Coil components, coil intermediate materials, power transmission equipment, power receiving equipment, and power transmission systems

Abstract

To provide a coil component, a coil intermediate material, a power transmission device, a power reception device and a power transmission system which reduce a warp of a holding member that holds a coil.SOLUTION: A coil component 10 comprises: a first planar coil 11 which has the spiral shape; a first holding member 20 which holds the first planar coil; and a second holding member 30 which sandwiches the first planar coil between the first holding member and itself and is integrated with them. The second holding member has a protruding part 32 which extends along the axial direction between adjacent turn parts of the first planar coil. The first holding member includes a contact surface 20S1 which contacts the first planar coil and an outer surface 20S2 on the opposite side of the contact surface. A first groove 24 which receives the protruding part 32 is formed on the contact surface. A second groove 25 is formed on the outer surface. The second groove is formed in a region 20R2 on the outer surface overlapping with a first centerline axis C1 of the first planar coil and a region 20R1 on the contact surface including the first groove when viewed in the axial direction of the first planar coil.SELECTED DRAWING: Figure 4

Description

[[Technical Field]]

[0001] The present disclosure relates to a coil component, an intermediate coil product, a power transmission device, a power reception device, and a power transmission system. [[Background Art]]

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

[0003] When power is transmitted in a contactless manner, a high-frequency current flows through a resonance circuit including a coil. The coil may be formed in a spiral shape, for example, as disclosed in Patent Document 1. Generally, a coil is used while housed in a hollow case. [[Prior Art Documents]] [[Patent Documents]]

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

[0005] By the way, studies have been made on forming a case integrally with a coil and causing the case to hold the coil. In other words, studies have been made on forming 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 shapes of the coil and other components attached to the coil. For example, when the coil is formed in a spiral shape, as shown in Patent Document 1, a magnetic body is arranged between adjacent portions of the coil. For this reason, a groove for accommodating the tip end of the magnetic body is formed on the inner surface of the holding member.

[0006] Such retaining members can be manufactured using thermoplastic or thermosetting materials. Specifically, the aforementioned retaining member can be manufactured by heating and melting the material, fitting it into a mold having irregularities corresponding to the irregularities on the inner surface of the retaining member, and then cooling it. However, retaining members manufactured in this manner may warp.

[0007] The embodiments of this disclosure aim to reduce the warping of a retaining member that holds a coil. [Means for solving the problem]

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

[20] .

[0009] [1] A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, A first holding member overlaps the planar coil so as to face the second surface and holds the planar coil, The planar coil is sandwiched between the planar coil and the first holding member, and a second holding member is integrated with the planar coil and the first holding member, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The second retaining member has a projection that extends along the axial direction between adjacent turn portions of the planar coil, The first retaining member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, A first groove for receiving the protrusion is formed on the contact surface. A second groove is formed on the outer surface, A coil component wherein the second groove is formed in a region on the outer surface that overlaps with the region on the contact surface including the central axis and the first groove when viewed in the axial direction.

[0010] [2] The coil component according to [1], wherein the second groove is formed along the spiral shape of the planar coil when viewed in the axial direction.

[0011] [3] The coil component according to [1] or [2], wherein the width of the second groove is 0.2 to 1.1 times the width of the first groove.

[0012] [4] The coil component according to any one of [1] to [3], wherein the depth of the second groove is 0.2 to 1.1 times the depth of the first groove.

[0013] [5] The coil component according to any one of [1] to [4], wherein the volume of the second groove is 0.2 to 1.1 times the volume of the first groove.

[0014] [6] The coil unit according to any one of [1] to [5], wherein the second groove does not overlap with the first groove when viewed in the axial direction.

[0015] [7] A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, A first holding member overlaps the planar coil so as to face the second surface and holds the planar coil, The planar coil is sandwiched between the planar coil and the first holding member, and a second holding member is integrated with the planar coil and the first holding member, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The second retaining member has a projection that extends along the axial direction between adjacent turn portions of the planar coil, The first retaining member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, A first groove for receiving the protrusion is formed on the contact surface. At least one rib is formed on the outer surface, The coil component, wherein the at least one rib is formed in a region on the outer surface that overlaps a region on the contact surface including the central axis and the first groove when viewed in the axial direction.

[0016] [8] The coil component according to [7], wherein the at least one rib includes a plurality of ribs extending along directions intersecting each other.

[0017] [9] The at least one rib includes a plurality of ribs, The coil component according to [7] or [8], wherein the plurality of ribs are formed in a grid pattern when viewed in the axial direction.

[0018]

[10] The coil component according to any one of [1] to [9], wherein the first holding member is non-magnetic and insulating.

[0019]

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

[10] , wherein the second holding member has magnetism.

[0020]

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

[11] , wherein the planar coil is formed in a plate shape.

[0021]

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

[11] , wherein the planar coil is formed using a litz wire.

[0022]

[14] a planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in an axial direction extending along the central axis of the spiral shape; a first holding member overlapping the planar coil so as to face the second surface and holding the planar coil, wherein the planar coil includes a plurality of turn parts arranged in a radial direction of the planar coil, The first retaining member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, A first groove is formed on the contact surface, A second groove is formed on the outer surface, The first groove is formed along the spiral shape of the planar coil between adjacent turn portions of the planar coil when viewed in the axial direction. The coil intermediate material is formed in a region on the outer surface that overlaps with the region on the contact surface including the central axis and the first groove when viewed in the axial direction.

[0023]

[15] The coil intermediate material according to

[14] , wherein the second groove is formed along the spiral shape of the planar coil when viewed in the axial direction.

[0024]

[16] A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, The device comprises a first holding member that overlaps with the planar coil so as to face the second surface and holds the planar coil, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The first retaining member has a contact surface that contacts the second surface and an outer surface opposite to the contact surface, A first groove is formed on the contact surface, At least one rib is formed on the outer surface, The first groove is formed along the spiral shape of the planar coil between adjacent turn portions of the planar coil when viewed in the axial direction. A coil intermediate material wherein the at least one rib is formed in a region on the outer surface that overlaps with a region on the contact surface including the central axis and the first groove when viewed in the axial direction.

[0025]

[17] The coil intermediate material according to

[16] , wherein the at least one rib includes a plurality of ribs extending in directions intersecting each other.

[0026]

[18] A power transmission device comprising a coil component as described in any of [1] to

[13] .

[0027]

[19] A power receiving device comprising a coil component as described in any of [1] to

[13] .

[0028]

[20] It comprises a power transmission device and a power receiving device, A power transmission system in which at least one of the power transmission device and the power receiving device comprises a coil component as described in any of [1] to

[13] . [Effects of the Invention]

[0029] According to one embodiment of the present disclosure, the warping of the holding member that holds the coil can be reduced. [Brief explanation of the drawing]

[0030] [Figure 1] Figure 1 is a schematic diagram showing a wireless power transmission system to which a coil unit according to one embodiment may be applied. [Figure 2] Figure 2 is a plan view of a coil component according to one embodiment. [Figure 3] Figure 3 is an exploded perspective view of the coil component shown in Figure 2. [Figure 4] Figure 4 is a cross-sectional view of the coil component shown in Figure 2. [Figure 5] Figure 5 is a perspective view of the coil intermediate material shown in Figure 4, viewed from the side of the planar coil. [Figure 6] Figure 6 is a perspective view of the coil intermediate material shown in Figure 5, viewed from the outer surface side of the first retaining member. [Figure 7] Figure 7 is a plan view of the coil intermediate material shown in Figure 6. [Figure 8] Figure 8 is a perspective view showing a mold for molding the first retaining member shown in Figures 6 and 7. [Figure 9]Figure 9 is a cross-sectional view illustrating an example of a manufacturing method for the coil component shown in Figure 2. [Figure 10] Figure 10 is a diagram illustrating a modified coil component, and is a plan view showing the outer surface of the first retaining member. [Figure 11] Figure 11 shows a cross-section of the first retaining member along the line XI-XI in Figure 10. [Figure 12] Figure 12 shows a cross-section of the first retaining member along the line XII-XII in Figure 10. [Modes for carrying out the invention]

[0031] The embodiments will be described below with reference to the drawings. Note that, for the sake of illustration and ease of understanding, the scale and aspect ratios of the drawings attached to this specification have been appropriately altered and exaggerated from those of the actual objects.

[0032] Furthermore, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from each other solely based on differences in name. Therefore, for example, "sheet" is a concept that includes components that could also be called films or plates.

[0033] <Wireless Power Transmission System> Figure 1 schematically shows a wireless power transmission system S to which a coil component 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 Figure 1. It goes without saying that a coil component other than the coil component 10 according to this embodiment may be applied to the power transmission system S.

[0034] <Wireless Power Transmission System> The power transmission system S comprises a power transmission device 1 and a power receiving device 2. The power transmission device 1 includes a coil component 10 and a high-frequency current supply unit 1A. The coil component 10 in the power transmission device 1 functions as a power transmission coil component. The high-frequency current supply unit 1A supplies high-frequency current to the coil component 10 as a power transmission coil component.

[0035] 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 has a rectifier circuit and the like that converts the high-frequency current into a DC current. The conversion unit 2A may include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0036] In this embodiment, both the power transmission device 1 and the power receiving device 2 include a coil component 10. However, the coil component 10 may be used in only one of the power transmission device 1 or the power receiving device 2, while a different type of coil component is used in the other.

[0037] When transmitting power wirelessly (contactlessly) from the power transmission device 1 to the power receiving device 2, the power transmission device 1 supplies a high-frequency current of a predetermined frequency to the coil component 10, which acts as a power transmission coil component, from the high-frequency current supply unit 1A. At this time, a magnetic field is generated in the coil component 10 due to electromagnetic induction. Due to the influence of this magnetic field, a high-frequency current is generated in the coil component 10, which acts as a power receiving coil component, in the power receiving device 2. That is, the power receiving device 2 receives a magnetic field from the power transmission device 1 or is influenced by the magnetic field and causes a high-frequency current to flow due to electromagnetic induction. The conversion unit 2A converts this high-frequency current into a DC current and supplies the converted DC current to, for example, a battery (not shown).

[0038] The power transmission system S shown in Figure 1 employs a magnetic resonance method as the power transmission method. However, the coil component 10 in this embodiment may also be used in an electromagnetic induction power transmission system. Furthermore, the power transmission system S is configured as a system for wirelessly transmitting power to an electric vehicle. In this case, the power transmission device 1 is installed on a road, parking lot, etc. The power receiving device 2 is installed in the electric vehicle.

[0039] However, the applications of the power transmission system S are 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. Furthermore, the power transmission system S may be used to transmit power to submersibles and exploration robots underwater. Also, the applications of the coil component 10 are not limited to wireless power transmission systems. For example, the coil component 10 may be used in transformers, DC-DC converters, antennas, etc.

[0040] <Coil components> The coil component 10 will be described below. Figure 2 is a plan view of the coil component 10. Figure 3 is an exploded perspective view of the coil component 10. Figure 4 is a cross-sectional view of the coil component 10 along the central axes C1 and C2 of the planar coils 11 and 12, which will be described later.

[0041] As shown in Figures 2 to 4, the coil component 10 comprises a first planar coil 11, a second planar coil 12, a first retaining member 20, a second retaining member 30, a first magnetic shielding member 40, a second magnetic shielding member 50, a first connection terminal 61, and a second connection terminal 62.

[0042] As shown in Figure 3, in the coil component 10, the first planar coil 11, the second planar coil 12 and the second holding member 30, the first magnetic shielding member 40, and the second magnetic shielding member 50 are superimposed on the first holding member 20 in this order. In Figure 2, for the sake of explanation, the second holding member 30, the first magnetic shielding member 40, and the second magnetic shielding member 50 are omitted from the illustration, but in reality, the second holding member 30, the first magnetic shielding member 40, and the second magnetic shielding member 50 are superimposed on the second planar coil 12, which is shown by a solid line. Also, in Figure 2, for the sake of explanation, the first planar coil 11 is shown by a dashed line. Furthermore, in Figures 2 and 3, the first connection terminal 61 and the second connection terminal 62 are simply shown by dashed lines. The parts of the coil component 10 will be described in detail below.

[0043] (First planar coil and second planar coil) The first planar coil 11 is spiral-shaped and formed from a conductive material. In this embodiment, the first planar coil 11 contains copper. Specifically, the first planar coil 11 is formed from copper. However, the first planar coil 11 may be formed from a copper alloy, aluminum, aluminum alloy, or the like.

[0044] As shown in Figure 3, the first planar coil 11 is plate-shaped, and as shown in Figure 4, the cross-sectional shape of the first planar coil 11 in the direction perpendicular to the direction in which it circulates in a spiral shape, or in other words, the direction in which it extends in a spiral shape, is rectangular.

[0045] The symbol C1 shown in Figures 2 to 4 indicates the first central axis of the first planar coil 11, which passes through the center of the spiral shape of the first planar coil 11. Hereinafter, when referring to the axial direction of the first planar coil 11, that direction means the direction extending along the first central axis C1 or the direction parallel to the first central axis C1. Furthermore, the radial direction of a circle drawn on a plane perpendicular to the first central axis C1, with any point on the first central axis C1 as the center, is referred to as the radial direction of the first planar coil 11. The first planar coil 11 includes a first surface 11A and a second surface 11B that are opposite to each other in the axial direction. The first planar coil 11 has the second planar coil 12 superimposed on the first surface 11A, and faces the first holding member 20 at the second surface 11B.

[0046] As shown in Figure 3, the first planar coil 11 has a conductor 11E that forms a spiral shape with a plurality of turned portions 11n. The plurality of turned portions 11n of the first planar coil 11 are arranged in a direction perpendicular to the first central axis C1 of the spiral shape. Specifically, the plurality of turned portions 11n are connected so as to move radially outward from the first central axis C1 of the spiral shape toward the first planar coil 11, gradually moving away from the first central axis C1. This forms the spiral shape.

[0047] The turn section 11n basically has a shape in which the linear conductor portion does not form a ring but rotates 360 degrees around the first central axis C1. In the case of a so-called planar coil, both ends of the turn section 11n are offset in the radial direction of the first planar coil 11. In the case of multiple turn sections 11n, the radially inward end of one turn section 11n is connected to the radially outward end of another turn section 11n, and the other turn sections 11n extend away from the first central axis C1.

[0048] In the following, the turn section 11n closest to the first central axis C1 may be referred to as turn section 111. The turn section connected to turn section 111 may be referred to as turn section 112. In this embodiment, the multiple turn sections 11n include five turn sections 111 to 115. When describing matters common to each of the multiple turn sections 11n in the following, they will generally be referred to as turn section 11n.

[0049] In this embodiment, the turn section 11n rotates in a rectangular shape. However, the turn section 11n may also rotate in a circular shape. In this specification and disclosure, the spiral shape refers to the shape of a spirally wound planar curve. The planar curve referred to here also includes a planar pattern that repeatedly rotates while bending in a broken line shape, as shown in the figure. In other words, the spiral shape refers to the shape of a planar curve that moves away from the center (or approaches the center) as it rotates.

[0050] The radially inward end (the end closest to the first central axis C1) of the turn section 111 closest to the first central axis C1 is electrically connected to the second planar coil 12. On the other hand, the radially outward end (the end moving away from the first central axis C1) of the turn section 115, which is furthest from the first central axis C1 among the multiple turn sections 11n, is connected to the first connection terminal 61.

[0051] Here, the radially inward direction of the first planar coil 11 (turn portion 11n) means the direction approaching the first central axis C1 in that radial direction. The radially outward direction of the first planar coil 11 (turn portion 11n) means the direction away from the first central axis C1 in that radial direction. Furthermore, the first central axis C1 is determined in this embodiment as follows. First, linear virtual turn portions similar in shape to the innermost turn portion 111 are sequentially drawn radially inward, forming a spiral shape, starting from the radially inward end of the innermost turn portion 111. Drawing is continued until a virtual turn portion that fits within a diameter of 1 cm can be drawn. Then, the line passing through the radially inward 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 the first central axis C1.

[0052] In this embodiment, the first planar coil 11 is formed, for example, by punching a spiral shape out of a copper plate. However, the first planar coil 11 can also be formed by etching a spiral shape out of copper foil.

[0053] The thickness of the first planar coil 11 (thickness of the conductor 11E) may be, for example, 0.1 mm or more and 1.0 mm or less. The radius of the first planar coil 11 (distance from the first central axis C1 to the part furthest in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less. The aspect ratio of the first planar coil 11 (conductor 11E) with a rectangular cross-sectional shape is determined by dividing the radial width of the first planar coil 11 (conductor 11E) by the thickness of the first planar coil 11 (conductor 11E). The aspect ratio of the first planar coil 11 (conductor 11E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0054] When transmitting power to an electric vehicle using a magnetic resonance method, it is desirable to be able to transmit power of 1kW or more, preferably 5kW or more, in the high-frequency current frequency band of 10kHz to 200kHz, particularly between 75kHz and 100kHz, and even further between 79kHz and 90kHz. In this case, the thickness of the first planar coil 11, which is made of copper, is preferably 0.2mm or more. From this viewpoint, the lower limit of the thickness of the first planar coil 11 may be set to 0.2mm. Also, when transmitting power to an electric vehicle, excessively large size is undesirable and the size may be limited. From this viewpoint, it is preferable that the first planar coil 11 and the second planar coil 12 described later, more specifically the conductor 11E of the first planar coil 11 and the conductor 12E of the second planar coil 12, are formed to a size that fits within a square with sides of 800mm.

[0055] Furthermore, the wire width of the first planar coil 11 (wire width of the conductor 11E), that is, the radial width of each turn portion 11n (width in the radial direction), is not particularly limited. However, considering the ability to transmit power of 1kW or more, preferably 5kW or more, in the high-frequency current frequency band of 79kHz to 90kHz, for example, the radial width of the turn portion 11n may be 2mm to 20mm, 2mm to 16mm, 2mm to 12mm, or 2mm to 8mm. Also, the number of turns of the first planar coil 11 may be 4 to 12, but is not particularly limited.

[0056] Next, the second planar coil 12 is also spiral-shaped, and in this embodiment, the second planar coil 12 also contains copper. More specifically, the second planar coil 12 is formed from copper. The material of the second planar coil 12 is not particularly limited and may be a copper alloy, aluminum, aluminum alloy, etc. Also, the second planar coil 12 is plate-shaped, and as shown in Figure 4, the cross-sectional shape of the second planar coil 12 in a direction perpendicular to the direction in which the second planar coil 12 circulates in a spiral shape is rectangular.

[0057] The symbol C2 shown in Figures 2 to 4 indicates the second central axis of the second planar coil 12, which passes through the center of the spiral shape of the second planar coil 12. Hereinafter, when referring to the axial direction of the second planar coil 12, that direction means the direction extending along the second central axis C2 or the direction parallel to the second central axis C2. Furthermore, the radial direction of a circle drawn on a plane perpendicular to the second central axis C2, with an arbitrary point on the second central axis C2 as the center, is referred to as the radial direction of the second planar coil 12. The second planar coil 12 includes a first surface 12A and a second surface 12B that are opposite to each other in the axial direction. The second planar coil 12 has the second holding member 30, the first magnetic shielding member 40 and the second magnetic shielding member 50 superimposed on the first surface 12A, and faces the first planar coil 11 (first surface 11A) at the second surface 12B.

[0058] In this embodiment, the second planar coil 12 is arranged to be coaxial with the first planar coil 11. That is, the first central axis C1 of the first planar coil 11 and the second central axis C2 of the second planar coil 12 coincide, or in other words, they are located on the same straight line. However, the first planar coil 11 and the second planar coil 12 may overlap such that the first central axis C1 of the first planar coil 11 and the second central axis C2 of the second planar coil 12 are parallel to each other. In other words, the first planar coil 11 and the second planar coil 12 do not have to be coaxial.

[0059] The second planar coil 12 also has a conductor 12E that forms a spiral shape with multiple turned portions 12n. The multiple turned portions 12n of the second planar coil 12 are arranged in a direction perpendicular to the second central axis C2 of the spiral shape.

[0060] The connection configuration of the multiple turn sections 12n and the designations according to their position (e.g., turn section 121) are the same as those of the turn section 11n of the first planar coil 11. In this embodiment, the number of turns of the first planar coil 11 and the second planar coil 12 are the same, and the multiple turn sections 12n include five turn sections 121 to 125. Also, the turn sections 12n circulate in a rectangular shape, similar to the turn sections 11n. However, the turn sections 12n may also circulate in a circular shape. Furthermore, the number of turns of the first planar coil 11 and the second planar coil 12 may be different. Also, for example, the turn section 12n may be rectangular and the turn section 11n may be circular.

[0061] Furthermore, as described above, the radially inner end of the turn section 111 closest to the first central axis C1 is electrically connected to the second planar coil 12. More specifically, the radially inner end of the turn section 111 is connected to the radially inner end of the turn section 121 in the second planar coil 12. When the first planar coil 11 and the second planar coil 12 are connected, the direction in which the first planar coil 11 circulates from the end not connected to the second planar coil 12 (the radially outer end of the turn section 115) to the end connected to the second planar coil 12 is the same as the direction in which the second planar coil 12 circulates from the end connected to the first planar coil 11 to the end not connected to the first planar coil 11 (the radially outer end of the turn section 125).

[0062] Furthermore, the radially outer end of the turn portion 125, which is furthest from the second central axis C2 among the multiple turn portions 12n, is connected to the second connecting terminal 62. The radially inward and outward directions of the second planar coil 12 (turn portion 12n) are determined in the same way as the radially inward and outward directions of the first planar coil 11 described above. The position of the second central axis C2 is also determined in the same way as the first central axis C1. In this embodiment, the second planar coil 12 is also formed by punching a spiral shape out of a copper plate, for example. However, the second planar coil 12 can also be formed by etching a spiral shape out of copper foil.

[0063] In this embodiment, the thickness of the second planar coil 12 (thickness of the conductor 12E) may be, for example, 0.1 mm or more and 1.0 mm or less. Also, the radius of the second planar coil 12 (distance from the second central axis C2 to the part furthest 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 the first planar coil 11. Also, the aspect ratio of the second planar coil 12 (conductor 12E) with a rectangular cross-sectional shape may be 2 or more and 12 or 3 or more and 10 or less, as in the case of the first planar coil 11. Also, the wire width of the second planar coil 12 (wire width of the conductor 12E), that is, the radial width of each turn portion 12n (width in the radial direction), may be 2 mm or more and 20 mm or less, or 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. Furthermore, the number of turns of the second planar coil 12 may be between 4 and 12, but is not particularly limited.

[0064] Furthermore, as shown in Figure 4, the first planar coil 11 and the second planar coil 12 overlap with a gap in their axial direction. This gap may be between 0.5 mm and 1.5 mm. The dimensions of the gap are not particularly limited, but if the gap is too small, the eddy current loss generated in the first planar coil 11 and the second planar coil 12 when current is supplied tends to increase. Also, if the gap is too large, the thinning of the coil component 10 is impaired. The gap between the first planar coil 11 and the second planar coil 12 is maintained by the interposition of the second holding member 30 between the planar coils 11 and 12, as will be described later.

[0065] (First retaining member) The first holding member 20 overlaps with the first planar coil 11 so as to face the second surface 11B of the first planar coil 11, and holds the first planar coil 11. In the coil component 10, for example when transmitting power, the magnetic field generated by the first planar coil 11 and the second planar coil 12 is passed through the first holding member 20. Therefore, it is preferable that the first holding member 20 is non-conductive (insulating) and non-magnetic in order to not obstruct the magnetic field and to prevent the generation of eddy currents.

[0066] Considering the preference for non-conductive (insulating) and non-magnetic properties, the material of the first retaining member 20 may be, for example, a resin, or a fiber-reinforced plastic. More specifically, the material of the first retaining member 20 may be glass fiber-reinforced polyamide. However, the material of the first retaining member 20 is not particularly limited. For example, it may not contain glass fibers. Also, thermoplastic resins or thermosetting resins other than polyamide may be used. Note that insulating properties refer to a volume resistivity of 10 10 This means it is greater than or equal to Ω·m. Non-magnetic means it does not exhibit magnetism.

[0067] The first holding member 20 holds the first planar coil 11 by being integrated with it. In this embodiment, after placing the first planar coil 11 in a mold 200 for forming the first holding member (see Figure 8), the material for creating the first holding member is pressed into the mold 200 by a hot press and molded, and then cooled and solidified so that the first planar coil 11 and the first holding member 20 are integrated. In this specification, the first holding member 20 integrated with the first planar coil 11 is also referred to as the coil intermediate material 10M.

[0068] In this embodiment, the first retaining member 20 sandwiches the first planar coil 11 and the second planar coil 12 together with the second retaining member 30. The first retaining member 20 has a contact surface 20S1 that contacts the second surface 11B of the first planar coil 11. The contact surface 20S1 forms the inner surface of the first retaining member 20. The first retaining member 20 also has an outer surface 20S2 which is the surface opposite to the contact surface 20S1.

[0069] As shown in Figures 4 and 5, a first groove 24 is formed in the contact surface 20S1 to receive the protrusion 32 of the second holding member 30, which will be described later. Also, as shown in Figures 4 and 6, a second groove 25 is formed in the outer surface 20S2. The first groove 24 and the second groove 25 will be described in detail later.

[0070] (Second retaining member) In this embodiment, as shown in Figure 4, the second retaining member 30 is integrated with the first planar coil 11, the second planar coil 12, and the first retaining member 20 by sandwiching the first planar coil 11 and the second planar coil 12 between the first retaining member 20. As described above, the second retaining member 30 is interposed in part between the second planar coil 12 and the first magnetic shielding member 40, while another part is interposed between the first planar coil 11 and the second planar coil 12.

[0071] More specifically, the second holding member 30 has a base portion 31 interposed between the second planar coil 12 and the first magnetic shielding member 40, and a projection portion 32 projecting from the base portion 31 toward the first holding member 20. The base portion 31 covers the entire first surface 12A of the second planar coil 12. When viewed in the axial direction of the first planar coil 11 and the second planar coil 12, the base portion 31 is formed to be large enough to encompass the entirety of the first planar coil 11 and the second planar coil 12. The base portion 31 and the first holding member 20 sandwich the first planar coil 11 and the second planar coil 12 between them.

[0072] The projection 32 extends along the axial direction of the first planar coil 11, between adjacent turns of the first planar coil 11. Therefore, the projection 32 is formed along the spiral shape of the first planar coil 11. In the illustrated example, the projection 32 is formed in a spiral shape corresponding to the spiral shape of the first planar coil 11. As described above, the projection 32 is received in the first groove 24 of the first retaining member 20. In other words, the projection 32 is filled in the first groove 24 of the first retaining member 20.

[0073] In the illustrated example, the second retaining member 30 further includes a spacer portion 33 positioned between the first planar coil 11 and the second planar coil 12. The spacer portion 33 maintains the gap between the first planar coil 11 and the second planar coil 12. In other words, the second planar coil 12 is embedded in the second retaining member 30. The portion of the second retaining member 30 that covers the second surface 12B of the second planar coil 12 is the spacer portion 33. The spacer portion 33 contacts the first surface 11A of the first planar coil 11.

[0074] The second retaining member 30 as a whole is magnetic, that is, the base portion 31, the protruding portion 32, and the spacer portion 33 are each magnetic. The second retaining member 30 improves coil performance by suppressing eddy current losses and leakage flux through magnetism and by increasing the coupling coefficient. The relative permeability of the second retaining member 30 is preferably 2.0 or higher, and may be between 2.0 and 10.0. The relative permeability of the second retaining member 30 is more preferably 5.0 or higher, and may be between 5.0 and 10.0. The relative permeability of the second retaining member 30 is not particularly limited, but if it is too high, the flexibility and strength of the second retaining member 30 may be undesirably impaired. Therefore, the relative permeability of the second retaining member 30 may be 200 or less.

[0075] Furthermore, the coil performance can be effectively improved by providing the protrusion 32 to the second holding member 30. The height of the protrusion 32 (the distance between the top of the protrusion 32 and the second surface 11B of the first planar coil 11, along the axial direction of the first planar coil 11) is not particularly limited, but may be 0.5 mm or more, or 1.0 mm or more. The higher the height of the protrusion 32, the greater the effect of suppressing eddy current loss and the higher the coupling coefficient tends to be. On the other hand, the higher the protrusion 32, the more prone it is to break starting from the base. Therefore, the height of the protrusion 32 may be 10 mm or less, for example.

[0076] In this embodiment, the second retaining member 30 includes, for example, a resin and a plurality or countless magnetic particles composed of a magnetic material. The magnetic particles are held by the resin, which serves as the retaining material.

[0077] The magnetic particles may be formed from one or more of the following: ferrite, particularly soft magnetic materials such as ferrite, nanocrystalline magnetic materials, silicon steel, electromagnetic soft iron, and amorphous metals. The resin used as the holding material may be glass fiber reinforced polyamide. That is, the resin may be formed from a material containing polyamide as a thermoplastic resin (thermoplastic material) and glass fibers. However, the molding material for the second holding member 30 is not particularly limited.

[0078] (First groove) As described above, the first groove 24 of the first retaining member 20 receives the protrusion 32 of the second retaining member 30. As shown in Figure 4, the protrusion 32 is formed in a region on the second retaining member 30 that overlaps with a region 10MR on the coil intermediate material 10M, which includes the first planar coil 11 and its central axis C1, when viewed in the axial direction of the first planar coil 11. For this reason, the first groove 24 is also formed in a region 20R1 on the contact surface 20S1, which corresponds to the region 10MR. In the illustrated example, when viewed in the axial direction of the first planar coil 11, the region 10MR on the coil intermediate material 10M and the region 20R1 on the contact surface 20S1 overlap.

[0079] Furthermore, in the illustrated example, the protrusion 32 is formed along the spiral shape of the first planar coil 11. Therefore, the first groove 24 is also formed along the spiral shape of the first planar coil 11 (see Figure 5).

[0080] (The second rift) The second groove 25 is formed for the purpose of suppressing warping of the first retaining member 20. According to the inventor's findings, warping of the first retaining member 20 occurs when the first retaining member 20, which has been heated and molded in the mold 200, cools and solidifies. This is thought to be because, when the first retaining member 20 cools, the degree of shrinkage of the first retaining member 20 differs between the contact surface 20S1 side and the outer surface 20S2 side. Furthermore, the reason why the degree of shrinkage of the first retaining member 20 differs between the contact surface 20S1 side and the outer surface 20S2 side is thought to be because the amount of material forming the first retaining member 20 differs between the contact surface 20S1 side and the outer surface 20S2 side of the first retaining member 20. In other words, the first groove 24 is formed on the contact surface 20S1 of the first retaining member 20. Therefore, if grooves are not formed on the outer surface 20S2 of the first retaining member 20, the amount of material on the contact surface 20S1 side of the first retaining member 20 will be at least as much as the volume of the first groove 24 compared to the amount of material on the outer surface 20S2 side. Accordingly, in this embodiment, it is considered that by forming a second groove 25 on the outer surface 20S2, the difference between the amount of material on the contact surface 20S1 side and the amount of material on the outer surface 20S2 side can be reduced, thereby suppressing warping of the first retaining member 20.

[0081] Preferably, the second groove 25 is formed in a region 20R2 on the outer surface 20S2 that corresponds to a region 20R1 on the contact surface 20S1 where the first groove 24 is formed. This makes it possible to reduce the difference between the degree of contraction of the first retaining member 20 in each region on the contact surface 20S1 and the degree of contraction of the first retaining member 20 in each region on the outer surface 20S2 corresponding to each region, thereby effectively suppressing warping of the first retaining member 20. In the illustrated example, when viewed in the axial direction of the first planar coil 11, the region 20R1 on the contact surface 20S1 and the region 20R2 on the outer surface 20S2 overlap (see Figure 4). That is, the second groove 25 is formed in a region 20R2 on the outer surface 20S2 that overlaps with the region 20R1 on the contact surface 20S1 including the central axis C1 and the first groove 24 when viewed in the axial direction of the first planar coil 11 (see Figures 4 and 6).

[0082] Furthermore, in the illustrated example, the second groove 25 is formed along the spiral shape of the first planar coil 11 when viewed in the axial direction of the first planar coil 11 (see Figures 6 and 7). This effectively reduces the difference between the degree of contraction of the first retaining member 20 in each region on the contact surface 20S1 and the degree of contraction of the first retaining member 20 in each region on the outer surface 20S2 corresponding to each region. Furthermore, in the illustrated example, since the first groove 24 is formed in a spiral shape corresponding to the spiral shape of the first planar coil 11, the second groove 25 is also formed in a spiral shape corresponding to the spiral shape of the first planar coil 11.

[0083] The width of the second groove 25 is not particularly limited, but for example, it is 0.2 to 1.1 times the width of the first groove 24. This effectively suppresses the warping of the first retaining member 20. In the illustrated example, the width of the second groove 25 is substantially equal to the width of the first groove 24. Specifically, the width of the second groove 25 is 0.9 to 1.1 times the width of the first groove 24. This further effectively suppresses the warping of the first retaining member 20.

[0084] Furthermore, the depth of the second groove 25 is not particularly limited, but for example, it is 0.2 to 1.1 times the depth of the first groove 24. This effectively suppresses warping of the first retaining member 20. In the illustrated example, the depth of the second groove 25 is substantially equal to the depth of the first groove 24. Specifically, the depth of the second groove 25 is 0.9 to 1.1 times the depth of the first groove 24. This also further effectively suppresses warping of the first retaining member 20.

[0085] Furthermore, the volume of the second groove 25 is not particularly limited, but for example, it is 0.2 to 1.1 times the volume of the first groove 24. This effectively suppresses the warping of the first retaining member 20. In the illustrated example, the volume of the second groove 25 is substantially equal to the volume of the first groove 24. Specifically, the volume of the second groove 25 is 0.9 to 1.1 times the volume of the first groove 24. This also further effectively suppresses the warping of the first retaining member 20.

[0086] Furthermore, in the illustrated example, the second groove 25 does not overlap with the first groove 24 when viewed in the axial direction of the first planar coil 11. This makes it easy to set the depths of the first groove 24 and the second groove 25 to the desired depth. In other words, it is possible to prevent the first groove 24 and the second groove 25 from communicating and forming a through hole in the first retaining member 20. Alternatively, the risk that the distance between the bottom surface of the first groove 24 and the outer surface 20S2, and / or the distance between the bottom surface of the second groove 25 and the contact surface 20S1, may be too small, causing the strength of the first retaining member 20 to fall below the desired strength, is suppressed.

[0087] Furthermore, by forming a second groove 25 on the outer surface 20S2 of the first retaining member 20, the heat dissipation performance of the coil component 10 can also be improved.

[0088] (First magnetic shielding member) The first magnetic shielding member 40 is provided to suppress magnetic transmission and / or leakage magnetic fields. The first magnetic shielding member 40 is a sheet-like member separate from the first planar coil 11, the second planar coil 12, the first retaining member 20, and the second retaining member 30. The fact that the first magnetic shielding member 40 is separate from the first planar coil 11, the second planar coil 12, the first retaining member 20, and the second retaining member 30 means that the first magnetic shielding member 40 is not integrated with these first planar coil 11, the second planar coil 12, the first retaining member 20, and the second retaining member 30. However, the first magnetic shielding member 40 and the second retaining member 30 may be joined via an adhesive layer or the like. The first magnetic shielding member 40 is formed to be sized to encompass the first planar coil 11, the second planar coil 12, and the second retaining member 30 in a plan view. The first magnetic shielding member 40 overlaps with the first planar coil 11, the second planar coil 12, and the second retaining member 30, and is in direct contact with the second retaining member 30.

[0089] In this embodiment, the first magnetic shielding member 40 is magnetic and contains or is made of a magnetic material. In the coil component 10, a magnetic field is generated when current is supplied to the first planar coil 11 and the second planar coil 12. The magnetic field generated in such a coil component 10 is generated to spread in all directions with respect to the respective central axes C1 and C2 of the first planar coil 11 and the second planar coil 12. In this case, because the first magnetic shielding member 40 is magnetic, it can orient the spreading magnetic flux lines toward the respective central axes C1 and C2. Furthermore, the coil component 10 can be installed in a vehicle, but in this case, if the magnetic field generated in the coil component 10 flows toward other vehicle parts, it may adversely affect the vehicle parts. In such cases, the first magnetic shielding member 40 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0090] The first magnetic shielding member 40 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the first magnetic shielding member 40 includes ferrite, preferably soft ferrite.

[0091] The relative permeability of the first magnetic shielding member 40 may be 500 or more, or 1000 or more. The relative permeability of the first magnetic shielding member 40 may be 500 or more and 3000 or less, or 1000 or more and 3000 or less. In this specification, the relative permeability is the value measured at a frequency of 85 kHz and an ambient temperature of 23 degrees Celsius.

[0092] (Second magnetic shielding member) The second magnetic shielding member 50 is provided so as to cover the first magnetic shielding member 40. In this embodiment, the second magnetic shielding member 50 is in contact with the first magnetic shielding member 40, but alternatively, the second magnetic shielding member 50 may be in contact with the first magnetic shielding member 40 via a spacer. The second magnetic shielding member 50 is made of a metallic material and is conductive. Specifically, in this embodiment, the second magnetic shielding member 50 is made of aluminum. In this case, leakage of magnetism from the first planar coil 11 and the second planar coil 12 through the second magnetic shielding member 50 is suppressed. The second magnetic shielding member 50 may be made of an aluminum alloy, copper, stainless steel, or the like.

[0093] (Connection terminals) As shown in Figures 2 and 3, the first connection terminal 61 is connected to the radially outer end of the turn portion 115 in the first planar coil 11. The second connection terminal 62 is connected to the radially outer end of the turn portion 125 in the second planar coil 12. The first connection terminal 61 and the second connection terminal 62 can be used, for example, when connecting to a high-frequency current supply unit 1A or a 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, and for example, a connection using a conductive adhesive may be employed.

[0094] <Manufacturing method for coil component 10> Next, an example of a method for manufacturing the coil component 10 will be described. Figure 8 is a perspective view of a mold 200 for manufacturing the coil component 10. Figure 9 is a cross-sectional view showing the first planar coil 11 and the molding material 220 (described later) placed in the mold 200 shown in Figure 8.

[0095] First, a mold 200 as shown in Figure 8 is prepared, and the first planar coil 11 is placed inside the mold 200 as shown in Figure 9. The mold 200 has irregularities corresponding to the irregularities of the contact surface 20S1 of the first holding member 20. Specifically, the mold 200 includes a plate-shaped main body portion 201 having a flat mounting surface 200S on which the first planar coil 11 is placed. The main body portion 201 has a convex portion 202 that protrudes from the mounting surface 200S and extends in a spiral shape. The convex portion 202 is the portion that forms the first groove 24 of the first holding member 20. The first planar coil 11 is then placed in a spiral-shaped region on the mounting surface 200S that extends along the spiral-shaped convex portion 202. Viewed in the axial direction of the first planar coil 11, the convex portion 202 is located between adjacent turn portions of the first planar coil 11.

[0096] Next, a material 220 for manufacturing the first holding member 20 shown in Figures 6 and 7 is prepared. In the illustrated example, the material 220 is a molded material formed into a plate shape overall. A second groove 25 is formed on one surface of the molded material 220. Then, as shown in Figure 9, the molded material 220 is placed on the mold 200 and the first planar coil 11. At this time, the molded material 220 is placed on the mold 200 and the first planar coil 11 so that the other surface of the molded material 220 (the surface opposite to the surface on which the second groove 25 is formed) faces the mold 200 and the first planar coil 11. Next, the first planar coil 11 and the molded material 220 are heat-pressed between the mold 200 and another mold 210.

[0097] The molding material 220 softens and melts upon heat pressing. This creates a groove on the other surface of the molding material 220 corresponding to the protrusion 202 of the mold 200. In this way, the first retaining member 20 having the first groove 24 is formed. Viewed in the axial direction of the first planar coil 11, the first groove 24 is formed between adjacent turns of the first planar coil 11. Furthermore, as the first retaining member 20 cools and solidifies, the first retaining member 20 and the first planar coil 11 are integrated. In this way, the coil intermediate material 10M shown in Figure 5 is manufactured.

[0098] Next, processes such as integrating the second planar coil 12 and the second holding member 30 into the coil intermediate material 10M are carried out to manufacture the coil component 10. In this embodiment, the molding material 220 is melted between the molds 200 and 210 by hot pressing to form the coil intermediate material 10M in which the first planar coil 11 and the first holding member 20 are integrated. However, this manufacturing method is just one example. For example, the coil intermediate material 10M may be formed by injecting the molding material between the molds 200 and 210. Also, when the molding material for the first holding member 20 is hot-pressed in the mold 210, the mold 210 may form a second groove 25 in the first holding member 20.

[0099] <Applications of coil components> The coil component 10 according to this embodiment can be used as a power transmission coil in the power transmission 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.

[0100] When the coil component 10 is used as a power transmission coil, the first connection terminal 61 and the second connection terminal 62 are connected to a high-frequency current supply unit 1A or an AC power source as shown in Figure 1. When a high-frequency current is supplied to the coil component 10, the current can be passed from the first connection terminal 61 to the first planar coil 11 and the second planar coil 12, and then from the second connection terminal 62 to the high-frequency current supply unit 1A or the AC power source. Alternatively, the current can be passed from the second connection terminal 62 to the second planar coil 12 and the first planar coil 11, and then from the first connection terminal 61 to the high-frequency current supply unit 1A or the AC power source. This makes it possible to generate a magnetic field including magnetic field lines along the central axis of the planar coils.

[0101] On the other hand, when the coil component 10 is used as the power receiving coil, a high-frequency current can be generated in the first planar coil 11 and the second planar coil 12 by receiving or generating a magnetic field including magnetic field lines that passes inside the first planar coil 11 and the second planar coil 12. This high-frequency current can then be supplied to an external device from the first connection terminal 61 or the second connection terminal 62.

[0102] Furthermore, the coil component 10 can also be used in transformers, antennas, and the like. For example, when the coil component 10 functions as the primary coil in a transformer, the first connection terminal 61 and the second connection terminal 62 are connected to an AC power source. By supplying a high-frequency current, magnetic flux can be supplied to the iron core from the center of the planar coil.

[0103] <Variation> It should be noted that various modifications can be made to the embodiment described above. For example, the coil component 10 includes, but is not limited to, two planar coils 11 and 12. The number of planar coils included in the coil component 10 may be one or three or more.

[0104] Furthermore, the coil component 10 includes, but is not limited to, plate-shaped planar coils 11 and 12 whose cross-sectional shape in the direction in which the planar coils 11 and 12 circulate in a spiral shape is rectangular. The planar coils 11 and 12 do not have to be plate-shaped. The coil component 10 may also include a planar coil formed from Litz wire. Litz wire is made by twisting together a plurality of conductors. In this case, the cross-sectional shape of the planar coil in the direction in which the planar coil circulates in a spiral shape may be circular.

[0105] Furthermore, in the embodiment described above, the warping of the first retaining member 20 is suppressed by forming a second groove 25 on the outer surface 20S2 of the first retaining member 20, but the invention is not limited to this. For example, as shown in Figures 10 to 12, the warping of the first retaining member 20 may be suppressed by forming at least one rib 70 on the outer surface 20S2. By forming a rib 70 on the outer surface 20S2, the rigidity of the outer surface 20S2 of the first retaining member 20 is increased, and the warping of the first retaining member 20 can be suppressed.

[0106] In the illustrated example, the rib 70 is formed in a region 20R2 on the outer surface 20S2 that overlaps with a region 20R1 on the contact surface 20S1 containing the central axis C1 of the first planar coil 11 and the first groove 24 when viewed in the axial direction (see Figures 11 and 12). This increases the rigidity of the outer surface 20S2 of the first retaining member 20 in the portion of the first retaining member 20 that is prone to warping, thereby effectively suppressing warping of the first retaining member 20.

[0107] Furthermore, in the illustrated example, the outer surface 20S2 has a plurality of ribs 70 extending in directions that intersect each other. This makes it possible to suppress warping of the first retaining member 20 in multiple directions.

[0108] Furthermore, in the illustrated example, multiple ribs 70 are formed in a grid pattern on the outer surface 20S2 when viewed in the axial direction of the first planar coil 11. This effectively suppresses warping of the first holding member 20 in multiple directions.

[0109] Furthermore, by forming ribs 70 on the outer surface 20S2 of the first retaining member 20, the heat dissipation performance of the coil component 10 can also be improved.

[0110] The coil component 10 according to the embodiment described above comprises a planar coil 11, a first retaining member 20, and a second retaining member 30. The planar coil 11 has a spiral shape and includes a first surface 11A and a second surface 11B that are opposite to each other in the axial direction extending along the central axis C1 of the spiral shape. The first retaining member 20 overlaps the planar coil 11 so as to face the second surface 11B of the planar coil 11 and holds the planar coil 11. The second retaining member 30 is integrated with the planar coil 11 and the first retaining member 20 by sandwiching the planar coil 11 between the first retaining member 20. The planar coil 11 includes a plurality of turn portions 11n arranged in the radial direction of the planar coil 11. The second retaining member 30 has a projection 32 that extends along the axial direction between adjacent turn portions of the planar coil 11. The first retaining member 20 has a contact surface 20S1 that contacts the second surface 11B, and an outer surface 20S2 opposite to the contact surface 20S1. A first groove 24 for receiving the protrusion 32 is formed on the contact surface 20S1. A second groove 25 is formed on the outer surface 20S2. The second groove 25 is formed in a region 20R2 on the outer surface 20S2 that overlaps with a region 20R1 on the contact surface 20S1 that includes the central axis C1 and the first groove 24 when viewed in the axial direction. With such a coil component 10, the difference between the degree of contraction of the first retaining member 20 in each region on the contact surface 20S1 and the degree of contraction of the first retaining member 20 in each region on the outer surface 20S2 corresponding to each region can be reduced, and the warping of the first retaining member 20 can be effectively suppressed.

[0111] Furthermore, in the embodiment described above, the second groove 25 is formed along the spiral shape of the planar coil 11 when viewed in the axial direction. This effectively reduces the difference between the degree of contraction of the first retaining member 20 in each region on the contact surface 20S1 and the degree of contraction of the first retaining member 20 in each region on the outer surface 20S2 corresponding to each region.

[0112] Furthermore, in the embodiment described above, the width of the second groove 25 is 0.2 to 1.1 times the width of the first groove 24. This effectively suppresses warping of the first retaining member 20.

[0113] Furthermore, in the embodiment described above, the depth of the second groove 25 is 0.2 to 1.1 times the depth of the first groove 24. This effectively suppresses warping of the first retaining member 20.

[0114] Furthermore, in the embodiment described above, the total volume of the second groove 25 is 0.2 to 1.1 times the total volume of the first groove 24. This effectively suppresses warping of the first retaining member 20.

[0115] Furthermore, in the embodiment described above, the second groove 25 does not overlap with the first groove 24 when viewed in the axial direction. This makes it easy to set the depths of the first groove 24 and the second groove 25 to a desired depth.

[0116] Furthermore, the coil component 10 according to the modified example described above comprises a planar coil 11, a first retaining member 20, and a second retaining member 30. The planar coil 11 has a spiral shape and includes a first surface 11A and a second surface 11B that are opposite to each other in the axial direction extending along the central axis C1 of the spiral shape. The first retaining member 20 overlaps the planar coil 11 so as to face the second surface 11B and holds the planar coil 11. The second retaining member 30 is integrated with the planar coil 11 and the first retaining member 20 by sandwiching the planar coil 11 between the first retaining member 20. The planar coil 11 includes a plurality of turn portions 11n arranged in the radial direction of the planar coil 11. The second retaining member 30 has projections 32 that extend along the axial direction between adjacent turn portions of the planar coil 11. The first retaining member 20 has a contact surface 20S1 that contacts the second surface 11B, and an outer surface 20S2 opposite to the contact surface 20S1. A first groove 24 for receiving the projection 32 is formed in the contact surface 20S1. At least one rib 70 is formed on the outer surface 20S2. The at least one rib 70 is formed in a region 20R2 on the outer surface 20S2 that overlaps with a region 20R1 on the contact surface 20S1 that includes the central axis C1 and the first groove 24 when viewed in the axial direction. With such a coil component 10, the rigidity of the outer surface 20S2 of the first retaining member 20 can be increased in the part of the first retaining member 20 that is prone to warping, and warping of the first retaining member 20 can be effectively suppressed.

[0117] Furthermore, in the modified examples described above, at least one rib 70 includes a plurality of ribs 70 extending in directions that intersect each other. This makes it possible to suppress warping of the first retaining member 20 in multiple directions.

[0118] Furthermore, in the modified examples described above, at least one rib 70 includes multiple ribs 70, and the multiple ribs 70 are formed in a grid pattern when viewed in the axial direction. This effectively suppresses warping of the first retaining member 20 in multiple directions.

[0119] Furthermore, in the embodiment and modified examples described above, the first retaining member 20 is non-magnetic and insulating.

[0120] Furthermore, in the embodiment and modified examples described above, the second holding member 30 is magnetic.

[0121] Furthermore, in the embodiment and modified examples described above, the planar coil 11 is formed in a plate shape.

[0122] Furthermore, in the modified examples described above, the planar coil 11 is formed using Litz wire.

[0123] The coil intermediate material 10M according to one embodiment described above comprises a planar coil 11 and a first holding member 20. The planar coil 11 has a spiral shape and includes a first surface 11A and a second surface 11B that are opposite to each other in the axial direction extending along the central axis C1 of the spiral shape. The first holding member 20 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 to the contact surface 20S1. A first groove 24 is formed on the contact surface 20S1. A second groove 25 is formed on the outer surface 20S2. The first groove 24 is formed along the spiral shape of the planar coil 11, between adjacent turn portions of the planar coil 11, when viewed in the axial direction. The second groove 25 is formed in region 20R2 on the outer surface 20S2, which overlaps with region 20R1 on the contact surface 20S1 containing the central axis C1 and the first groove 24, when viewed in the axial direction. With such a coil intermediate material 10M, the difference between the degree of contraction of the first retaining member 20 in each region on the contact surface 20S1 and the degree of contraction of the first retaining member 20 in each region on the outer surface 20S2 corresponding to each region can be reduced, and the warping of the first retaining member 20 can be effectively suppressed.

[0124] Furthermore, in the modified examples described above, the second groove 25 is formed along the spiral shape of the planar coil 11 when viewed in the axial direction. This effectively reduces the difference between the degree of contraction of the first retaining member 20 in each region on the contact surface 20S1 and the degree of contraction of the first retaining member 20 in each region on the outer surface 20S2 corresponding to each region.

[0125] The coil intermediate material 10M according to the modified form described above comprises a planar coil 11 and a first retaining member 20. The planar coil 11 has a spiral shape and includes a first surface 11A and a second surface 11B that are opposite to each other in the axial direction extending along the central axis C1 of the spiral shape. The first retaining member 20 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. The first retaining member 20 has a contact surface 20S1 that contacts the second surface 11B and an outer surface 20S2 opposite to the contact surface 20S1. A first groove 24 is formed on the contact surface 20S1. At least one rib 70 is formed on the outer surface 20S2. The first groove 24 is formed along the spiral shape of the planar coil 11 between adjacent turn portions of the planar coil 11 when viewed in the axial direction. At least one rib 70 is formed in a region 20R2 on the outer surface 20S2 that overlaps with a region 20R1 on the contact surface 20S1 containing the central axis C1 and the first groove 24 when viewed in the axial direction. With such a coil intermediate material 10M, the rigidity of the outer surface 20S2 of the first retaining member 20 can be increased in the portion of the first retaining member 20 that is prone to warping, and warping of the first retaining member 20 can be effectively suppressed.

[0126] Furthermore, in the modified examples described above, at least one rib 70 includes a plurality of ribs 70 extending in directions that intersect each other. This makes it possible to suppress warping of the first retaining member 20 in multiple directions.

[0127] The power transmission device 1 and / or power receiving device 2 according to the embodiment and / or modification thereof described above are equipped with the coil component 10 described above.

[0128] The power transmission system S according to one embodiment and its modifications described above comprises a power transmission device 1 and a power receiving device 2. At least one of the power transmission device 1 and the power receiving device 2 is equipped with the coil component 10 described above.

[0129] In addition, while several modifications of the above-described embodiments have been explained, it is naturally possible to combine and apply multiple modifications as appropriate. [Explanation of symbols]

[0130] S...Power transmission system 1... Power transmission equipment 1A…High-frequency current supply unit 2…Power receiving device 2A...Conversion section 10…Coil components 10M…Coil intermediate material 11…First Planar Coil 11A...First face 11B...Second side 11n... Turn section 11E... Conductor 12…Second Planar Coil 12A...First face 12B...Second side 12n... Turn section 12E...Conductor 20…First retaining member 24... The first trench 25…The second groove 30...Second retaining member 31...Base 32...Protruding part 40…First magnetic shielding member 50…Second magnetic shielding member 61...First connection terminal 62...Second connection terminal 70... Rib 200… Mold 200S…Installation surface 201…Body part 202...Convex part 210...Other molds 220…forming material C1…First Central Axis C2…Second Central Axis

Claims

1. A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, A first holding member overlaps with the planar coil so as to face the second surface and holds the planar coil, The planar coil is sandwiched between the planar coil and the first holding member, and a second holding member is integrated with the planar coil and the first holding member, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The second holding member is magnetic and has protrusions that extend along the axial direction between adjacent turn portions of the planar coil. The first retaining member is nonmagnetic and insulating, and has a contact surface that contacts the second surface, and an outer surface opposite to the contact surface. A first groove for receiving the protrusion is formed on the contact surface. A second groove is formed on the outer surface, A coil component wherein the second groove is formed in a region on the outer surface that overlaps with the region on the contact surface including the central axis and the first groove when viewed in the axial direction.

2. The coil component according to claim 1, wherein the second groove is formed along the spiral shape of the planar coil when viewed in the axial direction.

3. The coil component according to claim 1, wherein the width of the second groove is 0.2 to 1.1 times the width of the first groove.

4. The coil component according to claim 1, wherein the depth of the second groove is 0.2 to 1.1 times the depth of the first groove.

5. The coil component according to claim 1, wherein the volume of the second groove is 0.2 to 1.1 times the volume of the first groove.

6. The coil component according to claim 2, wherein the second groove does not overlap with the first groove when viewed in the axial direction.

7. A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, A first holding member overlaps with the planar coil so as to face the second surface and holds the planar coil, The planar coil is sandwiched between the planar coil and the first holding member, and a second holding member is integrated with the planar coil and the first holding member, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The second holding member is magnetic and has protrusions that extend along the axial direction between adjacent turn portions of the planar coil. The first retaining member is nonmagnetic and insulating, and has a contact surface that contacts the second surface, and an outer surface opposite to the contact surface. A first groove for receiving the protrusion is formed on the contact surface. At least one rib is formed on the outer surface, A coil component wherein the at least one rib is formed in a region on the outer surface that overlaps with a region on the contact surface including the central axis and the first groove, when viewed in the axial direction.

8. The coil component according to claim 7, wherein the at least one rib includes a plurality of ribs extending in directions intersecting each other.

9. The aforementioned at least one rib includes a plurality of ribs, The coil component according to claim 7, wherein the plurality of ribs are formed in a grid pattern when viewed in the axial direction.

10. The coil component according to claim 1 or 7, wherein the material of the first retaining member is resin or fiber-reinforced plastic.

11. The coil component according to claim 1 or 7, wherein the planar coil is formed in the shape of a plate.

12. The coil component according to claim 1 or 7, wherein the planar coil is formed using Litz wire.

13. A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, The device comprises a first holding member that overlaps with the planar coil so as to face the second surface and holds the planar coil, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The first retaining member is nonmagnetic and insulating, and has a contact surface that contacts the second surface, and an outer surface opposite to the contact surface. A first groove is formed on the contact surface, A second groove is formed on the outer surface, The first groove is formed along the spiral shape of the planar coil between adjacent turn portions of the planar coil when viewed in the axial direction. The coil intermediate material is formed in a region on the outer surface that overlaps with the region on the contact surface including the central axis and the first groove when viewed in the axial direction.

14. The coil intermediate material according to claim 13, wherein the second groove is formed along the spiral shape of the planar coil when viewed in the axial direction.

15. A planar coil having a spiral shape, including a first surface and a second surface that are opposite to each other in the axial direction extending along the central axis of the spiral shape, The device comprises a first holding member that overlaps with the planar coil so as to face the second surface and holds the planar coil, The planar coil includes a plurality of turned portions arranged in the radial direction of the planar coil, The first retaining member is nonmagnetic and insulating, and has a contact surface that contacts the second surface, and an outer surface opposite to the contact surface. A first groove is formed on the contact surface, At least one rib is formed on the outer surface, The first groove is formed along the spiral shape of the planar coil between adjacent turn portions of the planar coil when viewed in the axial direction. A coil intermediate material wherein the at least one rib is formed in a region on the outer surface that overlaps with a region on the contact surface including the central axis and the first groove when viewed in the axial direction.

16. The coil intermediate material according to claim 15, wherein the at least one rib includes a plurality of ribs extending in directions intersecting each other.

17. The coil intermediate material according to claim 13 or 15, wherein the material of the first holding member is resin or fiber-reinforced plastic.

18. A power transmission device comprising the coil component described in claim 1 or 7.

19. A power receiving device comprising the coil component described in claim 1 or 7.

20. It comprises a power transmission device and a power receiving device, A power transmission system in which at least one of the power transmission device and the power receiving device comprises the coil component described in claim 1 or 7.

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