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

Abstract

A coil component (100) according to one embodiment comprises: a planar coil (110) that includes a plurality of turn portions (1101-1108); and a first conductive wire portion (161A) that is connected to an inner end portion of the planar coil (110) in the radial direction of the first turn portion (1101) positioned farthest inward in the radial direction, and extends outward in the radial direction so as to sequentially intersect the plurality of turn portions (1101-1108). The distance (CL8) in the axial direction between the eighth turn part (1108) positioned outermost in the radial direction and a first conductor part (161A) is larger than the distance (CL1) in the axial direction between the first conductor part (161A) and a connection part (161C) with the first conductor part (161A) in the first turn part (1101) positioned farthest inward in the radial direction.

Description

Coil component, power transmitting device, power receiving device, and power transmission system

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

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

[0003] For example, a system is known that transmits power contactlessly by passing a high-frequency current through a resonant circuit including a coil.

[0004] When a high-frequency current flows through a coil, the skin effect can occur. The skin effect increases AC resistance, causing a decrease in transmission efficiency during power transmission. Taking this into consideration, if the coil is made of litz wire, the skin effect can be suppressed, and the decrease in transmission efficiency can be suppressed. However, because litz wire is made by twisting together many enameled wires, it is expensive to manufacture and requires a lot of effort, and the larger the coil size, the greater the manufacturing effort.

[0005] On the other hand, a technique using a spiral, plate-shaped planar coil with a rectangular conductor cross section is also known (see Patent Document 1). Such a planar coil can be formed, for example, by punching it out of a plate material. Therefore, such a planar coil can improve manufacturing efficiency regardless of the size of the coil. It is also advantageous in terms of reducing the thickness and weight of the device in which the coil is incorporated.

[0006] Japanese Patent Application Laid-Open No. 2020-47614

[0007] When connecting the planar coil to, for example, a power source, connection terminals connected to the radially inner end and the radially outer end of the planar coil may be connected to the power source via wiring. In this case, for example, the connection terminal connected to the radially inner end may include a conductor portion extending from the radially inner to the radially outer side so as to intersect sequentially with the plurality of turns of the planar coil, and a terminal portion provided at the radially outer end of the conductor portion.

[0008] However, when the conductor portions extend as described above, if the distance between the crossing conductor portions and the turn portions becomes small, dielectric breakdown or short-circuiting becomes more likely to occur between them. On the other hand, in some planar coils, a ferrite sheet that functions as a magnetic shield and an aluminum plate are stacked in that order, and in such cases, it is also necessary to consider how to avoid dielectric breakdown or short-circuiting between the conductor portions and the aluminum plate.

[0009] When a ferrite sheet and an aluminum plate are stacked on a planar coil as described above, a notch or gap may be formed in a portion of the ferrite sheet, and the conductor portion may be passed through the notch or gap located between the aluminum plate and the planar coil. In this configuration, if a large distance is attempted between the conductor portion and the turn portion, dielectric breakdown or short-circuiting between the conductor portion and the aluminum plate becomes more likely. If a large distance is attempted between the aluminum plate and the planar coil to avoid this, the overall thickness increases, thereby diminishing the advantages of the planar coil. Therefore, simply increasing the distance between the conductor portion and other conductive parts is not necessarily a good solution. Furthermore, since ferrite sheets are relatively heavy, weight reduction is anticipated, and thinning can be achieved to achieve this. However, thinning the ferrite sheet also increases the risk of dielectric breakdown or short-circuiting between the planar coil and the aluminum plate, which is also a concern.

[0010] The object of the present disclosure is to provide a coil component, a power transmitting device, a power receiving device, and a power transfer system that can properly ensure insulation between a conductor portion connected to the end of a planar coil and other conductive portions such as a turn portion of the planar coil while preventing an increase in size or achieving a reduction in size, in other words, that can suppress insulation breakdown or short circuits that may occur in the coil component while preventing an increase in size or achieving a reduction in size.

[0011] The embodiments of the present disclosure relate to the following [1] to

[18] .

[0012] [1] A coil component comprising: a planar coil including a plurality of turn portions arranged in the radial direction; and a conductor portion connected to an inner end of a turn portion of the planar coil that is located innermost in the radial direction, and extending radially outward so as to sequentially intersect with the plurality of turn portions, wherein the distance in the axial direction of the planar coil between the turn portion that is located outermost in the radial direction and the conductor portion is greater than the distance in the axial direction between the conductor portion and a connection portion of the turn portion that is innermost in the radial direction and the conductor portion.

[0013] [2] The coil component according to [1], wherein the distance between the plurality of turn portions and the conductor portion increases toward the outside in the radial direction.

[0014] [3] The coil component according to [1] or [2], wherein the plurality of turn portions are positioned so as to be arranged on the same plane, and the conductor portion extends so as to be inclined with respect to the plane.

[0015] [4] The coil component according to any one of [1] to [3], further comprising a first shielding member that is overlapped with the planar coil and has magnetic and insulating properties, wherein the conductor portions extend so that the distance in the axial direction from the first shielding member increases as the conductor portions extend radially outward.

[0016] [5] The coil component according to any one of [1] to [4], wherein at least the turn portion located outermost in the radial direction among the plurality of turn portions is bent so as to move away from the conductor portion at a position where the turn portion intersects with the conductor portion.

[0017] [6] The coil component according to any one of [1] to [5], wherein all of the turn portions that intersect with the conductor portion among the plurality of turn portions are bent so as to move away from the conductor portion at positions where they intersect with the conductor portion.

[0018] [7] The coil component according to [5] or [6], further comprising a first shielding member that is overlapped with the planar coil and has magnetic and insulating properties, wherein the turn portion that is bent so as to move away from the conductor portion at a position where it intersects with the conductor portion is bent so as to move away from the first shielding member.

[0019] [8] The coil component according to any one of [1] to [7], wherein the turn portion located most inward in the radial direction and the conductor portion are connected via a conductive connecting portion, and the distance in the axial direction between the turn portion located most outward in the radial direction and the conductor portion is greater than a thickness of the conductive connecting portion.

[0020] [9] The coil component according to any one of [1] to [8], further comprising a first shield member that is overlapped with the planar coil and has magnetic and insulating properties.

[0021]

[10] The coil component according to [9], wherein the conductor portion is arranged on a side of the planar coil opposite to a side of the first shield member.

[0022]

[11] The coil component according to

[10] , wherein the conductor portion is disposed between the planar coil and the first shield member.

[0023]

[12] The coil component according to

[11] , wherein the conductor portion is in contact with a surface of the first shield member that faces the planar coil.

[0024]

[13] The coil component according to any one of [9] to

[12] , wherein the first shielding member includes ferrite.

[0025]

[14] The coil component according to any one of [9] to

[13] , further comprising a second shielding member that is nonmagnetic and conductive and is superimposed on the first shielding member so as to face a surface of the first shielding member opposite to a surface facing the planar coil.

[0026]

[15] The coil component according to

[14] , wherein the second shielding member contains aluminum or an aluminum alloy.

[0027]

[16] A power transmission device including the coil component according to any one of [1] to

[15] .

[0028]

[17] A power receiving device including the coil component according to any one of [1] to

[15] .

[0029]

[18] A power transfer system including a power transmitting device and a power receiving device, 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

[15] .

[0030] According to the present disclosure, it is possible to suppress dielectric breakdown or short circuit that may occur in a coil component while suppressing an increase in size or while achieving miniaturization.

[0031] 8 is a diagram schematically illustrating a wireless power transmission system to which a coil component according to a first embodiment is applied. FIG. 9 is a perspective view of a coil component according to the first embodiment. FIG. 10 is an exploded perspective view of the coil component shown in FIG. 2. FIG. 11 is a plan view of the coil component shown in FIG. 2. FIG. 12 is a cross-sectional view of the coil component shown in FIG. 2 taken along line V-V in FIG. 4. FIG. 13 is a perspective view of a coil component according to a second embodiment. FIG. 14 is an enlarged perspective view of a portion of the coil component shown in FIG. 6. FIG. 15 is a plan view of the coil component shown in FIG. 6. FIG. 16 is a cross-sectional view of the coil component taken along line IX-IX in FIG. 8. FIG. 17 is a cross-sectional view of the coil component taken along line X-X in FIG. 8. FIG. 18 is a graph showing a simulation result of electric field intensity when a current is supplied to the coil component according to the first embodiment. FIG. 19 is a graph showing a simulation result of electric field intensity when a current is supplied to the coil component according to the second embodiment.

[0032] Each embodiment will be described below with reference to the drawings.

[0033] 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.

[0034] <<First Embodiment>> Fig. 1 schematically shows a wireless power transmission system S to which a coil component 100 according to a first 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 coil components according to embodiments different from the first embodiment can be applied to the power transmission system S.

[0035] <Wireless Power Transmission System> The power transmission system S includes a power transmission device 1 and a power receiving device 2. The power transmission device 1 includes a coil component 100 and a high-frequency current supply unit 1A. The coil component 100 in the power transmission device 1 functions as a power transmission coil. The high-frequency current supply unit 1A supplies a high-frequency current to the coil component 100 serving as a power transmission coil.

[0036] The power receiving device 2 includes a coil component 100 and a conversion unit 2A. The coil component 100 in the power receiving device 2 functions as a power receiving coil. The conversion unit 2A shapes the high-frequency current generated in the coil component 100. The conversion unit 2A includes a rectifier circuit that converts the high-frequency current into a direct current. The conversion unit 2A may be configured to include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0037] In the present embodiment, each of the power transmitting device 1 and the power receiving device 2 includes the coil component 100. However, the coil component 100 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.

[0038] 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 100 serving as a power transmitting coil. At this time, a magnetic field is generated in the coil component 100 by electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil component 100 serving as a power receiving coil 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 in the power transmitting device 1, 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).

[0039] The power transmission system S shown in Fig. 1 employs a magnetic field resonance method as a power transmission method. However, the coil component 100 according to the present 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.

[0040] 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 an aircraft such as a drone or a robot. The power transmission system S may also be used to transmit power to a submersible or an exploration robot in the sea. The use of the coil component 100 is not limited to wireless power transmission systems. For example, the coil component 100 may be used in a transformer, a DC-DC converter, an antenna, or the like.

[0041] <Coil Component> Fig. 2 is a perspective view of the coil component 100 according to this embodiment. Fig. 3 is an exploded perspective view of the coil component 100. Fig. 4 is a plan view of the coil component 100. Fig. 5 is a cross-sectional view of the coil component 100 taken along line VV in Fig. 2. A spacer member 120, which will be described later, is not shown in Fig. 4.

[0042] As shown in FIGS. 2 to 5 , the coil device 100 includes a planar coil 110 , a spacer member 120 , a first shield member 130 , a second shield member 150 , a first connection terminal 161 , and a second connection terminal 162 .

[0043] 5, the planar coil 110 has a first main surface 110a and a second main surface 110b. The second main surface 110b is the surface opposite to the first main surface 110a. The planar coil 110 and the spacer member 120 are integrated. The second shield member 150, the first shield member 130, the planar coil 110, and the spacer member 120 are arranged in this order in a direction from the second main surface 110b toward the first main surface 110a.

[0044] (Planar Coil) As shown in Figures 2 to 4, the planar coil 110 is formed in a spiral shape. Specifically, the planar coil 110 includes a conductor 110E formed in a spiral shape around an arbitrary central axis C. The spiral shape refers to the shape of a plane curve that moves away from the center as it turns (or moves closer to the center as it turns). The plane curve referred to here also includes a plane pattern that is bent like a broken line. In the illustrated embodiment, the spiral shape is located on an imaginary plane that is perpendicular to the central axis C.

[0045] Hereinafter, the axial direction refers to a direction extending on the central axis C or a direction parallel to the central axis C. The radial direction refers to the radial direction of a circle drawn on a plane centered at an arbitrary point on the central axis C and perpendicular to the central axis C. The circumferential direction refers to the direction along a circle centered on the central axis C (the circumferential direction of the circle).

[0046] The conductor 110E is formed from a conductive material. In this embodiment, the conductor 110E is formed from copper, but is not limited to this. The conductor 110E may be formed from a copper alloy, aluminum, an aluminum alloy, or the like. In this embodiment, the planar coil 110 is composed only of the conductor 110E. Therefore, although the planar coil 110 is formed from copper, it may also be formed from a copper alloy, aluminum, an aluminum alloy, or the like.

[0047] The planar coil 110 (conductor 110E) is plate-shaped. Specifically, the planar coil 110 is a planar coil made of non-litz wire. As shown in Fig. 5, the cross section of the conductor in a direction perpendicular to the winding direction of the spiral shape of the planar coil 110 (conductor 110E) is rectangular.

[0048] The planar coil 110 includes a plurality of turn portions 110n arranged in a direction perpendicular to the central axis C of the spiral shape. The conductor 110E is composed of the plurality of turn portions 110n. The plurality of turn portions 110n are connected so as to gradually move away from the central axis C radially outward from the central axis C. As a result, the plurality of turn portions 110n form a spiral shape as a whole.

[0049] Specifically, the turn portions 110n are basically linear conductor portions that do not form a loop but wrap around the central axis C 360 degrees. In the case of a so-called planar coil, both ends of the turn portions 110n are offset radially. In the case of multiple turn portions 110n, the radially outer end of one turn portion 110n is connected to the radially inner end of another turn portion 110n. This causes the multiple turn portions 110n to extend as a whole away from the central axis C. "Radially inward" means a direction that approaches the central axis C in the radial direction. Furthermore, "radially outward" means a direction that moves away from the central axis C in the radial direction.

[0050] In this embodiment, the turn portion 110n winds around to form a polygon. Note that the term "spiral shape" as used herein and in this disclosure refers to a planar curved shape wound in a spiral shape. The planar curved shape referred to here also includes a planar pattern that winds around repeatedly while bending like a broken line, as shown in the figure. In other words, the spiral shape refers to a planar curved shape that moves away from the center as it turns (or moves closer to the center as it turns).

[0051] In the illustrated example, the planar coil 110 (conductor 110E) includes first to eighth turn portions 1101 to 1108. The first to eighth turn portions 1101 to 1108 are arranged in this order from the innermost position in the radial direction toward the outermost position. In other words, the first turn portion 1101 is located at the innermost position in the radial direction, and the eighth turn portion 1108 is located at the outermost position in the radial direction. In further words, the first turn portion 1101 forms the innermost portion of the planar coil 110 (conductor 110E). The eighth turn portion 1108 forms the outermost portion of the planar coil 110 (conductor 110E). In the following, when describing matters common to each of the multiple turn portions 110n, they will be referred to as the turn portion 110n or the turn portions 1101 to 1108.

[0052] Each of the turn portions 1101 to 1108 extends on the above-mentioned imaginary plane. The first to eighth turn portions 1101 to 1108 are connected in this order, thereby forming a spiral shape for the planar coil 110 (the conductor 110E). In the illustrated example, the conductor 110E has an octagonal shape as a whole. The conductor 110E is wound so that each of the turn portions 1101 to 1108 forms a roughly octagonal shape. However, the shape of the conductor 110E is not limited thereto. The conductor 110E may have a polygonal shape other than an octagonal shape (e.g., a square, a hexagon, or a dodecagon) as a whole. In this case, the turn portions 1101 to 1108 may be wound so as to roughly form a polygonal shape other than an octagon (e.g., a square, a hexagon, or a dodecagon). The conductor 110E may also have a circular shape as a whole. In this case, each of the turn portions 1101 to 1108 may be wound to form a substantially circular shape.

[0053] One end of each of the turn portions 1101 to 1108 is located radially inward from the other end of the turn portion 1101 to 1108. In other words, the other end of each of the turn portions 1101 to 1108 is located radially outward from the one end of the turn portion 1101 to 1108.

[0054] As shown in FIG. 4 , each of the turn portions 1101-1108 includes a plurality of straight portions 111-119 arranged around the central axis C. Adjacent straight portions 111-119 in the circumferential direction of a circle centered on the central axis C are connected to each other. In the illustrated example, the first to seventh turn portions 1101-1107 include the first to ninth straight portions 111-119. In contrast, the eighth turn portion 1108 includes the first to eighth straight portions 111-118 but does not include the ninth straight portion 119. In the first to seventh turn portions 1101-1107, the first to ninth straight portions 111-119 are arranged in this order along the circumferential direction. In the eighth turn portion 1108, the first to eighth straight portions 111-118 are arranged in this order along the circumferential direction.

[0055] The end of the first straight portion 111 that is not connected to the second straight portion 112 forms the radially inner end of each of the turn portions 1101-1108. In the first to seventh turn portions 1101-1107, the end of the ninth straight portion 119 that is not connected to the eighth straight portion 118 forms the radially outer end of each of the first to seventh turn portions 1101-1107. The ninth straight portion 119 extends radially outward from and parallel to the first straight portion 111. In the eighth turn portion 1108, the end of the eighth straight portion 118 that is not connected to the seventh straight portion 117 forms the radially outer end. The radially inner starting points (ends of the first straight portion 111) of each of the turn portions 1101-1108 are aligned on a straight line ST (a two-dot chain line) that is parallel to a straight line extending parallel to the radial direction. The first to seventh turn portions 1101 to 1107 have their respective radially outer ends connected to the radially inner ends of the second to eighth turn portions 1108 that are adjacent to them on the radially outer side.

[0056] The planar coil 110 (conductor 110E) described above is formed by punching a metal plate such as a copper plate or an aluminum plate into a spiral shape, for example. Alternatively, the planar coil 110 can also be formed by etching a metal foil such as a copper foil or an aluminum foil into a spiral shape.

[0057] The radius of the planar coil 110 (the distance from the central axis C to the farthest point in the radial direction) may be 80 mm or more and 450 mm or less. When the coil component 100 is used as a power transmitting coil component or a power receiving coil component of a power transmission system S that transmits power to an electric vehicle by magnetic field resonance, the radius of the planar coil 110 may be 200 mm or more and 350 mm or less.

[0058] The thickness of the planar coil 110 (the conductor 110E) is measured along the axial direction of the planar coil 110. The thickness of the planar coil 110 (the thickness of the conductor 110E) may be, for example, 0.1 mm to 2.0 mm, 0.2 mm to 1.0 mm, or 0.3 mm to 0.7 mm. The thickness of the planar coil 110 (the conductor 110E) may be, for example, 0.15 mm to 0.35 mm. When transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit 1 kW or more, preferably 5 kW or more, in a high-frequency current frequency range of 10 kHz to 200 kHz, particularly 79 kHz to 90 kHz. In this case, the thickness of the planar coil 110 made of copper is preferably 0.4 mm or more.

[0059] The line width of the planar coil 110 (conductor 110E) 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 range of, for example, 79 kHz to 90 kHz, the line width of each turn portion 1101 to 1108 may be 2 mm to 20 mm, 2 mm to 16 mm, 2 mm to 12 mm, or 2 mm to 8 mm. The line width refers to the distance between the inner and outer peripheral surfaces of the linear portion of the planar coil 110 (conductor 110E) in a cross section perpendicular to the direction in which the planar coil 110 (conductor 110E) winds around.

[0060] The aspect ratio of the planar coil 110 (conductor 110E) having a rectangular cross section is determined by dividing the line width (the radial width of each turn portion 110n) of the planar coil 110 (conductor 110E) by the thickness of the planar coil 110 (conductor 110E). The aspect ratio of the planar coil 110 (conductor 110E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0061] The thickness and line width of the planar coil 110 (conductor 110E) may be measured by cutting the coil component 100 in the axial direction to expose the planar coil 110 (conductor 110E) at a cross section, by measuring each part of the planar coil 110 (conductor 110E) with a ruler or the like, or by analyzing a cross-sectional image.

[0062] In this embodiment, the central axis C is determined as follows. First, linear imaginary turn sections similar in shape to the innermost turn section 1101 are drawn sequentially from the radially inner end of the innermost turn section 1101 in a spiral shape extending radially inward. Drawing is continued until all imaginary turn sections that fit within a diameter of 1 cm are drawn. A line that passes through the radially inner region of the imaginary turn sections that fit within a diameter of 1 cm in a direction perpendicular to the circumferential and radial directions of the spiral shape is determined to be the central axis C.

[0063] (Spacer Member) The spacer member 120 is a member that fills the gap between the planar coil 110 and the first shield member 130. The spacer member 120 overlaps the planar coil 110 in the axial direction of the planar coil 110. By being integrated with the spacer member 120, the planar coil 110 is held at a position separated from the first shield member 130.

[0064] The spacer member 120 is in direct contact with the second main surface 110b of the planar coil 110. In other words, the spacer member 120 is in direct contact with the conductor 110E. In the illustrated example, the spacer member 120 is in close contact with the second main surface 110b of the planar coil 110. In other words, the spacer member 120 is in close contact with the conductor 110E. In the illustrated example, the spacer member 120 is formed so that its outer edge is located outside the planar coil 110 when viewed in the axial direction.

[0065] Furthermore, the spacer member 120 is magnetic and has the function of suppressing magnetic permeation and / or leakage magnetic fields. Specifically, the spacer member 120 is magnetic and insulating. The magnetic field generated by the coil component 100 spreads in all directions relative to the central axis C of the planar coil 110. In this case, the magnetic properties of the spacer member 120 allow the spreading magnetic flux lines to be directed toward the central axis C. Furthermore, if the magnetic field generated by the coil component 100 reaches peripheral components located around the coil component 100, adverse effects may be caused on the peripheral components. For this reason, the spacer member 120 is provided to prevent magnetic field lines from reaching the peripheral components. As a result, the spacer member 120 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0066] The spacer member 120 includes, for example, a holding material containing resin and a plurality or an infinite number of magnetic particles made of a magnetic material. The magnetic particles are held by the holding material. The holding material is insulating, more specifically, non-magnetic and insulating. The insulating property means that the volume resistivity is 10 １０ This means that the resistance is Ω·m or more.

[0067] The resin for forming the holding material of the spacer member 120 can be, for example, a thermosetting resin such as epoxy resin or polyimide. In this case, when the planar coil 110 and the spacer member 120 are integrated by heat pressing as described below, the resin of the spacer member 120 can be easily deformed to conform to the shape of the planar coil 110 during the heat curing process. Alternatively, a thermoplastic resin such as nylon, polyethylene, or polypropylene can also be used as the resin for forming the spacer member 120. In this case, too, the resin of the spacer member 120 can be easily deformed to conform to the shape of the planar coil 110. The holding material may also include or be made of, for example, fiber-reinforced plastic. For example, the holding material may include or be made of glass-fiber-reinforced polyamide.

[0068] The magnetic particles of the spacer member 120 may be made of one or more of ferrite, particularly soft magnetic ferrite, nanocrystalline magnetic material, silicon steel, soft magnetic iron, and amorphous metal.

[0069] As shown in FIG. 5 , the spacer member 120 has a spiral-shaped recess 122 that corresponds to the spiral shape of the planar coil 110. The recess 122 is a portion of the spacer member 120 that is recessed in the axial direction of the planar coil 110, in other words, in the thickness direction of the spacer member 120. The recess 122 has a spiral shape when viewed in the axial direction of the planar coil 110. At least a portion of the planar coil 110 is housed in the recess 122 with its spiral shape aligned with the spiral shape of the recess 122. More specifically, the recess 122 houses the entire conductor 110E. Therefore, as shown in FIG. 5 , the spacer member 120 is in direct contact with three surfaces of the planar coil 110 other than the first main surface 110a.

[0070] The relative magnetic permeability of the spacer member 120 is preferably 2.0 or more, and may be 2.0 or more and 20.0 or less. The relative magnetic permeability of the spacer member 120 is more preferably 5.0 or more, and may be 5.0 or more and 20.0 or less. The relative magnetic permeability of the spacer member 120 is not particularly limited, but if it is too high, the flexibility and strength of the spacer member 120 may be undesirably impaired. Therefore, the relative magnetic permeability of the spacer member 120 may be 30 or less.

[0071] In this embodiment, the spacer member 120 is magnetic, but the spacer member 120 may be non-magnetic and insulating, for example, or may be made of resin only. Also, the spacer member 120 may not be provided, and an air layer may be formed between the planar coil 110 and the first shield member 130.

[0072] (First Shielding Member) The first shielding member 130 is provided to suppress magnetic transmission and / or leakage magnetic field. The first shielding member 130 is provided between the second shielding member 150 and the planar coil 110 and the spacer member 120. The first shielding member 130 is formed in a plate shape and extends along a plane perpendicular to the axial direction of the planar coil 110. The first shielding member 130 is sized so that its outer periphery is positioned outside the spacer member 120 and the planar coil 110 when viewed in the axial direction. In the illustrated example, the first shielding member 130 has a rectangular shape when viewed in the axial direction.

[0073] The first shield member 130 includes a magnetic material. As described above, the magnetic field generated by the coil component 100 spreads in all directions relative to the central axis C of the planar coil 110. In this case, the first shield member 130 has magnetic properties, which allows the spreading magnetic flux lines to be directed toward the central axis C. The first shield member 130 also prevents the magnetic field from reaching surrounding components. This allows the first shield member 130 to suppress leakage magnetic fields that do not contribute to the generation of current.

[0074] The first shield member 130 preferably includes a soft magnetic material. More specifically, the first shield member 130 includes ferrite, preferably soft ferrite. Alternatively, the first shield member 130 may include a nanocrystalline magnetic material.

[0075] The relative magnetic permeability of the first shield member 130 is not particularly limited, but is preferably 100 or greater, and may be 100 or greater and 10,000 or less. The relative magnetic permeability of the first shield member 130 may be 1,000 or greater, 2,000 or greater, or 3,000 or greater. The relative magnetic permeability of the first shield member 130 may be 8,000 or less, 6,000 or less, or 4,000 or less.

[0076] In the example shown in FIG. 5 , the first shield member 130 is in contact with the spacer member 120, but this is not limiting. The first shield member 130 may be spaced apart from the spacer member 120. When the first shield member 130 is positioned spaced apart from the spacer member 120, the distance between the first shield member 130 and the spacer member 120 is not particularly limited, but is, for example, 3 mm or less. Note that the longer the distance between the first shield member 130 and the spacer member 120, the more difficult it is for heat to be dissipated from the coil component 100, which may result in the coil component 100 becoming too hot. For this reason, it is preferable that the distance between the first shield member 130 and the spacer member 120 be 1 mm or less. Furthermore, reducing the distance between the first shield member 130 and the spacer member 120 is advantageous in terms of reducing the dimensions of the coil component 100 (particularly the dimensions along the axial direction).

[0077] The thickness of the first shield member 130 is not particularly limited, and may be 3 mm or less, 2 mm or less, or 1.5 mm or less. Reducing the thickness of the first shield member 130 is advantageous from the viewpoint of reducing the dimensions of the coil device 100 (particularly the dimensions along the axial direction) and miniaturization.

[0078] 3 and 4, the first shield member 130 in this embodiment is divided into multiple shield pieces 13P. In other words, the first shield member 130 includes multiple shield pieces 13P arranged in the same plane. By forming the first shield member 130 from multiple shield pieces 13P, it is possible to easily manufacture a first shield member 130 of a size such that its outer edge is located outside the planar coil 110 when viewed in the axial direction.

[0079] In the illustrated example, the first shield member 130 includes eight shield pieces 13P each having a right-angled triangular shape and approximately the same size. The eight shield pieces 13P may be referred to hereinafter as first to eighth shield pieces 131 to 138. In the illustrated example, each shield piece 13P includes soft ferrite. More specifically, each shield piece 13P is formed from a ferrite plate including soft ferrite.

[0080] In the illustrated example, each shield piece 13P is arranged adjacent to two other shield pieces 13P different from itself. Specifically, each shield piece 13P forms a quadrangle by aligning its hypotenuse with the hypotenuse of another shield piece 13P, and forms a triangle by aligning one of its two adjacent sides with another adjacent side of another shield piece 13P. Specifically, for example, the first shield piece 131 and the second shield piece 132 are adjacent to each other with their hypotenuses facing each other, and the first shield piece 131 and the eighth shield piece 138 are adjacent to each other with their adjacent sides facing each other. As a result, the first shield member 130 is formed into a quadrangle.

[0081] In the illustrated example, each of the shield pieces 131 to 138 is arranged adjacent to two different shield pieces. Gaps are formed between adjacent shield pieces 131, 132; 132, 133; 133, 134; 134, 135; 135, 136; 136, 137; 137, 138; and 138, 131. To prevent magnetic field lines from passing through the gaps, the width of the gaps is preferably 6 mm or less. In the illustrated example, the multiple shield pieces 13P are arranged so that the gaps extend radially from the central axis C, and the gaps extend perpendicular to the linear portions 111 to 119 of the turn portions 1101 to 1108. When the gaps and the straight portions 111 to 119 intersect at right angles, the magnetic field lines formed around the straight portions 111 to 119 are prevented from leaking out through the gaps, and a decrease in loss can be suppressed.

[0082] The shape and arrangement of the shield pieces 13P are not particularly limited and may differ from those shown in the example, but the dimensions of the gaps between adjacent shield pieces 13P and the state of intersection with the turn portions described above are also useful for embodiments in which the shape and arrangement of the shield pieces 13P differ from those shown in the example.

[0083] (Second Shielding Member) The second shielding member 150 is superimposed on the planar coil 110 with the first shielding member 130 interposed therebetween. In other words, the second shielding member 150 is superimposed on the first shielding member 130 so as to face the surface of the first shielding member 130 opposite the surface facing the planar coil 110. The second shielding member 150 is formed in a plate shape and extends along a plane perpendicular to the axial direction of the planar coil 110. The second shielding member 150 is sized such that its outer periphery is positioned outside the spacer member 120 and the planar coil 110, and outside the first shielding member 130, when viewed in the axial direction. In the illustrated example, the first shielding member 130 has a rectangular shape when viewed in the axial direction.

[0084] The second shield member 150 is non-magnetic and conductive. This allows the second shield member 150 to suppress magnetic transmission and / or leakage magnetic fields. This prevents the magnetic fields or electromagnetic waves generated by the coil component 100 from affecting other electronic components, the human body, etc. The second shield member 150 can be made of a metal such as aluminum or an aluminum alloy.

[0085] As shown in Fig. 5, the second shield member 150 is disposed at a distance from the first shield member 130. In the illustrated example, a spacer block 155 is disposed between the second shield member 150 and the first shield member 130 as a gap material. This maintains a predetermined distance between the second shield member 150 and the first shield member 130. The spacer block 155 is preferably an insulating and heat-conducting material. This allows the spacer block 155 to promote heat dissipation from the coil component 100.

[0086] For example, when the coil component 100 is mounted on an automobile, the installation space is limited. For example, when the coil component 100 is used for such an application, it is preferable that the coil component 100 be thin and small. Therefore, for example, when the coil component 100 is a power receiving coil component installed in an automobile, the distance between the second shield member 150 and the first shield member 130 may be 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. On the other hand, when the coil component 100 is a power transmitting coil component installed on a road or a parking lot, the distance between the second shield member 150 and the first shield member 130 may be 10 mm or more, 15 mm or more, or 20 mm or more. However, the longer the distance between the second shield member 150 and the first shield member 130, the more difficult it is for heat to be dissipated from the coil component 100, which may result in the coil component 100 becoming hot. Furthermore, even when the coil component 100 is used as a power transmitting coil component installed on a road or a parking lot, it is desirable to suppress overhang. Therefore, even when the coil component 100 is used as a power transmission coil component installed on a road or in a parking lot, the distance between the second shield member 150 and the first shield member 130 may be 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less.

[0087] On the other hand, if the second shield member 150 is disposed close to the first shield member 130, it is thought that the magnetic field lines generated by the planar coil 110 are more likely to reach the second shield member 150, which makes it easier for eddy currents to be generated in the second shield member 150. In contrast, in the present embodiment, the first shield member 130 suppresses the transmission of the magnetic field lines, thereby preventing the magnetic field lines from the planar coil 110 from reaching the second shield member 150 and suppressing dielectric breakdown or short circuiting between the planar coil 110 and the second shield member 150. This makes it easier to place the second shield member 150 close to the first shield member 130, facilitating a reduction in size and thickness.

[0088] 2 and 3 , the first connection terminal 161 is connected to the radially inner end of the first turn portion 1101 located on the innermost side of the planar coil 110. The second connection terminal 162 is connected to the radially outer end of the eighth turn portion 1108 located on the outermost side of the planar coil 110. The first connection terminal 161 and the second connection terminal 162 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A.

[0089] When the coil component 100 is used as a power transmission coil, the first connection terminal 161 and the second connection terminal 162 are connected to the high-frequency current supply unit 1A or AC power supply as shown in Fig. 1. When a high-frequency current is supplied to the coil component 100, the current can flow from the first connection terminal 161 to the planar coil 110, and then from the second connection terminal 162 to the high-frequency current supply unit 1A or AC power supply. Furthermore, the current can flow from the second connection terminal 162 to the planar coil 110, and then from the first connection terminal 161 to the high-frequency current supply unit 1A or AC power supply. This allows a magnetic field including magnetic field lines along the central axis of the planar coil 110 to be generated.

[0090] On the other hand, when the coil component 100 is used as a receiving coil, a high-frequency current can be generated in the planar coil 110 by receiving a magnetic field including magnetic field lines along the central axis of the planar coil 110. Then, this high-frequency current can be supplied to an external device from the first connection terminal 161 or the second connection terminal 162.

[0091] The first connection terminal 161 includes a first conductor portion 161A having one end connected to the radially inner end of the first turn portion 1101, and a first terminal portion 161B provided at the other end of the first conductor portion 161A. The first conductor portion 161A extends radially outward from the radially inner end of the first turn portion 1101 (the end of the first straight portion 111) so as to intersect with the plurality of turn portions 1101 to 1108 in sequence. The first conductor portion 161A extends outward beyond the outer edge of the spacer member 120, and the first terminal portion 161B is provided at a portion of the first conductor portion 161A that is positioned outward beyond the outer edge of the spacer member 120.

[0092] The second connection terminal 162 includes a second conductor portion 162A having one end connected to the radially outer end of the eighth turn portion 1108, and a second terminal portion 162B provided at the other end of the second conductor portion 162A. The second conductor portion 162A extends outward from the radially outer end of the eighth turn portion 1108 (the end of the eighth straight portion 118) beyond the outer edge of the spacer member 120. The second terminal portion 162B is provided at a portion of the second conductor portion 162A that is located outward from the outer edge of the spacer member 120.

[0093] Needless to say, the first connection terminal 161 and the second connection terminal 162 are formed from a conductive material. In this embodiment, the first connection terminal 161 and the second connection terminal 162 are formed from copper, which is the same material as the conductor 110E of the planar coil 110, but this is not limited thereto. The first connection terminal 161 and the second connection terminal 162 may also be formed from a copper alloy, aluminum, an aluminum alloy, or the like. The first connection terminal 161 and the planar coil 110 are connected by ultrasonic bonding. However, the connection method is not limited thereto, and for example, a conductive adhesive may be used for connection.

[0094] (Positional Relationship Between First Connection Terminal and Turn Portions) The positional relationship between the first connection terminal 161 and the turn portions 1101 to 1108 will be described in detail below. As shown in Figures 2 to 5, in this embodiment, the first conductor portion 161A of the first connection terminal 161 extends radially outward on the side of the planar coil 110 opposite to the side on which the first shield member 130 and the second shield member 150 are located relative to the planar coil 110 in the axial direction of the planar coil 110 so as to intersect with the plurality of turn portions 1101 to 1108 in sequence. The first conductor portion 161A is connected to a surface of the radially inner end of the first turn portion 1101 opposite to the surface facing the first shield member 130.

[0095] 5, the axial distance CL8 between the eighth turn portion 1108, which is the radially outermost of the multiple turn portions 1101-1108, and the first conductor portion 161A is greater than the axial distance CL1 between the first conductor portion 161A and the connection portion 161C of the first turn portion 1101, which is the radially innermost first turn portion 1101. In the illustrated example, the end of the first turn portion 1101 opposite the end connected to the second turn portion 1102 is connected to the first conductor portion 161A via the conductive connecting portion 170. In this embodiment, the thickness of the conductive connecting portion 170 corresponds to the dimension of the distance CL1. Therefore, the distance CL8 is greater than the thickness of the conductive connecting portion 170. More specifically, the distance CL8 is determined by the dimension between the radial center position of the part where the eighth turn portion 1108 intersects with the first conductor portion 161A and the position of the first conductor portion 161A that faces this position in the axial direction.

[0096] In this embodiment, as shown in Fig. 5, the plurality of turn portions 1101 to 1108 are positioned so as to be arranged on the same plane. On the other hand, the first conductor portion 161A extends at an angle relative to the plane, and more specifically, extends at an angle so as to move away from the planar coil 110 as it moves radially outward. More specifically, the first conductor portion 161A extends such that the axial distance from the planar coil 110, the first shield member 130, and the second shield member 150 increases as it moves radially outward. As a result, the distance between the plurality of turn portions 1101 to 1108 and the first conductor portion 161A increases as it moves radially outward.

[0097] When a current is supplied to the planar coil 110, the potential difference between the radially inner end and the radially outer end increases. Therefore, the potential difference between the first conductor portion 161A connected to the first turn portion 1101, which is located radially innermost of the planar coil 110, and the eighth turn portion 1108, which is located radially outermost, increases. In this case, if the distance between the first conductor portion 161A and the eighth turn portion 1108 is short, the electric field strength becomes excessively large, which may increase the risk of dielectric breakdown or short circuit between the first conductor portion 161A and the eighth turn portion 1108.

[0098] Therefore, in this embodiment, the axial distance CL8 between the eighth turn portion 1108 and the first conductor portion 161A is made larger than the distance CL1 between the first conductor portion 161A and the connection portion 161C of the first turn portion 1101 with the first conductor portion 161A. This reduces the electric field strength between the eighth turn portion 1108 and the first conductor portion 161A, thereby preventing dielectric breakdown or short-circuiting. In other words, increasing the volume resistance between the eighth turn portion 1108 and the first conductor portion 161A prevents dielectric breakdown or short-circuiting between the eighth turn portion 1108 and the first conductor portion 161A.

[0099] Although the size of the distance CL8 is not particularly limited, making it excessively large is undesirable from the viewpoint of miniaturization because the first connection terminal 161 will occupy only a partial area but will protrude in the axial direction. Therefore, the size of the distance CL8 may be, for example, 10 mm or less, 5 mm or less, or 3 m or less.

[0100] In the present embodiment, the first conductor portion 161A is inclined as described above, but the first conductor portion 161A may be formed, for example, in a stepped shape in which the distance from the planar coil 110 increases stepwise as it extends radially outward. Alternatively, the first conductor portion 161A may extend parallel to the radial direction from the innermost turn portion in the radial direction (first turn portion 1101) to a position between the innermost turn portion and the outermost turn portion (eighth turn portion 1108), and then incline or bend so that the distance from the planar coil 110 increases.

[0101] Furthermore, in this embodiment, a gap is formed between the first conductor portion 161A and the plurality of turn portions 1101-1108, but an insert material may be provided to maintain the distance. Such an insert material is preferably nonmagnetic and insulating. Furthermore, in this embodiment, the first turn portion 1101 is connected to the first conductor portion 161A via the conductive connecting portion 170. However, the conductive connecting portion 170 may not be provided, and the first turn portion 1101 may be connected directly to the first conductor portion 161A. In this case, the distance CL8 is preferably greater than the axial distance between the first conductor portion 161A and the turn portion (which may be the first turn portion or the second turn portion) that the first conductor portion 161A connected to the first turn portion 1101 first intersects with as it extends radially outward from the connection position with the first turn portion 1101.

[0102] The coil component 100 according to the present embodiment described above includes a planar coil 110 including a plurality of turn portions 1101 to 1108, and a first conductor portion 161A connected to a radially inner end of first turn portion 1101, which is located radially innermost in the planar coil 110, and extending radially outward so as to sequentially intersect with the plurality of turn portions 1101 to 1108. Axial distance CL8 between the radially outermost eighth turn portion 1108 and first conductor portion 161A is greater than axial distance CL1 between the first conductor portion 161A and a connection portion 161C of the radially innermost first turn portion 1101 with first conductor portion 161A.

[0103] As a result, according to this embodiment, it is possible to suppress dielectric breakdown or short-circuiting that may occur in the coil device 100 while suppressing an increase in size or achieving miniaturization. That is, when a current is supplied to the planar coil 110, a large potential difference occurs between the first conductor portion 161A connected to the first turn portion 1101, which is located radially innermost in the planar coil 110, and the eighth turn portion 1108, which is located radially outermost. If the distance between the first conductor portion 161A and the eighth turn portion 1108 is short, dielectric breakdown or short-circuiting may be more likely to occur. In contrast, in this embodiment, the axial distance CL8 between the eighth turn portion 1108 and the first conductor portion 161A is set to be greater than the distance CL1 between the first conductor portion 161A and the connection portion 161C of the first turn portion 1101 with the first conductor portion 161A. This reduces the electric field strength between the eighth turn portion 1108 and the first conductor portion 161A. As a result, it is possible to suppress the occurrence of dielectric breakdown or short circuit between the eighth turn portion 1108 and the first conductor portion 161A.

[0104] In this embodiment, the distance between first conductor portion 161A and planar coil 110 is partially increased at least between first conductor portion 161A and eighth turn portion 1108, thereby preventing coil component 100 from becoming larger due to the addition of a configuration for preventing dielectric breakdown or short circuits. Furthermore, first conductor portion 161A is not configured to pass through a notch or gap formed in first shield member 130, but rather extends away from second shield member 150. Therefore, even if the thickness of first shield member 130 is reduced, dielectric breakdown or short circuits between first conductor portion 161A and second shield member 150 are prevented, which is advantageous for miniaturization. Therefore, dielectric breakdown or short circuits that may occur in coil component 100 can be prevented while preventing the coil component from becoming larger or achieving miniaturization.

[0105] In this embodiment, the distance between the multiple turn portions 1101 and the first conductor portion 161A increases radially outward. This improves the reliability of preventing dielectric breakdown or short circuits. The multiple turn portions 1101 to 1108 are arranged on the same plane, and the first conductor portion 161A extends at an angle relative to the plane. This improves the reliability of preventing dielectric breakdown or short circuits without complicating the shape of the first conductor portion 161A.

[0106] Furthermore, in the present embodiment, first conductor portion 161A is disposed on the side opposite to first shield member 130 with respect to planar coil 110. Therefore, first conductor portion 161A is not configured to pass through a notch or gap formed in first shield member 130, and further, the constraints imposed by the position of first conductor portion 161A on the thickness and position of first shield member 130 are alleviated. Therefore, for example, by reducing the thickness of first shield member 130 and locating second shield member 150 closer to first shield member 130, it is advantageous for miniaturization and thinning.

[0107] <<Second Embodiment>> Next, a coil component 102 according to a second embodiment will be described with reference to FIGS. 6 to 10. Components in the following embodiments that are the same as or correspond to those in the first embodiment are designated by the same reference numerals. Detailed descriptions of components that have the same configuration will be omitted. FIG. 6 is a perspective view of the coil component 102. FIG. 7 is an enlarged perspective view of a portion of the coil component 102. FIG. 8 is a plan view of the coil component 102. FIG. 9 is a cross-sectional view of the coil component 102 taken along line IX-IX in FIG. 8. FIG. 10 is a cross-sectional view of the coil component 102 taken along line X-X in FIG. 8. The spacer member 120 is not shown in FIG. 10.

[0108] In the second embodiment, the configuration of the first conductor portion 161A is different from that of the first embodiment. Specifically, the first conductor portion 161A of the first connection terminal 161 is disposed on the side of the planar coil 110 where the first shield member 130 and the second shield member 150 are located in the axial direction of the planar coil 110.

[0109] The first conductor portion 161A extends radially outward from the first turn portion 1101 so as to sequentially intersect with the plurality of turn portions 1101 to 1108. The first conductor portion 161A is connected to a surface of the radially inner end of the first turn portion 1101 that faces the first shield member 130. As shown in FIGS. 9 and 10 , the first conductor portion 161A and the radially inner end of the first turn portion 1101 are connected via a conductive connecting portion 170. However, the conductive connecting portion 170 may not be provided and the first turn portion 1101 may be directly connected to the first conductor portion 161A. The spacer member 120 has a through-hole at the installation position of the conductive connecting portion 170, and the conductive connecting portion 170 is provided in this through-hole.

[0110] In this embodiment, the first conductor portion 161A extends parallel to the radial direction. In contrast, at least the eighth turn portion 1108, which is the outermost turn portion in the radial direction among the plurality of turn portions 1101-1108, is bent away from the first conductor portion 161A at a position where it intersects with the first conductor portion 161A. As a result, the distance CL8 in the axial direction of the planar coil 110 between the eighth turn portion 1108, which is the outermost turn portion in the radial direction among the plurality of turn portions 1101-1108, and the first conductor portion 161A is greater than the distance CL1 in the axial direction between the first conductor portion 161A and a connection portion 161C' of the first turn portion 1101, which is the innermost turn portion in the radial direction, and the first conductor portion 161A.

[0111] 9 , in this embodiment, the first conductor portion 161A intersects with the second turn portion 1102 to the eighth turn portion 1108. The second turn portion 1102 to the eighth turn portion 1108 that intersect with the first conductor portion 161A are all bent away from the first conductor portion 161A at the positions where they intersect with the first conductor portion 161A. In this embodiment, the second turn portion 1102 to the eighth turn portion 1108 are bent away from the first conductor portion 161A, the first shield member 130, and the second shield member 150 at the positions where they intersect with the first conductor portion 161A.

[0112] In the illustrated example, the distances between the second to seventh turn portions 1102 to 1107 and the first conductor portion 161A are each the same (substantially the same) as the distance CL8 between the eighth turn portion 1108 and the first conductor portion 161A. However, the distances between the second to eighth turn portions 1102 to 1108 and the first conductor portion 161A do not have to be the same. For example, the second to eighth turn portions 1102 to 1108 may be bent so that the distances between the second to eighth turn portions 1102 to 1108 and the first conductor portion 161A increase radially outward.

[0113] In the illustrated example, the first conductor portion 161A crosses an area including or near the connection positions of adjacent turn portions (1101, 1102; 1102, 1103; 1103, 1104; 1104, 1105; 1105, 1106; 1106, 1107; 1107, 1108). Therefore, a portion including the radially outer end of the radially inner turn portion of the adjacent turn portion is bent away from the first conductor portion 161A, and a portion including the radially inner end of the radially outer turn portion of the adjacent turn portion is bent away from the first conductor portion 161A.

[0114] 10 , the first conductor portion 161A is disposed between the planar coil 110 and the first shield member 130. Specifically, the first conductor portion 161A is disposed between the surface of the planar coil 110 facing the first shield member 130 and the surface of the first shield member 130 facing the planar coil 110, and is in contact with the surface of the first shield member 130 facing the planar coil 110. In the illustrated example, a groove 124 (see FIG. 9 ) is formed on the surface of the spacer member 120 facing the first shield member 130, and the first conductor portion 161A is passed through the groove 124. This prevents the first conductor portion 161A from protruding. The first conductor portion 161A is positioned to cover the gap between the first shield piece 131 and the eighth shield piece 138 that constitute the first shield member 130.

[0115] In the present embodiment, the spacer member 120 is magnetic, but the spacer member 120 may be non-magnetic and insulating, for example, and may be made of resin only. Also, the spacer member 120 may not be provided, and an air layer may be formed between the planar coil 110 and the first shield member 130.

[0116] In the second embodiment described above, the distance between the first conductor portion 161A and the planar coil 110 is partially increased at least at the portion of the eighth turn portion 1108 that intersects with the first conductor portion 161A, and other portions of the eighth turn portion 1108 do not protrude. This prevents the coil component 102 from becoming larger due to the addition of a configuration for suppressing dielectric breakdown or short-circuiting. This allows the coil component 102 to be suppressed from becoming larger or to be made smaller while preventing dielectric breakdown or short-circuiting that may occur in the coil component 100.

[0117] Furthermore, in this embodiment, the first conductor portion 161A is disposed between the planar coil 110 and the first shield member 130. This allows for a compact layout of the first conductor portion 161A. The first conductor portion 161A contacts the surface of the first shield member 130 facing the planar coil 110. In this case, a large distance can be secured between the first conductor portion 161A and the second shield member 150. This allows for a reduction in size and thickness, for example, by reducing the thickness of the first shield member 130 and bringing the second shield member 150 closer to the first shield member 130, while suppressing dielectric breakdown or short-circuiting between the first conductor portion 161A and the second shield member 150. On the other hand, if the first conductor portion 161A contacts the surface of the first shield member 130 facing the planar coil 110, the first conductor portion 161A may approach the planar coil 110. To address this issue, the distance between the first conductor portion 161A and the planar coil 110 is partially increased at least at the portion where the eighth turn portion 1108 intersects with the first conductor portion 161A, thereby effectively suppressing the problem of insulation breakdown or short circuit between the first conductor portion 161A and the planar coil 110.

[0118] <<Simulation of Performance Evaluation>> Fig. 11 shows the simulation results of the electric field strength when a current is supplied to the coil device 100 according to the first embodiment. Fig. 12 shows the simulation results of the electric field strength when a current is supplied to the coil device 102 according to the second embodiment.

[0119] The horizontal axis of the graphs in Figures 11 and 12 represents the distance from the center of first conductor portion 161A to the center of planar coil 110, and the vertical axis represents the electric field strength (V / m) between first conductor portion 161A and planar coil 110.

[0120] 11 , the dashed line indicated by symbol E1 represents the electric field strength between first conductor portion 161A and planar coil 110 when an 85 kHz AC current is supplied to coil component 100 according to the first embodiment. The solid line indicated by symbol E2 represents the electric field strength between first conductor portion 161A and planar coil 110 when an 85 kHz AC current is supplied to a modified version of coil component 100 according to the first embodiment. In this modified version, spacer member 120 is not provided, and an air layer is formed between planar coil 110 and first shield member 130.

[0121] 11, the symbol Co indicates the electric field strength (V / m) between the portion corresponding to first conductor portion 161A and the portion corresponding to planar coil 110 when an 85 kHz AC current is supplied to the coil component according to the comparative example. In the comparative example, the distance between the portion corresponding to first conductor portion 161A and the portion corresponding to planar coil 110 is constant, and this distance corresponds to the distance CL1 shown in FIG. 5. Lines E1, E2, and Co indicate that the electric field strength increases where the conductor portion intersects with the turn portion, and then increases stepwise as it moves radially outward. Note that lines E1 and E2 partially indicate the portion including the peak of the electric field strength.

[0122] The AC current value and frequency set in the simulations are the same. As is clear from a comparison of lines E1, E2, and Co, in coil device 100 according to the first embodiment, the distance between first conductor portion 161A and turn portions 1102 to 1108 that intersect with it is made larger than in the comparative example, thereby significantly suppressing the electric field strength between first conductor portion 161A and planar coil 110 compared to the comparative example. These results also confirm the effects of the first embodiment.

[0123] 12 , the dashed dotted line indicated by symbol E1′ indicates the electric field strength between first conductor portion 161A and planar coil 110 when an 85 kHz AC current is supplied to coil component 102 according to the second embodiment. The solid line indicated by symbol E2′ indicates the electric field strength between first conductor portion 161A and planar coil 110 when an 85 kHz AC current is supplied to a modified example of coil component 100 according to the second embodiment. In this modified example, spacer member 120 is not provided, and an air layer is formed between planar coil 110 and first shield member 130.

[0124] 11, the symbol Co in Fig. 12 indicates the electric field strength (V / m) between the portion corresponding to first conductor portion 161A and the portion corresponding to planar coil 110 when an 85 kHz AC current is supplied to the coil component according to the comparative example. Note that lines E1' and E2' partially indicate the portions including the peaks of the electric field strength.

[0125] The AC current value and frequency set in the simulations are the same. As is clear from a comparison of lines E1, E2, and Co, in coil device 102 according to the second embodiment, the distance between first conductor portion 161A and turn portions 1102 to 1108 that intersect with it is made larger than in the comparative example, thereby significantly suppressing the electric field strength between first conductor portion 161A and planar coil 110 compared to the comparative example. These results also confirm the effects of the second embodiment.

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

Claims

1. A coil component comprising: a planar coil including a plurality of turn portions arranged in the radial direction; and a conductor portion connected to an inner end of a turn portion located innermost in the radial direction of the planar coil and extending radially outward so as to intersect with the plurality of turn portions in sequence, wherein the distance in the axial direction of the planar coil between a turn portion located outermost in the radial direction among the plurality of turn portions and the conductor portion is greater than the distance in the axial direction between a connection portion of the turn portion located innermost in the radial direction with the conductor portion and the conductor portion.

2. The coil component according to claim 1, wherein the distance between the plurality of turn portions and the conductor portion increases toward the outside in the radial direction.

3. The coil component according to claim 1, wherein the plurality of turn portions are positioned so as to be arranged on the same plane, and the conductor portion extends so as to be inclined with respect to the plane.

4. A coil component as described in claim 1 or 2, comprising a first shielding member that is overlapped with said planar coil and has magnetic and insulating properties, and said conductor portions extend such that the distance in the axial direction from said first shielding member increases as they extend radially outward.

5. A coil component as described in claim 1, wherein at least the turn portion located outermost in the radial direction among the plurality of turn portions is bent so as to move away from the conductor portion at a position where it intersects with the conductor portion.

6. The coil component according to claim 5, wherein all of said plurality of turn portions that intersect with said conductor portion are bent away from said conductor portion at the positions where they intersect with said conductor portion.

7. A coil component as described in claim 5 or 6, comprising a first shielding member overlapping said planar coil and having magnetic and insulating properties, wherein said turn portion is bent so as to be away from said conductor portion at a position where it intersects with said conductor portion, and is bent so as to be away from said first shielding member.

8. A coil component as described in claim 1, wherein the turn portion located most inward in the radial direction and the conductor portion are connected via a conductive connecting portion, and the distance in the axial direction between the turn portion located most outward in the radial direction and the conductor portion is greater than a thickness of the conductive connecting portion.

9. The coil component according to claim 1, further comprising a first shield member overlapping said planar coil and having magnetic and insulating properties.

10. The coil component according to claim 9, wherein the conductor portion is disposed on a side of the planar coil opposite to the side of the first shield member.

11. The coil component according to claim 10, wherein the conductor portion is disposed between the planar coil and the first shield member.

12. The coil component according to claim 11, wherein the conductor portion is in contact with a surface of the first shield member that faces the planar coil.

13. The coil component according to any one of claims 9 to 12, wherein the first shielding member includes ferrite.

14. The coil component according to claim 9, further comprising a second shielding member which is non-magnetic and conductive and is overlaid on the first shielding member so as to face a surface of the first shielding member opposite the surface facing the planar coil.

15. The coil component according to claim 14, wherein the second shield member includes aluminum or an aluminum alloy.

16. A power transmission device comprising the coil component according to claim 1.

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

18. A power transmission system comprising a power transmitting device and a power receiving device, at least one of the power transmitting device and the power receiving device comprising the coil component described in claim 1.

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