Wireless charging device capable of reducing eddy current

Abstract

The utility model relates to the technical field of wireless charging, and discloses a wireless charging device capable of reducing eddy current, which comprises a first soft magnet, a receiving coil, a flexible circuit board, a second soft magnet and a connecting piece, and is characterized in that the first soft magnet is provided with a first through hole; the receiving coil is arranged below the first soft magnet, a first connecting end on the inner side of the receiving coil is positioned below the first through hole, and a second connecting end on the outer side is close to the edge part of the first soft magnet; an inner wire circuit of the flexible circuit board is located above the first soft magnet and connected with the first connecting end after passing through the first through hole, and an outer wire circuit is located below the first soft magnet and connected with the second connecting end. The second soft magnet is arranged above the first soft magnet and covers a position where the inner wire circuit is connected with the first connecting end; the connecting piece is arranged on the side, away from the first soft magnet, of the receiving coil. According to the utility model, the eddy current formed in the wireless charging device is reduced, the heating value of an electronic product is reduced, and the wireless charging efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of wireless charging technology, and in particular to a wireless charging device that reduces eddy currents. Background Technology

[0002] The main components of a wireless charging device are a receiving coil, a soft magnet, and a circuit board. The wireless charging device is built into the electronic product being charged, such as a mobile phone, tablet, or smartwatch. When the electronic product is brought close to the charging base, the transmitting coil in the charging base, based on alternating current of a certain frequency, induces a current in the receiving coil of the electronic product through electromagnetic induction. This transmits energy from the transmitting end to the receiving end, thus charging the electronic product. Because a current is generated at the receiving end, the electronic product being charged will generate heat, causing a temperature rise problem. In severe cases, this can lead to the electronic product overheating, malfunction, or even explosion.

[0003] In order to minimize the temperature rise of electronic products being charged, the main charging method for mobile phones, tablets and other electronic products in the current technology is to limit the charging current of the circuit. Limiting the current will result in low charging efficiency of electronic products. As a result, users will feel that although the product is no longer hot, the charging is obviously slower, which will reduce the user's satisfaction.

[0004] Given the prevalence of these problems in electronic products on the market, there is an urgent need for a wireless charging device that reduces eddy currents to solve these technical issues. Utility Model Content

[0005] Based on the above, the purpose of this utility model is to provide a wireless charging device that reduces eddy currents, thereby reducing the temperature rise of electronic products during wireless charging and improving the charging efficiency of electronic products.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A wireless charging device that reduces eddy currents includes:

[0008] A first soft magnet, wherein a first through hole is formed on the upper and lower surfaces of the first soft magnet;

[0009] A receiving coil is disposed below the first soft magnet. The receiving coil includes a first connecting end wound on the inner side and a second connecting end wound on the outer side. The first connecting end is located below the first through hole, and the second connecting end is close to the edge of the first soft magnet.

[0010] A flexible circuit board includes inner conductor lines and outer conductor lines. The inner conductor lines are located above the first soft magnet and connected to the first connection end after passing through the first through hole. The outer conductor lines are located below the first soft magnet and connected to the second connection end.

[0011] The second soft magnet is disposed above the first soft magnet and covers the area above the connection point between the inner conductor and the first connection end.

[0012] A connector is provided on the side of the receiving coil away from the first soft magnet, for fixing it to an electronic product.

[0013] In some possible implementations, the coverage area of ​​the first soft magnet is larger than the coverage area of ​​the receiving coil, and the coverage area of ​​the second soft magnet is smaller than the coverage area of ​​the receiving coil.

[0014] In some possible implementations, the internal conductor lines of the flexible circuit board include multiple sub-lines arranged in parallel.

[0015] In some possible implementations, the internal conductor lines of the flexible circuit board are Litz wire or self-adhesive enameled wire.

[0016] In some possible implementations, the connector is a colloid or Mylar.

[0017] In some possible implementations, the connector is sheet-like, and the shape of the connector is the same as that of the first soft magnet.

[0018] In some possible implementations, a second through hole is formed on the first soft magnet, penetrating its upper and lower surfaces, for fixing it to an electronic product by fasteners.

[0019] In some possible implementations, the receiving coil is fixed to the first soft magnet, the first soft magnet is fixed to the flexible circuit board, and the second soft magnet is fixed to the first soft magnet by adhesive bonding.

[0020] In some possible implementations, the wireless charging device further includes a graphite heat sink for dissipating heat from the receiving coil.

[0021] In some possible implementations, both the first soft magnet and the second soft magnet are made of nanocrystalline materials or ferrite.

[0022] The beneficial effects of this utility model are:

[0023] This invention provides a wireless charging device for reducing eddy currents. The inner and outer wires of a flexible circuit board are respectively placed on the upper and lower sides of a first soft magnet. The inner wire is located above the first soft magnet, and the outer wire is located below it. The inner wire passes through a first through-hole and connects to a first connecting end coiled inside the receiving coil below the first soft magnet. The outer wire connects to a second connecting end coiled outside the receiving coil. Since eddy currents are easily generated in the inner wires of a flexible circuit board, this invention uses the first soft magnet to separate the inner wires from the receiving coil, thereby reducing the eddy currents formed by the magnetic field of the receiving coil on the inner wires. This effectively reduces the heat generated by the wireless charging device, lowers the temperature rise of electronic products during charging, and improves the user experience and charging safety. Furthermore, by placing a second soft magnet above the inner wires, this invention can shield the leakage magnetic field of the receiving coil at the first through-hole, further improving the electromagnetic shielding effect and enhancing the performance of the wireless charging device. By placing a connector on one side of the receiving coil, the wireless charging device can be better integrated with mobile phones, tablets, and other devices. This invention can continuously keep the wireless charging device in a stable high-current, full-load working state, effectively improving the efficiency of wireless charging and accelerating the charging speed of electronic products. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the front structure of a wireless charging device in the prior art;

[0025] Figure 2 This is a schematic diagram of the rear structure of a wireless charging device in the prior art;

[0026] Figure 3 This is a simulation diagram of the temperature rise during charging of a wireless charging device in the existing technology;

[0027] Figure 4 This is a front structural diagram of the wireless charging device for reducing eddy currents provided in this embodiment of the utility model;

[0028] Figure 5 This is a front structural schematic diagram of the wireless charging device (second soft magnet not shown) for reducing eddy currents provided in this embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the back structure of the wireless charging device (connector not shown) for reducing eddy currents provided in this embodiment of the present invention.

[0030] Figure 7 This is an exploded view of the wireless charging device for reducing eddy currents provided in this embodiment of the present invention;

[0031] Figure 8This is a schematic diagram of the structure of the receiving coil and flexible circuit board provided in this embodiment of the utility model;

[0032] Figure 9 This is a schematic diagram of the internal conductor circuit of the flexible circuit board provided in this embodiment of the utility model;

[0033] Figure 10 This is a simulation diagram of the temperature rise during charging of the wireless charging device for reducing eddy currents provided in this embodiment of the utility model.

[0034] In the picture:

[0035] 1' Soft magnet; 2' Receiving coil; 3' Flexible circuit board;

[0036] 1. First soft magnet; 11. First through hole; 12. Second through hole;

[0037] 2. Receiving coil; 21. First connection terminal; 22. Second connection terminal;

[0038] 3. Flexible circuit board; 31. Inner conductor circuit; 311. Sub-circuit; 32. Outer conductor circuit;

[0039] 4. Second soft magnet;

[0040] 5. Connectors. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0042] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this utility model, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are merely used for distinction in description and have no special meaning.

[0045] like Figures 1-3 As shown, existing wireless charging devices include a soft magnet 1', a receiving coil 2', and a flexible circuit board 3'. The lines of both the receiving coil 2' and the flexible circuit board 3' are located on the same side of the soft magnet 1'. This structure easily generates eddy currents in the flexible circuit board 3', leading to high heat generation in the wireless charging device and excessive temperature rise in electronic products. While limiting the charging current can reduce overheating, it can also result in lower charging efficiency for electronic products.

[0046] To address the aforementioned issues, this embodiment provides a wireless charging device that reduces eddy currents. As the receiver of a wireless charging system, it can be applied to electronic products such as mobile phones, tablets, laptops, smartwatches, and smart glasses, thereby solving the problems of excessive temperature rise and slow charging speed of electronic products during wireless charging in the prior art.

[0047] like Figures 4 to 10As shown, the wireless charging device for reducing eddy currents provided in this embodiment includes a first soft magnet 1, a receiving coil 2, a flexible circuit board 3, a second soft magnet 4, and a connector 5. The first soft magnet 1 has an electromagnetic shielding function, and a first through hole 11 is formed on the first soft magnet 1, penetrating its upper and lower surfaces. Preferably, the first through hole 11 is located in the middle region of the first soft magnet 1. The receiving coil 2 is located below the first soft magnet 1. The receiving coil 2 is specifically a wound coil containing metal material, wound in a ring shape, including a first connecting end 21 wound on the inner side and a second connecting end 22 wound on the outer side. The first connecting end 21 is located below the first through hole 11, and the second connecting end 22 is located near the edge of the first soft magnet 1. The flexible circuit board 3 includes an inner conductor line 31 and an outer conductor line 32. The inner conductor line 31 is located above the first soft magnet 1, passes through the first through hole 11, and connects to the first connection terminal 21. The outer conductor line 32 is located below the first soft magnet 1 and connects to the second connection terminal 22, thus forming a closed circuit for charging electronic products. In this embodiment, the flexible circuit board 3 is a single-sided or double-sided FPC circuit board. The second soft magnet 4 is disposed above the first soft magnet 1 and covers the area above the connection between the inner conductor line 31 and the first connection terminal 21. The connector 5 is disposed on the side of the receiving coil 2 away from the first soft magnet 1 and is used to fix it to the electronic product.

[0048] The wireless charging device for reducing eddy currents provided in this embodiment places the inner conductor 31 and outer conductor 32 of the flexible circuit board 3 on the upper and lower sides of the first soft magnet 1, respectively. The inner conductor 31 is located above the first soft magnet 1, and the outer conductor 32 is located below the first soft magnet 1. The inner conductor 31 passes through the first through hole 11 and connects to the first connecting end 21, which is coiled inside the receiving coil 2 below the first soft magnet 1. The outer conductor 32 connects to the second connecting end 22, which is coiled outside the receiving coil 2. Since eddy currents are easily generated in the inner conductor 31 in the flexible circuit board 3, this embodiment uses the first soft magnet 1 to separate the inner conductor 31 from the receiving coil 2, thereby reducing the eddy currents formed by the magnetic field of the receiving coil 2 on the inner conductor 31. This effectively reduces the heat generation of the wireless charging device, reduces the temperature rise of electronic products, and improves the user experience and charging safety of electronic products. Furthermore, this embodiment can continuously maintain the wireless charging device in a stable high-current, full-load operating state, effectively improving the efficiency of wireless charging and accelerating the charging speed of electronic products. In addition, by setting a second soft magnet 4 above the inner conductor line 31, this embodiment can shield the leakage magnetic field of the receiving coil 2 at the first through hole 11, further improving the electromagnetic shielding effect and enhancing the performance of the wireless charging device; by setting a connector 5 on one side of the receiving coil 2, the wireless charging device can be better assembled with mobile phones, tablets, and other complete devices.

[0049] Optionally, a portion of the outer conductor line 32 is disposed directly below the first soft magnet 1 for connection to the second connection terminal 22 of the receiving coil 2, thereby preventing the second connection terminal 22 from protruding beyond the first soft magnet 1; another portion of the outer conductor line 32 protrudes laterally from the first soft magnet 1 for connection to the inner conductor line 31. Optionally, the portion of the outer conductor line 32 located directly below the first soft magnet 1 is in contact with the lower surface of the first soft magnet 1 to ensure the stability of the connection between the outer conductor line 32 and the first soft magnet 1.

[0050] Furthermore, a portion of the inner conductor line 31 is disposed directly above the first soft magnet 1 for connection to the first connection terminal 21 of the receiving coil 2; another portion of the inner conductor line 31 is laterally exposed above the first soft magnet 1, and the end of the inner conductor line 31 laterally exposed above the first soft magnet 1 is interconnected with the end of the outer conductor line 32 laterally exposed above the first soft magnet 1. Optionally, the portion of the inner conductor line 31 located directly above the first soft magnet 1 is in contact with the upper surface of the first soft magnet 1 to ensure the connection stability between the inner conductor line 31 and the first soft magnet 1.

[0051] In this embodiment, the coverage area of ​​the first soft magnet 1 is larger than that of the receiving coil 2, allowing the receiving coil 2 to be completely mounted on the first soft magnet 1, effectively providing electromagnetic shielding for the receiving coil 2. Furthermore, the coverage area of ​​the second soft magnet 4 is smaller than that of the receiving coil 2 but larger than the area of ​​the first through hole 11. In this embodiment, the size of the second soft magnet 4 only needs to be sufficient to cover the connection between the internal conductor 31 and the first connecting end 21, without needing to be excessively large to avoid material waste. Optionally, in this embodiment, the receiving coil 2 is annular, the first soft magnet 1 is a rectangular (i.e., one end of the rectangle is rounded) soft magnetic sheet, and the second soft magnet 4 is a circular soft magnetic sheet. Of course, in other embodiments, the shapes of the receiving coil 2, the first soft magnet 1, and the second soft magnet 4 can also be other shapes, and are not limited to this embodiment.

[0052] In this embodiment, the materials of the first soft magnet 1 and the second soft magnet 4 can be ferrite materials, ferrite amorphous materials, ferrite amorphous nanomaterials, or ferrite composite materials, etc. Preferably, the first soft magnet 1 and the second soft magnet 4 in this embodiment are both made of nanocrystalline materials or ferrite. Nanocrystalline materials have high saturation magnetic induction, high permeability, and low magnetic loss, while also being flexible and ultra-thin. Ferrite is prepared and sintered from ferric oxide and one or more other metal oxides (e.g., nickel oxide, zinc oxide, manganese oxide, magnesium oxide, barium oxide, strontium oxide, etc.), and can be mass-produced, has stable performance, and high machinability.

[0053] Optionally, in this embodiment, the inner conductor line 31 of the flexible circuit board 3 includes multiple strands of sub-lines 311 arranged in parallel. Since the area with the strongest magnetic field (i.e., the area most prone to eddy current formation) in the flexible circuit board 3 is the inner conductor line 31, this embodiment subdivides the inner conductor line 31 into multiple strands of sub-lines 311, which can further reduce eddy currents in the circuit. Specifically, the inner conductor line 31 in this embodiment can be Litz wire or self-adhesive enameled wire. It should be noted that the above-mentioned Litz wire refers to a conductor made of multiple independently insulated conductors twisted or braided; the above-mentioned self-adhesive enameled wire refers to a conductor in which the coils are bonded together under appropriate solvent or heating conditions. Exemplarily, the inner conductor line 31 in this embodiment is a flat conductor with a certain width. The flat conductor is divided into multiple parallel and spaced sub-lines 311 in the area directly above the first soft magnet 1. Its structure is simple, easy to process, and has stable performance.

[0054] In this embodiment, the connector 5 is made of colloid or Mylar. Further, the connector 5 is sheet-shaped, with the same shape as the first soft magnet 1, to achieve a better connection effect. In this embodiment, when the connector 5 is made of colloid, the colloid can be hot melt adhesive or pressure-sensitive adhesive, and can be double-sided or single-sided adhesive; when the connector 5 is made of Mylar, a second through hole 12 penetrating the upper and lower surfaces of the first soft magnet 1 can be formed, and connection holes are also provided on the Mylar, thereby achieving the fastening of the wireless charging device and the electronic product through fastening screws.

[0055] In this embodiment, the first connection end 21 of the receiving coil 2 is connected to the inner conductor line 31 of the flexible circuit board 3 by welding, and the second connection end 22 of the receiving coil 2 is connected to the outer conductor line 32 of the flexible circuit board 3 by welding. After the receiving coil 2 and the flexible circuit board 3 form a circuit, they can be connected to electronic products such as mobile phones or tablets to charge the electronic products. Optionally, the receiving coil 2 and the first soft magnet 1, the first soft magnet 1 and the flexible circuit board 3, and the second soft magnet 4 and the first soft magnet 1 are all fixed by adhesive bonding. For example, they can be bonded with single-sided adhesive or double-sided adhesive. The above connection method is convenient to operate and flexible to assemble.

[0056] Optionally, the wireless charging device in this embodiment further includes a heat dissipation component for dissipating heat from the receiving coil 2, thereby further reducing the temperature rise of the electronic product. Specifically, the heat dissipation component can be a graphite heat sink or a silicone heat sink, and the heat dissipation component is bonded and fixed to the first soft magnet 1 or the connector 5 to improve the heat dissipation capacity of the electronic product.

[0057] Optionally, the wireless charging device in this embodiment further includes a rigid protective film component, which is disposed on the outside of the first soft magnet 1 to increase the rigidity of the wireless charging device and improve its structural strength. Further, the wireless charging device also includes a reinforcing component, which is fixed to the first soft magnet 1 or the receiving coil 2. Specifically, the reinforcing component can be a reinforcing plate, and the material of the reinforcing plate can be plastic or metal. By setting the reinforcing component, the wireless charging device can have higher strength, is less prone to deformation, and better match electronic products.

[0058] Figure 3 A simulation diagram of temperature rise during charging of a wireless charging device in the prior art. Figure 10 A simulation diagram of the temperature rise during charging of the wireless charging device with reduced eddy currents provided in this embodiment. Figure 3 and Figure 10 The comparison shows that, compared with traditional wireless charging devices, the wireless charging device with reduced eddy currents provided in this embodiment reduces the eddy currents formed by the magnetic field of the receiving coil 2 on the inner conductor line 31 because the inner conductor line 31 is on the upper side of the first soft magnet 1. Therefore, it generates less heat, has a more uniform temperature, and does not have concentrated hot spots, resulting in a significant temperature improvement effect.

[0059] Furthermore, as shown in the table below, a comparison of temperature rise data of the prior art and the wireless charging receiver provided in this improved embodiment is presented.

[0060] state Inductance (L) 100kHz = Resistance (R) Q-Factor phase Current (A) B (Tesla) Max: Efficiency_% Max: Temperature rise Before improvement 8.2uH 281mohm 18.38 0 2 0.0395 81％ 58° After improvement 8.2uH 281mohm 18.38 0 2 0.0056 83％ 51°

[0061] This comparative experiment was conducted at a frequency of 100kHz, with the same inductance L, resistance R, and Q values. Inductance L represents the receiving coil's ability to store magnetic field energy; its value indicates the coil's size or the number of coils. Resistance R represents the internal resistance of the coil's conductors. Q is the quality factor, representing the coil's performance at its operating frequency; specifically, Q is the ratio of the coil's self-inductance L to its resistance R, i.e., Q = ωL / R, where ω is the angular frequency (2π multiplied by the frequency). The table clearly shows that, under the same conditions, the improved solution in this embodiment effectively reduces the magnetic flux density B (Tesla) in the internal conductors during wireless charging, lowers temperature rise, improves charging efficiency, and simultaneously ensures device safety and lifespan compared to existing solutions.

[0062] This embodiment also provides an electronic product, including a housing, a battery, and the aforementioned eddy current-reducing wireless charging device. Both the battery and the wireless charging device are installed within the housing, and the wireless charging device is used to charge the battery. When the electronic product provided in this embodiment is near a charging base, its charging process is as follows: An alternating current is passed through the transmitting coil in the charging base, generating a continuously changing magnetic field. The receiving coil 2 senses the changing magnetic field generated by the transmitting coil and generates an induced current. This induced current, after further processing, charges the battery. This embodiment reduces the eddy currents formed by the magnetic field of the receiving coil 2 on the inner conductor line 31, reducing the heat generated by the wireless charging device and lowering the temperature rise of the electronic product; at the same time, it improves the efficiency of wireless charging and accelerates the charging speed of the electronic product.

[0063] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A wireless charging device for reducing eddy currents, characterized in that, include: A first soft magnet (1) is provided with a first through hole (11) penetrating its upper and lower surfaces; A receiving coil (2) is disposed below the first soft magnet (1). The receiving coil (2) includes a first connecting end (21) coiled on the inner side and a second connecting end (22) coiled on the outer side. The first connecting end (21) is located below the first through hole (11), and the second connecting end (22) is close to the edge of the first soft magnet (1). The flexible circuit board (3) includes an inner conductor line (31) and an outer conductor line (32). The inner conductor line (31) is located above the first soft magnet (1) and connected to the first connection end (21) after passing through the first through hole (11). The outer conductor line (32) is located below the first soft magnet (1) and connected to the second connection end (22). The second soft magnet (4) is disposed above the first soft magnet (1) and covers the position above the connection between the inner conductor line (31) and the first connection end (21); A connector (5) is disposed on the side of the receiving coil (2) away from the first soft magnet (1) for fixing to the electronic product.

2. The wireless charging device for reducing eddy currents according to claim 1, characterized in that, The coverage area of ​​the first soft magnet (1) is greater than the coverage area of ​​the receiving coil (2), and the coverage area of ​​the second soft magnet (4) is smaller than the coverage area of ​​the receiving coil (2).

3. The wireless charging device for reducing eddy currents according to claim 1, characterized in that, The internal conductor lines (31) of the flexible circuit board (3) include multiple sub-lines (311) arranged in parallel.

4. The wireless charging device for reducing eddy currents according to claim 3, characterized in that, The internal conductor lines (31) of the flexible circuit board (3) are Litz wire or self-adhesive enameled wire.

5. The wireless charging device for reducing eddy currents according to claim 1, characterized in that, The connector (5) is a colloid or Mylar.

6. The wireless charging device for reducing eddy currents according to claim 5, characterized in that, The connector (5) is sheet-shaped, and the shape of the connector (5) is the same as that of the first soft magnet (1).

7. The wireless charging device for reducing eddy currents according to claim 5, characterized in that, The first soft magnet (1) has a second through hole (12) extending through its upper and lower surfaces for fixing to electronic products by fasteners.

8. The wireless charging device for reducing eddy currents according to claim 1, characterized in that, The receiving coil (2) is fixed to the first soft magnet (1), the first soft magnet (1) is fixed to the flexible circuit board (3), and the second soft magnet (4) is fixed to the first soft magnet (1) by adhesive bonding.

9. The wireless charging device for reducing eddy currents according to claim 1, characterized in that, Both the first soft magnet (1) and the second soft magnet (4) are made of nanocrystalline materials or ferrite.

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