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

Abstract

To provide a coil component in which suitable coil performance can be secured while suppressing the weight or even under a condition with limited weight.SOLUTION: A coil component 10 includes a first coil 111 and a second coil 112 overlapping with the first coil 111. The specific gravity of the first coil 111 is different from that of the second coil 112.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] In recent years, wireless power transmission systems that transmit power contactlessly have become widespread. Demand for wireless power transmission systems that can transmit large amounts of power is expected to increase in the future.

[0003] When transmitting large amounts of power wirelessly, a large high-frequency current flows through a resonant circuit that includes a coil. This increases the amount of heat generated by the coil. The amount of heat generated by the coil increases due to, for example, the skin effect.

[0004] The skin effect increases AC resistance and consumes power due to heat generation, which can also cause a decrease in transmission efficiency.

[0005] When a litz wire is used as a coil, the skin effect is suppressed. However, since a litz wire is formed by twisting together a large number of enameled wires, the manufacturing cost is high and the manufacturing process is time-consuming. On the other hand, a technique using a spiral, plate-shaped planar coil is also known (see Patent Document 1). Such a planar coil improves manufacturing efficiency regardless of the coil size. Therefore, planar coils are suitable for high-power systems where the coil size can be large.

[0006] A suitable material for the Litz wire coil and the planar coil is copper, which has high electrical conductivity and can reduce loss. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-27112 Summary of the Invention [Problem to be solved by the invention]

[0008] When transmitting a large amount of power in a wireless power transmission system, the size of the coil may become large and the overall length may become long.

[0009] However, using copper as the material for large coils increases weight and costs. For example, when transmitting large amounts of power wirelessly to electric vehicles, it is particularly important to reduce the weight of the coil on the vehicle side. Furthermore, it is undesirable for the installation of a coil to excessively increase the vehicle price.

[0010] The present disclosure has been made in consideration of the above circumstances, and its objective is to provide a coil component, a power transmitting device, a power receiving device, and a power transfer system that can ensure suitable coil performance while suppressing weight or even under conditions where weight is restricted. [Means for solving the problem]

[0011] A coil component according to one embodiment includes a first coil and a second coil overlapped with the first coil, and the specific gravity of the first coil is different from the specific gravity of the second coil.

[0012] The second coil may have a specific gravity less than the specific gravity of the first coil, and the second coil may have a conductivity less than the conductivity of the first coil.

[0013] The coil component may further include a magnetic member containing a magnetic substance, and the magnetic member, the second coil, and the first coil may be arranged in this order.

[0014] The magnetic material may be ferrite.

[0015] The first coil may be formed of copper or a copper alloy, and the second coil may be formed of aluminum or an aluminum alloy.

[0016] The first coil may overlap the second coil with a gap therebetween, the first coil may have a first end and a second end, the second coil may have a first end and a second end, one of the first end and the second end of the first coil may be electrically connected to one of the first end and the second end of the second coil, and the other of the first end and the second end of the first coil may be electrically connected to the other of the first end and the second end of the second coil.

[0017] The first coil may overlap the second coil via an insulating layer disposed in the gap.

[0018] The first coil may have a spiral shape, the second coil may have a spiral shape, and the first end serving as an inner peripheral end of the first coil may be electrically connected to the first end serving as an inner peripheral end of the second coil, the second end serving as an outer peripheral end of the first coil may be electrically connected to the second end serving as an outer peripheral end of the second coil, and the first end of the first coil may be connected to the first end of the second coil through a hole provided in the insulating layer.

[0019] The first coil may have a spiral shape, the second coil may have a spiral shape with the same pattern as the first coil, and the first coil and the second coil may overlap and contact each other so that their spiral shapes match.

[0020] The first coil may be plate-shaped, and the second coil may be plate-shaped.

[0021] Moreover, a power transmitting device according to one embodiment includes the coil component. A power receiving device according to one embodiment includes the coil component. Moreover, a power transfer system according to one embodiment includes a power transmitting device and a power receiving device, and at least one of the power transmitting device and the power receiving device includes the coil component. [Effects of the Invention]

[0022] According to the present disclosure, it is possible to ensure suitable coil performance while suppressing weight or even under conditions where weight is restricted. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram schematically illustrating a wireless power transmission system to which a coil component according to a first embodiment is applied. [Figure 2] FIG. 1 is a plan view of a coil component according to a first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the coil component taken along line III-III in FIG. 2. [Figure 4] 4 is a cross-sectional view of the coil component taken along line IV-IV in FIG. 2. [Figure 5] FIG. 10 is a cross-sectional view of a coil component according to a second embodiment. [Figure 6] 6 is a cross-sectional view of a coil component according to a second embodiment taken in a direction different from that of FIG. 5. [Figure 7] FIG. 10 is a cross-sectional view of a coil component according to a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a coil component according to a fourth embodiment. [Figure 9] FIG. 10 is a graph showing a simulation result regarding performance evaluation of the coil component according to the embodiment. [Figure 10] 10A and 10B are graphs showing simulation results relating to performance evaluation of coil components according to the embodiment and modifications. [Figure 11] FIG. 10 is a graph showing a simulation result regarding performance evaluation of the coil component according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Each embodiment will be described below with reference to the drawings.

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

[0026] In addition, in this specification, the term "sheet surface (plate surface, film surface)" refers to a surface that coincides with the planar direction (face direction) of the target sheet-like member when the target sheet-like member is viewed overall and in a global perspective. Furthermore, in this specification, the normal direction of the sheet-like member refers to the normal direction to the sheet surface of the target sheet-like member.

[0027] First Embodiment 1 schematically shows a wireless power transmission system S to which a coil device 10 according to the first embodiment is applied. First, the wireless power transmission system S (hereinafter abbreviated as power transmission system S) will be described with reference to FIG.

[0028] (Wireless power transmission system) The power transmission system S includes a power transmitting device 1 and a power receiving device 2. The power transmitting device 1 includes a coil component 10 and a high-frequency current supply unit 1A. The coil component 10 in the power transmitting device 1 functions as a power transmitting coil. The high-frequency current supply unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil.

[0029] The power receiving device 2 includes a coil component 10 and a conversion unit 2A. The coil component 10 in the power receiving device 2 functions as a power receiving coil. The conversion unit 2A shapes the high-frequency current generated in the coil component 10. The conversion unit 2A includes a rectifier circuit that converts the high-frequency current into a direct current.

[0030] In this embodiment, each of the power transmitting device 1 and the power receiving device 2 includes a coil component 10. However, the coil component 10 may be used in only one of the power transmitting device 1 and the power receiving device 2, and a different type of coil component may be used in the other.

[0031] When transmitting power wirelessly (contactlessly) from the power transmitting device 1 to the power receiving device 2, the power transmitting device 1 supplies a high-frequency current of a predetermined frequency from the high-frequency current supply unit 1A to the coil component 10 serving as a power transmitting coil. At this time, a magnetic field is generated in the coil component 10 due to electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil component 10 serving as a power receiving coil in the power receiving device 2. 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).

[0032] The power transmission system S shown in FIG. 1 employs a magnetic resonance method as a power transmission method. However, the coil device 10 according to this embodiment may also be used in a power transmission system that employs an electromagnetic induction method. The power transmission system S is configured as a system that wirelessly transmits power to an electric vehicle. In this case, the power transmitting device 1 is installed on a road, in a parking lot, or the like. The power receiving device 2 is installed in the electric vehicle.

[0033] However, the use of the power transmission system S is not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to an aircraft such as a drone or a robot. The power transmission system S may also be used to transmit power to a submersible or an exploration robot in the sea. The use of the coil component 10 is not limited to wireless power transmission systems. For example, the coil component 10 may be used in a transformer, a DC-DC converter, an antenna, or the like.

[0034] (coil parts) Fig. 2 is a plan view of the coil device 10. Fig. 3 is a cross-sectional view of the coil device 10 taken along line III-III in Fig. 2. Fig. 4 is a cross-sectional view of the coil device 10 taken along line IV-IV in Fig. 2.

[0035] The coil device 10 has a first coil 111 and a second coil 112. The first coil 111 and the second coil 112 are stacked on top of each other. The coil device 10 shown in FIGS. 2 to 4 has the first coil 111, the second coil 112, a support member 20, a magnetic shield member 40 as a magnetic member, a first connection terminal 51, and a second connection terminal 52. The first coil 111, the second coil 112, and the magnetic shield member 40 are arranged on the support member 20.

[0036] In this embodiment, the second coil 112 is provided on a sheet-like base material layer 121. The first coil 111 is provided on the second coil 112 with an intermediate coating layer 131 interposed therebetween. A surface coating layer 141 is provided on the first coil 111. Note that the surface coating layer 141 is not shown in FIG. 2 for ease of explanation.

[0037] The base material layer 121, the intermediate coating layer 131, and the surface coating layer 141 each have insulating properties. The materials for forming the base material layer 121, the intermediate coating layer 131, and the surface coating layer 141 are not particularly limited, and may be a thermoplastic resin or a thermosetting resin. The coil component 10 may not have the support member 20 or the magnetic shield member 40. For example, the coil component 10 may be composed of the first coil 111, the second coil 112, the base material layer 121, the intermediate coating layer 131, and the surface coating layer 141. The base material layer 121, the intermediate coating layer 131, and the surface coating layer 141 may also be absent.

[0038] As shown in the figure, the first coil 111 and the second coil 112 may be planar coils. The second coil 112 is overlapped on the first coil 111 in the axial direction of the first coil 111. Here, the axial direction means a direction extending on the central axis of the coil or a direction parallel to the central axis.

[0039] As shown in the figures, the first coil 111 and the second coil 112 are stacked coaxially. That is, the first coil 111 and the second coil 112 are stacked so that their central axes are approximately aligned, preferably coincident. The symbol C shown in Figures 2 to 4 indicates a common central axis that passes through the center of the spiral shape of the first coil 111 and the center of the spiral shape of the second coil 112, which are arranged coaxially.

[0040] Both the first coil 111 and the second coil 112 have a spiral shape. More specifically, the second coil 112 has a spiral shape with the same pattern as the first coil 111. The first coil 111 and the second coil 112 overlap so that their spiral shapes match. Therefore, only the outline of the first coil 111 is shown in FIG. 2.

[0041] The first coil 111 includes a linear first conductor 111E. The first conductor 111E has a spiral shape and extends in a spiral shape. The first coil 111 is also plate-shaped. As shown in FIG. 3, the cross-sectional shape of the first coil 111 in a direction perpendicular to the winding direction of the spiral shape is rectangular. That is, the cross-sectional shape of the first conductor 111E in a direction perpendicular to the winding direction of the spiral shape is rectangular.

[0042] Similarly, the second coil 112 includes a linear second conductor 112E. This second conductor 112E has a spiral shape and extends in a spiral shape. The second coil 112 is also plate-shaped. As shown in FIG. 3, the cross-sectional shape of the second coil 112 in a direction perpendicular to the winding direction of the spiral shape is rectangular. That is, the cross-sectional shape of the second conductor 112E in a direction perpendicular to the winding direction of the spiral shape is rectangular.

[0043] The first conductor 111E of the first coil 111 has a bottom surface 111Ea facing the second coil 112, a first side surface 111Eb connected to the bottom surface 111Ea and facing the central axis C, a second side surface 111Ec connected to the bottom surface 111Ea and facing the side opposite the central axis C, and a top surface 111Ed facing the side opposite the second coil 112. The second conductor 112E of the second coil 112 has a bottom surface 112Ea facing the base layer 121, a first side surface 112Eb connected to the bottom surface 112Ea and facing the side opposite the central axis C, a second side surface 112Ec connected to the bottom surface 112Ea and facing the side opposite the central axis C, and a top surface 112Ed facing the side opposite the base layer 121.

[0044] When the first coil 111 and the second coil 112 described above overlap each other so that their spiral shapes match, the first conductor 111E and the second conductor 112E also overlap each other so that their spiral shapes match. In other words, the linear first conductor 111E and the linear second conductor 112E at least partially overlap each other. In other words, the linear first conductor 111E and the linear second conductor 112E extend in parallel at least partially. That is, the linear second conductor 112E extends along the linear first conductor 111E so as to at least partially overlap the linear first conductor 111E. Furthermore, when the first coil 111 and the second coil 112 are overlapped such that their spiral shapes are aligned, the bottom surface 111Ea of the first conductor 111E and the top surface 112Ed of the second conductor 112E at least partially face each other. In this embodiment, the widths of the first conductor 111E and the second conductor 112E are the same, but they may be different. For example, the width of the first conductor 111E may be smaller than the width of the second conductor 112E.

[0045] The illustrated first coil 111 is a planar coil, and the illustrated second coil 112 is a planar coil. A planar coil is a coil located on a certain plane. The linear conductor that forms the planar coil extends around a central axis on a certain plane, and gradually becomes positioned radially outward as it goes around. In other words, the linear conductor has a spiral shape. The axial direction of the planar coil is a direction perpendicular to the "certain plane" on which the conductor is located. In a planar coil, the conductors (wound portions of the conductors) are arranged with gaps in the radial direction. The radial direction is a direction perpendicular to the central axis of the planar coil. The radial outer side refers to the side away from the radial central axis. The radial inner side refers to the side closer to the radial central axis.

[0046] As shown in FIG. 2, in each of the coils 111, 112 (each of the conductors 111E, 112E), multiple radially arranged windings constituting a spiral shape are wound to form a rectangle, or in other words, they circle around. To be precise, the corners of the rectangle formed by the windings in FIG. 2 are curved. However, each of the coils 111, 112 (each of the conductors 111E, 112E) may also be wound so that each winding forms a circle. A spiral shape refers to a planar curved shape wound in a spiral shape. The planar curve referred to here also includes a planar pattern in which a portion extends linearly, as shown in the figure. In other words, a spiral shape is a shape that circles around a central axis C, gradually moving outward.

[0047] To explain the illustrated coil shape in more detail, in FIG. 2, the first coil 111 (first conductor 111E) has an inner circumferential end 111A as a first end and an outer circumferential end 111B as a second end. The first coil 111 (first conductor 111E) is formed in a shape that winds nine times from the inner circumferential end 111A to the outer circumferential end 111B. That is, the first coil 111 has nine windings connected together to form a spiral shape. The gap between adjacent windings is constant. More precisely, in the illustrated example, the outermost (ninth) winding extends straight after completing three-quarters of a turn. The width from the inner circumferential end 111A to the outer circumferential end 111B is constant. The size of the gap between adjacent winding portions of the first coil 111 may be different from the size of the gap between other winding portions. The size of the gap between adjacent winding portions may also be partially different. The width from the inner circumferential end 111A to the outer circumferential end 111B of the first coil 111 does not have to be constant.

[0048] Similarly, the second coil 112 (second conductor 112E) has an inner circumferential end 112A as a first end and an outer circumferential end 112B as a second end. The second coil 112 (second conductor 112E) is formed by winding nine times from the inner circumferential end 112A to the outer circumferential end 112B. That is, the second coil 112 has nine windings connected together to form a spiral shape. The gap between adjacent windings is constant. More precisely, the outermost ninth winding extends straight after completing three-quarters of a turn. The width from the inner circumferential end 112A to the outer circumferential end 112B is constant. The size of the gap between adjacent winding portions of second coil 112 may be different from the size of the gap between other winding portions. The size of the gap between adjacent winding portions may also be partially different. The width from inner circumferential end 112A to outer circumferential end 112B of second coil 112 does not have to be constant.

[0049] In this embodiment, as shown in FIG. 3, the inner peripheral end 111A of the first coil 111 is electrically connected to the inner peripheral end 112A of the second coil 112. As shown in FIG. 4, the outer peripheral end 111B of the first coil 111 is electrically connected to the outer peripheral end 112B of the second coil 112. The inner peripheral end 111A of the first coil 111 contacts the inner peripheral end 112A of the second coil 112 through a first through-hole 131A provided in the intermediate coating layer 131, which is an insulating layer, and they are connected to each other by ultrasonic welding or the like. Similarly, the outer peripheral end 111B of the first coil 111 contacts the outer peripheral end 112B of the second coil 112 through a second through-hole 131B provided in the intermediate coating layer 131, which is an insulating layer, and they are connected to each other by ultrasonic welding or the like.

[0050] As described above, the first coil 111 and the second coil 112 are electrically connected, so that the first coil 111 and the second coil 112 can integrally function as a coil. For example, in this embodiment, a current input to the inner peripheral end 111A of the first coil 111 can be simultaneously passed through the first coil 111 and the second coil 112, and then sent to the outside from the outer peripheral end 111B of the first coil 111. Note that being electrically connected may mean a state in which two members are electrically connected by being in direct contact with each other, or a state in which two members are electrically connected with another conductor interposed between them.

[0051] Here, the first connection terminal 51 is connected to the inner peripheral end 111A of the first coil 111. The second connection terminal 52 is connected to the outer peripheral end 111B of the first coil 111. More specifically, the first connection terminal 51 is connected to the inner peripheral end 111A of the first coil 111 through a first through-hole 141A provided in the surface coating layer 141. The second connection terminal 52 is connected to the outer peripheral end 111B of the first coil 111 through a second through-hole 141B provided in the surface coating layer 141. Referring also to FIG. 2 , the first connection terminal 51 extends on the surface coating layer 141 from the inner peripheral end 111A of the first coil 111 toward the outside of the support member 20. The first connection terminal 51 and the second connection terminal 52 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A.

[0052] Furthermore, the manner in which the first coil 111 and the second coil 112 are connected is not limited to the manner described in this embodiment. For example, the inner peripheral end 111A of the first coil 111 may be electrically connected to the outer peripheral end 112B of the second coil 112, and the outer peripheral end 111B of the first coil 111 may be electrically connected to the inner peripheral end 111A of the second coil 112. Alternatively, the inner peripheral end 111A of the first coil 111 may be electrically connected to the inner peripheral end 112A of the second coil 112, and the outer peripheral end 111B of the first coil 111 and the outer peripheral end 112B of the second coil 112 may not be electrically connected.

[0053] The first coil 111 is made of a conductive material, and in this embodiment is made of copper. The second coil 112 is made of a conductive material different from that of the first coil 111. More specifically, the second coil 112 is made of aluminum.

[0054] In this embodiment, the materials for the first coil 111 and the second coil 112 are selected so that the specific gravity of the conductive material for the first coil 111 is different from the specific gravity of the conductive material for the second coil 112. Specifically, the materials for the first coil 111 and the second coil 112 are selected so that the specific gravity of the second coil 112 is smaller than the specific gravity of the first coil 111.

[0055] In the present embodiment, the specific gravity of the second coil 112 is set lower than the specific gravity of the first coil 111 in order to reduce the weight of the coil device 10 or to ensure favorable coil performance even under weight constraints. In this case, for example, when a single coil made of copper is compared with the first coil 111 made of copper and the second coil 112 made of aluminum according to the present embodiment at the same volume, the coil made of copper according to the present embodiment is lighter. On the other hand, although the conductivity of aluminum is lower than that of copper, it may be able to fully satisfy the required specifications. Furthermore, when a single coil made of copper is compared with the first coil 111 made of copper and the second coil 112 made of aluminum according to the present embodiment at the same weight, the total volume of the first coil 111 and the second coil 112 according to the present embodiment is larger than that of a single coil made of copper alone. In this case, the coil performance, such as the Q value, obtained by the first coil 111 and the second coil 112 may be better than that of a single coil made of copper alone. Furthermore, even if the weight of the copper first coil 111 and aluminum second coil 112 in this embodiment is lighter than that of a single coil made of copper, the coil performance such as the Q value obtained by the first coil 111 and the second coil 112 may be better than that of a single coil made of copper only.

[0056] There are no particular limitations on the materials of the first coil 111 and the second coil 112. For example, the first coil 111 may be made of copper and the second coil 112 may be made of an aluminum alloy. Alternatively, the first coil 111 may be made of a copper alloy and the second coil 112 may be made of aluminum or an aluminum alloy.

[0057] In this embodiment, the first coil 111 is formed by punching a copper plate into a spiral shape. The thickness of the first coil 111, more precisely, the thickness of the first conductor 111E, may be, for example, 0.2 mm or more and 1.0 mm or less. The radius of the first coil 111, more precisely, the radius of the first conductor 111E (the distance from the central axis C to the farthest point in the radial direction) may be 200 mm or more. When transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit 1 kW or more, preferably 5 kW or more, of high-frequency current in the frequency range of 79 kHz to 90 kHz. In this case, the thickness of the first coil 111, more precisely, the thickness of the first conductor 111E, which is made of copper, is preferably 0.2 mm or more, although this depends on the thickness of the second coil 112. Note that if the thickness of the copper first coil 111 is too large, the weight increases and it is not desirable for in-vehicle installation. Therefore, the thickness of the first coil 111 may be, for example, 1.0 mm or less.

[0058] Similarly, the second coil 112 is formed by punching an aluminum plate into a spiral shape. The thickness of the second coil 112, more precisely, the thickness of the second conductor 112E, may be, for example, 0.2 mm or more and 1.0 mm or less. The radius of the second coil 112, more precisely, the radius of the second conductor 112E (the distance from the central axis C to the farthest point in the radial direction) may be 200 mm or more. As mentioned above, when transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit 1 kW or more, and preferably 5 kW or more, of high-frequency current in the frequency range of 79 kHz to 90 kHz. In this case, the thickness of the second coil 112 formed from aluminum, more precisely, the thickness of the second conductor 112E, is preferably 0.2 mm or more, although this depends on the thickness of the first coil 111.

[0059] 2, the symbol LD indicates the maximum length in the longitudinal direction of the first coil 111 and the second coil 112, which have a rectangular outline in a plan view. The symbol SD indicates the maximum length of the first coil 111 and the second coil 112 in a direction perpendicular to the longitudinal direction. For example, the maximum length LD and the maximum length SD may be 400 mm or more.

[0060] On the other hand, the first coil 111 and the second coil 112 can also be formed by etching a foil into a spiral shape. In this case, the first coil 111 and the second coil 112 can be formed into a complex spiral pattern. However, it takes time and effort to ensure that the first coil 111 and the second coil 112 have a thickness that allows for the transmission of high power. Therefore, punching is preferable from the viewpoint of manufacturing efficiency.

[0061] The support member 20 overlaps the first coil 111 and the second coil 112 in the axial direction and supports the first coil 111 and the second coil 112 via the magnetic shield member 40. In this embodiment, the support member 20 includes a bottom plate portion 22 that overlaps the first coil 111, the second coil 112, and the magnetic shield member 40, and a side plate portion 23 provided on the periphery of the bottom plate portion 22. The side plate portion 23 rises from the bottom plate portion 22. The end of the side plate portion 23 opposite the bottom plate portion 22 is open. The support member 20 is preferably covered with a cover member (not shown) to prevent the intrusion of moisture and foreign matter. The cover member is preferably made of an insulating material so as not to block the formation of a magnetic field, but may be made of a material other than metal. The bottom plate portion 22 is rectangular in plan view, but may be other shapes, such as circular. The support member 20 may also include a metal to block leakage magnetic fields. In this case, it is preferable that only the bottom plate portion 22 be made of metal in order to suppress the influence on power transmission.

[0062] The side plate portion 23 receives the first coil 111, the second coil 112, and the magnetic shield member 40 inside. This makes it easy to assemble the first coil 111, the second coil 112, and the magnetic shield member 40. It also makes it easy to handle the coil component 10. The support member 20 may be joined to the magnetic shield member 40 by, for example, an adhesive sheet. The first coil 111 and the second coil 112 may be joined to the magnetic shield member 40 via a base layer 121.

[0063] The magnetic shield member 40 is provided to suppress the transmission of magnetic field lines and / or leakage magnetic fields. The magnetic shield member 40 is formed to a size that encompasses the first coil 111 and the second coil 112 in a plan view and is in contact with the entire base layer 121. The magnetic shield member 40 in this embodiment includes a magnetic material. When the coil component 10 is installed in a vehicle, if the magnetic field generated by the coil component 10 on the power transmission side flows toward other vehicle components, it may adversely affect the vehicle components. Therefore, the magnetic shield member 40 is provided to suppress the transmission of magnetic field lines. Furthermore, the magnetic field generated by the coil component 10 spreads in all directions relative to the central axis C of the coil. In this case, the magnetic shield member 40 has magnetism, which allows the spreading magnetic flux lines to be directed toward the central axis C. As a result, the magnetic shield member 40 can suppress leakage magnetic fields that do not contribute to the generation of current. The magnetic shield member 40 preferably includes a soft magnetic material. More specifically, the magnetic shield member 40 includes ferrite, preferably soft ferrite.

[0064] (Coil component applications) The coil device 10 according to this embodiment can be used as a power transmitting coil in the power transmitting device 1 of the wireless power transmission system S, for example, as described above, and can be used as a power receiving coil in the power receiving device 2.

[0065] When the coil component 10 is used as a power transmission coil, the first connection terminal 51 and the second connection terminal 52 are connected to the high-frequency current supply unit 1A or an AC power supply as shown in FIG. 1 . When a high-frequency current is supplied to the coil component 10, the current can be passed from the first connection terminal 51 to the first coil 111 and the second coil 112 simultaneously, and then from the second connection terminal 52 to the high-frequency current supply unit 1A or the AC power supply. Alternatively, the current can be passed from the second connection terminal 52 to the first coil 111 and the second coil 112 simultaneously, and then from the first connection terminal 51 to the high-frequency current supply unit 1A or the AC power supply. This allows a magnetic field including magnetic field lines along the central axes of the first coil 111 and the second coil 112 to be generated.

[0066] On the other hand, when the coil device 10 is used as a power receiving coil, a high-frequency current can be generated that flows through the first coil 111 and the second coil 112 by receiving a magnetic field that includes magnetic field lines along the central axes of the first coil 111 and the second coil 112. Then, this high-frequency current can be supplied to an external device from the first connection terminal 51 or the second connection terminal 52.

[0067] The coil component 10 can also be used in a transformer, a DC-DC converter, an antenna, and the like. For example, when the coil component 10 functions as a primary coil of a transformer, the first connection terminal 51 and the second connection terminal 52 are connected to an AC power supply. When a high-frequency current is supplied, magnetic flux can be supplied to the iron core from the center of the first coil 111 and the second coil 112. When the coil component 10 is used in a DC-DC converter, for example, a DC power supply is connected to the first connection terminal 51, and a current can be passed from the second connection terminal 52 to the capacitor side.

[0068] As described above, the coil device 10 according to this embodiment includes the first coil 111 and the second coil 112 stacked on the first coil 111, and the specific gravity of the first coil 111 is different from the specific gravity of the second coil 112. Specifically, in this embodiment, the specific gravity of the second coil 112 is smaller than the specific gravity of the first coil 111.

[0069] In this case, for example, when comparing a single coil made of copper with the first coil 111 made of copper and the second coil 112 made of aluminum according to the present embodiment at the same volume, the present embodiment is lighter. On the other hand, although the conductivity of aluminum is lower than that of copper, it may be able to fully satisfy the required specifications. Furthermore, when comparing a single coil made of copper with the first coil 111 made of copper and the second coil 112 made of aluminum at the same weight, the total volume of the first coil 111 and the second coil 112 according to the present embodiment is larger than that of a single coil made of copper alone. In this case, the coil performance, such as the Q value, obtained by the first coil 111 and the second coil 112 may be better than that of a single coil made of copper alone. Furthermore, even if the weight of the first coil 111 and the second coil 112 is lighter than that of a single coil made of copper, the coil performance, such as the Q value, obtained by the first coil 111 and the second coil 112 may be better than that of a single coil made of copper alone. Therefore, according to the coil device 10 of this embodiment, it is possible to ensure suitable coil performance while suppressing weight or even under conditions where there are weight restrictions.

[0070] <Second embodiment> Next, a coil device 10' according to a second embodiment will be described. Fig. 5 is a cross-sectional view of the coil device 10' taken along line III-III in Fig. 2. Fig. 6 is a cross-sectional view of the coil device 10' taken along line IV-IV in Fig. 2. Components in this embodiment that are the same as those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted.

[0071] In this embodiment, the first coil 111 has a spiral shape, and the second coil 112 has a spiral shape with the same pattern as the first coil 111. The first coil 111 and the second coil 112 overlap and contact each other so that their spiral shapes match. No intermediate coating layer 131 is provided between the first coil 111 and the second coil 112.

[0072] More specifically, a bottom surface 111Ea of a first conductor 111E of the first coil 111 is in contact with a top surface 112Ed of a second conductor 112E of the second coil 112.

[0073] The coil device 10' according to the second embodiment described above also has the effect of ensuring favorable coil performance while suppressing weight or even under weight constraints, similar to the first embodiment. When the first coil 111 and the second coil 112 are in contact as in the present embodiment, a higher Q value may be obtained than when the first coil 111 and the second coil 112 are separated as in the first embodiment. Therefore, this embodiment is very useful when there is no particular problem with the first coil 111 and the second coil 112 being in contact.

[0074] <Third embodiment> Next, a coil device 10'' according to a third embodiment will be described. FIG. 7 is a cross-sectional view of the coil device 10'' taken along line III-III in FIG. 2. Components in this embodiment that are the same as those in the first and second embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0075] As shown in FIG. 7, the coil device 10'' has a configuration in which the support member 20 and the magnetic shield member 40 are removed from the first embodiment. In this case, as in the other embodiments, the effect of ensuring suitable coil performance while suppressing weight or even under conditions where there are weight restrictions can be obtained.

[0076] <Fourth embodiment> Next, a coil device 10''' according to a fourth embodiment will be described. FIG. 8 is a cross-sectional view of the coil device 10''' corresponding to line III-III in FIG. 2. Components in this embodiment that are the same as those in the first to third embodiments are given the same reference numerals, and redundant description will be omitted.

[0077] As shown in Fig. 8, the coil device 10''' has a configuration obtained by removing the support member 20 and the magnetic shield member 40 from the second embodiment. In this case, as in the other embodiments, the effect of ensuring suitable coil performance while suppressing weight or even under conditions where there are weight restrictions can be obtained.

[0078] <Evaluation by simulation> Next, we will explain the results of a simulation evaluation of the coil performance of the above embodiment. The simulation was performed by setting various conditions such as the dimensions and materials of each part of the coil component, and the frequency of the supplied high-frequency current, and then analyzing the magnetic field using the finite element method. Then, based on the simulated magnetic field, the Q value, inductance (L), impedance (Z), loss (LOSS), etc. were derived.

[0079] The simulation was performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd.

[0080] (Simulation pattern 1) First, in Simulation Pattern 1, a magnetic field simulation was performed on the coil device 10 according to the first embodiment, and the results were compared with Comparative Examples 1 to 5.

[0081] "Simulation example of embodiment" In simulation pattern 1, magnetic field simulations (simulation examples 1 to 5) were performed for coil devices 10 according to five patterns of the embodiment. As common conditions for simulation examples 1 to 5, the following were set for coil device 10 according to the embodiment. The first coil 111 and the second coil 112 have the same spiral shape. The maximum length LD of the first coil 111 and the second coil 112 in plan view is 600 mm, and the maximum length SD is 500 mm (see FIG. 2). The spiral shape is the one shown in FIG. 2, and is a shape that rotates nine times. The wire width of the first coil 111 and the wire width of the second coil 112 are 9 mm. The distance between adjacent spiral windings is 9 mm. The gap in the axial direction between the first coil 111 and the second coil 112 is 0.1 mm. The supplied high frequency current is 40 A and the frequency is 85 KHz. The material of the first coil 111 is copper, and the electrical conductivity is 6.45×10 7 [S / m]. The material of the second coil 112 is aluminum, and the electrical conductivity is 3.83×10 7 [S / m]. The magnetic shield member 40 is a ferrite plate, and the electrical conductivity is 1.67×10 -1 [S / m] and the relative permeability is 3000. The coil and air layer were divided into 300,000 to 500,000 meshes and the simulation was carried out.

[0082] In simulation examples 1 to 5, the thickness of the first copper coil 111 and the thickness of the second aluminum coil 112 were changed as follows, the weight was derived by calculation, and the Q value was derived from an analysis of the simulated magnetic field.

[0083] Simulation example 1 (SIM-1) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.2 mm. Simulation example 2 (SIM-2) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.4 mm. Simulation example 3 (SIM-3) The thickness of the first coil 111 is 0.3 mm, and the thickness of the second coil 112 is 0.3 mm. Simulation example 4 (SIM-4) The first coil 111 has a thickness of 0.4 mm, and the second coil 112 has a thickness of 0.4 mm. Simulation example 5 (SIM-5) The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm.

[0084] "Comparative Examples 1-2" In Comparative Examples 1 and 2, a magnetic field simulation was performed for an aluminum coil having the same spiral shape as the first coil 111 and the second coil 112. The dimensions of the aluminum coil in plan view are the same as those of Simulation Examples 1 to 5. The electrical conductivity of aluminum is the same as the value set in the simulation for the embodiment. The aluminum coil is placed on a magnetic shield member 40 made of a ferrite plate set in the simulation for the embodiment.

[0085] The thickness of the aluminum coil was then changed as follows, the weight was calculated, and the Q value was derived from an analysis of the simulated magnetic field.

[0086] Comparison Example 1 The thickness of the aluminum coil is 0.8 mm. Comparative Example 2 The thickness of the aluminum coil is 1.0 mm.

[0087] "Comparative Examples 3 to 8" In Comparative Examples 3 to 8, magnetic field simulations were performed for copper coils having the same spiral shape as first coil 111 and second coil 112. The dimensions of the copper coil in plan view are the same as those in Simulation Examples 1 to 5. The electrical conductivity of copper is the same as the value set in the simulation for the embodiment. The copper coil is placed on a magnetic shield member 40 made of a ferrite plate set in the simulation for the embodiment.

[0088] The thickness of the copper coil was then changed as follows, the weight was calculated, and the Q value was derived from an analysis of the simulated magnetic field.

[0089] Comparative Example 3 The thickness of the copper coil is 0.2 mm. Comparative Example 4 The thickness of the copper coil is 0.3 mm. Comparative Example 5 The thickness of the copper coil is 0.4 mm. Comparative Example 6 The thickness of the copper coil is 0.5 mm. Comparative Example 7 The thickness of the copper coil is 0.6 mm. Comparative Example 8 The thickness of the copper coil is 0.8 mm.

[0090] "Comparative Examples 9 to 12" In Comparative Examples 9 to 12, magnetic field simulations were performed for cases where copper coils having the same spiral shape as the first coil 111 and the second coil 112 were stacked in two layers. The dimensions of the copper coil in plan view are the same as those in Simulation Examples 1 to 5. The electrical conductivity of copper is the same as the value set in the simulation for the embodiment. The copper coil is placed on a magnetic shield member 40 made of a ferrite plate set in the simulation for the embodiment.

[0091] The thickness of the copper coil was then changed as follows, the weight was calculated, and the Q value was derived from an analysis of the simulated magnetic field.

[0092] Comparative Example 9 The thickness of one copper coil is 0.4 mm, and the total thickness is 0.8 mm. Comparative Example 10 The thickness of one copper coil is 0.3 mm, and the total thickness is 0.6 mm. Comparative Example 11 The thickness of one copper coil is 0.2 mm, and the total thickness is 0.4 mm. Comparative Example 12 The thickness of one copper coil is 0.14 mm, and the total thickness is 0.28 mm.

[0093] The simulation results for thickness setting, weight, and Q value for each of Simulation Examples 1 to 5 and Comparative Examples 1 to 12 are shown in Table 1 below. Also, Fig. 9 is a graph showing the simulation results for performance evaluation of Simulation Examples 1 to 5 and Comparative Examples 1 to 12. In Fig. 9, the horizontal axis represents the thickness per meter of the metal that is the material of each coil before being processed into a coil. 2 The vertical axis shows the weight (kgf) per unit mass, the vertical axis shows the Q value, and the corresponding points of the simulation results are shown and connected by a broken line. In the case of a combination of multiple metals, for example, in the case of SIM-1, copper 0.2 mm and aluminum 0.2 mm, 2 The weight of the coil is the weight of the required area and the weight of the unnecessary parts removed, so it will be much smaller than the value on the horizontal axis.

[0094] [Table 1]

[0095] For example, when transmitting power to an electric vehicle, a Q value of 150 or higher is desirable. If the weight of copper exceeds 5 kgf, the material cost increases. If the thickness is greater than 0.5 mm for a single layer, it becomes difficult to roll the raw copper foil into a roll, and when punching with a die, the life of the punching blade increases, placing a heavy burden on the manufacturing process. Considering the vehicle's installation, it is desirable to keep the weight as small as possible. Considering the impact on copper resources, it is desirable to use as little copper as possible on the ground side, as the surface area is large.

[0096] Considering the above points, Simulation Examples 2 to 5 satisfy the preferable conditions.

[0097] On the other hand, Comparative Examples 1 and 2, which are aluminum coils, are lightweight but thick and have undesirable processability. As shown in Figure 9, aluminum coils are advantageous in terms of increasing the Q value while keeping the weight low. However, their thicker thickness makes them undesirable for processability. To ensure a Q value of 150 or more, the thickness of a single layer of aluminum coil must be significantly greater than 0.5.

[0098] Comparative Examples 5 and 6, which are copper coils, satisfy the preferable conditions. However, the thickness of the copper coil is relatively large. Comparative Examples 7 and 8 are unfavorable in terms of material cost and processability.

[0099] Comparative Example 11, which is based on stacked copper coils, meets the desirable conditions, but the Q value is not sufficiently high. Comparative Examples 9 and 10 are undesirable in terms of material cost in terms of weight.

[0100] Considering the above results, Simulation Examples 2 to 5 are more rationally constructed than Comparative Examples 1 to 12 in terms of ensuring the Q value, reducing weight, processability, and reducing material costs.

[0101] Furthermore, for example, when comparing Simulation Example 3, which weighs 3.5 kgf, with Comparative Example 5, which weighs 3.6 kg, the coil component according to the present embodiment, despite being approximately the same weight, ensures a higher Q value (187 > 171). Similarly, when comparing Simulation Example 4, which weighs 4.6 kgf, with Comparative Example 6, which weighs 4.5 kg, the coil component according to the present embodiment, despite being approximately the same weight, ensures a higher Q value (202 > 189). This trend exists in the weight range of 2 kgf to 6 kgf, as shown in FIG. 9. This confirms the effect of the present disclosure, that is, that favorable coil performance can be ensured even under weight-restricted conditions.

[0102] Furthermore, for example, when comparing Simulation Example 3, which has a Q value of 187, with Comparative Example 6, which has a Q value of 189, the weight of the coil component according to this embodiment is smaller than that of Comparative Example 6 (4.5 kgf > 3.5 kgf), even though the Q values ​​are about the same. This tendency exists in the Q value range of 150 to 200, as shown in FIG. 9. This confirms the effect of the present disclosure, that is, the ability to ensure favorable coil performance while suppressing weight.

[0103] (Simulation pattern 2) In simulation pattern 2, magnetic field simulations (modification simulations 1 to 3) were performed for modifications in which the positions of the first coil 111 and the second coil 112 were interchanged in coil device 10 according to the first embodiment. These were then compared with simulation examples 1 to 5 in simulation pattern 1.

[0104] In the modified simulations 1 to 3, the thicknesses of the first copper coil 111 and the second aluminum coil 112 were changed as follows, the weights were calculated, and the Q values ​​were derived from the analysis of the simulated magnetic field. The simulation settings and conditions were the same as those for simulation pattern 1.

[0105] · Variation Simulation 1 The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. - Variation Simulation 2 The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm. - Variation Simulation 3 The thickness of the first coil 111 is 0.3 mm, and the thickness of the second coil 112 is 0.3 mm.

[0106] The simulation results for thickness setting, weight, and Q value for each of Simulation Examples 1 to 5 and Modified Simulation Examples 1 to 3 are shown in Table 2 below. Also, Fig. 10 is a graph showing the simulation results for performance evaluation of Simulation Examples 1 to 5 and Modified Simulation Examples 1 to 3. In Fig. 10, as in the above, the horizontal axis represents the thickness per meter of the metal that is the material of each coil before it is processed into a coil. 2 The vertical axis indicates the weight per unit mass (kgf), the vertical axis indicates the Q value, and the corresponding points of the simulation results are shown.

[0107] [Table 2]

[0108] In simulation pattern 2, it was confirmed that a higher Q value can be ensured when the second coil 112 with lower conductivity (higher resistance value) is arranged on the magnetic shield member 40 side than when the first coil 111 with higher conductivity (lower resistance value) is arranged on the magnetic shield member 40 side. In other words, the embodiment is more advantageous than the modified example in terms of ensuring a Q value. Therefore, it was confirmed that care should be taken with the layout when using a magnetic body such as the magnetic shield member 40 and two or more coils made of different materials at the same time.

[0109] (Simulation pattern 3) In simulation pattern 3, magnetic field simulations (Simulation Examples 6 to 15) were performed for the coil device 10'' according to the third embodiment and the coil device 10''' according to the fourth embodiment, and were compared with Comparative Examples 13 to 17.

[0110] The common conditions for simulation examples 6 to 15 are the same as simulation pattern 1, except that there is no magnetic shield member 40 and the gap between the first coil 111 and the second coil 112 is changed for each simulation example. In simulation examples 6 to 15, the thickness of the first copper coil 111 and the thickness of the second aluminum coil 112 were changed as follows, and the Q value, inductance L, impedance Z, and LOSS were derived from an analysis of the simulated magnetic field.

[0111] "Simulation example of embodiment" Simulation example 6 (SIM-6) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.5 mm. Simulation example 7 (SIM-7) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.1 mm. Simulation example 8 (SIM-8) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0 mm. Simulation example 9 (SIM-9) The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0 mm. Simulation example 10 (SIM-10) The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm. The distance between the first coil 111 and the second coil 112 in the axial direction is 0.02 mm. Simulation example 11 (SIM-11) The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.1 mm. Simulation example 12 (SIM-12) The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.2 mm. Simulation example 13 (SIM-13) The thickness of the first coil 111 is 0.5 mm, and the thickness of the second coil 112 is 0.2 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.5 mm. Simulation example 14 (SIM-14) The thickness of the first coil 111 is 0.3 mm, and the thickness of the second coil 112 is 0.3 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.2 mm. Simulation example 15 (SIM-15) The thickness of the first coil 111 is 0.3 mm, and the thickness of the second coil 112 is 0.3 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.5 mm.

[0112] "Comparative Examples 13-14" In Comparative Examples 13 and 14, a magnetic field simulation was performed for a copper coil (without ferrite) having the same spiral shape as the first coil 111 and the second coil 112. The dimensions of the copper coil in plan view are the same as those of Simulation Examples 6 to 15. The electrical conductivity of copper is the same as that set in Simulation Examples 6 to 15.

[0113] Then, the thickness of the copper coil was changed as follows, and the Q value, inductance L, impedance Z, and LOSS were derived from the analysis of the simulated magnetic field.

[0114] Comparative Example 13 The thickness of the copper coil is 0.5 mm. Comparative Example 2 The thickness of the copper coil is 0.7 mm.

[0115] "Comparative Example 15" In Comparative Example 15, a simulation was carried out of the magnetic field generated when aluminum coils having the same spiral shape as the first coil 111 and the second coil 112 were stacked in two layers. The dimensions of the aluminum coil in plan view are the same as those of Simulation Examples 6 to 15. The electrical conductivity of aluminum is the same as that set in Simulation Examples 6 to 15.

[0116] The thickness of the aluminum coil was set as follows, and the Q value, inductance L, impedance Z, and LOSS were derived from the analysis of the simulated magnetic field.

[0117] Comparative Example 15 The thickness of one of the two aluminum coils is 0.2 mm, the thickness of the other is 0.5 mm, and the axial distance between the aluminum coils is 0.5 mm.

[0118] "Comparative Example 16" In Comparative Example 16, a magnetic field simulation was performed for an aluminum coil (without ferrite) having the same spiral shape as the first coil 111 and the second coil 112. The dimensions of the aluminum coil in plan view are the same as those of Simulation Examples 6 to 15. The electrical conductivity of aluminum is the same as that set in Simulation Examples 6 to 15.

[0119] The thickness of the aluminum coil was set as follows, and the Q value, inductance L, impedance Z, and LOSS were derived from the analysis of the simulated magnetic field.

[0120] Comparative Example 16 The thickness of the aluminum coil is 0.7 mm.

[0121] "Comparative Example 17" In Comparative Example 17, a simulation was carried out of the magnetic field generated when copper coils having the same spiral shape as the first coil 111 and the second coil 112 were stacked in two layers. The dimensions of the copper coil in plan view are the same as those of Simulation Examples 6 to 15. The electrical conductivity of copper is the same as that set in Simulation Examples 6 to 15.

[0122] The thickness of the copper coil was set as follows, and the Q value, inductance L, impedance Z, and LOSS were derived from the analysis of the simulated magnetic field.

[0123] Comparative Example 17 One of the two copper coils has a thickness of 0.5 mm, the other has a thickness of 0.2 mm, and the axial distance between the copper coils is 0.5 mm.

[0124] The simulation results of thickness settings, gap distances, Q values, inductances, impedances, and losses for Simulation Examples 6 to 15 and Comparative Examples 13 to 17 are shown in Table 3 below.

[0125] [Table 3]

[0126] In Simulation Examples 6 to 15, the thickness of the entire coil is 0.6 mm or 0.7 mm, which is relatively thick, ensuring a suitable Q value for in-vehicle applications.

[0127] Comparing Simulation Example 8 and Comparative Example 13, the Q values ​​are the same. On the other hand, Simulation Example 8 uses a copper first coil 111 having a thickness of 0.2 mm, whereas Comparative Example 13 uses a copper coil having a thickness of 0.5 mm. In this case, although the Q values ​​are the same, the effects of weight reduction and material cost reduction achieved by the coil component according to the present disclosure are beneficial.

[0128] Furthermore, considering Simulation Examples 6 to 8 and Simulation Examples 9 to 13, it can be seen that the narrower the gap between the coils, the higher the Q value. In particular, the Q value of Simulation Example 9 is 230, which is extremely high. Although the Q value of Simulation Example 9 is smaller than the Q value of the 0.7 mm copper coil of Comparative Example 14, which is 245, it can be said to be extremely beneficial in terms of reducing weight and material costs.

[0129] (Simulation pattern 4) In simulation pattern 4, magnetic field simulations (simulation examples 16 to 19) were performed on the coil device 10 according to the first embodiment to verify the performance improvement achieved by the magnetic shield member 40. The results were compared with several examples of simulation pattern 3.

[0130] The common conditions for Simulation Examples 16 to 19 are the same as those for Simulation Pattern 1. In Simulation Examples 16 to 19, the thickness of the first copper coil 111 and the thickness of the second aluminum coil 112 were changed as follows, and the Q value, inductance L, impedance Z, and LOSS were derived from an analysis of the simulated magnetic field.

[0131] "Simulation example of embodiment" Simulation example 16 (SIM-16) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0 mm. Simulation example 17 (SIM-17) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance between the first coil 111 and the second coil 112 in the axial direction is 0.02 mm. Simulation example 18 (SIM-18) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.1 mm. Simulation Example 19 (SIM-19) The thickness of the first coil 111 is 0.2 mm, and the thickness of the second coil 112 is 0.5 mm. The distance in the axial direction between the first coil 111 and the second coil 112 is 0.5 mm.

[0132] The simulation results for thickness setting, gap distance, Q value, inductance (L), impedance (Z), and loss (LOSS) for each of Simulation Examples 16 to 19 are shown in Table 4 below. Fig. 11 is a graph showing the simulation results for performance evaluation of Simulation Examples 16 to 19 and the aforementioned Simulation Examples 9 to 13. In Fig. 11, the horizontal axis represents the axial distance (mm) between first coil 111 and second coil 112, the vertical axis represents the Q value, and corresponding points in the simulation results are shown.

[0133] [Table 4]

[0134] Comparing Simulation Example 16 with Simulation Example 9, the thickness of the copper first coil 111 in Simulation Example 16 is smaller than the thickness of the copper first coil 111 in Simulation Example 9. On the other hand, the Q value of Simulation Example 16 is 234 and the Q value of Simulation Example 9 is 230, so the two are roughly the same. Therefore, the effect of improving the Q value by providing the magnetic shield member 40 can be confirmed.

[0135] Comparing Simulation Example 17 with Simulation Example 10, the thickness of the copper first coil 111 in Simulation Example 17 is smaller than the thickness of the copper first coil 111 in Simulation Example 10. On the other hand, the Q value of Simulation Example 17 is 197, and the Q value of Simulation Example 10 is 202, so they are roughly the same. Therefore, the effect of improving the Q value by providing the magnetic shield member 40 can be confirmed. The effect of improving the Q value by providing the magnetic shield member 40 can also be confirmed by comparing Simulation Example 18 with Simulation Example 11, and comparing Simulation Example 19 with Simulation Example 11.

[0136] In simulation pattern 4, the effect of improving coil performance due to the magnetic shield member 40 (ferrite) was confirmed.

[0137] Although the embodiments of the present disclosure have been described above, various modifications may be made to the above-described embodiments, and such modifications are also within the technical scope of the present disclosure. [Explanation of symbols]

[0138] S...Power transmission system 1...Power transmission device 1A...High frequency current supply unit 2...Power receiving device 2A...Conversion unit 10, 10', 10'', 10''... Coil parts 111...First coil 111E…first conductor 111A...Inner circumference end 111B...Outer edge 111Ea...bottom 111Eb…1st side 111Ec…Second side 111Ed…Top surface 112...Second coil 112E…Second conductor 112A...Inner circumference end 112B…Outer edge 112C...crosspiece 112Ea…Bottom surface 112Eb…1st side 112Ec…Second side 112Ed…Top surface 121...Base material layer 131...Intermediate coating layer 131A...First through hole 131B...Second through hole 141…Surface coating layer 141A...First through hole 141B...Second through hole 20...Support member 22...Bottom plate part 23...Side plate part 40...Magnetic shielding member 51...First connection terminal 52...Second connection terminal

Claims

1. a first coil; a second coil overlapped with the first coil; a magnetic member including a magnetic substance, the specific gravity of the first coil is different from the specific gravity of the second coil; the second coil has a lower conductivity than the first coil; the first coil is formed of copper or a copper alloy; the second coil is made of aluminum or an aluminum alloy; A coil component in which the magnetic member, the second coil, and the first coil are arranged in this order.

2. The coil component according to claim 1 , wherein the specific gravity of the second coil is smaller than the specific gravity of the first coil.

3. The coil component according to claim 1 , wherein the magnetic material is ferrite.

4. the first coil overlaps the second coil with a gap therebetween, the first coil has a first end and a second end, and the second coil has a first end and a second end; 4. The coil component according to claim 1, wherein one of the first end and the second end of the first coil is electrically connected to one of the first end and the second end of the second coil, and the other of the first end and the second end of the first coil is electrically connected to the other of the first end and the second end of the second coil.

5. The coil component according to claim 4 , wherein the first coil overlaps the second coil via an insulating layer disposed in the gap.

6. the first coil has a spiral shape; the second coil has a spiral shape; the first end portion as an inner peripheral end portion of the first coil is electrically connected to the first end portion as an inner peripheral end portion of the second coil, and the second end portion as an outer peripheral end portion of the first coil is electrically connected to the second end portion as an outer peripheral end portion of the second coil, The coil component according to claim 5 , wherein the first end of the first coil is connected to the first end of the second coil through a hole provided in the insulating layer.

7. the first coil has a spiral shape; the second coil has a spiral shape; The coil component according to claim 1 , wherein the first coil and the second coil overlap and contact each other so that their spiral shapes match each other.

8. the first coil is plate-shaped; The coil component according to claim 1 , wherein the second coil is plate-shaped.

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

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

11. The power transmission device includes a power receiving device. A power transfer system, wherein at least one of the power transmitting device and the power receiving device comprises the coil component according to claim 1 .

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