A shielding sheet for a wireless charging module and a wireless charging module

Abstract

The application discloses a shielding sheet for a wireless charging module and the wireless charging module. The shielding sheet for the wireless charging module comprises an outer magnetic sheet and a center magnetic sheet. The outer magnetic sheet is provided with a through hole, and the center magnetic sheet is arranged in the through hole. A gap is formed between the peripheral wall of the center magnetic sheet and the wall surface of the through hole. The outer magnetic sheet comprises at least one first magnetic conductive layer, and the first magnetic conductive layer is nanocrystalline strip material, amorphous strip material or metal soft magnetic strip material. The center magnetic sheet comprises at least one second magnetic conductive layer, and the second magnetic conductive layer is nanocrystalline strip material, amorphous strip material or metal soft magnetic strip material. Compared with the traditional magnetic shielding sheet and the charging module, the shielding sheet for the wireless charging module and the wireless charging module provided by the application have improved charging efficiency and saturation current under the condition of the same shielding performance. In addition, the traditional 'broken magnetic' process is not needed in the production process of the shielding sheet, which is beneficial to reducing the process of the shielding sheet and lowering the manufacturing cost of the shielding sheet.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding structure technology, and in particular to a shielding sheet for a wireless charging module and a wireless charging module. Background Technology

[0002] Wireless charging technology, also known as inductive charging or contactless charging, utilizes near-field induction, or inductive coupling, to transfer energy from the power supply device (the transmitter) to the power consumption device (the receiver). The main characteristic of wireless charging technology is the near-distance inductive coupling of the non-contact coupling transformer, similar to a conventional resonant switching power supply.

[0003] Existing wireless charging products incorporate magnetic shielding sheets, which are magnetic materials, typically thin-layered ferrite, amorphous ribbons, or nanocrystalline ribbons. These ribbons generally possess high permeability, with single-layer thicknesses ranging from 10µm to 30µm. They are typically laminated and stacked to create a multi-layered structure, thereby increasing the overall inductance of the material. The presence of this magnetic shielding sheet provides a low-impedance path for magnetic field lines, isolating outward-dissipating magnetic energy. This prevents the magnetic field from penetrating the magnetic material and reaching the interior of the electronic device, thus avoiding energy loss due to magnetic field absorption by internal components such as metals (batteries). This helps reduce electromagnetic interference and improve magnetoelectric conversion efficiency. The magnetic focusing effect of the shielding material effectively reduces the number of turns in the charging coil, thereby reducing eddy current losses. Therefore, the magnetic shielding material needs to possess high saturation magnetic induction, permeability, and low loss.

[0004] With the rapid development of the electronics and information industry, increasingly higher demands are being placed on wireless charging technology. High power and high efficiency have become the future development trends for wireless charging. Traditional wireless charging magnetic shielding sheet manufacturing processes involve fragmenting the magnetic sheet (i.e., magnetic strip) to reduce eddy current losses. For example, Chinese invention patent application number 201280062847.1 describes mechanically crushing the magnetic sheet to create fragmented magnetic conductive sheets. This technology has risks such as high manufacturing costs and the risk of exposed fragments causing pollution. Furthermore, the fragmentation of the magnetic sheet significantly reduces its permeability, requiring multiple layers to meet the high permeability channels needed for high-efficiency charging and reduce the risk of magnetic leakage. However, with the trend towards miniaturization and thinner designs in mobile terminal products such as smartphones, watches, and headphones, new demands for thinner and lighter magnetic shielding sheets for wireless charging have emerged. While the traditional multi-layered, fragmented magnetic shielding sheet structure can provide strong magnetic focusing, its thickness and cost make it less suitable for meeting the demands for thinner and lower-cost designs. Therefore, the numerous problems inherent in traditional wireless charging, such as low charging efficiency, high cost, complex manufacturing processes, and low yield rates, are significant factors hindering its development. How to minimize the thickness of wireless charging modules while ensuring charging efficiency, and thereby reduce their production costs, is a pressing issue that needs to be addressed in the development of wireless charging modules. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a shielding sheet for a low-cost wireless charging module with high charging efficiency and a wireless charging module.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a shielding sheet for a wireless charging module, comprising an outer magnetic sheet and a central magnetic sheet, wherein the outer magnetic sheet has a through hole, the central magnetic sheet is disposed in the through hole, and there is a gap between the peripheral wall of the central magnetic sheet and the wall surface of the through hole; the outer magnetic sheet comprises at least one first magnetic conductive layer, wherein the first magnetic conductive layer is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape; the central magnetic sheet comprises at least one second magnetic conductive layer, wherein the second magnetic conductive layer is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape.

[0007] To solve the above-mentioned technical problems, the present invention also adopts the following technical solution: a wireless charging module, including a charging coil, and a shielding sheet for the wireless charging module, wherein the central magnetic sheet is disposed corresponding to the hollow area of ​​the charging coil.

[0008] Furthermore, the inner edge surface of the charging coil is coplanar with the peripheral wall of the central magnetic sheet.

[0009] The beneficial effects of this invention are as follows: Since the outer magnetic sheet is perpendicular to the direction of the induced eddy current, when the outer magnetic sheet has multiple layers of first magnetic conductive layers, there is insulating glue between the stacked first magnetic conductive layers. Therefore, no matter how high the magnetic loss μ" of the outer magnetic sheet is, it will not generate long free-path eddy currents (when the outer magnetic sheet has only one layer of first magnetic conductive layer, the thickness of a single first magnetic conductive layer is relatively thin (thickness ≤30μm), and long free-path eddy currents will also not be generated). Therefore, the outer magnetic sheet maintains both ultra-high magnetic permeability and low eddy current loss; in addition, although the magnetic field generates eddy currents in the central magnetic sheet... While the central magnetic sheet is within the magnetic sheet surface, it is isolated from the outer magnetic sheet by a gap, thus preventing long-free-path eddy currents from appearing on the central magnetic sheet. Simulation results show that, compared to traditional shielding sheets, this shielding sheet requires fewer layers of outer and central magnetic sheets to achieve the same shielding performance. This facilitates miniaturization and thinning of the shielding sheet, while also improving module charging efficiency and saturation current. Furthermore, it eliminates the need for additional "air gaps" or "insulation cracks" in the material, shortening the manufacturing process, improving product yield, and reducing the production cost of wireless charging modules. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view of the wireless charging module according to Embodiment 1 of the present invention;

[0011] Figure 2 This is a schematic diagram illustrating the working principle of the wireless charging module according to Embodiment 1 of the present invention.

[0012] Figure 3 This is a top view of the wireless charging module according to Embodiment 1 of the present invention (after hiding the first adhesive layer);

[0013] Figure 4 This is a top view of the wireless charging module according to Embodiment 2 of the present invention (after hiding the first adhesive layer);

[0014] Figure 5 This is a top view of a wireless charging module with another structure according to Embodiment 2 of the present invention (after hiding the first adhesive layer);

[0015] Figure 6 This is a top view of a wireless charging module with another structure according to Embodiment 2 of the present invention (after hiding the first adhesive layer);

[0016] Figure 7 This is a top view of a wireless charging module with another structure according to Embodiment 2 of the present invention (after hiding the first adhesive layer);

[0017] Figure 8 This is a top view of a wireless charging module with another structure according to Embodiment 2 of the present invention (after hiding the first adhesive layer);

[0018] Figure 9This is a top view of the wireless charging module according to Embodiment 3 of the present invention (after hiding the first adhesive layer);

[0019] Figure 10 This is a top view of a wireless charging module with another structure according to Embodiment 3 of the present invention (after hiding the first adhesive layer);

[0020] Figure 11 This is a top view of the wireless charging module according to Embodiment 4 of the present invention (after hiding the first adhesive layer);

[0021] Figure 12 This is a top view of the wireless charging module according to Embodiment 5 of the present invention (after hiding the first adhesive layer).

[0022] Label Explanation:

[0023] 1. Charging coil; 2. Outer magnetic sheet; 3. Central magnetic sheet; 4. Through hole; 5. Gap; 6. First magnetic conductive layer; 7. Second magnetic conductive layer; 8. First cut pattern; 9. Insulating adhesive layer; 10. Inner edge surface; 11. First adhesive layer; 12. Second adhesive layer; 13. Third adhesive layer; 14. Second cut pattern. Detailed Implementation

[0024] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0025] Nanocrystalline ribbons are nanocrystalline soft magnetic alloy ribbons; amorphous ribbons are amorphous soft magnetic alloy ribbons; metallic soft magnetic tapes include, but are not limited to, industrial pure iron ribbons, Fe-Si ribbons, and permalloy ribbons.

[0026] Please refer to Figures 1 to 12 A shielding sheet for a wireless charging module includes an outer magnetic sheet 2 and a central magnetic sheet 3. The outer magnetic sheet 2 has a through hole 4, and the central magnetic sheet 3 is disposed in the through hole 4. A gap 5 is formed between the peripheral wall of the central magnetic sheet 3 and the wall surface of the through hole 4. The outer magnetic sheet 2 includes at least one first magnetic conductive layer 6, which is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape. The central magnetic sheet 3 includes at least one second magnetic conductive layer 7, which is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape.

[0027] The structure / working principle of this invention is briefly described as follows: Magnetic lines of force parallel to the outer magnetic sheet 2 will induce eddy currents perpendicular to the outer magnetic sheet 2. Since the nanocrystalline ribbon, amorphous ribbon, or metal soft magnetic tape in the outer magnetic sheet 2 is very thin (only 10-30 μm), and there is insulating polymer glue between the layers, the outer magnetic sheet 2 itself cannot generate large eddy currents. Although the unfragmented central magnetic sheet 3 will lead to a slight increase in loss, its higher permeability will improve the magnetic focusing ability of the central magnetic sheet 3, which will greatly improve the charging efficiency. At the same time, its process is simple and does not require additional process steps.

[0028] As can be seen from the above description, the beneficial effects of the present invention are as follows: Since the outer magnetic sheet 2 is perpendicular to the direction of the induced eddy current, when the outer magnetic sheet 2 has multiple layers of first magnetic conductive layers 6 stacked, there is insulating glue between the stacked first magnetic conductive layers 6. Therefore, no matter how high the magnetic loss μ" of the outer magnetic sheet 2 is, it will not generate long free path eddy currents (when the outer magnetic sheet 2 has only one layer of first magnetic conductive layer 6, the thickness of a single layer of first magnetic conductive layer 6 is relatively thin (thickness ≤30μm), and long free path eddy currents will not be generated). Therefore, the outer magnetic sheet 2 maintains both ultra-high magnetic permeability and low eddy current loss; in addition, although the magnetic field is in the central magnetic sheet Eddy currents are generated within the magnetic sheet surface, but the central magnetic sheet 3 and the outer ring magnetic sheet 2 are isolated by a gap 5, so long free-path eddy currents will not appear on the central magnetic sheet 3. Through simulation, compared with traditional shielding sheets, this shielding sheet has fewer layers of outer ring magnetic sheet 2 and central magnetic sheet 3 under the same shielding performance conditions, which is conducive to the miniaturization and thinning of the shielding sheet. At the same time, the module charging efficiency and saturation current are also improved. Moreover, it does not require the addition of "air gap" or "insulation crack" processes to the material, which can shorten the process, thereby improving the product yield and reducing the production cost of wireless charging modules.

[0029] Furthermore, the outer magnetic sheet 2 and the central magnetic sheet 3 have the same thickness.

[0030] Furthermore, the material of the first magnetic conductive layer 6 is the same as that of the second magnetic conductive layer 7, and the outer magnetic sheet 2 and the central magnetic sheet 3 are cut from the same magnetic conductive sheet.

[0031] Furthermore, the material of the first magnetic layer 6 is different from that of the second magnetic layer 7.

[0032] As can be seen from the above description, the material of the first magnetic layer 6 and the material of the second magnetic layer 7 can be the same or different. For the convenience of procurement and manufacturing, it is preferred that the two are the same.

[0033] When the material of the first magnetic layer 6 is the same as that of the second magnetic layer 7, during processing, the center magnetic sheet 3 and the outer magnetic sheet 2 can be obtained simultaneously by directly cutting the slit 5 on the magnetic sheet using mechanical cutting, laser cutting, or other cutting methods. This greatly improves the production efficiency of the shielding sheet and effectively reduces its manufacturing cost. When the material of the first magnetic layer 6 is different from that of the second magnetic layer 7, the center magnetic sheet 3 can be directly cut from the magnetic sheet using mechanical cutting, laser cutting, or other cutting methods, and the outer magnetic sheet 2 can be cut from another magnetic sheet of a different material. Then, the two are combined. It is easy to understand that when the materials of the first and second magnetic layers are the same (such as both being nanocrystalline materials), the center magnetic sheet 3 and the outer magnetic sheet 2 can also be cut from different magnetic sheets. In detail, the center magnetic sheet 3 is first cut from one magnetic sheet using mechanical cutting, laser cutting, or other cutting methods, and the outer magnetic sheet 2 is cut from another magnetic sheet of the same material. Then, the two are assembled together.

[0034] Furthermore, the central magnetic sheet 3 has a first cutting pattern 8, which cuts each of the second magnetic conductive layers 7 into multiple first small pieces.

[0035] As can be seen from the above description, when cutting the gap 5, the central magnetic sheet 3 can be cut to a certain extent, so that the central magnetic sheet 3 forms a fragmented effect, thereby reducing the magnetic loss of the central magnetic sheet 3 and helping to further improve the charging efficiency.

[0036] Furthermore, the outer magnetic sheet 2 has a second cutting pattern 14, which cuts each of the first magnetic conductive layers 6 into multiple second small pieces.

[0037] As described above, when cutting the slit 5, the outer magnetic sheet 2 can be cut to a certain extent, so that the outer magnetic sheet 2 forms a fragmented effect, thereby reducing the magnetic loss of the outer magnetic sheet 2 and further improving the charging efficiency.

[0038] Furthermore, the outer magnetic sheet 2 includes multiple layers of first magnetic conductive layers 6 connected by insulating adhesive layers 9; and / or, the central magnetic sheet 3 includes multiple layers of second magnetic conductive layers 7 connected by insulating adhesive layers 9.

[0039] As can be seen from the above description, the thickness of the outer magnetic sheet 2 and the central magnetic sheet 3 can be selected according to actual needs.

[0040] Furthermore, the top surface of the central magnetic sheet 3 is coplanar with the top surface of the outer ring magnetic sheet 2 and is connected by a first adhesive layer 11; and / or, the bottom surface of the central magnetic sheet 3 is coplanar with the bottom surface of the outer ring magnetic sheet 2 and is connected by a second adhesive layer 12.

[0041] Furthermore, the gap 5 is filled with air or a non-magnetic material.

[0042] As can be seen from the above description, non-magnetic materials include, but are not limited to, non-magnetic adhesives, non-magnetic films, non-magnetic paper, etc.

[0043] The wireless charging module includes a charging coil 1 and a shielding sheet for the wireless charging module, wherein the central magnetic sheet 3 is disposed corresponding to the hollow area of ​​the charging coil 1.

[0044] As described above, the wireless charging module has the advantages of high charging efficiency and low manufacturing cost. The charging coil 1 can be optionally attached to the bottom surface of the outer magnetic sheet 2.

[0045] Furthermore, the inner edge surface 10 of the charging coil 1 is coplanar with the peripheral wall of the central magnetic sheet 3.

[0046] As described above, the coplanarity of the inner edge surface 10 of the charging coil 1 and the peripheral wall of the central magnetic sheet 3 prevents magnetic leakage. This means that the magnetic lines of force passing through the hollow region of the charging coil 1 directly reach the outer magnetic sheet 2, which helps ensure the magnetic focusing performance of the central magnetic sheet 3 and guarantees the charging efficiency of the wireless charging module. It is easy to understand that the inner edge surface 10 of the charging coil 1 is the inner diameter surface of the charging coil 1, which is a continuous annular surface perpendicular to the outer magnetic sheet 2.

[0047] Example 1

[0048] Please refer to Figures 1 to 5 The first embodiment of the present invention is as follows: Please refer to... Figures 1 to 3 A wireless charging module includes a charging coil 1 and a shielding sheet for the wireless charging module. In this embodiment, the charging coil 1 is bonded to the bottom of the shielding sheet for the wireless charging module.

[0049] The shielding sheet for the wireless charging module includes an outer magnetic sheet 2 without fragmentation and a central magnetic sheet 3 without fragmentation. The outer magnetic sheet 2 has a through hole 4, and the central magnetic sheet 3 is disposed within the through hole 4 and corresponds to the hollow area of ​​the charging coil 1. A gap 5 exists between the peripheral wall of the central magnetic sheet 3 and the wall of the through hole 4. The outer magnetic sheet 2 includes at least one first magnetic conductive layer 6, which is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape. The central magnetic sheet 3 includes at least one second magnetic conductive layer 7, which is also a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape. The gap 5 is a continuous and complete ring.

[0050] Furthermore, the gap 5 is filled with air or a non-magnetic material. The non-magnetic material can be a non-magnetic adhesive (such as a polymer insulating adhesive), a non-magnetic film, a non-magnetic paper, or other non-magnetic substances.

[0051] To facilitate processing and reduce the manufacturing costs of the shielding sheet and wireless charging module, in this embodiment, the first magnetic layer 6 is made of the same material as the second magnetic layer 7, and the outer magnetic sheet 2 and the central magnetic sheet 3 have the same thickness. The outer magnetic sheet 2 and the central magnetic sheet 3 are cut from the same magnetic sheet. It is readily understood that in other embodiments, the materials of the first magnetic layer 6 and the second magnetic layer 7 can be different. In other words, the central magnetic sheet 3 and the outer magnetic sheet 2 are cut from magnetic sheets of different materials. For example, the first magnetic layer 6 may be made of amorphous ribbon, while the second magnetic layer 7 may be made of nanocrystalline ribbon. Similarly, the thicknesses of the outer magnetic sheet 2 and the central magnetic sheet 3 can also be different. For example, the thickness of the central magnetic sheet 3 may be greater than the thickness of the outer magnetic sheet 2. This allows a portion of the central magnetic sheet 3 to extend into the hollow area of ​​the charging coil 1, thereby improving the shielding performance of the central magnetic sheet 3 and further improving the charging efficiency of the wireless charging module.

[0052] Preferably, the outer magnetic sheet 2 includes multiple layers of first magnetic conductive layers 6 connected by insulating adhesive layers 9; and / or, the central magnetic sheet 3 includes multiple layers of second magnetic conductive layers 7 connected by insulating adhesive layers 9. More preferably, the number of first magnetic conductive layers 6 is two or three, and the number of second magnetic conductive layers 7 is two or three. In this embodiment, the first and second magnetic conductive layers are nanocrystalline ribbons, and the thickness of the nanocrystalline ribbons is 10-30 μm.

[0053] To ensure the magnetic focusing effect of the central magnetic sheet 3, prevent magnetic leakage, and further improve the charging efficiency of the wireless charging module, preferably, the inner edge surface 10 of the charging coil 1 is coplanar with the peripheral wall of the central magnetic sheet 3. It is easily understood that the inner edge surface 10 of the charging coil 1 is annular, and all points of the wireless charging coil 1 closest to its own central axis are located on the inner edge surface 10.

[0054] The top surface of the central magnetic sheet 3 is coplanar with the top surface of the outer ring magnetic sheet 2 and is connected by a first adhesive layer 11; and / or, the bottom surface of the central magnetic sheet 3 is coplanar with the bottom surface of the outer ring magnetic sheet 2 and is connected by a second adhesive layer 12. The first adhesive layer 11 and the second adhesive layer 12 are insulating adhesives, and in this embodiment, the first adhesive layer 11 and the second adhesive layer 12 are acrylic adhesive layers.

[0055] Because the outer magnetic sheet 2 is perpendicular to the direction of the induced eddy current and has a thinner thickness, and because there is an insulating adhesive layer 9 between the stacked nanocrystalline ribbons, no matter how high the magnetic loss μ" of the outer magnetic sheet 2 is, it will not generate long-free-path eddy currents. Therefore, the outer magnetic sheet 2 can maintain ultra-high magnetic permeability without generating high eddy current losses. In addition, although the eddy currents generated by the magnetic field in the central magnetic sheet 3 are within the surface of the magnetic sheet, the higher permeability will greatly improve the charging efficiency and reduce the module loss. Moreover, the central magnetic sheet 3 and the outer magnetic sheet 2 are cut from the same magnetic sheet, so the process is simpler and no additional process steps are required, achieving cost savings. Compared with traditional magnetic shielding sheets, this shielding sheet does not require the process of adding "air gaps" or "insulation cracks" to the material, which can shorten the process. At the same time, under the condition of the same shielding performance, fewer magnetic layers are stacked, which is conducive to the miniaturization and thinning of the shielding sheet. At the same time, the charging efficiency and saturation current are also improved.

[0056] The above-mentioned method for fabricating wireless charging modules (taking nanocrystalline ribbon material as an example)

[0057] Step 1: Provide nanocrystalline ribbon and perform heat treatment on the nanocrystalline ribbon;

[0058] Step 2: Coat the nanocrystalline ribbon obtained in Step 1 with adhesive;

[0059] Step 3: Stack N coated nanocrystalline ribbons and bond adjacent nanocrystalline ribbons together to obtain a nanocrystalline magnetic sheet (i.e., the aforementioned magnetic conductive sheet), where N is an integer greater than or equal to 1; preferably, N is 2 or 3.

[0060] Step 4: The nanocrystalline magnetic sheet is contoured and slit 5 is cut to obtain the outer magnetic sheet 2 and the central magnetic sheet 3;

[0061] Step 7: Attach the top surface of the central magnetic sheet and the top surface of the outer magnetic sheet 2 to the same adhesive layer (i.e., the aforementioned first adhesive layer 11).

[0062] After the assembly personnel install the charging coil 1, that is, after the top surface of the charging coil 1 is attached to the bottom of the outer magnetic sheet 2 and the inner edge surface 10 of the charging coil 1 is aligned with the peripheral wall of the central magnetic sheet 3, the bottom surface of the charging coil 1 and the bottom surface of the central magnetic sheet 3 need to be attached to an insulating layer (i.e., the third adhesive layer 13) to complete the production of the wireless charging module.

[0063] The inventor manufactured a batch of samples and tested them.

[0064] Nanocrystalline alloy strip grade: 1K107b, thickness: 20μm.

[0065] The nanocrystalline ribbon is heat-treated using a heat treatment furnace (e.g., a nitrogen furnace). The specific heat treatment process is as follows: First, the nanocrystalline ribbon is heated to 550°C in the furnace, then held at that temperature for 2 hours, and then cooled to room temperature at a rate of 600°C / h before being removed from the furnace.

[0066] The heat-treated strip is coated with adhesive on one side; the nanocrystalline strip coated with adhesive on one side is then laminated to obtain three layers of nanocrystal wafers (i.e., the aforementioned magnetic conductive sheet).

[0067] The obtained nanocrystals are die-cut. According to the outer dimensions of the wireless charging module design and the inner diameter of the charging coil 1, the three layers of nanocrystals are die-cut with gaps 5, and the high permeability nanocrystalline magnetic material (i.e., the central magnetic sheet 3) located in the center is retained to obtain a shielding sheet.

[0068] Testing: The prepared sample 1 was assembled with components such as the charging coil 1 to obtain a wireless charging module, and the electrical performance of the wireless charging module was tested. In order to better compare with the shielding sheet made by the traditional process, the inventors also added a wireless charging module with a 4-layer nanocrystalline shielding sheet made by the traditional process as a control group. The test results of the samples are shown in Table 1.

[0069] Table 1 Comparison of Sample Test Results

[0070] Sample number Coil inductance L / μH Quality factor Q AC resistance Rs / mΩ Sample 1 8.11 23.83 214.46 control group 8.02 19.88 251.21

[0071] As shown in Table 1, the inductance of Sample 1 was higher than that of the control group, and the Q value also increased to a certain extent. In addition, its AC loss also decreased to a certain extent.

[0072] Next, the saturation current performance of sample 1 and the control group was compared using a saturation current testing platform. The test results are shown in Table 2.

[0073] Table 2 Comparison of Saturation Current Tests

[0074]

[0075] As shown in Table 2, through comparative analysis of saturation current, the saturation current performance of sample 1 is much higher than that of the control group.

[0076] Finally, the charging efficiency of Sample 1 and the control group was compared using a 15W platform, and the test results are shown in Table 3.

[0077] Table 3. Comparison of Charging Efficiency Tests for 15W Platforms

[0078] As shown in Table 3, through comparative analysis of charging efficiency, the charging efficiency of sample 1 is much higher than that of the control group.

[0079] Example 2

[0080] Please see Figures 4 to 8 Embodiment 2 of the present invention is an improvement based on Embodiment 1. The only difference from Embodiment 1 is that the central magnetic sheet 3 has a first cutting pattern 8. Specifically, the central magnetic sheet 3 is provided with a first cutting pattern 8, which cuts each of the second magnetic conductive layers 7 into multiple first small pieces. The first cutting pattern 8 includes multiple cutting grooves. Optionally, the cutting grooves of the first cutting pattern 8 can also be filled with air or non-magnetic material, similar to the gaps 5. The setting of the first cutting pattern 8 on the central magnetic sheet 3 allows the central magnetic sheet 3 to achieve a fragmented effect, thereby improving charging efficiency.

[0081] During processing, the first cutting pattern 8 can be processed while cutting the slit 5. In this embodiment, the first cutting pattern 8 is grid-shaped. In other embodiments, the first cutting pattern 8 can also be cross-shaped (e.g., Figure 5 As shown), a star-shaped pattern (such as...) Figure 6 As shown), radial (as shown) Figure 7 As shown), diagonal lines (such as...) Figure 8 (as shown) and other shapes.

[0082] The inventor manufactured sample 2 and tested sample 2.

[0083] Nanocrystalline alloy strip grade: 1K107b, thickness: 20μm.

[0084] The nanocrystalline ribbon is heat-treated using a heat treatment furnace (e.g., a nitrogen furnace). The specific heat treatment process is as follows: First, the nanocrystalline ribbon is heated to 550°C in the furnace, then held at that temperature for 2 hours, and then cooled to room temperature at a rate of 600°C / h before being removed from the furnace.

[0085] The heat-treated strip is coated with adhesive on one side; the nanocrystalline strip coated with adhesive on one side is then laminated to obtain three layers of nanocrystal wafers (i.e., the aforementioned magnetic conductive sheet).

[0086] The obtained nanocrystals are die-cut. According to the outer dimensions of the wireless charging module and the inner diameter of the charging coil 1, the three layers of nanocrystals are die-cut with gaps 5. At the same time, the first cutting pattern 8 in the form of a grid is die-cut, and the high magnetic permeability nanocrystalline magnetic material (i.e., the central magnetic sheet 3) located in the center is retained to obtain a shielding sheet. It should be noted that by designing the specific structure of the die-cutting blade on the die-cutting equipment, gaps 5 and the first cutting pattern 8 can be die-cut simultaneously when die-cutting nanocrystals.

[0087] Testing: The prepared sample 2 was assembled with components such as the charging coil 1 to obtain a wireless charging module, and the electrical performance of the wireless charging module was tested. In order to better compare with the shielding sheet made by traditional process, the inventors also added sample 1 from Example 1 for comparison. The test results of the sample are shown in Table 4.

[0088] Table 4 Comparison of Sample Test Results

[0089] Sample number Coil inductance L / μH Quality factor Q AC resistance Rs / mΩ Sample 1 8.11 23.83 214.46 Sample 2 8.05 23.94 208.72

[0090] As shown in Table 4, the inductance of sample 2 is slightly lower than that of sample 1, but the Q value is increased to a certain extent. In addition, its AC loss is reduced to a certain extent.

[0091] Next, the saturation current performance of Sample 1 and Sample 2 was compared and tested using a saturation current testing platform. The test results are shown in Table 5.

[0092] Table 5 Comparison of Saturation Current Tests

[0093]

[0094] As shown in Table 5, through comparative analysis of saturation current, the overall saturation current performance of sample 2 is slightly higher than that of sample 1.

[0095] Finally, the charging efficiency of Sample 1 and Sample 2 was compared using a 15W platform, and the test results are shown in Table 6.

[0096] Table 6. Comparison of Charging Efficiency Tests for 15W Platforms

[0097]

[0098]

[0099] As shown in Table 6, through comparative analysis of charging efficiency, the charging efficiency of sample 2 is slightly higher than that of sample 1.

[0100] Example 3

[0101] Please see Figure 9 and Figure 10, Embodiment 3 of the present invention is an improved solution proposed based on Embodiment 1. The difference from Embodiment 1 is only that the outer ring magnetic sheet 2 has a second cutting pattern 14, specifically: a second cutting pattern 14 is provided on the outer ring magnetic sheet 2, and the second cutting pattern 14 cuts each of the first magnetic conduction layers 6 into multiple second small pieces. The second cutting pattern 14 includes multiple cutting grooves. Optionally, the cutting grooves of the second cutting pattern 14 can also be filled with air or non-magnetic materials like the gap 5. The setting of the second cutting pattern 14 on the outer ring magnetic sheet 2 can make the outer ring magnetic sheet 2 obtain a fragmented-like effect, thereby improving the charging efficiency.

[0102] During processing, the processing of the second cutting pattern 14 can be carried out during the process of cutting the gap 5. In this embodiment, the second cutting pattern 14 is in a cross shape. In other embodiments, the second cutting pattern 14 can also be in a cross shape, radial shape (as Figure 10 shown), diagonal shape, etc.

[0103] The inventor manufactured Sample 3 and tested Sample 3.

[0104] The nanocrystalline alloy strip grade: 1K107b, with a thickness of 20 μm.

[0105] Use a heat treatment furnace (such as a nitrogen furnace) to heat-treat the nanocrystalline strip. The specific heat treatment process is as follows: First, let the nanocrystalline strip heat up in the furnace to 550 °C, then keep it warm for 2 hours, and then cool it to room temperature and take it out of the furnace at a speed of 600 °C / h.

[0106] Perform single-sided gluing on the heat-treated strip; laminate the single-sided glued nanocrystalline strip to obtain a 3-layer nanocrystalline wafer (i.e., the aforementioned magnetic conduction wafer).

[0107] Die-cut the obtained nanocrystalline wafer. Die-cut the gap 5 and the second cutting pattern 14 in a cross shape on the 3-layer nanocrystalline wafer according to the outer dimension of the wireless charging module design and the inner diameter dimension of the charging coil 1, and retain the high magnetic permeability nanocrystalline magnetic material (i.e., the central magnetic sheet 3) located in the center to obtain a shielding sheet; it should be noted that by designing the specific structure of the die-cutting knife on the die-cutting equipment, the gap 5 and the second cutting pattern 14 can be die-cut simultaneously when die-cutting the nanocrystalline wafer;

[0108] Test: Assemble the prepared Sample 3 with components such as the charging coil 1 to obtain a wireless charging module, and conduct electrical performance tests on the wireless charging module. In order to better compare with the shielding sheet made by the traditional process, the inventor also added Sample 1 in Embodiment 1 to form a comparison. The sample test results are shown in Table 7.

[0109] Table 7 Comparison table of sample test results

[0110] Sample number Coil inductance L / μH Quality factor Q AC resistance Rs / mΩ Sample 1 8.11 23.83 214.46 Sample 3 8.03 24.09 209.45

[0111] As shown in Table 7, the inductance of sample 3 is slightly lower than that of sample 1, but the Q value is increased to a certain extent. In addition, its AC loss is reduced to a certain extent.

[0112] Next, the saturation current performance of sample 1 and sample 3 was compared and tested using a saturation current testing platform. The test results are shown in Table 8.

[0113] Table 8 Comparison of Saturation Current Tests

[0114]

[0115] As shown in Table 8, through comparative analysis of saturation current, the overall saturation current performance of sample 3 is slightly higher than that of sample 1.

[0116] Finally, the charging efficiency of Sample 1 and Sample 3 was compared using a 15W platform, and the test results are shown in Table 9.

[0117] Table 9. Comparison of Charging Efficiency Tests for 15W Platforms

[0118] As shown in Table 9, through comparative analysis of charging efficiency, the charging efficiency of sample 3 is slightly higher than that of sample 1.

[0119] Example 4

[0120] Please see Figure 11 Embodiment 4 of the present invention is an improvement based on Embodiment 1. The only difference from Embodiment 1 is that the central magnetic sheet 3 has a first cutting pattern 8 and the outer magnetic sheet 2 has a second cutting pattern 14. Specifically, the central magnetic sheet 3 has a first cutting pattern 8, which cuts each of the second magnetic conductive layers 7 into multiple first small pieces, and the first cutting pattern 8 includes multiple cutting grooves; the outer magnetic sheet 2 has a second cutting pattern 14, which cuts each of the first magnetic conductive layers 6 into multiple second small pieces, and the second cutting pattern 14 includes multiple cutting grooves. Optionally, the cutting grooves of the first cutting pattern 8 and the second cutting pattern 14 can also be filled with air or non-magnetic material, like the gap 5.

[0121] During processing, the first cutting pattern 8 and the second cutting pattern 14 can be processed while cutting the slit 5. Optionally, the first cutting pattern 8 can be in the shape of a grid, cross, star, radial, or diagonal line; the second cutting pattern 14 can be in the shape of a star, radial, or diagonal line.

[0122] The inventors manufactured sample 4 and tested sample 4.

[0123] Nanocrystalline alloy strip grade: 1K107b, thickness: 20μm.

[0124] The nanocrystalline ribbon is heat-treated using a heat treatment furnace (e.g., a nitrogen furnace). The specific heat treatment process is as follows: First, the nanocrystalline ribbon is heated to 550°C in the furnace, then held at that temperature for 2 hours, and then cooled to room temperature at a rate of 600°C / h before being removed from the furnace.

[0125] The heat-treated strip is coated with adhesive on one side; the nanocrystalline strip coated with adhesive on one side is then laminated to obtain three layers of nanocrystal wafers (i.e., the aforementioned magnetic conductive sheet).

[0126] The obtained nanocrystals are die-cut. According to the outer dimensions of the wireless charging module design and the inner diameter of the charging coil 1, the three layers of nanocrystals are die-cut with gaps 5. At the same time, the first cutting pattern 8 in the grid shape and the second cutting pattern 14 in the cross shape are die-cut, and the high magnetic permeability nanocrystalline magnetic material (i.e., the central magnetic sheet 3) located in the center is retained to obtain the shielding sheet.

[0127] Testing: The prepared sample 4 was assembled with components such as the charging coil 1 to obtain a wireless charging module, and the electrical performance of the wireless charging module was tested. In order to better compare with the shielding sheet made by traditional process, the inventors also added sample 1 from Example 1 for comparison. The test results of the sample are shown in Table 10.

[0128] Table 10 Comparison of Sample Test Results

[0129] Sample number Coil inductance L / μH Quality factor Q AC resistance Rs / mΩ Sample 1 8.11 23.83 214.46 Sample 4 8.08 24.27 209.21

[0130] As shown in Table 10, the inductance of sample 4 is slightly lower than that of sample 1, but the Q value is increased to a certain extent. In addition, its AC loss is reduced to a certain extent.

[0131] Next, the saturation current performance of sample 1 and sample 4 was compared and tested using a saturation current test platform. The test results are shown in Table 11.

[0132] Table 11 Comparison of Saturation Current Tests

[0133]

[0134] As shown in Table 11, through comparative analysis of saturation current, the overall saturation current performance of sample 4 is slightly higher than that of sample 1.

[0135] Finally, the charging efficiency of Sample 1 and Sample 4 was compared using a 15W platform, and the test results are shown in Table 12.

[0136] Table 12 Comparison of Charging Efficiency Tests for 15W Platforms

[0137] As shown in Table 12, through comparative analysis of charging efficiency, the charging efficiency of sample 4 is slightly higher than that of sample 1.

[0138] Example 5

[0139] Please see Figure 12 Embodiment 5 of the present invention is an improvement based on Embodiment 1. The only difference from Embodiment 1 is that the central magnetic sheet 3 has a first cutting pattern 8 and the outer magnetic sheet 2 has a second cutting pattern 14. Specifically, the central magnetic sheet 3 has a first cutting pattern 8, which cuts each of the second magnetic conductive layers 7 into multiple first small pieces, and the first cutting pattern 8 includes multiple cutting grooves; the outer magnetic sheet 2 has a second cutting pattern 14, which cuts each of the first magnetic conductive layers 6 into multiple second small pieces, and the second cutting pattern 14 includes multiple cutting grooves. Optionally, the cutting grooves of the first cutting pattern 8 and the second cutting pattern 14 can also be filled with air or non-magnetic material, like the gap 5.

[0140] During processing, the first cutting pattern 8 and the second cutting pattern 14 can be processed while cutting the slit 5. Optionally, the first cutting pattern 8 can be in the shape of a grid, cross, star, radial, or diagonal line; the second cutting pattern 14 can be in the shape of a star, radial, or diagonal line.

[0141] The inventors manufactured sample 5 and tested sample 5.

[0142] Nanocrystalline alloy strip grade: 1K107b, thickness: 20μm.

[0143] The nanocrystalline ribbon is heat-treated using a heat treatment furnace (e.g., a nitrogen furnace). The specific heat treatment process is as follows: First, the nanocrystalline ribbon is heated to 550°C in the furnace, then held at that temperature for 2 hours, and then cooled to room temperature at a rate of 600°C / h before being removed from the furnace.

[0144] The heat-treated strip is coated with adhesive on one side; the nanocrystalline strip coated with adhesive on one side is then laminated to obtain three layers of nanocrystal wafers (i.e., the aforementioned magnetic conductive sheet).

[0145] The obtained nanocrystals are die-cut. According to the outer dimensions of the wireless charging module design and the inner diameter of the charging coil 1, the three layers of nanocrystals are die-cut with gaps 5. At the same time, the first cut pattern 8 and the second cut pattern 14 in the shape of a cross are die-cut, and the high permeability nanocrystalline magnetic material (i.e., the central magnetic sheet 3) located in the center is retained to obtain the shielding sheet.

[0146] Testing: The prepared sample 5 was assembled with components such as the charging coil 1 to obtain a wireless charging module, and the electrical performance of the wireless charging module was tested. In order to better compare with the shielding sheet made by traditional process, the inventors also added sample 1 from Example 1 for comparison. The test results of the sample are shown in Table 13.

[0147] Table 13 Comparison of Sample Test Results

[0148]

[0149]

[0150] As shown in Table 13, the inductance of sample 5 is slightly lower than that of sample 1, but the Q value is increased to a certain extent. In addition, its AC loss is reduced to a certain extent.

[0151] Next, the saturation current performance of sample 1 and sample 5 was compared and tested using a saturation current test platform. The test results are shown in Table 14.

[0152] Table 14 Comparison of Saturation Current Tests

[0153]

[0154] As shown in Table 14, through comparative analysis of saturation current, the overall saturation current performance of sample 5 is slightly higher than that of sample 1.

[0155] Finally, the charging efficiency of Sample 1 and Sample 5 was compared using a 15W platform, and the test results are shown in Table 15.

[0156] Table 15 Comparison of Charging Efficiency Tests for 15W Platforms

[0157]

[0158] As shown in Table 15, through comparative analysis of charging efficiency, the charging efficiency of sample 5 is slightly higher than that of sample 1.

[0159] In summary, the shielding sheet and wireless charging module provided by this invention, compared with traditional magnetic shielding sheets and charging modules, improve the charging efficiency and saturation current of the wireless charging module under the same shielding performance conditions. In addition, the elimination of the traditional "magnetic chipping" process in the production of the shielding sheet helps to reduce the manufacturing process of the shielding sheet and lower the manufacturing cost.

[0160] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A wireless charging module, comprising a charging coil and a shielding sheet for the wireless charging module, characterized in that: The shielding sheet for the wireless charging module includes an outer magnetic sheet without fragmentation and a central magnetic sheet without fragmentation. The outer magnetic sheet has a through hole, and the central magnetic sheet is disposed within the through hole. A gap exists between the peripheral wall of the central magnetic sheet and the wall of the through hole. The outer magnetic sheet includes at least one first magnetic conductive layer, which is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape. The central magnetic sheet includes at least one second magnetic conductive layer, which is a nanocrystalline ribbon, an amorphous ribbon, or a metal flexible magnetic tape. The gap is a continuous and complete ring. The central magnetic sheet is positioned corresponding to the hollow region of the charging coil; The inner edge of the charging coil is coplanar with the peripheral wall of the central magnetic sheet.

2. The wireless charging module according to claim 1, characterized in that: The outer magnetic sheet has the same thickness as the central magnetic sheet.

3. The wireless charging module according to claim 1, characterized in that: The first magnetic layer is made of the same material as the second magnetic layer, and the outer magnetic sheet and the central magnetic sheet are cut from the same magnetic sheet.

4. The wireless charging module according to claim 1, characterized in that: The material of the first magnetic layer is different from that of the second magnetic layer.

5. The wireless charging module according to claim 1, characterized in that: The central magnetic sheet has a first cutting pattern, which cuts each of the second magnetic conductive layers into multiple first small pieces.

6. The wireless charging module according to claim 1, characterized in that: The outer magnetic sheet has a second cutting pattern, which cuts each of the first magnetic conductive layers into multiple second small pieces.

7. The wireless charging module according to claim 1, characterized in that: The top surface of the central magnetic sheet is coplanar with the top surface of the outer magnetic sheet and is connected by a first adhesive layer; and / or, the bottom surface of the central magnetic sheet is coplanar with the bottom surface of the outer magnetic sheet and is connected by a second adhesive layer.

8. The wireless charging module according to claim 1, characterized in that: The gap is filled with air or non-magnetic material.

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