Magnetic laminate

Abstract

To provide a magnetic laminate that can suppress magnetic field leakage more effectively than conventional products.SOLUTION: A magnetic laminate has multiple magnetic layers, each made of soft magnetic metal foil. The multiple magnetic layers include at least one first magnetic layer and a second magnetic layer, which is a magnetic layer other than the first magnetic layer. The first magnetic layer has a first region, which is a region where there are no cracks penetrating the first magnetic layer in the thickness direction. The second magnetic layer has a second region, which is a region where there are cracks penetrating the second magnetic layer in the thickness direction and the second magnetic layer is divided into multiple magnetic pieces by the cracks. The first region and second region are stacked in a direction that coincides with the thickness direction of each of the multiple magnetic layers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to magnetic laminates. [Background technology]

[0002] A magnetic sheet having a thin plate-shaped magnetic material made of an amorphous alloy or a microcrystalline alloy is known (see, for example, Patent Document 1). In the magnetic sheet described in Patent Document 1, the thin plate-shaped magnetic material is divided into multiple pieces. Patent Document 1 states that by dividing the thin plate-shaped magnetic material into multiple magnetic pieces, the Q value can be improved when the magnetic sheet is used, for example, as a magnetic material for an inductor. Furthermore, when the magnetic sheet is used, for example, as a magnetic material for a magnetic shield, it is possible to reduce eddy current loss by dividing the current path of the thin plate-shaped magnetic material. Furthermore, Patent Document 1 states that the magnetic sheet is also effective as a magnetic shield provided on the power receiving device side of a contactless charging system (for example, on the side of an electronic device to be charged). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-112830 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have been considering using a magnetic laminate having multiple magnetic layers made of soft magnetic metal foil as a magnetic body to be placed between a power receiving coil and a metal plate for electromagnetic wave shielding on the power receiving device side of a contactless power transfer system. They thought that even in such a magnetic laminate, eddy current loss could be reduced by dividing each of the multiple magnetic layers into multiple magnetic pieces, as described in Patent Document 1.

[0005] However, when each of the multiple magnetic layers is divided into multiple magnetic pieces, even if the magnetic field is shielded by such a magnetic laminate, the magnetic field leakage cannot be sufficiently suppressed, and eddy currents may occur in the metal plate. Against this background, the present inventors have repeatedly studied measures to suppress magnetic field leakage. As a result, they have found that magnetic field leakage can be highly suppressed by making the structure of some of the multiple magnetic layers in the magnetic laminate different from that of the remaining magnetic layers, and have completed the technology of the present disclosure.

[0006] In one aspect of the present disclosure, it is desirable to provide a magnetic laminate that can suppress magnetic field leakage more effectively than conventional products. [Means for solving the problem]

[0007] (1) One aspect of the present disclosure is a magnetic laminate having multiple magnetic layers, each made of soft magnetic metal foil. The multiple magnetic layers include at least one first magnetic layer and a second magnetic layer that is a magnetic layer other than the first magnetic layer. The first magnetic layer has a first region that is a region where there is no crack penetrating the first magnetic layer in the thickness direction. The second magnetic layer has a second region that is a region where there is a crack penetrating the second magnetic layer in the thickness direction and the second magnetic layer is divided into multiple magnetic pieces by the crack. The first region and the second region are stacked in a direction that coincides with the thickness direction of each of the multiple magnetic layers.

[0008] The magnetic laminate thus configured has a laminated structure in which a first magnetic layer having the first region described above and a second magnetic layer having the second region described above are stacked. Therefore, compared to a magnetic body having only one or more magnetic layers with the same structure as the first magnetic layer, the magnetic laminate can suppress the generation of eddy currents in the magnetic layer and reduce heat generation associated with the generation of eddy currents. Furthermore, compared to a magnetic body having only one or more magnetic layers with the same structure as the second magnetic layer, the magnetic laminate can suppress magnetic flux leakage and improve magnetic shielding properties. Therefore, for example, if the magnetic laminate is used as a magnetic body disposed between a power receiving coil and a metal plate for electromagnetic wave shielding on the power receiving device side of a contactless power transfer system, the generation of eddy currents in the metal plate can be suppressed, thereby improving the power transmission efficiency in the contactless power transfer system.

[0009] The technology of the present disclosure may further include the following configuration. (2) In one embodiment of the present disclosure, the ratio of the number of first magnetic layers to the number of second magnetic layers may be 2%-26% first magnetic layers and 74%-98% second magnetic layers.

[0010] (3) In one embodiment of the present disclosure, the first magnetic layer may be disposed at a position biased toward one side of the stacking direction of the plurality of magnetic layers, and the second magnetic layer may be disposed at a position biased toward the other side. (4) In one embodiment of the present disclosure, the width of the cracks in the second magnetic layer may be 10 μm or less.

[0011] (5) In one embodiment of the present disclosure, the area of ​​each of the plurality of magnetic pieces in the second magnetic layer is 10 mm 2 It may be configured as follows: [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are perspective and cross-sectional views of the magnetic laminate. [Figure 2] FIG. 2 is an explanatory diagram for explaining the structure of the contactless power supply system. [Figure 3] FIG. 3 is a graph showing the relationship between the ratio of the second magnetic layer to the plurality of magnetic layers and the transmission efficiency. [Figure 4] FIG. 4 is a graph showing the relationship between the number of magnetic layers and the transmission efficiency. [Figure 5] FIG. 5 is a graph showing the relationship between the ratio of the second magnetic layer to the 50 magnetic layers and the transmission efficiency. [Figure 6] FIG. 6 is a graph showing the relationship between the distance between the magnetic material and the metal plate and the transmission efficiency. [Figure 7] FIG. 7 is a cross-sectional view of a magnetic laminated body exemplified as a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, the above-mentioned magnetic laminate will be described with reference to exemplary embodiments. (1) Structure of the magnetic laminate As shown in FIGS. 1A and 1B, the magnetic laminate 1 has multiple magnetic layers 11 and 12, multiple adhesive layers 13, one protective layer 14, and one release layer 15. Each of the multiple magnetic layers 11 and 12 is made of soft magnetic metal foil. In this embodiment, an Fe-based nanocrystalline alloy foil is used as the soft magnetic metal foil. The multiple magnetic layers 11 and 12 include at least one first magnetic layer 11 and a second magnetic layer 12 that is a magnetic layer other than the first magnetic layer 11. In this embodiment, the magnetic laminate 1 illustrated in FIGS. 1A and 1B has two first magnetic layers 11 and eight second magnetic layers 12.

[0014] The adhesive layers 13 are made of double-sided adhesive films and are laminated on both sides of the thickness direction of each of the magnetic layers 11, 12. Although not shown in FIG. 1B, in this embodiment, the double-sided adhesive film constituting the adhesive layers 13 has a structure in which an adhesive composition is laminated on both sides of a resin film serving as a base material. However, the adhesive layers 13 are not limited to the double-sided adhesive films described above. For example, the adhesive layers 13 may be adhesive layers with a single layer structure made of an adhesive composition (i.e., adhesive layers that do not have a base material such as those described above). Alternatively, the adhesive layers 13 may be adhesive layers made of a hot-melt resin composition.

[0015] The protective layer 14 is made of a PET film and is laminated on one of both sides in the thickness direction of the magnetic laminate 1. The release layer 15 is made of a release film and is laminated on one of both sides in the thickness direction of the magnetic laminate 1, opposite the protective layer 14.

[0016] The first magnetic layer 11 is 20 μm thick. The second magnetic layer 12 is 20 μm thick. The adhesive layer 13 is 5 μm thick. The protective layer 14 is 10 μm thick. The release layer 15 is 10 μm thick. The dimensions of the magnetic laminate 1 are 50 mm wide x 50 mm long x 0.275 mm thick.

[0017] The first magnetic layer 11 and the second magnetic layer 12 are made of the same soft magnetic metal foil, but differ in the presence or absence of cracks 21. The first magnetic layer 11 has a first region, which is a region where there are no cracks penetrating the first magnetic layer 11 in the thickness direction. The second magnetic layer 12 has a second region, which is a region where there are cracks 21 penetrating the second magnetic layer 12 in the thickness direction, and which is divided by the cracks 21 into multiple magnetic pieces 12A.

[0018] In the magnetic laminate 1, these first regions and second regions are stacked in a direction that coincides with the thickness direction of each of the multiple magnetic layers 11 and 12. In the case of this embodiment, the entire first magnetic layer 11 is the first region, and the entire second magnetic layer 12 is the second region. Therefore, the entire first magnetic layer 11 and the entire second magnetic layer 12 are stacked in a direction that coincides with the thickness direction of each of the multiple magnetic layers 11 and 12.

[0019] However, in an embodiment different from this embodiment, for example, a part of the first magnetic layer 11 may be the first region, and the remaining part may be a region other than the first region. Also, a part of the second magnetic layer 12 may be the second region, and the remaining part may be a region other than the second region. Even in this case, the first region and the second region are stacked in a direction that coincides with the thickness direction of each of the multiple magnetic layers 11, 12.

[0020] On the other hand, with respect to the regions other than the first region and the regions other than the second region, it may be uncertain whether they are stacked in a direction that coincides with the thickness direction of each of the multiple magnetic layers 11, 12. In other words, as long as a part of the first magnetic layer 11 corresponds to the first region and a part of the second magnetic layer 12 corresponds to the second region, the first magnetic layer 11 and the second magnetic layer 12 may include portions that do not correspond to the first region and the second region.

[0021] However, the first and second regions are the portions effective in making the magnetic laminate 1 function. Therefore, it is preferable that the portion that occupies the majority of the first magnetic layer 11 is configured as the first region, and the portion that occupies the majority of the second magnetic layer 12 is configured as the second region. As an example, it is preferable that the portion that occupies 80% or more of the entire first magnetic layer 11 is configured as the first region, and the portion that occupies 80% or more of the entire second magnetic layer 12 is configured as the second region. It is more preferable that the entire first magnetic layer 11 is configured as the first region, and the entire second magnetic layer 12 is configured as the second region.

[0022] The processing method for forming the cracks 21 in the second magnetic layer 12 is not particularly limited. For example, a laminate is formed as an intermediate product including the second magnetic layer 12, the adhesive layer 13, and the release layer 15, and the laminate is sandwiched between a pair of rollers and conveyed while being pressed. In this process, if a large number of protrusions are provided on the outer peripheral surface of one of the rollers and the laminate is pressed by the protrusions, cracks (i.e., cracks 21) can be formed in the second magnetic layer 12 that spread from the points where the tips of the protrusions hit. Alternatively, the cracks 21 can be formed by half-cutting the laminate as an intermediate product as described above using a cutting machine capable of half-cutting.

[0023] The following findings were obtained from the results of preliminary tests conducted by the present inventors prior to constructing the magnetic laminate 1. First, when forming the cracks 21, it is preferable to limit the width of the cracks 21 to 10 μm or less. With regard to the width of the cracks 21, from the viewpoint of improving the magnetic properties of the magnetic laminate 1, the narrower the width of the cracks 21, the better, and in this embodiment, the cracks 21 are configured to have a width of 1 μm or less.

[0024] Second, when forming the cleft 21, the area of ​​each magnetic piece 12A is set to 10 mm 2 With regard to the area of ​​the magnetic pieces 12A, from the viewpoint of improving the magnetic properties of the magnetic laminate 1, it is preferable to make the area of ​​the magnetic pieces 12A as small as possible. In this embodiment, the area of ​​each of the magnetic pieces 12A is 1 mm 2 It is configured as follows:

[0025] The structure of the magnetic laminate 1 described above is a typical example, and the number of the magnetic layers 11 and 12 can be changed as desired. For example, the number of the magnetic layers 11 and 12 may be 9 or less, or 11 or more, in addition to the 10 layers described above. In this case, the number of adhesive layers 13 can be increased or decreased depending on the number of magnetic layers 11 and 12. Assuming that the magnetic layers 11 and 12, adhesive layer 13, protective layer 14, and release layer 15 have the thicknesses described above, when the magnetic layers 11 and 12 are 20 layers, the thickness of the magnetic laminate 1 is 0.525 mm. When the magnetic layers 11 and 12 are 30 layers, the thickness of the magnetic laminate 1 is 0.775 mm. When the magnetic layers 11 and 12 are 40 layers, the thickness of the magnetic laminate 1 is 1.025 mm. When the magnetic layers 11 and 12 are 50 layers, the thickness of the magnetic laminate 1 is 1.275 mm.

[0026] (2) Evaluation test (part 1) Assuming that the magnetic laminate 1 is disposed on the power receiving device side of a contactless power transfer system, a contactless power transfer system 30 as shown in Fig. 2 was prepared as a system for evaluating transmission efficiency. The contactless power transfer system 30 includes a power transmitting coil 31, a magnetic body 32, and an electromagnetic wave shielding metal plate 33 as components corresponding to the power transmitting device side. The contactless power transfer system 30 also includes a power receiving coil 34, a magnetic body 35, an electromagnetic wave shielding metal plate 36, and a spacer 37 as components corresponding to the power receiving device side.

[0027] A spacer 41 is sandwiched between the power transmitting coil 31 and the power receiving coil 34. The power transmitting coil 31 is connected to a power source 45 via a pair of electric wires 43A. The power receiving coil 34 is connected to a load resistor 47 via a pair of electric wires 43B. A voltage probe 53A and a current probe 55A provided in an oscilloscope 51 are connected to the electric wire 43A, and a voltage probe 53B and a current probe 55B provided in the oscilloscope 51 are connected to the electric wire 43B.

[0028] The power transmitting coil 31 and the power receiving coil 34 are commercially available contactless power transfer coils (diameter 50 mm, inner diameter 14 mm, number of turns 84, inductance value 200 μH). The magnetic material 32 on the power transmitting device side is a ferrite plate (dimensions: length 50 mm × width 50 mm × thickness 4 mm). The metal plates 33 and 36 are aluminum plates (dimensions: length 80 mm × width 150 mm × thickness 4 mm). The spacer 37 is a resin plate (made of acrylic resin, dimensions: length 50 mm × width 50 mm × thickness 1 mm).

[0029] A resin plate (made of acrylic resin, dimensions: length 50 mm x width 50 mm x thickness 5 mm) is used as the spacer 41. A commercially available power supply for a 100W contactless power transfer system (input: commercial AC power supply AC100V / 50Hz, output: high frequency of 75kHz to 85kHz) is used as the power supply 45. The load resistor 47 is a commercially available product with a rated power of 300W and a resistance of 100Ω. The oscilloscope 51 is a commercially available product (product name: High-Speed ​​Multi-Recorder GR-7000 Series, manufactured by Keyence Corporation).

[0030] Using the contactless power supply system 30 described above, the relationship between the ratio of the first magnetic layer to the second magnetic layer and the transmission efficiency of the contactless power supply system was verified. As the magnetic body 35 on the power receiving device side, 22 types of magnetic laminates (hereinafter referred to as specimens C1 to C22) were prepared, which differed in the total number of magnetic layers and the ratio of first magnetic layers to second magnetic layers. Specifically, specimens C1 to C22 were all magnetic laminates configured with a length of 50 mm and a width of 50 mm. Specimens C1 to C11 each had 10 magnetic layers. Specimens C12 to C22 each had 20 magnetic layers. The number of first magnetic layers and second magnetic layers included in each specimen C1 to C22 differed as shown in Table 1 below.

[0031] Each of the above specimens C1 to C22 was placed as the magnetic body 35 on the power receiving device side of the contactless power transfer system 30, and the following evaluation test was carried out in an environment at room temperature of 25°C. The power supply 45 was configured so that when a switch operation was performed, power was supplied to the power transmission coil 31 for one minute. After the start of power supply from the power supply 45, when a predetermined time had passed and the power supply state had stabilized, the oscilloscope 51 measured the input effective voltage V i , input effective current I i , output effective voltage V o and output effective current I o During the measurement period, the oscilloscope 51 starts measuring the input effective voltage V i , input effective current I i , output effective voltage V o and output effective current I o Each value of η was measured 25 times and the average value was output. These output values ​​were substituted into the following formula (I) to calculate the transmission efficiency η.

[0032]

number

[0033] The total number of magnetic layers, the number of first magnetic layers, the number of second magnetic layers, the proportion of the second magnetic layers, and the transmission efficiency η for each of specimens C1 to C22 are shown in Table 1. A graph showing the relationship between the proportion of the second magnetic layers and the transmission efficiency η for each of specimens C1 to C22 is shown in Figure 3.

[0034] [Table 1]

[0035] As is clear from Table 1 and Figure 3, when the proportion of the second magnetic layer is 80% to 90%, the transmission efficiency η is higher than when the proportion of the second magnetic layer is 100%. When the proportion of the second magnetic layer is 80% to 90%, the magnetic field leaks toward the first magnetic layer. However, the presence of the first magnetic layer suppresses the leakage of the magnetic field toward the metal plate, suppressing the generation of eddy currents in the metal plate, thereby reducing heat loss in the metal plate. Although eddy currents are generated in the first magnetic layer, the surface resistance of the first magnetic layer is greater than that of the metal plate. Therefore, even if eddy currents are generated in the first magnetic layer, eddy current loss is reduced compared to when eddy currents are generated in the metal plate. As a result, it is inferred that the transmission efficiency η will be higher when the proportion of the second magnetic layer is 80% to 90%.

[0036] Furthermore, when the proportion of the second magnetic layer was 30% or less, the eddy currents generated in the first magnetic layer increased, and the magnetic laminate tended to heat up. When the proportion of the second magnetic layer was 100%, the magnetic field leaked to the metal plate, increasing the eddy currents generated in the metal plate, and the metal plate tended to heat up. It is presumed that the increase in heat loss due to such eddy currents will lead to a corresponding decrease in the transmission efficiency η.

[0037] (3) Evaluation test (part 2) Using the contactless power supply system 30 used in the above evaluation test (part 1), the relationship between the ratio of the first magnetic layer to the second magnetic layer and the transmission efficiency of the contactless power supply system was further verified.

[0038] As the magnetic body 35 on the power receiving device side, 20 types of magnetic laminates (hereinafter referred to as specimens D1 to D20) were prepared, each differing in the total number of magnetic layers and the ratio of the first magnetic layer to the second magnetic layer. Specifically, specimens D1 to D20 are all magnetic laminates configured with a length of 50 mm and a width of 50 mm. In specimens D1 to D5, the ratio of the second magnetic layer is 70%. In specimens D6 to D10, the ratio of the second magnetic layer is 80%. In specimens D11 to D15, the ratio of the second magnetic layer is 90%. In specimens D16 to D20, the ratio of the second magnetic layer is 100%.

[0039] Additionally, specimens D1, D6, D11, and D16 have a total of 10 magnetic layers. Specimens D2, D7, D12, and D17 have a total of 20 magnetic layers. Specimens D3, D8, D13, and D18 have a total of 30 magnetic layers. Specimens D4, D9, D14, and D19 have a total of 40 magnetic layers. Specimens D5, D10, D15, and D20 have a total of 50 magnetic layers.

[0040] The proportion of the second magnetic layer, the total number of magnetic layers, the number of first magnetic layers, the number of second magnetic layers, and the transmission efficiency η for each of specimens D1 to D20 are shown in Table 2. A graph showing the relationship between the total number of magnetic layers and the transmission efficiency η for each of specimens D1 to D20 is shown in Figure 4.

[0041] [Table 2]

[0042] As is clear from Table 2 and Figure 4, even when the proportion of the second magnetic layer is different, the transmission efficiency η tends to increase as the total number of magnetic layers increases. Furthermore, when the proportion of the second magnetic layer is 80% to 90%, the transmission efficiency η is higher than when the proportion of the second magnetic layer is 70% or 100%. These results are consistent with the evaluation results from the above evaluation test (part 1).

[0043] (4) Evaluation test (part 3) Using the contactless power supply system 30 used in the above evaluation test (part 1), the relationship between the ratio of the first magnetic layer to the second magnetic layer and the transmission efficiency of the contactless power supply system was further verified.

[0044] As the magnetic body 35 on the power receiving device side, 21 types of magnetic laminates (hereinafter referred to as specimens E1 to E21) with different ratios of the first magnetic layer to the second magnetic layer were prepared. Specifically, specimens E1 to E21 were all magnetic laminates configured with a length of 50 mm and a width of 50 mm. Based on the evaluation results of the above evaluation test (part 2), in evaluation test (part 3), the total number of magnetic layers in specimens E1 to E21 was set to 50. Furthermore, the ratio of the second magnetic layer was changed within a range of 20% to 100%, and especially within the range of 70% to 100%, the ratio of the second magnetic layer was changed in 2% increments.

[0045] The total number of magnetic layers, the number of first magnetic layers, the number of second magnetic layers, the proportion of the second magnetic layers, and the transmission efficiency η for each of specimens E1 to E21 are shown in Table 3. A graph showing the relationship between the proportion of the second magnetic layers and the transmission efficiency η for each of specimens E1 to E21 is shown in Figure 5.

[0046] [Table 3]

[0047] As is clear from Table 3 and Fig. 5, when the proportion of the second magnetic layer is 74% to 98%, the transmission efficiency η is higher than when the proportion of the second magnetic layer is 100%. In particular, when the proportion of the second magnetic layer is 76% to 96%, the transmission efficiency η exceeds 78.0%, which is excellent. When the proportion of the second magnetic layer is 78% to 92%, the transmission efficiency η exceeds 78.1%, which is even more excellent. When the proportion of the second magnetic layer is 86% to 88%, the transmission efficiency η exceeds 78.2%, which is the most excellent.

[0048] (5) Evaluation Test (Part 4) Using the contactless power supply system 30 used in the above evaluation test (part 1), the relationship between the distance between the second magnetic layer and the metal plate and the transmission efficiency of the contactless power supply system was verified.

[0049] As the magnetic body 35 on the power receiving device side, two types of magnetic laminates (hereinafter referred to as specimens F1 and F2) with different ratios of the first magnetic layer to the second magnetic layer and a 1 mm thick plate-shaped ferrite (hereinafter referred to as specimen F3) were prepared. Specifically, specimens F1 and F2 were both magnetic laminates configured with a length of 50 mm and a width of 50 mm. The total number of magnetic layers in specimens F1 and F2 was 10, and the ratio of the second magnetic layer was 80% for specimen F1 and 100% for specimen F2.

[0050] For each of the above specimens F1 to F3, the thickness of the spacer 37 was changed in five ways, and the distance between the magnetic body 35 and the metal plate 36 was changed in five ways. More specifically, the thickness of the spacer 37 was changed in 1 mm increments within a range of 1 mm to 5 mm.

[0051] The distance from the metal plate 36 and the transmission efficiency η for each of the specimens F1 to F3 are shown in Table 4. Also, a graph showing the relationship between the distance from the metal plate 36 and the transmission efficiency η for each of the specimens F1 to F3 is shown in FIG.

[0052] [Table 4]

[0053] As is clear from Table 4 and Fig. 6, when the proportion of the second magnetic layer is 80%, the transmission efficiency η is higher than when the proportion of the second magnetic layer is 100%. When the proportion of the second magnetic layer is 80%, the transmission efficiency η is higher than when the magnetic body 35 is made of ferrite with a thickness of 1 mm. In all of the cases of specimens F1 to F3, the transmission efficiency η increases as the distance between the magnetic body 35 and the metal plate 36 increases.

[0054] When the proportion of the second magnetic layer is 100%, the transmission efficiency η is 77.86% if the distance between the magnetic body 35 and the metal plate 36 is 4 mm. In contrast, when the proportion of the second magnetic layer is 80%, the transmission efficiency η is 77.89% if the distance between the magnetic body 35 and the metal plate 36 is 1 mm. Therefore, when comparing to the case where a transmission efficiency η of approximately 77.86% to 77.89% is to be ensured, by setting the proportion of the second magnetic layer to 80%, it is possible to achieve a space saving of 3 mm in the distance between the magnetic body 35 and the metal plate 36 compared to when the proportion of the second magnetic layer is 100%.

[0055] Furthermore, when the proportion of the second magnetic layer is 100%, if the distance between the magnetic body 35 and the metal plate 36 is 1 mm, the transmission efficiency η is 77.59%. In contrast, when the proportion of the second magnetic layer is 80%, if the distance between the magnetic body 35 and the metal plate 36 is 1 mm, the transmission efficiency η is 77.89%. Therefore, compared to when a distance of 1 mm is ensured between the magnetic body 35 and the metal plate 36, by setting the proportion of the second magnetic layer to 80%, it is possible to achieve a 0.3% increase in transmission efficiency η compared to when the proportion of the second magnetic layer is 100%.

[0056] (6) Effects As described above, the magnetic laminate 1 has a structure in which the first magnetic layer 11 having the first region as described above and the second magnetic layer 12 having the second region as described above are stacked. Therefore, compared to a magnetic body having only one or more magnetic layers with the same structure as the first magnetic layer 11, it is possible to suppress the generation of eddy currents in the magnetic layers and to suppress the heat generation associated with the generation of eddy currents. Furthermore, compared to a magnetic body having only one or more magnetic layers with the same structure as the second magnetic layer 12, it is possible to suppress magnetic flux leakage and improve magnetic shielding characteristics.

[0057] Therefore, for example, if the magnetic laminate 1 is used as the magnetic material 35 arranged between the receiving coil 34 and the metal plate 36 for electromagnetic wave shielding on the power receiving device side of the contactless power supply system 30, the generation of eddy currents in the metal plate 36 can be suppressed, and the power transmission efficiency in the contactless power supply system 30 can be improved.

[0058] (7) Other embodiments While the magnetic laminate has been described above using exemplary embodiments, the above-described embodiments are merely examples of one aspect of the present disclosure. In other words, the present disclosure is not limited to the above-described exemplary embodiments, and can be embodied in various forms without departing from the technical concept of the present disclosure.

[0059] For example, in the above embodiment, an Fe-based nanocrystalline alloy foil is used as an example of the soft magnetic metal foil, but a soft magnetic metal foil other than an Fe-based nanocrystalline alloy foil may be used. An example of a soft magnetic metal foil other than an Fe-based nanocrystalline alloy foil is an Fe-based amorphous alloy foil.

[0060] Furthermore, in the case of the magnetic laminate 1 exemplified in the above embodiment, one protective layer 14 is provided at a position that becomes the outer surface of the magnetic laminate 1, but a protective layer 14 may also be provided between the layers of the magnetic laminate 1. For example, as in the magnetic laminate 2 exemplified in FIG. 7, three protective layers 14 may be provided. In the case of the magnetic laminate 2, a protective layer 14 is provided at a position between two first magnetic layers 11 and four second magnetic layers 12, and at a position between four second magnetic layers 12 and four second magnetic layers 12.

[0061] With such a magnetic laminate 2, it is possible to configure the magnetic laminate 2 by stacking one first laminate and two second laminates using a first laminate including two first magnetic layers 11 and a second laminate including two second magnetic layers 12. By adopting such a configuration, it is possible to configure a magnetic laminate including a large number of magnetic layers by stacking multiple magnetic laminates including a small number of magnetic layers, and therefore it is possible to easily adjust the number of magnetic layers.

[0062] Note that multiple functions realized by one component exemplified in the above embodiments may be realized by multiple components. One function realized by one component exemplified in the above embodiments may be realized by multiple components. Multiple functions realized by multiple components exemplified in the above embodiments may be realized by one component. One function realized by multiple components exemplified in the above embodiments may be realized by one component. Part of the configuration exemplified in the above embodiments may be omitted. At least part of the configuration exemplified in one of the above embodiments may be added to or replaced with a configuration exemplified in an embodiment other than that one embodiment.

[0063] (8) Technical Ideas Disclosed in This Specification [Item 1] The magnetic layer has a plurality of magnetic layers each made of soft magnetic metal foil, the plurality of magnetic layers include at least one first magnetic layer and a second magnetic layer that is a magnetic layer other than the first magnetic layer; the first magnetic layer has a first region that is a region where no cracks penetrating the first magnetic layer in a thickness direction exist, the second magnetic layer has a second region in which a crack exists that penetrates the second magnetic layer in a thickness direction, and the second magnetic layer is divided into a plurality of magnetic pieces by the crack; the first region and the second region are stacked in a direction that coincides with the thickness direction of each of the plurality of magnetic layers; Magnetic laminate.

[0064] [Item 2] Item 1: The magnetic laminate according to item 1, The ratio of the number of the first magnetic layers to the number of the second magnetic layers is 2%-26% of the first magnetic layers and 74%-98% of the second magnetic layers. Magnetic laminate.

[0065] [Item 3] The magnetic laminate according to item 1 or 2, the first magnetic layer is disposed at a position biased toward one side of both sides in the stacking direction of the plurality of magnetic layers, and the second magnetic layer is disposed at a position biased toward the other side; Magnetic laminate.

[0066] [Item 4] The magnetic laminate according to any one of items 1 to 3, The width of the cracks in the second magnetic layer is configured to be 10 μm or less. Magnetic laminate.

[0067] [Item 5] Item 1 to Item 4: The magnetic laminate according to any one of items 1 to 4, The area of ​​each of the plurality of magnetic pieces in the second magnetic layer is 10 mm 2 It is configured to be: Magnetic laminate. [Explanation of symbols]

[0068] 1...magnetic laminate, 11, 12...magnetic layer (11...first magnetic layer, 12...second magnetic layer), 12A...magnetic piece, 13...adhesive layer, 14...protective layer, 15...peeling layer, 21...crack, 30...contactless power transfer system, 31...transmitting coil, 32, 35...magnetic material, 33, 36...metal plate, 34...receiving coil, 37, 41...spacer, 43A, 43B...electric wire, 45...power supply, 47...load resistor, 51...oscilloscope, 53A, 53B...voltage probe, 55A, 55B...current probe.

Claims

1. The magnetic layer has a plurality of magnetic layers each made of soft magnetic metal foil, the plurality of magnetic layers include at least one first magnetic layer and a second magnetic layer that is a magnetic layer other than the first magnetic layer; the first magnetic layer has a first region that is a region where no cracks penetrating the first magnetic layer in a thickness direction exist, the second magnetic layer has a second region in which a crack is present that penetrates the second magnetic layer in a thickness direction, and the second magnetic layer is divided into a plurality of magnetic pieces by the crack; the first region and the second region are stacked in a direction that coincides with the thickness direction of each of the plurality of magnetic layers; Magnetic laminate.

2. 2. The magnetic laminate according to claim 1, The ratio of the number of the first magnetic layers to the number of the second magnetic layers is 2% to 26% for the first magnetic layers and 74% to 98% for the second magnetic layers. Magnetic laminate.

3. 3. The magnetic laminate according to claim 1 or 2, the first magnetic layer is disposed at a position biased toward one side of both sides in the stacking direction of the plurality of magnetic layers, and the second magnetic layer is disposed at a position biased toward the other side; Magnetic laminate.

4. 3. The magnetic laminate according to claim 1 or 2, The width of the cracks in the second magnetic layer is set to 10 μm or less. Magnetic laminate.

5. 3. The magnetic laminate according to claim 1 or 2, The area of ​​each of the plurality of magnetic pieces in the second magnetic layer is 10 mm ２ It is configured to be: Magnetic laminate.

Images