JP2024097207A - Coil component, power transmitter, power receiver, and power transmission system - Google Patents

Abstract

To provide a coil component whose performance can be effectively improved by a magnetic material.SOLUTION: A coil component 10 includes: a magnetic shield member 20 having magnetism; a first planar coil 11 which is laminated above the magnetic shield member 20 with a gap provided therebetween; a second planar coil 12 which is disposed between the magnetic shield member 20 and the first planar coil 11; and magnetic material wall parts 40. The magnetic material wall parts 40 are inserted through a radial gap of the first planar coil 11 and through a radial gap of the second planar coil 12 in a lamination direction of the first planar coil 11 and the second planar coil 12. An upper end part 41, which is one end in the lamination direction of the magnetic material wall part 40, extends over a surface opposite to a surface, of the first planar coil 11, facing the second planar coil 12. A lower end part 42 is flush with or extends over a surface, of the second planar coil 12, facing the magnetic shield member 20.SELECTED DRAWING: Figure 5

Description

This disclosure relates to coil components, power transmission devices, power receiving devices, and power transmission systems.

Wireless power transmission systems that transmit power contactlessly are becoming more common.

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

When a high-frequency current is passed through a coil, a skin effect can occur. The skin effect increases AC resistance, which reduces the transmission efficiency during power transmission. If the coil is made of Litz wire, taking this into consideration, the skin effect can be suppressed, and therefore the reduction in transmission efficiency can be suppressed. However, Litz wire is made by twisting together many enameled wires, so it is expensive to manufacture and requires a lot of work, and the larger the coil, the more work it takes to manufacture.

On the other hand, there is also known a technology that employs a planar coil that is spirally shaped and plate-like, with a rectangular cross section of the conductor wire (see Patent Document 1). Such a planar coil can be formed, for example, by punching it out from a sheet material. Therefore, such a planar coil can improve manufacturing efficiency regardless of the size of the coil. It is also advantageous in terms of making the device into which the coil is incorporated thinner and lighter.

Patent document 1 also discloses a structure in which a magnetic body is provided so as to overlap the coil, and the magnetic body is provided between adjacent turns of the coil. This structure makes it possible to suppress the increase in loss due to the proximity effect between the turns.

JP 2020-47614 A

As described above, when a magnetic material is provided around the coil, the coil performance, such as the Q value, can be improved. However, magnetic materials are expensive and relatively heavy. Therefore, when a large amount of magnetic material is used, although the coil performance is improved, it may not be possible to meet the desired specifications in terms of cost and weight.

The objective of the present disclosure is to provide a coil component, a power transmission device, a power receiving device, and a power transmission system that can effectively improve performance by using magnetic materials.

Embodiments of the present disclosure relate to the following [1] to [23].

[1] A magnetic shield member having magnetism;
a first planar coil overlapping the magnetic shield member with a gap therebetween;
a second planar coil disposed between the magnetic shield member and the first planar coil;
a magnetic wall portion having magnetism, the first planar coil and the second planar coil being passed through radial gaps in the first planar coil and radial gaps in the second planar coil in a direction in which the first planar coil and the second planar coil overlap, one end of the first planar coil in the overlapping direction extending beyond a surface of the first planar coil opposite a surface that faces the second planar coil, and the other end of the second planar coil in the overlapping direction being flush with a surface of the second planar coil that faces the magnetic shield member or extending beyond the facing surface.

[2] The coil component described in [1], further comprising a holder including a first interlayer portion disposed between the first planar coil and the second planar coil, and a second interlayer portion disposed between the second planar coil and the magnetic shielding member.

[3] The holder has a slit penetrating or recessed in a direction from the first planar coil toward the magnetic shield member,
The coil component according to [2], wherein the magnetic wall portion passes through a radial gap of the first planar coil, a radial gap of the second planar coil, and the slit.

[4] The coil component described in [1], in which an air layer is formed at least either between the magnetic shield member and the second planar coil or between the second planar coil and the first planar coil.

[5] A coil component according to any one of [1] to [4], in which the other end of the magnetic wall portion is in contact with the magnetic shield member.

[6] The magnetic wall portion has a spiral shape,
The coil component according to any one of claims 1 to 5, wherein the magnetic wall portion passes through a radial gap that forms a spiral shape of the first planar coil and a radial gap that forms a spiral shape of the second planar coil.

[7] The first planar coil and the second planar coil are connected in series,
the second planar coil comprises aluminum;
The coil component according to any one of [1] to [6], wherein a thickness of the first planar coil is not less than 0.15 mm and not more than 0.35 mm.

[8] A coil component according to any one of [1] to [7], in which the thickness of the second planar coil is greater than the thickness of the first planar coil.

[9] The coil component according to any one of [1] to [8], wherein a specific gravity of the first planar coil is greater than a specific gravity of the second planar coil, and a conductivity of the first planar coil is greater than a conductivity of the second planar coil.
［

[10] The coil component according to any one of [1] to [9], wherein the first planar coil contains copper.

[11] The coil component according to any one of [1] to [10], wherein the first planar coil and the second planar coil are supplied with an AC current of 79 KHz or more and 90 KHz or less, or are supplied with an AC magnetic field of 79 KHz or more and 90 KHz or less.

[12] The coil component according to any one of [1] to [11], wherein the thickness of the second planar coil is 0.5 mm or more and 1.0 mm or less.

[13] The coil component according to any one of [1] to [12], wherein the magnetic wall portion includes a resin and magnetic particles held in the resin.

[14] A coil component according to any one of [1] to [13], in which the relative permeability of the magnetic wall portion is 5.0 or more.

[15] The coil component according to any one of [1] to [14], wherein the magnetic shielding member includes plate-shaped ferrite.

[16] A coil component according to any one of [1] to [15], in which the relative permeability of the magnetic shielding member is 500 or more.

[17] Further comprising an even number of other planar coils disposed between the first planar coil and the second planar coil,
the first planar coil, the other planar coil, and the second planar coil are connected in series;
The coil component according to any one of [1] to [16], wherein a thickness of at least the different planar coil among the planar coil connected to the second planar coil in the other planar coil and the planar coil different from the planar coil is 0.15 mm or more and 0.35 mm or less.

[18] A power transmission device comprising a coil component according to any one of [1] to [17].

[19] The power transmission device described in [18] further includes a high-frequency current supply unit that supplies an alternating current of 79 KHz or more and 90 KHz or less to the coil component.

[20] A power receiving device comprising a coil component according to any one of [1] to [17].

[21] The power receiving device according to [20], further comprising a conversion unit that converts an AC current of 79 KHz or more and 90 KHz or less generated by electromagnetic induction in the coil component into a DC current.

[22] A power transmission device and a power receiving device,
A power transfer system, wherein at least one of the power transmitting device and the power receiving device is provided with the coil component according to any one of [1] to [17].

[23] A step of supplying an AC current of 79 KHz or more and 90 KHz or less to the coil component in a power transmission device including the coil component according to any one of [1] to [17];
and receiving the magnetic field generated by the power transmitting device with a power receiving device.

According to the present disclosure, magnetic materials can effectively improve performance.

1 is a diagram illustrating a schematic diagram of a wireless power transmission system to which a coil component according to a first embodiment is applied. FIG. 1 is a perspective view of a coil component according to a first embodiment. FIG. 3 is an exploded perspective view of the coil component shown in FIG. 2 . 4 is a perspective view showing a cross section of the coil component taken along line IV-IV in FIG. 2 . 4 is a cross-sectional view of the coil component taken along line IV-IV in FIG. 2. 3 is a graph showing the relationship between the thickness and performance (Q value) of the first planar coil and the second planar coil constituting the coil component shown in FIG. 2 . FIG. 11 is a cross-sectional view of a coil component according to a second embodiment. FIG. 11 is a cross-sectional view of a coil component according to a third embodiment. FIG. 13 is a cross-sectional view of a coil component according to a fourth embodiment. FIG. 13 is a cross-sectional view of a coil component according to a fifth embodiment.

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

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

<<First embodiment>>
Fig. 1 is a schematic diagram of a wireless power transmission system S to which a coil component 10 according to a first embodiment is applied. First, the wireless power transmission system S (hereinafter, abbreviated as power transmission system S) will be described with reference to Fig. 1. It goes without saying that a coil component according to an embodiment different from the first embodiment can be applied to the power transmission system S.

<Wireless power transmission system>
The power transfer 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 supplying unit 1A. The coil component 10 in the power transmitting device 1 functions as a power transmitting coil. The high-frequency current supplying unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil.

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 has a rectifier circuit that converts the high-frequency current into a direct current. The conversion unit 2A may be configured to include, for example, a full-wave rectifier circuit including multiple diodes and a smoothing capacitor.

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.

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 by 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. That is, the power receiving device 2 receives a magnetic field from the power transmitting device 1 or is influenced by the magnetic field in the power transmitting device 1, and causes a high-frequency current to flow by electromagnetic induction. The conversion unit 2A converts this high-frequency current into a direct current, and supplies the converted direct current to, for example, a battery (not shown).

As an example, the coil component 10 according to the embodiment described below is manufactured so that its performance is improved when it is supplied with an AC current of 75 KHz to 100 KHz or an AC magnetic field of 75 KHz to 100 KHz. In detail, the coil component 10 is manufactured so that its performance is particularly improved when it is supplied with an AC current of 79 KHz to 90 KHz, particularly an AC current of 85 KHz, or an AC magnetic field of 79 KHz to 90 KHz, particularly an AC magnetic field of 85 KHz. Therefore, the high-frequency current supply unit 1A may supply, for example, an AC current of 75 KHz to 100 KHz, an AC current of 79 KHz to 90 KHz, or an AC current of 85 KHz, so as to correspond to the AC current desired for the coil component 10. The conversion unit 2A may also be configured to convert an AC current of 75 KHz to 100 KHz, an AC current of 79 KHz to 90 KHz, or an AC current of 85 KHz, generated by electromagnetic induction when an AC magnetic field is supplied, into a DC current.

The power transmission system S shown in FIG. 1 employs a magnetic resonance method as the power transmission method. However, the coil component 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 transmission device 1 is installed on a road, a parking lot, or the like. The power receiving device 2 is installed in the electric vehicle.

However, the use of the power transmission system S is not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to flying objects such as drones and robots. The power transmission system S may also be used to transmit power to submarines and exploration robots 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 transformers, DC-DC converters, antennas, etc.

<Coil parts>
The coil component 10 will be described below. Fig. 2 is a perspective view of the coil component 10. Fig. 3 is an exploded perspective view of the coil component 10. Fig. 4 is a perspective view of a cross section of the coil component 10 taken along line IV-IV in Fig. 2. Fig. 5 is a cross section of the coil component 10 taken along line IV-IV in Fig. 2.

As shown in Figures 2 to 5, the coil component 10 includes a first planar coil 11, a second planar coil 12, a magnetic shield member 20, a holder 30, a magnetic wall portion 40, a first connection terminal 51, and a second connection terminal 52.

As shown in Figures 4 and 5, in coil component 10, second planar coil 12 and first planar coil 11 are arranged on magnetic shield member 20 so as to overlap in this order. First planar coil 11 and second planar coil 12 are connected in series and overlap with a gap. Second planar coil 12 and magnetic shield member 20 also overlap with a gap. Note that in Figure 2, for ease of explanation, second planar coil 12 arranged between first planar coil 11 and magnetic shield member 20 is shown in parentheses.

The holder 30 functions to maintain the gap between the first planar coil 11 and the second planar coil 12, and to maintain the gap between the second planar coil 12 and the magnetic shield member 20. The holder 30 also functions to integrate the first planar coil 11 and the second planar coil 12.

Figure 3 shows the magnetic wall portion 40 separated from the other portions (11, 12, 30, 51, 52). As will be described in detail later, the holder 30 has a slit 36 that penetrates or recesses in a direction from the first planar coil 11 toward the magnetic shield member 20. In this embodiment, the magnetic wall portion 40 is inserted into the slit 36, thereby being integrated with the holder 30. Each portion of the coil component 10 will be described in detail below.

(First Planar Coil and Second Planar Coil)
First planar coil 11 has a spiral shape and is made of a conductive material. In the present embodiment, first planar coil 11 includes copper. More specifically, first planar coil 11 is made of copper.

The first planar coil 11 is plate-shaped, and as shown in Figures 4 and 5, the cross-sectional shape of the first planar coil 11 in a direction perpendicular to the direction in which the first planar coil 11 winds in a spiral shape is rectangular.

The symbol C1 in Figures 2 and 3 indicates the first central axis of the first planar coil 11, which passes through the center of the spiral shape of the first planar coil 11. Hereinafter, when the axial direction of the first planar coil 11 is mentioned, this direction means a direction extending on the first central axis C1 or a direction parallel to the first central axis C1. In addition, the direction perpendicular to the first central axis C1 is referred to as the radial direction of the first planar coil 11.

The first planar coil 11 has a conductor 11E having a spiral shape formed by a plurality of turn portions 11n. The plurality of turn portions 11n of the first planar coil 11 are arranged in a direction perpendicular to the first central axis C1 of the spiral shape. More specifically, the plurality of turn portions 11n are connected so as to gradually move away from the first central axis C1 of the spiral shape in a radially outward direction. This forms the spiral shape.

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

In the following, the turn portion 11n that is closest to the first central axis C1 may be referred to as the turn portion 111. Also, the turn portion connected to the turn portion 111 may be referred to as the turn portion 112. In this embodiment, the turn portions 11n are made up of seven turn portions 111 to 117. In the following, when describing matters common to each of the turn portions 11n, they will basically be referred to as the turn portion 11n.

In this embodiment, the turn portion 11n winds around to form a rectangle. However, the turn portion 11n may also have a shape that winds around to form a circle. Note that the spiral shape referred to in this specification and disclosure means a planar curved shape wound in a spiral shape. The planar curved shape referred to here also includes a planar pattern that winds around repeatedly while bending in a broken line shape as shown in the figure. In other words, the spiral shape is a shape that winds around the first central axis C1 of the first planar coil 11 so as to be gradually positioned outward.

The radially inner end (the end close to the first central axis C1) of the turn portion 111 closest to the first central axis C1 is electrically connected to the second planar coil 12. The connection wiring portion 14 shown in FIG. 2 and FIG. 3 is a conductor and electrically connects the turn portion 111 and the second planar coil 12 in series. The connection wiring portion 14 shown in the figure is formed integrally with the first planar coil 11 as an example. The connection wiring portion 14 may be connected to the second planar coil 12 by ultrasonic connection or the like. On the other hand, the radially outer end (the end away from the first central axis C1) of the turn portion 117 that is the furthest from the first central axis C1 among the multiple turn portions 11n is connected to the first connection terminal 51.

Here, the radial inward direction of the first planar coil 11 (turn portion 11n) means a direction approaching the first central axis C1 in the radial direction. The radial outward direction of the first planar coil 11 (turn portion 11n) means a direction moving away from the first central axis C1 in the radial direction. In the present embodiment, the first central axis C1 is determined as follows. First, linear virtual turn portions having a shape similar to that of the innermost turn portion 111 are drawn inward in the radial direction in sequence from the radially inner end of the innermost turn portion 111 to form a spiral shape. Then, drawing is continued until a virtual turn portion that fits within a diameter of 1 cm can be drawn. Then, a line that passes through the radially inner region of the virtual turn portion that fits within a diameter of 1 cm in a direction perpendicular to the circumferential and radial directions of the spiral shape is determined as the first central axis C1.

In the present embodiment, the first planar coil 11 is formed by punching a copper plate into a spiral shape, as an example. However, the first planar coil 11 can also be formed by etching a copper foil into a spiral shape.

In the present embodiment, the thickness of first planar coil 11 (thickness of conductor 11E) is smaller than the thickness of second planar coil 12. In other words, the thickness of second planar coil 12 (thickness of conductor 12E) is larger than the thickness of first planar coil 11. Specifically, the thickness of first planar coil 11 is 0.15 mm or more and 0.35 mm or less.

The present inventors have found that when the first planar coil 11 and the second planar coil 12 are stacked on the magnetic shield member 20, the performance of the coil component 10 when used in a predetermined frequency band is significantly improved by setting the thickness of the first planar coil 11, which is the coil farthest from the magnetic shield member 20, to 0.15 mm or more and 0.35 mm or less. Therefore, the thickness of the first planar coil 11 is set to 0.15 mm or more and 0.35 mm or less. The above-mentioned predetermined frequency band is the frequency band of the AC current to be passed, specifically, 75 KHz or more and 100 KHz or less, and the performance of the coil component 10 is significantly improved when the frequency is 79 KHz or more and 90 KHz or less. Note that the preferred thickness of the first planar coil 11 changes when used in a frequency band other than 75 KHz or more and 100 KHz or less. However, the thickness of the first planar coil 11 is not particularly limited and may be in a range different from 0.15 mm to 0.35 mm, for example, within the range of 0.1 mm to 1.0 mm.

The radius of first planar coil 11 (the distance from first central axis C1 to the farthest point in the radial direction) may be 80 mm or more, or may be 80 mm or more and 450 mm or less. The aspect ratio of first planar coil 11 (conductor 11E) having a rectangular cross-sectional shape is determined by dividing the radial width (width in the radial direction) of first planar coil 11 (conductor 11E) by the thickness of first planar coil 11 (conductor 11E). The aspect ratio of first planar coil 11 (conductor 11E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

When transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit power of 1 Kw or more, preferably 5 Kw or more, in a high-frequency current frequency band of 10 KHz to 200 KHz, particularly 75 KHz to 100 KHz, and further 79 KHz to 90 KHz. In this case, the thickness of the first planar coil 11 made of aluminum is preferably 0.2 mm or more. From this perspective, the lower limit of the thickness of the first planar coil 11 may be set to 0.2 mm. Furthermore, when transmitting power to an electric vehicle, it is not desirable for the size to be excessively large, and the size may be limited. From this perspective, it is preferable that the first planar coil 11 and the second planar coil 12 described below, specifically the conductor 11E of the first planar coil 11 and the conductor 12E of the second planar coil 12, are formed to a size that fits within a square with one side of 800 mm.

The line width of the first planar coil 11 (line width of the conductor 11E), i.e., the radial width of each turn portion 11n (width in the radial direction), is not particularly limited. However, considering that it is possible to transmit power of 1 Kw or more, preferably 5 Kw or more, in a high-frequency current frequency band of, for example, 79 KHz to 90 KHz, the radial width of the turn portion 11n may be 2 mm or more and 20 mm or less, 2 mm or more and 16 mm or less, 2 mm or more and 12 mm or less, or 2 mm or more and 8 mm or less. The number of turns of the first planar coil 11 may be 4 to 12, but is not particularly limited.

Next, the second planar coil 12 is also spiral-shaped, and in this embodiment, the second planar coil 12 contains aluminum. More specifically, the second planar coil 12 is made of aluminum. The material of the second planar coil 12 is not particularly limited, but may be a material having a specific gravity smaller than that of the first planar coil 11, for example, an aluminum alloy. In other words, in this embodiment, the specific gravity of the first planar coil 11 is larger than that of the second planar coil 12, and the conductivity of the first planar coil 11 is larger than that of the second planar coil 12. The material of the second planar coil 12 may be copper or a copper alloy. The second planar coil 12 is also plate-shaped, and as shown in FIG. 4 and FIG. 5, the cross-sectional shape of the second planar coil 12 in a direction perpendicular to the direction in which the second planar coil 12 winds around in a spiral shape is rectangular.

The symbol C2 in Figures 2 and 3 indicates the second central axis of the second planar coil 12 that passes through the center of the spiral shape of the second planar coil 12. Hereinafter, when the axial direction of the second planar coil 12 is mentioned, this direction means a direction extending on the second central axis C2 or a direction parallel to the second central axis C2. In addition, the direction perpendicular to the second central axis C2 is referred to as the radial direction of the second planar coil 12.

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

The second planar coil 12 also has a conductor 12E having a spiral shape with multiple turn portions 12n. The multiple turn portions 12n of the second planar coil 12 are arranged in a direction perpendicular to the second central axis C2 of the spiral shape.

The connection manner of the multiple turn portions 12n and the names according to their positions (such as turn portion 121) are the same as those of turn portion 11n of first planar coil 11. In this embodiment, the number of turns of first planar coil 11 and the number of turns of second planar coil 12 are the same, and multiple turn portions 12n are composed of seven turn portions 121 to 127. Also, turn portion 12n winds around to form a rectangular shape like turn portion 11n. Note that turn portion 12n may also have a shape that winds around to form a circle. Also, the number of turns of first planar coil 11 and the number of turns of second planar coil 12 may differ. Also, for example, turn portion 11n may be rectangular and turn portion 12n may be circular.

4, in this embodiment, any one of the multiple turn portions 11n of first planar coil 11 and any one of the multiple turn portions 12n of second planar coil 12 partially overlap in the axial direction of first planar coil 11. The part of turn portion 11n of first planar coil 11 and the part of turn portion 12n of second planar coil 12 that overlap in the axial direction of first planar coil 11 extend parallel to each other with their respective winding directions aligned. The state where the winding directions are aligned means that the winding direction of first planar coil 11 and the winding direction of second planar coil 12 do not intersect at a point but overlap a certain distance on the same line.

As described above, the length of a portion of turn portion 11n of first planar coil 11 and the length of a portion of turn portion 12n of second planar coil 12, which overlap and extend parallel to each other, may be 1/2 or more, or 3/4 or more, of their respective total lengths. The inventors have found that the greater the proportion of overlap between first planar coil 11 and second planar coil 12 that extend parallel to each other, the more eddy current loss can be suppressed.

As described above, the radially inner end of the turn portion 111 closest to the first central axis C1 is electrically connected to the second planar coil 12. More specifically, the radially inner end of the turn portion 111 is connected to the inner end of the turn portion 121 in the second planar coil 12 via the connection wiring portion 14. Here, when the first planar coil 11 and the second planar coil 12 are connected, the direction in which the first planar coil 11 winds from the end not connected to the second planar coil 12 (the radially outer end of the turn portion 117) to the end connected to the second planar coil 12 is the same as the direction in which the second planar coil 12 winds from the end connected to the first planar coil 11 to the end not connected to the first planar coil 11 (the radially outer end of the turn portion 127).

The radially outer end of the turn portion 127, which is the furthest from the second central axis C2 among the multiple turn portions 12n, is connected to the second connection terminal 52. The radially inner and outer directions of the second planar coil 12 (turn portion 12n) are defined in the same manner as the radially inner and outer directions of the first planar coil 11 described above. The position of the second central axis C2 is also determined in the same manner as the first central axis C1. The second planar coil 12 in this embodiment is also formed by punching out an aluminum plate into a spiral shape, as an example. However, the second planar coil 12 can also be formed by etching an aluminum foil into a spiral shape.

The thickness of the second planar coil 12 (the thickness of the conductor 12E) may be, for example, 0.1 mm or more and 1.0 mm or less. The coil component 10 provides or receives a magnetic field from the side that is not covered by the magnetic shield member 20. According to the inventor's knowledge, good coil performance is obtained when the thickness of the coil closest to the magnetic shield member 20 is relatively large. From this perspective, the thickness of the second planar coil 12 may be 0.5 mm or more and 1.0 mm or less. It is preferable that the thickness of the second planar coil 12 be 1.0 mm or less from the viewpoint of reducing weight and preventing the product from becoming too large.

The radius of the second planar coil 12 (the distance from the second central axis C2 to the part farthest from the center in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less, as in the case of the first planar coil 11. The aspect ratio of the second planar coil 12 (conductor 12E) having a rectangular cross-sectional shape may be 2 to 12 or less, or 3 to 10 or less, as in the case of the first planar coil 11. The line width of the second planar coil 12 (line width of the conductor 12E), i.e., the radial width (diameter width) of each turn portion 12n, may be 2 mm or more and 20 mm or less, 2 mm or more and 16 mm or less, 2 mm or more and 12 mm or less, or 2 mm or more and 8 mm or less. The number of turns of the second planar coil 12 may be 4 to 12 or less, but is not particularly limited.

Furthermore, first planar coil 11 and second planar coil 12 overlap with a gap therebetween. This gap may be 0.5 mm or more and 1.5 mm or less. The size of the gap is not particularly limited, but if the gap is too large, it will hinder the thinning of coil component 10.

As described above, in this embodiment, the thickness of the first planar coil 11, which is the one of the first planar coil 11 and the second planar coil 12 that is farther from the magnetic shield member 20, is 0.15 mm or more and 0.35 mm or less. The inventors of the present invention have confirmed through experiments and simulations that the phenomenon in which the performance of the coil component 10 is significantly improved when used in a predetermined frequency band occurs under conditions that assume at least the radial width (2 mm to 20 mm) of the turn portions 11n and 12n and the number of turns (4 to 12) of the first planar coil 11 and the second planar coil 12 exemplified above. However, the present disclosure is not limited to the conditions exemplified in the embodiment. In other words, for example, the phenomenon in which the performance of the coil component 10 is significantly improved when used in a predetermined frequency band by setting the thickness of the first planar coil 11 to 0.15 mm or more and 0.35 mm or less can occur regardless of the dimensions, number of turns, etc.

(Magnetic shielding material)
The magnetic shield member 20 is provided to suppress magnetic transmission and/or leakage magnetic field. The magnetic shield member 20 is a sheet-like member separate from the first planar coil 11, the second planar coil 12, and the holding body 30. The magnetic shield member 20 being separate from the first planar coil 11, the second planar coil 12, and the holding body 30 means that the magnetic shield member 20 is not integrated with the first planar coil 11, the second planar coil 12, and the holding body 30. However, the magnetic shield member 20 and the holding body 30 may be joined via an adhesive layer or the like. The magnetic shield member 20 is formed to a size that includes the first planar coil 11 and the second planar coil 12 in a planar view. The magnetic shield member 20 overlaps the first planar coil 11, the second planar coil 12, and the holding body 30, and is in direct contact with a part of the holding body 30 (a second interlayer portion 32 described later).

The magnetic shield member 20 in this embodiment is magnetic and includes or is made of a magnetic material. In the coil component 10, a magnetic field is generated when a current is supplied to the first planar coil 11 and the second planar coil 12. The magnetic field generated in the coil component 10 spreads in all directions relative to the central axes C1 and C2 of the first planar coil 11 and the second planar coil 12. At this time, the magnetic shield member 20 has magnetism, so that the spreading magnetic flux lines can be oriented toward the central axes C1 and C2. In addition, the coil component 10 can be installed in a vehicle, and in this case, if the magnetic field generated by the coil component 10 flows toward other vehicle components, it may have an adverse effect on the vehicle components. In such a case, the magnetic shield member 20 can suppress the leakage magnetic field that does not contribute to the generation of current.

The magnetic shield member 20 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the magnetic shield member 20 includes ferrite, preferably soft ferrite. In this embodiment, the magnetic shield member 20 includes plate-shaped ferrite. More specifically, the magnetic shield member 20 is configured by arranging multiple plate-shaped ferrites in a sheet shape.

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. Note that the relative permeability in this specification is a value measured at a frequency of 85 KHz and an environmental temperature of 23 degrees.

(Holding body)
As described above, holding body 30 functions to maintain the gap between first planar coil 11 and second planar coil 12, and to maintain the gap between second planar coil 12 and magnetic shield member 20. In the present embodiment, holding body 30 also has the function of integrating first planar coil 11 and second planar coil 12. In detail, as shown in Figs. 4 and 5, holding body 30 includes a first interlayer portion 31 disposed between first planar coil 11 and second planar coil 12, and a second interlayer portion 32 disposed between second planar coil 12 and magnetic shield member 20.

In this embodiment, the first interlayer portion 31 is joined to the first planar coil 11 and the second planar coil 12, and the second interlayer portion 32 is joined to the second planar coil 12. This integrates the first planar coil 11, the second planar coil 12, and the holder 30. In detail, the first interlayer portion 31 fills the gaps between the turn portions 11n and 12n that face each other, from the innermost turn portions 111 and 121 to the outermost turn portions 117 and 127 in the first planar coil 11 and the second planar coil 12. The second interlayer portion 32 fills the gaps between all the turn portions 12n and the portions of the magnetic shield member 20 that face them, from the innermost turn portion 121 to the outermost turn portion 127 in the second planar coil 12.

The retainer 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 are also connected 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 unit.

Note that the holding body 30 may have the first interlayer portion 31 function only to maintain the gap between the first planar coil 11 and the second planar coil 12, and the second interlayer portion 32 function only to maintain the gap between the second planar coil 12 and the magnetic shield member 20. In this case, it goes without saying that the first interlayer portion 31 does not have to be joined to the first planar coil 11 and the second planar coil 12, and the second interlayer portion 32 does not have to be joined to the second planar coil 12. Furthermore, the holding body 30 may not include the outer peripheral frame portion 33 and the inner peripheral core portion 34.

The holder 30 is insulating and contains a resin. The holder 30 may be formed of, for example, an insulating resin. The resin contained in the holder 30 is not particularly limited as long as it is non-magnetic and insulating. The holder 30 may contain, for example, polyethylene or polypropylene, or may be formed of, polyethylene or polypropylene. The holder 30 may also contain, for example, fiber-reinforced plastic, or may be formed of fiber-reinforced plastic. More specifically, the holder 30 may contain, or be formed of, glass fiber-reinforced polyamide. Note that insulating means that the volume resistivity is 10 ¹⁰ Ω·m or more.

As described above, the holder 30 has a slit 36 formed therein, and the slit 36 is formed to receive the magnetic wall portion 40. In this embodiment, as shown in Figs. 4 and 5, the slit 36 penetrates the holder 30 in a direction from the first planar coil 11 toward the magnetic shield member 20. As a result, the magnetic wall portion 40 inserted into the slit 36 comes into contact with the magnetic shield member 20.

As shown in FIG. 3, the slit 36 is formed in a spiral shape. The slit 36 overlaps with the radial gap of the spiral shape of the first planar coil 11 and the radial gap of the spiral shape of the second planar coil 12. In detail, the slit 36 extends in a spiral shape from a position between the radially inner ends of the innermost turn parts 111 and 121 of the first planar coil 11 and the turn parts 112 and 122 located radially outward, passing between the radially adjacent turn parts 11n and between the radially adjacent turn parts 12n. In addition, the slit 36 in this embodiment further extends from the radially outer end of the gap between the outermost turn parts 117 and 127 and the turn parts 116 and 126 located radially inward, along the turn parts 117 and 127 at a position radially outward of the outermost turn parts 117 and 127.

In this embodiment, the slits 36 are spiral-shaped and are continuous from the inner end to the outer end in the radial direction. However, the slits 36 may be intermittently formed at positions that overlap with the radial gaps that form the spiral shape of the first planar coil 11 and the radial gaps that form the spiral shape of the second planar coil 12. In this configuration, multiple magnetic wall portions 40 are used, and multiple magnetic wall portions 40 are inserted into the corresponding slits.

(Magnetic wall portion)
3 to 5 , magnetic wall portion 40 passes through radial gaps in first planar coil 11, radial gaps in second planar coil 12, and slits 36 formed in holder 30 in a direction in which first planar coil 11 and second planar coil 12 overlap (axial direction). In particular, magnetic wall portion 40 has a spiral shape, and passes through radial gaps forming the spiral shape of first planar coil 11, radial gaps forming the spiral shape of second planar coil 12, and straddles slits 36.

The magnetic wall portion 40 includes an upper end portion 41 corresponding to one end portion in the direction (axial direction) in which the first planar coil 11 and the second planar coil 12 overlap, and a lower end portion 42 corresponding to the other end portion, and the upper end portion 41 extends in the axial direction beyond the surface of the first planar coil 11 opposite the surface facing the second planar coil 12. The lower end portion 42 is flush with the surface of the second planar coil 12 facing the magnetic shield member 20 or extends beyond this surface. In this embodiment, the lower end portion 42 extends beyond the surface of the second planar coil 12 facing the magnetic shield member 20 and contacts the magnetic shield member 20.

The magnetic wall portion 40 is magnetic, and improves coil performance by suppressing eddy current loss and leakage flux and increasing the coupling coefficient. The relative permeability of the magnetic wall portion 40 is preferably 2.0 or more, and may be 2.0 or more and 10.0 or less. The relative permeability of the magnetic wall portion 40 is more preferably 5.0 or more, and may be 5.0 or more and 10.0 or less. The relative permeability of the magnetic wall portion 40 is not particularly limited, but if it is too large, the flexibility and strength of the magnetic wall portion 40 may be undesirably impaired. Therefore, the relative permeability of the holder 30 may be 200 or less.

In addition, the magnetic wall portion 40 can effectively improve coil performance by having its upper end portion 41 extend beyond the first planar coil 11. The height of the protruding portion 41A of the magnetic wall portion 40 from the surface of the first planar coil 11 to the upper end portion 41 is not particularly limited, but may be, for example, 0.5 mm or more, or 1.0 mm or more. The higher the wall portion 35 from the surface of the first planar coil 11 to the upper end portion 41, the greater the effect of suppressing eddy current loss and the higher the coupling coefficient. On the other hand, the higher the protruding portion 41A, the more likely it is to break starting from its base. Therefore, the height of the protruding portion 41A may be, for example, 10 mm or less.

The coil performance also tends to improve as the lower end 42 of the magnetic wall portion 40 moves away from the second planar coil 12. In this embodiment, the lower end 42 contacts the magnetic shield member 20, but it does not have to be in contact. If it is not in contact, it is preferable that the lower end 42 extends beyond the midpoint of the gap between the second planar coil 12 and the magnetic shield member 20 toward the magnetic shield member 20. In this case, it is preferable that the second interlayer portion 32 includes a portion that fills the gap between the lower end 42 of the magnetic wall portion 40 and the magnetic shield member 20.

In the present embodiment, the magnetic wall portion 40 includes, as an example, a retaining material containing a resin, and a plurality or an infinite number of magnetic particles made of a magnetic material. The magnetic particles are retained by the retaining material. The retaining material is insulating, and more specifically, is non-magnetic and insulating. The retaining material is not particularly limited, and may include, for example, polyethylene or polypropylene, or may be formed from polyethylene or polypropylene. The retaining material may include, for example, fiber reinforced plastic, or may be formed from fiber reinforced plastic. More specifically, the retaining material may include, or be formed from glass fiber reinforced polyamide.

The magnetic particles may be formed from any one or more of ferrite, particularly soft magnetic materials such as ferrite, nanocrystalline magnetic materials, silicon steel, soft magnetic iron, and amorphous metals.

(Connecting terminal)
2 and 3, the first connection terminal 51 is connected to a radially outer end of the turn portion 117 of the first planar coil 11. The second connection terminal 52 is connected to a radially outer end of the turn portion 127 of the second planar coil 12. 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. The connection between the first connection terminal 51 and the turn portion 117 and the connection between the second connection terminal 52 and the turn portion 127 may be performed by ultrasonic bonding. However, the connection method is not limited, and for example, a connection using a conductive adhesive may be adopted.

<Simulation for evaluating the performance of coil component 10>
A simulation performed to evaluate the performance of the coil component 10 according to the present embodiment will be described below. The simulation was performed using Femtet (registered trademark) manufactured by Murata Software Corporation.

In the simulation described below, specific dimensional conditions were set for the first planar coil 11 and the second planar coil 12 in the coil component 10 in the above-described embodiment, and the Q value was calculated.

The present inventors have conducted intensive research to improve coil performance such as Q value and inductance while reducing the amount of magnetic material used by partially providing magnetic wall portions 40 at specific locations around the first planar coil 11 and the second planar coil 12. The inventors have found that beneficial effects can be obtained by partially providing magnetic wall portions 40 so as to pass through radial gaps in the first planar coil 11 and radial gaps in the second planar coil 12, and forming the magnetic wall portions 40 so that the upper end portion 41 of the magnetic wall portion 40 axially passes over the surface of the first planar coil 11 opposite the surface facing the second planar coil 12, and the lower end portion 42 is flush with or passes over the surface of the second planar coil 12 facing the magnetic shield member 20. In the following simulation, a coil component (Reference Example 1) having a configuration in which the lower end portion of the portion corresponding to the magnetic wall portion 40 is flush with the surface of the second planar coil 12 facing the first planar coil 11 was also simulated as a comparison target for the coil component 10.

The detailed conditions for the simulation are as follows.
The high frequency current supplied is 40A and the frequency is 85KHz.
First planar coil 11 made of copper has an electrical conductivity of 5.98×10 ⁷ S/m. Second planar coil 12 made of aluminum has an electrical conductivity of 3.77×10 ⁷ S/m.
The magnetic shield member 20 has a relative magnetic permeability of 3000, and the magnetic wall portion 40 has a relative magnetic permeability of 5.0.
First planar coil 11 has a thickness of 0.25 mm, and second planar coil 12 has a thickness of 0.50 mm.
The dimension of the gap between first planar coil 11 and second planar coil 12 is 0.50 mm, and the dimension of the gap between second planar coil 12 and magnetic shield member 20 is 1.0 mm.
The same conditions as above were set in the simulation for the reference example.

The inductance (μH) of the coil component 10 according to the first embodiment, derived based on the simulation, was 35.8, the resistance (Ω) was 0.096, and the Q value was 199.1. In contrast, the inductance (μH) of the coil component according to the reference example 1, derived based on the simulation, was 33.6, the resistance (Ω) was 0.133, and the Q value was 135.1.

It can be seen that the coil component 10 according to the embodiment has a higher inductance and Q value than reference example 1, ensuring high coil performance.

As described above, the inventors have found that when the first planar coil 11 and the second planar coil 12 are stacked on the magnetic shield member 20, the performance of the coil component 10 when used in a specified frequency band is significantly improved by setting the thickness of the first planar coil 11 to 0.15 mm or more and 0.35 mm or less. More specifically, the inventors have found that when the thickness of the first planar coil 11 is set to any value between 0.15 mm or more and 0.35 mm or less when used in a specified frequency band, the Q value of the coil component 10 becomes extremely high. The specified frequency band is specifically a frequency band of 75 KHz or more and 100 KHz or less, and the performance of the coil component 10 is reliably improved when the frequency is 79 KHz or more and 90 KHz or less.

Figure 6 is a graph showing the relationship between the thickness of the first planar coil 11 and the second planar coil 12 constituting the coil component 10 and the performance (Q value). In detail, Figure 6 shows the simulation results of the Q value of the coil component 10 when the thickness of the first planar coil 11 is changed in the range of 0.15 mm to 0.50 mm when the thickness of the second planar coil 12 is 0.25 mm or 0.50 mm. The simulation conditions are the same as those described above, and the Q value is a value when the frequency of the supply current is 85 KHz. In Figure 6, the horizontal axis indicates the thickness of the first planar coil 11, and the vertical axis indicates the Q value. Furthermore, the symbol L1 corresponds to the result when the thickness of the second planar coil 12 is fixed to 0.25 mm, and the symbol L2 corresponds to the result when the thickness of the first planar coil 11 is fixed to 0.50 mm.

In addition, the following Table 1 shows the relationship between the combinations of the thicknesses of the first planar coil 11 and the second planar coil 12 and the simulation results of the inductance, resistance, and Q value corresponding to each combination.

The simulation results in FIG. 6 and Table 1 show that the Q value reaches a maximum value when the thickness of first planar coil 11 is 0.250 mm, regardless of whether the thickness of second planar coil 12 is 0.25 mm or 0.50 mm. Furthermore, a high Q value is ensured when the thickness of first planar coil 11 is in the range of 0.15 mm to 0.35 mm.

The above simulation results support that the performance of coil component 10 when used in a specified frequency band (85 KHz) is significantly improved by setting the thickness of first planar coil 11 to 0.15 mm or more and 0.35 mm or less. The tendency for the Q value to have a maximum value when first planar coil 11 has a thickness of 0.25 mm as shown in the above simulation also occurs when the frequency of the supplied high-frequency current is in the range of 75 KHz or more and 100 KHz or less. When the thickness of first planar coil 11 is less than 0.15 mm or greater than 0.35 mm, the Q value tends to decrease. Therefore, the thickness of first planar coil 11 may be in the vicinity of the middle between 0.15 and 0.35 mm, the thickness of first planar coil 11 may be 0.20 mm or more and 0.30 mm or less, the thickness may be 0.20 mm or more and 0.275 mm or less, or the thickness may be 0.225 mm or more and 0.275 mm or less.

<Applications of coil components>
The coil component 10 according to the present embodiment can be used as a power transmitting coil in the power transmitting device 1 of the wireless power transmission system S described above, and can be used as a power receiving coil in the power receiving device 2 .

When coil component 10 is used as a power transmission coil, first connection terminal 51 and second connection terminal 52 are connected to high frequency current supply unit 1A or AC power supply as shown in FIG. 1. When high frequency current is supplied to coil component 10, the current can be passed from first connection terminal 51 to first planar coil 11 and second planar coil 12, and then passed from second connection terminal 52 to high frequency current supply unit 1A or AC power supply. Also, the current can be passed from second connection terminal 52 to second planar coil 12 and first planar coil 11, and then passed from first connection terminal 51 to high frequency current supply unit 1A or AC power supply. This allows a magnetic field including magnetic field lines along the central axis of the planar coil to be generated.

On the other hand, when coil component 10 is used as a receiving coil, a high-frequency current can be generated in first planar coil 11 and second planar coil 12 by receiving a magnetic field including magnetic field lines that pass through the inside of first planar coil 11 and second planar coil 12. This high-frequency current can then be supplied to an external device from first connection terminal 51 or second connection terminal 52.

The coil component 10 can also be used in a transformer, an antenna, and the like. For example, when the coil component 10 functions as a primary coil in a transformer, the first connection terminal 51 and the second connection terminal 52 are connected to an AC power source. Then, by supplying a high-frequency current, a magnetic flux can be supplied from the center of the planar coil to the iron core.

The coil component 10 according to the present embodiment described above includes a magnetic shield member 20 having magnetism, a first planar coil 11 overlapping the magnetic shield member 20 with a gap therebetween, a second planar coil 12 disposed between the magnetic shield member 20 and the first planar coil 11, and a magnetic wall portion 40. The magnetic wall portion 40 is passed through the radial gap of the first planar coil 11 and the radial gap of the second planar coil 12 in a direction in which the first planar coil 11 and the second planar coil 12 overlap. The upper end portion 41, which is one end of the magnetic wall portion 40 in the overlapping direction, extends beyond the surface of the first planar coil 11 opposite the surface facing the second planar coil 12, and the lower end portion 42 is flush with the surface of the second planar coil 12 facing the magnetic shield member 20 or extends beyond the surface.

In this configuration, the magnetic material can effectively improve performance. That is, in this configuration, by providing the magnetic material wall portion 40 as a magnetic material so that it passes through the radial gap of the first planar coil 11 and the radial gap of the second planar coil 12, it is possible to improve coil performance such as inductance and Q value without providing a magnetic material between the first planar coil 11 and the second planar coil 12. That is, since the coil performance can be improved efficiently while suppressing the amount of magnetic material used, the magnetic material can effectively improve the performance of the coil component 10.

Furthermore, the first planar coil 11 and the second planar coil 12 are connected in series, the second planar coil 12 contains aluminum, and the thickness of the first planar coil 11 is 0.15 mm or more and 0.35 mm or less.

This configuration makes it easier to ensure the desired performance while suppressing the increase in size, weight, and cost. Generally speaking, it is assumed that the thicker the coil, the higher the inductance of the coil tends to be. However, the present inventor has found through intensive research that such a tendency does not necessarily occur in a configuration in which a planar coil is stacked in series on a magnetic member. The present inventor has also found that when an AC current or AC magnetic field in a predetermined frequency band is supplied in a configuration in which the second planar coil 12 and the first planar coil 11 are stacked in this order on the magnetic shield member 20, the Q value becomes extremely high when the thickness of the first planar coil 11 is between 0.15 mm and 0.35 mm, regardless of the thickness of the second planar coil 12. Based on this finding, it has been found that the performance of the coil component 10 can be improved by using a first planar coil 11 with a thickness of 0.25 mm rather than a first planar coil 11 with a thickness of 0.5 mm.

That is, in the coil component 10 based on such knowledge, the thickness of the first planar coil 11 is set to 0.15 mm or more and 0.35 mm or less, so that the first planar coil 11 can be made thin. The performance of the coil component 10 can be improved as much as possible when used in a specified frequency band. This makes it possible to improve the performance of the coil component 10 while suppressing the increase in the overall size and weight of the coil component 10. When an AC current or AC magnetic field in a specified frequency band is supplied to a configuration in which the second planar coil 12 and the first planar coil 11 are stacked in this order on the magnetic shield member 20 and the holder 30, the Q value becomes extremely high when the thickness of the first planar coil 11 is between 0.15 mm and 0.35 mm or less, regardless of the thickness of the second planar coil 12. This phenomenon is difficult to predict from technical common sense. We are convinced that the above coil component invented based on such a phenomenon will have a remarkable effect that greatly contributes to improving the performance of the coil component. Furthermore, a material containing aluminum is used as the material of the second planar coil 12. This makes it possible to more effectively suppress weight increase and costs while ensuring reasonably high coil performance. Therefore, according to this embodiment, it becomes easier to ensure the desired performance while suppressing size, weight increase, and costs.

In more detail, the inventors have found that when an AC current of 75 KHz to 100 KHz, particularly 79 KHz to 90 KHz, or an AC magnetic field of 75 KHz to 100 KHz, particularly 79 KHz to 90 KHz, is supplied to the first planar coil 11 and the second planar coil 12, the Q value becomes extremely high when the thickness of the first planar coil 11 is between 0.15 mm to 0.35 mm, regardless of the thickness of the second planar coil 12. That is, a configuration in which the thickness of the first planar coil 11 is set to 0.15 mm to 0.35 mm significantly improves performance when an AC current of 75 KHz to 100 KHz, particularly 79 KHz to 90 KHz, or an AC magnetic field of 75 KHz to 100 KHz, particularly 79 KHz to 90 KHz, is supplied as an AC current or an AC magnetic field in a predetermined frequency band.

<<Second embodiment>>
A coil component 10a according to the second embodiment will be described below. Fig. 7 is a cross-sectional view of the coil component 10a according to the second embodiment. Components in this embodiment that are the same as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

In this embodiment, the slit 36 in the holder 30 is recessed in the direction from the first planar coil 11 toward the magnetic shield member 20. That is, the slit 36 does not penetrate the holder 30. As a result, the lower end 42 of the magnetic wall portion 40 inserted into the slit 36 does not contact the magnetic shield member 20. The lower end 42 of the magnetic wall portion 40 is positioned between the second planar coil 12 and the magnetic shield member 20. The second interlayer portion 32 includes a wall support portion 32A that fills the gap between the lower end 42 of the magnetic wall portion 40 and the magnetic shield member 20.

In the coil component 10a according to the second embodiment, the second interlayer portion 32 is in a sheet shape, which increases the strength of the holder 30.

<<Third embodiment>>
Hereinafter, a coil component 10b according to the third embodiment will be described. Fig. 8 is a cross-sectional view of the coil component 10b according to the third embodiment. Components in this embodiment that are the same as those in the first and second embodiments are given the same reference numerals, and descriptions thereof will be omitted.

In this embodiment, the slits 36 in the holder 30 are recessed in a direction from the first planar coil 11 toward the magnetic shield member 20. That is, the slits 36 do not penetrate the holder 30. As a result, the lower end 42 of the magnetic wall portion 40 inserted into the slits 36 does not contact the magnetic shield member 20. The lower end 42 of the magnetic wall portion 40 is flush with the surface of the second planar coil 12 that faces the magnetic shield member 20. The second interlayer portion 32 includes a wall support portion 32A that fills the gap between the lower end 42 of the magnetic wall portion 40 and the magnetic shield member 20. The coil component 10b according to the third embodiment provides the same effect as the second embodiment.

Here, the following Table 2 shows the simulation results for coil component 10a according to the second embodiment and coil component 10b according to the third embodiment. Table 2 also shows the above-mentioned simulation results for coil component 10 according to the first embodiment and the simulation results for Reference Example 1. Furthermore, Table 2 also shows the simulation results for a coil component (Reference Example 2) having a configuration in which the lower end of the portion corresponding to magnetic wall portion 40 is flush with the surface of first planar coil 11 facing second planar coil 12.

In the simulation results in Table 2, the inductance and Q value of the coil component 10a according to the second embodiment and the coil component 10b according to the third embodiment are higher than those of Reference Example 1 and Reference Example 2. This result also confirms the effectiveness of the coil component 10a according to the second embodiment and the coil component 10b according to the third embodiment.

<<Fourth embodiment>>
A coil component 10c according to the fourth embodiment will be described below. Fig. 9 is a cross-sectional view of the coil component 10c according to the fourth embodiment. Components in this embodiment that are the same as those in the first to third embodiments are given the same reference numerals, and descriptions thereof will be omitted.

In this embodiment, slits 36 in the holder 30 penetrate the holder 30 in the direction from the first planar coil 11 toward the magnetic shield member 20. The lower end of the magnetic wall portion 40 inserted into the slits 36 contacts the magnetic shield member 20. Meanwhile, there is no member between the first planar coil 11 and the second planar coil 12, and an air layer is formed. Similarly, there is no member between the second planar coil 12 and the magnetic shield member 20, and an air layer is formed.

The coil component 10c according to the fourth embodiment is advantageous in terms of suppressing dielectric breakdown or short circuit between the first planar coil 11 and the second planar coil 12. Note that the air layer may be formed only between the first planar coil 11 and the second planar coil 12 or only between the second planar coil 12 and the magnetic shield member 20.

<<Fifth embodiment>>
A coil component 10d according to a fourth embodiment will be described below. Fig. 10 is a cross-sectional view of a coil component 10d according to a fifth embodiment. Components in this embodiment that are the same as those in the first to fourth embodiments are given the same reference numerals, and descriptions thereof will be omitted.

Coil component 10d further includes an even number of other planar coils 201, 202 arranged between first planar coil 11 and second planar coil 12. In this embodiment, the even number of other planar coils 201, 202 are composed of third planar coil 201 and fourth planar coil 202. However, the even number of other planar coils may be composed of four, six, etc. planar coils.

Then, the first planar coil 11, the other planar coils 201 and 202, and the second planar coil 12 are connected in series. The thickness of at least the fourth planar coil 202 among the third planar coil 201 and the fourth planar coil 202 different from the third planar coil 201 connected to the second planar coil 12 in the other planar coils 201 and 202 is 0.15 mm or more and 0.35 mm or less. In this embodiment, the thickness of the third planar coil 201 is also 0.15 mm or more and 0.35 mm or less. Furthermore, the thickness of the first planar coil 11, the thickness of the third planar coil 201, and the thickness of the fourth planar coil 202 are the same. Note that the size of the second planar coil 12 is in the same range as in the above-mentioned embodiment, and the thickness may be, for example, 0.5 mm or more and 1.0 mm or less. Furthermore, if the thickness of third planar coil 201 is set to a value outside the range of 0.15 mm to 0.35 mm, the thickness of third planar coil 201 may be 1.0 mm or less, or may be the same as the thickness of second planar coil 12.

The coil component 10d according to this embodiment can also improve performance while suppressing increases in size and weight. More specifically, when an AC current of 75 KHz to 100 KHz, particularly 79 KHz to 90 KHz, or an AC magnetic field of 75 KHz to 100 KHz, particularly 79 KHz to 90 KHz, is supplied to the first planar coil 11, the other planar coils 201 and 202, and the second planar coil 12, the performance of the coil component 10d can be significantly improved.

In coil component 10d, magnetic wall portion 40 passes through the radial gaps in first planar coil 11, the radial gaps in each of the other planar coils 201 and 202, and the radial gaps in second planar coil 12. In this embodiment, upper end portion 41 of magnetic wall portion 40 also extends axially beyond the surface of first planar coil 11 opposite the surface facing second planar coil 12. Lower end portion 42 also becomes flush with the surface of second planar coil 12 facing magnetic shield member 20 or extends beyond that surface.

Although the embodiment of the present disclosure has been described above, various modifications may be made to the above-described embodiment. Such modifications may also be included within the technical scope of the present disclosure.

S...power transmission system 1...power transmission device 1A...high frequency current supply section 2...power receiving device 2A...conversion section 10, 10a, 10b, 10c, 10d...coil component 11...first planar coil 12...second planar coil 12n...turn section 12E...conductor 14...connection wiring section 20...magnetic shielding member 30...holding body 31...first interlayer section 32...second interlayer section 32A...wall support section 33...outer peripheral frame section 34...inner peripheral core section 36...slit 40...magnetic wall section 41...upper end section 41A...protruding section 42...lower end section 51...first connection terminal 52...second connection terminal 201...third planar coil 202...fourth planar coil C1...first central axis C2...second central axis

Claims (23)

a magnetic shield member having magnetic properties;
a first planar coil overlapping the magnetic shield member with a gap therebetween;
a second planar coil disposed between the magnetic shield member and the first planar coil;
a magnetic wall portion having magnetism, the first planar coil and the second planar coil being passed through radial gaps in the first planar coil and radial gaps in the second planar coil in a direction in which the first planar coil and the second planar coil overlap, one end of the first planar coil in the overlapping direction extending beyond a surface of the first planar coil opposite a surface that faces the second planar coil, and the other end of the second planar coil in the overlapping direction being flush with a surface of the second planar coil that faces the magnetic shield member or extending beyond the facing surface. The coil component according to claim 1, further comprising a holder including a first interlayer portion disposed between the first planar coil and the second planar coil, and a second interlayer portion disposed between the second planar coil and the magnetic shield member. the holder has a slit penetrating or recessed in a direction from the first planar coil toward the magnetic shield member,
The coil component according to claim 2 , wherein the magnetic wall portion passes through a radial gap of the first planar coil, a radial gap of the second planar coil, and the slit. The coil component according to claim 1, wherein an air layer is formed at least either between the magnetic shield member and the second planar coil or between the second planar coil and the first planar coil. The coil component according to claim 1, wherein the other end of the magnetic wall portion is in contact with the magnetic shield member. The magnetic wall portion has a spiral shape,
The coil component according to claim 1 , wherein the magnetic wall portion is passed through a gap in the radial direction that defines the spiral shape of the first planar coil and a gap in the radial direction that defines the spiral shape of the second planar coil. the first planar coil and the second planar coil are connected in series;
the second planar coil comprises aluminum;
The coil component according to claim 1 , wherein the first planar coil has a thickness of 0.15 mm or more and 0.35 mm or less. The coil component according to claim 7, wherein the thickness of the second planar coil is greater than the thickness of the first planar coil. The coil component according to claim 7, wherein the specific gravity of the first planar coil is greater than the specific gravity of the second planar coil, and the electrical conductivity of the first planar coil is greater than the electrical conductivity of the second planar coil. The coil component according to claim 9, wherein the first planar coil comprises copper. The coil component according to claim 7, wherein the first planar coil and the second planar coil are supplied with an AC current of 79 KHz or more and 90 KHz or less, or are supplied with an AC magnetic field of 79 KHz or more and 90 KHz or less. The coil component according to claim 7, wherein the thickness of the second planar coil is 0.5 mm or more and 1.0 mm or less. The coil component according to any one of claims 1 to 6, wherein the magnetic wall portion includes a resin and magnetic particles held in the resin. The coil component according to claim 13, wherein the relative permeability of the magnetic wall portion is 5.0 or more. The coil component according to any one of claims 1 to 6, wherein the magnetic shielding member includes a plate-shaped ferrite. The coil component according to any one of claims 1 to 6, wherein the relative permeability of the magnetic shielding member is 500 or more. an even number of other planar coils disposed between the first planar coil and the second planar coil;
the first planar coil, the other planar coil, and the second planar coil are connected in series;
2 . The coil component according to claim 1 , wherein a thickness of at least the different planar coil among the planar coil connected to the second planar coil in the other planar coil and the planar coil different from the second planar coil is 0.15 mm or more and 0.35 mm or less. A power transmission device comprising the coil component according to claim 1. The power transmission device according to claim 18, further comprising a high-frequency current supply unit that supplies an alternating current of 79 KHz or more and 90 KHz or less to the coil component. A power receiving device comprising the coil component according to claim 1. The power receiving device according to claim 20, further comprising a conversion unit that converts an AC current of 79 KHz or more and 90 KHz or less generated by electromagnetic induction in the coil component into a DC current. The power transmission device and the power receiving device are provided.
A power transfer system, wherein at least one of the power transmitting device and the power receiving device comprises the coil component according to claim 1 . A step of supplying an AC current of 79 KHz or more and 90 KHz or less to the coil component in a power transmission device including the coil component according to claim 1;
and receiving the magnetic field generated by the power transmitting device with a power receiving device.