Coil component, coil intermediate material, power transmission device, power reception device, and power transfer system

Abstract

To provide a coil component, a coil intermediate material, a power transmission device, a power reception device, and a power transfer system for improving radiation performance.SOLUTION: A coil component 10 comprises a planar coil 11 having a spiral shape, a first holding member 20 for holding the planar coil 11, and a second holding member 30 for sandwiching the planar coil 11 together with the first holding member 20. The planar coil 11 includes a plurality of turn parts arranged in a radial direction of the planar coil 11. The first holding member 20 has a contact surface 20S1 in contact with the planar coil 11 and an external surface 20S2 on the opposite side of the contact surface 20S1. First grooves 25 are formed on the external surface 20S2. The first grooves 25 extend in a stripe shape along a direction orthogonal to an axial direction. When viewed from the axial direction, at least some of the first grooves 25 extend in a direction in non-parallel with a direction in which turn parts with which the at least some of the first grooves 25 overlap extend.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Wireless power transmission systems that transmit power in a contactless manner are becoming increasingly popular.

[0003] When transmitting power contactlessly, a high-frequency current is passed through a resonant circuit including a coil. The coil may be formed in a spiral shape, as disclosed in Patent Document 1, for example. Generally, the coil is used while being housed in a hollow case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-27112 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, it has been considered to form a case integrally with a coil and to have the case hold the coil. In other words, it has been considered to form the case as a holding member that holds the coil. In this case, the inner surface of the holding member has a shape corresponding to the shape of the coil and other components associated with the coil. For example, when the coil is formed into a spiral shape, as shown in Patent Document 1, a magnetic body is disposed between adjacent portions of the coil. For this reason, a groove is formed on the inner surface of the holding member to accommodate the tip of the magnetic body.

[0006] Such a holding member can be made using a thermoplastic material or a thermosetting material. Specifically, the holding member can be produced by heating and melting the material, fitting it into a mold having concaves and convexes corresponding to the concaves and convexes on the inner surface of the holding member, and then cooling it. A coil component having a case and a coil integrally formed in this way may be required to have improved heat dissipation performance.

[0007] An object of the present embodiment is to provide a coil component, a coil intermediate material, a power transmitting device, a power receiving device, and a power transfer system that are capable of improving heat dissipation performance. [Means for solving the problem]

[0008] An embodiment of the present disclosure relates to the following [1] to

[20] .

[0009] [1] a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the second surface and holds the planar coil; a second holding member that sandwiches the planar coil between the first holding member and the second holding member, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, the first holding member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, a first groove formed in the outer surface; the first grooves extend in a stripe shape along a direction perpendicular to the axial direction, a coil component in which at least some of the first grooves extend in a direction non-parallel to a direction in which the turn portions with which the at least some of the first grooves overlap extend, as viewed in the axial direction.

[0010] [2] the second holding member has a protrusion extending along the axial direction between adjacent turn portions of the planar coil, a second groove is formed in the contact surface to receive the protrusion; The coil component according to [1], wherein the first groove does not overlap with the second groove when viewed in the axial direction.

[0011] [3] The coil component according to [1] or [2], wherein the width of the first groove is 0.8 mm or more and 1.2 mm or less.

[0012] [4] The coil component according to any one of [1] to [3], wherein the depth of the first groove is 0.8 mm or more and 1.2 mm or less.

[0013] [5] The coil component according to any one of [1] to [4], wherein the width of the first groove is 0.9 to 1.1 times the depth of the first groove.

[0014] [6] The coil component according to any one of [1] to [5], wherein the first holding member is non-magnetic and insulating.

[0015] [7] The coil component according to any one of [1] to [6], wherein the second holding member is magnetic.

[0016] [8] The coil component according to any one of [1] to [7], wherein the planar coil is formed in a plate shape.

[0017] [9] The coil component according to any one of [1] to [8], wherein the planar coil is formed using a Litz wire.

[0018]

[10] a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the second surface and holds the planar coil; the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, the first holding member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, a first groove formed in the outer surface; the first grooves extend in a stripe shape along a direction perpendicular to the axial direction, A coil intermediate material, wherein at least some of the first grooves extend in a direction non-parallel to the direction in which the turn portions with which the at least some of the first grooves overlap extend, as viewed in the axial direction.

[0019]

[11] A power transmission device comprising the coil component according to any one of [1] to [9].

[0020]

[12] A power receiving device comprising the coil component according to any one of [1] to [9].

[0021]

[13] The power transmission device includes a power receiving device. A power transmission system, wherein at least one of the power transmitting device and the power receiving device includes the coil component according to any one of [1] to [9]. [Effects of the Invention]

[0022] According to the present disclosure, the heat dissipation performance of the coil component can be improved. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram schematically illustrating a wireless power transmission system to which a coil component according to an embodiment can be applied. [Figure 2] FIG. 2 is a plan view showing the coil component according to the embodiment. [Figure 3]FIG. 3 is an exploded perspective view showing the coil component according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view (a cross-sectional view taken along line IV-IV in FIG. 2) showing the coil device according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view (cross-sectional view taken along line VV in FIG. 2) showing the coil device according to the embodiment. [Figure 6] FIG. 6 is a perspective view showing a coil intermediate material according to one embodiment, as viewed from the outer surface side of the first holding member. [Figure 7] FIG. 7 is a bottom view showing a coil intermediate material according to one embodiment. [Figure 8] FIG. 8 is a perspective view showing a coil intermediate material according to one embodiment, as viewed from the side of the planar coil. [Figure 9] FIG. 9 is a cross-sectional view illustrating an example of a method for manufacturing a coil component according to an embodiment. [Figure 10] FIG. 10 is a plan view showing a modified example of the coil intermediate material according to the embodiment. [Figure 11] FIG. 11 is a bottom view showing a modified example of the coil intermediate material according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Each embodiment will be described below with reference to the drawings. Note that in the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding.

[0025] Furthermore, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely based on the difference in name. Therefore, for example, "sheet" is a concept that also includes members that can be called films or plates.

[0026] Fig. 1 schematically shows a wireless power transmission system S to which a coil device 10 according to one embodiment is applied. First, the wireless power transmission system S (hereinafter abbreviated as power transmission system S) will be described with reference to Fig. 1. It goes without saying that a coil device different from the coil device 10 according to this embodiment can be applied to the power transmission system S.

[0027] <Wireless power transmission system> The power transmission 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 supply unit 1A. The coil component 10 in the power transmitting device 1 functions as a power transmitting coil component. The high-frequency current supply unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil component.

[0028] 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 component. The conversion unit 2A shapes the 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. The conversion unit 2A may include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0029] 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.

[0030] 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 component. 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 component in the power receiving device 2. That is, the power receiving device 2 receives the magnetic field from the power transmitting device 1 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).

[0031] The power transmission system S shown in FIG. 1 employs a magnetic resonance method as a power transmission method. However, the coil device 10 according to this embodiment may also 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, in a parking lot, or the like. The power receiving device 2 is installed in the electric vehicle.

[0032] 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 drones and other flying objects and robots. The power transmission system S may also be used to transmit power to underwater submersibles and exploration robots. 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 10 is also not limited to wireless power transmission systems. For example, the coil component 10 may be used in transformers, DC-DC converters, antennas, etc.

[0033] <Coil parts> The coil device 10 will now be described. Fig. 2 is a plan view of the coil device 10. Fig. 3 is an exploded perspective view of the coil device 10. Figs. 4 and 5 are cross-sectional views of the coil device 10 taken along central axes C1 and C2 of planar coils 11 and 12, which will be described later.

[0034] As shown in Figures 2 to 5, coil device 10 includes first planar coil 11, second planar coil 12, first holding member 20, second holding member 30, first magnetic shield member 40, second magnetic shield member 50, first connection terminal 61, and second connection terminal 62.

[0035] As shown in FIG. 3 , in coil device 10, first planar coil 11, second planar coil 12, second holding member 30, first magnetic shield member 40, and second magnetic shield member 50 are stacked on first holding member 20 in this order. For ease of explanation, second holding member 30, first magnetic shield member 40, and second magnetic shield member 50 are not shown in FIG. 2 . However, in reality, second holding member 30, first magnetic shield member 40, and second magnetic shield member 50 stack on second planar coil 12, which is shown by a solid line. For ease of explanation, first planar coil 11 is shown by a dashed line in FIG. 2 . Furthermore, in FIGS. 2 and 3 , first connection terminal 61 and second connection terminal 62 are simply shown by a two-dot chain line. Each part of coil device 10 will be described in detail below.

[0036] (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 contains copper. Specifically, first planar coil 11 is made of copper. However, first planar coil 11 may also be made of a copper alloy, aluminum, an aluminum alloy, or the like.

[0037] As shown in FIG. 3, first planar coil 11 is plate-shaped, and as shown in FIGS. 4 and 5, the cross-sectional shape of first planar coil 11 in the direction in which first planar coil 11 winds in a spiral shape, in other words, in a direction perpendicular to the direction in which first planar coil 11 extends in a spiral shape, is rectangular.

[0038] 2 to 5 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. The radial direction of a circle drawn on a plane centered at an arbitrary point on first central axis C1 and perpendicular to first central axis C1 is referred to as the radial direction of first planar coil 11. First planar coil 11 includes first surface 11A and second surface 11B that are opposite each other in the axial direction. First planar coil 11 has second planar coil 12 and the like superimposed on first surface 11A, and second surface 11B faces first holding member 20.

[0039] As shown in Fig. 3, first planar coil 11 has conductor 11E having a spiral shape formed by a plurality of turn portions 11n. The plurality of turn portions 11n of first planar coil 11 are arranged in a direction perpendicular to a first central axis C1 of the spiral shape. Specifically, the plurality of turn portions 11n are connected so as to gradually move away from first central axis C1 of the spiral shape toward the radially outward direction of first planar coil 11. This forms the spiral shape.

[0040] Turn portion 11n is basically a linear conductor portion that does not form a loop but wraps around first central axis C1 360 degrees. In the case of a so-called planar coil, both ends of turn portion 11n are offset in the radial direction of first planar coil 11. In the case of multiple 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 first central axis C1.

[0041] Hereinafter, the turn portion 11n that is closest to the first central axis C1 may be referred to as the turn portion 111. Furthermore, 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 include five turn portions 111 to 115. Hereinafter, when describing matters common to each of the turn portions 11n, they will basically be referred to as the turn portion 11n.

[0042] In this embodiment, the turn portion 11n goes around to form a rectangular shape. However, the turn portion 11n may also have a shape that goes around to form a circle. Note that the "spiral shape" referred to in this specification and this disclosure means a planar curved shape that is wound in a spiral shape. The planar curve referred to here also includes a planar pattern that goes around repeatedly while bending like a broken line, as shown in the figure. In other words, the "spiral shape" refers to a planar curved shape that moves away from the center as it goes around (or moves closer to the center as it goes around).

[0043] The radially inner end (the end closest 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. On the other hand, the radially outer end (the end farthest from the first central axis C1) of the turn portion 115 of the multiple turn portions 11n that is farthest from the first central axis C1 is connected to the first connection terminal 61.

[0044] Here, the radial inward direction of first planar coil 11 (turn portions 11n) refers to a direction approaching first central axis C1 in the radial direction. The radial outward direction of first planar coil 11 (turn portions 11n) refers to a direction moving away from first central axis C1 in the radial direction. In this embodiment, first central axis C1 is determined as follows: First, linear virtual turn portions similar in shape to turn portions 112 are drawn sequentially from the radially inner end of turn portion 112 adjacent to innermost turn portion 111 in a spiral shape extending radially inward. The drawing is continued until a virtual turn portion that fits within a diameter of 1 cm is drawn. 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.

[0045] In the present embodiment, first planar coil 11 is formed by punching a metal plate such as a copper plate or an aluminum plate into a spiral shape, for example. However, first planar coil 11 can also be formed by etching a metal foil such as a copper foil or an aluminum foil into a spiral shape.

[0046] 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 farthest point 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.

[0047] When transmitting power to an electric vehicle using magnetic resonance, it is desirable to be able to transmit 1 kW or more, preferably 5 kW or more, of power in a high-frequency current frequency band of 10 kHz to 200 kHz, particularly 75 kHz to 100 kHz, and even more preferably 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, excessively large size is not desirable, and 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 sides of 800 mm.

[0048] Furthermore, the line width of first planar coil 11 (line width of conductor 11E), i.e., the radial width of each turn portion 11n, is not particularly limited. However, considering that a power of 1 kW or more, preferably 5 kW or more, can be transmitted 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 to 20 mm, 2 mm to 16 mm, 2 mm to 12 mm, or 2 mm to 8 mm. The number of turns in first planar coil 11 may be 4 to 12, but is not particularly limited.

[0049] Next, second planar coil 12 also has a spiral shape, and in this embodiment, second planar coil 12 also contains copper. Specifically, second planar coil 12 is made of copper. The material of second planar coil 12 is not particularly limited, and may be a copper alloy, aluminum, an aluminum alloy, or the like. Second planar coil 12 also has a plate shape, and as shown in FIGS. 4 and 5 , the cross section 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.

[0050] 2 to 5 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. The radial direction of a circle drawn on a plane perpendicular to second central axis C2 and centered at an arbitrary point on second central axis C2 is referred to as the radial direction of second planar coil 12. Second planar coil 12 includes first surface 12A and second surface 12B that are opposite each other in the axial direction. Second planar coil 12 has second holding member 30, first magnetic shield member 40, and second magnetic shield member 50 stacked on first surface 12A, and second surface 12B faces first planar coil 11 (first surface 11A).

[0051] In the present embodiment, second planar coil 12 is arranged coaxially 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.

[0052] 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.

[0053] The connection manner of multiple turn portions 12n and the names (such as turn portion 121) according to their 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 second planar coil 12 are the same, and multiple turn portions 12n include five turn portions 121 to 125. Also, turn portion 12n winds around to form a rectangular shape, similar to turn portion 11n. Note that turn portion 12n may also have a circular shape. Also, the number of turns of first planar coil 11 and second planar coil 12 may differ. Also, for example, turn portion 12n may be rectangular and turn portion 11n may be circular.

[0054] As described above, the radially inner end of turn portion 111 closest to first central axis C1 is electrically connected to second planar coil 12. Specifically, the radially inner end of turn portion 111 is connected to the radially inner end of turn portion 121 of second planar coil 12. Here, when first planar coil 11 and second planar coil 12 are connected, the direction in which first planar coil 11 winds from the end not connected to second planar coil 12 (the radially outer end of turn portion 115) to the end connected to second planar coil 12 is the same as the direction in which second planar coil 12 winds from the end connected to first planar coil 11 to the end not connected to first planar coil 11 (the radially outer end of turn portion 125).

[0055] The radially outer end of turn portion 125, among multiple turn portions 12n, that is farthest from second central axis C2 is connected to second connection terminal 62. 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 this embodiment is also formed by punching out a metal plate, such as a copper plate or an aluminum plate, into a spiral shape, for example. However, second planar coil 12 can also be formed by etching a metal foil, such as a copper foil or an aluminum foil, into a spiral shape.

[0056] In the present embodiment, the thickness of second planar coil 12 (thickness of conductor 12E) may be, for example, 0.1 mm to 1.0 mm. Similarly to first planar coil 11, the radius of second planar coil 12 (the distance from second center axis C2 to the farthest point in the radial direction) may be 80 mm or more, or 80 mm to 450 mm. Similarly to first planar coil 11, the aspect ratio of second planar coil 12 (conductor 12E) having a rectangular cross section may be 2 to 12, or 3 to 10. Similarly to first planar coil 11, the line width of second planar coil 12 (line width of conductor 12E), i.e., the radial width of each turn portion 12n (width in the radial direction), may be 2 mm to 20 mm, 2 mm to 16 mm, 2 mm to 12 mm, or 2 mm to 8 mm. The number of turns of second planar coil 12 may be between 4 and 12, but is not particularly limited to this.

[0057] 4 and 5, first planar coil 11 and second planar coil 12 overlap with a gap in the axial direction. This gap may be 0.5 mm or more and 1.5 mm or less. While the size of the gap is not particularly limited, if the gap is too small, eddy current loss generated in first planar coil 11 and second planar coil 12 when current is supplied tends to be large. Furthermore, if the gap is too large, the thinning of coil device 10 is impaired. The gap between first planar coil 11 and second planar coil 12 is maintained by the presence of second holding member 30 between planar coils 11 and 12, as described below.

[0058] (First holding member) First holding member 20 overlaps first planar coil 11 so as to face second surface 11B of first planar coil 11, and holds first planar coil 11. In the present embodiment, first holding member 20 has a rectangular shape corresponding to the shape of turn portion 11n in a planar view. In coil device 10, for example, when transmitting power, the magnetic fields generated in first planar coil 11 and second planar coil 12 pass through first holding member 20. Therefore, first holding member 20 is preferably non-conductive (insulating) and non-magnetic so as not to interfere with the magnetic field and to prevent eddy currents from being generated.

[0059] Considering that non-conductive (insulating) and non-magnetic properties are preferable, the material of the first holding member 20 is, for example, resin, and may also be fiber reinforced plastic. More specifically, the material of the first holding member 20 may be glass fiber reinforced polyamide. However, the material of the first holding member 20 is not particularly limited. For example, it may not contain glass fiber. Also, thermoplastic resins or thermosetting resins other than polyamide may be used. Note that insulating properties are defined as those having a volume resistivity of 10 10 This means that the resistance is Ω·m or more. Non-magnetic means that it does not exhibit magnetism.

[0060] First holding member 20 is integrated with first planar coil 11 to hold first planar coil 11. In the present embodiment, first planar coil 11 is placed in first holding member forming die 200 (see FIG. 9 ), and then a material for forming first holding member is pressed into die 200 by hot pressing to form the material, which is then cooled and solidified, thereby integrating first planar coil 11 and first holding member 20. In this specification, first holding member 20 integrated with first planar coil 11 is also referred to as coil intermediate material 10M.

[0061] In the present embodiment, first holding member 20 sandwiches first planar coil 11 and second planar coil 12 with second holding member 30. First holding member 20 has contact surface 20S1 that contacts second surface 11B of first planar coil 11. Contact surface 20S1 forms the inner surface of first holding member 20. First holding member 20 also has outer surface 20S2, which is the surface opposite contact surface 20S1.

[0062] 4 and 5, a first groove 25 is formed in the outer surface 20S2. Also, as shown in Figures 4 and 5, a second groove 24 is formed in the contact surface 20S1 to receive a protrusion 32 of a second holding member 30, which will be described later. The first groove 25 and the second groove 24 will be described in detail later.

[0063] (Second holding member) 4 and 5 , second holding member 30 in the present embodiment is integrated with first planar coil 11, second planar coil 12, and first holding member 20 so as to sandwich first planar coil 11 and second planar coil 12 between first holding member 20. In the present embodiment, second holding member 30 has a rectangular shape corresponding to the shape of turn portion 11n in a planar view. As described above, a portion of second holding member 30 is interposed between second planar coil 12 and first magnetic shield member 40, and another portion is interposed between first planar coil 11 and second planar coil 12.

[0064] Specifically, second holding member 30 has base 31 interposed between second planar coil 12 and first magnetic shield member 40, and protrusion 32 protruding from base 31 toward first holding member 20. Base 31 entirely covers first surface 12A of second planar coil 12. When viewed in the axial direction of first planar coil 11 and second planar coil 12, base 31 is formed to a size sufficient to encompass first planar coil 11 and second planar coil 12 entirely. Base 31 and first holding member 20 sandwich first planar coil 11 and second planar coil 12 therebetween.

[0065] Protrusion 32 extends between adjacent turn portions of first planar coil 11 along the axial direction of first planar coil 11. Therefore, protrusion 32 is formed along first planar coil 11, which has a spiral shape. In the illustrated example, protrusion 32 is formed in a spiral shape corresponding to the spiral shape of first planar coil 11. As described above, protrusion 32 is received in second groove 24 of first holding member 20. In other words, protrusion 32 fills second groove 24 of first holding member 20.

[0066] In the illustrated example, second holding member 30 further includes spacer portion 33 disposed between first planar coil 11 and second planar coil 12. Spacer portion 33 maintains a gap between first planar coil 11 and second planar coil 12. In other words, second planar coil 12 is embedded in second holding member 30. A portion of second holding member 30 that covers second surface 12B of second planar coil 12 is spacer portion 33. Spacer portion 33 contacts first surface 11A of first planar coil 11.

[0067] The second holding member 30 is magnetic as a whole; that is, the base 31, the protruding portion 32, and the spacer portion 33 are all magnetic. The second holding member 30 uses its magnetism to suppress eddy current loss and leakage flux, and to increase the coupling coefficient, thereby improving coil performance. The relative permeability of the second holding member 30 is preferably 2.0 or more, and may be 2.0 to 10.0. The relative permeability of the second holding member 30 is more preferably 5.0 or more, and may be 5.0 to 10.0. The relative permeability of the second holding member 30 is not particularly limited, but if it is too high, the flexibility and strength of the second holding member 30 may be undesirably impaired. Therefore, the relative permeability of the second holding member 30 may be 200 or less.

[0068] Furthermore, by providing second holding member 30 with protrusion 32, coil performance can be effectively improved. The height of protrusion 32 (the distance between the top of protrusion 32 and second surface 11B of first planar coil 11 along the axial direction of first planar coil 11) is not particularly limited, but may be, for example, 0.5 mm or more, or 1.0 mm or more. The higher the height of protrusion 32, the more effective it is in suppressing eddy current loss and the higher the coupling coefficient tends to be. On the other hand, the higher the protrusion 32, the more susceptible it is to breakage, starting from its base. Therefore, the height of protrusion 32 may be, for example, 10 mm or less.

[0069] The second holding member 30 in this embodiment includes, 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.

[0070] The magnetic particles may be made of one or more of ferrite, particularly soft magnetic ferrite, nanocrystalline magnetic material, silicon steel, soft electromagnetic iron, and amorphous metal. The resin used 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 molding material of the second holding member 30 is not particularly limited.

[0071] (First groove) The first grooves 25 are formed for the purpose of improving the heat dissipation performance of the coil device 10. As shown in FIGS. 5 to 7 , the first grooves 25 extend in a stripe pattern along a first direction (direction) d1 that is perpendicular to the axial direction. In this case, for example, when the coil device 10 is installed in a vehicle, the coil device 10 is installed in the vehicle so that the first direction d1 is parallel to the direction of travel of the vehicle, so that wind flows along the first grooves 25. This allows the wind to effectively remove heat generated in the coil device 10. The first direction d1 that is perpendicular to the axial direction may be a direction parallel to one side of the rectangle formed by the first holding member 20.

[0072] Here, at least some of the first grooves 25 extend in a direction non-parallel to the extension direction of the turn portion 11n with which at least some of the first grooves 25 overlap, as viewed in the axial direction. That is, as shown in Fig. 7, the first grooves 25 of the turn portion 11n that overlap the portion 11n2 extending in the second direction d2 extend in a direction (first direction d1) non-parallel to the extension direction of the portion 11n2 (second direction d2). Specifically, the first grooves 25 of the turn portion 11n that overlap the portion 11n2 extending in the second direction d2 extend in the width direction (first direction d1) of the turn portion 11n (portion 11n2). On the other hand, the first groove 25 of the turn portion 11n that overlaps the portion 11n1 extending in the first direction d1 extends in a direction (first direction d1) parallel to the direction in which the portion 11n1 extends (first direction d1). The second direction d2 is a direction non-parallel to the first direction d1. The second direction may be a direction perpendicular to the first direction d1.

[0073] The width of the first groove 25 is not particularly limited, and may be, for example, 0.1 to 0.8 times the width of the turn portion 11n. The width (length along the second direction) of the first groove 25 may be 0.8 to 1.2 mm, for example, 1 mm. When the width of the first groove 25 is 0.8 mm or more, the first groove 25 can be easily formed. When the width of the first groove 25 is 1.2 mm or more, the number of first grooves 25 formed on the outer surface 20S2 of the first holding member 20 can be increased. This increases the overall surface area of ​​the first grooves 25 formed on the outer surface 20S2. This further improves the heat dissipation effect of the first grooves 25.

[0074] Furthermore, the depth (length along the axial direction) of the first grooves 25 may be 0.8 mm or more and 1.2 mm or less, and may be 1 mm, for example. When the width of the first grooves 25 is 0.8 mm or more, the surface area of ​​each first groove 25 can be increased. This further improves the heat dissipation effect of the first grooves 25. When the depth of the first grooves 25 is 1.2 mm or less, a decrease in the strength of the first holding member 20 can be suppressed. Furthermore, when the depth of the first grooves 25 is 1.2 mm or less, the first grooves 25 can be easily formed.

[0075] Furthermore, the width of the first grooves 25 may be 0.9 to 1.1 times the depth of the first groove. This increases the surface area of ​​each first groove 25. This further improves the heat dissipation effect of the first grooves 25. Furthermore, by having the width of the first grooves 25 be 0.9 to 1.1 times the depth of the first groove, the first grooves 25 can be easily formed.

[0076] The first groove 25 may also be formed for the purpose of suppressing warpage of the first holding member 20. According to the knowledge of the present inventors, warpage of the first holding member 20 occurs when the first holding member 20, which has been heated and molded in the mold 200, cools and solidifies. This is thought to be because the degree of contraction of the first holding member 20 differs between the contact surface 20S1 side and the outer surface 20S2 side when the first holding member 20 cools. The reason for the difference in the degree of contraction of the first holding member 20 between the contact surface 20S1 side and the outer surface 20S2 side is thought to be because the amount of material forming the first holding member 20 differs between the contact surface 20S1 side and the outer surface 20S2 side of the first holding member 20. That is, the second groove 24 is formed in the contact surface 20S1 of the first holding member 20. For this reason, if no grooves are formed on outer surface 20S2 of first holding member 20, the amount of the material on contact surface 20S1 side of first holding member 20 is less than the amount of the material on outer surface 20S2 side by at least the volume of second groove 24. Therefore, in this embodiment, by forming first groove 25 on outer surface 20S2, it is thought that the difference between the amount of material on contact surface 20S1 side and the amount of material on outer surface 20S2 side can be reduced, and warping of first holding member 20 can be suppressed.

[0077] First groove 25 is preferably formed in region 20R2 on outer surface 20S2, corresponding to region 20R1 on contact surface 20S1 where second groove 24 is formed. This reduces the difference between the degree of contraction of first holding member 20 in each region on contact surface 20S1 and the corresponding region on outer surface 20S2, thereby effectively suppressing warpage of first holding member 20. In the illustrated example, region 20R1 on contact surface 20S1 and region 20R2 on outer surface 20S2 overlap when viewed in the axial direction of first planar coil 11 (see FIGS. 4 and 5). That is, first groove 25 is formed in region 20R2 on outer surface 20S2, which overlaps region 20R1 on contact surface 20S1, which includes central axis C1 and second groove 24, when viewed in the axial direction of first planar coil 11 (see FIGS. 4 and 6).

[0078] In the illustrated example, first groove 25 is formed only in the region overlapping turn portion 11n as viewed in the axial direction. That is, first groove 25 does not overlap second groove 24 as viewed in the axial direction of first planar coil 11. This facilitates achieving the desired depths of second groove 24 and first groove 25. In other words, it is possible to prevent second groove 24 and first groove 25 from communicating with each other to form a through hole in first holding member 20. Alternatively, it is possible to prevent the distance between the bottom surface of second groove 24 and outer surface 20S2 and / or the distance between the bottom surface of first groove 25 and contact surface 20S1 from being too small, thereby reducing the strength of first holding member 20 below the desired strength.

[0079] (Second groove) As described above, second groove 24 of first holding member 20 receives protrusion 32 of second holding member 30. As shown in FIGS. 4 and 5 , protrusion 32 is formed in a region on second holding member 30 that overlaps with region 10MR on coil intermediate material 10M, which includes first planar coil 11 and its central axis C1, as viewed in the axial direction of first planar coil 11. Therefore, second groove 24 is also formed in region 20R1 on contact surface 20S1, which corresponds to region 10MR. In the illustrated example, region 10MR on coil intermediate material 10M and region 20R1 on contact surface 20S1 overlap as viewed in the axial direction of first planar coil 11.

[0080] In the illustrated example, protrusion 32 is formed along the spiral shape of first planar coil 11. Therefore, second groove 24 is also formed along the spiral shape of first planar coil 11 (see FIG. 8 ). In the illustrated example, protrusion 32 is formed in a spiral shape corresponding to the spiral shape of first planar coil 11. Therefore, second groove 24 is also formed in a spiral shape corresponding to the spiral shape of first planar coil 11.

[0081] (First magnetic shield member) First magnetic shield member 40 is provided to suppress magnetic transmission and / or leakage magnetic field. First magnetic shield member 40 is a sheet-like member separate from first planar coil 11, second planar coil 12, first holding member 20, and second holding member 30. Being separate from first planar coil 11, second planar coil 12, first holding member 20, and second holding member 30 means that first magnetic shield member 40 is not integrated with first planar coil 11, second planar coil 12, first holding member 20, and second holding member 30. However, first magnetic shield member 40 and second holding member 30 may be joined via an adhesive layer or the like. First magnetic shield member 40 is formed to a size that encompasses first planar coil 11, second planar coil 12, and second holding member 30 in a planar view. First magnetic shield member 40 overlaps first planar coil 11, second planar coil 12, and second holding member 30, and is in direct contact with second holding member 30 among these.

[0082] In this embodiment, first magnetic shield member 40 is magnetic and includes or is made of a magnetic material. In coil component 10, a magnetic field is generated when current is supplied to first planar coil 11 and second planar coil 12. The magnetic field generated by coil component 10 spreads in all directions relative to central axes C1 and C2 of first planar coil 11 and second planar coil 12. Since first magnetic shield member 40 is magnetic, it can direct the spreading magnetic flux lines toward central axes C1 and C2. Coil component 10 may be installed in a vehicle. If the magnetic field generated by coil component 10 flows toward other vehicle components, adverse effects may be caused to the vehicle components. In such cases, first magnetic shield member 40 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0083] The first magnetic shield member 40 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the first magnetic shield member 40 includes a ferrite, preferably a soft ferrite.

[0084] The relative permeability of the first magnetic shield member 40 may be equal to or greater than 500, or may be equal to or greater than 1000. The relative permeability of the first magnetic shield member 40 may be equal to or greater than 500 and equal to or greater than 3000, or may be 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 ambient temperature of 23 degrees.

[0085] (Second magnetic shield member) The second magnetic shield member 50 is provided to cover the first magnetic shield member 40. In the present embodiment, the second magnetic shield member 50 contacts the first magnetic shield member 40. Alternatively, the second magnetic shield member 50 may contact the first magnetic shield member 40 via a spacer. The second magnetic shield member 50 is made of a metallic material and is conductive. Specifically, the second magnetic shield member 50 in the present embodiment is made of aluminum. In this case, leakage of magnetic field from the first planar coil 11 and the second planar coil 12 through the second magnetic shield member 50 is suppressed. The second magnetic shield member 50 may also be made of an aluminum alloy, copper, stainless steel, or the like.

[0086] (Connection terminal) 2 and 3, the first connection terminal 61 is connected to a radially outer end of the turn portion 115 of the first planar coil 11. The second connection terminal 62 is connected to a radially outer end of the turn portion 125 of the second planar coil 12. The first connection terminal 61 and the second connection terminal 62 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 61 and the turn portion 115 and the connection between the second connection terminal 62 and the turn portion 125 may be performed by ultrasonic bonding. However, the connection method is not limited thereto, and for example, a conductive adhesive may be used for connection.

[0087] <Method of manufacturing the coil component 10> Next, a description will be given of an example of a method for manufacturing coil device 10. Fig. 9 is a cross-sectional view showing a state in which first planar coil 11 and molding material 220, which will be described later, are placed in mold 200 for manufacturing coil device 10.

[0088] First, as shown in FIG. 9 , mold 200 is prepared, and first planar coil 11 is placed in mold 200. Mold 200 has concaves and convexes corresponding to the concaves and convexes of contact surface 20S1 of first holding member 20. Specifically, mold 200 includes plate-shaped main body 201 having flat mounting surface 200S on which first planar coil 11 is placed. Main body 201 has protruding portion 202 that protrudes from mounting surface 200S and extends in a spiral shape. Protruding portion 202 is a portion that forms second groove 24 of first holding member 20. First planar coil 11 is placed on mounting surface 200S in a spiral-shaped region that extends along spiral-shaped protruding portion 202. When viewed in the axial direction of first planar coil 11, protruding portion 202 is located between adjacent turn portions of first planar coil 11.

[0089] Also, material 220 for producing first holding member 20 shown in FIGS. 6 to 8 is prepared. In the illustrated example, material 220 is a molding material formed into an overall plate shape. First grooves 25 are formed on one surface of molding material 220. Next, as shown in FIG. 9, molding material 220 is placed on mold 200 and first planar coil 11. At this time, molding material 220 is placed on mold 200 and first planar coil 11 so that the other surface of molding material 220 (the surface opposite to the surface on which first grooves 25 are formed) faces mold 200 and first planar coil 11. Next, first planar coil 11 and molding material 220 are heat-pressed between mold 200 and another mold 210.

[0090] The heat pressing softens and melts molding material 220. As a result, grooves corresponding to protrusions 202 of mold 200 are formed on the other surface of molding material 220. In this manner, first holding member 20 having second grooves 24 is formed. As viewed in the axial direction of first planar coil 11, second grooves 24 are formed between adjacent turn portions of first planar coil 11. Furthermore, first holding member 20 is cooled and solidified, thereby integrating first holding member 20 and first planar coil 11. In this manner, coil intermediate material 10M shown in FIGS. 6 to 8 is produced.

[0091] Next, steps such as integrating second planar coil 12 and second holding member 30 with coil intermediate material 10M are performed, thereby manufacturing coil component 10. In the present embodiment, molding material 220 is melted between dies 200 and 210 by heat pressing to form coil intermediate material 10M in which first planar coil 11 and first holding member 20 are integrated. However, this manufacturing method is merely an example. For example, coil intermediate material 10M may be formed by injecting molding material between dies 200 and 210. Furthermore, when the molding material of first holding member 20 is heat pressed by die 210, first groove 25 may be formed in first holding member 20 by die 210.

[0092] <Applications of coil components> The coil device 10 according to this embodiment can be used as a power transmitting coil in the power transmitting device 1 of the wireless power transmission system S described above, and can also be used as a power receiving coil in the power receiving device 2.

[0093] When coil device 10 is used as a power transmission coil, first connection terminal 61 and second connection terminal 62 are connected to high-frequency current supply unit 1A or an AC power supply as shown in FIG. 1. When high-frequency current is supplied to coil device 10, the current can flow from first connection terminal 61 to first planar coil 11 and second planar coil 12, and then from second connection terminal 62 to high-frequency current supply unit 1A or the AC power supply. Alternatively, the current can flow from second connection terminal 62 to second planar coil 12 and first planar coil 11, and then from first connection terminal 61 to high-frequency current supply unit 1A or the AC power supply. This allows a magnetic field including magnetic field lines along the central axis of the planar coil to be generated.

[0094] On the other hand, when coil device 10 is used as a receiving coil, a high-frequency current can be generated in first planar coil 11 and second planar coil 12 by receiving or generating a magnetic field including magnetic field lines that pass through the inside of first planar coil 11 and second planar coil 12. This high-frequency current can then be supplied to an external device from first connection terminal 61 or second connection terminal 62.

[0095] The coil component 10 can also be used in a transformer, an antenna, etc. For example, when the coil component 10 functions as a primary coil of a transformer, the first connection terminal 61 and the second connection terminal 62 are connected to an AC power source. When a high-frequency current is supplied, magnetic flux can be supplied from the center of the planar coil to the iron core.

[0096] <Modification> Various modifications can be made to the above-described embodiment. For example, coil device 10 includes two planar coils 11 and 12, but is not limited to this. The number of planar coils included in coil device 10 may be one, or may be three or more.

[0097] Furthermore, the coil component 10 includes, but is not limited to, the planar coils 11 and 12, each of which has a rectangular cross section in the direction in which the planar coils 11 and 12 are wound in a spiral shape. The planar coils 11 and 12 do not have to be planar. The coil component 10 may also include a planar coil formed of a Litz wire. A Litz wire is formed by twisting together multiple conductor wires. In this case, the cross section of the planar coil in the direction in which the planar coil is wound in a spiral shape may be circular.

[0098] Furthermore, turn portions 11n of first planar coil 11 are wound around to form a rectangular shape, but are not limited thereto. As shown in FIG. 10 , turn portions 11n may be wound around to form an octagonal shape. More specifically, turn portions 11n may be wound around to form a regular octagonal shape. However, turn portions 11n may be wound around to form a polygonal shape other than an octagonal shape. For example, turn portions 11n may be wound around to form a dodecagonal shape or a regular dodecagonal shape. Similarly, turn portions 12n of second planar coil 12 are wound around to form a rectangular shape, but are not limited thereto. Although not shown, turn portions 12n may be wound around to form an octagonal shape. More specifically, turn portions 12n may be wound around to form a regular octagonal shape. However, turn portions 12n may be wound around to form a polygonal shape other than an octagonal shape. For example, the turn portion 12n may wind around to form a dodecagonal or regular dodecagonal shape.

[0099] Next, the coil intermediate material 10M of the coil device 10 according to this modified example will be described in detail with reference to Fig. 11. Fig. 10 is a plan view of the coil intermediate material 10M. Fig. 11 is a bottom view of the coil intermediate material 10M.

[0100] Hereinafter, the turn portion 11n that is closest to the first central axis C1 may be referred to as the turn portion 1101. Furthermore, the turn portion connected to the turn portion 1101 may be referred to as the turn portion 1102. As shown in FIGS. 10 and 11, in this modification, the turn portions 11n include 12 turn portions 1101 to 1112. Hereinafter, when describing matters common to each of the turn portions 11n, they will basically be referred to as the turn portion 11n.

[0101] The radially inner end (the end closest to the first central axis C1) of the turn portion 1101 closest to the first central axis C1 is electrically connected to the second planar coil 12. On the other hand, the radially outer end (the end farthest from the first central axis C1) of the turn portion 1112 among the plurality of turn portions 11n that is farthest from the first central axis C1 is connected to the first connection terminal 61.

[0102] As shown in FIG. 11 , in this modification, first grooves 25 are formed on the outer surface 20S2. In this modification, the first grooves 25 are also formed to improve the heat dissipation performance of the coil device 10. As shown in FIG. 11 , the first grooves 25 extend in a stripe pattern along a first direction (direction) d1 that is perpendicular to the axial direction. In this case, for example, when the coil device 10 is installed in a vehicle, the coil device 10 is installed in the vehicle so that the first direction d1 is parallel to the vehicle's traveling direction, allowing wind to flow along the first grooves 25. Therefore, the wind can effectively remove heat generated in the coil device 10. The first direction d1 that is perpendicular to the axial direction may be parallel to one side of the rectangle formed by the first holding member 20.

[0103] Here, at least some of the first grooves 25 extend in a direction non-parallel to the extension direction of the turn portion 11n with which at least some of the first grooves 25 overlap, as viewed in the axial direction. That is, as shown in FIG. 11 , the first grooves 25 that overlap the portion 11n2 of the turn portion 11n extending in the second direction d2 extend in a direction (first direction d1) non-parallel to the extension direction of the portion 11n2 (second direction d2). Specifically, the first grooves 25 that overlap the portion 11n2 of the turn portion 11n extending in the second direction d2 extend in the width direction (first direction d1) of the turn portion 11n (portion 11n2). In this case, both ends (both longitudinal ends) of the first grooves 25 that overlap the portion 11n3 may extend along the extension direction of the portion 11n3.

[0104] Furthermore, the first grooves 25 of the turn portion 11n overlapping the portions 11n3 extending in a direction inclined in both the first direction d1 and the second direction d2 extend in a direction (first direction d1) non-parallel to the direction in which the portions 11n3 extend (the direction inclined in both the first direction d1 and the second direction d2). In this case, both ends (longitudinal ends) of the first grooves 25 overlapping the portions 11n3 may extend along the direction in which the portions 11n3 extend.

[0105] On the other hand, the first groove 25 of the turn portion 11n overlapping the portion 11n1 extending in the first direction d1 extends in a direction (first direction d1) parallel to the direction in which the portion 11n1 extends (first direction d1). In this case, both ends (longitudinal ends) of the first groove 25 overlapping the portion 11n1 may extend along the second direction d2, and may have a triangular shape such that both ends protrude outward from the first groove 25, as in the case of the first groove 25a.

[0106] The coil device 10 according to the embodiment described above includes a spiral-shaped planar coil 11 including a first surface 11A and a second surface 11B that are opposite each other in an axial direction extending along a central axis C1 of the spiral shape, a first holding member 20 that overlaps the planar coil 11 so as to face the second surface 11B and holds the planar coil 11, and a second holding member 30 that sandwiches the planar coil 11 between the first holding member 20 and the first holding member 20. The planar coil 11 includes a plurality of turn portions 11n arranged in the radial direction of the planar coil 11. The first holding member 20 has a contact surface 20S1 that contacts the second surface 11B and an outer surface 20S2 opposite the contact surface 20S1. A first groove 25 is formed in the outer surface 20S2. The first groove 25 extends in a stripe pattern along a direction perpendicular to the axial direction. At least a portion of the first grooves 25 extends, as viewed in the axial direction, in a direction non-parallel to the extending direction of the turn portions 11n with which the first grooves 25 overlap. With such a coil device 10, for example, when the coil device 10 is installed in a vehicle, the coil device 10 is installed in the vehicle so that the first direction d1 is parallel to the direction of travel of the vehicle, so that wind flows along the first grooves 25. As a result, the heat generated in the coil device 10 can be effectively removed by the wind.

[0107] In the embodiment described above, the width of the first grooves 25 is 0.8 mm or more and 1.2 mm or less. When the width of the first grooves 25 is 0.8 mm or more, the first grooves 25 can be easily formed. Furthermore, when the width of the first grooves 25 is 1.2 mm or more, the number of first grooves 25 formed on the outer surface 20S2 of the first holding member 20 can be increased. This increases the overall surface area of ​​the first grooves 25 formed on the outer surface 20S2. Therefore, the heat dissipation effect of the first grooves 25 can be further improved.

[0108] In the embodiment described above, the depth of the first grooves 25 is 0.8 mm or more and 1.2 mm or less. When the width of the first grooves 25 is 0.8 mm or more, the surface area of ​​each first groove 25 can be increased. This further improves the heat dissipation effect of the first grooves 25. When the depth of the first grooves 25 is 1.2 mm or less, a decrease in the strength of the first holding member 20 can be suppressed. Furthermore, when the depth of the first grooves 25 is 1.2 mm or less, the first grooves 25 can be easily formed.

[0109] In the embodiment described above, the width of the first grooves 25 is 0.9 to 1.1 times the depth of the first groove. This allows the surface area of ​​each first groove 25 to be increased. This further improves the heat dissipation effect of the first grooves 25. Furthermore, since the width of the first grooves 25 is 0.9 to 1.1 times the depth of the first groove, the first grooves 25 can be easily formed.

[0110] In the embodiment described above, the first grooves 25 do not overlap the second grooves 24 when viewed in the axial direction. This makes it easy to set the depths of the second grooves 24 and the first grooves 25 to desired depths.

[0111] In the embodiment and the modified example described above, the first holding member 20 is non-magnetic and insulating.

[0112] In the embodiment and the modified example described above, the second holding member 30 is magnetic.

[0113] In the embodiment and the modified example described above, the planar coil 11 is formed in a plate shape.

[0114] In the modifications described above, the planar coil 11 is formed using a Litz wire.

[0115] The coil intermediate material 10M according to the embodiment described above includes a spiral-shaped planar coil 11 including a first surface 11A and a second surface 11B that are opposite each other in an axial direction extending along a central axis C1 of the spiral shape, and a first holding member 20 that overlaps the planar coil 11 so as to face the second surface 11B and holds the planar coil 11. The planar coil 11 includes a plurality of turn portions 11n arranged in the radial direction of the planar coil 11. The first holding member 20 has a contact surface 20S1 that contacts the second surface 11B and an outer surface 20S2 opposite the contact surface 20S1. First grooves 25 are formed on the outer surface 20S2. The first grooves 25 extend in a striped pattern in a direction perpendicular to the axial direction. At least a portion of the first grooves 25 extends in a direction non-parallel to the direction in which the turn portions 11n overlapping the first grooves 25 extend, as viewed in the axial direction. According to such a coil intermediate material 10M, when the coil component 10 made of the coil intermediate material 10M is installed in a vehicle, for example, the coil component 10 is installed in the vehicle so that the first direction d1 is parallel to the direction of travel of the vehicle, so that wind flows along the first grooves 25. Therefore, the heat generated in the coil component 10 can be effectively removed by the wind.

[0116] The power transmitting device 1 and / or the power receiving device 2 according to the embodiment and its modification described above includes the coil component 10 described above.

[0117] The power transmission system S according to the embodiment and its modification described above includes a power transmitting device 1 and a power receiving device 2. At least one of the power transmitting device 1 and the power receiving device 2 includes the coil component 10 described above.

[0118] Although several modifications of the above-described embodiment have been described, it is of course possible to combine a plurality of modifications as appropriate. [Explanation of symbols]

[0119] 1 Power transmission equipment 1A high frequency current supply 2. Power receiving device 2A conversion unit 10 Coil parts 10M coil intermediate material 10MR area 11 First planar coil 11A First Side 11B Second Side 11E Conductor 11n Turn section 11n1 part 11n2 part 12 Second planar coil 12A First Side 12B Second Side 12E Conductor 12n Turn section 20 First holding member 20R1 area 20R2 area 20S1 Contact surface 20S2 External surface 24 Second Groove 25 First Groove 30 second holding member 31 Base 32 Protrusion 33 Spacer part 40 First magnetic shield member 50 second magnetic shield member 61 First connection terminal 62 Second connection terminal 200 molds 200S installation surface 201 Main body part 202 Convex part 210 Other molds 220 Molding materials C1 1st center axis C2 2nd central axis S Power Transmission System

Claims

1. a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the second surface and holds the planar coil; a second holding member that sandwiches the planar coil between the first holding member and the second holding member, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, the first holding member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, a first groove formed in the outer surface; the first grooves extend in a stripe shape along a direction perpendicular to the axial direction, a coil component in which at least some of the first grooves extend in a direction non-parallel to a direction in which the turn portions overlapping with the at least some of the first grooves extend, as viewed in the axial direction.

2. the second holding member has a protrusion extending along the axial direction between adjacent turn portions of the planar coil, a second groove formed in the contact surface to receive the protrusion; The coil component according to claim 1 , wherein the first groove does not overlap with the second groove when viewed in the axial direction.

3. The coil component according to claim 1 , wherein the width of the first groove is not less than 0.8 mm and not more than 1.2 mm.

4. The coil component according to claim 1 , wherein the first groove has a depth of 0.8 mm or more and 1.2 mm or less.

5. The coil component according to claim 1 , wherein the width of the first groove is 0.9 to 1.1 times the depth of the first groove.

6. The coil component according to claim 1 , wherein the first holding member is non-magnetic and insulating.

7. The coil component according to claim 1 , wherein the second holding member is magnetic.

8. The coil component according to claim 1 , wherein the planar coil is formed in a plate shape.

9. The coil component according to claim 1 , wherein the planar coil is formed using a Litz wire.

10. a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the second surface and holds the planar coil, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, the first holding member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, a first groove formed in the outer surface; the first grooves extend in a stripe shape along a direction perpendicular to the axial direction, A coil intermediate material, wherein at least some of the first grooves extend in a direction non-parallel to a direction in which the turn portions overlapping with the at least some of the first grooves extend, as viewed in the axial direction.

11. A power transmitting device comprising the coil component according to claim 1 .

12. A power receiving device comprising the coil component according to claim 1 .

13. The power transmission device includes a power receiving device. 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 .

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