When the selected charging mode is the slow charging mode, if it is detected that the magnetic field strengths of the first area and the second area both reach the set threshold, the first main coil and the second main coil are controlled to work simultaneously; if it is detected that the magnetic field strength of the first area reaches the set threshold and the magnetic field strength of the second area does not reach the set threshold, the first main coil is controlled to work; if it is detected that the magnetic field strength of the second area reaches the set threshold and the magnetic field strength of the first area does not reach the set threshold, the second main coil is controlled to work; if it is detected that the magnetic field strength of the first area and the second area does not reach the set threshold, the first main coil, the second main coil and the auxiliary coil are all stopped from working.

[0021] Furthermore, the first area is divided by a side of the auxiliary coil away from the first main coil, and the second area is divided by a side of the auxiliary coil away from the second main coil.

[0022] By adopting the technical solution of the present invention, at least the following beneficial effects are achieved: the single-coil structural design of the existing vehicle-mounted wireless charging device is completely changed, and a wireless charging antenna array is formed by designing and utilizing three coils, and the positions of the three coils present a two-layer structural design, and the shapes of the three coils are designed to be runway-shaped structures, and the number of turns of the three coils is 12 turns; by adopting the above structural design, the magnetic field distribution can be effectively improved, and the electromagnetic interference generated between the first main coil, the second main coil and the auxiliary coil is greatly reduced, so that the waveform formed by the first main coil, the second main coil and the auxiliary coil after stacking is more concentrated and the magnetic field distribution is stronger. Therefore, it is not only possible to well support multiple terminal devices for simultaneous charging, but also possible to realize switching between fast charging and slow charging, which can well meet the actual vehicle-mounted use needs.

Brief Description of the Drawings

[0023] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0024] Figure 1 is a schematic diagram of a first area on a vehicle-mounted wireless charging device of the present invention;

[0025] Figure 2 is a schematic diagram of a second area on a vehicle-mounted wireless charging device of the present invention;

[0026] Figure 3 is a structural diagram of the wireless charging antenna array of the present invention;

[0027] Figure 4 is the directional pattern of a general antenna;

[0028] Figure 5 It is the directional pattern of the antenna array formed by stacking three racetrack-shaped coils with 12 turns (i.e., the first main coil, the second main coil, and the auxiliary coil) in the invention;

[0029] Figure 6 It is a directional pattern that uses a single racetrack-shaped coil as the antenna;

[0030] Figure 7 The directional pattern of the antenna array is formed by the first main coil and the second main coil both using racetrack-shaped coils, and the auxiliary coil using a circular ring coil;

[0031] Figure 8 It is the directional pattern of the antenna array formed after the auxiliary coil is translated to a certain position;

[0032] Fig. 9 It is the directional pattern of the antenna array formed by stacking three racetrack-shaped coils with 10 turns each.

[0033] Description of reference numerals:

[0034] A vehicle-mounted wireless charging device 100;

[0035] Wireless charging antenna array 200;

[0036] Housing 1, charging tray 11;

[0037] The first main coil 2;

[0038] The second main coil 3;

[0039] Auxiliary coil 4

[0040] Terminal block 5;

[0041] First area A;

[0042] Second area B. [Specific implementation method]

[0043] In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0044] It should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing these embodiments and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. In addition, the terms "first", "second", etc., etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0045] Embodiment 1

[0046] See also Figures 1 to 3 As shown, the present invention provides an on-vehicle wireless charging device 100, which includes a housing 1, a wireless charging antenna array 200 and a control mainboard (not shown) arranged in the housing 1, wherein the wireless charging antenna array 200 is electrically connected to the control mainboard so as to control the wireless charging antenna array 200 to work through the control mainboard, and a charging tray 11 is arranged on the housing 1 at a position corresponding to the wireless charging antenna array 200, so as to facilitate placing a terminal device on the charging tray 11 for charging;

[0047] The wireless charging antenna array 200 includes a first main coil 2, a second main coil 3 and an auxiliary coil 4, wherein the first main coil 2 and the second main coil 3 are used to realize low-voltage charging (i.e., slow charging), and the auxiliary coil 4 is used to cooperate with the first main coil 2 and / or the second main coil 3 to realize high-voltage charging (i.e., fast charging); the first main coil 2 and the second main coil 3 are used as the bottom layer and are arranged at a distance, and the auxiliary coil 4 is used as the top layer and is stacked on the top of the first main coil 2 and the second main coil 3, and the first main coil 2 and the second main coil 3 have an overlapping area on the side facing each other with the auxiliary coil 4, that is, the wireless charging antenna array 200 in the present invention adopts a two-layer structural design, with the first main coil 2 and the second main coil 3 used for providing low-voltage electricity as the bottom layer, and the auxiliary coil 4 as the top layer and directly stacked on the first main coil 2 and the second main coil 3; the first main coil 2, the second main coil 3 and the auxiliary coil 4 are all runway-type coils.

[0048] In the present invention, the number of turns of the first main coil 2, the second main coil 3 and the auxiliary coil 4 are all 12. In the specific implementation of the present invention, the first main coil 2, the second main coil 3 and the auxiliary coil 4 can be formed by winding varnished copper wire.

[0049] The existing single-coil vehicle-mounted wireless charging device uses a 0.4mm diameter enameled copper wire, which is wrapped 10 times in total, and the coil is in a circular ring structure. In the actual design process, if multiple coils are simply designed in parallel, it will cause great electromagnetic interference, which will greatly reduce the efficiency of wireless charging and even make wireless charging impossible. This is also the core reason why the existing vehicle-mounted wireless charging device can only support charging of a single terminal device.

[0050] Because in the specific implementation process, the length (i.e. the number of windings), shape, and stacking position of the antenna will have a significant impact on the magnetic field distribution. To this end, the present invention completely changes the single-coil structural design of the existing vehicle-mounted wireless charging device, and forms a wireless charging antenna array 200 by designing and utilizing three coils, and the positions of the three coils present a two-layer structural design. At the same time, the shapes of the three coils are designed to be runway-shaped structures, and the number of turns of the three coils is 12; by adopting the above structural design, the magnetic field distribution can be effectively improved, and the electromagnetic interference generated between the first main coil 2, the second main coil 3, and the auxiliary coil 4 can be greatly reduced, so that the waveform formed by the first main coil 2, the second main coil 3, and the auxiliary coil 4 after stacking is more concentrated, and the magnetic field distribution is stronger. Therefore, it can not only well support multiple terminal devices to charge at the same time, but also realize fast charging and slow charging switching, which can well meet the actual use needs of the vehicle.

[0051] In the present invention, in order to further ensure the magnetic field distribution effect of the first main coil 2, the second main coil 3 and the auxiliary coil 4 after stacking, the parameters of the first main coil 2, the second main coil 3 and the auxiliary coil 4 are as follows:

[0052] Lp: 10uH±10%;

[0053] Q: 80 (Min), that is, under the minimum working condition, the coil's electricity is 80 units;

[0054] DCR: 60mΩ, that is, the resistance per unit length of the coil is 60mΩ;

[0055] It should be noted that: in the above parameters, Lp represents inductance, Q represents charge, and DCR represents resistance per unit length.

[0056] In a preferred embodiment of the present invention, the center points of the first main coil 2, the second main coil 3 and the auxiliary coil 4 are located on the same straight line, and the distance between the center point of the auxiliary coil 4 and the center point of the first main coil 2 is 25±0.5mm, and the distance between the center point of the auxiliary coil 4 and the center point of the second main coil 3 is 25±0.5mm.

[0057] In a preferred embodiment of the present invention, the distance between the first main coil and the second main coil is 10±0.5 mm.

[0058] After a large number of experiments, the applicant found that the spacing between the first main coil 2 and the second main coil 3 and the stacking position of the auxiliary coil 4 will also have a certain impact on the magnetic field distribution. To this end, the present invention designs the spacing between the first main coil 2 and the second main coil 3 to be 10±0.5mm, and makes the center points of the first main coil 2, the second main coil 3 and the auxiliary coil 4 on the same straight line, and at the same time designs the distance between the center point of the auxiliary coil 4 and the center points of the first main coil 2 and the second main coil 3 to be 25±0.5mm, which can further improve the magnetic field distribution and ensure that the waveform formed by the entire wireless charging antenna array 200 is more concentrated and the magnetic field distribution is stronger.

[0059] As a preferred embodiment of the present invention, the overall length of the first main coil 2, the second main coil 3 and the auxiliary coil 4 is 50±1mm, and the overall width of the first main coil 2, the second main coil 3 and the auxiliary coil 4 is 40±1mm; at the same time, the width of the innermost circle of the first main coil 2, the second main coil 3 and the auxiliary coil 4 can be designed to be 20±0.5mm; of course, the above specific size design is only a preferred embodiment of the present invention, but the present invention is not limited thereto, and the specific size can be adjusted according to actual needs during specific implementation. In addition, during the specific implementation of the present invention, the length direction of the auxiliary coil 4 can be designed to be parallel to the width direction of the first main coil 2 and the second main coil 3.

[0060] In the specific implementation of the present invention, in order to facilitate the electrical connection of the first main coil 2, the second main coil 3 and the auxiliary coil 4 with the control main board, the first main coil 2, the second main coil 3 and the auxiliary coil 4 are extended outward to form two wiring terminals 5.

[0061] Embodiment 2

[0062] See also Figures 1 to 3 As shown, the present invention provides a charging method for a vehicle-mounted wireless charging device 100, wherein the specific structure and the beneficial effects that can be obtained by the vehicle-mounted wireless charging device 100 are exactly the same as those of the first embodiment, and please refer to the detailed description of the first embodiment for details; the charging method comprises the following steps:

[0063] Step S1, dividing the charging area on the charging tray 11 into a first area A and a second area B, wherein the first area A covers the first main coil 2 and the auxiliary coil 4, and the second area B covers the second main coil 3 and the auxiliary coil 4, so as to ensure that the first main coil 2 can cooperate with the auxiliary coil 4 to charge the terminal device placed in the first area A, and similarly, the second main coil 3 can cooperate with the auxiliary coil 4 to charge the terminal device placed in the second area B;

[0064] Step S2, detecting the magnetic field strength of the first area A and the second area B, and controlling the first main coil 2, the second main coil 3 and the auxiliary coil 4 to work according to the magnetic field strength of the first area A and the second area B and the selected charging mode. In the specific implementation of the present invention, when the terminal device is placed on the first area A and / or the second area B, the detection circuit provided in the vehicle-mounted wireless charging device 100 can be used to detect the magnetic field strength of the first area A and the second area B, and the first main coil 2, the second main coil 3 and the auxiliary coil 4 can be controlled to work according to the detection result and the selected charging mode.

[0065] In the present invention, the controlling of the first main coil 2, the second main coil 3 and the auxiliary coil 4 to work according to the magnetic field strength of the first area A and the second area B and the selected charging mode specifically includes:

[0066] When the selected charging mode is the fast charging mode, if it is detected that the magnetic field strengths of the first area A and the second area B both reach the set threshold, which can be set according to actual use needs, the first main coil 2, the second main coil 3 and the auxiliary coil 4 are controlled to work simultaneously, that is, when the magnetic field strengths of the first area A and the second area B both reach the set threshold, it means that terminal devices are placed in the first area A and the second area B. At this time, the first main coil 2, the second main coil 3 and the auxiliary coil 4 are controlled to work simultaneously, which can realize fast charging of multiple terminal devices; if it is detected that the magnetic field strength of the first area A reaches the set threshold and the magnetic field strength of the second area B does not reach If the magnetic field strength of the second area B reaches the set threshold and the magnetic field strength of the first area A does not reach the set threshold, the second main coil 3 and the auxiliary coil 4 are controlled to work simultaneously to realize fast charging of at least one terminal device placed in the second area B; if it is detected that the magnetic field strength of the first area A and the second area B does not reach the set threshold, it is controlled that the second main coil 3 and the auxiliary coil 4 work simultaneously to realize fast charging of at least one terminal device placed in the second area B; if it is detected that the magnetic field strength of both the first area A and the second area B does not reach the set threshold, it means that no terminal device is placed in the first area A and the second area B, and the first main coil 2, the second main coil 3 and the auxiliary coil 4 are all stopped from working;

[0067] When the selected charging mode is the slow charging mode, if it is detected that the magnetic field strengths of the first area A and the second area B both reach the set threshold, the first main coil 2 and the second main coil 3 are controlled to work simultaneously to realize slow charging of multiple terminal devices placed in the first area A and the second area B. At the same time, because the selected charging mode is the slow charging mode, the auxiliary coil 4 does not work in this mode; if it is detected that the magnetic field strength of the first area A reaches the set threshold and the magnetic field strength of the second area B does not reach the set threshold, the first main coil 2 is controlled to work to realize slow charging of at least one terminal device placed in the first area A; if it is detected that the magnetic field strength of the second area B reaches the set threshold and the magnetic field strength of the first area A does not reach the set threshold, the second main coil 3 is controlled to work to realize slow charging of at least one terminal device placed in the second area B; if it is detected that the magnetic field strengths of the first area A and the second area B do not reach the set threshold, it means that no terminal device is placed in the first area A and the second area B, so the first main coil 2, the second main coil 3 and the auxiliary coil 4 are all stopped from working.

[0068] As a preferred embodiment of the present invention, in order to ensure the actual charging effect, the first area A uses the side of the auxiliary coil 4 away from the first main coil 2 as the dividing line, and the second area B uses the side of the auxiliary coil 4 away from the second main coil 3 as the dividing line.

[0069] The wireless charging antenna array 100 of the present invention is further described in detail below in conjunction with the antenna directional diagram:

[0070] The current on the antenna surface radiates through the medium and generates an electromagnetic field in the far field. Specifically, the far field electromagnetic field can be represented by a spherical coordinate system. The radiation pattern is a quantitative relationship diagram used to describe the change of a certain antenna parameter with the azimuth angle. The far field amplitude or gain of the antenna can be reflected very intuitively according to the radiation pattern; the radiation pattern can be a 3D radiation pattern or a 2D polar coordinate radiation pattern. The present invention uses a 2D diagram to represent the direction of the magnetic field.

[0071] Other concepts about directional patterns. Figure 4 As shown in the figure, the directional pattern of a general antenna has more than two lobes, among which the strongest level lobe in the field strength direction is the main lobe, the other lobes are side lobes, and the lobe opposite to the main lobe is called the back lobe. The maximum radiation direction of the main lobe is the point where the radiation intensity on both sides of the vertex decreases by 3dB, and the angle between the two sides is called the main lobe width; the smaller the main lobe width, the better the directivity of the antenna, the more concentrated the energy, and the stronger the directivity, while the side lobe represents the energy spreading in the direction we don't need, which is what we don't want, so the generation of side lobes should be reduced.

[0072] like Figure 5 and Figure 6 As shown: Figure 5It is the directional diagram of the antenna array formed by stacking three racetrack-shaped coils with 12 turns (i.e., the first main coil 2, the second main coil 3, and the auxiliary coil 4) in the present invention; Figure 6 It is a directional pattern using a single racetrack coil as the antenna. Figure 5 and Figure 6 From the comparison, it can be seen intuitively that the waveform of the three stacked racetrack coils is more concentrated and the magnetic field distribution is stronger, which is the basis for achieving fast and slow impulse.

[0073] like Figure 5 and Figure 7 As shown: Figure 5 It is the directional diagram of the antenna array formed by stacking three racetrack-shaped coils with 12 turns (i.e., the first main coil 2, the second main coil 3, and the auxiliary coil 4) in the present invention; Figure 7 The first main coil and the second main coil are both racetrack coils, while the auxiliary coil is a circular coil to form the antenna array directional pattern. Figure 5 and Figure 7 The comparison shows intuitively that when the shape of the auxiliary coil changes, the direction of the antenna main lobe will have an angular shift, which will cause a significant attenuation of the magnetic field strength in the charging direction.

[0074] like Figure 5 and Figure 8 As shown: Figure 5 It is the directional diagram of the antenna array formed by stacking three racetrack-shaped coils with 12 turns (i.e., the first main coil 2, the second main coil 3, and the auxiliary coil 4) in the present invention; Figure 8 It is the directional pattern of the antenna array formed after the auxiliary coil is translated to a certain position. Specifically, it is a directional pattern with better distribution selected after the auxiliary coil is translated to outside the range specified by the present invention. In specific implementation, when the auxiliary coil is translated to a certain position for placement, the magnetic field distribution will also undergo a relatively large change, such as by Figure 5 and Figure 8 By comparison, it can be seen that after the auxiliary coil is translated, the field strength attenuates from 20dB to about 10dB, and the side lobes also become larger.

[0075] like Figure 5 and Fig. 9 As shown: Figure 5 It is the directional diagram of the antenna array formed by stacking three racetrack-shaped coils with 12 turns (i.e., the first main coil 2, the second main coil 3, and the auxiliary coil 4) in the present invention; Fig. 9 This is the directional pattern of the antenna array formed by stacking three racetrack coils with 10 turns each. Figure 3 and Figure 7The comparison shows intuitively that when the number of turns of the racetrack coil changes from 12 to 10, the field strength decays from 20dB to about 10dB, and the side lobes also become larger.

[0076] From the above comparison, it can be seen that the length (i.e. the number of windings), shape, and stacking position of the antenna are very important for the magnetic field distribution. The present invention forms a wireless charging antenna array 200 by designing a two-layer structure stacked by the first main coil 2, the second main coil 3, and the auxiliary coil 4, and cleverly designs the shape, length, and stacking position of the first main coil 2, the second main coil 3, and the auxiliary coil 4. It can ensure that the waveform formed by the first main coil 2, the second main coil 3, and the auxiliary coil 4 after stacking is more concentrated and the magnetic field distribution is stronger, so that it can well support multiple terminal devices to charge simultaneously and meet the use requirements of fast charging and slow charging.

[0077] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A vehicle-mounted wireless charging device, characterized in that: It includes a shell, a wireless charging antenna array and a control mainboard arranged in the shell, the wireless charging antenna array is electrically connected to the control mainboard, and a charging tray is arranged on the shell at a position corresponding to the wireless charging antenna array; The wireless charging antenna array includes a first main coil, a second main coil and an auxiliary coil; the first main coil and the second main coil serve as the bottom layer and are spaced apart, the auxiliary coil serves as the top layer and is stacked on top of the first main coil and the second main coil, and the first main coil and the second main coil have an overlapping area on one side facing each other with the auxiliary coil; the first main coil, the second main coil and the auxiliary coil are all runway-type coils.

2. The vehicle-mounted wireless charging device according to claim 1, characterized in that: The first main coil, the second main coil and the auxiliary coil are all wound 12 times.

3. The vehicle-mounted wireless charging device according to claim 1, characterized in that: The parameters of the first main coil, the second main coil and the auxiliary coil are as follows: Lp: 10uH±10%; Q: 80 (Min); DCR: 60mΩ.

4. The vehicle-mounted wireless charging device according to claim 1, characterized in that: The center points of the first main coil, the second main coil and the auxiliary coil are located on the same straight line, and the distance between the center point of the auxiliary coil and the center point of the first main coil is 25±0.5mm, and the distance between the center point of the auxiliary coil and the center point of the second main coil is 25±0.5mm.

5. The vehicle-mounted wireless charging device according to claim 1, characterized in that: The distance between the first main coil and the second main coil is 10±0.5 mm.

6. The vehicle-mounted wireless charging device according to claim 1, characterized in that: The overall length of the first main coil, the second main coil and the auxiliary coil is 50±1 mm, and the overall width of the first main coil, the second main coil and the auxiliary coil is 40±1 mm.

7. A charging method based on the vehicle-mounted wireless charging device according to any one of claims 1 to 6, characterized in that: The charging method comprises the following steps: Divide the charging area on the charging tray into a first area and a second area, wherein the first area covers the first main coil and the auxiliary coil, and the second area covers the second main coil and the auxiliary coil; The magnetic field strength of the first area and the second area is detected, and the first main coil, the second main coil and the auxiliary coil are controlled to work according to the magnetic field strength of the first area and the second area and the selected charging mode.

8. A charging method for a vehicle-mounted wireless charging device as claimed in claim 7, characterized in that: The controlling the first main coil, the second main coil and the auxiliary coil to work according to the magnetic field strength of the first area and the second area and the selected charging mode specifically includes: When the selected charging mode is the fast charging mode, if it is detected that the magnetic field strengths of the first area and the second area both reach the set threshold, the first main coil, the second main coil and the auxiliary coil are controlled to work simultaneously; if it is detected that the magnetic field strength of the first area reaches the set threshold and the magnetic field strength of the second area does not reach the set threshold, the first main coil and the auxiliary coil are controlled to work simultaneously; if it is detected that the magnetic field strength of the second area reaches the set threshold and the magnetic field strength of the first area does not reach the set threshold, the second main coil and the auxiliary coil are controlled to work simultaneously; if it is detected that the magnetic field strengths of the first area and the second area do not reach the set threshold, the first main coil, the second main coil and the auxiliary coil are all stopped from working; When the selected charging mode is the slow charging mode, if it is detected that the magnetic field strengths of the first area and the second area both reach the set threshold, the first main coil and the second main coil are controlled to work simultaneously; if it is detected that the magnetic field strength of the first area reaches the set threshold and the magnetic field strength of the second area does not reach the set threshold, the first main coil is controlled to work; if it is detected that the magnetic field strength of the second area reaches the set threshold and the magnetic field strength of the first area does not reach the set threshold, the second main coil is controlled to work; if it is detected that the magnetic field strength of the first area and the second area does not reach the set threshold, the first main coil, the second main coil and the auxiliary coil are all stopped from working.

9. The charging method of a vehicle-mounted wireless charging device according to claim 7, characterized in that: The first area is divided by a side of the auxiliary coil away from the first main coil, and the second area is divided by a side of the auxiliary coil away from the second main coil.

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