Magnetic coil, magnetic member, and wireless power supply device

Abstract

To improve a vibration resistance in a magnetic coil including a coil and a magnetic composite material.SOLUTION: In a magnetic coil including a planar coil and a magnetic composite material, the planar coil is in the form of a flat plate around which a wire is wound in a spiral shape and having a first coil surface and a second coil surface that is a back surface of the first coil surface, and the magnetic composite material includes a resin material and a magnetic particle contained in a resin material. The magnetic coil includes a coil layer having a first surface including the first coil surface of the planar coil and a second surface including the second coil surface of the planar coil, a first magnetic layer formed of a magnetic composite material and disposed on the first surface of the coil layer, and a second magnetic layer formed of the magnetic composite material and disposed on the second surface of the coil layer. At least one of the first magnetic layer and the second magnetic layer includes a third magnetic layer having a smaller content of the magnetic particle than a remaining region on the coil layer side, and the third magnetic layer contacts at least one part of the first surface or the second surface of the coil layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to magnetic coils that include planar coils and magnetic composite materials. [Background technology]

[0002] Conventionally, Litz wire or plate-shaped coils have been used for wireless power supply coils used in electric vehicles, and studies have been conducted to reduce AC resistance and achieve highly efficient power transmission. For example, in the technology described in Patent Document 1, an adhesive layer is provided on the outer surface of a conductor used in the coil, and a magnetic powder layer is provided in which magnetic powder is fixed by the adhesive layer. In addition, in the technology described in Non-Patent Document 1, a magnetic composite material (also called a magnetic composite material) in which magnetic particles are blended with a silicone resin is used to form a magnetic layer on the surface of a plate-shaped coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-018585 [Non-patent literature]

[0004] [Non-Patent Document 1] Shun Endo, Takahiro Kasai, Takeshi Utsubo, Tsutomu Mizuno, "Lightweight and Efficient Wireless Power Transfer Coils Using Magnetically Coated Aluminum Plates," IEICE Technical Report, vol.117, no.383, WPT2017-66(2018-01), pp.59-64 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a device such as a wireless power supply system using a coil coated with a magnetic composite material obtained by combining a resin material and a magnetic body as described in Patent Document 1 and Non-Patent Document 1 is mounted on an electric vehicle or the like as a battery power supply device, there is a possibility that cracks may occur in the magnetic layer, or that interfacial peeling may occur between the magnetic layer and the coil. Therefore, there has been a demand for improved vibration resistance in magnetic coils that include a coil and a magnetic composite material.

[0006] Such issues related to vibration resistance are common to magnetic components equipped with magnetic coils, wireless power supply devices equipped with such magnetic components, and devices that use magnetic coils in environments that are subject to vibration. [Means for solving the problem]

[0007] The present disclosure can be realized in the following forms. (1) According to one aspect of the present disclosure, there is provided a magnetic coil including a planar coil and a magnetic composite material. In this magnetic coil, the planar coil is formed by spirally winding a wire and has a flat plate shape having a first coil surface and a second coil surface that is a backside of the first coil surface. The magnetic composite material includes a resin material and magnetic particles contained in the resin material. The magnetic coil includes a coil layer having a first surface including the first coil surface of the planar coil and a second surface including the second coil surface of the planar coil, a first magnetic layer made of the magnetic composite material and disposed on the first surface of the coil layer, and a second magnetic layer made of the magnetic composite material and disposed on the second surface of the coil layer. At least one of the first magnetic layer and the second magnetic layer includes a third magnetic layer on the coil layer side, the third magnetic layer having a content of the magnetic particles lower than that of a remaining region, and the third magnetic layer contacts at least a portion of the first surface or the second surface of the coil layer.

[0008] The boundary between the planar coil and the magnetic composite material is prone to cracking and peeling due to vibration. According to the magnetic coil of the above embodiment, the third magnetic layer, which contains less magnetic particles than the remaining region, contacts at least a portion of the first or second surface of the coil layer. Because the third magnetic layer contains less magnetic particles than the remaining region and is highly flexible and less likely to become a fracture starting point, by being provided so as to contact at least a portion of the first or second surface of the coil layer, where cracking and peeling are likely to occur, cracking in the first and second magnetic layers can be suppressed, and peeling between the planar coil and the first and second magnetic layers can be suppressed. In other words, the vibration resistance of the magnetic coil can be improved.

[0009] (2) In the magnetic coil of the above embodiment, the cross-sectional shape of the wire of the planar coil may be approximately rectangular. In such a planar coil, stress tends to concentrate at the corners of the wire, which can easily become the starting point for fracture. Therefore, this configuration can suppress cracks in the first magnetic layer and the second magnetic layer due to vibration, and peeling between the planar coil and the first magnetic layer and the second magnetic layer.

[0010] (3) In the magnetic coil of the above aspect, the coil layer may have the planar coil and a magnetic portion made of the magnetic composite material, and the third magnetic layer may be disposed so as to be in contact with a region of the first surface or the second surface corresponding to the magnetic portion. With this configuration, the highly flexible third magnetic layer is disposed in a region that is likely to become a fracture starting point, thereby further suppressing cracks in the magnetic portion, first magnetic layer, second magnetic layer, etc. of the coil layer and peeling from the planar coil due to vibration.

[0011] (4) In the magnetic coil of the above embodiment, the third magnetic layer may be disposed so as to be in contact with an area of ​​at least one of the first surface and the second surface corresponding to the planar coil, which also makes it possible to suppress cracks in the first magnetic layer or the second magnetic layer and peeling from the planar coil due to vibration.

[0012] (5) In the magnetic coil of the above aspect, the coil layer may include a fourth magnetic layer, which is disposed on at least a portion of the side surface of the wire of the planar coil in the magnetic portion made of the magnetic composite material and has a content of the magnetic particles lower than that of the remaining region of the magnetic portion. With this configuration, it is possible to further suppress peeling between the magnetic portion and the planar coil.

[0013] (6) According to another aspect of the present disclosure, there is provided a magnetic member. The magnetic member includes the magnetic coil according to any one of the above aspects. The magnetic coil according to the above aspect prevents separation between the coil and the portion made of the magnetic composite material, thereby improving the vibration resistance of the magnetic member and preventing an increase in AC resistance in the magnetic member.

[0014] (7) According to yet another aspect of the present disclosure, there is provided a wireless power supply device. The wireless power supply device includes the magnetic member of the above aspect. Because the wireless power supply device of this aspect includes the magnetic member of the above aspect, it is possible to improve the vibration resistance of the wireless power supply device and suppress a decrease in power transmission efficiency.

[0015] The present disclosure can be realized in various forms other than those described above, such as a method for manufacturing a magnetic coil, a wireless power supply method using a magnetic coil, a vehicle using a magnetic coil, a moving body using a magnetic coil, etc. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is an explanatory diagram conceptually showing the planar configuration of a magnetic coil according to the first embodiment. [Figure 2] FIG. 2 is an explanatory diagram conceptually showing a cross-sectional configuration of a magnetic coil. [Figure 3] FIG. 2 is an explanatory diagram conceptually showing an enlarged cross-sectional configuration of a magnetic coil. [Figure 4] FIG. 3 is an explanatory diagram conceptually showing a first surface of a coil layer. [Figure 5] 3 is an explanatory diagram illustrating an enlarged schematic view of a first surface of the coil layer. FIG. [Figure 6] FIG. 1 is an explanatory diagram illustrating a schematic configuration of a magnetic composite material. [Figure 7] 1 is a cross-sectional schematic diagram illustrating a magnetic composite material including soft magnetic particles having a spherical particle shape. [Figure 8] 1 is a cross-sectional view showing a magnetic composite material including soft magnetic particles having a flat particle shape. FIG. [Figure 9] 10A to 10C are explanatory diagrams showing an example of a method for manufacturing a magnetic coil. [Figure 10] 1 is an explanatory diagram illustrating a schematic configuration of a wireless power supply system including a magnetic member including a magnetic coil. [Figure 11] FIG. 2 is an explanatory diagram schematically illustrating the arrangement of magnetic coils. [Figure 12] 10A and 10B are cross-sectional views illustrating the operation of wireless power supply; [Figure 13] FIG. 10 is an explanatory diagram conceptually showing a cross-sectional configuration of a magnetic coil according to a second embodiment. [Figure 14] FIG. 10 is a diagram showing an SEM image of a cross section of a magnetic coil. [Figure 15] 10A to 10C are explanatory diagrams showing an example of a method for manufacturing a magnetic coil. [Figure 16] FIG. 10 is an explanatory diagram conceptually showing a cross-sectional configuration of a magnetic coil according to a third embodiment. [Figure 17] FIG. 10 is an explanatory diagram conceptually showing a cross-sectional configuration of a magnetic coil according to a fourth embodiment. [Figure 18] FIG. 10 is an explanatory diagram conceptually showing a cross-sectional configuration of a magnetic coil according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] <First embodiment> A. Magnetic coil configuration: FIG. 1 is an explanatory diagram conceptually illustrating the planar configuration of a magnetic coil 41 according to a first embodiment of the present disclosure. The drawing shows mutually orthogonal X, Y, and Z axes for identifying directions. For convenience, the positive Z-axis direction is referred to as the upward direction, and the negative Z-axis direction is referred to as the downward direction. As shown in the figure, the magnetic coil 41 includes a planar coil 42 formed by spirally wound wire material 42L, and a magnetic composite material 10. The planar coil 42 is a plate-shaped coil made of a metal such as aluminum or copper. The cross-sectional shape of the wire material 42L of the planar coil 42 is substantially rectangular. The use of a planar coil (also referred to as a plate-shaped coil) can contribute to weight reduction, thinning, high power transmission efficiency, and reduced AC resistance of the coil. The magnetic composite material 10 includes a resin material 12 and soft magnetic particles 14 (described in detail below).

[0018] FIG. 2 is an explanatory diagram conceptually illustrating the cross-sectional configuration of the magnetic coil 41. FIG. 2 shows the AA cross section in FIG. 1. As shown in the figure, the magnetic coil 41 has a first magnetic layer 45 disposed on a coil layer 43 and a second magnetic layer 47 disposed below the coil layer 43. The coil layer 43 includes a planar coil 42 and a magnetic composite material 10. The planar coil 42 is flat and has a first coil surface SC1 and a second coil surface SC2 that is the back surface of the first coil surface SC1. The coil layer 43 has a first surface S1 that includes the first coil surface SC1 of the planar coil 42 and a second surface that includes the second coil surface SC2 of the planar coil 42. The first magnetic layer 45 is made of the magnetic composite material 10 and is disposed on the first surface S1 of the coil layer 43. The second magnetic layer 47 is made of the magnetic composite material 10 and is disposed on the second surface S2 of the coil layer 43.

[0019] FIG. 3 is an explanatory diagram conceptually illustrating an enlarged cross-sectional configuration of the magnetic coil 41. FIG. 3 illustrates an enlarged view of the X portion in FIG. 2. The first magnetic layer 45 includes a third magnetic layer 48 on the coil layer 43 side, the third magnetic layer 48 having a content of soft magnetic particles 14 less than that of the remaining region, and the third magnetic layer 48 contacts the entire first surface S1 of the coil layer 43. The second magnetic layer 47 includes a third magnetic layer 48 on the coil layer 43 side, the third magnetic layer 48 having a content of soft magnetic particles 14 less than that of the remaining region, and the third magnetic layer 48 contacts the entire second surface S2 of the coil layer 43. In this embodiment, the third magnetic layer 48 does not contain soft magnetic particles 14.

[0020] In the magnetic coil 41, the third magnetic layer 48 can be identified by observing the cross section with an electron microscope. After processing the cross section with a Cross Section Polisher (registered trademark) (CP), the cross section is observed with a scanning electron microscope. The Cross Section Polisher (registered trademark) (CP) processing may be performed while cooling. In the scanning electron microscope observation, observation using a backscattered electron image is more preferable because it allows for clear observation of differences in elements and materials.

[0021] The coil layer 43 has a magnetic portion 432 made of the magnetic composite material 10 and a planar coil 42. As shown in Fig. 3, in the coil layer 43, the magnetic portion 432 is formed by filling the magnetic composite material 10 between adjacent wires 42L. If the magnetic composite material 10 is not filled between the adjacent wires 42L and air is present, the state of the magnetic field may change and the magnetic field may leak. However, in this configuration, the leakage of the magnetic field can be suppressed, and a decrease in power transmission efficiency can be suppressed.

[0022] FIG. 4 is an explanatory diagram conceptually showing the first surface S1 of the coil layer 43. FIG. 5 is an explanatory diagram schematically showing an enlarged view of the first surface S1 of the coil layer 43. The first surface S1 has a region R42 corresponding to the planar coil and a region R432 corresponding to the magnetic portion. As shown enlarged in FIG. 5, the magnetic portion 432 is disposed between adjacent wire rods 42L, and a region R432 is located between adjacent regions R42 on the first surface S1. The second surface S2 of the coil layer 43 similarly has a region R42 and a region R432.

[0023] As described above, in the magnetic coil 41 of this embodiment, the third magnetic layer 48 of the first magnetic layer 45 contacts the entire surface of the first surface S1 of the coil layer 43, and the third magnetic layer 48 of the second magnetic layer 47 contacts the entire surface of the second surface S2 of the coil layer 43. That is, the third magnetic layer 48 of the first magnetic layer 45 contacts the region R42 and the region R432 of the first surface S1 of the coil layer 43. The third magnetic layer 48 of the second magnetic layer 47 contacts the region R42 and the region R432 of the second surface S2 of the coil layer 43.

[0024] The boundary between the planar coil 42 and the magnetic composite material 10 is prone to cracking and peeling due to vibration. According to the magnetic coil 41 of this embodiment, the third magnetic layer 48, which contains a smaller amount of soft magnetic particles 14 than the remaining region, contacts the first surface S1 and the second surface S2 of the coil layer 43. The third magnetic layer 48 contains a smaller amount of soft magnetic particles 14 than the remaining region, is highly flexible, and is less likely to become a fracture starting point. Therefore, by providing the third magnetic layer 48 in contact with the first surface S1 and the second surface S2 of the coil layer 43, which are prone to cracking and peeling, cracking can be suppressed in the first magnetic layer 45 and the second magnetic layer 47, and peeling between the planar coil 42 and the first magnetic layer 45 and the second magnetic layer 47 can be suppressed. In other words, the vibration resistance of the magnetic coil 41 can be improved.

[0025] B. Composition of magnetic composite material: FIG. 6 is an explanatory diagram showing a schematic configuration of a magnetic composite material 10. The magnetic composite material 10 includes a resin material 12 and soft magnetic particles 14 contained in the resin material 12. In the magnetic composite material 10 of this embodiment, the soft magnetic particles 14 are dispersed in the resin material 12 in the form of powder particles. As will be described later, the magnetic composite material 10 of this embodiment is characterized in that it is particularly excellent in vibration resistance (impact resistance). Below, the overall configuration of the magnetic composite material 10 will first be described.

[0026] The resin material 12 preferably has vibration-absorbing properties by itself, and examples thereof include elastomers such as natural rubber, butyl rubber, nitrile rubber, silicone rubber, polyurethane, and fluorine-based rubber. Among these, silicone rubber is particularly preferred due to its ease of mixing with the soft magnetic particles 14 (filler) and its high heat resistance, weather resistance, and adhesive properties. When silicone rubber is used as the resin material 12, the molecular weight between crosslinking points of the silicone rubber is preferably 20,000 or more in order to optimize the elongation and rubber hardness of the magnetic composite material 10. Using an elastomer as the resin material 12 can improve flexibility compared to using polycarbonate, polypropylene, epoxy resin, or phenolic resin. Furthermore, it can improve heat resistance and weather resistance compared to urethane. Resin materials other than elastomers may also be used as the resin material 12. For example, using polycarbonate or polypropylene can result in a magnetic composite material 10 with excellent shape stability, using urethane can result in a magnetic composite material 10 with excellent vibration absorption ability, and using epoxy resin or phenolic resin can result in a magnetic composite material 10 with excellent adhesiveness.

[0027] The soft magnetic particles 14 are preferably practical as a magnetic material in a frequency range of, for example, 50 to 100 kHz. This allows the magnetic composite material 10 to be suitably used in wireless power supply devices, as described below. The frequency range of 50 to 100 kHz is a frequency range in which high power transmission efficiency can be achieved in wireless power supply. From the perspective of applying the magnetic composite material 10 to a wireless power supply device, it is desirable that the soft magnetic particles 14 function well as a magnetic material, particularly in the 85 kHz band, which is the resonance frequency of magnetic field coupling type wireless power supply. The soft magnetic particles 14 can include, for example, at least one of a soft magnetic metal and a soft magnetic ferrite. The inclusion of such soft magnetic particles 14 allows the magnetic composite material 10 to function as a good magnetic material.

[0028] Examples of soft magnetic metals constituting the soft magnetic particles 14 include Fe-Si alloys, Fe-Si-Cr alloys, sendust (Fe-Si-Al alloys), and permalloy (Fe-Ni alloys). Examples of ferrites constituting the soft magnetic particles 14 include Ni-Zn ferrite (nickel zinc ferrite) and Mn-Zn ferrite (manganese zinc ferrite). Among these soft magnetic materials, Ni-Zn ferrite and Mn-Zn ferrite are particularly preferred because they have a large real part μ' of the complex relative permeability in the frequency range of 50 kHz to 100 kHz. The larger the real part μ' of the complex relative permeability, the greater the degree to which magnetic flux can be confined.

[0029] Furthermore, the shape of the powder particles that are the soft magnetic particles 14 is preferably close to spherical, from the viewpoint of improving the vibration absorption properties of the entire magnetic composite material 10. Specifically, the aspect ratio (major axis / minor axis) of the powder particles of the soft magnetic particles 14 is preferably, for example, 5 or less, and more preferably 3 or less. Here, the "major axis" refers to the maximum value of the distance between two parallel lines when an image of a powder particle of the soft magnetic particles 14 projected in the vertical direction is sandwiched between the two lines, and the "minor axis" refers to the minimum value of the distance between the two lines. The effect of the particle shape of the soft magnetic particles 14 on the vibration and shock absorption by the magnetic composite material 10 will be further described below.

[0030] FIG. 7 is a cross-sectional schematic diagram of a magnetic composite material 10a including spherical soft magnetic particles 14a, and FIG. 8 is a cross-sectional schematic diagram of a magnetic composite material 10b including flat soft magnetic particles 14b. FIGS. 7 and 8 show an object 20 colliding with a sheet of each magnetic composite material, applying an impact to the magnetic composite material. Generally, when an impact is applied to a sheet made of an elastomer, the impact is absorbed by the deformation of the elastomer. As shown in FIGS. 7 and 8, when an impact is applied to a sheet made of a magnetic composite material containing both an elastomer and a soft magnetic substance (filler), the impact is absorbed by the rearrangement of the filler and the deformation of the resin material 12 present between the filler. After the impact, the sheet made of the magnetic composite material attempts to return to its original shape.

[0031] Here, when the filler has a nearly spherical shape as shown in Fig. 7, the filler that receives an impact can disperse the impact to other adjacent fillers, and as a result, the amount of deformation of the resin material 12 around these fillers also increases, making it easier to absorb a larger impact. In Fig. 3, the dashed arrows indicate how the impact is dispersed from the impacted filler to the surrounding fillers.

[0032] In contrast, when the filler has a flat shape, as shown in Figure 8, the filler behaves like a metal or ceramic plate when subjected to impact. In Figure 8, the outline arrows indicate how the impact is transmitted within the magnetic composite material 10b. When the filler has a flat shape, the resin material 12 undergoes minimal deformation in response to the impact, and some of the impact is converted into a repulsive force, which remains as residual stress within the sheet made of the magnetic composite material. Therefore, to improve the impact resistance (vibration resistance) of the magnetic composite material 10, it is preferable that the particle shape of the soft magnetic particles 14 be closer to spherical. As mentioned above, the degree to which an impact is converted into a repulsive force and the degree to which it remains as residual stress within the magnetic sheet increases with the storage modulus of the magnetic sheet. Therefore, even when flat-shaped soft magnetic particles 14 are used as the filler, reducing the storage modulus of the magnetic sheet can ensure the impact resistance and vibration resistance of the magnetic sheet.

[0033] When the soft magnetic particles 14 are made of metal and have a particle shape close to a sphere, the particle size of the soft magnetic particles 14 is preferably 10 μm or more from the viewpoint of increasing the real part μ' of the complex relative magnetic permeability. Then, from the viewpoint of shifting the peak of the imaginary part μ" of the complex relative magnetic permeability of the magnetic composite material 10 described later to the higher frequency side, the particle size of the soft magnetic particles 14 is preferably 50 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less. Furthermore, when the soft magnetic particles 14 have a flat shape and, for example, an aspect ratio of more than 5, for the same reasons as when the particle shape is spherical, the long side of the powder particle of the soft magnetic particles 14 is preferably 20 μm or more, and the short side is preferably 1 μm or more. Then, the long side of the powder particle of the soft magnetic particles 14 is preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 80 μm or less. Furthermore, the short side of the powder particle of the soft magnetic particles 14 is Preferably, the particle size is 10 μm or less, more preferably 9 μm or less, and even more preferably 8 μm or less. When the soft magnetic particles 14 have a flat shape, the powder particles of the soft magnetic particles 14 are oriented in the resin material 12. Therefore, in addition to ensuring the impact resistance (vibration resistance) described above, it is also preferable that the powder particles of the soft magnetic particles 14 have a particle shape close to spherical, from the viewpoint of ensuring the flexibility of the magnetic sheet. When the soft magnetic particles 14 are made of ferrite, unlike when the soft magnetic particles 14 are made of metal, there is no preferred particle size range for the soft magnetic particles 14 from the viewpoint of increasing the real part μ' of the complex relative permeability due to the high electrical resistance of ferrite. The particle size may be set to be smaller than the thickness of the member formed from the magnetic composite material 10.

[0034] Furthermore, the loss factor tan δ of magnetic composite material 10, measured by dynamic viscoelasticity measurement at room temperature in a frequency range of 1 Hz to 110 Hz (hereinafter simply referred to as "loss factor tan δ"), may be 0.05 or greater, and preferably 0.1 or greater. The value of the loss factor tan δ of magnetic composite material 10 can be expressed as, for example, the degree to which impact energy can be converted into other energy, and it can be said that the larger the loss factor tan δ, the higher the impact absorption ability of magnetic composite material 10. Therefore, by setting the value of the loss factor tan δ of magnetic composite material 10 within the above range, it is possible to prevent damage to magnetic composite material 10 and damage to electronic devices and the like adjacent to magnetic composite material 10 caused by damage to magnetic composite material 10 when vibrations of a frequency range of about 1 Hz to 110 Hz are applied.

[0035] In the magnetic composite material 10, the real part μ' of the complex relative magnetic permeability in the frequency range of 50 kHz to 100 kHz (hereinafter simply referred to as the "real part μ'") may be 5 or greater, more preferably 10 or greater, and even more preferably 20 or greater. It is particularly preferable that the real part μ' be constant around 85 kHz, which is the resonant frequency of magnetic field coupling-based wireless power transfer. This makes it possible to compensate for frequency fluctuations to a certain extent. The real part μ' of the complex relative magnetic permeability represents the performance of a magnetic material; the larger the real part μ', the stronger the magnetic field it can retain. By setting the real part μ' in the above range, the magnetic composite material 10 can function well as a magnetic material in the above frequency band and can confine magnetic flux. The value of this real part μ' can be adjusted by the type of soft magnetic material constituting the soft magnetic particles 14, and can be increased by increasing the particle size of the soft magnetic particles 14 or by increasing the amount of soft magnetic particles 14 added to the magnetic composite material 10. Furthermore, when flattened soft magnetic particles 14 are used in a sheet made of magnetic composite material 10, the soft magnetic particles 14 are oriented so that the major axis of the flattened shape approaches parallel to the sheet surface, thereby increasing the real part μ' of magnetic composite material 10 in the plane parallel to the sheet surface. Furthermore, reducing the particle size of soft magnetic particles 14 makes it possible to maintain a high value of real part μ' even in higher frequency bands.

[0036] In magnetic composite material 10, the storage modulus (hereinafter simply referred to as "storage modulus") measured by dynamic viscoelasticity measurement at room temperature in a frequency range of 1 Hz to 110 Hz is preferably 200 MPa or less, more preferably 100 MPa or less, and even more preferably 50 MPa or less. The storage modulus is a parameter that indicates the hardness that contributes to the shock absorption capacity of magnetic composite material 10, which is a viscoelastic body. To ensure the shock absorption capacity of magnetic composite material 10, a lower storage modulus is desirable. In other words, the lower the storage modulus, the more flexible magnetic composite material 10 is, and the more difficult it is for magnetic composite material 10 to preserve (storage) energy in response to displacement. Furthermore, since the energy stored in magnetic composite material 10 leads to repulsion energy in response to impact, a lower storage modulus can be said to enhance the shock absorption capacity of magnetic composite material 10.

[0037] It is desirable that the magnetic composite material 10 has an elongation rate (hereinafter simply referred to as "elongation rate") of 30% or more at room temperature. This ensures the flexibility of the magnetic composite material 10. By ensuring the flexibility and deformability of the magnetic composite material 10, for example, when the magnetic composite material 10 is used integrated with a member having a large thermal expansion coefficient, such as a metal member (for example, when the magnetic composite material 10 is integrated with a coil to form a magnetic member as described below), the magnetic composite material 10 can easily follow the thermal expansion of the metal member when the temperature rises.

[0038] In the magnetic composite material 10, the rubber hardness (hereinafter simply referred to as "rubber hardness") measured with a Type A durometer specified in JIS K 6235-3:2012 is preferably 80 or less, more preferably 70 or less, and even more preferably 60 or less. The rubber hardness is one of the parameters that indicates the hardness that contributes to the shock absorption ability of the magnetic composite material 10, which is an elastic body. The lower the rubber hardness, the more flexibly the magnetic composite material 10 can deform in response to an impact, so a lower rubber hardness is desirable in order to ensure the shock absorption ability of the magnetic composite material 10. However, if the rubber hardness of the magnetic composite material 10 is excessively low, the magnetic composite material 10 may lack strength, so the rubber hardness is preferably 10 or more.

[0039] The loss factor tanδ, storage modulus, rubber hardness, elongation, and shear bond strain of the magnetic composite material 10 described above can be adjusted, for example, by the crosslink density of the resin material 12, the molecular weight of the resin material 12, the amount of soft magnetic particles 14 added to the magnetic composite material 10, and the particle shape of the soft magnetic particles 14. For example, lowering the crosslink density of the resin material 12 tends to increase the loss factor tanδ, elongation, and shear bond strain, and tend to decrease the storage modulus and rubber hardness. Increasing the molecular weight between crosslink points of the resin material 12 tends to increase the loss factor tanδ, elongation, and shear bond strain, and tend to decrease the storage modulus and rubber hardness. In addition, reducing the amount of soft magnetic particles 14 added to the magnetic composite material 10 tends to increase the loss factor tanδ, elongation, and shear bond strain, and tend to decrease the storage modulus and rubber hardness. However, reducing the amount of soft magnetic particles 14 added to magnetic composite material 10 reduces the magnetic properties of magnetic composite material 10, and therefore, reducing the amount of soft magnetic particles 14 added is undesirable from the perspective of ensuring the magnetic properties of magnetic composite material 10. Furthermore, the closer the particle shape of soft magnetic particles 14 is to a sphere, the greater the loss factor tan δ, elongation, and shear adhesive strain tend to be, and the greater the storage modulus and rubber hardness tend to be.

[0040] In the magnetic composite material 10, the imaginary part μ" of the complex relative permeability in the frequency range of 50 kHz to 100 kHz (hereinafter also referred to simply as "imaginary part μ") is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less. In this way, by suppressing the imaginary part μ" of the complex relative permeability, it is possible to suppress magnetic loss in the magnetic composite material 10. Therefore, for example, when the magnetic composite material 10 is applied to a wireless power supply device as described below and made to function as a transformer component in the frequency range of 50 kHz to 100 kHz, it is possible to increase the power supply efficiency of the wireless power supply device by suppressing magnetic loss.

[0041] In such a magnetic composite material 10, the peak of the imaginary part μ" is desirably 150 kHz or higher. With such a configuration, when a device including the magnetic composite material 10 is used in a frequency range of 50 kHz to 100 kHz, for example, the effect of suppressing magnetic loss of the magnetic composite material 10 can be enhanced. The peak of the imaginary part μ" can be shifted to the higher frequency side by reducing the particle size of the soft magnetic particles 14 or by covering the powder particles of the soft magnetic particles 14 with a resin. In addition, increasing the degree of dispersion of the powder particles of the soft magnetic particles 14 in the magnetic composite material 10 can also contribute to the shift of the peak of the imaginary part μ". The imaginary part μ" of the complex relative permeability represents loss, and is small near 85 kHz, which is the resonance frequency of magnetic field coupling wireless power transfer, and it is preferable that the peak position is shifted from 85 kHz. This is because the presence of an imaginary component reduces the magnetic flux.

[0042] The magnetic composite material 10 preferably has a shear adhesive strain of 20% or more, and more preferably 30% or more, relative to the aluminum plate. The larger the shear adhesive strain, the stronger the adhesiveness of the magnetic composite material 10 to the aluminum plate. As shown in FIG. 1, when the magnetic composite material 10 is used to form a magnetic coil 41, the adhesiveness with a planar coil 42 containing aluminum as a main component can be ensured. The shear adhesive strain can be increased by using, for example, adhesive silicone rubber as the resin material 12.

[0043] The magnetic composite material 10 of this embodiment configured as described above has a loss factor tanδ of 0.05 or greater as determined by dynamic viscoelasticity measurement at room temperature in the frequency range of 1 Hz to 110 Hz. This ensures the shock absorption capability of the magnetic coil 41 containing the magnetic composite material 10 when vibrations of approximately 1 Hz to 110 Hz are applied to the magnetic coil 41. This prevents damage to components made of the magnetic composite material 10 due to vibration shock, and prevents damage to electronic devices and other devices adjacent to the magnetic coil 41 containing the magnetic composite material 10 due to damage to the magnetic coil 41. Furthermore, the magnetic composite material 10 of this embodiment has a high real part μ' of complex relative permeability of 5 or greater in the frequency range of 50 kHz to 100 kHz, thereby improving the degree to which the magnetic composite material 10 can retain a magnetic field. For example, when a coil is coated with this magnetic composite material 10, the magnetic field can be confined around the coil without being eliminated in the frequency range of 50 kHz to 100 kHz.

[0044] C.Magnetic coil manufacturing method: 9 is an explanatory view showing an example of a manufacturing method for the magnetic coil 41 of this embodiment. Fig. 9 shows a cross section corresponding to Fig. 3 at step P116, which will be described later. In this manufacturing method, the following steps P102 to P118 are performed in order. (Step P102) A magnetic powder made of metal and a thermosetting resin are mixed to prepare a paste-like magnetic composite material 102. (Step P104) A magnetic composite material 104 containing a small amount of magnetic powder is prepared. (Step P106) The magnetic composite material 102 is spread to a predetermined thickness. (Step P108) The magnetic composite material 104 is spread on the spread magnetic composite material 102. (Step P110) The coil 42 is placed. (Step P112) The magnetic composite material 102 is applied between the coils 42, filling the gaps between the coils 42 so that no air bubbles remain. (Step P114) Then, a thin layer of magnetic composite material 104 is applied. (Step P116) Then, the magnetic composite material 102 is applied to a predetermined thickness. (Step P118) By heating and curing, the coil coated with the magnetic composite material is completed. According to this method for manufacturing a magnetic coil, the magnetic coil 41 of this embodiment can be easily manufactured.

[0045] D: Wireless power supply system configuration: The magnetic coil 41 of this embodiment can be suitably used as a component of a wireless power supply system, for example. A wireless power supply system including a magnetic member including the magnetic coil 41 will be described below.

[0046] Fig. 10 is an explanatory diagram schematically illustrating the configuration of a wireless power feeding system 30 including a magnetic member including a magnetic coil 41. The wireless power feeding system 30 shown in Fig. 10 is a system that feeds power wirelessly by electromagnetic induction, and includes a wireless power feeding device 40 on the power receiving side and a wireless power feeding device 50 on the power transmitting side.

[0047] The wireless power transfer device 40 includes a magnetic member 58 having a magnetic coil 41 and a magnetic sheet 18, a circuit board 44, and a load 46. The magnetic coil 41 includes a planar coil 42 as a secondary coil on the power receiving side, and a magnetic composite material 10 covering the planar coil 42. The magnetic sheet 18 is a sheet that functions as a good magnetic material, and may be, for example, a metal sheet made of a soft magnetic metal or a ferrite sheet made of soft magnetic ferrite. In the example shown in FIG. 10 , the planar coil 42 is covered by the magnetic composite material 10 and is disposed on the back side of the magnetic sheet 18, with the portion hidden by the magnetic sheet 18 indicated by dashed lines. The circuit board 44 is electrically connected to the planar coil 42 and is provided to supply power generated by the planar coil 42 to the load 46. FIG. 10 shows, as an example, the wireless power transfer device 40 mounted on a vehicle (electric vehicle) 60. Vehicle 60 includes wireless power supply device 40 and a power storage device that stores power for driving vehicle 60. The power storage device corresponds to load 46 in FIG. 10 , and power generated in planar coil 42 is supplied to the power storage device via circuit board 44. Circuit board 44 includes a converter that converts the voltage when power is supplied from planar coil 42 to the power storage device into a voltage suitable for charging the power storage device. Note that, although load 46 in vehicle 60 is the power storage device, load 46 may also include a vehicle drive motor, allowing power to be directly supplied to the drive motor from wireless power supply device 40.

[0048] The wireless power supply device 50 includes a magnetic member 59 having a magnetic coil 51 and a magnetic sheet 18, a circuit board 54, and a load 56. The magnetic coil 51 includes a planar coil 52 as a primary coil on the power transmission side, and a magnetic composite material 10 covering the planar coil 52. In the example shown in FIG. 10 , the planar coil 52 is covered with the magnetic composite material 10, and the portion hidden by the magnetic composite material 10 is indicated by a dashed line. In the wireless power supply device 50, the magnetic coil 51 is disposed on the magnetic sheet 18. The circuit board 54 is electrically connected to the planar coil 52 and is provided to supply AC power to the planar coil 52. For example, as shown in FIG. 10 , when the power receiving wireless power supply device 40 is mounted on a vehicle 60, the wireless power supply device 50 may be installed at a specific location provided for power supply so as to be able to supply power to the vehicle 60 parked at the specific location. The circuit board 54 includes a converter that converts the voltage when power is supplied from the power supply device 56 to the planar coil 52 into a voltage suitable for power supply operation using the planar coil 52, and an inverter.

[0049] Fig. 11 is an explanatory diagram that schematically shows the arrangement of the magnetic coil 41 and the magnetic coil 51. Fig. 11 shows a cross section perpendicular to the plane direction of the magnetic coil 41 and the magnetic coil 51. As shown in the figure, the magnetic coil 41 and the magnetic coil 51 are arranged facing each other, and magnetic sheets 18 are arranged on the outside of the magnetic coil 41 and the magnetic coil 51, respectively.

[0050] FIG. 12 is a cross-sectional view illustrating the operation of wireless power feeding using a wireless power feeding system 30 including a wireless power feeding device 40 on the power receiving side and a wireless power feeding device 50 on the power transmitting side. FIG. 12 shows an enlarged view of a part of a cross section perpendicular to the plane direction of the magnetic coil 41 and the magnetic coil 51, corresponding to FIG. 3. In FIG. 12, the state of the magnetic flux during electromagnetic induction is indicated by a broken line as magnetic flux 32. Also, in FIG. 12, the direction of the magnetic field lines is indicated by arrows. As shown in the figure, in the magnetic coil 41, the magnetic composite material 10 is filled between adjacent wire rods 42L of the planar coil 42. Similarly, in the magnetic coil 51, the magnetic composite material 10 is filled between adjacent wire rods 52L of the planar coil 52. Because the magnetic composite material 10 contains soft magnetic particles, when electromagnetic induction is performed using the primary coil (planar coil 52) and secondary coil (planar coil 42) arranged opposite each other, the magnetic field from the coil can be suppressed from spreading, and the magnetic fields generated between adjacent wires can be prevented from canceling each other out (proximity effect), which results in reduced AC resistance and improved power transmission efficiency.

[0051] Since the real part μ' of the complex relative permeability of the magnetic composite material 10 used in the magnetic coil 41 of this embodiment is 5 or more, by covering the coil with the magnetic composite material 10, the magnetic field can be confined around the coil without being eliminated.

[0052] Furthermore, when electromagnetic induction is performed using a primary coil and a secondary coil arranged opposite to each other, magnetic flux spreads to the outside of the primary coil and the secondary coil if they are not covered with magnetic composite material 10. However, by covering each of planar coil 52 and planar coil 42 with magnetic composite material 10 as shown in Fig. 12, the magnetic flux can be converged and confined around planar coil 52 and planar coil 42, thereby ensuring high power supply efficiency.

[0053] As described above, the magnetic flux converging performance can be improved by reducing the value of the imaginary part μ" of the complex relative permeability of the magnetic composite material 10. For example, when a magnetic sheet made of a magnetic composite material comprising a soft magnetic material and an elastomer is used as a radio wave absorber, the value of the imaginary part μ" can be increased in the frequency band used to increase magnetic loss and release the radio wave energy as heat, thereby improving the performance as a radio wave absorber. Therefore, the properties of the magnetic composite material 10 of this embodiment, in which the value of the imaginary part μ" is reduced, can be said to be characteristics specific to magnetic materials that are suitable for converging magnetic flux, as described above.

[0054] Furthermore, because the magnetic composite material 10 including the soft magnetic particles 14 has excellent magnetic shielding properties, it is possible to prevent the relatively high-frequency magnetic flux transmitted from the planar coil 52 in the wireless power supply device 40 from penetrating the magnetic composite material 10. Therefore, when the wireless power supply device 40 includes, for example, a metal housing that houses the magnetic coil 41, it is possible to prevent the magnetic flux transmitted from the planar coil 52 from reaching the housing. This prevents a decrease in power transmission efficiency and excessive heat generation due to eddy currents generated in the metal housing by the magnetic flux that has reached the housing.

[0055] As described above, by configuring the wireless power supply system 30 using the magnetic composite material 10, the vibration resistance of the wireless power supply device 40 or the wireless power supply device 50 can be improved, and damage to the magnetic composite material 10 can be suppressed even when the wireless power supply device 40 or the wireless power supply device 50 is subjected to an impact. Here, the frequency of vibrations when an automobile is running is generally considered to be approximately several Hz to 200 Hz. Therefore, by setting the loss factor tan δ of the magnetic composite material 10 to the above-described value as determined by dynamic viscoelasticity measurement at room temperature in a frequency range of 1 Hz to 110 Hz, when the magnetic coil 41 covered by the magnetic composite material 10 is mounted on and used in a vehicle as described above, the vibration absorption performance of the magnetic composite material 10 can be ensured, and damage to the magnetic coil 41 caused by vibration can be suppressed. Furthermore, by including the magnetic composite material 10 with excellent vibration resistance in the wireless power supply device 50 on the power transmission side, damage to the magnetic coil 51 caused by vibration can be suppressed even when an impact is applied due to vibrations, for example, when a vehicle enters or exits the vehicle for power supply.

[0056] The magnetic coil 41 of the above-described embodiment may be used for purposes other than wireless power supply devices for electric vehicles. For example, it may be used in wireless power supply devices provided in aircraft, satellites, smartphones, tablet terminals, small home appliances, etc. When used in wireless power supply devices provided in equipment that is subjected to vibrations similar to electric vehicles, the magnetic coil 41 can achieve the same effects due to its excellent vibration resistance.

[0057] <Second embodiment> FIG. 13 is an explanatory diagram conceptually showing the cross-sectional configuration of a magnetic coil 41A of the second embodiment. FIG. 13 is a diagram corresponding to FIG. 3 in the first embodiment. FIG. 14 is a diagram showing an SEM (scanning electron microscope) image of a cross section of the magnetic coil 41A. The magnetic coil 41A of the second embodiment differs from the magnetic coil 41 of the first embodiment in the arrangement of the third magnetic layer 48, but the other configurations are similar to those of the first embodiment. In the following embodiments, the same components as those of the first embodiment are denoted by the same reference numerals, and the preceding description is referred to.

[0058] 13 and 14, in the magnetic coil 41A of this embodiment, the third magnetic layer 48 is arranged so as to be in contact with a region R432 corresponding to the magnetic portion of the first surface S1 of the coil layer 43. The third magnetic layer 48 is also arranged so as to be in contact with a region R432 corresponding to the magnetic portion of the second surface S2 of the coil layer 43.

[0059] The corners of the wire 42L are prone to stress concentration due to vibration and temperature changes, making them prone to fracture initiation points. As mentioned above, the third magnetic layer 48 is highly flexible. When it is positioned in contact with the corners of the wire 42L as shown in the figure, stress concentration at the corners of the wire 42L makes them less likely to become fracture initiation points, thereby preventing peeling. The cross section was cooled and processed with a Cross-Section Polisher (registered trademark) (CP), and then carbon was vapor-deposited to prevent static buildup. Then, the cross section was observed and photographed using a field emission scanning electron microscope (FE-SEM). The FE-SEM imaging conditions were as follows: Backscattered electron images were obtained at 60x and 300x magnifications at an accelerating voltage of 5.0 kV. The actual size can be measured by comparing with the scale at the bottom of the photograph in Figure 14. Known field emission scanning electron microscopes, such as the JSM-IT710HR manufactured by JEOL Ltd. or the SU5000 manufactured by Hitachi, Ltd., can be used.

[0060] 15 is an explanatory diagram showing an example of a manufacturing method for the magnetic coil 41A of this embodiment. In this manufacturing method, the following steps P202 to P210 are performed in order. (Step P202) Metallic magnetic powder and thermosetting resin are mixed to create a paste-like magnetic composite material. A portion of the magnetic composite material is spread to a predetermined thickness and then gently heated and cured to create a semi-cured sheet 47S of magnetic composite material. This gentle heat-curing process forms a layer that will become the third magnetic layer after magnetic coil 41A is completed, with a magnetic particle content lower than the remaining region. (Step P204) The planar coil 42 is placed on the semi-hardened sheet 47S. (Step P206) Magnetic composite material 43P is applied between planar coils 42, filling the gaps between planar coils 42 so that no air bubbles remain. (Process P208) The semi-hardened sheet 45S is attached from above and pressed to push out excess magnetic composite material and flatten it. (Step P210) The magnetic coil 41A is completed by heat curing. According to this method for manufacturing a magnetic coil, the magnetic coil 41A of this embodiment can be easily manufactured.

[0061] <Third embodiment> Fig. 16 is an explanatory diagram conceptually showing the cross-sectional configuration of a magnetic coil 41B of the third embodiment. Fig. 16 is a diagram corresponding to Fig. 3 of the first embodiment. The magnetic coil 41B of the third embodiment differs from the magnetic coil 41 of the first embodiment in the arrangement of the third magnetic layer 48, but the other configurations are similar to those of the first embodiment.

[0062] 16, in the magnetic coil 41B of this embodiment, the third magnetic layer 48 is arranged so as to be in contact with a region R42 corresponding to the planar coil on the first surface S1 of the coil layer 43. The third magnetic layer 48 is also arranged so as to be in contact with a region R42 corresponding to the planar coil on the second surface S2 of the coil layer 43. Even in this manner, the highly flexible third magnetic layer 48 is arranged so as to be in contact with the corners of the wire material 42L, so that even if stress concentrates at the corners of the wire material 42L, the corners are less likely to become fracture starting points, and peeling can be suppressed.

[0063] <Fourth embodiment> Fig. 17 is an explanatory diagram conceptually showing the cross-sectional configuration of a magnetic coil 41C of the fourth embodiment. Fig. 17 is a diagram corresponding to Fig. 3 of the first embodiment. In addition to the configuration of the magnetic coil 41 of the first embodiment, the magnetic coil 41C of the fourth embodiment includes a fourth magnetic layer 49 that is arranged on a side surface SC3 of the wire 42L of the planar coil 42 and has a lower content of soft magnetic particles 14 than the remaining region of the magnetic portion 432. In this embodiment, the fourth magnetic layer 49 does not contain soft magnetic particles 14.

[0064] 17, in the magnetic coil 41C of this embodiment, the fourth magnetic layer 49 is arranged so as to contact the entire side surface SC3 of the wire rod 42L of the planar coil 42. The fourth magnetic layer 49 has high flexibility, similar to the third magnetic layer 48. Therefore, in this manner, the wire rod 42L is covered with the highly flexible third magnetic layer 48 and fourth magnetic layer 49, and the corners of the wire rod 42L are covered with a highly flexible resin, so that even if stress concentrates at the corners of the wire rod 42L, they are less likely to become fracture starting points, and peeling can be suppressed.

[0065] <Fifth embodiment> FIG. 18 is an explanatory diagram conceptually showing the cross-sectional configuration of a magnetic coil 41D of the fifth embodiment. FIG. 18 is a diagram corresponding to FIG. 3 of the first embodiment. The magnetic coil 41D of the fifth embodiment has two coil layers 43 and three magnetic layers. The magnetic layer located in the middle in the Z-axis direction is the second magnetic layer 47 when looking at the upper coil layer 43, and is the first magnetic layer 45 when looking at the lower coil layer 43. This also makes it possible to suppress peeling and cracking between the planar coil 42 and the magnetic composite material 10.

[0066] <Modification of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0067] In the above embodiment, both the first magnetic layer 45 and the second magnetic layer 47 include the third magnetic layer 48. However, it is sufficient that at least one of the first magnetic layer 45 and the second magnetic layer 47 includes the third magnetic layer 48. This also makes it possible to suppress peeling and cracks between the planar coil 42 and the magnetic composite material 10.

[0068] The arrangement of the third magnetic layer 48 is not limited to the above embodiment, and it may be arranged so as to be in contact with at least a portion of the first surface S1 or the second surface S2 of the coil layer 43.

[0069] In the above embodiment, the cross-sectional shape of the wire 42L of the planar coil 42 is rectangular, but the cross-sectional shape of the wire 42L is not limited to a rectangle. For example, the cross-sectional shape of the wire 42L may be a polygon, such as a triangle, pentagon, or hexagon, or may be a polygon, including a rectangle, with rounded corners.

[0070] In the above embodiment, the third magnetic layer 48 and the fourth magnetic layer 49 do not contain soft magnetic particles 14, but it is sufficient if the content of magnetic particles is less than that of the remaining portions of the first magnetic layer 45 and the second magnetic layer 47.

[0071] In the above embodiment, an example including one coil layer 43 and an example including two coil layers 43 are shown, but the number of coil layers 43 is not limited to the above embodiment and may be three or more.

[0072] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0073] The present disclosure can also be realized as the following application examples. [Application example 1] a planar coil and a magnetic coil including a magnetic composite material, The planar coil is The wire is wound in a spiral shape and has a flat plate shape with a first coil surface and a second coil surface that is the back side of the first coil surface, The magnetic composite material comprises: A resin material and magnetic particles contained in the resin material, The magnetic coil is a coil layer having a first surface including the first coil surface of the planar coil and a second surface including the second coil surface of the planar coil; a first magnetic layer made of the magnetic composite material and disposed on the first surface of the coil layer; a second magnetic layer made of the magnetic composite material and disposed on the second surface of the coil layer; Equipped with At least one of the first magnetic layer and the second magnetic layer is a third magnetic layer on the coil layer side, the third magnetic layer having a content of the magnetic particles lower than that of the remaining region; the third magnetic layer is in contact with at least a portion of the first surface or the second surface of the coil layer; Magnetic coil. [Application example 2] The magnetic coil according to Application Example 1, The cross-sectional shape of the wire of the planar coil is substantially rectangular. Magnetic coil. [Application example 3] The magnetic coil according to Application Example 1 or Application Example 2, The coil layer includes: the planar coil; a magnetic portion made of the magnetic composite material; and The third magnetic layer is The magnetic layer is disposed so as to be in contact with a region of the first surface or the second surface corresponding to the magnetic portion. Magnetic coil. [Application example 4] The magnetic coil according to any one of Application Examples 1 to 3, The third magnetic layer is The planar coil is disposed so as to be in contact with a region of at least one of the first surface and the second surface, the region corresponding to the planar coil. Magnetic coil. [Application example 5] The magnetic coil according to any one of Application Examples 1 to 4, The coil layer includes: the magnetic portion made of the magnetic composite material includes a fourth magnetic layer disposed on at least a portion of a side surface of the wire of the planar coil, the fourth magnetic layer having a content of the magnetic particles lower than that of the remaining region of the magnetic portion; Magnetic coil. [Application Example 6] A magnetic member, The magnetic coil according to any one of Application Examples 1 to 5 is provided. Magnetic components. [Application Example 7] A wireless power supply device, The magnetic member according to Application Example 6 is provided. Wireless power supply device. [Explanation of symbols]

[0074] 10,10a,10b,SA...Magnetic composite material 12...Resin material 14,14a,14b...Soft magnetic material 16...Covering part 18...Magnetic sheet 20…object 30...Wireless power supply system 32...Magnetic flux 40,50...Wireless power supply devices 41, 41A, 41B, 41C, 41D, 51...Magnetic coil 42, 52... Planar coil 42L,52L…Wire rod 43...Coil layer 43P, 102, 104...Magnetic composite materials 44, 54...Circuit board 45...First magnetic layer 45S...Semi-hardened sheet 46...Load 47…Second magnetic layer 47S...Semi-hardened sheet 48…Third magnetic layer 49...Fourth magnetic layer 56…Power supply device 60...Vehicle R42,R432…area S1...Side 1 S2...Side 2 SC1: First coil surface SC2: Second coil surface SC3...Side

Claims

1. a planar coil and a magnetic coil including a magnetic composite material, The planar coil is The coil is formed by spirally winding a wire material and has a flat plate shape including a first coil surface and a second coil surface that is the back surface of the first coil surface, The magnetic composite material comprises: A resin material and magnetic particles contained in the resin material, The magnetic coil is a coil layer having a first surface including the first coil surface of the planar coil and a second surface including the second coil surface of the planar coil; a first magnetic layer made of the magnetic composite material and disposed on the first surface of the coil layer; a second magnetic layer made of the magnetic composite material and disposed on the second surface of the coil layer; Equipped with At least one of the first magnetic layer and the second magnetic layer is a third magnetic layer on the coil layer side, the third magnetic layer having a content of the magnetic particles lower than that of the remaining region; the third magnetic layer is in contact with at least a portion of the first surface or the second surface of the coil layer; Magnetic coil.

2. 2. The magnetic coil according to claim 1, The cross-sectional shape of the wire of the planar coil is substantially rectangular. Magnetic coil.

3. 2. The magnetic coil according to claim 1, The coil layer includes: the planar coil; a magnetic portion made of the magnetic composite material; and The third magnetic layer is The magnetic layer is disposed so as to be in contact with a region of the first surface or the second surface corresponding to the magnetic portion. Magnetic coil.

4. 2. The magnetic coil according to claim 1, The third magnetic layer is The planar coil is disposed so as to be in contact with a region of at least one of the first surface and the second surface, the region corresponding to the planar coil. Magnetic coil.

5. 3. The magnetic coil according to claim 2, The coil layer includes: the magnetic portion made of the magnetic composite material includes a fourth magnetic layer disposed on at least a portion of a side surface of the wire of the planar coil, the fourth magnetic layer having a content of the magnetic particles lower than that of the remaining region of the magnetic portion; Magnetic coil.

6. A magnetic member, A magnetic coil according to any one of claims 1 to 5, Magnetic components.

7. A wireless power supply device, The magnetic member according to claim 6 is provided. Wireless power supply device.

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