Coil components, power transmission equipment, power receiving equipment, mobile units, and power transmission systems

Abstract

To improve a production efficiency of a coil component.SOLUTION: In a power transmission system, a coil component 5 comprises a coil 10 containing first and second flat surface coil elements 11 and 12. Each of the first and second flat surface coil elements has a spiral shape having a plurality of turn parts 111 to 116, and 121 to 123. Each of the first and second flat surface coil elements is arranged opposing to each other in a shaft direction extending on center shaft wires C1 and C2 in this spiral shape. The first and second flat surface coil elements is serially connected to each other. The number of turns of the second flat surface coil element is smaller than the number of turns of the first flat surface coil element. Also, in view of the shaft direction, at least one of the plurality of turn parts of the second flat surface coil element is overlapped to two or more of the plurality of turn parts of the first flat surface coil element. Also, each gap between the plurality of turn parts of the second flat surface coil element in the shaft direction is overlapped with any one of the gaps between the plurality of turn parts of the first flat surface coil element.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a coil component, a power transmission device, a power reception device, a moving body, and a power transmission system.

Background Art

[0002] Wireless power transmission systems that transmit power without contact are becoming widespread.

[0003] When transmitting power without contact, a high-frequency current flows through a resonance circuit including a coil. A coil component used in such a resonance circuit is disclosed in Patent Document 1. The coil component disclosed in Patent Document 1 uses a coil formed by laminating two spiral and plate-shaped planar coil elements. Thereby, the dimensions of the coil in a plan view can be reduced.

[0004] When forming a coil as a laminate of two planar coil elements, as disclosed in Patent Document 1, two planar coil elements having the same or corresponding patterns (that is, the number of turns and the pitch of the turn portions are the same) are produced, and these are stacked vertically and electrically connected.

Prior Art Documents

Patent Documents

[0005] [[ID=Z29]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] On the other hand, it is required to improve the manufacturing efficiency of the coil component. The manufacturing efficiency of the coil component can be improved, for example, by improving the handleability of the members constituting the coil component. In particular, in the case of a coil component having a small thickness of the planar coil element, it has been a problem that it is difficult to handle the planar coil element when assembling the coil component.

[0007] The embodiments of this disclosure aim to improve the manufacturing efficiency of coil components. [Means for solving the problem]

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

[19] .

[0009] [1] The coil comprises a first planar coil element and a second planar coil element, each having a spiral shape with multiple turns, and arranged opposite to each other in the axial direction extending along the central axis of the spiral shape, and connected in series with each other. The number of turns of the second planar coil element is less than the number of turns of the first planar coil element. Viewed in the axial direction, at least one of the plurality of turns of the second planar coil element overlaps with two or more of the plurality of turns of the first planar coil element. A coil component in which, when viewed in the axial direction, each gap between the plurality of turns of the second planar coil element overlaps with any of the gaps between the plurality of turns of the first planar coil element.

[0010] [2] The number of turns of the first planar coil element is twice the number of turns of the second planar coil element. The coil component as described in [1], wherein, when viewed in the axial direction, each turn portion of the second planar coil element overlaps with the two turn portions of the first planar coil element.

[0011] [3] The coil component according to [1] or [2], wherein, when viewed in the axial direction, the inner edge of each turn portion of the second planar coil element overlaps with the inner edge of any turn portion of the first planar coil element, and the outer edge of each turn portion of the second planar coil element overlaps with the outer edge of any turn portion of the first planar coil element.

[0012] [4] The coil component according to any one of [1] to [3], wherein the plurality of turns of the second planar coil element have elongated holes extending along the turns.

[0013] [5] The coil component according to [4], wherein the elongated hole extends along the spiral shape of the second planar coil element.

[0014] [6] The coil component according to [4] or [5], wherein, viewed in the axial direction, the elongated hole overlaps with any of the gaps between the plurality of turns of the first planar coil element.

[0015] [7] The coil component according to any one of [1] to [6], wherein the thickness of the second planar coil element is 0.15 mm or more and 0.35 mm or less.

[0016] [8] The coil component according to any one of [1] to [7], further comprising a magnetic shielding member disposed opposite to the second planar coil element.

[0017] [9] The device further comprises magnetic wall portions that extend along the axial direction and along the gaps between the multiple turns of the first planar coil element when viewed in the axial direction, The coil component according to [8], wherein the magnetic material wall portion is positioned opposite to the second surface of the first planar coil element that is opposite to the first surface facing the second planar coil element.

[0018]

[10] The device further comprises magnetic wall portions that extend along the axial direction and along the gaps between the multiple turns of the first planar coil element when viewed in the axial direction, The coil component according to [8], wherein the magnetic wall portion extends along the axial direction from one side of the first planar coil element to the other side, passing through the gaps between the plurality of turns of the first planar coil element.

[0019]

[11] The coil component according to any one of [1] to [7], further comprising a magnetic shield member disposed opposite to the first planar coil element.

[0020]

[12] The coil component further comprises a magnetic wall portion that extends along the axial direction and extends along a gap between a plurality of turn portions of the second planar coil element as viewed in the axial direction. The coil component according to

[11] , wherein the magnetic wall portion is disposed opposite to a fourth surface of the second planar coil element opposite to a third surface facing the first planar coil element.

[0021]

[13] The coil component further comprises a magnetic wall portion that extends along the axial direction and extends along a gap between a plurality of turn portions of the second planar coil element as viewed in the axial direction. The coil component according to

[11] , wherein the magnetic wall portion extends along the axial direction from one side to the other side of the second planar coil element through a gap between a plurality of turn portions of the second planar coil element.

[0022]

[14] A long hole is formed in the plurality of turn portions of the second planar coil element, extending along the turn portion. The coil component further comprises an additional magnetic wall portion. The additional magnetic wall portion extends along the axial direction and extends along the long hole as viewed in the axial direction. The coil component according to any one of

[11] to

[13] , wherein the additional magnetic wall portion is disposed opposite to a fourth surface of the second planar coil element opposite to a third surface facing the first planar coil element.

[0023]

[15] A long hole is formed in the plurality of turn portions of the second planar coil element, extending along the turn portion. The coil component further comprises an additional magnetic wall portion. [[ID= The method for manufacturing a coil component according to any one of

[11] to

[13] , wherein the additional magnetic wall portion extends along the axial direction from one side of the second planar coil element to the other side through the elongated holes formed in a plurality of turns of the second planar coil element.

[0024]

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

[15] .

[0025]

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

[15] .

[0026]

[18] A mobile body equipped with the power receiving device described in

[17] .

[0027]

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

[15] . [Effects of the Invention]

[0028] According to one embodiment of the present disclosure, the manufacturing efficiency of coil components can be improved. [Brief explanation of the drawing]

[0029] [Figure 1] This figure schematically shows a wireless power transmission system to which a coil component according to one embodiment is applied. [Figure 2] This is a perspective view of a coil component according to one embodiment. [Figure 3] Figure 2 is a cross-sectional view of the coil component along line III-III. [Figure 4] Figure 3 is an exploded perspective view of the coil component shown in the coil. [Figure 5] This figure corresponds to Figure 3 and is a cross-sectional view showing a modified example of a coil component. [Figure 6] This figure corresponds to Figure 3 and is a cross-sectional view showing another modified example of the coil component. [Figure 7] Figure 6 shows an exploded perspective view of the coil component of the coil. [Figure 8] This figure corresponds to Figure 3 and is a cross-sectional view showing yet another variation of the coil component. [Figure 9] This figure corresponds to Figure 3 and is a cross-sectional view showing yet another variation of the coil component. [Figure 10] Figure 9 is an exploded perspective view of the coil component of the coil. [Figure 11] This figure corresponds to Figure 3 and is a cross-sectional view showing yet another variation of the coil component. [Figure 12] This figure corresponds to Figure 2 and is a perspective view showing yet another variation of the coil component. [Figure 13] Figure 12 is a cross-sectional view of the coil component along the line XIII-XIII. [Figure 14] Figure 13 is an exploded perspective view of the coil component shown in Figure 13. [Figure 15] This figure corresponds to Figure 13 and is a cross-sectional view showing yet another variation of the coil component. [Figure 16] This figure corresponds to Figure 3 and shows cross-sections of coil components according to Comparative Examples 1 to 3. [Figure 17] This figure corresponds to Figure 3 and shows a cross-section of the coil component according to Comparative Example 4. [Figure 18] This figure corresponds to Figure 3 and shows a cross-section of the coil component according to Comparative Example 5. [Figure 19] This figure corresponds to Figure 3 and shows a cross-section of the coil component according to Comparative Example 6. [Figure 20] This table shows the performance of the coil components in Examples 1-4 and Comparative Examples 1-6. [Figure 21] This graph shows the performance of the coil components in Examples 1-4 and Comparative Examples 1-6. [Modes for carrying out the invention]

[0030] An embodiment and its modified forms will be described below with reference to the drawings. Note that, for the sake of illustration and ease of understanding, the scale and aspect ratios of the drawings attached to this specification have been appropriately altered and exaggerated from those of the actual objects.

[0031] Furthermore, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from each other solely based on differences in name. Therefore, for example, "sheet" is a concept that includes components that could also be called films or plates.

[0032] Figure 1 schematically shows a wireless power transmission system S to which a coil component 5 according to one embodiment is applied. First, the wireless power transmission system S (hereinafter abbreviated as power transmission system S) will be described with reference to Figure 1. It goes without saying that a coil component other than the coil component 5 according to this embodiment may be applied to the power transmission system S.

[0033] <Wireless Power Transmission System> The power transmission system S comprises a power transmission device 1 and a power receiving device 2. The power transmission device 1 includes a coil component 5 and a high-frequency current supply unit 1A. The coil component 5 in the power transmission device 1 functions as a power transmission coil component. The high-frequency current supply unit 1A supplies high-frequency current to the coil component 5 as a power transmission coil component.

[0034] The power receiving device 2 includes a coil component 5 and a conversion unit 2A. The coil component 5 in the power receiving device 2 functions as a power receiving coil component. The conversion unit 2A shapes the high-frequency current generated in the coil component 5. The conversion unit 2A has a rectifier circuit and the like that converts the high-frequency current into a DC current. The conversion unit 2A may include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0035] In this embodiment, both the power transmission device 1 and the power receiving device 2 include a coil component 5. However, the coil component 5 may be used in only one of the power transmission device 1 or the power receiving device 2, while a different type of coil component is used in the other.

[0036] When transmitting power wirelessly (contactlessly) from the power transmission device 1 to the power receiving device 2, the power transmission device 1 supplies a high-frequency current of a predetermined frequency to the coil component 5, which acts as a power transmission coil component, from the high-frequency current supply unit 1A. At this time, a magnetic field is generated in the coil component 5 due to electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil component 5, which acts as a power receiving coil component, in the power receiving device 2. That is, the power receiving device 2 receives a magnetic field from the power transmission device 1 or is influenced by the magnetic field in the power transmission device 1, and causes a high-frequency current to flow due to electromagnetic induction. The conversion unit 2A converts this high-frequency current into a DC current and supplies the converted DC current to, for example, a battery (not shown).

[0037] The power transmission system S shown in Figure 1 employs a magnetic resonance method as the power transmission method. However, the coil component 5 in this embodiment may also be used in an electromagnetic induction power transmission system. Furthermore, the power transmission system S is configured as a system for wirelessly transmitting power to an electric vehicle. In this case, the power transmission device 1 is installed on a road, parking lot, etc. The power receiving device 2 is installed in the electric vehicle.

[0038] However, the applications of the power transmission system S are not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to flying objects such as drones and robots. Furthermore, the power transmission system S may be used to transmit power to submersibles and exploration robots in the ocean. Thus, the power transmission system S can be used to transmit power to various mobile objects such as electric vehicles, flying objects, robots, and submersibles. Also, the applications of the coil component 5 are not limited to wireless power transmission systems. For example, the coil component 5 may be used in transformers, DC-DC converters, antennas, etc.

[0039] <Coil components> The coil component 5 will be described below. Figure 2 is a perspective view of the coil component 5. Figure 3 is a cross-sectional view of the coil component 5 along the line III-III in Figure 2. Figure 4 is an exploded perspective view of the coil 10 provided by the coil component 5.

[0040] As shown in Figures 2 and 3, the coil component 5 comprises a coil 10, a magnetic shielding member 20, a holder 30, a magnetic wall portion 40, a first connection terminal 51, and a second connection terminal 52.

[0041] As shown in Figure 3, the coil 10 includes a back surface 10a facing the magnetic shielding member 20 and a front surface 10b opposite to the back surface 10a. The coil 10 also includes a first planar coil element 11 and a second planar coil element 12. In the example shown in Figure 3, the first planar coil element 11 forms the front surface 10b, and the second planar coil element 12 forms the back surface 10a. In other words, in the coil component 5 shown in Figure 3, the second planar coil element 12 and the first planar coil element 11 are arranged on the magnetic shielding member 20 in this order. The first planar coil element 11 and the second planar coil element 12 are connected in series and overlap with a gap between them. The second planar coil element 12 and the magnetic shielding member 20 also overlap with a gap between them.

[0042] The holder 30 functions to maintain the gap between the first planar coil element 11 and the second planar coil element 12, as well as the gap between the second planar coil element 12 and the magnetic shielding member 20. The holder 30 also has the function of integrating the first planar coil element 11 and the second planar coil element 12.

[0043] (First planar coil element and second planar coil element) The first planar coil element 11 and the second planar coil element 12 are spiral-shaped, as shown in Figures 2 and 4. The first planar coil element 11 and the second planar coil element 12 are formed from a conductive material. In this embodiment, the first planar coil element 11 and the second planar coil element 12 contain copper. Specifically, the first planar coil element 11 and the second planar coil element 12 are formed from copper. However, the first planar coil element 11 and the second planar coil element 12 may be formed from a copper alloy, aluminum, aluminum alloy, etc. The first planar coil element 11 and the second planar coil element 12 may be formed from different conductive materials.

[0044] The first planar coil element 11 and the second planar coil element 12 are plate-shaped, as shown in Figures 3 and 4. As shown in Figure 3, the cross-sectional shape of the first planar coil element 11 in a direction perpendicular to the direction in which it circulates in a spiral shape is rectangular. Similarly, the cross-sectional shape of the second planar coil element 12 in a direction perpendicular to the direction in which it circulates in a spiral shape is rectangular.

[0045] The first planar coil element 11 has a first surface 11a facing the second planar coil element 12, and a second surface 11b opposite to the first surface 11a. In the example shown in Figure 4, the second surface 11b forms the front surface 10b of the coil 10.

[0046] The second planar coil element 12 has a third surface 12a facing the first planar coil element 11 and a fourth surface 12b opposite to the third surface 12a. In the example shown in Figure 4, the fourth surface 12b forms the back surface 10a of the coil 10.

[0047] The symbol C1 shown in Figures 2 to 4 indicates the first central axis of the first planar coil element 11, passing through the center of the spiral shape of the first planar coil element 11. Hereinafter, "axial direction of the first planar coil element 11" means the direction extending along the first central axis C1 or the direction parallel to the first central axis C1. Furthermore, "radial direction of the first planar coil element 11" means the radial direction of a circle drawn on a plane perpendicular to the first central axis C1, with any point on the first central axis C1 as the center. Furthermore, the radially inward direction of the first planar coil element 11 and the turn portion 11n constituting it means the direction approaching the first central axis C1 in that radial direction. Furthermore, the radially outward direction of the first planar coil element 11 and the turn portion 11n means the direction away from the first central axis C1 in that radial direction.

[0048] Furthermore, the symbol C2 shown in Figures 2 to 4 indicates the second central axis of the second planar coil element 12, which passes through the center of the spiral shape of the second planar coil element 12. Hereinafter, "axial direction of the second planar coil element 12" means the direction extending along the second central axis C2 or the direction parallel to the second central axis C2. Also, "radial direction of the second planar coil element 12" means the radial direction of a circle drawn on a plane perpendicular to the second central axis C2, with any point on the second central axis C2 as the center. Furthermore, the radial inward direction of the second planar coil element 12 and the turn portion 12n constituting it means the direction approaching the second central axis C2 in that radial direction. Furthermore, the radial outward direction of the second planar coil element 12 and the turn portion 12n means the direction moving away from the second central axis C2 in that radial direction.

[0049] In this embodiment, the second planar coil element 12 is arranged to be coaxial with the first planar coil element 11. That is, the first central axis C1 of the first planar coil element 11 and the second central axis C2 of the second planar coil element 12 coincide. In other words, the first central axis C1 and the second central axis C2 are located on the same straight line.

[0050] The first planar coil element 11 has a conductor 11E that forms a spiral shape with a plurality of turned portions 11n. The plurality of turned portions 11n of the first planar coil element 11 are arranged in a direction perpendicular to the first central axis C1 of the spiral shape. Specifically, the plurality of turned portions 11n are connected so as to move radially outward from the first central axis C1 of the spiral shape, gradually moving away from the first central axis C1. This forms the spiral shape.

[0051] The turn section 11n basically has a shape in which the linear conductor portion does not form a ring but rotates 360 degrees around the first central axis C1. In the case of a so-called planar coil, both ends of the turn section 11n are offset in the radial direction. In the case of multiple turn sections 11n, the radially inward end of one turn section 11n is connected to the radially outward end of another turn section 11n, and the other turn sections 11n extend away from the first central axis C1.

[0052] In the following, the turn section 11n closest to the first central axis C1 may be referred to as turn section 111. The turn section connected to turn section 111 may be referred to as turn section 112. When explaining matters common to all of the turn sections 11n in the following, they will generally be referred to simply as turn section 11n.

[0053] In this embodiment, the turn section 11n rotates in a rectangular shape. However, the turn section 11n may also rotate in a circular shape. In this specification and disclosure, the spiral shape refers to the shape of a spirally wound planar curve. The planar curve referred to here also includes a planar pattern that repeatedly rotates while bending in a broken line shape, as shown in the figure. In other words, the spiral shape refers to the shape of a planar curve that moves away from the center (or approaches the center) as it rotates.

[0054] Similarly, the second planar coil element 12 has a conductor 12E that forms a spiral shape with a plurality of turned portions 12n. The plurality of turned portions 12n of the second planar coil element 12 are arranged in a direction perpendicular to the second central axis C2 of the spiral shape. Specifically, the plurality of turned portions 12n are connected so as to move radially outward from the second central axis C2 of the spiral shape and gradually move away from the second central axis C2. This forms the spiral shape.

[0055] The turn section 12n basically has a shape in which the linear conductor portion does not form a ring but rotates 360 degrees around the second central axis C2. In the case of a so-called planar coil, both ends of the turn section 12n are offset in the radial direction. In the case of multiple turn sections 12n, the radially inward end of one turn section 12n is connected to the radially outward end of another turn section 12n, and the other turn sections 12n extend away from the second central axis C2.

[0056] In the following, the turn section 12n closest to the second central axis C2 may be referred to as turn section 121. The turn section connected to turn section 121 may be referred to as turn section 122. When explaining matters common to all of the turn sections 12n, they will generally be referred to simply as turn section 12n.

[0057] In this embodiment, the shape of the second planar coil element 12 corresponds to the shape of the first planar coil element 11. Specifically, if the turn portion 11n circulates in a rectangular shape as shown in the illustrated example, the turn portion 12n also circulates in a rectangular shape similar to the turn portion 11n. Alternatively, if the turn portion 11n has a circular shape, the turn portion 12n may also circulate in a circular shape similar to the turn portion 11n.

[0058] In this embodiment, the first central axis C1 is determined as follows. First, starting from the radially inward end of the innermost turn portion 111, linear virtual turn portions similar in shape to the innermost turn portion 111 are sequentially drawn radially inward to form a spiral shape. Drawing is continued until a virtual turn portion that fits within a diameter of 1 cm can be drawn. The line that passes through the radially inward region of the virtual turn portion that fits within a diameter of 1 cm in directions perpendicular to the circumferential and radial directions of the spiral shape is determined as the first central axis C1. The second central axis C2 is determined in the same way as the first central axis C1. First, starting from the radially inward end of the innermost turn portion 121, linear virtual turn portions similar in shape to the innermost turn portion 121 are sequentially drawn radially inward to form a spiral shape. Drawing is continued until a virtual turn portion that fits within a diameter of 1 cm can be drawn. Then, a line passing through the radially inner region of the virtual turn section, which fits within a diameter of 1 cm, in a direction perpendicular to the circumferential and radial directions of the spiral shape, is defined as the second central axis C2.

[0059] The radially inward end of the first planar coil element 11 (the end closest to the first central axis C1) is electrically connected to the radially inward end of the second planar coil element 12 (the end closest to the second central axis C2). The connecting wiring section 14 shown in Figure 2 is a conductor and electrically connects the first planar coil element 11 and the second planar coil element 12 in series. When the first planar coil element 11 and the second planar coil element 12 are connected, the direction in which the first planar coil element 11 circulates from the end of the first planar coil element 11 that is not connected to the second planar coil element 12 (the radially outward end of the first planar coil element 11) to the end connected to the second planar coil element 12 is the same as the direction in which the second planar coil element 12 circulates from the end of the second planar coil element 12 that is not connected to the first planar coil element 11 (the radially outward end of the second planar coil element 12).

[0060] The illustrated connection wiring section 14 is formed integrally with the first planar coil element 11 as an example. The connection wiring section 14 may be connected to the second planar coil element 12 by ultrasonic connection or the like. On the other hand, the radially outer end of the first planar coil element 11 (the end furthest from the first central axis C1) is connected to the first connection terminal 51. Also, the radially outer end of the second planar coil element 12 (the end furthest from the second central axis C2) is connected to the second connection terminal 52.

[0061] In this embodiment, the first planar coil element 11 and the second planar coil element 12 are formed by punching out a spiral shape from a metal plate such as a copper plate or an aluminum plate. However, the first planar coil element 11 and the second planar coil element 12 can also be formed by etching a metal foil such as copper foil or aluminum foil into a spiral shape.

[0062] The thickness of the first planar coil element 11 and the second planar coil element 12 (the thickness of the conductors 11E and 12E) is measured along the axial direction of the first planar coil element 11 and the second planar coil element 12. The thickness of the first planar coil element 11 and the second planar coil element 12 (the thickness of the conductors 11E and 12E) may be, for example, 0.1 mm or more and 1.0 mm or less, 0.2 mm or more and 0.7 mm or less, or 0.3 mm or more and 0.4 mm or less. The thickness of the first planar coil element 11 and the second planar coil element 12 (the thickness of the conductors 11E and 12E) may be, for example, 0.15 mm or more and 0.35 mm or less. The thickness of the first planar coil element 11 (the thickness of the conductor 11E) may be the same as the thickness of the second planar coil element 12, or it may be smaller or larger than the thickness of the second planar coil element 12. In other words, the thickness of the second planar coil element 12 (the thickness of the conductor 12E) may be the same as the thickness of the first planar coil element 11, or it may be greater than or less than the thickness of the first planar coil element 11.

[0063] Furthermore, the radius of the first planar coil element 11 (the distance from the first central axis C1 to the part furthest in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less. Also, the aspect ratio of the first planar coil element 11 (conductor 11E) having a rectangular cross-sectional shape is determined by dividing the line width of the first planar coil element 11 (conductor 11E) (the radial width of each turn portion 11n) by the thickness of the first planar coil element 11 (conductor 11E). The aspect ratio of the first planar coil element 11 (conductor 11E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0064] Similarly, the radius of the second planar coil element 12 (the distance from the second central axis C2 to the part furthest in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less. Furthermore, the aspect ratio of the second planar coil element 12 (conductor 12E) with a rectangular cross-sectional shape is determined by dividing the line width of the second planar coil element 12 (conductor 12E) (the radial width of each turn portion 12n) by the thickness of the second planar coil element 12 (conductor 12E). The aspect ratio of the second planar coil element 12 (conductor 12E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0065] The thickness and line width of the conductors 11E and 12E may be measured by cutting the coil component 5 axially to expose the conductors 11E and 12E in a cross-section, and measuring each part of the conductors 11E and 12E with a ruler or similar tool, or by analyzing the cross-sectional image. Alternatively, the first planar coil element 11 and the second planar coil element 12 may be removed from the coil component 5, and the thickness of the conductors 11E and 12E may be measured with a ruler, calipers, or the like.

[0066] The first planar coil element 11 and the second planar coil element 12 overlap with a gap between them. This gap may be between 0.5 mm and 1.5 mm. The dimensions of the gap are not particularly limited, but if the gap becomes too large, the thinning of the coil component 5 will be compromised.

[0067] The number of turns of coil 10 (the sum of the number of turns T1 of the first planar coil element 11 and the number of turns T2 of the second planar coil element 12) is determined considering the performance required of the coil component 5. More specifically, it is determined so that the coil component 5 has an appropriate inductance. For example, when the coil component 5 is applied to a system S that wirelessly transmits power to an electric vehicle, the inductance of the coil component 5 is preferably around 35Hz to 50Hz. In this case, the number of turns of coil 10 is, for example, around 8 to 10. However, the number of turns of coil 10 is not limited to this. The number of turns of coil 10 may be, for example, 6 or more and 24 or less.

[0068] Here, there is a need to improve the manufacturing efficiency of the coil component 5. For this reason, improvements in the handling of the materials that make up the coil component 5 are being considered.

[0069] Considering these circumstances, in this embodiment, the number of turns T2 of the second planar coil element 12 is determined to be less than the number of turns T1 of the first planar coil element 11. This improves the handling of the second planar coil element 12. That is, compared to the case where the first planar coil element 11 and the second planar coil element 12 have the same number of turns, the number of turns T2 of the second planar coil element 12 is reduced, making it easier to handle the second planar coil element 12. In the illustrated example, the number of turns T1 of the first planar coil element 11 is twice the number of turns T2 of the second planar coil element 12. More specifically, in the illustrated example, the number of turns of coil 10 is about 8 to 10, and based on this, the number of turns T1 of the first planar coil element 11 is set to 6, and the number of turns T2 of the second planar coil element 12 is set to 3. In other words, the multiple turn sections 11n are composed of 6 turn sections 111 to 116. Furthermore, the multiple turn sections 12n are composed of three turn sections 121 to 123.

[0070] Furthermore, in the illustrated example, the line width of the second planar coil element 12 is greater than that of the first planar coil element 11. This reduces the risk of deformation of the second planar coil element 12 when handling it. Therefore, the handling of the second planar coil element 12 is improved. In addition, the electrical resistance of the second planar coil element 12 can be reduced. In particular, in the illustrated example, the line width of the second planar coil element 12 positioned facing the magnetic shielding member 20 is more than twice that of the first planar coil element 11.

[0071] The inventors of this invention have found that by arranging the plurality of turns 111 to 116 of the first planar coil element 11 and the plurality of turns 121 to 123 of the second planar coil element 12 as follows, it is possible to prevent the Q value of the coil component 5 from being significantly lower than that of a conventional coil component with a similar number of turns. Specifically, in the axial direction, at least one of the plurality of turns 121 to 123 of the second planar coil element 12 overlaps with two or more of the plurality of turns 111 to 116 of the first planar coil element 11, and in the axial direction, each gap between the plurality of turns 121 to 123 of the second planar coil element 12 overlaps with any of the gaps between the plurality of turns 111 to 116 of the first planar coil element 11.

[0072] In the illustrated example, each turn portion 12n of the second planar coil element 12 is positioned to overlap with two adjacent turn portions of the first planar coil element 11 when viewed in the axial direction. In the illustrated example, when viewed in the axial direction, turn portion 121 overlaps with turn portions 111 and 112. Also, when viewed in the axial direction, turn portion 122 overlaps with turn portions 113 and 114. Also, when viewed in the axial direction, turn portion 123 overlaps with turn portions 115 and 116.

[0073] Furthermore, in the illustrated example, when viewed in the axial direction, the gap between the turn sections 121 and 122 overlaps with the gap between the turn sections 112 and 113. Also, when viewed in the axial direction, the gap between the turn sections 122 and 123 overlaps with the gap between the turn sections 114 and 115.

[0074] Furthermore, in the illustrated example, when viewed in the axial direction, the edges of each turn portion 12n of the second planar coil element 12 overlap with the edges of any of the turn portions of the first planar coil element 11. More specifically, the inner edges of each turn portion 12n of the second planar coil element 12 overlap with the inner edges of any of the turn portions of the first planar coil element 11. Also, the outer edges of each turn portion 12n of the second planar coil element 12 overlap with the outer edges of any of the turn portions of the first planar coil element 11. In the illustrated example, the inner edge of turn portion 121 overlaps with the inner edge of turn portion 111. The outer edge of turn portion 121 overlaps with the outer edge of turn portion 112. The inner edge of turn portion 122 overlaps with the inner edge of turn portion 113. The outer edge of turn portion 122 overlaps with the outer edge of turn portion 114. The inner edge of the turn portion 123 overlaps with the inner edge of the turn portion 115. The outer edge of the turn portion 123 overlaps with the outer edge of the turn portion 116.

[0075] The ratio of the number of turns T1 of the first planar coil element 11 to the number of turns T2 of the second planar coil element is not limited to 2:1. For example, the ratio may be 3:1. Also, the number of turns T1 of the first planar coil element 11 does not have to be an integer multiple of the number of turns T2 of the second planar coil element 12. For example, the number of turns T1 of the first planar coil element 11 may be 5, and the number of turns T2 of the second planar coil element 12 may be 3. In this case, the line width of some of the turns of the second planar coil element 12 may differ from the line width of other turns, so that when viewed in the axial direction, the gaps between each of the multiple turns 121 to 123 of the second planar coil element 12 overlap with one of the gaps between the multiple turns of the first planar coil element 11. For example, the width of each turn portion 12n of the second planar coil element 12 may be determined such that turn portion 121 overlaps with turn portion 111, turn portion 122 overlaps with turn portions 112 and 113, and turn portion 123 overlaps with turn portions 114 and 115.

[0076] The line width of the first planar coil element 11 (conductor 11E), that is, the radial width (width in the radial direction) of each turn portion 11n, is not particularly limited. However, considering the ability to transmit power of 1kW or more, preferably 5kW or more, in the high-frequency current frequency band of 79kHz to 90kHz, the radial width of the turn portion 11n may be 2mm to 20mm, 2mm to 16mm, 2mm to 12mm, or 2mm to 8mm.

[0077] The line width of the second planar coil element 12 (conductor 12E), that is, the radial width (width in the radial direction) of each turn portion 12n, is not particularly limited. However, the line width of each turn portion 12n of the second planar coil element 12 is determined such that, when viewed in the axial direction, each gap between the multiple turn portions 121 to 123 of the second planar coil element 12 overlaps with one of the gaps between the multiple turn portions 111 to 116 of the first planar coil element 11.

[0078] (Magnetic shielding member) The magnetic shielding member 20 is provided to suppress magnetic transmission and / or leakage magnetic fields. The magnetic shielding member 20 is a sheet-like member separate from the first planar coil element 11, the second planar coil element 12, and the holder 30. The fact that the magnetic shielding member 20 is separate from the first planar coil element 11, the second planar coil element 12, and the holder 30 means that the magnetic shielding member 20 is not integrated with these first planar coil element 11, the second planar coil element 12, and the holder 30. However, the magnetic shielding member 20 and the holder 30 may be joined via an adhesive layer or the like. The magnetic shielding member 20 is formed to be large enough to encompass the first planar coil element 11 and the second planar coil element 12 in a planar view. The magnetic shielding member 20 overlaps with the first planar coil element 11, the second planar coil element 12, and the holder 30, and is in direct contact with a part of the holder 30 (the second interlayer portion 32 described later).

[0079] In this embodiment, the magnetic shielding member 20 is magnetic and contains or is made of a magnetic material. In the coil component 5, a magnetic field is generated when current is supplied to the first planar coil element 11 and the second planar coil element 12. The magnetic field generated in such a coil component 5 is generated to spread in all directions with respect to the respective central axes C1 and C2 of the first planar coil element 11 and the second planar coil element 12. In this case, because the magnetic shielding member 20 is magnetic, it can orient the spreading magnetic flux lines toward the respective central axes C1 and C2. Furthermore, the coil component 5 can be installed on a moving body, but in this case, if the magnetic field generated in the coil component 5 flows toward other moving body components, it may adversely affect the moving body components. In such cases, the magnetic shielding member 20 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0080] The magnetic shielding member 20 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the magnetic shielding member 20 includes ferrite, preferably soft ferrite. In this embodiment, the magnetic shielding member 20 includes plate-shaped ferrite. More specifically, the magnetic shielding member 20 is constructed by arranging a plurality of plate-shaped ferrites in a sheet-like manner.

[0081] The relative permeability of the magnetic shielding member 20 may be 500 or more, or 1000 or more. The relative permeability of the magnetic shielding member 20 may be 500 or more and 3000 or less, or 1000 or more and 3000 or less. In this specification, the relative permeability is the value measured at a frequency of 85 kHz and an ambient temperature of 23 degrees Celsius.

[0082] (holding body) As described above, the holder 30 functions to maintain the gap between the first planar coil element 11 and the second planar coil element 12, as well as the gap between the second planar coil element 12 and the magnetic shielding member 20. In this embodiment, the holder 30 also has the function of integrating the first planar coil element 11 and the second planar coil element 12. Specifically, as shown in Figure 3, the holder 30 includes a first interlayer portion 31 disposed between the first planar coil element 11 and the second planar coil element 12, and a second interlayer portion 32 disposed between the second planar coil element 12 and the magnetic shielding member 20.

[0083] In this embodiment, the first interlayer portion 31 is joined to the first planar coil element 11 and the second planar coil element 12, and the second interlayer portion 32 is joined to the second planar coil element 12. As a result, the first planar coil element 11, the second planar coil element 12 and the holder 30 are integrated. Specifically, the first interlayer portion 31 fills the gap between the opposing turn portions 11n and 12n in the first planar coil element 11 and the second planar coil element 12, from the innermost turn portions 111 and 121 to the outermost turn portions 116 and 123. The second interlayer portion 32 fills the gap between all the turn portions 121 to 123 in the second planar coil element 12, from the innermost turn portion 121 to the outermost turn portion 123, and the portion of the magnetic shielding member 20 facing them.

[0084] In the illustrated example, the first interlayer portion 31 further fills the gaps between the multiple turn portions 111 to 116 of the first planar coil element 11. In the illustrated example, the second interlayer portion 32 further fills the gaps between the multiple turn portions 121 to 123 of the second planar coil element 12.

[0085] Furthermore, the holder 30 in this embodiment further includes an outer peripheral frame portion 33 located on the outer peripheral side of the first interlayer portion 31 and the second interlayer portion 32, and an inner peripheral core portion 34 located on the inner peripheral side of the first interlayer portion 31 and the second interlayer portion 32. The first interlayer portion 31 and the second interlayer portion 32 are connected to the outer peripheral frame portion 33 and also to the inner peripheral core portion 34. As a result, the first interlayer portion 31, the second interlayer portion 32, the outer peripheral frame portion 33, and the inner peripheral core portion 34 are formed as a single integrated unit.

[0086] Furthermore, the holder 30 may function with the first interlayer portion 31 solely for the purpose of maintaining the gap between the first planar coil element 11 and the second planar coil element 12, and the second interlayer portion 32 solely for the purpose of maintaining the gap between the second planar coil element 12 and the magnetic shielding member 20. In this case, it goes without saying that the first interlayer portion 31 does not need to be joined to the first planar coil element 11 and the second planar coil element 12, and the second interlayer portion 32 does not need to be joined to the second planar coil element 12. Also, the holder 30 does not need to include the outer peripheral frame portion 33 and the inner peripheral core portion 34.

[0087] The holder 30 is insulating and contains a resin. The holder 30 may be formed from, for example, an insulating resin. The resin contained in the holder 30 is not particularly limited as long as it is nonmagnetic and insulating. The holder 30 may contain, for example, polyethylene or polypropylene, or be formed from polyethylene or polypropylene. Furthermore, the holder 30 may contain, for example, fiber-reinforced plastic, or be formed from fiber-reinforced plastic. More specifically, the holder 30 may contain, or be formed from glass fiber-reinforced polyamide. Note that insulating means that the volume resistivity is 10 10 This means it is greater than or equal to Ω·m.

[0088] (Magnetic wall) The magnetic wall portion 40 extends in the axial direction, as shown in Figure 3. Also, as can be seen from Figures 2 and 3, when viewed in the axial direction, the magnetic wall portion 40 extends along the gap between the multiple turns 111 to 116 of the first planar coil element 11. In the illustrated example, the magnetic wall portion 40 has a spiral shape and, when viewed in the axial direction, overlaps with the gap between the multiple turns 111 to 116 of the first planar coil element 11.

[0089] The magnetic wall portion 40 is magnetic, and its performance is improved by suppressing eddy current losses and leakage flux, and by increasing the coupling coefficient. The relative permeability of the magnetic wall portion 40 is preferably 2.0 or higher, and may be between 2.0 and 20.0. The relative permeability of the magnetic wall portion 40 is more preferably 5.0 or higher, and may be between 5.0 and 20.0. The relative permeability of the magnetic wall portion 40 is not particularly limited, but if it is too high, the flexibility and strength of the magnetic wall portion 40 may be undesirably impaired. Therefore, the relative permeability of the magnetic wall portion 40 may be 200 or less.

[0090] In the example shown in Figure 3, the magnetic wall portion 40 is positioned opposite the second surface 11b of the first planar coil element 11. In the illustrated example, the magnetic wall portion 40 is positioned on the same plane as the second surface 11b. The height of the magnetic wall portion 40 (dimension along the axial direction) is not particularly limited, but may be 0.5 mm or more, or 1.0 mm or more.

[0091] In this embodiment, the magnetic wall portion 40 includes, for example, a retaining material containing resin and a plurality or countless magnetic particles composed of a magnetic material. The magnetic particles are held by the retaining material. The retaining material is insulating, and more specifically, non-magnetic and insulating. The retaining material is not particularly limited, but may include, for example, polyethylene or polypropylene, or be formed from polyethylene or polypropylene. The retaining material may also include, for example, fiber-reinforced plastic, or be formed from fiber-reinforced plastic. More specifically, the retaining material may include, or be formed from glass fiber-reinforced polyamide.

[0092] The magnetic particles may be formed from one or more of the following: ferrite, particularly soft magnetic materials; nanocrystalline magnetic materials; silicon steel; electromagnetic soft iron; and amorphous metals.

[0093] (Connection terminals) As shown in Figures 2 and 4, the first connection terminal 51 is connected to the radially outer end of the turn portion 116 in the first planar coil element 11. The second connection terminal 52 is connected to the radially outer end of the turn portion 123 in the second planar coil element 12. The first connection terminal 51 and the second connection terminal 52 can be used, for example, when connecting to a high-frequency current supply unit 1A or a conversion unit 2A. The connection between the first connection terminal 51 and the turn portion 116 and the connection between the second connection terminal 52 and the turn portion 123 may be performed by ultrasonic bonding. However, the connection method is not limited, and for example, a connection using a conductive adhesive may be employed.

[0094] <Variation> It is possible to make various modifications to the embodiment described above. Hereinafter, modifications of this embodiment will be described with reference to Figures 5 to 15.

[0095] For example, the magnetic wall portion 40 may extend axially from one side of the first planar coil element 11 to the other, passing through the gaps between the multiple turns 111 to 116 of the first planar coil element 11. In this case, the holder 30 may have a slit 36 ​​formed therein to receive the magnetic wall portion 40.

[0096] Furthermore, as shown in Figures 6 to 8, for example, the second planar coil element 12 may have elongated holes 12h that extend along the multiple turns 121 to 123 of the second planar coil element 12. In this case, more current can be passed through the second planar coil element 12 due to the skin effect. In the illustrated example, the elongated holes 12h extend along the spiral shape of the second planar coil element 12.

[0097] As can be seen from Figures 6 and 8, when an elongated hole 12h is formed in the second planar coil element 12, the elongated hole 12h may overlap with any of the gaps between the multiple turns 111 to 116 of the first planar coil element 11 when viewed in the axial direction. In this case, as shown in Figure 8, the magnetic material wall 40 may extend into the elongated hole 12h of the second planar coil element 12.

[0098] Furthermore, as shown in Figures 9 to 11, the first planar coil element 11 may be positioned opposite the magnetic shielding member 20. In other words, the first planar coil element 11 may be positioned between the second planar coil element 12 and the magnetic shielding member 20. In this case, the fourth surface 12b of the second planar coil element 12 forms the front surface 10b of the coil 10. Also, the second surface 11b of the first planar coil element 11 forms the back surface 10a of the coil 10. In this case, the magnetic material wall portion 40 may extend along the gap between the multiple turn portions 121 to 123 of the second planar coil element 12 when viewed in the axial direction. In the example shown in Figures 9 and 11, the magnetic material wall portion 40 overlaps with the gap between the multiple turn portions 121 to 123 of the second planar coil element 12 when viewed in the axial direction. The magnetic material wall portion 40 may be positioned opposite the fourth surface 12b of the second planar coil element 12, as shown in Figure 9. In the example shown in Figure 9, the magnetic wall portion 40 is located on the same plane as the fourth surface 12b. Alternatively, as shown in Figure 11, the magnetic wall portion 40 may extend axially from one side of the second planar coil element 12 to the other, passing through the gaps between the multiple turns 121 to 123 of the second planar coil element 12.

[0099] Furthermore, when the first planar coil element 11 is positioned opposite the magnetic shielding member 20, the second planar coil element 12 may have elongated holes 12h extending along a plurality of turns 121 to 123 of the second planar coil element 12, as shown in Figures 12 to 15. In this case, the coil component 5 may further include additional magnetic wall portions 45. The additional magnetic wall portions 45 extend along the axial direction. Also, the additional magnetic wall portions 45 extend along the elongated holes 12h when viewed in the axial direction. In the examples shown in Figures 12 to 15, the additional magnetic wall portions 45 overlap with the elongated holes 12h when viewed in the axial direction. The additional magnetic wall portions 45 may be positioned opposite the fourth surface 12b of the second planar coil element 12, as shown in Figures 12 to 14. In the examples shown in Figures 12 and 13, the additional magnetic wall portions 45 are positioned on the same plane as the fourth surface 12b. Alternatively, as shown in Figure 15, the additional magnetic wall portion 45 may extend axially from one side to the other of the second planar coil element 12 through elongated holes 12h formed in the multiple turns 121 to 123 of the second planar coil element 12. In this case, the holder 30 may have a slit 37 for receiving the additional magnetic wall portion 45.

[0100] <Applications of coil components> The coil component 5 according to this embodiment can be used as a power transmission coil in the power transmission device 1 of the wireless power transmission system S described above, and can also be used as a power receiving coil in the power receiving device 2.

[0101] When a coil component 5 is used as a power transmission coil, the first connection terminal 51 and the second connection terminal 52 are connected to a high-frequency current supply unit 1A or an AC power source as shown in Figure 1. When a high-frequency current is supplied to the coil component 5, the current can be passed from the first connection terminal 51 to the planar coil element 11, and then from the second connection terminal 52 to the high-frequency current supply unit 1A or the AC power source. Alternatively, the current can be passed from the second connection terminal 52 to the planar coil element 11, and then from the first connection terminal 51 to the high-frequency current supply unit 1A or the AC power source. This makes it possible to generate a magnetic field including magnetic field lines along the central axis C of the planar coil element 11.

[0102] On the other hand, when using the coil component 5 as the power receiving coil, a high-frequency current can be generated in the planar coil element 11 by receiving or generating a magnetic field including magnetic field lines that passes inside the planar coil element 11. This high-frequency current can then be supplied to an external device from the first connection terminal 51 or the second connection terminal 52.

[0103] Furthermore, the coil component 5 can also be used in transformers, antennas, and the like. For example, when the coil component 5 functions as the primary coil in a transformer, the first connection terminal 51 and the second connection terminal 52 are connected to an AC power source. By supplying a high-frequency current, magnetic flux can be supplied to the iron core from the central side of the planar coil element 11.

[0104] <Performance evaluation simulation of coil component 5> The following describes the simulations performed to evaluate the performance of coil components 5, 5', 5'', 5''', and 5'''' in Examples 1-4 and Comparative Examples 1-6. The simulations were performed using Femtet®, a registered trademark of Murata Software Corporation.

[0105] The common conditions in the simulations for Examples 1-4 and Comparative Examples 1-6 are as follows: The supplied high-frequency current is 40A, and the frequency is 85KHz. The first planar coil element 11 and the second planar coil elements 12, 12', 12'' are made of copper. The gap between the first planar coil element 11 and the second planar coil elements 12, 12', 12'', 12'''' is 0.50 mm, and the gap between the coils 10, 10', 10'', 10'''' and the magnetic shielding member 20 is 1.0 mm. The relative permeability of the magnetic shielding member 20 is 3000. The magnetic material wall portion 40 is arranged on the same plane as the front surfaces 10b, 10b', 10b, 10b''' of the coils 10, 10', 10'', 10''''. The relative permeability of the magnetic material wall portion 40 is 5.0.

[0106] The common conditions in the simulations of Examples 1 to 4 are as follows: The first planar coil element 11 has 6 turns T1, and the second planar coil element 12 has 3 turns T2. The wire width of the first planar coil element 11 is 9 mm, and the wire width of the second planar coil element 12 is 22 mm. Viewed in the axial direction, the inner edge of turn portion 121 overlaps with the inner edge of turn portion 111. Also, viewed in the axial direction, the outer edge of turn portion 121 overlaps with the outer edge of turn portion 112. Also, viewed in the axial direction, the inner edge of turn portion 122 overlaps with the inner edge of turn portion 113. Also, viewed in the axial direction, the outer edge of turn portion 122 overlaps with the outer edge of turn portion 114. Also, viewed in the axial direction, the inner edge of turn portion 123 overlaps with the inner edge of turn portion 115. Also, viewed in the axial direction, the outer edge of turn portion 123 overlaps with the outer edge of turn portion 116.

[0107] The individual conditions for the simulations in Examples 1-4 and Comparative Examples 1-4 are as follows: <Example 1> In the coil component 5 of Example 1, the magnetic shielding member 20 is positioned opposite the second planar coil element 12, similar to the examples shown in Figures 2 to 4. The thickness of the first planar coil element 11 is 0.25 mm, and the thickness of the second planar coil element 12 is 0.5 mm. The magnetic material wall portion 40 extends along the gap between the multiple turn portions 111 to 116 of the first planar coil element 11 when viewed in the axial direction, and overlaps with the gap. <Example 2> In the coil component 5 of Embodiment 2, the magnetic shielding member 20 is positioned opposite the second planar coil element 12, similar to the examples shown in Figures 6 and 7. The second planar coil element 12 has an elongated hole 12h that extends along the spiral shape of the second planar coil element 12. The elongated hole 12h overlaps with the gaps between the turn portions 111 and 112, the gaps between the turn portions 113 and 114, and the gaps between the turn portions 115 and 116 when viewed in the axial direction. The radial width of the elongated hole 12h is 9 mm. The other configurations are the same as in Embodiment 1. <Example 3> In the coil component 5 of Example 3, the magnetic shielding member 20 is positioned opposite the first planar coil element 11, similar to the examples shown in Figures 9 and 10. The thickness of the first planar coil element 11 is 0.5 mm, and the thickness of the second planar coil element 12 is 0.25 mm. The magnetic material wall portion 40 is positioned opposite the fourth surface 12b of the second planar coil element 12. When viewed in the axial direction, the magnetic material wall portion 40 extends along the gap between the multiple turn portions 121 to 123 of the second planar coil element 12 and overlaps with the gap. The other configurations are the same as in Example 1. <Example 4> In the coil component 5 of Example 4, the magnetic shielding member 20 is positioned opposite the second planar coil element 12, similar to the examples shown in Figures 12 to 14. The thickness of the first planar coil element 11 is 0.25 mm, and the thickness of the second planar coil element 12 is 0.5 mm. The second planar coil element 12 has an elongated hole 12h that extends along the spiral shape of the second planar coil element 12. The elongated hole 12h overlaps with the gaps between the turns 111 and 112, the gaps between the turns 113 and 114, and the gaps between the turns 115 and 116 when viewed in the axial direction. The radial width of the elongated hole 12h is 9 mm. An additional magnetic wall portion 45 is positioned opposite the fourth surface 12b of the second planar coil element 12. The additional magnetic wall portion 45 extends along the elongated hole 12h and overlaps with the elongated hole 12h when viewed in the axial direction. The relative permeability of the additional magnetic wall portion 45 is 5.0. The other configurations are the same as in Example 3. <Comparative Example 1> In the conventional coil component 5' of Comparative Example 1, as shown in Figure 16, the magnetic shielding member 20 is positioned opposite the second planar coil element 12'. The first planar coil element 11' has four turns 111 to 114. The second planar coil element 12' also has four turns 121 to 124. That is, the number of turns T1 of the first planar coil element 11 and the number of turns T2 of the second planar coil element 12' are both 4. The wire width of both the first planar coil element 11' and the second planar coil element 12' is 14 mm. Viewed axially, both edges of the turn 121 overlap with both edges of the turn 111. Viewed axially, both edges of the turn 122 overlap with both edges of the turn 112. Viewed axially, both edges of the turn 123 overlap with both edges of the turn 113. Furthermore, when viewed in the axial direction, both edges of the turn portion 124 overlap with both edges of the turn portion 114. The other configurations are the same as in Embodiment 1. <Comparative Example 2> In the conventional coil component 5' of Comparative Example 2, the wire width of the first planar coil element 11' and the wire width of the second planar coil element 12' are both 10 mm. The other configurations are the same as in Comparative Example 1. <Comparative Example 3> In the conventional coil component 5' of Comparative Example 3, the wire width of both the first planar coil element 11' and the second planar coil element 12' is 8 mm. The other configurations are the same as in Comparative Example 1. <Comparative Example 4> In the conventional coil component 5'' of Comparative Example 4, as shown in Figure 17, the magnetic shielding member 20 is positioned opposite the second planar coil element 12''. The first planar coil element 11 has six turns 111 to 116. The second planar coil element 12'' also has six turns 121 to 126. That is, the number of turns T1 of the first planar coil element 11 and the number of turns T2 of the second planar coil element 12'' are both 6. The wire width of the second planar coil element 12'' is 9 mm. Viewed axially, both edges of the turn 121 overlap with both edges of the turn 111. Viewed axially, both edges of the turn 122 overlap with both edges of the turn 112. Viewed axially, both edges of the turn 123 overlap with both edges of the turn 113. Furthermore, when viewed in the axial direction, both edges of the turn portion 124 overlap with both edges of the turn portion 114. Also, when viewed in the axial direction, both edges of the turn portion 125 overlap with both edges of the turn portion 115. Also, when viewed in the axial direction, both edges of the turn portion 126 overlap with both edges of the turn portion 116. The other configurations are the same as in Embodiment 1. <Comparative Example 5> In the coil component 5'' of Comparative Example 5, as shown in Figure 18, the magnetic shielding member 20 is positioned opposite the second planar coil element 12'. The first planar coil element 11 has six turns 111 to 116. The second planar coil element 12' has four turns 121 to 124. That is, the number of turns T1 of the first planar coil element 11 is 6, and the number of turns T2 of the second planar coil element 12' is 4. The wire width of the second planar coil element 12' is 14 mm. Viewed in the axial direction, the gaps between the multiple turns 121 to 124 of the second planar coil element 12' do not overlap with any of the gaps between the multiple turns 111 to 116 of the first planar coil element 11. The other configurations are the same as in Example 1. <Comparative Example 6> In the coil component 5'''' of Comparative Example 6, as shown in Figure 19, the magnetic shielding member 20 is positioned opposite the first planar coil element 11. The thickness of the first planar coil element 11 is 0.5 mm, and the thickness of the second planar coil element 12 is 0.25 mm. The magnetic material wall portion 40 extends along the gap between the multiple turns 121 to 124 of the second planar coil element 12' when viewed in the axial direction. The magnetic material wall portion 40 extends along the gap between the multiple turns 121 to 124 of the second planar coil element 12' when viewed in the axial direction, and overlaps with the gap. The other configurations are the same as in Comparative Example 5.

[0108] Figures 20 and 21 show the simulation results. As can be seen from Figures 20 and 21, even if the number of turns T2 of the second planar coil element 12 is less than the number of turns T1 of the first planar coil element 11, if each gap between the multiple turns 121 to 123 of the second planar coil element 12 overlaps with any of the gaps between the multiple turns 111 to 116 of the first planar coil element 11, the Q value of the coil component 5 does not decrease significantly compared to the coil components 5' of Comparative Examples 2 and 3, which have a conventional coil 10' with a similar line width and number of turns of the first planar coil element 11.

[0109] The coil component 5 according to the embodiment and its modifications described above comprises a coil 10 including a first planar coil element 11 and a second planar coil element 12. The first planar coil element 11 and the second planar coil element 12 each have a spiral shape with a plurality of turns 111-116 and 121-123. The first planar coil element 11 and the second planar coil element 12 are arranged facing each other in the axial direction extending along the central axes C1 and C2 of this spiral shape. The first planar coil element 11 and the second planar coil element 12 are connected in series with each other. The number of turns T2 of the second planar coil element 12 is less than the number of turns T1 of the first planar coil element 11. Also, in the axial direction, at least one of the plurality of turns 121-123 of the second planar coil element 12 overlaps with two or more of the plurality of turns 111-116 of the first planar coil element 11. Furthermore, when viewed in the axial direction, each gap between the multiple turns 121 to 123 of the second planar coil element 12 overlaps with one of the gaps between the multiple turns 111 to 116 of the first planar coil element 111. With such a coil component 5, the handling of the second planar coil element 12 can be improved, and the manufacturing efficiency of the coil component can be improved. In addition, compared to a conventional coil component 5' equipped with a coil 10' having a similar wire width and a similar number of turns in the first planar coil element 11, there is a lower risk of a significant decrease in the Q value of the coil component 5.

[0110] In one embodiment and a modified version thereof, the number of turns T1 of the first planar coil element 11 is twice the number of turns T2 of the second planar coil element 12. Viewed in the axial direction, each turn portion 121, 122, and 123 of the second planar coil element 12 overlaps with the two turn portions 111, 112, 123, 124, and 125, 126 of the first planar coil element 11. Such a coil component 5 is easy to design.

[0111] In one embodiment and a modified version thereof, in the coil component 5, when viewed in the axial direction, the inner edges of each turn portion 121, 122, and 123 of the second planar coil element 12 overlap with the inner edges of any of the turn portions 111, 113, and 114 of the first planar coil element 11. Also, the outer edges of each turn portion 121, 122, and 123 of the second planar coil element 12 overlap with the outer edges of any of the turn portions 112, 114, and 116 of the first planar coil element.

[0112] In the modified coil component 5, elongated holes 12h are formed in multiple turn portions 121 to 123 of the second planar coil element 12, extending along the turn portions 121 to 123. This allows more current to flow through the second planar coil element 12.

[0113] In the modified coil component 5, the elongated hole 12h extends along the spiral shape of the second planar coil element 12.

[0114] In the modified coil component 5, when viewed in the axial direction, the elongated hole 12h overlaps with one of the gaps between the multiple turn portions 111 to 116 of the first planar coil element 11.

[0115] In one embodiment and a modified version thereof, the thickness of the second planar coil element 12 is 0.15 mm or more and 0.35 mm or less. When the thickness of the second planar coil element 12 is this small, the handling of the second planar coil element 12 is significantly improved by reducing the number of turns T2 of the second planar coil element 12.

[0116] In one embodiment and its modified form, the coil component 5 further comprises a magnetic shielding member 20 positioned opposite the second planar coil element 12. In this case, the performance of the coil component 5 can be improved.

[0117] In embodiments and modifications in which the second planar coil element 12 is positioned opposite the magnetic shielding member 20, the coil component 5 further comprises a magnetic wall portion 40 that extends along the axial direction and along the gaps between the plurality of turns 111 to 116 of the first planar coil element 11 when viewed in the axial direction. The magnetic wall portion 40 is positioned opposite the second surface 11b of the first planar coil element 11, which is opposite to the first surface 11a that faces the second planar coil element 12. In this case, the performance of the coil component 5 can be further improved.

[0118] In a modified example in which the second planar coil element 12 is positioned opposite the magnetic shielding member 20, the coil component 5 further comprises a magnetic wall portion 40 that extends along the axial direction and along the gap between the multiple turns 111 to 116 of the first planar coil element 11 when viewed in the axial direction. The magnetic wall portion 40 extends along the axial direction from one side of the first planar coil element 11 to the other, passing through the gap between the multiple turns 111 to 116 of the first planar coil element 11. In this case, the performance of the coil component 5 can be further improved.

[0119] The modified coil component 5 further includes a magnetic shielding member 20 positioned opposite the first planar coil element 11. In this case as well, the performance of the coil component 5 can be improved.

[0120] In a modified example in which the first planar coil element 11 is positioned opposite the magnetic shielding member 20, the coil component 5 further comprises a magnetic wall portion 40 that extends along the axial direction and along the gaps between the multiple turn portions 121 to 123 of the second planar coil element 12 when viewed in the axial direction. The magnetic wall portion 40 is positioned opposite the fourth surface 12b of the second planar coil element 12, which is opposite to the third surface 12a that faces the first planar coil element 11. In this case, the performance of the coil component 5 can be further improved.

[0121] In a modified example in which the first planar coil element 11 is positioned opposite the magnetic shielding member 20, the coil component 5 further comprises a magnetic wall portion 40 that extends axially and along the gap between the multiple turns 121 to 123 of the second planar coil element 12 when viewed in the axial direction. The magnetic wall portion 40 extends axially from one side of the second planar coil element 12 to the other, passing through the gap between the multiple turns 121 to 123 of the second planar coil element 12. In this case, the performance of the coil component 5 can be further improved.

[0122] In a modified configuration in which the first planar coil element 11 is positioned opposite the magnetic shielding member 20, elongated holes 12h extending along the turns 121 to 123 are formed in the multiple turns 121 to 123 of the second planar coil element 12. The coil component 5 also further comprises an additional magnetic wall portion 45. The additional magnetic wall portion 45 extends along the axial direction and, when viewed in the axial direction, along the elongated holes 12h. The additional magnetic wall portion 45 is positioned opposite the fourth surface 12b of the second planar coil element 12, which is opposite to the third surface 12a facing the first planar coil element 11. In this case, the performance of the coil component 5 can be further improved.

[0123] In a modified configuration in which the first planar coil element 11 is positioned opposite the magnetic shielding member 20, the coil component 5 has elongated holes 12h formed in a plurality of turns 121 to 123 of the second planar coil element 12, extending along the turns 121 to 123. The coil component 5 also further comprises an additional magnetic wall portion 45. The additional magnetic wall portion 45 extends axially and also extends along the elongated holes 12h when viewed in the axial direction. The additional magnetic wall portion 45 extends axially from one side to the other of the second planar coil element 12 through the elongated holes 12h formed in the plurality of turns 121 to 123 of the second planar coil element 12. In this case, the performance of the coil component 5 can be further improved.

[0124] In addition, while several modifications of the above-described embodiments have been explained, it is naturally possible to combine and apply multiple modifications as appropriate. [Explanation of Symbols]

[0125] S...Power transmission system 1... Power transmission equipment 1A…High-frequency current supply unit 2... Power receiving device 2A...Conversion section 5, 5', 5'', 5''', 5''''... coil parts 10, 10', 10''... coil 11, 11'... First planar coil element 11a…First page 11b…Second side 11E... Conductor 12, 12', 12''... Second planar coil element 12a...Side 3 12b...Side 4 12h…long hole 12E...Conductor 20…Magnetic shielding material 30...Holding body 40...Magnetic wall part 45... Additional magnetic wall section 51…First connection terminal 52...Second connection terminal C1…First central axis line C2…Second central axis line

Claims

1. A coil component for a wireless power transmission system, The coil comprises a first planar coil element and a second planar coil element, each having a spiral shape with multiple turns, and arranged opposite to each other in the axial direction extending along the central axis of the spiral shape, and connected in series with each other. The number of turns of the second planar coil element is less than the number of turns of the first planar coil element. Viewed in the axial direction, at least one of the plurality of turns of the second planar coil element overlaps with two or more of the plurality of turns of the first planar coil element. A coil component in which, when viewed in the axial direction, each gap between the plurality of turns of the second planar coil element overlaps with any of the gaps between the plurality of turns of the first planar coil element.

2. The number of turns of the first planar coil element is twice the number of turns of the second planar coil element. The coil component according to claim 1, wherein, when viewed in the axial direction, each turn portion of the second planar coil element overlaps with the two turn portions of the first planar coil element.

3. The coil component according to claim 1, wherein, when viewed in the axial direction, the inner edge of each turn portion of the second planar coil element overlaps with the inner edge of any turn portion of the first planar coil element, and the outer edge of each turn portion of the second planar coil element overlaps with the outer edge of any turn portion of the first planar coil element.

4. The coil component according to claim 1, wherein the plurality of turns of the second planar coil element have elongated holes extending along the turns.

5. The coil component according to claim 4, wherein the elongated hole extends along the spiral shape of the second planar coil element.

6. The coil component according to claim 4, wherein, when viewed in the axial direction, the elongated hole overlaps with any of the gaps between the plurality of turned portions of the first planar coil element.

7. The coil component according to claim 1, wherein the thickness of the second planar coil element is 0.15 mm or more and 0.35 mm or less.

8. The coil component according to claim 1, further comprising a magnetic shielding member disposed opposite to the second planar coil element.

9. The magnetic material wall portion further extends along the axial direction and along the gaps between the multiple turns of the first planar coil element when viewed in the axial direction, The coil component according to claim 8, wherein the magnetic material wall portion is arranged facing the second surface of the first planar coil element, which is opposite to the first surface facing the second planar coil element.

10. The magnetic material wall portion further extends along the axial direction and along the gaps between the multiple turns of the first planar coil element when viewed in the axial direction, The coil component according to claim 8, wherein the magnetic wall portion extends along the axial direction from one side of the first planar coil element to the other side, passing through the gaps between the plurality of turns of the first planar coil element.

11. The coil component according to claim 1, further comprising a magnetic shielding member disposed opposite to the first planar coil element.

12. The magnetic material wall portion further extends along the axial direction and along the gaps between the multiple turns of the second planar coil element when viewed in the axial direction, The coil component according to claim 11, wherein the magnetic material wall portion is arranged facing the fourth surface of the second planar coil element, which is opposite to the third surface facing the first planar coil element.

13. The magnetic material wall portion further extends along the axial direction and along the gaps between the multiple turns of the second planar coil element when viewed in the axial direction, The coil component according to claim 11, wherein the magnetic wall portion extends along the axial direction from one side of the second planar coil element to the other side, passing through the gaps between the plurality of turns of the second planar coil element.

14. Elongated holes extending along the turns are formed in the plurality of turns of the second planar coil element. The coil component further comprises an additional magnetic wall portion, The additional magnetic wall portion extends along the axial direction and extends along the elongated hole when viewed in the axial direction. The coil component according to claim 11, wherein the additional magnetic wall portion is arranged facing the fourth surface of the second planar coil element, which is opposite to the third surface facing the first planar coil element.

15. Elongated holes extending along the turns are formed in the plurality of turns of the second planar coil element. The coil component further comprises an additional magnetic wall portion, The additional magnetic wall portion extends along the axial direction and extends along the elongated hole when viewed in the axial direction. The coil component according to claim 11, wherein the additional magnetic wall portion extends along the axial direction from one side of the second planar coil element to the other side, through the elongated holes formed in a plurality of turns of the second planar coil element.

16. A power transmission device comprising the coil component described in claim 1.

17. A power receiving device comprising the coil component described in claim 1.

18. A mobile body comprising the power receiving device described in claim 17.

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

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