Coil unit, power transmission device, power reception device, power transmission system, and movable body

Abstract

To provide a coil unit, a power transmission device, a power reception device, a power transmission system, and a movable body that achieve efficient power transmission in a wireless power transmission system.SOLUTION: A coil unit 5 comprises: a coil 10 that includes a coil element 10i formed spirally around an arbitrary central axis C; a first shield member 30; and an outer frame 70 that circumferentially extends on the outside of the coil 10. The coil 10 has a first principal surface 10a, and a second principal surface 10b that is a surface on the opposite side of the first principal surface 10a. The first shield member 30 and the coil 10 are laminated in this order in a first direction AD1 directed from the second principal surface 10b to the first principal surface 10a. The outer frame 70 includes ferrite. The outer frame 70 projects in the first direction beyond the first principal surface 10a of the coil 10.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

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

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

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

[0005] An object of the present disclosure is to achieve efficient power transmission. [Means for solving the problem]

[0006] One embodiment of the present disclosure relates to the following [1] to

[32] .

[0007] [1] A coil including coil elements formed in a spiral shape around a central axis, a first shield member, and an outer frame extending circumferentially around the outside of the coil, The coil has a first main surface and a second main surface that is a surface opposite to the first main surface, the first shield member and the coil are laminated in this order in a first direction from the second main surface to the first main surface, The outer frame includes ferrite and protrudes in the first direction beyond the first main surface of the coil.

[0008] [2] Further comprising an inner frame extending circumferentially inside the coil, The coil unit described in [1], wherein the inner frame includes ferrite and protrudes in the first direction beyond the first main surface of the coil.

[0009] [3] A coil unit as described in [1] or [2], wherein, when viewed in the axial direction, the outer frame is positioned inside the outer edge of the first shielding member.

[0010] [4] A first connection terminal connected to the coil, the coil has an inner end proximate the central axis and an outer end distal to the central axis; the first connection terminal is connected to the inner end of the coil and extends from the inner side to the outer side of the coil when viewed in the axial direction; The coil unit according to any one of [1] to [3], wherein the outer frame has a discontinuous portion that overlaps with the first connection terminal when viewed in the axial direction.

[0011] [5] The first shield member is divided into a plurality of shield pieces, The first shield member has a gap extending linearly between adjacent shield pieces, the gap extending from the inside to the outside of the coil when viewed in the axial direction, The coil unit according to any one of [1] to [4], wherein the outer frame has a discontinuous portion that overlaps with the gap when viewed in the axial direction.

[0012] [6] The coil unit according to [4] or [5], wherein the width of the discontinuous portion is 0.8 mm or more.

[0013] [7] The coil unit according to any one of [4] to [6], wherein the width of the discontinuous portion is 5 mm or more.

[0014] [8] The coil unit according to any one of [1] to [7], wherein the relative magnetic permeability of the outer frame is 1000 or more.

[0015] [9] The coil unit according to any one of [1] to [8], wherein a protruding height of the outer frame protruding in the first direction beyond the first main surface is 1 mm or more.

[0016]

[10] The coil unit according to any one of [1] to [9], wherein the width of the outer frame is 3 mm or more and 10 mm or less.

[0017]

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

[10] , wherein the distance between the outer frame and the coil is 3 mm or less when viewed in the axial direction.

[0018]

[12] The coil unit according to [2], wherein the distance between the inner frame and the coil is 3 mm or less when viewed in the axial direction.

[0019]

[13] The coil unit according to [2], wherein the inner frame has a relative magnetic permeability of 1000 or more.

[0020]

[14] A coil including a coil element formed in a spiral shape around a central axis, a first shield member, and an inner frame extending circumferentially inside the coil, The coil has a first main surface and a second main surface that is a surface opposite to the first main surface, the first shield member and the coil are laminated in this order in a first direction from the second main surface to the first main surface, The inner frame includes ferrite and protrudes in the first direction beyond the first main surface of the coil.

[0021]

[15] The coil unit according to

[14] , wherein the inner frame has a relative magnetic permeability of 1000 or more.

[0022]

[16] The coil unit according to

[14] or

[15] , wherein the inner frame protrudes in the first direction beyond the first main surface by a height of 1 mm or more.

[0023]

[17] The coil unit according to any one of

[14] to

[16] , wherein the width of the inner frame is 3 mm or more and 10 mm or less.

[0024]

[18] The coil unit according to any one of

[14] to

[17] , wherein the distance between the inner frame and the coil is 3 mm or less when viewed in the axial direction.

[0025]

[19] The coil unit according to any one of [1] to

[18] , wherein the first shielding member contains ferrite.

[0026]

[20] The coil unit according to any one of [1] to

[19] , wherein the first shield member is divided into a plurality of small shield pieces.

[0027] [twenty one] The coil unit includes a magnetic resin layer that is in direct contact with the second main surface of the coil. The coil unit according to

[20] .

[0028] [twenty two] The coil unit according to

[21] , wherein the magnetic resin layer has a relative magnetic permeability of 5 or more and 30 or less.

[0029] [twenty three] A first connection terminal connected to the coil, the coil has an inner end proximate the central axis and an outer end distal to the central axis; the first connection terminal is connected to the inner end portion on the second main surface side of the coil and extends from the inner side to the outer side of the coil when viewed in the axial direction; The first shield member is divided into a plurality of shield pieces, The first shield member has a gap extending linearly between adjacent shield pieces, the gap extending from the inside to the outside of the coil, The coil unit according to any one of [1] to

[22] , wherein the first connection terminal extends within the gap when viewed in the axial direction.

[0030] [twenty four] The coil unit described in

[23] , wherein the first connection terminal extends from the inside to the outside of the coil at a height position where it overlaps with the first shield member in a side view of the coil unit.

[0031] [twenty five] A first connection terminal connected to the coil, the coil has an inner end proximate the central axis and an outer end distal to the central axis; the first connection terminal is connected to the inner end portion on the second main surface side of the coil and extends from the inner side to the outer side of the coil when viewed in the axial direction; The first shield member has a notch formed therein, the notch extending from the inside to the outside of the coil as viewed in the axial direction, The coil unit according to any one of [1] to

[22] , wherein the first connection terminal extends within the notch when viewed in the axial direction.

[0032]

[26] The coil unit described in

[25] , wherein the first connection terminal extends from the inside to the outside of the coil at a height position where it overlaps with the first shielding member in a side view of the coil unit.

[0033]

[27] the coil element winds around the central axis in a first winding direction from an inner end to an outer end, A coil unit as described in

[23] or

[24] , wherein the area of ​​the shield piece adjacent to the first connection terminal in the first winding direction is greater than or equal to the area of ​​the shield piece adjacent to the first connection terminal on either side of the shield piece.

[0034]

[28] the coil element winds around the central axis in a first winding direction from an inner end to an outer end, A coil unit as described in

[23] or

[24] , wherein the area of ​​the shield piece adjacent to the first connection terminal in the first winding direction is greater than or equal to the area of ​​the shield piece adjacent to the first connection terminal in the first winding direction.

[0035]

[29] A power transmitting device comprising the coil unit according to any one of [1] to

[28] .

[0036]

[30] A power receiving device comprising the coil unit according to any one of [1] to

[28] .

[0037]

[31] The power transmission device and the power receiving device are provided. A power transfer system, wherein at least one of the power transmitting device and the power receiving device is provided with the coil unit according to any one of [1] to

[28] .

[0038]

[32] A moving body comprising the coil unit according to any one of [1] to

[28] . Effect of the Invention

[0039] According to an embodiment of the present disclosure, efficient power transmission can be achieved. [Brief description of the drawings]

[0040] [Figure 1]FIG. 1 is a diagram illustrating a schematic diagram of a wireless power transmission system to which a coil unit according to an embodiment can be applied. [Diagram 2] FIG. 2 is a perspective view of a coil unit used in the wireless power transmission system shown in FIG. [Diagram 3] FIG. 3 is an exploded perspective view of the coil unit shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the coil unit taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a plan view of the coil unit shown in FIG. [Figure 6] FIG. 6 is an enlarged view of the area surrounded by the two-dot chain line in FIG. [Figure 7] FIG. 7 corresponds to FIG. 6 and shows a modified example of the coil unit. [Figure 8] FIG. 8 corresponds to FIG. 6 and shows another modified example of the coil unit. [Figure 9] FIG. 9 corresponds to FIG. 5 and shows still another modified example of the coil unit. [Figure 10] FIG. 10 corresponds to FIG. 2 and shows still another modified example of the coil unit. [Figure 11] FIG. 11 is an exploded perspective view of the coil unit shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view of the coil unit taken along line XII-XII in FIG. [Figure 13] FIG. 13 is a plan view of the coil unit shown in FIG. [Figure 14] FIG. 14 is a table showing the results of simulation 1. [Figure 15] FIG. 15 is a table showing the results of simulation 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] An embodiment and its modified examples will be described below with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0042] In addition, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely on the basis of differences in name. Thus, for example, "sheet" is a concept that includes members that may also be called films and plates.

[0043] Fig. 1 shows a schematic diagram of a wireless power transmission system S to which a coil unit 5 according to an embodiment is applied. First, the wireless power transmission system S (hereinafter, abbreviated as power transmission system S) will be described with reference to Fig. 1. It goes without saying that a coil unit different from the coil unit 5 according to the present embodiment can be applied to the power transmission system S.

[0044] <Wireless power transmission system> The power transmission system S includes a power transmitting device 1 and a power receiving device 2. The power transmitting device 1 includes a coil unit 5 and a high-frequency current supplying unit 1A. The coil unit 5 in the power transmitting device 1 functions as a power transmitting coil unit. The high-frequency current supplying unit 1A supplies a high-frequency current to the coil unit 5 serving as a power transmitting coil unit.

[0045] The power receiving device 2 includes a coil unit 5 and a conversion unit 2A. The coil unit 5 in the power receiving device 2 functions as a power receiving coil unit. The conversion unit 2A shapes a high-frequency current generated in the coil unit 5. The conversion unit 2A has a rectifier circuit that converts the high-frequency current into a direct current, and the like. The conversion unit 2A may include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0046] In this embodiment, each of the power transmitting device 1 and the power receiving device 2 includes a coil unit 5. However, the coil unit 5 may be used in only one of the power transmitting device 1 and the power receiving device 2, and a different type of coil unit may be used in the other.

[0047] 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 unit 5 serving as a power transmitting coil unit. At this time, a magnetic field is generated in the coil unit 5 by electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil unit 5 serving as a power receiving coil unit in the power receiving device 2. That is, the power receiving device 2 receives a magnetic field from the power transmitting device 1 or is influenced by the magnetic field in the power transmitting device 1, and causes a 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.

[0048] The power transmission system S shown in Fig. 1 employs a magnetic resonance method as a power transmission method. However, the coil unit 5 according to the present embodiment may be used in a power transmission system that employs an electromagnetic induction method. The power transmission system S is configured as a system that wirelessly transmits power to an electric vehicle. In this case, the power transmitting device 1 is installed on a road, a parking lot, or the like. The power receiving device 2 is installed in the electric vehicle.

[0049] However, the use of the power transmission system S is not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to flying objects such as drones and robots. The power transmission system S may also be used to transmit power to submersibles and exploration robots in the sea. In this way, the power transmission system S can be used to transmit power to various moving objects such as electric vehicles, flying objects, robots, and submersibles. The use of the coil unit 5 is not limited to wireless power transmission systems. For example, the coil unit 5 may be used in transformers, DC-DC converters, antennas, and the like.

[0050] The coil unit 5 according to this embodiment will be described below.

[0051] <Coil unit> FIG. 2 is a perspective view of the coil unit 5 according to the present embodiment. FIG. 3 is an exploded perspective view of the coil unit 5. FIG. 4 is a cross-sectional view of the coil unit 5 taken along line IV-IV in FIG. 2. FIG. 5 is a plan view of the coil unit 5. A magnetic resin layer 20, which will be described later, is omitted in FIGS. 3 and 5. Also, a magnetic wall portion 25, which will be described later, is omitted in FIG. 5. FIG. 6 is an enlarged view of a portion surrounded by a two-dot chain line in FIG. 5.

[0052] As shown in FIGS. 2 to 5, the coil unit 5 includes a coil 10, a first shielding member 30, an inner frame 60, and an outer frame 70. In the illustrated example, the coil unit 5 further includes a magnetic resin layer 20, a magnetic wall portion 25, a second shielding member 50, a first connection terminal 56, and a second connection terminal 57. As shown in FIG. 4, the coil 10 has a first main surface 10a and a second main surface 10b. The second main surface 10b is the surface opposite to the first main surface 10a. The second shielding member 50, the first shielding member 30, the coil 10, and the magnetic resin layer 20 are arranged in this order in a direction from the second main surface 10b toward the first main surface 10a. Hereinafter, the direction from the second main surface 10b toward the first main surface 10a is also referred to as a "first stacking direction AD1". Furthermore, in the following, the terms "first side" and "second side" used with respect to the coil unit 5 and its components refer to the side located in the first stacking direction AD1 and the side located in the direction opposite to the first stacking direction AD1 (i.e., the direction from the first main surface 10a to the second main surface 10b), respectively, when viewed from the coil unit 5 and its components.

[0053] (coil) As shown in Fig. 5, the coil 10 includes coil elements 10i 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 approaches 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.

[0054] Hereinafter, the axial direction means a direction extending on the central axis C or a direction parallel to the central axis C. Additionally, the radial direction means the radial direction of a circle drawn on a plane centered on an arbitrary point on the central axis C and perpendicular to the central axis C. Additionally, the circumferential direction means a direction along a circle centered on the central axis C (the circumferential direction of the circle).

[0055] The coil element 10i is made of a conductive material. In the present embodiment, the coil element 10i is made of copper, but is not limited to this. The coil element 10i may be made of a copper alloy, aluminum, an aluminum alloy, or the like.

[0056] In the example shown in Figures 2 to 6, the coil 10 is composed of a single coil element 10i. The coil element 10i is plate-shaped. That is, the coil element 10i is a planar coil. More specifically, the coil element 10i is a planar coil element made of a non-litz wire. As shown in Figure 4, the cross-sectional shape of the conductor of the coil element 10i in a direction perpendicular to the winding direction of the spiral shape is rectangular.

[0057] The coil element 10i includes a conductor 10E having a spiral shape. The conductor 10E includes a plurality of turn portions 10n arranged in a radial direction. The plurality of turn portions 10n are arranged in a direction perpendicular to a central axis C of the spiral shape. More specifically, the plurality of turn portions 10n are connected so as to gradually move away from the central axis C in a radially outward direction. As a result, the plurality of turn portions 10n form a spiral shape as a whole.

[0058] More specifically, the turn portion 10n is basically a shape in which a linear conductor portion does not form a loop but goes around the central axis C 360 degrees. In the case of a so-called planar coil, both ends of the turn portion 10n are offset in the radial direction. In the case of multiple turn portions 10n, the radially outer end of one turn portion 10n is connected to the radially inner end of another turn portion 10n. As a result, the multiple turn portions 10n as a whole extend away from the central axis C.

[0059] Hereinafter, of the multiple turn portions 10n, the one closest to the central axis C may be referred to as the turn portion 101. Also, the turn portion connected to the turn portion 101 may be referred to as the turn portion 102. In the following, when describing matters common to each of the multiple turn portions 10n, they will basically be referred to as the turn portion 10n.

[0060] In this embodiment, the turn portion 10n winds around to form a polygon. In this specification and disclosure, the spiral shape refers to a planar curved shape wound in a spiral shape. The planar curved shape here 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 approaches the center as it turns).

[0061] In the illustrated example, the conductor 10E of the coil element 10i includes the first to eighth turn portions 101 to 108. The first to eighth turn portions 101 to 108 are arranged in this order from the inside to the outside in the radial direction. In other words, the first turn portion 101 is located at the innermost position in the radial direction, and the eighth turn portion 108 is located at the outermost position in the radial direction. In other words, the first turn portion 101 forms the innermost portion of the coil element 10i. Also, the eighth turn portion 108 forms the outermost portion of the coil element 10i. Note that the radial inner side of a certain member means a position closer to the central axis C than the member. Also, the radial outer side of a certain member means a position farther outward in the radial direction than the member. For example, when it is said that the "radial inner side of the coil element 10i" is mentioned, this means a position closer to the central axis C than the innermost turn portion 101. When we say "radially outward from the coil element 10i," this means a position that is farther outward from the outermost turn portion 108 in the radial direction.

[0062] Each of the turn portions 101 to 108 extends on the above-mentioned imaginary plane. The first to eighth turn portions 101 to 108 are connected in this order, and the coil element 10i thereby forms a spiral shape. In the illustrated example, the coil element 10i is octagonal as a whole. The coil element 10i (the conductor 10E) is wound so that each of the turn portions 101 to 108 forms a roughly octagonal shape. However, the shape of the coil element 10i is not limited thereto. The coil element 10i may be a polygonal shape other than an octagonal shape (for example, a square shape, a hexagonal shape, or a dodecagonal shape) as a whole. In this case, each of the turn portions 101 to 108 may be wound so as to roughly form a polygonal shape other than an octagon (for example, a square shape, a hexagonal shape, or a dodecagonal shape). The coil element 10i may also be a circular shape as a whole. In this case, each of the turn portions 101 to 108 may be wound so as to form a roughly circular shape.

[0063] One end of each of the turn portions 101 to 108 is located radially inward from the other end of the turn portion 101 to 108. In other words, the other end of each of the turn portions 101 to 108 is located radially outward from the one end of the turn portion 101 to 108.

[0064] Each of the turn portions 101-108 includes a plurality of straight portions 11-18 arranged around the central axis C. The straight portions 11-18 adjacent to each other in the circumferential direction of the circle centered on the central axis C are connected to each other. In the illustrated example, the first to eighth turn portions 101-108 include first to eighth straight portions 11-18. The first to eighth straight portions 11-18 are lined up in this order along the circumferential direction.

[0065] The first straight line portion 11 and the fifth straight line portion 15 extend in a first direction D1. The second straight line portion 12 and the sixth straight line portion 16 extend in a second direction D2. The third straight line portion 13 and the seventh straight line portion 17 extend in a third direction D3. The fourth straight line portion 14 and the eighth straight line portion 18 extend in a fourth direction D4. The first direction D1, the second direction D2, the third direction D3, and the fourth direction D4 are non-parallel to each other.

[0066] In each of the turn portions 101 to 108, adjacent ends of the straight portions 11, 12; 12, 13; 13, 14; 14, 15; 15, 16; 16, 17; 17, 18 adjacent to each other in the circumferential direction are connected to each other. For example, the first straight portion 11 and the second straight portion 12 of the first turn portion 101 are connected to each other. The second straight portion 12 and the third straight portion 13 of the first turn portion 101 are connected to each other. In each of the turn portions 101 to 108, adjacent ends of the straight portions 11, 12; 12, 13; 13, 14; 14, 15; 15, 16; 16, 17; 17, 18 adjacent to each other in the circumferential direction may be connected to each other via a curved portion that curves along the circumferential direction.

[0067] Furthermore, the eighth straight portion 18 and the first straight portion 11 of the radially adjacent turn portions 101, 102;...; 107, 108 are connected to each other. For example, the circumferentially adjacent ends of the eighth straight portion 18 of the first turn portion 101 and the first straight portion 11 of the second turn portion 102 are connected to each other. The circumferentially adjacent ends of the eighth straight portion 18 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103 are connected to each other. The eighth straight portion 18 and the first straight portion 11 of the radially adjacent turn portions 101, 102;...; 107, 108 may be connected to each other via a curved portion that curves along the circumferential direction.

[0068] The first straight portions 11 of the turn portions 101-108 are arranged in the radial direction to form a first straight portion group 11G. The second straight portions 12 of the turn portions 101-108 are arranged in the radial direction to form a second straight portion group 12G. The third straight portions 13 of the turn portions 101-108 are arranged in the radial direction to form a third straight portion group 13G. The fourth straight portions 14 of the turn portions 101-108 are arranged in the radial direction to form a fourth straight portion group 14G. The fifth straight portions 15 of the turn portions 101-108 are arranged in the radial direction to form a fifth straight portion group 15G. The sixth straight portions 16 of the turn portions 101-108 are arranged in the radial direction to form a sixth straight portion group 16G. The seventh straight portions 17 of the turn portions 101-108 are arranged in the radial direction to form a seventh straight portion group 17G. The eighth straight portions 18 of the multiple turn portions 101-108 are arranged in the radial direction to form an eighth straight portion group 18G. The straight portions 11, 11; 12, 12; 13, 13; 14, 14; 15, 15; 16, 16; 17, 17; and 18, 18 that are adjacent to each other in the radial direction are spaced apart from each other in the radial direction.

[0069] The first straight line group 11G and the fifth straight line group 15G are arranged so that the central axis C passes therebetween. The second straight line group 12G and the sixth straight line group 16G are arranged so that the central axis C passes therebetween. The third straight line group 13G and the seventh straight line group 17G are arranged so that the central axis C passes therebetween. The fourth straight line group 14G and the eighth straight line group 18G are arranged so that the central axis C passes therebetween.

[0070] Furthermore, in the illustrated example, the coil 10 has a regular octagonal shape as a whole when viewed in the axial direction. In other words, the coil element 10i (the conductor 10E) is wound so that the turn portions 101-108 form a regular octagon. The coil element 10i includes eight straight line portion groups 11G-18G extending along eight sides of the regular octagon. According to the knowledge obtained by the present inventors, when the coil 10 has an octagonal shape as a whole, the performance of the coil unit 5 can be improved by making the shape of the coil 10 closer to a regular octagon.

[0071] The coil element 10i described above is formed, for example, by punching a metal plate such as a copper plate or an aluminum plate into a spiral shape. Alternatively, the coil element 10i can also be formed by etching a metal foil such as a copper foil or an aluminum foil into a spiral shape.

[0072] The radius of the coil element 10i (the distance from the central axis C to the part furthest from the center axis C in the radial direction) may be 80 mm or more and 450 mm or less. When the coil 10 is used in a power transmitting coil unit or a power receiving coil unit of a power transmission system S that transmits power to an electric vehicle by a magnetic field resonance method, the radius of the coil element 10i is usually 200 mm or more and 350 mm or less.

[0073] The thickness of the coil element 10i (thickness of the conductor 10E) is measured along the axial direction of the coil element 10i. The thickness of the coil element 10i (thickness of the conductor 10E) may be, for example, 0.1 mm or more and 2.0 mm or less, 0.2 mm or more and 1.0 mm or less, or 0.3 mm or more and 10.7 mm or less. The thickness of the coil element 10i (conductor 10E) may be, for example, 0.15 mm or more and 0.35 mm or less. When transmitting power to an electric vehicle using the magnetic field resonance method, it is desirable to be able to transmit power of 1 kW or more, preferably 5 kW or more, in a high-frequency current frequency range of 10 kHz to 200 kHz, particularly 79 kHz to 90 kHz. In this case, the thickness of the coil element 10i made of copper is preferably 0.4 mm or more.

[0074] The line width of the conductor 10E in the coil element 10i is not particularly limited. However, in consideration of being able to transmit power of 1 kW or more, preferably 5 kW or more, in a high-frequency current frequency range of, for example, 79 kHz to 90 kHz, the line width of each turn portion 101 to 108 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 means the distance between the inner peripheral surface and the outer peripheral surface of the conductor 10E in a cross section perpendicular to the direction in which the conductor 10E turns.

[0075] The aspect ratio of the coil element 10i (conductor 10E) having a rectangular cross-sectional shape is determined by dividing the line width (the radial width of each turn portion 10n) of the coil element 10i (conductor 10E) by the thickness of the coil element 10i (conductor 10E). The aspect ratio of the coil element 10i (conductor 10E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0076] The thickness and line width of the conductor 10E may be measured by measuring each part of the conductor 10E with a ruler or the like in a cross section obtained by cutting the coil unit 5 in the axial direction to expose the conductor 10E, or by analyzing a cross section image. Also, the coil element 10i may be removed from the coil unit 5, and the thickness of the conductor 10E may be measured with a ruler, calipers, or the like. Similarly, the dimensions of the other members of the coil unit 5 may be measured by measuring the cross section with a ruler or the like, or by analyzing a cross section image.

[0077] The coil 10 has an end 10e1 to which the first connection terminal 56 is connected and an end 10e2 to which the second connection terminal 57 is connected. In the illustrated example, the coil 10 is composed of a single coil element 10i. Therefore, one end 10e1 is an inner end located radially inward of the coil 10. The other end 10e2 is an outer end located radially outward of the coil 10. The inner end 10e1 is an end of the first turn portion 101 of the coil element 10i. The outer end 10e2 is an end of the eighth turn portion 108 of the coil element 10i. The inner end 10e1 is closer to the central axis C than the outer end 10e2. In other words, the outer end 10e2 is farther from the central axis C than the inner end 10e1.

[0078] In the example shown in Fig. 2 to Fig. 6, the pitches of the second to eighth turn portions 102 to 108 are equal. However, as shown in Fig. 5, the distance between the inner end portion 10e1 of the coil element 10i and the first straight portion 11 of the second turn portion 102 is greater than the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. More specifically, the distance between the inner end region of the coil element 10i including the inner end portion 10e1 (the first straight portion 11 of the first turn portion 101 in the example shown in Fig. 2 to Fig. 6) and the first straight portion 11 of the second turn portion 102 is greater than the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. According to the findings of the present inventors, in an example in which the first connection terminal 56 is connected to the inner end 10e1 of the coil element 10i, the inner end 10e1 is spaced apart from the second turn portion 102, thereby suppressing losses in the coil unit 5. In particular, the iron loss of the shield piece 31 that overlaps with the inner end region of the coil element 10i as viewed in the axial direction can be effectively suppressed. Here, the iron loss refers to loss caused by the magnetic flux of the first shield member 30. Of course, the distance between the inner end 10e1 of the coil element 10i and the first straight portion 11 of the second turn portion 102 may be equal to the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. In other words, the pitches of the first to eighth turn portions 101 to 108 may be equal to each other.

[0079] In this embodiment, the central axis C is determined as follows. First, linear virtual turn portions similar in shape to the second turn portion 102 are drawn in sequence from the radially inner end of the second turn portion 102 to form a spiral shape radially inward. Drawing is continued until a virtual turn portion that fits within a diameter of 1 cm is drawn. Then, a line that passes through the radially inner region of the virtual turn portion that fits within a diameter of 1 cm, in a direction perpendicular to the circumferential and radial directions of the spiral shape, is determined as the central axis C.

[0080] (Magnetic resin layer) The magnetic body resin layer 20 is provided to suppress magnetic permeation and / or leakage magnetic field. The magnetic body resin layer 20 overlaps with the coil 10 in the axial direction of the coil 10. In this state, the magnetic body resin layer 20 is in direct contact with the second main surface 10b of the coil 10. In other words, the magnetic body resin layer 20 is in direct contact with the conductor 10E. In the illustrated example, the magnetic body resin layer 20 is in close contact with the second main surface 10b of the coil 10. In other words, the magnetic body resin layer 20 is in close contact with the conductor 10E. In the illustrated example, the magnetic body resin layer 20 is formed so that its outer edge is located outside the coil 10 when viewed in the axial direction.

[0081] The magnetic resin layer 20 has magnetism. The magnetic field generated in the coil unit 5 is generated so as to spread in all directions with respect to the central axis C of the coil 10. At this time, the magnetic resin layer 20 has magnetism, and can orient the spreading magnetic flux lines toward the central axis C. Also, if the magnetic field generated in the coil unit 5 reaches peripheral components located around the coil unit 5, the peripheral components may be adversely affected. Therefore, the magnetic resin layer 20 is provided to suppress the magnetic lines from reaching the peripheral components. As a result, the magnetic resin layer 20 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0082] The magnetic resin layer 20 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.

[0083] As the resin for forming the holding material of the magnetic resin layer 20, for example, a thermosetting resin such as epoxy resin or polyimide can be adopted. In this case, when the coil 10 and the magnetic resin layer 20 are integrated by heat pressing as described later, the resin of the magnetic resin layer 20 can be easily deformed along the shape of the coil 10 during the heat curing process. In addition, a thermoplastic resin such as nylon, polyethylene, polypropylene, etc. can also be adopted as the resin for forming the magnetic resin layer 20. In this case, too, it is easy to deform the resin of the magnetic resin layer 20 along the shape of the coil 10. In addition, the holding material may include, for example, a fiber reinforced plastic or may be formed from a fiber reinforced plastic. For example, the holding material may include, or be formed from a glass fiber reinforced polyamide.

[0084] The magnetic particles of the magnetic resin layer 20 may be made of any one or more of ferrite, particularly soft magnetic ferrite, nanocrystalline magnetic material, silicon steel, soft magnetic iron, and amorphous metal.

[0085] As shown in FIG. 4, the magnetic resin layer 20 has a spiral-shaped recess 22 corresponding to the spiral shape of the coil 10. The recess 22 is a portion of the magnetic resin layer 20 recessed in the axial direction of the coil 10, in other words, in the thickness direction of the magnetic resin layer 20. The recess 22 has a spiral shape when viewed in the axial direction of the coil 10. At least a part of the coil 10 is accommodated in the recess 22 with its spiral shape aligned with the spiral shape of the recess 22. More specifically, the recess 22 accommodates the entire conductor 10E. For this reason, as shown in FIG. 4, the magnetic resin layer 20 is in direct contact with three surfaces of the coil 10 other than the first main surface 10a.

[0086] In this embodiment, the conductor 10E does not protrude from the magnetic substance resin layer 20. In other words, the first main surface 10a of the coil 10 and the surface of the magnetic substance resin layer 20 facing the first side are flush with each other. However, only a part of the coil 10 may be housed in the recess 22 so that a part of the coil 10 protrudes from the magnetic substance resin layer 20. Also, the recess 22 may not be formed in the magnetic substance resin layer 20, and the coil 10 may be provided on the flat surface of the magnetic substance resin layer 20. Also, the conductor 10E may be embedded in the magnetic substance resin layer 20 without being exposed to the outside.

[0087] As described above, in the illustrated example, the magnetic body resin layer 20 is in close contact with the second main surface 10b of the coil 10. Specifically, the magnetic body resin layer 20 is welded to the coil 10 at the recess 22. That is, the coil 10 and the magnetic body resin layer 20 are joined by the anchor effect at the recess 22. The coil 10 and the magnetic body resin layer 20 are integrated together by, for example, heat pressing. At this time, a part of the magnetic body resin layer 20 enters the recess on the surface of the coil 10 and then hardens. As a result, the coil 10 and the magnetic body resin layer 20 are welded together, and the magnetic body resin layer 20 is in close contact with the coil 10.

[0088] The magnetic substance-resin layer 20 may be divided into a plurality of parts, similar to the first shield member 30 described below. In this case, the magnetic substance-resin layer 20 may include a plurality of magnetic substance-resin elements.

[0089] The relative magnetic permeability of the magnetic substance resin layer 20 is preferably 2.0 or more, and may be 2.0 or more and 20.0 or less. The relative magnetic permeability of the magnetic substance resin layer 20 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 magnetic substance resin layer 20 is not particularly limited, but if it is too large, the flexibility and strength of the magnetic substance resin layer 20 may be undesirably impaired. Therefore, the relative magnetic permeability of the magnetic substance resin layer 20 may be 30 or less.

[0090] (Magnetic wall) As shown in Fig. 4, the magnetic wall portion 25 protrudes in the first stacking direction AD1 beyond the first main surface 10a of the coil 10. As can be seen from Fig. 2 and Fig. 4, the magnetic wall portion 25 extends along the gaps between the turn portions 101-108 of the coil element 10i when viewed in the axial direction. In the illustrated example, the magnetic wall portion 25 has a spiral shape and overlaps with the gaps between the turn portions 101-108 of the coil element 10i when viewed in the axial direction.

[0091] The magnetic wall portion 25 has magnetism. The magnetic wall portion 25 is provided to suppress loss due to eddy current and leakage magnetic flux. The magnetic wall portion 25 is also provided to increase the coupling coefficient with other coil units. The magnetic wall portion 25 may be made of the same material as the magnetic resin layer 20 described above. The magnetic wall portion 25 may be formed integrally with the magnetic resin layer 20.

[0092] The relative magnetic permeability of the magnetic wall 25 is preferably 2.0 or more, and may be 2.0 or more and 20.0 or less. The relative magnetic permeability of the magnetic wall 25 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 magnetic wall 25 is not particularly limited, but if it is too large, the flexibility and strength of the magnetic wall 25 may be undesirably impaired. Therefore, the relative magnetic permeability of the magnetic wall 25 may be 30 or less.

[0093] A protruding height 25H by which the magnetic wall portion 25 protrudes in the first stacking direction AD1 beyond the first main surface 10a of the coil 10 is not particularly limited, but may be, for example, 0.5 mm or more, or 1.0 mm or more.

[0094] (First shielding member) The first shield member 30 is provided to suppress magnetic transmission and / or leakage magnetic field. The first shield member 30 is provided between the second shield member 50 and the coil 10 and the magnetic resin layer 20. The first shield member 30 is formed in a plate shape and spreads along a plane perpendicular to the axial direction of the coil 10. The first shield member 30 has a size such that its outer periphery is located outside the magnetic resin layer 20 and the coil 10 when viewed in the axial direction. In the illustrated example, the first shield member 30 is rectangular when viewed in the axial direction.

[0095] The first shield member 30 includes a magnetic material. As described above, the magnetic field generated by the coil unit 5 spreads in all directions relative to the central axis C of the coil 10. At this time, the first shield member 30 has magnetism, so that the spreading magnetic flux lines can be directed toward the central axis C. The first shield member 30 is also provided to prevent the magnetic lines from reaching surrounding components. As a result, the first shield member 30 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0096] The first shielding member 30 preferably includes a soft magnetic material. More specifically, the first shielding member 30 includes a ferrite, preferably a soft ferrite. The first shielding member 30 may also include a nanocrystalline magnetic material.

[0097] In the example shown in FIG. 4, the first shield member 30 is disposed apart from the magnetic resin layer 20, but this is not limited thereto. The first shield member 30 may be in contact with the magnetic resin layer 20. When the first shield member 30 is disposed apart from the magnetic resin layer 20, a spacer (not shown) may be disposed between the first shield member 30 and the magnetic resin layer 20. This allows the distance between the first shield member 30 and the magnetic resin layer 20 to be maintained at a predetermined distance. The distance between the first shield member 30 and the magnetic resin layer 20 is not particularly limited, but is, for example, 3 mm or less. Note that the longer the distance between the first shield member 30 and the magnetic resin layer 20, the more difficult it is for heat to be dissipated from the coil unit 5, and there is a risk that the coil unit 5 will become hot. For this reason, the distance between the first shield member 30 and the magnetic resin layer 20 is preferably 1 mm or less. The distance between the first shield member 30 and the magnetic resin layer 20 may be 0 mm. In other words, the first shield member 30 and the magnetic resin layer 20 may be in direct contact or in close contact with each other. Reducing the distance between the first shield member 30 and the magnetic resin layer 20 is also preferable for reducing the dimensions of the coil unit 5 (particularly, the dimensions along the axial direction).

[0098] In the illustrated example, the first shield member 30 is divided into a plurality of shield pieces 30P. In other words, the first shield member 30 includes a plurality of shield pieces 30P arranged in the same plane. By forming the first shield member 30 from a plurality of shield pieces 30P, it is possible to easily manufacture a first shield member 30 having a size such that an outer edge is located outside the coil 10 as viewed in the axial direction. The dimensions of each shield piece 30P as viewed in the axial direction may be such that the shield piece 30P can be surrounded by a square outline of 150 mm x 150 mm.

[0099] In the illustrated example, the first shield member 30 includes first to eighth shield pieces 31 to 38. In the illustrated example, each of the shield pieces 31 to 38 includes ferrite. More specifically, each of the shield pieces 31 to 38 is formed of a ferrite plate.

[0100] Gaps 40 are formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31. The width of gap 40 is arbitrary, but considering the manufacturing tolerance of shield pieces 31 to 38, the width of gap 40 is preferably 1 mm or more. Furthermore, from the viewpoint of suppressing the transmission of magnetic lines through gap 40, the width of gap 40 is preferably 6 mm or less.

[0101] In the illustrated example, each of the shield pieces 31 to 38 is generally triangular. More specifically, each of the shield pieces 31 to 38 is generally right-angled triangular. The first to eighth gaps 41 to 48 formed between the adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31 extend radially from the central axis C. When viewed in the axial direction, the first to eighth gaps 41 to 48 cross at least a part of the first to eighth straight line groups 11G to 18G, respectively. In the illustrated example, when viewed in the axial direction, the first to eighth gaps 41 to 48 cross the first to eighth straight line groups 11G to 18G, respectively. In other words, when viewed in the axial direction, the first to eighth gaps 41 to 48 extend radially from the inner side to the outer side of the first to eighth straight portion groups 11G to 18G, respectively.

[0102] By arranging the shield pieces 31, 38 so that the first gap 41 crosses the first straight portion 11, the magnetic field lines formed around the first straight portion 11 are prevented from reaching the second shield member 50 through the first gap 41. This makes it possible to prevent eddy currents from being generated in the second shield member 50 by the magnetic field lines formed around the first straight portion 11. This means that it is possible to prevent an increase in loss in the coil unit 5 due to the presence of the first gap 41.

[0103] Similarly, the shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38 are arranged so that the second to eighth gaps 42-48 cross the second to eighth straight portions 12-18, respectively, thereby preventing the magnetic field lines formed around the second to eighth straight portions 12-18 from reaching the second shield member 50 through the second to eighth gaps 42-48. This makes it possible to prevent the magnetic field lines formed around the second to eighth straight portions 12-18 from generating eddy currents in the second shield member 50. This means that it is possible to prevent an increase in loss in the coil unit 5 due to the presence of the second to eighth gaps 42-48.

[0104] When viewed in the axial direction, the angle formed between the first gap 41 and the first straight portion 11 may be, for example, 80° to 100°. In this case, an increase in loss in the coil unit 5 due to the presence of the first gap 41 can be effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the first gap 41 can be effectively suppressed. Furthermore, as can be seen from FIG. 5, when viewed in the axial direction, the angle formed between the first gap 41 and the first straight portion 11 may be 90°. In this case, an increase in loss in the coil unit 5 due to the presence of the first gap 41 can be further effectively suppressed.

[0105] Similarly, the angles formed by the second to eighth gaps 42-48 and the second to eighth straight portions 12-18 as viewed in the axial direction may be, for example, 80° to 100°, respectively. In this case, the increase in loss of the coil unit 5 due to the presence of the second to eighth gaps 42-48 can be effectively suppressed. Furthermore, as can be seen from FIG. 5, the angles formed by the second to eighth gaps 42-48 and the second to eighth straight portions 12-18 as viewed in the axial direction may be 90°. In this case, the increase in loss of the coil unit 5 due to the presence of the second to eighth gaps 42-48 can be more effectively suppressed. Note that, when the gap 40 intersects with the curved portion of the turn portions 101-108 as viewed in the axial direction, the angle formed by the gap 40 and the tangent of the curved portion at the intersection of the gap 40 and the turn portions 101-108 as viewed in the axial direction is preferably 80° to 100°, more preferably 90°. In this case as well, an increase in loss in the coil unit 5 due to the presence of the gap 40 can be effectively suppressed.

[0106] As described above, when the magnetic resin layer 20 includes a plurality of magnetic resin elements, each magnetic resin element may have the same size and shape as the shield pieces overlapping in the axial direction. In this case, the gaps extending between adjacent magnetic resin elements may coincide with the gaps 41-48 extending between the shield pieces 31-38 when viewed in the axial direction.

[0107] (Second shielding member) The second shield member 50 is disposed on the second side of the coil 10. The second shield member 50 shields the electromagnetic waves emitted by the coil 10 from the second side. The electromagnetic waves emitted by the coil unit 5 are blocked by the second shield member 50, so that the electromagnetic waves can be prevented from affecting other electronic components, the human body, and the like. The second shield member 50 can be formed of a metal such as aluminum.

[0108] As shown in FIG. 4, the second shield member 50 is disposed at a distance from the first shield member 30. A spacer 55 may be disposed between the second shield member 50 and the first shield member 30. This allows the distance between the second shield member 50 and the first shield member 30 to be maintained at a predetermined distance. The spacer 55 is not particularly limited as long as it is an insulating material, but is preferably a thermally conductive material. This allows the spacer 55 to promote heat dissipation from the coil unit 5. The first shield member 30 and the second shield member 50 may be connected via a thermally conductive material serving as the spacer 55.

[0109] The thermally conductive member as the spacer 55 can be formed, for example, from an insulating heat dissipation material prepared by dispersing a material with high thermal conductivity in an insulating resin. In addition, when high thermal conductivity is required for the spacer 55, the spacer 55 may be prepared using the insulating heat dissipation material and a metal member. For example, a metal block made of a metal such as aluminum is sandwiched between a film made of the insulating heat dissipation material, thereby making it possible to prepare a spacer 55 having high thermal conductivity. The spacer 55 thus prepared is disposed between the first shielding member 30 and the second shielding member 50 so that the film is positioned between the first shielding member 30 and the metal block and between the second shielding member 50 and the metal block, thereby effectively promoting heat dissipation from the coil unit 5 while ensuring insulation between the first shielding member 30 and the second shielding member 50.

[0110] Here, when the second shield member 50 is disposed close to the first shield member 30, for example, when the distance between the second shield member 50 and the first shield member 30 is set to 10 mm or less, it is considered that the magnetic field lines generated in the coil 10 are likely to reach the second shield member 50, and thus eddy currents are likely to be generated in the second shield member 50. When eddy currents are likely to be generated in the second shield member 50, the loss of the second shield member 50 increases, and the loss of the coil unit 5 increases. In particular, in the coil unit 5 of this embodiment, a gap 40 is formed in the first shield member 30. Therefore, it is considered that the magnetic field lines reach the second shield member 50 through the gap 40 in the first shield member 30. Therefore, when the second shield member 50 is disposed close to the first shield member 30 in the coil unit 5 of this embodiment, it is considered that the loss of the coil unit 5 is larger than that of a coil unit in which the gap 40 is not formed in the first shield member 30.

[0111] However, according to the findings of the present inventors, by including the magnetic resin layer 20 in direct contact (or in close contact) with the second main surface 10b of the coil 10 in the coil unit 5, it is possible to suppress an increase in loss in the coil unit 5 caused by bringing the second shield member 50 closer to the first shield member 30. Furthermore, according to the findings of the present inventors, by setting the positional relationship between the coil 10 and the gaps 41-48 between the shield pieces 31-38 as described above, it is possible to suppress an increase in loss in the coil unit 5 caused by bringing the second shield member 50 closer to the first shield member 30. This contributes to reducing the dimensions of the coil unit 5 (particularly the dimensions along the axial direction).

[0112] When the coil unit 5 is mounted on an automobile, the space available for installation is limited. For this reason, it is advantageous to reduce the dimensions of the coil unit 5. Therefore, in this embodiment, when the coil unit 5 is a power receiving coil unit installed in an automobile, the distance between the second shield member 50 and the first shield member 30 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 unit 5 is a power transmitting coil unit installed on a road or a parking lot, the distance between the second shield member 50 and the first shield member 30 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 50 and the first shield member 30, the more difficult it is for heat to be dissipated from the coil unit 5, and the higher the temperature of the coil unit 5 may be. For this reason, even when the coil unit 5 is installed on a road or a parking lot, the distance between the second shield member 50 and the first shield member 30 is preferably 1 mm or less. Furthermore, when the distance between the second shield member 50 and the first shield member 30 is 1 mm or more, it is preferable to use, as the spacer 55, the above-mentioned spacer having high thermal conductivity.

[0113] (Connection terminal) 3, the first connection terminal 56 is connected to the first straight portion 11 of the first turn portion 101 that forms the innermost periphery of the coil element 10i. The second connection terminal 57 is connected to the eighth straight portion 18 of the eighth turn portion 108 that forms the outermost periphery of the coil element 10i. The first connection terminal 56 and the second connection terminal 57 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A.

[0114] When the coil unit 5 is used as the power transmission coil unit, the first connection terminal 56 and the second connection terminal 57 are connected to the high frequency current supply unit 1A or the AC power supply as shown in Fig. 1. When a high frequency current is supplied to the coil unit 5, the current can be passed from the first connection terminal 56 to the coil 10, and then from the second connection terminal 57 to the high frequency current supply unit 1A or the AC power supply. Also, the current can be passed from the second connection terminal 57 to the coil 10, and then from the first connection terminal 56 to the high frequency current supply unit 1A or the AC power supply. This makes it possible to generate a magnetic field including magnetic lines of force along the central axis of the coil 10.

[0115] On the other hand, when the coil unit 5 is used as the power receiving coil unit, a high frequency current can be generated in the coil 10 by receiving a magnetic field including magnetic field lines along the central axis of the coil 10. Then, this high frequency current can be supplied to an external device from the first connection terminal 56 or the second connection terminal 57.

[0116] In the example shown in FIG. 5, the first connection terminal 56 is connected to the inner end 10e1 of the coil 10 on the side of the second main surface 10b of the coil 10, but is not limited thereto. The first connection terminal 56 may be connected to the inner end 10e1 of the coil 10 on the side of the first main surface 10a of the coil 10. The first connection terminal 56 extends from the inside to the outside of the coil 10 as viewed in the axial direction. In this example, as can be seen from FIG. 4, the connection terminal 56 is connected to the coil 10 via a conductive connection portion 58. The connection terminal 56 is spaced from the second to eighth turn portions 102 to 108 of the coil 10 in the axial direction and extends from the inside to the outside of the coil 10.

[0117] As shown in Fig. 5, the first connection terminal 56 may extend within a gap 40 extending from the inside to the outside of the coil 10 when viewed in the axial direction. Also, as shown in Fig. 4, the first connection terminal 56 may extend from the inside to the outside of the coil 10 at a height position where it overlaps with the shield piece 30P when viewed from the side of the coil unit 5. According to the knowledge obtained by the present inventors, this makes it possible to suppress loss in the first shield member 30.

[0118] The first connection terminal 56 and the connection portion 58, the connection portion 58 and the coil 10, and the second connection terminal 57 and the coil 10 are connected by ultrasonic bonding. However, the connection method is not limited, and for example, a conductive adhesive may be used for connection.

[0119] (Inner frame) As shown in Fig. 2, the inner frame 60 circumferentially extends inside the coil 10. As can be seen from Fig. 4, the inner frame 60 protrudes in the first stacking direction AD1 beyond the first main surface 10a of the coil 10. The inner frame 60 is located on the first side of the first shielding member 30, in other words, on the coil 10 side relative to the first shielding member 30.

[0120] The inner frame 60 is magnetic. The inner frame 60 is provided to suppress loss due to eddy current (so-called Joule loss) and leakage magnetic flux. The inner frame 60 is also provided to increase the coupling coefficient with other coil units. Here, Joule loss refers to loss caused by the current of the coil 10 or the second shield member 50.

[0121] In the present embodiment, the inner frame 60 preferably includes a soft magnetic material. More specifically, the inner frame 60 includes a ferrite, preferably a soft ferrite. The inner frame 60 may also include a nanocrystalline magnetic material.

[0122] The relative magnetic permeability of the inner frame 60 is not particularly limited, but is preferably 100 or more, and may be 100 or more and 10,000 or less. The relative magnetic permeability of the inner frame 60 may be 500 or more, 1,000 or more, 2,000 or more, or 2,500 or more. The relative magnetic permeability of the inner frame 60 may be 8,000 or less, 6,000 or less, 4,000 or less, or 3,500 or less.

[0123] 4, the lower end of the inner frame 60 is embedded in the magnetic substance resin layer 20. A recess 23 for accommodating the inner frame 60 is provided on the surface of the magnetic substance resin layer 20 facing the first side. Of course, the inner frame 60 may be disposed on the surface of the magnetic substance resin layer 20 facing the first side.

[0124] A protruding height 60H of the inner frame 60 protruding from the first main surface 10a in the first stacking direction AD1 is not particularly limited, but may be, for example, 0.5 mm or more, 1.0 mm or more, 2.0 mm or more, or 3.0 mm or more. A width 60W of the inner frame 60 is not particularly limited, but may be, for example, 3 mm or more, or 5 mm or more. A width 60W of the inner frame 60 may be 10 mm or less.

[0125] In the illustrated example, the inner frame 60 has a polygonal shape as a whole, corresponding to the polygonal shape of the coil 10 as a whole. The inner frame 60 includes a plurality of rod-shaped inner frame elements 61-69. Each of the inner frame elements 61-69 extends linearly along the linear portions 11-18 of the coil element 10i.

[0126] In the illustrated example, the inner frame 60 has an octagonal shape as a whole, corresponding to the coil 10 having an octagonal shape as a whole. The inner frame 60 includes first to ninth inner frame elements 61 to 69. The first to eighth inner frame elements 61 to 68 extend linearly along the first to eighth straight portions 11 to 18 of the first turn portion 101 of the coil element 10i, respectively. The ninth inner frame element 69 extends linearly along the first straight portion 11 of the second turn portion 102 of the coil element 10i. In the illustrated example, the ninth inner frame element 69 extends between the eighth inner frame element 68 and the first connection terminal 56 when viewed in the axial direction. The ninth inner frame element 69 does not overlap the first connection terminal 56 when viewed in the axial direction.

[0127] The distance 60L between the coil 10 and the inner frame 60 is preferably 3 mm or less, may be 2 mm or less, may be 1 mm or less, or may be 0.5 mm or less. More specifically, the distance 60L between the first to eighth straight portions 11 to 18 of the first turn portion 101 and the first to eighth inner frame elements 61 to 68 is preferably 3 mm or less, may be 2 mm or less, or may be 1 mm or less. The distance 60L between the first straight portion 11 of the second turn portion 102 and the ninth inner frame element 69 is preferably 3 mm or less, may be 2 mm or less, or may be 1 mm or less. The distance 60L may be 0 mm. That is, the coil 10 and the inner frame 60 may be in direct contact with each other. Therefore, the distance 60L may be 0 mm or more and 3 mm or less.

[0128] The inner frame elements 61-69 may be separated from each other. In this case, the distance between the circumferentially adjacent ends of the inner frame elements 61-69 is preferably 0.5 mm or less, more preferably 0.3 mm or less. In this case, leakage of magnetic flux from between the circumferentially adjacent inner frame elements 61,62; 62,63; 63,64; 64,65; 65,66; 66,67; 67,68; 68,69 is suppressed. The distance between the circumferentially adjacent ends of the inner frame elements 61-69 may be 0 mm. That is, the circumferentially adjacent inner frame elements 61,62; 62,63; 63,64; 64,65; 65,66; 66,67; 67,68; 68,69 may be in direct contact with each other. Of course, the inner frame elements 61-69 may be integrally formed.

[0129] (Outer frame) As shown in Fig. 2, the outer frame 70 extends circumferentially outside the coil 10. As can be seen from Fig. 4, the outer frame 70 protrudes in the first stacking direction AD1 beyond the first main surface 10a of the coil 10. Furthermore, when viewed in the axial direction, the outer frame 70 is located inside the outer edge 30e of the first shielding member 30. The outer frame 70 is located on the first side of the first shielding member 30, in other words, on the coil 10 side of the first shielding member 30.

[0130] The outer frame 70 has magnetic properties. The outer frame 70 is provided to suppress loss due to eddy current (so-called Joule loss) and leakage magnetic flux. The outer frame 70 is also provided to increase the coupling coefficient with other coil units.

[0131] The outer frame 70 in this embodiment preferably includes a soft magnetic material. More specifically, the outer frame 70 includes ferrite, preferably soft ferrite. The outer frame 70 may also include a nanocrystalline magnetic material.

[0132] The relative magnetic permeability of the outer frame 70 is not particularly limited, but is preferably 100 or more, and may be 100 or more and 10,000 or less. The relative magnetic permeability of the outer frame 70 may be 1,000 or more, 2,000 or more, or 3,000 or more. The relative magnetic permeability of the outer frame 70 may be 8,000 or less, 6,000 or less, or 4,000 or less.

[0133] 4, the lower end of the outer frame 70 is embedded in the magnetic substance-resin layer 20. A recess 24 for accommodating the outer frame 70 is provided on the surface of the magnetic substance-resin layer 20 facing the first side. Of course, the outer frame 70 may be disposed on the surface of the magnetic substance-resin layer 20 facing the first side.

[0134] A protruding height 70H of the outer frame 70 protruding from the first main surface 10a in the first stacking direction AD1 is not particularly limited, but may be, for example, 0.5 mm or more, 1.0 mm or more, 2.0 mm or more, or 3.0 mm or more. A width 70W of the outer frame 70 is not particularly limited, but may be, for example, 3 mm or more, or 5 mm or more. A width 70W of the outer frame 70 may be 10 mm or less.

[0135] In the illustrated example, the outer frame 70 has a polygonal shape as a whole corresponding to the polygonal shape of the coil 10. The outer frame 70 includes a plurality of rod-shaped outer frame elements 71-79. Each of the outer frame elements 71-79 extends linearly along the linear portions 11-18 of the coil elements 10i.

[0136] In the illustrated example, the outer frame 70 has an octagonal shape as a whole, corresponding to the coil 10 having an octagonal shape as a whole. The outer frame 70 includes first to ninth outer frame elements 71 to 79. The first to eighth outer frame elements 71 to 78 extend linearly along the first to eighth straight portions 11 to 18 of the eighth turn portion 108 of the coil element 10i, respectively. The ninth outer frame element 79 extends linearly along the eighth straight portion 18 of the seventh turn portion 107 of the coil element 10i. In the illustrated example, the ninth outer frame element 79 extends between the first outer frame element 71 and the second connection terminal 57 when viewed in the axial direction. The ninth outer frame element 79 does not overlap the second connection terminal 57 when viewed in the axial direction.

[0137] The distance 70L between the coil 10 and the outer frame 70 is preferably 3 mm or less, may be 2 mm or less, may be 1 mm or less, or may be 0.5 mm or less. More specifically, the distance between the first straight portion 11 of the eighth turn portion 108 and the first outer frame element 71 is preferably 3 mm or less, may be 2 mm or less, or may be 1 mm or less. Similarly, the distance between the second to eighth straight portions 12 to 18 of the eighth turn portion 108 and the second to eighth outer frame elements 72 to 78 is preferably 3 mm or less, may be 2 mm or less, or may be 1 mm or less. Also, the distance between the eighth straight portion 18 of the seventh turn portion 107 and the ninth outer frame element 79 is preferably 3 mm or less, may be 2 mm or less, or may be 1 mm or less. The distance 70L may be 0 mm. That is, the coil 10 and the outer frame 70 may be in direct contact with each other. Therefore, the distance 70L may be 0 mm or more and 3 mm or less.

[0138] As shown in FIG. 5, the eighth outer frame element 78 and the ninth outer frame element 79 are spaced apart from each other. The second connection terminal 57 passes between the eighth outer frame element 78 and the ninth outer frame element 79 and extends from the inside to the outside of the outer frame 70. The other outer frame elements 71-78 may also be separated from each other. The outer frame elements 71 and 79 may also be separated from each other. In this case, the distance between the circumferentially adjacent ends of the outer frame elements 71-78 and the distance between the circumferentially adjacent ends of the outer elements 79,71 is preferably 0.5 mm or less, more preferably 0.3 mm or less. In this case, leakage of magnetic flux from between the circumferentially adjacent outer frame elements 71,72; 72,73; 73,74; 74,75; 75,76; 76,77; 77,78; 79,71 is suppressed. The distance between the circumferentially adjacent ends of the outer frame elements 71-78 and the distance between the circumferentially adjacent ends of the outer elements 79, 71 may be 0 mm. That is, the circumferentially adjacent outer frame elements 71, 72; 72, 73; 73, 74; 74, 75; 75, 76; 76, 77; 77, 78; 79, 71 may be in direct contact with each other. Of course, the multiple outer frame elements 71-79 may be formed integrally.

[0139] In the illustrated example, the outer frame 70 further has tenth and eleventh outer frame elements 80, 81. The tenth and eleventh outer frame elements 80, 81 extend along the second connection terminal 57 on both sides of the second connection terminal 57 when viewed in the axial direction.

[0140] One end of the tenth outer frame element 80 is disposed in the vicinity of the eighth outer frame element 78. The distance between the one end of the tenth outer frame element 80 and the eighth outer frame element 78 is preferably 0.5 mm or less, and more preferably 0.3 mm or less. In this case, leakage of magnetic flux from between the tenth outer frame element 80 and the eighth outer frame element 78 is suppressed. The distance between the one end of the tenth outer frame element 80 and the eighth outer frame element 78 may be 0 mm. Of course, the tenth outer frame element 80 may be formed integrally with the multiple outer frame elements 71 to 79.

[0141] One end of the eleventh outer frame element 81 is disposed in the vicinity of the ninth outer frame element 79. The distance between one end of the eleventh outer frame element 81 and the ninth outer frame element 79 is preferably 0.5 mm or less, and more preferably 0.3 mm or less. In this case, leakage of magnetic flux from between the eleventh outer frame element 81 and the ninth outer frame element 79 is suppressed. The distance between the one end of the eleventh outer frame element 81 and the ninth outer frame element 79 may be 0 mm. Of course, the eleventh outer frame element 81 may be formed integrally with the multiple outer frame elements 71 to 79.

[0142] In the illustrated example, as shown in FIG. 6, the first outer frame element 71 includes a discontinuous portion 85. The discontinuous portion 85 is formed between both ends of the first outer frame element 71. More specifically, the first outer frame element 71 includes a first portion 71a and a second portion 71b aligned along the first direction D1 of the first outer frame element 71. One end 71aa of the first portion 71a forms one end of the first outer frame element 71. The other end 71ab of the first portion 71a faces one end 71ba of the second portion 71b in the first direction D1. The other end 71bb of the second portion 71b forms the other end of the first outer frame element 71. The discontinuous portion 85 is formed between the other end 71ab of the first portion 71a and one end 71ba of the second portion 71b. The discontinuous portion 85 overlaps the first connection terminal 56 when viewed in the axial direction.

[0143] According to the findings of the present inventors, in a coil unit 5 in which the first connection terminal 56 is connected to the inner end 10e1 of the coil 10, a discontinuous portion 85 that overlaps with the first connection terminal 56 as viewed in the axial direction is formed in the outer frame 70, thereby making it possible to effectively suppress losses in the coil unit 5 (particularly, iron loss of the first shield member 30). In particular, it is possible to effectively suppress iron loss of the shield piece 31 that overlaps with the inner end region of the coil element 10i (in the illustrated example, the first straight portion 11 of the first turn portion 101) as viewed in the axial direction.

[0144] In the example shown in FIG. 6, the width 85W of the discontinuous portion 85 is larger than the width of the first connection terminal 56, but is not limited thereto. As shown in FIG. 7, the width 85W of the discontinuous portion 85 may be smaller than the width of the first connection terminal 56. The width 85W of the discontinuous portion 85 is preferably 0.8 mm or more, and more preferably 1 mm or more. The width 85W of the discontinuous portion 85 may be 2 mm or more, 5 mm or more, 10 mm or more, 20 mm or more, 30 mm or more, or 40 mm or more. If the width 85W of the discontinuous portion 85 is 5 mm or more, the risk of the width 85W of the discontinuous portion 85 becoming less than 0.8 mm is suppressed even if the coil unit 5 is subjected to vibration or impact and the first portion 71a and the second portion 71b of the first outer frame element 71 move. It should be noted that the width 85W of the discontinuous portion 85 is the distance between the ends 71ab and 71ba of the outer frame 70 that face each other with the discontinuous portion 85 therebetween.

[0145] Furthermore, as shown in FIG. 6, when the discontinuous portion 85 overlaps with the first connecting terminal 56 when viewed in the axial direction and the width 85W of the discontinuous portion 85 is greater than the width of the first connecting terminal 56, in order to prevent excessive leakage of the magnetic field, the distances 71La, 71Lb between the ends 71ab, 71ba of the outer frame 70 forming the discontinuous portion 85 and the first connecting terminal 56 are preferably 10 mm or less, and more preferably 5 mm or less.

[0146] <Modification> It should be noted that various modifications can be made to the above-described embodiment. In the modifications described below, the same or similar reference numerals are used to designate the same parts as those of the coil unit 5 described above, and detailed descriptions thereof will be omitted.

[0147] 2 to 7, the coil unit 5 has an inner frame 60 and an outer frame 70, but is not limited to this. The coil unit 5 may have only one of the inner frame 60 and the outer frame 70. In this case as well, losses in the coil unit 5 (especially Joule losses) can be suppressed.

[0148] In the illustrated example, the inner frame 60 is formed in a circumferential shape, but is not limited to this. The inner frame 60 may be in the shape of a plate or block that extends continuously in the inner region of the coil 10 when viewed in the axial direction. When viewed in the axial direction, the inner frame 60 may extend continuously from the vicinity of the first turn portion 11 of the coil 10 to the central axis C. The central axis C may pass through the inner frame 60.

[0149] 2 to 7, the discontinuous portion 85 overlaps with the first connection terminal 56 when viewed in the axial direction, but this is not limited to this. As shown in Fig. 8, the discontinuous portion 85 does not have to overlap with the first connection terminal 56 when viewed in the axial direction. In this case as well, losses (particularly iron loss) in the coil unit 5 can be suppressed.

[0150] Furthermore, according to the knowledge of the present inventors, the discontinuous portion 85 may overlap the gap 40 between the shield pieces 30P when viewed in the axial direction. In this case, the discontinuous portion 85 does not have to overlap the first connection terminal 56 when viewed in the axial direction. In this case as well, losses (especially iron loss) in the coil unit 5 can be effectively suppressed.

[0151] 2 to 8, the outer frame 70 has the discontinuous portion 85, but this is not limited to this. The outer frame 70 does not have to have the discontinuous portion 85. In this case as well, losses (especially Joule losses) in the coil unit 5 can be suppressed.

[0152] 2 to 8, the first shielding member 30 is divided into a plurality of shielding pieces 30P, but is not limited to this. The first shielding member 30 does not have to be divided into a plurality of shielding pieces 30P.

[0153] In addition, the manner of division of the first shield member 30 is not limited to the manner shown in Fig. 2 to Fig. 6. For example, in the examples shown in Fig. 2 to Fig. 6, the multiple shield pieces 30P are approximately the same size, but as shown in Fig. 9, the multiple shield pieces 30P may be different in size from each other. According to the knowledge obtained by the inventor, when the direction in which the coil element 10i turns around the central axis C from the inner end 10e1 to the outer end 10e2 is defined as the first winding direction CD1, the larger the area of ​​the shield piece 31 adjacent to the first connection terminal 56 in the first winding direction CD1, the smaller the iron loss of the shield piece 31 can be, and the smaller the iron loss of the entire first shield member 30 can be. In other words, from the viewpoint of suppressing the iron loss of the first shield member 30, it is not preferable to make the shield piece 31 adjacent to the first connection terminal 56 in the first winding direction CD1 small. Therefore, the area of ​​the shield piece 31 adjacent to the first connection terminal 56 in the first winding direction CD1 is preferably equal to or larger than the area of ​​the shield piece 38 adjacent to the shield piece 31 across the first connection terminal 56. In addition, the area of ​​the shield piece 31 adjacent to the first connection terminal 56 in the first winding direction CD1 is preferably equal to or larger than the area of ​​the shield piece 32 adjacent to the shield piece 31 in the first winding direction CD1.

[0154] 2 to 6, the coil 10 has a regular octagonal shape overall to improve the performance of the coil unit 5, but this is not limited thereto. According to the findings of the inventors, when the coil 10 has a dodecagonal shape overall, the performance of the coil unit 5 can be improved by making the shape of the coil 10 closer to a regular dodecagon. Therefore, the coil 10 may have a regular dodecagonal shape overall. In this case, the coil element 10i (the conductor 10E) may be wound so that the turn portions 101 to 108 form a regular dodecagon.

[0155] 2 to 6, the first shield member 30 is divided into a plurality of shield pieces 30P, and the first connection terminal 56 extends within the gap 40 between adjacent shield pieces 30P when viewed in the axial direction, but this is not limited to this. A notch extending from the inside to the outside of the coil 10 when viewed in the axial direction may be formed in the first shield member 30, and the first connection terminal 56 may extend within this notch. In this case, too, the first connection terminal 56 may extend from the inside to the outside of the coil 10 at a height position where it overlaps with the first shield member 30 when viewed from the side of the coil unit 5.

[0156] 2 to 9, the coil 10 includes a single coil element 10i, but is not limited to this. As shown in Fig. 10 to 13, the coil 10 may have multiple coil elements 10j, 10jj. In this case, too, the coil unit 5 includes an inner frame 60 and / or an outer frame 70, thereby making it possible to suppress losses (particularly Joule losses) in the coil unit 5.

[0157] Hereinafter, a coil unit 5 including a coil 10 including a plurality of coil elements 10j, 10jj will be described with reference to Figs. 10 to 13. Fig. 10 is a perspective view of the coil unit 5 according to this modification. Fig. 11 is an exploded perspective view of the coil unit 5 shown in Fig. 10. Fig. 12 is a cross-sectional view of the coil unit 5 taken along line XII-XII in Fig. 10. Fig. 13 is a plan view of the coil unit 5. The magnetic resin layer 20 is omitted from Figs. 11 and 13. Also, the magnetic wall portion 25 is omitted from Fig. 13.

[0158] 10 to 13, the coil 10 includes a first coil element 10j and a second coil element 10jj arranged in the axial direction. The second coil element 10jj and the first coil element 10j are arranged in this order in a first stacking direction AD1. The pitch of the first coil element 10j and the second coil element 10jj along the axial direction is, for example, 5 mm or more and 40 mm or less.

[0159] In the illustrated example, each of the coil elements 10j, 10jj includes a conductor 10E having a spiral shape. The conductor 10E includes a plurality of turn portions 101-105 aligned in the radial direction. In the illustrated example, the conductor 10E includes first to fifth turn portions 101-105. The first to fifth turn portions 101-105 are aligned in this order from the inner side to the outer side in the radial direction.

[0160] As can be seen from FIGS. 12 and 13, the first to fifth turn portions 101 to 105 of the first coil element 10j are aligned in the axial direction with the first to fifth turn portions 101 to 105 of the second coil element 10jj, respectively.

[0161] Each turn portion 101-105 of each coil element 10j, 10jj includes a plurality of straight portions 11-17 arranged around the central axis C. The straight portions 11-17 adjacent to each other in the circumferential direction of a circle centered on the central axis C are connected to each other. The first to fourth turn portions 101-104 of each coil element 10j, 10jj include turn connection portions 19. The first to fourth turn portions 101-104 are connected to the second to fifth turn portions 102-105 at the turn connection portions 19, respectively.

[0162] 13, the turn connection portions 19 of the first to fourth turn portions 101 to 104 form a turn connection portion group 19G. The turn connection portion group 19G extends in a fourth direction D4 as a whole. The turn connection portion group 19G is disposed such that the central axis C passes between the turn connection portion group 19G and the fourth straight portion group 14G.

[0163] As can be seen from Fig. 13, the first to seventh straight portions 11 to 17 and the turn connection portion 19 of the first turn portion 101 of the first coil element 10j are aligned in the axial direction with the first to seventh straight portions 11 to 17 and the turn connection portion 19 of the first turn portion 101 of the second coil element 10jj, respectively. Similarly, the first to seventh straight portions 11 to 17 and the turn connection portion 19 of the second to fourth turn portions 102 to 104 of the first coil element 10j are aligned in the axial direction with the first to seventh straight portions 11 to 17 and the turn connection portion 19 of the second to fourth turn portions 102 to 104 of the second coil element 10jj, respectively. In addition, the first to seventh straight portions 11 to 17 of the fifth turn portion 105 of the first coil element 10j are aligned in the axial direction with the first to seventh straight portions 11 to 17 of the fifth turn portion 105 of the second coil element 10jj, respectively.

[0164] As can be seen from Fig. 12, the first turn portion 101 of the first coil element 10j and the first turn portion 101 of the second coil element 10jj are electrically connected. In the illustrated example, the first coil element 10j and the second coil element 10jj are connected via a conductive connection portion 59. A first connection terminal 56 is connected to the first straight portion 11 of the fifth turn portion 105 of the second coil element 10jj. A second connection terminal 57 is connected to the seventh straight portion 17 of the fifth turn portion 105 of the first coil element 10j.

[0165] As shown in FIG. 12, the first coil element 10j forms the first main surface 10a of the coil 10. The second coil element 10jj forms the second main surface 10b of the coil 10. The magnetic body resin layer 20 is in close contact with the second main surface 10b of the coil 10. In the example shown in FIG. 12, the coil 10 is embedded in the magnetic body resin layer 20. In the example shown in FIG. 12, the magnetic body resin layer 20 is also in close contact with the surface of the first coil element 10j facing the second side. However, this is not limited thereto, and the magnetic body resin layer 20 does not have to be in close contact with the surface of the first coil element 10j facing the second side.

[0166] 10 to 13, the inner frame 60 includes first to eighth inner frame elements 61 to 68. The first to seventh inner frame elements 61 to 67 extend linearly along the first to seventh straight portions 11 to 17 of the first turn portion 101 of the first coil element 10j, respectively. The eighth inner frame element 68 extends along the turn connection portion 19 of the first turn portion 101 of the first coil element 10j.

[0167] In the example shown in Figs. 10 to 13, the outer frame 70 includes first to eighth outer frame elements 71 to 78. The first to seventh outer frame elements 71 to 77 extend linearly along the first to seventh straight portions 11 to 17 of the fifth turn portion 105 of the coil element 10j, respectively. The eighth outer frame element 78 is disposed adjacent to the turn connection portion 19 of the fourth turn portion 104 of the first coil element 10j. The eighth outer frame element 78 extends linearly along the fourth direction D4. In the illustrated example, the eighth outer frame element 78 extends between the first outer frame element 71 and the seventh outer frame element 77 when viewed in the axial direction.

[0168] The eighth outer frame element 78 includes two discontinuous parts 85, 86. The discontinuous parts 85, 86 are formed between both ends of the eighth outer frame element 78. More specifically, the eighth outer frame element 78 includes first to third parts 78a to 78c aligned along the fourth direction D4. One end of the first part 78a forms one end of the eighth outer frame element 78. The other end of the first part 78a faces one end of the second part 78b in the fourth direction D4. The other end of the second part 78b faces one end of the third part 78c in the fourth direction D4. The other end of the third part 78c forms the other end of the eighth outer frame element 78. A discontinuous part 85 is formed between the other end of the first part 78a and one end of the second part 78b. When viewed in the axial direction, the discontinuous portion 85 overlaps with the first connection terminal 56. A discontinuous portion 86 is formed between the other end of the second portion 78b and one end of the third portion 78c. The second connection terminal 57 extends from the inside to the outside of the outer frame 70 through the discontinuous portion 86.

[0169] 10 to 13, the outer frame 70 also has discontinuous parts 85, 86. This makes it possible to suppress losses (particularly iron loss) in the coil unit 5. Furthermore, the discontinuous part 85 overlaps with the first connection terminal 56. This makes it possible to effectively suppress losses (particularly iron loss) in the coil unit 5.

[0170] <Coil unit applications> The coil unit 5 according to this embodiment can be used as a power transmitting coil in the power transmitting device 1 of the wireless power transmission system S described above, and can be used as a power receiving coil in the power receiving device 2.

[0171] When the coil unit 5 is used as a power transmission coil, the first connection terminal 56 and the second connection terminal 57 are connected to the high frequency current supply unit 1A or the AC power supply as shown in Fig. 1. When a high frequency current is supplied to the coil unit 5, the current can be passed from the first connection terminal 56 to the coil 10, and then from the second connection terminal 57 to the high frequency current supply unit 1A or the AC power supply. Also, the current can be passed from the second connection terminal 57 to the coil 10, and then from the first connection terminal 56 to the high frequency current supply unit 1A or the AC power supply. This makes it possible to generate a magnetic field including magnetic lines of force along the central axis C of the coil 10.

[0172] On the other hand, when the coil unit 5 is used as a receiving coil, a high-frequency current can be generated in the coil 10 by receiving or generating a magnetic field including magnetic lines of force that pass through the inside of the coil 10. Then, this high-frequency current can be supplied to an external device from the first connection terminal 56 or the second connection terminal 57.

[0173] The coil unit 5 can also be used in a transformer, an antenna, etc. For example, when the coil unit 5 functions as a primary coil in a transformer, the first connection terminal 56 and the second connection terminal 57 are connected to an AC power source. When a high-frequency current is supplied, a magnetic flux can be supplied from the center of the coil 10 to the iron core.

[0174] <Coil unit 5 performance evaluation simulation 1> The following describes simulations performed to evaluate the performance of the coil units according to Examples 1-1 to 1-5 and Comparative Example 1. The simulations were performed using Femtet (registered trademark) manufactured by Murata Software Corporation.

[0175] The common conditions for the simulations of Examples 1-1 to 1-5 and Comparative Example 1 are as follows. The coil unit 5 includes a coil 10 formed in a spiral shape, similar to the example shown in Figures 2 to 6, a magnetic resin layer 20, a magnetic wall portion 25, a first shielding member 30, a second shielding member 50, a first connecting terminal 56, and a second connecting terminal 57. The coil 10 has a single coil element 10i. The coil element 10i is wound in a generally regular octagonal shape. The coil element 10i has first to eighth turn portions 101 to . In the second to eighth turn portions 102 to 108, the distance between adjacent turn portions 102, 103;...; 107, 108 is 6 mm. The distance between the first straight portion 11 of the first turn portion 101 and the first straight portion 11 of the second turn portion 102 is 3 mm. The coil element 10i is made of copper. The coil element 10i has a line width of 6 mm and a thickness of 0.5 mm. The dimensions of the coil 10 along the first direction D1 and the third direction D3 perpendicular to the first direction D1 are 295 mm and 295 mm, respectively. The magnetic resin layer 20 is in close contact with the second main surface 10b of the coil 10. The magnetic resin layer 20 has a relative magnetic permeability of 10. The magnetic wall portion 25 has a relative magnetic permeability of 10. The dimension of the gap between the coil 10 and the first shield member 30 is 1.0 mm. The relative magnetic permeability of the first shield member 30 is 3,000. The first shield member 30 is divided into eight shield pieces 31-38. Each of the shield pieces 31 to 38 is formed of a ferrite plate. Gaps 41 to 48 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31 extend radially from the central axis C. The first to eighth gaps 41 to 48 are perpendicular to the first to eighth straight line portions 11 to 18, respectively, when viewed in the axial direction. The width of the first to eighth gaps 41 to 48 is 5 mm. The dimensions of the first shield member 30 in the first direction D1 and the third direction D3 are 300 mm and 300 mm, respectively. The distance between the magnetic resin layer 20 and the first shield member 30 is 1 mm. The second shield member 50 is made of aluminum. The dimensions of the second shield member 50 in the first direction D1 and the third direction D3 are 320 mm and 320 mm, respectively. The distance between the first shielding member 30 and the second shielding member 50 is 1 mm. The first connection terminal 56 is connected to the inner end 10e1 of the coil 10 and extends from the inside to the outside of the coil 10. When viewed in the axial direction, the first connection terminal 56 traverses the first straight portion group 11G. When viewed in the axial direction, the first connection terminal 56 extends within the first gap 41. The high frequency current supplied is 40A and the frequency is 85KHz.

[0176] The common conditions for the simulations in Examples 1-1 to 1-5 are as follows.

[0177] The coil unit 5 has an inner frame 60 and an outer frame 70 similar to the examples shown in FIGS. The relative permeability of the inner frame 60 is 3000. The inner frame 60 includes first to ninth inner frame elements 61-69. Each of the inner frame elements 61 to 69 is formed from a ferrite rod. The width 60W of the inner frame 60 is 3 mm, and the protruding height 60H is 3 mm. When viewed in the axial direction, the distances between the first to eighth inner frame elements 61-68 and the first to eighth straight portions 11-18 of the first turn portion 101 are each 0.5 mm. When viewed in the axial direction, the distance between the ninth inner frame element 69 and the first straight portion 11 of the second turn portion 102 is 0.5 mm. The distance between adjacent inner frame elements 61 to 69 in the circumferential direction is 0.5 mm. The relative permeability of the outer frame 70 is 3000. The outer frame 70 includes the first to ninth outer frame elements 71 to 79 described above. Each of the outer frame elements 71 to 79 is formed of a ferrite rod. Each of the outer frame elements 71 to 81 has a width 70W of 3 mm and a protruding height 70H of 3 mm. When viewed in the axial direction, the distances between the first to eighth outer frame elements 71 to 78 and the first to eighth straight portions 11 to 18 of the eighth turn portion 108 are each 0.5 mm. When viewed in the axial direction, the distance between the ninth outer frame element 79 and the eighth straight portion 18 of the seventh turn portion 107 is 0.5 mm. The distance between adjacent outer frame elements 71 to 79 in the circumferential direction is 0.5 mm.

[0178] The individual conditions in the simulations of Examples 1-1 to 1-5 and Comparative Example 1 are as follows. <Example 1-1> The discontinuous portion 85 is not formed in any of the first to ninth outer frame elements 71 to 79. <Example 1-2> A discontinuous portion 85 is formed in the first outer frame element 71 . When viewed in the axial direction, the discontinuous portion 85 does not overlap with the first connection terminal 56 . The width 85W of the discontinuity 85 is 1 mm. <Example 1-3> A discontinuous portion 85 is formed in the first outer frame element 71 . When viewed in the axial direction, the discontinuous portion 85 overlaps with the first connection terminal 56 . The width 85W of the discontinuity 85 is 1 mm. <Example 1-4> A discontinuous portion 85 is formed in the first outer frame element 71 . When viewed in the axial direction, the discontinuous portion 85 overlaps with the first connection terminal 56 . The width 85W of the discontinuity 85 is 15 mm. <Example 1-5> A discontinuous portion 85 is formed in the first outer frame element 71 . When viewed in the axial direction, the discontinuous portion 85 overlaps with the first connection terminal 56 . The width 85W of the discontinuity 85 is 45 mm. <Comparative Example 1> The coil unit does not have either an inner frame 60 or an outer frame 70.

[0179] <Evaluation> The results of Simulation 1 are shown in Fig. 14. In Fig. 14, "Q value," "L," and "Z" refer to the Q value, inductance, and impedance of the coil unit 5. "Joule loss" refers to the loss caused by the current in the coil 10 or the second shield member 50. "Iron loss" refers to the loss caused by the magnetic flux of the first shield member 30. "Total loss" is the sum of "Joule loss" and "Iron loss."

[0180] 14, the loss of the coil unit 5 having the inner frame 60 and the outer frame 70 (coil unit 5 of Examples 1-1 to 1-5) is lower than the loss of the coil unit (coil unit of Comparative Example 1) that does not include the inner frame 60 and the outer frame 70. In particular, the coil units 5 of Examples 1-1 to 1-5 have reduced Joule loss compared to the coil unit of Comparative Example 1.

[0181] Furthermore, as can be seen from FIG. 14, the coil unit 5 having a discontinuous portion 85 in the outer frame 70 (coil unit 5 in Examples 1-2 to 1-5) has significantly reduced iron loss in the first shield member 30 compared to the coil unit 5 having no discontinuous portion 85 in the outer frame 70 (coil unit 5 in Example 1-1).

[0182] Furthermore, as can be seen from FIG. 14, the coil unit 5 in which the discontinuous portion 85 overlaps the first connection terminal 56 when viewed in the axial direction (coil unit 5 in Examples 1-3 to 1-5) has significantly reduced iron loss in the first shield member 30 compared to the coil unit 5 in which the discontinuous portion 85 does not overlap the first connection terminal 56 when viewed in the axial direction (coil unit 5 in Example 1-2).

[0183] <Coil unit 5 performance evaluation simulation 2> The following describes simulations carried out to evaluate the performance of the coil units according to Examples 2-1 to 2-3 and Comparative Example 2. The simulations were carried out using Femtet (registered trademark) manufactured by Murata Software Corporation.

[0184] The common conditions for the simulations of Examples 2-1 to 2-3 and Comparative Example 2 are as follows. The coil unit 5 includes a coil 10 formed in a spiral shape, similar to the example shown in Figures 10 to 13, a magnetic resin layer 20, a magnetic wall portion 25, a first shielding member 30, a second shielding member 50, a first connection terminal 56, and a second connection terminal 57. The coil 10 has a first coil element 10j and a second coil element 10jj. The first coil element 10j and the second coil element 10jj are wound in a generally regular octagonal shape. The first coil element 10j and the second coil element 10jj have first to fifth turn portions 101 to 105, respectively. The distance between adjacent turn portions 101, 102; 104, 105 is 6 mm. Each coil element 10j, jj is made of copper. Each coil element 10j, jj has a line width of 6 mm and a thickness of 0.5 mm. The dimensions of the coil 10 along the first direction D1 and the third direction D3 are 295 mm and 295 mm, respectively. The magnetic resin layer 20 is in close contact with the second main surface 10b of the coil 10. The magnetic resin layer 20 has a relative magnetic permeability of 10. The magnetic wall portion 25 has a relative magnetic permeability of 10. The dimension of the gap between the coil 10 and the first shield member 30 is 1.0 mm. The relative magnetic permeability of the first shield member 30 is 3,000. The first shield member 30 is divided into eight shield pieces 31-38. Each of the shield pieces 31 to 38 is formed of a ferrite plate. Gaps 41 to 48 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31 extend radially from the central axis C. The first to eighth gaps 41 to 48 are perpendicular to the first to eighth straight line portions 11 to 18, respectively, when viewed in the axial direction. The width of the first to eighth gaps 41 to 48 is 5 mm. The dimensions of the first shield member 30 in the first direction D1 and the third direction D3 are 300 mm and 300 mm, respectively. The distance between the magnetic resin layer 20 and the first shield member 30 is 1 mm. The second shield member 50 is made of aluminum. The dimensions of the second shield member 50 in the first direction D1 and the third direction D3 are 320 mm and 320 mm, respectively. The distance between the first shielding member 30 and the second shielding member 50 is 1 mm. The first connection terminal 56 and the second connection terminal 58 are connected to the outermost turn portion 105 of the coil elements 10jj, 10j, respectively. The high frequency current supplied is 40A and the frequency is 85KHz.

[0185] The individual conditions in the simulations of Examples 2-1 to 2-3 and Comparative Example 2 are as follows. <Example 2-1> The coil unit 5 has an inner frame 60 similar to the example shown in FIGS. The relative permeability of the inner frame 60 is 3000. The inner frame 60 includes first to eighth inner frame elements 61-68. Each of the inner frame elements 61 to 68 is formed from a ferrite rod. The width 60W of the inner frame 60 is 3 mm, and the protruding height 60H is 3 mm. When viewed in the axial direction, the distances between the first to eighth inner frame elements 61 to 68 and the first to eighth straight portions 11 to 18 of the first turn portion 101 are each 0.5 mm. The distance between adjacent inner frame elements 61 to 69 in the circumferential direction is 0.5 mm. The coil unit 5 does not have an outer frame 70. <Example 2-2> The coil unit 5 has an outer frame 70 similar to the example shown in FIGS. The relative permeability of the outer frame 70 is 3000. The outer frame 70 includes the first to eighth outer frame elements 71 to 78 described above. Each of the outer frame elements 71 to 78 is formed from a ferrite rod. Each of the outer frame elements 71 to 78 has a width 70W of 3 mm and a protruding height 70H of 3 mm. When viewed in the axial direction, the distances between the first to seventh outer frame elements 71 to 77 and the first to seventh straight portions 11 to 17 of the eighth turn portion 108 are each 0.5 mm. When viewed in the axial direction, the distance between the eighth outer frame element 78 and the turn connection portion 19 of the seventh turn portion 107 is 0.5 mm. The distance between adjacent outer frame elements 71 to 78 in the circumferential direction is 0.5 mm. The eighth outer frame element 78 has discontinuous portions 85 and 86 formed therein. When viewed in the axial direction, the discontinuous portion 85 overlaps with the first connection terminal 56 . The width 85W of the discontinuity 85 is 45 mm. The coil unit 5 does not have an inner frame 60. <Example 2-3> The coil unit 5 has an inner frame 60 and an outer frame 70 similar to the examples shown in FIGS. The relative permeability of the inner frame 60 is 3000. The inner frame 60 includes first to eighth inner frame elements 61-68. Each of the inner frame elements 61 to 68 is formed from a ferrite rod. The width 60W of the inner frame 60 is 3 mm, and the protruding height 60H is 3 mm. When viewed in the axial direction, the distances between the first to eighth inner frame elements 61 to 68 and the first to eighth straight portions 11 to 18 of the first turn portion 101 are each 0.5 mm. The distance between adjacent inner frame elements 61 to 69 in the circumferential direction is 0.5 mm. The relative permeability of the outer frame 70 is 3000. The outer frame 70 includes the first to eighth outer frame elements 71 to 78 described above. Each of the outer frame elements 71 to 78 is formed from a ferrite rod. Each of the outer frame elements 71 to 78 has a width 70W of 3 mm and a protruding height 70H of 3 mm. When viewed in the axial direction, the distances between the first to seventh outer frame elements 71 to 77 and the first to seventh straight portions 11 to 17 of the eighth turn portion 108 are each 0.5 mm. When viewed in the axial direction, the distance between the eighth outer frame element 78 and the turn connection portion 19 of the seventh turn portion 107 is 0.5 mm. The distance between adjacent outer frame elements 71 to 78 in the circumferential direction is 0.5 mm. The eighth outer frame element 78 has discontinuous portions 85 and 86 formed therein. When viewed in the axial direction, the discontinuous portion 85 overlaps with the first connection terminal 56 . The width 85W of the discontinuity 85 is 45 mm. <Comparative Example 2> The coil unit does not have either an inner frame 60 or an outer frame 70.

[0186] <Evaluation> The results of Simulation 2 are shown in Fig. 15. In Fig. 15, "Q value," "L," and "Z" refer to the Q value, inductance, and impedance of the coil unit 5. "Joule loss" refers to the loss caused by the current in the coil 10 or the second shield member 50. "Iron loss" refers to the loss caused by the magnetic flux of the first shield member 30. "Total loss" is the sum of "Joule loss" and "Iron loss."

[0187] 15, the loss of the coil unit 5 having the inner frame 60 and the outer frame 70 (the coil unit 5 of Examples 2-1 to 2-3) is lower than the loss of the coil unit (the coil unit of Comparative Example 2) that does not include the inner frame 60 and the outer frame 70. In particular, the coil units 5 of Examples 2-1 to 2-3 have reduced Joule loss compared to the coil unit of Comparative Example 2.

[0188] 15, the total loss of the coil unit 5 having the inner frame 60 and the outer frame 70 (the coil unit 5 of Examples 2-1 to 2-3) is lower than the total loss of the coil unit (the coil unit of Comparative Example 2) that does not include the inner frame 60 and the outer frame 70. In particular, the coil units 5 of Examples 2-1 to 2-3 have reduced Joule loss compared to the coil unit of Comparative Example 2.

[0189] The coil unit 5 according to the embodiment and its modified example described above includes a coil 10 including coil elements 10i; 10j, 10jj formed in a spiral shape around an arbitrary central axis C, a first shield member 30, and an outer frame 70 extending circumferentially around the outside of the coil 10. The coil 10 has a first main surface 10a and a second main surface 10b that is the surface opposite to the first main surface 10a. The first shield member 30 and the coil 10 are laminated in this order in a first direction AD1 from the second main surface 10b toward the first main surface 10a. The outer frame 70 includes ferrite and protrudes in the first direction AD1 beyond the first main surface 10a of the coil 10. According to such a coil unit 5, the loss of the coil unit 5 (particularly Joule loss) can be suppressed.

[0190] The coil unit 5 according to the embodiment and its modified example further includes an inner frame 60 extending circumferentially inside the coil 10. The inner frame 60 includes ferrite, and protrudes in the first direction AD1 beyond the first main surface 10a of the coil 10. With such a coil unit 5, losses (particularly Joule losses) in the coil unit 5 can be suppressed.

[0191] The coil unit 5 according to the embodiment and its modified example further includes a first connection terminal 56 connected to the coil 10. The coil 10 has an inner end 10e1 close to the central axis C and an outer end 10e2 far from the central axis C. The first connection terminal 56 is connected to the inner end 10e1 on the second main surface 10b side of the coil 10 and extends from the inside to the outside of the coil 10 as viewed in the axial direction. The outer frame 70 is formed with a discontinuous portion 85 that overlaps with the first connection terminal 56 as viewed in the axial direction. With such a coil unit 5, losses (particularly iron loss) of the coil unit 5 can be suppressed.

[0192] In the coil unit 5 according to one embodiment and its modified example, the first shield member 30 is divided into a plurality of shield pieces 30P. The first shield member 30 is formed with gaps 40 that extend linearly between adjacent shield pieces 30P and extend from the inside to the outside of the coil 10 as viewed in the axial direction. The outer frame 70 is formed with discontinuous parts 85 that overlap with the gaps 40 as viewed in the axial direction. With such a coil unit 5, losses (particularly iron loss) in the coil unit 5 can be suppressed.

[0193] Alternatively, the coil unit 5 according to one embodiment and its modified example includes a coil 10 including coil elements 10i; 10j, 10jj formed in a spiral shape around an arbitrary central axis C, a first shield member 30, and an inner frame 60 extending circumferentially inside the coil 10. The coil 10 has a first main surface 10a and a second main surface 10b that is the surface opposite to the first main surface 10a. The first shield member 30 and the coil 10 are layered in this order in a first direction AD1 from the second main surface 10b toward the first main surface 10a. The inner frame 60 includes ferrite and protrudes in the first direction AD1 beyond the first main surface 10a of the coil 10. According to such a coil unit 5, the loss (particularly Joule loss) of the coil unit 5 can be suppressed.

[0194] The coil unit 5 according to the embodiment and its modified example further includes a first connection terminal 56 connected to the coil 10. The coil 10 has an inner end 10e1 close to the central axis C and an outer end 10e2 far from the central axis C. The first connection terminal 56 is connected to the inner end 10e1 on the side of the second main surface 10b of the coil 10, and extends from the inside to the outside of the coil 10 as viewed in the axial direction. The first shield member 30 is divided into a plurality of shield pieces 30P. The first shield member 30 has gaps 40 extending linearly between adjacent shield pieces 30P, and the gaps 40 extend from the inside to the outside of the coil 10. As viewed in the axial direction, the first connection terminal 56 extends within the gaps 40. According to such a coil unit 5, the loss (particularly iron loss) of the coil unit 5 can be suppressed.

[0195] The coil unit 5 according to the modified example further includes a first connection terminal 56 connected to the coil 10. The coil 10 has an inner end 10e1 close to the central axis C and an outer end 10e2 far from the central axis C. The first connection terminal 56 is connected to the inner end 10e1 on the side of the second main surface 10b of the coil 10, and extends from the inside to the outside of the coil 10 as viewed in the axial direction. The first shield member 30 is formed with a notch extending from the inside to the outside of the coil 10 as viewed in the axial direction. As viewed in the axial direction, the first connection terminal 56 extends within the notch. According to such a coil unit 5, losses (particularly iron loss) of the coil unit 5 can be suppressed.

[0196] In the coil unit 5 according to one embodiment and its modified example, the first connection terminal 56 extends from the inside to the outside of the coil 10 at a height position where it overlaps with the first shield member 30 in a side view of the coil unit 5. With such a coil unit 5, losses (particularly iron loss) in the coil unit 5 can be suppressed.

[0197] In the coil unit 5 according to the modified example, the coil elements 10i; 10j, 10jj wind around the central axis C in a first winding direction CD1 from their inner end to their outer end. The area of ​​the shield piece 31 adjacent to the first connection terminal 56 in the first winding direction CD1 is equal to or greater than the area of ​​the shield piece 38 adjacent to the shield piece 31 with the first connection terminal 56 in between. With such a coil unit 5, losses (particularly iron loss) in the coil unit 5 can be suppressed.

[0198] In the coil unit 5 according to the modified example, the coil elements 10i; 10j, 10jj wind around the central axis C in a first winding direction CD1 from their inner end to their outer end. The area of ​​the shield piece 31 adjacent to the first connection terminal 56 in the first winding direction CD1 is equal to or greater than the area of ​​the shield piece 32 adjacent to the shield piece 31 in the first winding direction CD1. With such a coil unit 5, losses (especially iron loss) in the coil unit 5 can be suppressed.

[0199] Although several modifications to the above-mentioned embodiment have been described, it is of course possible to apply a plurality of modifications in appropriate combination. [Explanation of symbols]

[0200] 1 Power transmission equipment 2 Power receiving device 5 Coil unit 10 Coil 10a First main surface 10b Second main surface 10i, 10j, 10jj Coil elements 11 1st straight section 11G 1st straight line group 12 2nd straight section 12G 2nd straight line group 13 3rd straight section 13G 3rd straight line group 14 4th straight section 14G 4th straight line group 15 5th straight section 15G 5th straight line group 16 6th straight section 16G 6th straight line group 17 7th straight section 17G 7th straight line group 18 8th straight section 18G 8th straight line group 19 Turn connection 19G Turn connection group 20 Magnetic resin layer 30 First shield member 30P Shield piece 40 gap 50 Second shield member 60 Inner Frame 70 Outer Frame 85 Discontinuity 101 First Turn 102 2nd Turn 103 Third Turn 104 4th Turn 105 5th Turn 106 Turn 6 107 Turn 7 108 Turn 8 C center axis S Wireless power transmission system

Claims

1. A coil including a coil element formed in a spiral shape around a central axis, a first shield member, and an outer frame extending circumferentially outside the coil, The coil has a first main surface and a second main surface that is a surface opposite to the first main surface, the first shield member and the coil are laminated in this order in a first direction from the second main surface toward the first main surface, The outer frame includes ferrite and protrudes in the first direction beyond the first main surface of the coil.

2. Further comprising an inner frame extending circumferentially inside the coil, The coil unit according to claim 1 , wherein the inner frame includes ferrite and protrudes in the first direction beyond the first main surface of the coil.

3. The coil unit according to claim 1 , wherein the outer frame is positioned more inward than an outer edge of the first shield member when viewed in the axial direction.

4. A first connection terminal connected to the coil, the coil has an inner end proximate the central axis and an outer end distal to the central axis; the first connection terminal is connected to the inner end of the coil and extends from the inner side to the outer side of the coil when viewed in the axial direction; The coil unit according to claim 1 , wherein the outer frame has a discontinuous portion formed therein that overlaps with the first connection terminal when viewed in the axial direction.

5. The first shield member is divided into a plurality of shield pieces, The first shield member has a gap extending linearly between adjacent shield pieces, the gap extending from the inside to the outside of the coil when viewed in the axial direction, The coil unit according to claim 1 , wherein the outer frame has a discontinuous portion formed therein that overlaps with the gap when viewed in the axial direction.

6. The coil unit according to claim 4 or 5, wherein the width of the discontinuous portion is 0.8 mm or more.

7. The coil unit according to claim 4 or 5, wherein the width of the discontinuous portion is 5 mm or more.

8. The coil unit according to claim 1 , wherein the relative magnetic permeability of the outer frame is 1000 or more.

9. The coil unit according to claim 1 , wherein a protruding height of the outer frame protruding in the first direction beyond the first main surface is 1 mm or more.

10. The coil unit according to claim 1 , wherein the width of the outer frame is equal to or greater than 3 mm and equal to or less than 10 mm.

11. The coil unit according to claim 1 , wherein the distance between the outer frame and the coil is 3 mm or less when viewed in the axial direction.

12. The coil unit according to claim 2 , wherein the distance between the inner frame and the coil is 3 mm or less when viewed in the axial direction.

13. The coil unit according to claim 2 , wherein the inner frame has a relative magnetic permeability of 1000 or more.

14. A coil including a coil element formed in a spiral shape around a central axis, a first shield member, and an inner frame extending circumferentially inside the coil, The coil has a first main surface and a second main surface that is a surface opposite to the first main surface, the first shield member and the coil are laminated in this order in a first direction from the second main surface toward the first main surface, The inner frame includes ferrite and protrudes in the first direction beyond the first main surface of the coil.

15. The coil unit according to claim 14 , wherein the inner frame has a relative magnetic permeability of 1000 or more.

16. The coil unit according to claim 14 , wherein a protruding height of the inner frame protruding in the first direction beyond the first main surface is 1 mm or more.

17. The coil unit according to claim 14, wherein the width of the inner frame is not less than 3 mm and not more than 10 mm.

18. The coil unit according to claim 14 , wherein the distance between the inner frame and the coil is 3 mm or less when viewed in the axial direction.

19. The coil unit according to claim 1 or 14, wherein the first shield member includes ferrite.

20. The coil unit according to claim 1 or 14, wherein the first shield member is divided into a plurality of shield pieces.

21. The coil unit includes a magnetic resin layer that is in direct contact with the second main surface of the coil. The coil unit according to claim 20 .

22. The coil unit according to claim 21 , wherein the magnetic resin layer has a relative magnetic permeability of 5 or more and 30 or less.

23. A first connection terminal connected to the coil, the coil has an inner end proximate the central axis and an outer end distal to the central axis; the first connection terminal is connected to the inner end portion on the second main surface side of the coil and extends from the inner side to the outer side of the coil when viewed in the axial direction; The first shield member is divided into a plurality of shield pieces, The first shield member has a gap extending linearly between adjacent shield pieces, the gap extending from the inside to the outside of the coil, The coil unit according to claim 1 or 14, wherein the first connection terminal extends within the gap when viewed in the axial direction.

24. The coil unit according to claim 23 , wherein the first connection terminal extends from the inside to the outside of the coil at a height position where the first connection terminal overlaps with the first shield member in a side view of the coil unit.

25. A first connection terminal connected to the coil, the coil has an inner end proximate the central axis and an outer end distal to the central axis; the first connection terminal is connected to the inner end portion on the second main surface side of the coil and extends from the inner side to the outer side of the coil when viewed in the axial direction; The first shield member has a notch formed therein, the notch extending from the inside to the outside of the coil as viewed in the axial direction, The coil unit according to claim 1 or 14, wherein the first connection terminal extends within the notch when viewed in the axial direction.

26. The coil unit according to claim 25 , wherein the first connection terminal extends from the inside to the outside of the coil at a height position where the first connection terminal overlaps with the first shield member in a side view of the coil unit.

27. The coil element winds around the central axis in a first winding direction from an inner end to an outer end, 24. The coil unit according to claim 23, wherein an area of ​​a shield piece adjacent to the first connection terminal in the first winding direction is greater than or equal to an area of ​​a shield piece adjacent to the first connection terminal and sandwiching the first connection terminal therebetween.

28. The coil element winds around the central axis in a first winding direction from an inner end to an outer end, The coil unit according to claim 23 , wherein an area of ​​a shield piece adjacent to the first connection terminal in the first winding direction is equal to or larger than an area of ​​a shield piece adjacent to the first connection terminal in the first winding direction.

29. A power transmitting device comprising the coil unit according to claim 1 or 14.

30. A power receiving device comprising the coil unit according to claim 1 or 14.

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

32. A moving body comprising the coil unit according to claim 1 or 14.

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