Magnetic shielding structure and manufacturing method thereof, wireless charging system

Abstract

The present application discloses a magnetic shielding structure, a manufacturing method thereof, and a wireless charging system, the magnetic shielding structure comprising a magnetic shielding plate, a ferrite layer, and a nanocrystalline layer, the ferrite layer comprising a plurality of ferrite sheets laid flat on the magnetic shielding plate, the nanocrystalline layer laid flat on the ferrite layer, the nanocrystalline layer comprising a plurality of stacked nanocrystalline strips and an insulating tape positioned between two adjacent nanocrystalline strips, the insulating tape being configured to bond the two adjacent nanocrystalline strips, the nanocrystalline layer having a plurality of through holes penetrating the nanocrystalline layer along the stacking direction, the plurality of through holes being uniformly spaced apart.

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application bearing application number 202211570225.1, filed with the China Patent Office on December 8, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of wireless charging, for example, to a magnetic shielding structure and a manufacturing method thereof, and a wireless charging system. [Background technology]

[0003] Wireless charging technology can achieve electrical isolation between the power source and the load, and is characterized by its convenience, flexibility, safety and reliability. Wireless charging technology has been applied to consumer electronic products and is gradually expanding its application to fields such as electric vehicles, smart homes and robots.

[0004] In related art, the magnetic flux guide structure of a wireless charging system is mainly made of rectangular soft magnetic ferrite material. The magnetic flux guide body made of soft magnetic ferrite has high resistivity and can suppress eddy currents, allowing the magnetic flux guide structure to be used in high-frequency ranges. It also has stable chemical properties and can be customized in shape and size. However, a drawback of soft magnetic ferrite magnetic flux guide structures is their low saturation magnetic flux density, which directly leads to large volume and weight of the electrical energy coupling mechanism in high-power wireless charging systems, making the entire device using the wireless charging system very heavy. Related art has proposed a solution to replace soft magnetic ferrite with nanocrystals. While nanocrystals are effective in low-power applications such as mobile phones, in high-power applications such as electric vehicles, the magnetic field strength in the wireless charging system is higher than in low-power applications, resulting in increased loss of the nanocrystalline strip material and heat generation, which affects the energy transmission efficiency of the wireless charging system. Summary of the Invention

[0005] The present application provides a magnetic shielding structure and manufacturing method thereof, as well as a wireless charging system, which can mitigate the heat generation during charging and have high electrical energy transmission efficiency.

[0006] This application is A magnetic shield plate; a ferrite layer including a plurality of ferrite sheets laid flat on the magnetic shield plate; a nanocrystalline layer including a plurality of nanocrystalline strips laid flat on the ferrite layer and stacked thereon, and an insulating tape positioned between two adjacent nanocrystalline strips and configured to bond the two adjacent nanocrystalline strips together; The nanocrystalline layer has a plurality of uniformly spaced through-holes extending through the nanocrystalline layer along the stacking direction, providing a magnetic shielding structure.

[0007] This application is sequentially attaching the plurality of nanocrystalline strips together with insulating tape to form a multi-layered nanocrystalline structure; punching the nanocrystalline structure; performing a cutting process on the nanocrystalline structure after the punching process to obtain a nanocrystalline layer; cutting a whole piece of ferrite into a plurality of ferrite sheets; laying the plurality of ferrite sheets flat on a magnetic shield plate to form a ferrite layer; and laying the nanocrystalline layer flat on a surface of the ferrite layer away from the magnetic shield plate to obtain a magnetic shielding structure.

[0008] The present application further provides a wireless charging system including the above magnetic shielding structure. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a layer structure of a magnetic shielding structure according to Example 1 of the present application. [Figure 2] FIG. 2 is a schematic diagram of a nanocrystalline layer stack according to Example 1 of the present application. [Figure 3] FIG. 2 is a plan view of a nanocrystalline layer according to Example 1 of the present application. [Figure 4] 10 is a flowchart of a method for manufacturing a magnetic shielding structure according to a second embodiment of the present invention.

[0010] 1···Magnetic shield plate, 2···Ferrite layer, 21···Ferrite sheet, 3···Nanocrystalline layer, 31···Nanocrystalline strip material, 32···Insulating tape, 33···Through hole. DETAILED DESCRIPTION OF THE INVENTION

[0011] The technical solution of the present application will be described below by specific embodiments with reference to the drawings. The specific examples described here are only for the purpose of interpreting the present application and are not intended to limit the present application. For ease of explanation, the drawings only show parts relevant to the present application, not all of the parts.

[0012] In the description of this application, unless otherwise clearly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense, and may mean, for example, a fixed connection, a detachable connection, or integration, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, internal communication between two elements, or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0013] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include direct contact between the first and second features, or may include contact between the first and second features through another feature between them, rather than direct contact. Furthermore, a first feature being "above," "above," and "on the upper surface" of a second feature may include the first feature being directly above and diagonally above the second feature, or may simply indicate that the horizontal height of the first feature is higher than that of the second feature. A first feature being "below," "below," and "on the lower surface" of a second feature may include the first feature being directly below and diagonally below the second feature, or may simply indicate that the horizontal height of the first feature is smaller than that of the second feature.

[0014] In the description of the present embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are merely used to facilitate the description and simplify the operation. They do not indicate or imply that such devices or elements must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be understood as limiting the present application. Furthermore, the terms "first" and "second" are merely used to distinguish between the above and the following in the description, and do not have any special meaning.

[0015] Example 1 This embodiment provides a magnetic shielding structure that can alleviate the heat generation during charging and has high electrical energy transmission efficiency.

[0016] As shown in FIG. 1, the magnetic shielding structure includes a magnetic shield plate 1, a ferrite layer 2, and a nanocrystalline layer 3, which are stacked one on top of the other.

[0017] The magnetic shield plate 1 may be a plate-like structure provided on the coil side of the wireless charging system, and is configured to support the ferrite layer 2 and the nanocrystalline layer 3. The magnetic shield plate 1 is an insulating plate.

[0018] The ferrite layer 2 includes a plurality of ferrite sheets 21, which are arranged so as to be in contact with one another or spaced apart from one another. The plurality of ferrite sheets 21 are laid flat on the magnetic shield plate 1, and in some embodiments, the plurality of ferrite sheets 21 are arranged in an array on the top surface of the magnetic shield plate 1. To improve the integrity of the plurality of ferrite sheets 21, the plurality of ferrite sheets 21 may be bonded together, for example, by an adhesive film.

[0019] The nanocrystalline layer 3 is laid flat on the ferrite layer 2, i.e., the nanocrystalline layer 3 is located on the surface of the ferrite layer 2 that is away from the magnetic shield plate 1. The nanocrystalline layer 3 comprises multiple layers of nanocrystalline strips 31 stacked together, with insulating tape 32 positioned between two adjacent layers of the nanocrystalline strips 31. The two adjacent layers of nanocrystalline strips 31 are bonded together by the insulating tape 32, and the nanocrystalline layer 3 has multiple through-holes 33 that penetrate the nanocrystalline layer 3 along the stacking direction of the multiple layers of nanocrystalline strips 31, and the multiple through-holes 33 are uniformly spaced apart. In some embodiments, the through-holes 33 are formed by pressing. In this embodiment, the nanocrystalline layer 3 can be bonded to the ferrite layer 2 by an adhesive layer, which makes the magnetic shielding structure an integrated structure and facilitates subsequent assembly.

[0020] In the magnetic shielding structure of this embodiment, the nanocrystalline layer 3 comprises multiple layers of nanocrystalline strip material 31, and the nanocrystalline layer 3 has multiple through holes 33. The through holes 33 divide each layer of nanocrystalline strip material 31 into different regions, destroying the integrity of the multiple layers of nanocrystalline strip material 31 and reducing eddy current loss on the surface of the multiple layers of nanocrystalline strip material 31. Furthermore, when the magnetic shielding structure is applied to high-power equipment, the heat generation that occurs during charging can be alleviated. Furthermore, the use of the high-permeability ferrite sheet 21 combined with the low-permeability nanocrystalline layer 3 allows the magnetic field lines to pass through the magnetic shielding plate 1 from bottom to top, and can better concentrate the magnetic field lines and reduce the magnetic flux leakage phenomenon. This allows the magnetic shielding structure to have high electrical energy transmission efficiency, i.e., good charging efficiency.

[0021] Preferably, the through-holes 33 are round, polygonal, or fan-shaped, but this embodiment is not limited thereto. Exemplarily, the through-holes 33 are round, and the diameter of the through-holes 33 is in the range of 3 to 6 mm. Preferably, the diameter of the through-holes 33 is 4 mm. In some embodiments, the through-holes 33 are arranged in an array along the length and width directions of the nanocrystalline layer 3, as shown in FIG. 3 .

[0022] In this embodiment, the number of layers of the nanocrystalline strip 31 is in the range of 12 to 90. The specific number of layers of the nanocrystalline strip 31 can be set according to needs, and the thickness of each layer of the nanocrystalline strip 31 is in the range of 0.28 to 3 millimeters. The magnetic permeability of the nanocrystalline strip 31 is in the range of 200 to 2000 Henry / meter (H / m). For example, the magnetic permeability of the nanocrystalline strip 31 is 700 H / m.

[0023] Preferably, the ferrite sheet 21 in this embodiment is square in shape to have good magnetic permeability. The length of each side of the ferrite sheet 21 is within a range of 50 to 100 mm. For example, the length of each side of the ferrite sheet 21 is 100 mm. The thickness of the ferrite sheet 21 is within a range of 1 to 3 mm, and preferably, the thickness of the ferrite sheet 21 is 2 mm. The magnetic permeability of the ferrite sheet 21 is within a range of 2000 to 4000 H / m. Preferably, the magnetic permeability of the ferrite sheet 21 is 3300 H / m.

[0024] Preferably, the top surface of the magnetic shielding plate 1 has a plurality of partition bars, which are connected vertically and horizontally to form a plurality of mounting grooves, and each ferrite sheet 21 is mounted in one of the mounting grooves, thereby preventing collisions between two adjacent ferrite sheets 21 and improving the reliability of the magnetic shielding structure.

[0025] The magnetic shielding structure according to this embodiment solves the problem of high power loss and heat generation, and improves the charging efficiency of wireless charging.

[0026] The following three examples are presented as examples to demonstrate the performance of the magnetic shielding structure of the present application, a magnetic flux guide structure formed solely of ferrite, and a magnetic flux guide structure formed solely of nanocrystals.

[0027] [Table 1] The 3-layer MS700 Nanocrystalline is a nanocrystalline magnetic shielding sheet with a magnetic permeability of 700.

[0028] [Table 2]

[0029] In Example 1, a nanocrystalline strip 31 is laminated with insulating tape 32 and then compositely bonded to form 72 nanocrystalline layers 3 of the nanocrystalline strip 31. The nanocrystalline layers 3 are then cut to form nanocrystalline layers 3 measuring 400 mm x 60 mm x 2.4 mm. The nanocrystalline layers 3 are then punched to form through-holes 33 with a diameter of 4 mm, 14 holes per row, and 95 holes per column, with all holes evenly distributed across the surface of the nanocrystalline layer 3. The magnetic permeability of the nanocrystalline layer 3 after processing is 700 H / m. A single ferrite sheet is then cut to form a ferrite sheet 21 measuring 100 mm x 100 mm x 2 mm, with the magnetic permeability of the selected ferrite sheet 21 being 3300 H / m. The charging efficiency and heat generation status of the magnetic shielding structures having the above sizes were tested, as well as the charging efficiency and heat generation status of PC95 ferrite and three-layer MS700 nanocrystal, and the results are shown in Table 2. As can be seen from Table 2, the magnetic shielding structure of this example has the highest initial system efficiency among the three, the initial magnetic sheet surface temperature is the same as that of the three-layer MS700 nanocrystal, and the system efficiency at the end of operation is also the highest, with the magnetic sheet surface temperature at the end of operation being slightly higher than that of PC95 ferrite but much lower than that of the three-layer MS700 nanocrystal.

[0030] In Example 2, a nanocrystalline strip 31 is laminated with insulating tape 32 and then compositely bonded to form 72 nanocrystalline layers 3 of the nanocrystalline strip 31. The nanocrystalline layers 3 are then cut to form nanocrystalline layers 3 measuring 400 mm x 60 mm x 2.4 mm. The nanocrystalline layers 3 are then punched to form through-holes 33 with a diameter of 6 mm, 11 holes per row, and 75 holes per column, with all holes evenly distributed across the surface of the nanocrystalline layer 3. The magnetic permeability of the nanocrystalline layer 3 after processing is 200 H / m. A single ferrite sheet is then cut to form a ferrite sheet 21 measuring 50 mm x 50 mm x 1 mm, with the magnetic permeability of the selected ferrite sheet 21 being 2000 H / m. The charging efficiency and heat generation status of the magnetic shielding structures having the above sizes were tested, as were the charging efficiency and heat generation status of PC95 ferrite and three-layer MS700 nanocrystalline, and the results are shown in Table 4. As can be seen from Table 4, the magnetic shielding structure of this example has the highest initial system efficiency among the three, the initial magnetic sheet surface temperature is the same as that of three-layer MS700 nanocrystalline, the system efficiency at the end of operation is slightly lower than that of PC95 ferrite but much higher than that of three-layer MS700 nanocrystalline, and the magnetic sheet surface temperature at the end of operation is slightly higher than that of PC95 ferrite but much lower than that of three-layer MS700 nanocrystalline.

[0031] [Table 3]

[0032] [Table 4]

[0033] In example 3, a nanocrystalline strip 31 is laminated with insulating tape 32 and then compositely bonded to form 72 nanocrystalline layers 3 of the nanocrystalline strip 31. The nanocrystalline layers 3 are then cut to form nanocrystalline layers 3 measuring 400 mm x 60 mm x 2.4 mm. The nanocrystalline layers 3 are then punched to form through-holes 33 with a diameter of 3 mm. The nanocrystalline layer 3 has 16 holes per row and 110 holes per column, resulting in 126 holes evenly distributed across the surface of the nanocrystalline layer 3. The magnetic permeability of the nanocrystalline layer 3 after processing is 700 H / m. A single ferrite magnetic sheet is then cut to form a ferrite sheet 21 measuring 100 mm x 100 mm x 3 mm. The magnetic permeability of the selected ferrite sheet 21 is 4000 H / m. The charging efficiency and heat generation status of the magnetic shielding structures having the above sizes were tested, as were the charging efficiency and heat generation status of the PC95 ferrite and the three-layer MS700 nanocrystal, and the results are shown in Table 6. As can be seen from Table 6, the magnetic shielding structure of this example has the highest initial system efficiency of the three, the initial magnetic sheet surface temperature is the same as that of the three-layer MS700 nanocrystal, and the system efficiency at the end of operation is the highest of the three, and the magnetic sheet surface temperature at the end of operation is slightly higher than that of the PC95 ferrite but much lower than that of the three-layer MS700 nanocrystal.

[0034] [Table 5]

[0035] [Table 6]

[0036] Example 2 This embodiment provides a method for manufacturing the magnetic shielding structure in the first embodiment. As shown in FIG. 4, the method for manufacturing the magnetic shielding structure includes the following steps:

[0037] S1: A plurality of nanocrystalline strips 31 are sequentially bonded together with insulating tape 32 to form a multi-layered nanocrystalline structure. In step S1, insulating tape 32 is attached to the first and second surfaces of individual nanocrystalline strips 31, and then the single nanocrystalline strips are laminated together to form a multilayer structure.

[0038] S2, punching process is performed on the nanocrystalline structure. In step S2, the nanocrystalline structure obtained in step S1 is subjected to a punching process so that through-holes 33 are punched evenly distributed on the surface of the nanocrystalline structure.

[0039] S3: The nanocrystalline structure after punching is cut to obtain a nanocrystalline layer 3. The nanocrystalline structure with through holes 33 is cut to obtain the required size.

[0040] S4: Cut the entire ferrite into a plurality of ferrite sheets 21. In step S4, the entire ferrite sheet is cut into a plurality of squares of appropriate size.

[0041] S5: A plurality of ferrite sheets 21 are laid flat on the magnetic shield plate 1 to form the ferrite layer 2.

[0042] S6: A nanocrystalline layer 3 is laid flat on the surface of the ferrite layer 2 away from the magnetic shield plate 1 to obtain a magnetic shielding structure.

[0043] In the manufacturing method of the magnetic shielding structure of this embodiment, the nanocrystalline layer 3 and the ferrite layer 2 are first prepared, and then the nanocrystalline layer 3 and the ferrite layer 2 are laid flat on the magnetic shielding plate 1. The nanocrystalline layer 3 comprises multiple layers of nanocrystalline strip material 31, and the nanocrystalline layer 3 has multiple through holes 33. The through holes 33 divide each layer of nanocrystalline strip material 31 into different regions, destroying the integrity of the multiple layers of nanocrystalline strip material 31 and reducing eddy current loss on the surface of the multiple layers of nanocrystalline strip material 31. Furthermore, when the magnetic shielding structure is applied to high-power equipment, the heat generation that occurs during charging can be alleviated. Furthermore, the use of the high-permeability ferrite sheet 21 combined with the low-permeability nanocrystalline layer 3 allows the magnetic field lines to pass through the magnetic shielding plate 1 from bottom to top more efficiently and better gather the magnetic field lines, thereby reducing the magnetic flux leakage phenomenon. This allows the magnetic shielding structure to have high electrical energy transmission efficiency, that is, good charging efficiency.

[0044] Example 3 This embodiment provides a wireless charging system equipped with the magnetic shielding structure of embodiment 1. The wireless charging system of this embodiment has a good charging effect and can further reduce the heat generation during the charging process when applied to high-power equipment.

Claims

1. A magnetic shield plate (1), a ferrite layer (2) comprising a plurality of ferrite sheets (21) laid flat on the magnetic shield plate (1); a nanocrystalline layer (3) including a plurality of nanocrystalline strips (31) laid flat on the ferrite layer (2) and stacked on top of each other, and an insulating tape (32) positioned between two adjacent nanocrystalline strips (31) and configured to bond the two adjacent nanocrystalline strips (31); The nanocrystalline layer (3) has a plurality of through holes (33) that penetrate the nanocrystalline layer (3) along the stacking direction and are uniformly distributed at intervals. Magnetic shielding structure.

2. Each through hole (33) is a round hole, a polygonal hole or a sector hole; The magnetic shielding structure according to claim 1 .

3. Each through hole (33) is a round hole and has a diameter in the range of 3 to 6 millimeters. The magnetic shielding structure according to claim 2 .

4. The number of layers of the nanocrystalline strip material (31) is in the range of 12 to 90, and the thickness of each layer of the nanocrystalline strip material (31) is in the range of 0.28 to 3 millimeters. The magnetic shielding structure according to claim 1 .

5. Each ferrite sheet (21) is square, with a side length in the range of 50 to 100 mm and a thickness in the range of 1 to 3 mm; The magnetic shielding structure according to claim 1 .

6. The magnetic permeability of the nanocrystalline strip (31) is in the range of 200 to 2000 Henry / meter, and the magnetic permeability of the ferrite sheet (21) is in the range of 2000 to 4000 Henry / meter. The magnetic shielding structure according to claim 1 .

7. The top surface of the magnetic shield plate (1) has a plurality of partition bars connected vertically and horizontally to form a plurality of mounting grooves, and each ferrite sheet (21) is mounted corresponding to one of the mounting grooves. The magnetic shielding structure according to claim 1 .

8. The plurality of through holes (33) are arranged in an array. The magnetic shielding structure according to claim 1 .

9. A plurality of nanocrystalline strips (31) are successively bonded together with insulating tape (32) to form a nanocrystalline structure having a multi-layer structure; performing a punching process on the nanocrystalline structure; performing a cutting process on the nanocrystalline structure after the punching process to obtain a nanocrystalline layer (3); Cutting a whole piece of ferrite into a plurality of ferrite sheets (21); laying the plurality of ferrite sheets (21) flat on a magnetic shield plate (1) to form a ferrite layer (2); and laying the nanocrystalline layer (3) flat on a surface of the ferrite layer (2) that faces away from the magnetic shield plate (1) to obtain a magnetic shielding structure. A method for manufacturing the magnetic shielding structure according to any one of claims 1 to 8.

10. A magnetic shielding structure according to any one of claims 1 to 8, Wireless charging system.

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