Magnetic material and coil component containing the same

Abstract

The present invention provides a magnetic material that can improve the electrical characteristics of a coil when used as a magnetic path by being placed on the back of the coil, and a coil component equipped therewith. [Solution] The coil component 100 comprises a magnetic body 10 and a coil 20 that overlaps the magnetic body 10. The magnetic body 10 comprises a first magnetic body layer 11 and a second magnetic body layer 12 laminated on the first magnetic body layer 11. The first magnetic body layer 11 is made of a nanocrystalline alloy material, and the second magnetic body layer 12 is made of a composite magnetic material obtained by mixing magnetic powder F with a resin R. The coil 20 is positioned opposite the second magnetic body layer 12 of the magnetic body 10.

Description

Technical Field

[0001] The present disclosure relates to a magnetic material and a coil component including the same, and particularly to a magnetic material including a nanocrystalline alloy material and a coil component including the same.

Background Art

[0002] Patent Document 1 discloses a wireless power transmission device including a magnetic material made of a nanocrystalline alloy material. Since the nanocrystalline alloy material has a very high relative permeability, by disposing it on the back surface of the coil and using it as a magnetic path, it is possible to obtain high magnetic saturation characteristics.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the nanocrystalline alloy material has conductivity, there is a problem that the resistance value of the coil increases due to the influence of eddy currents and the Q value of the coil decreases.

[0005] In the present disclosure, a magnetic material and a coil component including the same that can improve the electrical characteristics of the coil when used as a magnetic path by being disposed on the back surface of the coil are described. 1]

Means for Solving the Problems

[0006] The magnetic material according to one aspect of the present disclosure includes a first magnetic material layer and a second magnetic material layer laminated on the first magnetic material layer. The first magnetic material layer is composed of a nanocrystalline alloy material, and the second magnetic material layer is composed of a composite magnetic material in which magnetic powder is mixed with resin.

[0007] A coil component according to one aspect of the present disclosure comprises the above-mentioned magnetic material and a coil that overlaps the magnetic material, wherein the coil is positioned opposite the second magnetic layer of the magnetic material. [Effects of the Invention]

[0008] According to this disclosure, a magnetic material capable of improving the electrical characteristics of a coil when used as a magnetic path by being placed on the back of the coil, and a coil component equipped therewith are provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram illustrating the basic configuration of a wireless power transmission device. [Figure 2] Figure 2 is a schematic plan view illustrating the configuration of a coil component 100 according to one embodiment of the technology described herein. [Figure 3] Figure 3(a) is a schematic cross-sectional view along line AA shown in Figure 2, and Figure 3(b) is a schematic cross-sectional view along line BB shown in Figure 2. [Figure 4] Figures 4(a) to 4(c) are schematic cross-sectional views illustrating variations in the structure of the coil component 100. [Figure 5] Figure 5 is a schematic plan view showing an example in which the first magnetic layer 11 consists of multiple nanocrystalline alloy tiles. [Modes for carrying out the invention]

[0010] The embodiments of the technology described herein will be described in detail below with reference to the attached drawings.

[0011] Figure 1 is a schematic diagram illustrating the basic configuration of a wireless power transmission device.

[0012] The wireless power transmission device shown in Figure 1 includes a coil component 100 and a coil component 200. Coil component 100 includes a magnetic material 10 and a coil 20 placed on its surface, and a power transmission circuit 301 is connected to the coil 20. Thus, coil component 100 and the power transmission circuit 301 constitute a power transmission device. Coil component 200 includes a magnetic material 10 and a coil 20 placed on its surface, and a power receiving circuit 302 is connected to the coil 20. Thus, coil component 200 and the power receiving circuit 302 constitute a power receiving device. The power transmission device and the power receiving device are arranged with a predetermined space between them so that their coils 20 face each other. In this state, when current is passed from the power transmission circuit 301 included in the power transmission device to the coil 20, the resulting magnetic flux links with the coil 20 included in the power receiving device, and power is supplied to the power receiving circuit 302. The magnetic material 10 included in coil components 100 and 200 functions as a magnetic path for the magnetic flux by being placed on the back of the coil 20. Furthermore, if the surface of the coil 20 is covered with an insulating material, the coil 20 and the magnetic material 10 may be in contact with each other, as shown in the example in Figure 1. Alternatively, the coil 20 may be placed between it and the magnetic material 10 with an insulating member in between.

[0013] The configurations of coil component 100 and coil component 200 may be the same or different. The configuration of coil component 100 will be explained in more detail below, using it as an example.

[0014] Figure 2 is a schematic plan view illustrating the configuration of a coil component 100 according to one embodiment of the technology described herein. Figure 3(a) is a schematic cross-sectional view along line AA shown in Figure 2, and Figure 3(b) is a schematic cross-sectional view along line BB shown in Figure 2.

[0015] As shown in Figures 2 and 3, the coil component 100 according to this embodiment comprises a magnetic body 10 and a coil 20 that overlaps the magnetic body 10 in the thickness direction. The magnetic body 10 includes a first magnetic body layer 11 and a second magnetic body layer 12 that are stacked on top of each other. The first magnetic body layer 11 and the second magnetic body layer 12 are composed of different magnetic materials. Specifically, the first magnetic body layer 11 is composed of a nanocrystalline alloy material, and the second magnetic body layer 12 is composed of a composite magnetic material obtained by mixing magnetic powder F with a resin R. The magnetic powder F contained in the second magnetic body layer 12 may have a flattened shape with its longitudinal direction being the plane direction perpendicular to the thickness direction. The magnetic powder F contained in the second magnetic body layer 12 is not particularly limited as long as it exhibits soft magnetic properties, and may be composed of a material mainly composed of Fe, for example. The first magnetic body layer 11 and the second magnetic body layer 12 may be bonded together via an adhesive layer 13 located between them.

[0016] The coil 20 overlaps the magnetic material 10 so as to face the second magnetic layer 12. In other words, the coil 20 is positioned opposite the second magnetic layer 12 of the magnetic material 10. The pattern width of the coil 20 may have a shape that becomes narrower as it approaches the magnetic material 10, as shown in Figure 3. In the example shown in Figure 3, the surface of the coil 20 facing the magnetic material 10 is curved, while the surface of the coil 20 facing away from the magnetic material 10 is almost flat. Such a cross-sectional shape is obtained by forming the coil 20 on a substrate that was present on the surface of the coil 20 facing away from the magnetic material 10, transferring the coil 20 so as to overlap the magnetic material 10, and then peeling off the substrate. As a result, since no substrate used to form the coil 20 remains, the overall thickness of the coil component 100 can be reduced. An insulating layer 14 made of acrylic resin or the like may be interposed between the coil 20 and the second magnetic layer 12. Furthermore, on the opposite side of the coil 20 as seen from the magnetic material 10, a metal sheet 30 may be provided, which is positioned opposite the first magnetic material layer 11 and facing the first magnetic material layer 11.

[0017] In the example shown in Figure 2, the coil 20 makes approximately 5 turns on the surface of the magnetic material 10. The outer peripheral end 21 of the coil 20 is connected to the terminal electrode 43 via wiring 41 provided on the flexible substrate 40. The inner peripheral end 22 of the coil 20 is connected to the terminal electrode 44 via wiring 42 provided on the flexible substrate 40. As shown in Figure 3(b), a portion of the flexible substrate 40 is placed within a slit 15 provided in the magnetic material 10, and the inner peripheral end 22 of the coil 20 is connected to the wiring 42 on the flexible substrate 40 via solder 50. Although not shown, the outer peripheral end 21 of the coil 20 is also connected to the wiring 41 on the flexible substrate 40 via solder 50.

[0018] With this configuration, when a magnetic flux is generated by passing current through the coil 20 via terminal electrodes 43 and 44, the magnetic material 10 functions as a magnetic path for the magnetic flux. As a result, almost no magnetic flux is applied to the metal sheet 30, and losses due to the metal sheet 30 are suppressed. Here, the first magnetic layer 11 contained in the magnetic material 10 is made of a nanocrystalline alloy material, so it has a very high relative permeability and exhibits excellent magnetic saturation characteristics. However, since the nanocrystalline alloy material is conductive, if the first magnetic layer 11 is used alone, the resistance of the coil 20 may increase and the Q value of the coil 20 may decrease due to the influence of eddy currents generated in the first magnetic layer 11. Considering this point, in this embodiment, a second magnetic layer 12 is added to the coil 20 side. The second magnetic layer 12 is composed of a composite magnetic material in which magnetic powder F is mixed with resin R. Although its relative permeability is lower than that of the first magnetic layer 11, placing it between the first magnetic layer 11 and the coil 20 improves the resistance and Q value of the coil 20. Moreover, since the composite magnetic material in which magnetic powder F is mixed with resin R can be applied in a thin layer of 100 μm or less, the overall thickness can be reduced compared to when a bulk ferrite sintered body or the like is used as the material for the second magnetic layer 12.

[0019] The relative permeability of the second magnetic layer 12 may be increased in the plane direction perpendicular to the thickness direction. This can be realized by using, as the magnetic powder F contained in the second magnetic layer 12, a magnetic powder F having a flat shape with the plane direction as the longitudinal direction.

[0020] The thickness T1 of the first magnetic layer 11 may be less than or equal to the thickness T2 of the second magnetic layer 12. In the example shown in FIG. 3, the thickness T1 of the first magnetic layer 11 is thinner than the thickness T2 of the second magnetic layer 12. The thickness T1 of the first magnetic layer 11 may be 10 μm or more and 30 μm or less. The thickness T2 of the second magnetic layer 12 may be 30 μm or more and 100 μm or less. Thus, when the thickness T1 of the first magnetic layer 11 is less than or equal to the thickness T2 of the second magnetic layer 12, it is possible to increase the relative permeability of the entire magnetic body 10 while reducing the thickness of the entire magnetic body 10.

[0021] The first magnetic layer 11 may be a sheet-like member not divided in the plane direction, or may be an aggregate of a plurality of tile-like members divided in the plane direction.

[0022] In the example shown in FIG. 4(a), the first magnetic layer 11 is composed of a nanocrystalline alloy sheet extending in the plane direction perpendicular to the stacking direction. That is, the first magnetic layer 11 is not divided in the plane direction and consists of a single nanocrystalline alloy sheet. According to this, it is possible to increase the relative permeability of the first magnetic layer 11. When using a nanocrystalline alloy sheet not divided in the plane direction as the material of the first magnetic layer 11, two or more nanocrystalline alloy sheets may be stacked and used. Also, in the example shown in FIG. 4(a), the nanocrystalline alloy sheet may have a plurality of micro cracks.

[0023] In the example shown in Figure 4(b), the first magnetic layer 11 is composed of multiple nanocrystalline alloy tiles divided in a planar direction perpendicular to the stacking direction. In other words, the first magnetic layer 11 is provided with slits 11A, and the first magnetic layer 11 is divided into multiple parts by the slits 11A. This reduces the eddy currents generated in the first magnetic layer 11. In the example shown in Figure 4(b), gaps may be present between the tiles, and multiple microcracks may be present in each nanocrystalline alloy tile.

[0024] In the example shown in Figure 4(c), two magnetic materials 10A and 10B are stacked. Both magnetic materials 10A and 10B may have the same configuration as the magnetic material 10 shown in Figure 4(b). In this way, by stacking multiple sets of magnetic materials 10 including the first magnetic material layer 11 and the second magnetic material layer 12, it is possible to increase the overall thickness without increasing the thickness of the first magnetic material layer 11 and the second magnetic material layer 12 individually, thereby improving the magnetic properties.

[0025] When the first magnetic layer 11 is divided into multiple nanocrystalline alloy tiles by providing a slit 11A, the planar shape of each tile may be a square, as shown in Figure 5. Figure 5 also shows the position of the coil 20. Reference numeral 23 in Figure 5 indicates the outermost edge of the coil 20, and reference numeral 24 in Figure 5 indicates the innermost edge of the coil 20. In the example shown in Figure 5, the size of one side of the nanocrystalline alloy tile divided by the slit 11A is smaller than the size in the planar direction of the opening region surrounded by the innermost edge 24 of the coil 20. This makes it possible to effectively reduce the eddy currents generated in the first magnetic layer 11. Also, in the example shown in Figure 5, the size of one side of the nanocrystalline alloy tile divided by the slit 11A is smaller than the coil width defined by the width of the outermost edge 23 and the innermost edge 24 of the coil 20. This makes it possible to more effectively reduce the eddy currents generated in the first magnetic layer 11.

[0026] The planar shape of the nanocrystalline alloy tile divided by slit 11A does not need to be square; it may be rectangular or triangular. If the planar shape of the nanocrystalline alloy tile divided by slit 11A is not square, the size of one side of the nanocrystalline alloy tile may be defined by the size of the longest side or by the size of the shortest side.

[0027] As described above, the coil component 100 according to this embodiment uses a magnetic material 10 in which a first magnetic layer 11 made of nanocrystalline alloy material and a second magnetic layer 12 made of a composite magnetic material obtained by mixing magnetic powder with resin are laminated. Therefore, it is possible to obtain high magnetic properties while reducing the overall thickness. For this reason, if the coil component 100 according to this embodiment is used as part of a power transmission device or part of a power receiving device for a wireless power transmission device, the resistance value and Q value of the coil 20 will be improved, making it possible to obtain high power transmission efficiency.

[0028] While embodiments of the technology described herein have been explained above, it goes without saying that the technology described herein is not limited to the embodiments described above, and various modifications are possible without departing from its spirit, and these modifications are also included within the scope of the technology described herein.

[0029] The technology relating to this disclosure includes, but is not limited to, the following configuration examples.

[0030] A magnetic material according to one aspect of this disclosure comprises a first magnetic layer and a second magnetic layer laminated on the first magnetic layer, wherein the first magnetic layer is made of a nanocrystalline alloy material and the second magnetic layer is made of a composite magnetic material obtained by mixing magnetic powder with resin. This makes it possible to reduce the overall thickness while improving the electrical properties of the coils when coils are stacked.

[0031] In the magnetic material described above, the first magnetic layer may include a plurality of nanocrystalline alloy tiles divided in a planar direction perpendicular to the stacking direction. This makes it possible to reduce the eddy currents generated within the first magnetic layer.

[0032] In the above-described magnetic material, the first magnetic layer may include a nanocrystalline alloy sheet extending in a planar direction perpendicular to the stacking direction. This makes it possible to increase the relative permeability of the first magnetic layer in the planar direction.

[0033] In the above-described magnetic material, the magnetic powder contained in the second magnetic layer may have a flattened shape. This makes it possible to increase the relative permeability of the second magnetic layer in the planar direction.

[0034] In the above-described magnetic material, the relative permeability of the first magnetic layer may be higher than that of the second magnetic layer. This makes it possible to increase the relative permeability of the entire magnetic material.

[0035] In the magnetic material described above, the thickness of the first magnetic layer may be less than or equal to the thickness of the second magnetic layer. This makes it possible to reduce the overall thickness of the magnetic material.

[0036] A coil component according to one aspect of this disclosure comprises the above-mentioned magnetic material and a coil that overlaps the magnetic material, wherein the coil is positioned opposite the second magnetic layer of the magnetic material. This makes it possible to reduce the resistance value of the coil and increase the Q value of the coil.

[0037] In the above coil component, the first magnetic layer includes a plurality of nanocrystalline alloy tiles divided in a planar direction perpendicular to the stacking direction, and the size of the nanocrystalline alloy tiles in the planar direction may be smaller than the size of the aperture region surrounded by the coil in the planar direction. This makes it possible to effectively reduce the eddy currents generated in the first magnetic layer.

[0038] The above coil component may further include a metal sheet positioned opposite the first magnetic layer of the magnetic material. Even when such a metal sheet is present, the magnetic flux is blocked by the magnetic material, making it possible to suppress the generation of eddy current losses.

[0039] In the above-described coil component, multiple sets of magnetic materials, including a first magnetic layer and a second magnetic layer, may be stacked. This makes it possible to obtain higher magnetic properties. [Explanation of Symbols]

[0040] 10,10A,10B Magnetic material 11 First magnetic layer 11A Slit 12 Second magnetic layer 13 Adhesive layer 14. Insulating layer 15 slits 20 coils 21 Outer edge 22 Inner end 23 Outermost edge 24 Innermost edge 30 Metal Sheets 40 Flexible circuit boards 41,42 Wiring 43,44 terminal electrode 50 Solder 100,200 coil components 301 Power transmission circuit 302 Power Receiving Circuit F magnetic powder R resin

Claims

1. The first magnetic layer and A second magnetic layer laminated on the first magnetic layer, Equipped with, The first magnetic layer is composed of a nanocrystalline alloy material, The aforementioned second magnetic layer is composed of a composite magnetic material obtained by mixing magnetic powder with resin. magnetic material.

2. The first magnetic layer includes a plurality of nanocrystalline alloy tiles divided in a planar direction perpendicular to the stacking direction, The magnetic material according to claim 1.

3. The first magnetic layer includes a nanocrystalline alloy sheet extending in a planar direction perpendicular to the stacking direction. The magnetic material according to claim 1.

4. The magnetic powder contained in the second magnetic layer has a flattened shape. The magnetic material according to claim 1.

5. The relative permeability of the first magnetic layer is higher than the relative permeability of the second magnetic layer. The magnetic material according to claim 1.

6. The thickness of the first magnetic layer is less than or equal to the thickness of the second magnetic layer. The magnetic material according to claim 1.

7. A magnetic material according to any one of claims 1 to 6, A coil overlapping the aforementioned magnetic material, Equipped with, The coil is positioned opposite the second magnetic layer of the magnetic material. Coil components.

8. The first magnetic layer includes a plurality of nanocrystalline alloy tiles divided in a planar direction perpendicular to the stacking direction, The size of the nanocrystalline alloy tile in the planar direction is smaller than the size of the opening region surrounded by the coil in the planar direction. The coil component according to claim 7.

9. The magnetic material further comprises a metal sheet disposed opposite to the first magnetic layer of the magnetic material. The coil component according to claim 7.

10. Multiple sets of the magnetic material, including the first magnetic layer and the second magnetic layer, are stacked. The coil component according to claim 7.

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