Coil component, power transmission device, power reception device, power transmission system, and mobile body

Abstract

To provide a coil component capable of realizing an effective power transmission.SOLUTION: A coil component 10 according to an embodiment, comprises: a first flat surface coil 11; a second flat surface coil 12; a holding body 30; and at least one of coated layers 21 to 23. The first flat surface coil 11 includes: a first surface 11a; and a second surface 11b that is opposite to the first surface 11a. The second flat surface coil 12 includes a third surface 12a that is directed to the side of the second surface 11b and a fourth surface 12b to the side opposite to the third surface 12a. The holding body 30 contains a magnetic body. The holding body 30 holds the first flat surface coil 11 and the second flat surface coil 12. At least one of the coated layers 21 to 23 contains a magnetic body. At least one of the coated layers 21 to 23 is contacted to the first surface 11a, the second surface 11b, and / or the third surface 12a. A volume ratio of the magnetic body in the coated layers 21 to 23 is 60% or larger. A thickness of the coated layers 21 to 23 is 0.1 mm or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a coil component, a power transmitting device, a power receiving device, a power transfer system, and a moving body. [Background technology]

[0002] In recent years, wireless power transmission systems that transmit power from a power transmitting device to a power receiving device in a non-contact manner have become widespread. Patent Document 1 discloses a coil component used in a power transmitting device and a power receiving device of a wireless power transmission system. The coil component includes a coil formed in a spiral shape. When power is supplied to the coil of the power transmitting device, a magnetic field is generated in the coil. Due to the effect of this magnetic field, a current flows in the coil of the power receiving device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-27112 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a wireless power transmission system, it is desirable to improve the performance of the coil components to perform efficient power transmission.

[0005] An object of the present disclosure is to provide a coil component, a power transmitting device, a power receiving device, a power transfer system, and a moving body that can realize efficient power transfer. [Means for solving the problem]

[0006] The embodiments of the present disclosure relate to the following [1] to

[17] .

[0007] [1] a first planar coil having a first surface and a second surface opposite the first surface; a second planar coil having a third surface facing the second surface and a fourth surface opposite the third surface; a holder including a magnetic material, at least a portion of which is disposed between the first planar coil and the second planar coil, the holder holding the first planar coil and the second planar coil; At least one coating layer including a magnetic material, the at least one coating layer being disposed between the first surface, the second surface, and / or the third surface and the holder and in contact with the first surface, the second surface, and / or the third surface; Equipped with The volume ratio of the magnetic material in the coating layer is 60% or more, A coil component, wherein the coating layer has a thickness of 0.1 mm or less.

[0008] [2] a first planar coil having a first surface and a second surface opposite the first surface; a second planar coil having a third surface facing the second surface and a fourth surface opposite the third surface; a holder including a magnetic material, at least a portion of which is disposed between the first planar coil and the second planar coil, the holder holding the first planar coil and the second planar coil; At least one coating layer including a magnetic material, the at least one coating layer being disposed between the first surface, the second surface, and / or the third surface and the holder and in contact with the first surface, the second surface, and / or the third surface; Equipped with A coil component, wherein the volume ratio of the magnetic material in the coating layer is 75% or more.

[0009] [3] The coil component according to [1] or [2], wherein a volume ratio of the magnetic body in the coating layer is 100%.

[0010] [4] The coil component according to any one of [1] to [3], wherein a volume ratio of the magnetic body in the covering layer is higher than a volume ratio of the magnetic body in the holding body.

[0011] [5] the holder includes a third layer portion disposed between the second surface and the third surface, The third layer has a thickness of 0.5 mm or more, The coil component described in any one of [1] to [4], wherein the at least one coating layer includes a second coating layer disposed between the third layer portion and the second surface and in contact with the second surface.

[0012] [6] the holder includes a third layer portion disposed between the second surface and the third surface, The third layer has a thickness of 0.5 mm or more, The coil component described in any one of [1] to [5], wherein the at least one coating layer includes a third coating layer disposed between the third layer portion and the third surface and in contact with the third surface.

[0013] [7] the holder includes a first layer portion facing the first surface, The first layer has a thickness of 0.5 mm or more, The coil component described in any one of [1] to [6], wherein the at least one coating layer includes a first coating layer disposed between the first layer portion and the first surface and in contact with the first surface.

[0014] [8] The coil component according to [1] or [2], wherein the coating layer contains magnetic particles and a resin that holds the magnetic particles.

[0015] [9] The coil component according to any one of [1] to [8], wherein the holding body includes magnetic particles and a resin that holds the magnetic particles.

[0016]

[10] the holder has a fifth surface facing the same side as the first surface, The coil component according to any one of [1] to [9], further including a magnetic shield member arranged opposite the first surface and the fifth surface.

[0017]

[11] The coil component according to

[10] , wherein the magnetic shielding member contains ferrite.

[0018]

[12] the holder has a sixth surface facing the same side as the fourth surface, The coil component according to any one of [1] to

[11] , further including a wall portion having magnetism and protruding from the sixth surface.

[0019]

[13] The coil component according to any one of [1] to

[12] , wherein the first planar coil and the second planar coil are plate-shaped.

[0020]

[14] A power transmitting device comprising the coil component according to any one of [1] to

[13] .

[0021]

[15] A power receiving device comprising the coil component according to any one of [1] to

[13] .

[0022]

[16] The power transmission device and the power receiving device are provided. A power transfer system, wherein at least one of the power transmitting device and the power receiving device is equipped with a coil component described in any one of [1] to

[13] .

[0023]

[17]

[15] A mobile object comprising the power receiving device described in

[15] . Effect of the Invention

[0024] According to the present disclosure, efficient power transmission can be achieved. [Brief description of the drawings]

[0025] [Figure 1] 1 is a diagram illustrating a schematic diagram of a wireless power transmission system to which a coil component according to an embodiment is applied. [Diagram 2]FIG. 1 is a perspective view of a coil component according to an embodiment. [Diagram 3] FIG. 3 is an exploded perspective view of the coil component shown in FIG. 2. [Figure 4] 4 is a cross-sectional view of the coil component taken along line IV-IV in FIG. 2. [Diagram 5] 3A to 3C are cross-sectional views illustrating a method for manufacturing the coil component shown in FIG. 2. [Figure 6] 11 is a table showing the results of a first simulation. [Figure 7] 13 is a table showing the results of a second simulation. [Figure 8] 13 is a table showing the results of a third simulation. [Figure 9] 13 is a graph showing the results of a third simulation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Each embodiment will be described below with reference to the drawings.

[0027] In this specification, the terms "sheet," "film," "plate," and the like are not distinguished from one another solely on the basis of differences in name. Thus, for example, "sheet" is a concept that includes members that may also be called films or plates.

[0028] 1 is a schematic diagram of a wireless power transmission system S to which a coil device 10 according to an embodiment is applied. First, the wireless power transmission system S (hereinafter, abbreviated as power transmission system S) will be described with reference to FIG.

[0029] <Wireless power transmission system> The power transfer system S includes a power transmitting device 1 and a power receiving device 2. The power transmitting device 1 includes a coil component 10 and a high-frequency current supplying unit 1A. The coil component 10 in the power transmitting device 1 functions as a power transmitting coil. The high-frequency current supplying unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil.

[0030] The power receiving device 2 includes a coil component 10 and a conversion unit 2A. The coil component 10 in the power receiving device 2 functions as a power receiving coil. The conversion unit 2A shapes a high-frequency current generated in the coil component 10. The conversion unit 2A includes a rectifier circuit that converts the high-frequency current into a direct current, and the like. The conversion unit 2A may be configured to include, for example, a full-wave rectifier circuit including a plurality of diodes, and a smoothing capacitor.

[0031] In this embodiment, each of the power transmitting device 1 and the power receiving device 2 includes a coil component 10. However, the coil component 10 may be used in only one of the power transmitting device 1 and the power receiving device 2, and a different type of coil component may be used in the other. The coil component 10 may be used in one of the power transmitting device 1 and the power receiving device 2, and a coil component according to another embodiment may be used in the other.

[0032] When transmitting power wirelessly (contactlessly) from the power transmitting device 1 to the power receiving device 2, the power transmitting device 1 supplies a high-frequency current of a predetermined frequency from the high-frequency current supply unit 1A to the coil component 10 serving as a power transmitting coil. At this time, a magnetic field is generated in the coil component 10 by electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil component 10 serving as a power receiving coil in the power receiving device 2. That is, the power receiving device 2 receives the magnetic field or is influenced by the magnetic field, and causes the high-frequency current to flow by electromagnetic induction. The conversion unit 2A converts this high-frequency current into a direct current, and supplies the converted direct current to, for example, a battery not shown.

[0033] The power transmission system S shown in Fig. 1 employs a magnetic resonance method as a power transmission method. However, the coil component 10 according to the present embodiment may be used in a power transmission system that employs an electromagnetic induction method. The power transmission system S is configured as a system that wirelessly transmits power to an electric vehicle. In this case, the power transmitting device 1 is installed on a road, a parking lot, or the like. The power receiving device 2 is installed in the electric vehicle.

[0034] However, the use of the power transmission system S is not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to flying objects such as drones and robots. The power transmission system S may also be used to transmit power to submersibles and exploration robots in the sea. In this way, the power transmission system S can be used to transmit power to various moving objects such as electric vehicles, flying objects, robots, and submersibles. The use of the coil component 5 is not limited to wireless power transmission systems. For example, the coil component 5 may be used in transformers, DC-DC converters, antennas, and the like.

[0035] <Coil parts> The coil device 10 will now be described. Fig. 2 is a perspective view of the coil device 10. Fig. 3 is an exploded perspective view of the coil device 10. Fig. 4 is a cross-sectional view of the coil device 10 taken along line IV-IV in Fig. 2.

[0036] As shown in Fig. 2 to Fig. 4, coil component 10 includes first planar coil 11, second planar coil 12, covering layers 21 to 23, and holding body 30. In the illustrated example, coil component 10 further includes wall portion 35, magnetic shield member 40, first connection terminal 51, and second connection terminal 52. In Fig. 3, holding body 30 is shown divided into a plurality of parts in the thickness direction for convenience of explanation. However, in reality, the plurality of parts 31 to 34 constituting holding body 30 shown divided in Fig. 3 are formed integrally without seams as shown in Fig. 4.

[0037] As shown in FIG. 4, first planar coil 11 and second planar coil 12 overlap with a gap therebetween. In the illustrated example, first planar coil 11 and second planar coil 12 are electrically connected in series, but this is not limited thereto. First planar coil 11 and second planar coil 12 do not have to be electrically and physically connected to each other. At least a portion of holding body 30 is disposed between first planar coil 11 and second planar coil 12, thereby maintaining a state in which first planar coil 11 and second planar coil 12 overlap with a gap therebetween. Holding body 30 also holds first planar coil 11 and second planar coil 12 together.

[0038] Magnetic shield member 40 is disposed facing first planar coil 11. In other words, magnetic shield member 40, first planar coil 11, and second planar coil 12 are disposed in this order.

[0039] First connection terminal 51 is connected to first planar coil 11. Second connection terminal 52 is connected to second planar coil 12.

[0040] (First planar coil and second planar coil) First planar coil 11 has a spiral shape and is made of a conductive material. In the present embodiment, first planar coil 11 includes copper. Specifically, first planar coil 11 is made of copper. However, first planar coil 11 may include a copper alloy, aluminum, an aluminum alloy, or the like.

[0041] 4, the cross-sectional shape of first planar coil 11 in a direction perpendicular to the direction in which first planar coil 11 winds around in a spiral shape is rectangular. First planar coil 11 has first surface 11a facing magnetic shield member 40 and second surface 11b opposite to first surface 11a.

[0042] 2 and 3 indicates a first central axis of first planar coil 11 that passes through the center of the spiral shape of first planar coil 11. Hereinafter, the axial direction of first planar coil 11 refers to a direction extending on first central axis C1 or a direction parallel to first central axis C1. In addition, a direction perpendicular to first central axis C1 is referred to as a radial direction of first planar coil 11.

[0043] The first planar coil 11 has a conductor 11E having a spiral shape formed by a plurality of turn portions 11n. The plurality of turn portions 11n of the first planar coil 11 are arranged in a direction perpendicular to a first central axis C1 of the spiral shape. More specifically, the plurality of turn portions 11n are connected so as to gradually move away from the first central axis C1 of the spiral shape in a radially outward direction. This forms the spiral shape.

[0044] The turn portion 11n is basically a shape in which a linear conductor portion does not form a ring but goes around the first central axis C1 360 degrees. In the case of a so-called planar coil, both ends of the turn portion 11n are shifted in the radial direction. In the case of a plurality of turn portions 11n, a radially outer end of one turn portion 11n is connected to a radially inner end of another turn portion 11n, and the other turn portions 11n extend away from the first central axis C1.

[0045] Hereinafter, the turn portion 11n that is closest to the first central axis C1 may be referred to as the turn portion 111. Also, the turn portion connected to the turn portion 111 may be referred to as the turn portion 112. In this embodiment, the turn portions 11n are made up of seven turn portions 111 to 117. Hereinafter, when describing matters common to each of the turn portions 11n, they will basically be referred to as the turn portion 11n.

[0046] In this embodiment, turn portion 11n winds around to form a rectangular shape. However, turn portion 11n may also have a shape winding around to form a circle. Note that the spiral shape referred to in this specification and disclosure means a planar curved shape wound in a spiral shape. The planar curved shape referred to here also includes a planar pattern that winds around repeatedly while bending like a broken line as shown in the figure. In other words, the spiral shape is a shape that winds around first central axis C1 of first planar coil 11 so as to be gradually positioned outward.

[0047] In the illustrated example, a radially inner end (end close to the first central axis C1) of the turn portion 111 closest to the first central axis C1 is electrically connected to the second planar coil 12. The connection wiring portion 14 illustrated in FIGS. 2 and 3 is a conductor and electrically connects the turn portion 111 and the second planar coil 12 in series. The illustrated connection wiring portion 14 is formed integrally with the second planar coil 12, for example. The connection wiring portion 14 may be connected to the turn portion 111 by ultrasonic connection or the like. On the other hand, a radially outer end (end away from the first central axis C1) of the turn portion 117, which is the farthest from the first central axis C1 among the multiple turn portions 11n, is connected to the first connection terminal 51.

[0048] Here, the radially inward direction of first planar coil 11 (turn portion 11n) means a direction approaching first central axis C1 in the radial direction. Moreover, the radially outward direction of first planar coil 11 (turn portion 11n) means a direction moving away from first central axis C1 in the radial direction. Moreover, in this embodiment, first central axis C1 is determined as follows. First, linear virtual turn portions having a shape similar to that of innermost turn portion 111 are drawn inward in the radial direction in sequence from the radially inner end of innermost turn portion 111 so as to form a spiral shape. Then, drawing is continued until a virtual turn portion that fits within a diameter of 1 cm can be drawn. Then, a line that passes through a radially inner region of the virtual turn portion that fits within a diameter of 1 cm in a direction perpendicular to the circumferential and radial directions of the spiral shape is determined as first central axis C1.

[0049] In the present embodiment, first planar coil 11 is formed by punching a metal plate into a spiral shape, for example, although first planar coil 11 can also be formed by etching a metal foil into a spiral shape.

[0050] The thickness of first planar coil 11 (thickness of conductor 11E) may be, for example, 0.1 mm or more and 1.0 mm or less. The radius of first planar coil 11 (the distance from first central axis C1 to the part farthest in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less. The aspect ratio of first planar coil 11 (conductor 11E) having a rectangular cross-sectional shape is determined by dividing the radial width (width in the radial direction) of first planar coil 11 (conductor 11E) by the thickness of first planar coil 11 (conductor 11E). The aspect ratio of first planar coil 11 (conductor 11E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0051] When transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit power of 1 kW or more, preferably 5 kW or more, in a high-frequency current frequency band of 10 kHz to 200 kHz, particularly 75 kHz to 100 kHz, and further 79 kHz to 90 kHz. In this case, the thickness of first planar coil 11 made of copper is preferably 0.2 mm or more. From this perspective, the lower limit of the thickness of first planar coil 11 may be set to 0.2 mm. Furthermore, when transmitting power to an electric vehicle, an excessively large size is not desirable, and the size may be limited. From this perspective, first planar coil 11 and second planar coil 12 described later, specifically conductor 11E of first planar coil 11 and conductor 12E of second planar coil 12, are preferably formed to a size that fits within a square with one side of 800 mm.

[0052] Moreover, the line width of first planar coil 11 (line width of conductor 11E), i.e., the radial width of each turn portion 11n (width in the radial direction) is not particularly limited. However, considering that it is possible to transmit power of 1 kW or more, preferably 5 kW or more, in a high-frequency current frequency band of, for example, 79 kHz to 90 kHz, the radial width of turn portion 11n may be 2 mm or more and 20 mm or less, 2 mm or more and 16 mm or less, 2 mm or more and 12 mm or less, or 2 mm or more and 8 mm or less. Moreover, the number of turns of first planar coil 11 may be 2 to 12, but is not particularly limited.

[0053] Next, second planar coil 12 also has a spiral shape and contains copper. More specifically, second planar coil 12 is made of copper. The material of second planar coil 12 is not particularly limited, and second planar coil 12 may contain a copper alloy, aluminum, or an aluminum alloy. Second planar coil 12 also has a plate shape, and as shown in FIG. 4, the cross-sectional shape of second planar coil 12 in a direction perpendicular to the direction in which second planar coil 12 winds around in a spiral shape is rectangular. Second planar coil 12 has third surface 12a facing second surface 11b of first planar coil 11 and fourth surface 12b opposite to third surface 12a.

[0054] 2 and 3 indicates a second central axis of second planar coil 12 that passes through the center of the spiral shape of second planar coil 12. Hereinafter, the axial direction of second planar coil 12 refers to a direction extending on second central axis C2 or a direction parallel to second central axis C2. In addition, a direction perpendicular to second central axis C2 is referred to as a radial direction of second planar coil 12.

[0055] In the present embodiment, second planar coil 12 is arranged to be coaxial with first planar coil 11. That is, first central axis C1 of first planar coil 11 and second central axis C2 of second planar coil 12 coincide with each other, in other words, they are located on the same straight line. However, first planar coil 11 and second planar coil 12 may overlap with each other such that first central axis C1 of first planar coil 11 and second central axis C2 of second planar coil 12 are parallel to each other. That is, first planar coil 11 and second planar coil 12 do not have to be coaxial.

[0056] Second planar coil 12 also has conductor 12E having a spiral shape with multiple turn portions 12n. Multiple turn portions 12n of second planar coil 12 are arranged in a direction perpendicular to second central axis C2 of the spiral shape.

[0057] The connection manner of the plurality of turn portions 12n and the names (such as turn portion 121) according to the positions are the same as those of turn portion 11n of first planar coil 11. In the present embodiment, the number of turns of first planar coil 11 and the number of turns of second planar coil 12 are the same, and the plurality of turn portions 12n are configured of seven turn portions 121 to 127. Similarly to turn portion 11n, turn portion 12n winds around to form a rectangular shape. Turn portion 12n may also have a shape winding around to form a circle. The number of turns of first planar coil 11 and the number of turns of second planar coil 12 may differ. For example, turn portion 11n may be rectangular and turn portion 12n may be circular.

[0058] 4, in the present embodiment, any one of a plurality of turn portions 11n of first planar coil 11 and any one of a plurality of turn portions 12n of second planar coil 12 at least partially overlap in the axial direction of first planar coil 11. Turn portions 11n of first planar coil 11 and turn portions 12n of second planar coil 12 that overlap in the axial direction of first planar coil 11 extend at least partially parallel to each other with their respective winding directions aligned. The state in which the winding directions are aligned means that the winding directions of first planar coil 11 and second planar coil 12 do not intersect at a point but overlap a certain distance on the same line.

[0059] As described above, the length of the portions of turn portions 11n of first planar coil 11 and turn portions 12n of second planar coil 12 that overlap and extend parallel to each other may be ½ or more, or ¾ or more, of their respective total lengths. Also, turn portions 11n of first planar coil 11 and turn portions 12n of second planar coil 12 may overlap and extend parallel to each other over their respective total lengths. The present inventors have found that the greater the proportion of overlap between first planar coil 11 and second planar coil 12 that extend parallel to each other, the more eddy current loss can be suppressed.

[0060] As described above, in the illustrated example, the radially inner end of turn portion 111 closest to first central axis C1 is electrically connected to second planar coil 12. More specifically, the radially inner end of turn portion 111 is connected to an inner end of turn portion 121 in second planar coil 12 via connection wiring portion 14. Here, when first planar coil 11 and second planar coil 12 are connected, the direction in which first planar coil 11 winds from an end not connected to second planar coil 12 (a radially outer end of turn portion 117) to an end connected to second planar coil 12 is the same as the direction in which second planar coil 12 winds from an end connected to first planar coil 11 to an end not connected to first planar coil 11 (a radially outer end of turn portion 127).

[0061] The radially outer end of turn portion 127, which is the furthest from second central axis C2, among the plurality of turn portions 12n, is connected to second connection terminal 52. The radially inner and outer directions of second planar coil 12 (turn portions 12n) are defined in the same manner as the radially inner and outer directions of first planar coil 11 described above. The position of second central axis C2 is also determined in the same manner as the first central axis C1. Second planar coil 12 in the present embodiment is also formed, for example, by punching out a metal plate into a spiral shape. However, second planar coil 12 can also be formed by etching a metal foil into a spiral shape.

[0062] The thickness of second planar coil 12 (the thickness of conductor 12E) may be, for example, 0.1 mm or more and 1.0 mm or less. In the illustrated example, in this embodiment, the thickness of first planar coil 11 (the thickness of conductor 11E) is greater than the thickness of second planar coil 12. In other words, the thickness of second planar coil 12 (the thickness of conductor 12E) is smaller than the thickness of first planar coil 11. However, this is not limited to this. The thickness of second planar coil 12 may be the same as the thickness of first planar coil 11, or may be greater than the thickness of first planar coil 11.

[0063] The radius of second planar coil 12 (the distance from second central axis C2 to the part farthest from the center axis C2 in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less, as in the case of first planar coil 11. The aspect ratio of second planar coil 12 (conductor 12E) having a rectangular cross-sectional shape may be 2 to 12 or less, or 3 to 10 or less, as in the case of first planar coil 11. The line width of second planar coil 12 (line width of conductor 12E), i.e., the radial width (width in the radial direction) of each turn portion 12n, may be 2 mm or more and 20 mm or less, 2 mm or more and 16 mm or less, 2 mm or more and 12 mm or less, or 2 mm or more and 8 mm or less. The number of turns of second planar coil 12 may be 2 to 12 or less, but is not particularly limited to this.

[0064] Moreover, first planar coil 11 and second planar coil 12 overlap with a gap therebetween. The dimension of this gap along the axial direction is not particularly limited, but if the gap is too small, eddy current loss occurring in first planar coil 11 and second planar coil 12 when current is supplied thereto tends to be large. Furthermore, if the gap is too large, the thinning of coil component 10 is hindered. Therefore, the dimension of this gap along the axial direction is, for example, 0.5 mm or more and 1.5 mm or less.

[0065] (Holding body and wall) 4, in the present embodiment, a portion of holding body 30 is disposed between first planar coil 11 and second planar coil 12 to fill the gap between first planar coil 11 and second planar coil 12. Holding body 30 integrally holds first planar coil 11 and second planar coil 12. Holding body 30 has fifth surface 30a facing magnetic shield member 40 and sixth surface 30b opposite to fifth surface 30a.

[0066] In the illustrated example, another part of holder 30 covers first surface 11a of first planar coil 11. On the other hand, holder 30 does not cover fourth surface 12b of second planar coil 12. In the illustrated example, sixth surface 30b of holder 30 is flush with fourth surface 12b of second planar coil 12.

[0067] As described above, the holder 30 includes the first layer 31, the second layer 32, the third layer 33, and the fourth layer 34. The first layer 31, the second layer 32, the third layer 33, and the fourth layer 34 are arranged in this order in the direction from the fifth surface 30a to the sixth surface 30b. The first layer 31 forms the fifth surface 30a. The fourth layer 34 forms the sixth surface 30b. In FIG. 3, the first layer 31 and the second layer 32 are shown in an integrated state, and the third layer 33 and the fourth layer 34 are shown in a state separated from the other portions. However, as shown in FIG. 4, the first layer 31, the second layer 32, the third layer 33, and the fourth layer 34 are formed integrally without any seams. Holding body 30 is formed into a shape that encloses first planar coil 11 and second planar coil 12 with parts (31-34) that are integrally formed without seams, and holds first planar coil 11 and second planar coil 12 together.

[0068] First layer 31, second layer 32, third layer 33, and fourth layer 34 are formed to a size that encompasses first planar coil 11 and second planar coil 12 as a whole when viewed in the axial direction of first planar coil 11 and second planar coil 12. First layer 31 is a portion that covers first surface 11a of first planar coil 11 and contacts magnetic shield member 40. Second layer 32 is a portion that overlaps first layer 31 and covers the side surface of first planar coil 11. In other words, second layer 32 is a portion that covers the entire side surface of first planar coil 11 from the inside and outside in the radial direction. Third layer 33 is a portion that is interposed between first planar coil 11 and second planar coil 12. That is, third layer 33 is a portion that fills the gap between first planar coil 11 and second planar coil 12. Fourth layer 34 is a portion that covers the side surfaces of second planar coil 12. In other words, fourth layer 34 is a portion that covers the entire side surfaces of second planar coil 12 from the radial inner and outer sides.

[0069] The first layer 31 has a thickness of, for example, 0.5 mm or more. From the viewpoint of reducing the thickness of the coil component 10 and suppressing an increase in weight, the first layer 31 may have a thickness of, for example, 1.5 mm or less.

[0070] The thickness of third layer 33 is, for example, 0.5 mm or more. However, the thickness of third layer 33 depends on the gap between first planar coil 11 and second planar coil 12. For example, the thickness of third layer 33 is equal to the dimension of the gap between first planar coil 11 and second planar coil 12 in the axial direction minus the thickness of covering layers 22 and 23, which will be described later. For example, when the dimension of the gap between first planar coil 11 and second planar coil 12 in the axial direction is 0.5 mm or more and 1.5 mm or less and each of covering layers 22 and 23 has a thickness of 0.05 mm, the thickness of third layer 33 is 0.4 mm or more and 1.4 mm or less.

[0071] The holder 30 includes a magnetic material. In the illustrated example, each of the first layer 31, the second layer 32, the third layer 33, and the fourth layer 34 includes a magnetic material. Therefore, the holder 30 has magnetism. The holder 30 suppresses eddy current loss and leakage flux by magnetism, and increases the coupling coefficient, thereby improving coil performance. The relative permeability of the holder 30 is preferably 2.0 or more, and may be 2.0 or more and 20.0 or less. The relative permeability of the holder 30 is more preferably 5.0 or more, and may be 5.0 or more and 20.0 or less. The relative permeability of the holder 30 is not particularly limited, but if it is too large, the flexibility and strength of the holder 30 may be undesirably impaired. Therefore, the relative permeability of the holder 30 may be 40 or less.

[0072] Wall portion 35 protrudes in the axial direction from sixth surface 30b of holder 30. Wall portion 35 has a spiral shape when viewed in the axial direction of second planar coil 12, and extends along second planar coil 12 between turn portions 12n of second planar coil 12.

[0073] The wall portion 35 includes a magnetic material. Therefore, the wall portion 35 has magnetism. The wall portion 35 having magnetism can suppress eddy current loss and leakage flux, and increase the coupling coefficient, thereby improving the coil performance. The relative permeability of the wall portion 35 is preferably 2.0 or more, and may be 2.0 or more and 40.0 or less. The relative permeability of the wall portion 35 is more preferably 5.0 or more, and may be 5.0 or more and 40.0 or less. The relative permeability of the wall portion 35 is not particularly limited, but if it is too large, the flexibility and strength of the wall portion 35 may be undesirably impaired. Therefore, the relative permeability of the wall portion 35 may be 40 or less.

[0074] The height of the wall portion 35 is not particularly limited, but may be, for example, 0.5 mm or more, or 1.0 mm or more. The higher the wall portion 35, the greater the effect of suppressing eddy current loss and the higher the coupling coefficient tend to be. On the other hand, the higher the wall portion 35, the more likely it is to be damaged starting from its base. Therefore, the height of the wall portion 35 may be, for example, 10 mm or less. The wall portion 35 does not necessarily have to be provided.

[0075] In the present embodiment, the holder 30 and the wall 35 include, for example, a resin and a plurality or an infinite number of magnetic particles made of a magnetic material. The magnetic particles are held by the resin as a holding material. In this case, the holder 30 is bonded to the first planar coil 11 and the second planar coil 12 with high strength by the resin, so that the holder 30 and the first planar coil 11 and the second planar coil 12 can be stably integrated. In this case, the holder 30 and the wall 35 can be produced, for example, as follows. That is, the magnetic particles are mixed with the softened resin to produce a precursor material for the holder 30. Next, the precursor material is placed in a mold 100 shown in FIG. 5 and hardened. More specifically, the second planar coil 12 is placed in a mold 100 for forming the holder 30 and the wall 35, and then the precursor material is pressed into the mold 100 by a heat press to be molded, and then cooled and solidified. As a result, the wall 35 and the third and fourth layers 33 and 34 covering the second planar coil 12 are integrally produced. A third coating layer 23, which will be described later, may be formed on the third surface 12a of the second planar coil 12. Next, the first planar coil 11 is placed on the precursor material solidified in the mold 100, and the precursor material is pressed into the mold 100 by a hot press to form it, and then cooled and solidified. As a result, the first and second layers 31 and 32 covering the first planar coil 11 are integrally formed with the third and fourth layers 33 and 34. A first and second coating layer 21 and 22, which will be described later, may be formed on the first and second surfaces 11a and 11b of the first planar coil 11.

[0076] The resin contained in the holder 30 has insulating properties. 10 This means that the resistance is Ω·m or more. The resin contained in the wall portion 35 may also have insulating properties.

[0077] The magnetic particles may be made of any one or more of ferrite, particularly ferrite of soft magnetic material, nanocrystalline magnetic material, silicon steel, soft magnetic iron, and amorphous metal. The resin as the holding material may be glass fiber reinforced polyamide. That is, the resin may be made of a material containing polyamide as a thermoplastic resin (thermoplastic material) and glass fiber. However, the material of the holding body 30 and the wall portion 35 is not particularly limited.

[0078] The volume percentage of the magnetic material in the holder 30 depends on the relative dielectric constant of the magnetic material and the magnetic permeability of the holder 30, and may be, for example, 20% or more. If the volume percentage of the magnetic material in the holder 30 is 40% or more, the coil performance can be effectively improved. However, from the viewpoint of suppressing an increase in the weight of the coil component 10, it is preferable that the volume percentage of the magnetic material in the holder 30 is less than 60%. The volume percentage of the magnetic material in the holder 30 can be calculated by measuring the specific gravity of the holder 30.

[0079] (covering layer) As described above, the magnetic holder 30 improves the coil performance of the coil component 10. However, the present inventors performed a simulation on a model of a coil component equipped with a magnetic holder, and measured the Q value of an actual coil component having the same configuration as the model, and found that the Q value of the actual coil component was lower than the Q value of the model obtained by simulation. In other words, even if the magnetic material content of the holder of the actual coil component is the same as that of the model, the Q value of the actual coil component is lower than the Q value of the model. Regarding this point, the present inventors have further obtained the following findings as a result of intensive research. That is, when a simulation is performed on a model of a coil component equipped with a holder having a magnetic material, the simulation is performed under the assumption that the magnetic material is uniformly distributed in the holder. Therefore, when a simulation is performed on a model of a coil component in which the surfaces of the planar coils 11 and 12 are covered with a resin layer that does not contain a magnetic material to obtain a Q value, the Q value is lower than the Q value of a model of a coil component that does not contain such a resin layer (i.e., a model of a coil component in which the magnetic material in the holder is uniformly distributed up to the surfaces of the planar coils 11 and 12) (see the first simulation described later). From the above findings, it is considered that a resin layer that does not contain a magnetic material is formed at the interface of the holder (in other words, the magnetic material in the holder is not in direct contact with the planar coil), which prevents the holder from improving the Q value of the coil component. The reason why the resin layer that does not contain a magnetic material is formed on the holder is considered to be as follows. That is, when the precursor material of the holder hardens, a part of the resin of the precursor material precipitates at the interface, forming a resin layer that does not contain a magnetic material. In particular, when the thickness of the first layer 31 of the holder 30 is 0.5 mm or more, a resin layer that does not contain a magnetic material tends to be formed at the interface of the first layer 31 with the first planar coil 11. Similarly, when the thickness of third layer 33 of holder 30 is 0.5 mm or more, a resin layer not containing magnetic material tends to be formed at the interface between third layer 33 and first planar coil 11 and second planar coil 12.

[0080] Considering these points, the coil component 10 of the present embodiment includes a covering layer 21, 22, and / or 23 that includes a magnetic material and contacts any one of the surfaces 11a, 11b, and 12a of the planar coils 11 and 12. In the illustrated example, the coil component 10 includes a first covering layer 21, a second covering layer 22, and a third covering layer 23. The first covering layer 21 covers the first surface 11a of the first planar coil 11. The first covering layer 21 is located between the first layer 31 of the holder 30 and the first planar coil 11, and directly contacts the first surface 11a of the first planar coil 11. The second covering layer 22 covers the second surface 11b of the first planar coil 11. The second covering layer 22 is located between the third layer 33 of the holder 30 and the first planar coil 11, and directly contacts the second surface 11b of the first planar coil 11. The third covering layer 23 covers the third surface 12a of the second planar coil 12. Third covering layer 23 is located between third layer 33 of holder 30 and second planar coil 12, and is in direct contact with third surface 12a of second planar coil 12. However, coil component 10 does not have to have all of first covering layer 21, second covering layer 22, and third covering layer 23. Coil component 10 only needs to have at least one of first covering layer 21, second covering layer 22, and third covering layer 23.

[0081] The coating layers 21-23 include a magnetic material. In the illustrated example, the thickness of the coating layers 21-23 is 0.1 mm or less. The volume ratio of the magnetic material in the coating layers 21-23 is 60% or more. In such coating layers 21-23, the thickness of the coating layers 21-23 is sufficiently thin and the volume ratio of the magnetic material in the coating layers 21-23 is sufficiently high, so that it is possible to effectively prevent a layer not including a magnetic material from being formed on the surface of the coating layers 21-23 (in other words, the magnetic material in the coating layers 21-23 can be effectively brought into contact with the planar coils 11 and 12). As a result, it is possible to effectively prevent eddy current loss and leakage flux, effectively increase the coupling coefficient, and effectively improve the coil performance. In this case, the thickness of the coating layers 21-23 may be 0.05 mm or less, or may be 0.02 mm or less. In this case, the volume ratio of the magnetic material in the coating layers 21-23 may be 70% or more, 80% or more, or 90% or more.

[0082] In addition, by setting the volume ratio of the magnetic material in the coating layers 21-23 to 75% or more, more preferably 85% or more, it is possible to effectively prevent a layer not containing a magnetic material from being formed on the surface of the coating layers 21-23. For example, when the volume ratio of the magnetic material in the coating layers 21-23 is 100%, it is possible to prevent a layer not containing a magnetic material from being formed on the surface of the coating layers 21-23. In this case, the thickness of the coating layers 21-23 is not particularly limited. However, from the viewpoint of preventing the coil component 10 from becoming large and increasing in weight, it is preferable that the thickness of the coating layers 21-23 is 0.2 mm or less.

[0083] Incidentally, when the volume ratio of the magnetic material in the coating layers 21 to 23 is higher than the volume ratio of the magnetic material in the holder 30, it is believed that the coil performance can also be effectively improved.

[0084] The covering layers 21-23, in which the volume ratio of the magnetic material is less than 100%, may be composed of a resin and a plurality or an infinite number of magnetic particles made of a magnetic material. In this case, the magnetic particles are held by the resin as a holding material. In addition, in this case, the covering layers 21-23 are bonded to the first planar coil 11 or the second planar coil 12 with high strength by the resin, so that the covering layers 21-23 can be stably arranged on the first planar coil 11 or the second planar coil 12. The resin contained in the covering layers 21-23 has insulating properties. The magnetic particles contained in the covering layers 21-23 may be made of any one or more of ferrite, particularly ferrite of a soft magnetic material, nanocrystalline magnetic material, silicon steel, soft electromagnetic iron, and amorphous metal. The resin contained in the covering layers 21-23 may be glass fiber reinforced polyamide. That is, the resin may be made of a material containing polyamide as a thermoplastic resin (thermoplastic material) and glass fiber. However, the materials for forming the coating layers 21 to 23 are not limited to these.

[0085] The planar coils 11 and 12 provided with the resin-containing coating layers 21-23 can be produced, for example, as follows. First, a material obtained by mixing a resin and a magnetic material is formed into a sheet shape to produce a magnetic sheet. Next, the magnetic sheet is attached to a metal plate for producing the planar coils 11 and 12. When producing the first planar coil 11 provided with both coating layers 21 and 22, two magnetic sheets are prepared and attached to both sides of the metal plate. This results in a metal plate covered with the magnetic sheets. Next, this metal plate is punched out together with the magnetic sheets into the shape of the planar coils 11 and 12. This results in the planar coils 11 and 12 provided with the magnetic coating layers 21-23.

[0086] The planar coils 11 and 12 provided with the covering layers 21-23 in which the volume ratio of the magnetic material is 100% can be formed, for example, as follows. First, the magnetic material is placed on a metal plate for producing the planar coils 11 and 12, melted, and then annealed in an atmosphere with an oxygen concentration of 0.1% or less. The temperature of the annealing process may be, for example, 600°C or less. This results in a metal plate on which a covering layer of the magnetic material is formed. Next, this metal plate is punched out together with the covering layer into the shape of the planar coils 11 and 12. This results in the planar coils 11 and 12 provided with the magnetic covering layers 21-23. Even when the volume ratio of the magnetic material is 100%, the above-mentioned magnetic particles may be used as the magnetic material for forming the covering layers 21-23.

[0087] The volume ratio of the magnetic material in the covering layers 21-23 can be calculated by measuring the specific gravity of the covering layers 21-23.

[0088] The relative permeability of the coating layers 21-23 is preferably 10.0 or more, and may be 10.0 or more and 20.0 or less. The relative permeability of the coating layers 21-23 is more preferably 15.0 or more, and may be 15.0 or more and 20.0 or less. The relative permeability of the coating layers 21-23 is not particularly limited, but if it is too large, the flexibility and strength of the coating layers 21-23 may be undesirably impaired. Therefore, the relative permeability of the coating layers 21-23 may be 200 or less.

[0089] In the illustrated example, first coating layer 21 and second coating layer 22 are spiral-shaped when viewed in the axial direction of first planar coil 11 and extend along first planar coil 11. Moreover, third coating layer 23 is spiral-shaped when viewed in the axial direction of second planar coil 12 and extends along second planar coil 12. However, this is not limited thereto. Coating layers 21-22 may have a portion overlapping a gap between adjacent turn portions 11n of first planar coil 11 when viewed in the axial direction of first planar coil 11. In other words, coating layers 21-22 may extend continuously in the radial direction of first planar coil 11 from the innermost portion to the outermost portion of first planar coil 11 when viewed in the axial direction of first planar coil 11. Moreover, coating layer 23 may have a portion overlapping a gap between adjacent turn portions 12n of second planar coil 12 when viewed in the axial direction of second planar coil 12. In other words, coating layer 23 may extend continuously in the radial direction of second planar coil 12 from the innermost portion to the outermost portion of second planar coil 12 when viewed in the axial direction of second planar coil 12.

[0090] (Magnetic shielding material) Magnetic shield member 40 is provided to suppress magnetic transmission and / or leakage magnetic field. Magnetic shield member 40 is disposed to face first surface 11a of first planar coil 11 and fifth surface 30a of holding body 30. Magnetic shield member 40 is a sheet-like member separate from first planar coil 11, second planar coil 12, coating layers 21-23, and holding body 30. Magnetic shield member 40 being separate from first planar coil 11, second planar coil 12, coating layers 21-23, and holding body 30 means that magnetic shield member 40 is not integrated with first planar coil 11, second planar coil 12, coating layers 21-23, and holding body 30. However, magnetic shield member 40 and holding body 30 may be joined via an adhesive layer or the like. Magnetic shield member 40 is formed to have a size that includes first planar coil 11 and second planar coil 12 in a planar view. Magnetic shield member 40 overlaps first planar coil 11, second planar coil 12, coating layers 21-23, and holding body 30, and is in direct contact with holding body 30 among them.

[0091] The magnetic shield member 40 in the present embodiment has magnetism and includes or is made of a magnetic material. In the coil component 10, a magnetic field is generated when a current is supplied to the first planar coil 11 and the second planar coil 12. The magnetic field generated in the coil component 10 spreads in all directions with respect to the central axes C1 and C2 of the first planar coil 11 and the second planar coil 12. At this time, the magnetic shield member 40 has magnetism, so that the spreading magnetic flux lines can be oriented toward the central axes C1 and C2. The coil component 10 may be installed in a vehicle, and in this case, if the magnetic field generated by the coil component 10 flows toward other vehicle components, the vehicle components may be adversely affected. In such a case, the magnetic shield member 40 can suppress the leakage magnetic field that does not contribute to the generation of the current.

[0092] The magnetic shield member 40 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the magnetic shield member 40 includes ferrite, preferably soft ferrite. In the present embodiment, the magnetic shield member 40 includes plate-shaped ferrite. More specifically, the magnetic shield member 40 is configured by arranging a plurality of plate-shaped ferrites in a sheet shape.

[0093] The relative permeability of the magnetic shield member 40 may be equal to or greater than 500, or equal to or greater than 1000. The relative permeability of the magnetic shield member 40 may be equal to or greater than 500 and equal to or less than 3000, or equal to or greater than 1000 and equal to or less than 3000. Note that the relative permeability in this specification is a value measured at a frequency of 85 kHz and an environmental temperature of 23 degrees.

[0094] (Connection terminal) 2 and 3, the first connection terminal 51 is connected to a radially outer end of the turn portion 117 of the first planar coil 11. The second connection terminal 52 is connected to a radially outer end of the turn portion 127 of the second planar coil 12. The first connection terminal 51 and the second connection terminal 52 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A. The connection between the first connection terminal 51 and the turn portion 117 and the connection between the second connection terminal 52 and the turn portion 127 may be performed by ultrasonic bonding. However, the connection method is not limited, and for example, a connection using a conductive adhesive may be adopted.

[0095] <First simulation> Hereinafter, the results of performance evaluation of a model of a coil component in which the surface of the planar coils 11, 12 is covered with a resin layer not containing a magnetic material (hereinafter also referred to as a "non-magnetic resin layer") and a model of a coil component not containing a non-magnetic resin layer will be described. In the performance evaluation described below, the Q value, Z (impedance (Ω)), and L (inductance (μH)) of each model were calculated from the first simulation. The first simulation was performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd. The first simulation was performed under the assumption that the magnetic material of the holder of each model is uniformly distributed in the holder 30. That is, the first simulation was performed under the assumption that a layer not containing a magnetic material is not formed at the interface of the holder 30 with its adjacent layer (for example, the interface with the planar coils 11, 12 when the holder 30 is in direct contact with the planar coils 11, 12).

[0096] The common conditions for each model in the first simulation are as follows: First planar coil 11 is made of copper and has a thickness of 0.5 mm. Second planar coil 12 is made of copper and has a thickness of 0.5 mm. The high-frequency current supplied is 40A and the frequency is 85kHz. The electrical conductivity of the first planar coil 11 made of copper is 3.77×10 7 The electrical conductivity of the second planar coil 12 made of copper is 3.77×10 7 [S / m]. The magnetic shield member 40 has a relative magnetic permeability of 3,000. An aluminum shielding member is further provided to cover magnetic shielding member 40 from the side opposite to the side where first planar coil 11 is located.

[0097] The individual conditions of the first simulation model are as follows: (Model 1-1) The relative magnetic permeability of the holder 30 and the wall portion 35 is 5. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 55%. Surfaces 11a, 11b, and 12a of planar coils 11 and 12 are not covered with a nonmagnetic resin layer. In other words, surfaces 11a, 11b, and 12a of planar coils 11 and 12 are in direct contact with holder 30 on which magnetic material is uniformly distributed. (Model 1-2) The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%. Surfaces 11a, 11b, and 12a of planar coils 11 and 12 are not covered with a nonmagnetic resin layer. In other words, surfaces 11a, 11b, and 12a of planar coils 11 and 12 are in direct contact with holder 30 on which magnetic material is uniformly distributed. (Models 1-3) The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%. First surface 11a of first planar coil 11 is covered with a nonmagnetic resin layer having a thickness of 0.1 mm. Second surface 11b of first planar coil 11 and third surface 12a of second planar coil 12 are not covered with a nonmagnetic resin layer. (Models 1-4) The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%. Second surface 11b of first planar coil 11 is covered with a nonmagnetic resin layer having a thickness of 0.1 mm. First surface 11a of first planar coil 11 and third surface 12a of second planar coil 12 are not covered with a nonmagnetic resin layer. (Models 1-5) The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%. Third surface 12a of second planar coil 12 is covered with a nonmagnetic resin layer having a thickness of 0.1 mm. First surface 11a and second surface 11b of first planar coil 11 are not covered with a nonmagnetic resin layer. (Models 1-6) The relative magnetic permeability of the holder 30 and the wall portion 35 is 5. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 55%. The surfaces 11a, 11b, and 12a of the planar coils 11 and 12 are covered with non-magnetic resin layers, each having a thickness of 0.1 mm. (Models 1-7) The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%. The surfaces 11a, 11b, and 12a of the planar coils 11 and 12 are covered with non-magnetic resin layers, each having a thickness of 0.1 mm.

[0098] FIG. 6 shows the Q value, Z (impedance (Ω)) and L (inductance (μH)) of each model in the first simulation. As can be seen from FIG. 6, when comparing models with the same relative permeability of the holder 30, the Q value of the model in which the surfaces 11a, 11b, and 12a of the planar coils 11 and 12 are not covered with a nonmagnetic resin layer tends to be higher than the Q value of the model in which any of the surfaces 11a, 11b, and 12a of the planar coils 11 and 12 are covered with a nonmagnetic resin layer. That is, the Q value of the model 1-1 is higher than the Q value of the model 1-6, and the Q value of the model 1-2 is higher than the Q values ​​of the models 1-3 to 1-5 and 1-7. In addition, the Q value of the model in which any of the surfaces 11a, 11b, and 12a of the planar coils 11 and 12 are not covered with a nonmagnetic resin layer is lower than the Q value of the model in which all of the surfaces 11a, 11b, and 12a of the planar coils 11 and 12 are covered with a nonmagnetic resin layer. That is, the Q values ​​of models 1-2 to 1-5 are higher than the Q value of model 1-7.

[0099] It can be seen from FIG. 6 that the nonmagnetic resin layers covering the surfaces 11a, 11b, and 12a of the planar coils 11 and 12 prevent the Q value of the coil device 10 from being improved.

[0100] <Second Simulation> Next, the results of performance evaluation of models of coil components including coating layers at different positions are described. In the performance evaluation described below, the Q value, Z (impedance (Ω)), and L (inductance (μH)) of each model were calculated from the second simulation. The second simulation was also performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd.

[0101] The common conditions for each model in the second simulation are as follows: First planar coil 11 is made of copper and has a thickness of 0.5 mm. Second planar coil 12 is made of copper and has a thickness of 0.5 mm. The high-frequency current supplied is 40A and the frequency is 85kHz. The electrical conductivity of the first planar coil 11 made of copper is 3.77×10 7 The electrical conductivity of the second planar coil 12 made of copper is 3.77×10 7 [S / m]. The relative magnetic permeability of the holder 30 and the wall portion 35 is 5. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 55%. The magnetic shield member 40 has a relative magnetic permeability of 3,000. An aluminum shielding member is further provided to cover magnetic shielding member 40 from the side opposite to the side where first planar coil 11 is located.

[0102] The specific conditions of the second simulation model are as follows: (Model 2-1) First surface 11 a of first planar coil 11 is covered with first covering layer 21 . The thickness of the first coating layer 21 is 0.1 mm. The first covering layer 21 has a relative magnetic permeability of 100. The volume ratio of the magnetic material in the first covering layer 21 is 100%. Second surface 11b of first planar coil 11 and third surface 12a of second planar coil 12 are not covered by covering layers 22, . (Model 2-2) Third surface 12a of second planar coil 12 is covered with third covering layer 23. The thickness of the third coating layer 23 is 0.1 mm. The third covering layer 23 has a relative magnetic permeability of 100. The volume ratio of the magnetic material in the third covering layer 23 is 100%. First surface 11a and second surface 11b of first planar coil 11 are not covered by covering layers 21, 22.

[0103] Fig. 7 shows the Q value, Z (impedance (Ω)), and L (inductance (μH)) of each model in the second simulation. As can be seen from Fig. 7, the difference in the position of the coating layer (i.e., which of the surfaces 11a, 11b, and 12a of the planar coils 11 and 12 is covered by the coating layer) does not significantly affect the Q value of the model.

[0104] <Third Simulation> Next, the results of performance evaluation of models of coil components having coating layers 21 to 23 with different volume ratios of magnetic material will be described. In the performance evaluation described below, the Q value of each model was calculated from the third simulation. The third simulation was also performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd.

[0105] The common conditions for each model in the third simulation are as follows: First planar coil 11 is made of copper and has a thickness of 0.5 mm. Second planar coil 12 is made of copper and has a thickness of 0.5 mm. The high-frequency current supplied is 40A and the frequency is 85kHz. The electrical conductivity of the first planar coil 11 made of copper is 3.77×10 7 The electrical conductivity of the second planar coil 12 made of copper is 3.77×10 7[S / m]. The magnetic shield member 40 has a relative magnetic permeability of 3,000. An aluminum shielding member is further provided to cover magnetic shielding member 40 from the side opposite to the side where first planar coil 11 is located.

[0106] The common conditions for the models 3-1 to 3-5 of the third simulation are as follows. First surface 11a of first planar coil 11 is covered with first covering layer 21. First covering layer 21 has a thickness of 0.1 mm. Second surface 11b of first planar coil 11 and third surface 12a of second planar coil 12 are not covered by covering layers 22, . The relative magnetic permeability of the holder 30 and the wall portion 35 is 5. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 55%.

[0107] The individual conditions for models 3-1 to 3-5 are as follows. (Model 3-1) The volume ratio of the magnetic material in the first coating layer 21 is 25%. (Model 3-2) The volume ratio of the magnetic material in the first covering layer 21 is 50%. (Model 3-3) The volume ratio of the magnetic material in the first covering layer 21 is 67%. (Model 3-4) The volume ratio of the magnetic material in the first covering layer 21 is 75%. (Model 3-5) The volume ratio of the magnetic material in the first covering layer 21 is 100%.

[0108] The common conditions for models 3-6 to 3-10 of the third simulation are as follows. First surface 11 a of first planar coil 11 is covered with first covering layer 21 . The thickness of the first coating layer 21 is 0.1 mm. Second surface 11b of first planar coil 11 and third surface 12a of second planar coil 12 are not covered by covering layers 22, . The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%.

[0109] The individual conditions for models 3-6 to 3-10 are as follows. (Models 3-6) The volume ratio of the magnetic material in the first covering layer 21 is 25%. (Models 3-7) The volume ratio of the magnetic material in the first covering layer 21 is 50%. (Model 3-8) The volume ratio of the magnetic material in the first covering layer 21 is 67%. (Model 3-9) The volume ratio of the magnetic material in the first covering layer 21 is 75%. (Model 3-10) The volume ratio of the magnetic material in the first covering layer 21 is 100%.

[0110] The common conditions for models 3-11 to 3-15 of the third simulation are as follows. Third surface 12a of second planar coil 12 is covered with third covering layer 23. The thickness of the third coating layer 23 is 0.1 mm. First surface 11a and second surface 11b of first planar coil 11 are not covered by covering layers 21, 22. The relative permeability of the holder 30 and the wall portion 35 is 10. The volume ratio of the magnetic material in the holder 30 and the wall portion 35 is 58%.

[0111] The individual conditions for models 3-11 to 3-15 are as follows. (Model 3-11) The volume ratio of the magnetic material in the third covering layer 23 is 25%. (Model 3-12) The volume ratio of the magnetic material in the third covering layer 23 is 50%. (Model 3-13) The volume ratio of the magnetic material in the third covering layer 23 is 67%. (Model 3-14) The volume ratio of the magnetic material in the third covering layer 23 is 75%. (Model 3-15) The volume ratio of the magnetic material in the third covering layer 23 is 100%.

[0112] 8 and 9 show the Q values ​​of each model in the third simulation. As can be seen from Figs. 8 and 9, the Q value of the model increases as the volume ratio of the magnetic material in the coating layers 21 and 23 increases. The Q values ​​of models 3-3 and 3-4 are 90% or more of the Q value of model 3-5. The Q values ​​of models 3-8 and 3-9 are 90% or more of the Q value of model 3-10. The Q values ​​of models 3-13 and 3-14 are 90% or more of the Q value of model 3-15.

[0113] Coil component 10 according to the present embodiment described above includes first planar coil 11, second planar coil 12, holding body 30, and at least one covering layer 21-23. First planar coil 11 has first surface 11a and second surface 11b opposite first surface 11a. Second planar coil 12 has third surface 12a facing second surface 11b and fourth surface 12b opposite third surface 12a. Holding body 30 includes a magnetic material. At least a portion of holding body 30 is disposed between first planar coil 11 and second planar coil 12, and holds first planar coil 11 and second planar coil 12. At least one covering layer 21-23 includes a magnetic material. At least one of the coating layers 21-23 is disposed between the first surface 11a, the second surface 11b, and / or the third surface 12a and the holder 30, and is in contact with the first surface 11a, the second surface 11b, and / or the third surface 12a. The volume ratio of the magnetic material in the coating layers 21-23 is 60% or more. The coating layers 21-23 have a thickness of 0.1 mm or less.

[0114] Alternatively, coil device 10 according to the present embodiment includes first planar coil 11, second planar coil 12, holding body 30, and at least one covering layer 21-23. First planar coil 11 has first surface 11a and second surface 11b opposite first surface 11a. Second planar coil 12 has third surface 12a facing second surface 11b and fourth surface 12b opposite third surface 12a. Holding body 30 includes a magnetic material. At least a portion of holding body 30 is disposed between first planar coil 11 and second planar coil 12, and holds first planar coil 11 and second planar coil 12. At least one covering layer 21-23 includes a magnetic material. At least one of the covering layers 21-23 is disposed between the first surface 11a, the second surface 11b, and / or the third surface 12a and the holder 30, and is in contact with the first surface 11a, the second surface 11b, and / or the third surface 12a. The volume ratio of the magnetic material in the covering layers 21-23 is 75% or more.

[0115] According to the coil component 10 of this embodiment, the holding body 30 suppresses the magnetic field leakage and the proximity effect, thereby improving the performance of the coil component 10. Furthermore, the coating layers 21-23 further suppress the magnetic field leakage and the proximity effect, thereby further improving the performance of the coil component 10.

[0116] In the coil component 10 according to the present embodiment, the volume ratio of the magnetic material in the coating layers 21 to 23 is 100%. In this case, the coating layers 21 to 23 effectively suppress magnetic field leakage and the proximity effect, and the performance of the coil component 10 is effectively improved.

[0117] In the coil component 10 according to the present embodiment, the volume ratio of the magnetic material in the coating layers is higher than the volume ratio of the magnetic material in the holder. In this case, the coating layers 21 to 23 effectively suppress magnetic field leakage and the proximity effect, and the performance of the coil component 10 is effectively improved.

[0118] In coil component 10 according to the present embodiment, holder 30 includes third layer 33 disposed between second surface 11b and third surface 12a. Third layer 33 has a thickness of 0.5 mm or more. At least one coating layer 21-23 includes second coating layer 22 disposed between third layer 33 and second surface 11b and in contact with second surface 11b. In this case, a layer not including a magnetic material tends to be formed on the surface of third layer 33 facing first planar coil 11 and second planar coil 12, but second coating layer 22 effectively suppresses leakage of the magnetic field and the proximity effect, thereby effectively improving the performance of coil component 10.

[0119] In coil component 10 according to the present embodiment, holder 30 includes third layer 33 disposed between second surface 11b and third surface 12a. Third layer 33 has a thickness of 0.5 mm or more. At least one coating layer 21-23 includes third coating layer 23 disposed between third layer 33 and third surface 12a and in contact with third surface 12a. In this case, a layer not including a magnetic material tends to be formed on the surface of third layer 33 facing first planar coil 11 and second planar coil 12, but third coating layer 23 effectively suppresses magnetic field leakage and the proximity effect, thereby effectively improving the performance of coil component 10.

[0120] In the coil component 10 according to the present embodiment, the holder 30 includes a first layer 31 facing the first surface 11a. The first layer 31 has a thickness of 0.5 mm or more. At least one of the coating layers 21-23 includes a first coating layer 21 disposed between the first layer 31 and the first surface 11a and in contact with the first surface 11a. In this case, a layer not including a magnetic material tends to be formed on the surface of the first layer 31 facing the first planar coil 11, but the first coating layer 21 effectively suppresses leakage of the magnetic field and the proximity effect, thereby effectively improving the performance of the coil component 10.

[0121] In coil component 10 according to the present embodiment, coating layers 21-23 contain magnetic particles and a resin that holds the magnetic particles. In this case, coating layers 21-23 are bonded to first planar coil 11 or second planar coil 12 with high strength by the resin, and therefore coating layers 21-23 can be stably disposed on first planar coil 11 or second planar coil 12.

[0122] In coil device 10 according to the present embodiment, retainer 30 contains magnetic particles and a resin that retains the magnetic particles. In this case, retainer 30 is bonded to first planar coil 11 and second planar coil 12 with high strength by the resin, and therefore retainer 30 can be integrated with first planar coil 11 and second planar coil 12 in a stable manner.

[0123] Furthermore, in the coil component 10 according to the present embodiment, the holder 30 has a fifth surface 30a facing the same side as the first surface 11a. The coil component 10 further includes a magnetic shield member 40 disposed opposite the first surface 11a and the fifth surface 30a. In this case, the magnetic shield member 40 suppresses magnetic transmission and / or leakage magnetic field, thereby effectively improving the performance of the coil component 10.

[0124] In the coil component 10 according to the present embodiment, the holder 30 has a sixth surface 30b facing the same side as the fourth surface 12b. The coil component 10 further includes a wall portion 35 that is magnetic and protrudes from the sixth surface 30b. In this case, it is possible to effectively improve the transmission efficiency of the magnetic flux sent from the coil component 10 or received from another coil component.

[0125] In coil component 10 according to the present embodiment, first planar coil 11 and second planar coil 12 are plate-shaped. In this case, the dimensions (particularly the thickness) of coil component 10 can be effectively reduced. Also, by bringing coating layers 21-23 into contact with first planar coil 11 and / or second planar coil 12, the performance of coil component 10 can be effectively improved.

[0126] Although the embodiment of the present disclosure has been described above, various modifications may be made to the above-described embodiment, and such modifications are also within the technical scope of the present disclosure. [Explanation of symbols]

[0127] S…Power transmission system 1...Power transmission device 1A…High frequency current supply 2...Power receiving device 2A…Conversion section 10...Coil parts 11…First planar coil 11n…Turn section 11E…Conductor 12…Second planar coil 12E…Conductor 21...First coating layer 22…Second coating layer 23…Third coating layer 30...Holding body 31…First layer 32…Second layer 33…Third layer 34…Fourth layer 35…Wall part 40...Magnetic shielding material 51…First connection terminal 52…Second connection terminal C1…First central axis line C2…Second central axis line

Claims

1. a first planar coil having a first surface and a second surface opposite the first surface; a second planar coil having a third surface facing the second surface and a fourth surface opposite the third surface; a holder including a magnetic material, at least a portion of which is disposed between the first planar coil and the second planar coil, the holder holding the first planar coil and the second planar coil; At least one coating layer including a magnetic material, the at least one coating layer being disposed between the first surface, the second surface, and / or the third surface and the holder and in contact with the first surface, the second surface, and / or the third surface; Equipped with The volume ratio of the magnetic material in the coating layer is 60% or more, A coil component, wherein the coating layer has a thickness of 0.1 mm or less.

2. a first planar coil having a first surface and a second surface opposite the first surface; a second planar coil having a third surface facing the second surface and a fourth surface opposite the third surface; a holder including a magnetic material, at least a portion of which is disposed between the first planar coil and the second planar coil, the holder holding the first planar coil and the second planar coil; At least one coating layer including a magnetic material, the at least one coating layer being disposed between the first surface, the second surface, and / or the third surface and the holder and in contact with the first surface, the second surface, and / or the third surface; Equipped with A coil component, wherein the volume ratio of the magnetic material in the coating layer is 75% or more.

3. The coil component according to claim 1 , wherein a volume ratio of the magnetic material in the covering layer is 100%.

4. The coil component according to claim 1 , wherein a volume ratio of the magnetic material in the covering layer is higher than a volume ratio of the magnetic material in the holding body.

5. the holder includes a third layer portion disposed between the second surface and the third surface, The third layer has a thickness of 0.5 mm or more, The coil component according to claim 1 , wherein the at least one coating layer includes a second coating layer disposed between the third layer portion and the second surface and in contact with the second surface.

6. the holder includes a third layer portion disposed between the second surface and the third surface, The third layer has a thickness of 0.5 mm or more, The coil component according to claim 1 , wherein the at least one coating layer includes a third coating layer disposed between the third layer portion and the third surface and in contact with the third surface.

7. the holder includes a first layer portion facing the first surface, The first layer has a thickness of 0.5 mm or more, The coil component according to claim 1 , wherein the at least one coating layer includes a first coating layer disposed between the first layer portion and the first surface and in contact with the first surface.

8. The coil component according to claim 1 , wherein the coating layer includes magnetic particles and a resin that holds the magnetic particles.

9. The coil component according to claim 1 , wherein the holding body includes magnetic particles and a resin that holds the magnetic particles.

10. The holder has a fifth surface facing the same side as the first surface, The coil component according to claim 1 , further comprising a magnetic shield member disposed opposite the first surface and the fifth surface.

11. The coil component according to claim 10 , wherein the magnetic shielding member includes ferrite.

12. the holder has a sixth surface facing the same side as the fourth surface, The coil component according to claim 1 , further comprising a wall portion having magnetism and protruding from the sixth surface.

13. The coil component according to claim 1 , wherein the first planar coil and the second planar coil are plate-shaped.

14. A power transmitting device comprising the coil component according to claim 1 or 2.

15. A power receiving device comprising the coil component according to claim 1 or 2.

16. The power transmission device and the power receiving device are provided. A power transfer system, wherein at least one of the power transmitting device and the power receiving device comprises the coil component according to claim 1 or 2.

17. A mobile object comprising the power receiving device according to claim 15.

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