Coil component, coil intermediate material, power transmission device, power receiving device, and power transmission system

Abstract

To provide a coil component, a coil intermediate material, a power transmission device, a power receiving device, and a power transmission system that are capable of improving heat dissipation performance.SOLUTION: A coil device 10 includes a coil intermediate material 10M including a planar coil 11 and a first holding member 20 that holds the planar coil 11, a second holding member 30 that sandwiches the planar coil 11 with the first holding member 20, a first magnetic shield member 40 that sandwiches the second holding member with the first holding member, a second magnetic shield member 50 that sandwiches the first magnetic shield member with the first holding member, and a sealing member 70 that is sandwiched between the first holding member and the second magnetic shield member and is disposed around or at the center of the planar coil. In a plan view, a heat exchanger 80 is formed in the area where the sealing member is disposed. The heat exchanger includes a heat absorption portion 81 that absorbs heat from the planar coil using a working fluid and a heat dissipation portion 82 that dissipates heat from the working fluid.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

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

[0003] When transmitting power contactlessly, a high-frequency current is passed through a resonant circuit including a coil. The coil may be formed in a spiral shape, as disclosed in Patent Document 1, for example. Generally, the coil is used while being housed in a hollow case. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-27112 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, it has been considered to form a case integrally with a coil and to have the case hold the coil. In other words, it has been considered to form the case as a holding member that holds the coil. In this case, the inner surface of the holding member has a shape corresponding to the shape of the coil and other components associated with the coil. For example, when the coil is formed into a spiral shape, as shown in Patent Document 1, a magnetic body is disposed between adjacent portions of the coil. For this reason, a groove is formed on the inner surface of the holding member to accommodate the tip of the magnetic body.

[0006] Such a holding member can be made using a thermoplastic material or a thermosetting material. Specifically, the holding member can be produced by heating and melting the material, fitting it into a mold having concaves and convexes corresponding to the concaves and convexes on the inner surface of the holding member, and then cooling it. A coil component having a case and a coil integrally formed in this way may be required to have improved heat dissipation performance.

[0007] The present embodiment aims to provide a coil component, a coil intermediate material, a power transmitting device, a power receiving device, and a power transfer system that are capable of improving heat dissipation performance. [Means for solving the problem]

[0008] An embodiment of the present disclosure relates to the following [1] to [8].

[0009] [1] a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the first surface and holds the planar coil; a second holding member that sandwiches the planar coil between the first holding member and the second holding member; a first magnetic shield member that sandwiches the second holding member with the first holding member; a second magnetic shield member that sandwiches the first magnetic shield member with the first holding member; a sealing member sandwiched between the first holding member and the second magnetic shield member and disposed around or at the center of the planar coil, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, A hydraulic fluid is sealed in the sealing member, a heat exchange portion is formed in a region where the sealing member is arranged in a plan view, The heat exchanger includes a heat absorbing portion that absorbs heat from the planar coil by the working fluid, and a heat dissipating portion that dissipates heat from the working fluid.

[0010] [2] The coil component according to [1], wherein the depth of the heat exchange portion increases toward the heat absorption portion.

[0011] [3] The first holding member has a rectangular shape in a plan view, The coil component according to [1] or [2], wherein the heat exchange portions are formed at four corners of the first holding member.

[0012] [4] The heat absorption portion protrudes toward the central axis, The coil component according to any one of [1] to [3], wherein the heat absorption portion overlaps the planar coil in a planar view.

[0013] [5] a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the first surface and holds the planar coil; a sealing member disposed at least either around or at the center of the planar coil, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, A hydraulic fluid is supplied into the sealing member, a heat exchange portion is formed in a region where the sealing member is arranged in a plan view, The heat exchange portion has a heat absorption portion that absorbs heat from the planar coil by the working fluid, and a heat dissipation portion that dissipates heat from the working fluid.

[0014] [6] A power transmission device comprising the coil component according to any one of [1] to [4].

[0015] [7] A power receiving device comprising the coil component according to any one of [1] to [4].

[0016] [8] The power transmission device includes a power receiving device. A power transmission 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 [4]. [Effects of the Invention]

[0017] According to the present disclosure, the heat dissipation performance of the coil component can be improved. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram schematically illustrating a wireless power transmission system to which a coil unit according to an embodiment can be applied. [Figure 2] FIG. 2 is an exploded perspective view showing the coil component according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the coil component according to the embodiment, taken along the coil axis (cross-sectional view taken along line III-III in FIG. 2). [Figure 4] FIG. 4 is a plan view showing a coil intermediate material of a coil component according to an embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing the coil component according to the embodiment, taken along the coil axis (cross-sectional view taken along line VV in FIG. 2). [Figure 6] FIG. 6 is a perspective view showing a heat exchange portion of a coil intermediate material according to one embodiment. [Figure 7] FIG. 7 is an enlarged perspective view of a heat exchange portion of a coil intermediate material according to an embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing an example of a method for manufacturing a coil component according to an embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing an example of a method for manufacturing a coil component according to an embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing an example of a method for manufacturing a coil component according to an embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing an example of a method for manufacturing a coil component according to an embodiment. [Figure 12] FIG. 12 is a cross-sectional view (a cross-sectional view corresponding to FIG. 5) showing a modified example of the coil device according to the embodiment. [Figure 13] FIG. 13 is a plan view showing a modified example of the coil device according to the embodiment. [Figure 14] FIG. 14 is a cross-sectional view showing a modified example of the coil device according to the embodiment, taken along the coil axis (cross-sectional view taken along line XIV-XIV in FIG. 13). [Figure 15] FIG. 15 is a cross-sectional view (a cross-sectional view corresponding to FIG. 14) showing a modified example of the coil device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Each embodiment will be described below with reference to the drawings. Note that in the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding.

[0020] Furthermore, 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.

[0021] Fig. 1 schematically shows a wireless power transmission system S to which a coil device 10 according to one embodiment is applied. First, the wireless power transmission system S (hereinafter abbreviated as power transmission system S) will be described with reference to Fig. 1. It goes without saying that a coil device different from the coil device 10 according to this embodiment can be applied to the power transmission system S.

[0022] <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 component. The high-frequency current supply unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil component.

[0023] 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 component. 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. The conversion unit 2A may include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0024] 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.

[0025] 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 component. 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 component in the power receiving device 2. That is, the power receiving device 2 receives the magnetic field from the power transmitting device 1 or is influenced by the magnetic field, and causes the high-frequency current to flow by electromagnetic induction. The conversion unit 2A converts this high-frequency current into a direct current and supplies the converted direct current to, for example, a battery (not shown).

[0026] 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.

[0027] 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 drones and other flying objects and robots. The power transmission system S may also be used to transmit power to underwater submersibles and exploration robots. In this way, the power transmission system S can be used to transmit power to various moving objects such as electric vehicles, flying objects, robots, and submersibles. The use of the coil component 10 is also not limited to wireless power transmission systems. For example, the coil component 10 may be used in transformers, DC-DC converters, antennas, etc.

[0028] <Coil parts> The coil device 10 will now be described. Fig. 2 is an exploded perspective view of the coil device 10. Fig. 3 is a cross-sectional view of the coil device 10 taken along a central axis C10 of a planar coil 11, which will be described later. Fig. 4 is a plan view of a coil intermediate material 10M, which will be described later.

[0029] 2, the coil device 10 includes a planar coil 11, a first holding member 20, a second holding member 30, a first magnetic shield member 40, a second magnetic shield member 50, and a sealing member 70. In the illustrated example, the coil device 10 further includes a first connection terminal 61 and a second connection terminal 62.

[0030] As shown in FIG. 2, in the coil device 10, the planar coil 11, the second holding member 30, the first magnetic shield member 40, and the second magnetic shield member 50 are stacked on the first holding member 20 in this order. The sealing member 70 is disposed on the first holding member 20, and a heat absorbing portion 81 (described later) is disposed so as to be located above the planar coil 11. In FIG. 2, the first connection terminal 61 and the second connection terminal 62 are simply indicated by two-dot chain lines. Each component of the coil device 10 will be described in detail below. As will be described later, the planar coil 11 and the first holding member 20 form a coil intermediate material 10M shown in FIG. 4. Each component of the coil device 10 will be described in detail below.

[0031] (planar coil) The planar coil 11 has a spiral shape and is made of a conductive material. In this embodiment, the planar coil 11 contains copper. Specifically, the planar coil 11 is made of copper. However, the planar coil 11 may be made of a copper alloy, aluminum, an aluminum alloy, or the like.

[0032] As shown in FIG. 2, the planar coil 11 is plate-shaped, and as shown in FIG. 3, the cross-sectional shape of the planar coil 11 in the direction in which the planar coil 11 winds around in a spiral shape, in other words, in the direction perpendicular to the direction in which the planar coil 11 extends in a spiral shape, is rectangular.

[0033] The symbol C10 in FIGS. 2 to 4 indicates a central axis passing through the center of the spiral shape of the planar coil 11. Hereinafter, the axial direction of the planar coil 11 refers to a direction extending on the central axis C10 or a direction parallel to the central axis C10. The radial direction of a circle drawn on a plane perpendicular to the central axis C10 and centered at an arbitrary point on the central axis C10 is referred to as the radial direction of the planar coil 11. The planar coil 11 includes a first surface 11A and a second surface 11B that are opposite to each other in the axial direction. The first surface 11A of the planar coil 11 faces the first holding member 20. The second surface 11B is the surface opposite to the first surface 11A and faces the second holding member 30.

[0034] As shown in Fig. 2, the 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 planar coil 11 are arranged in a direction perpendicular to the central axis C10. Specifically, the plurality of turn portions 11n are connected so as to gradually move away from the central axis C10 radially outward of the planar coil 11. This forms the spiral shape.

[0035] The turn portions 11n are basically linear conductor portions that do not form a loop but wrap around the central axis C10 360 degrees. In the case of a so-called planar coil, both ends of the turn portions 11n are offset in the radial direction of the planar coil 11. In the 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 central axis C10.

[0036] Hereinafter, the turn portion 11n that is closest to the central axis C10 may be referred to as the turn portion 1101. Furthermore, the turn portion connected to the turn portion 1101 may be referred to as the turn portion 1102. In this embodiment, the turn portions 11n include 12 turn portions 1101 to 1112. Hereinafter, when describing matters that are common to each of the turn portions 11n, they will basically be referred to as the turn portion 11n.

[0037] In this embodiment, the turn section 11n winds around to form an octagonal shape. More specifically, the turn section 11n winds around to form a regular octagonal shape. However, the turn section 11n may wind around to form a polygonal shape other than an octagonal shape. For example, the turn section 11n may wind around to form a dodecagonal shape or a regular dodecagonal shape. The turn section 11n may also wind around to form a circle. Note that the term "spiral shape" as used herein and in this disclosure refers to a planar curved shape wound in a spiral shape. The planar curved shape referred to here also includes a planar pattern that winds around repeatedly while bending like a broken line, as shown in the figure. In other words, the spiral shape refers to a planar curved shape that moves away from the center as it winds (or moves closer to the center as it winds).

[0038] The radially inner end (the end closest to the central axis C10) of the turn portion 1101 closest to the central axis C10 is electrically connected to the second connection terminal 62. On the other hand, the radially outer end (the end farthest from the central axis C10) of the turn portion 1112 of the multiple turn portions 11n that is farthest from the central axis C10 is connected to the first connection terminal 61.

[0039] Here, the radially inward direction of the planar coil 11 (turn portions 11n) refers to a direction approaching the central axis C10 in the radial direction. The radially outward direction of the planar coil 11 (turn portions 11n) refers to a direction away from the central axis C10 in the radial direction. In this embodiment, the central axis C10 is determined as follows: First, linear virtual turn portions similar in shape to the turn portions 1102 are drawn sequentially from the radially inner end of the turn portion 1102 adjacent to the innermost turn portion 1101 in a spiral shape extending radially inward. The drawing is continued until a virtual turn portion that fits within a diameter of 1 cm is drawn. A line that passes through the radially inner region of the virtual turn portion that fits within a diameter of 1 cm in a direction perpendicular to the circumferential and radial directions of the spiral shape is determined as the central axis C10.

[0040] In the present embodiment, planar coil 11 is formed by punching a metal plate such as a copper plate or an aluminum plate into a spiral shape, for example. However, planar coil 11 can also be formed by etching a metal foil such as a copper foil or an aluminum foil into a spiral shape.

[0041] The thickness of the planar coil 11 (thickness of the conductor 11E) may be, for example, 0.1 mm or more and 1.0 mm or less. The radius of the planar coil 11 (the distance from the central axis C10 to the farthest point in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less. The aspect ratio of the planar coil 11 (conductor 11E) having a rectangular cross section is determined by dividing the radial width (width in the radial direction) of the planar coil 11 (conductor 11E) by the thickness of the planar coil 11 (conductor 11E). The aspect ratio of the planar coil 11 (conductor 11E) may be 2 or more and 12 or less, or 3 or more and 10 or less.

[0042] 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 power in a high-frequency current frequency band of 10 kHz to 200 kHz, particularly 75 kHz to 100 kHz, and even more preferably 79 kHz to 90 kHz. In this case, the thickness of planar coil 11 made of copper is preferably 0.2 mm or more. From this perspective, the lower limit of the thickness of planar coil 11 may be set to 0.2 mm. Furthermore, when transmitting power to an electric vehicle, an excessively large size is not desirable, and the size may be limited. From this perspective, it is desirable for planar coil 11 (conductor 11E) to be formed to a size that fits within a square with sides of 800 mm.

[0043] Furthermore, the line width of planar coil 11 (line width of conductor 11E), i.e., the radial width of each turn portion 11n (width in the radial direction), is not particularly limited. However, considering that a power of 1 kW or more, preferably 5 kW or more, can be transmitted in a high-frequency current frequency band of, for example, 79 kHz to 90 kHz, the radial width of turn portion 11n may be 2 mm to 20 mm, 2 mm to 16 mm, 2 mm to 12 mm, or 2 mm to 8 mm. Furthermore, the number of turns of planar coil 11 is not particularly limited and may be 11 or less, or 13 or more.

[0044] (First holding member) First holding member 20 overlaps planar coil 11 so as to face first surface 11A of planar coil 11, and holds planar coil 11. In the present embodiment, first holding member 20 has a rectangular shape in a planar view and surrounds planar coil 11. In coil device 10, for example, when transmitting power, the magnetic field generated in planar coil 11 passes through first holding member 20. Therefore, first holding member 20 is preferably non-conductive (insulating) and non-magnetic so as not to interfere with the magnetic field and to prevent eddy currents from occurring.

[0045] Considering that non-conductive (insulating) and non-magnetic properties are preferable, the material of the first holding member 20 is, for example, resin, and may also be fiber reinforced plastic. More specifically, the material of the first holding member 20 may be glass fiber reinforced polyamide. However, the material of the first holding member 20 is not particularly limited. For example, it may not contain glass fiber. Also, thermoplastic resins or thermosetting resins other than polyamide may be used. Note that insulating properties are defined as those having a volume resistivity of 10 10 This means that the resistance is Ω·m or more. Non-magnetic means that it does not exhibit magnetism.

[0046] First holding member 20 is integrated with planar coil 11 to hold planar coil 11. In this embodiment, after planar coil 11 is placed in mold 202 (see FIG. 8) for forming first holding member, a material for making the first holding member is pressed into mold 202 by hot pressing to form the material, which is then cooled and solidified, thereby integrating planar coil 11 and first holding member 20. In this specification, first holding member 20 integrated with planar coil 11 is also referred to as coil intermediate material 10M.

[0047] In this embodiment, first holding member 20 sandwiches planar coil 11 with second holding member 30. As shown in FIG. 3 , first holding member 20 has a first contact surface 20S1 that contacts first surface 11A of planar coil 11 and a second contact surface 20S2 that contacts base 31 (described later) of second holding member 30. The height position (position in the coil axis direction) of first contact surface 20S1 is the same as the height position of first surface 11A of planar coil 11. The height position (position in the coil axis direction) of second contact surface 20S2 is the same as the height position of second surface 11B of planar coil 11. Contact surfaces 20S1 and 20S2 form part of the inner surface of first holding member 20. In addition, first holding member 20 has an outer surface 20S3 that is the surface opposite to contact surfaces 20S1 and 20S2.

[0048] As shown in FIGS. 3 and 4, the first holding member 20 is formed with grooves 24 that receive protrusions 32 (described later) of the second holding member 30. The grooves 24 are formed between adjacent turn portions 11n of the planar coil 11 when viewed in the axial direction of the planar coil 11. In the illustrated example, the grooves 24 are also formed radially outward of the outermost turn portion 1112. In addition, in the illustrated example, the grooves 24 are also formed radially inward of the innermost turn portion 1101. Furthermore, in the illustrated example, the grooves 24 are formed along the spiral shape of the planar coil 11 (see FIG. 4). Therefore, the grooves 24 are formed in a spiral shape that corresponds to the spiral shape of the planar coil 11.

[0049] (Second holding member) 3 , second holding member 30 in this embodiment is integrated with planar coil 11 and first holding member 20 so as to sandwich planar coil 11 between them. In this embodiment, second holding member 30 has a rectangular shape in a planar view and surrounds planar coil 11. Second holding member 30 is interposed between planar coil 11 and first magnetic shield member 40.

[0050] Specifically, the second holding member 30 has a base 31 interposed between the planar coil 11 and the first magnetic shield member 40, and a protrusion 32 protruding from the base 31 toward the first holding member 20. The base 31 entirely covers the second surface 11B of the planar coil 11. When viewed in the axial direction of the planar coil 11, the base 31 is formed to a size sufficient to encompass the entire planar coil 11. The base 31 and the first holding member 20 sandwich the planar coil 11 therebetween. In the illustrated example, the base 31 contacts the second surface 11B of the planar coil 11. However, another layer may be disposed between the base 31 and the second surface 11B of the planar coil 11.

[0051] The protrusions 32 extend between adjacent turn portions 11n of the planar coil 11 along the axial direction of the planar coil 11. Therefore, the protrusions 32 are formed along the spiral-shaped planar coil 11. In the illustrated example, the protrusions 32 are formed in a spiral shape corresponding to the spiral shape of the planar coil 11. As described above, the protrusions 32 are received in the grooves 24 of the first holding member 20. In other words, the protrusions 32 fill the grooves 24 of the first holding member 20. In the illustrated example, the protrusions 32 are also formed radially outward from the outermost turn portion 1112. Furthermore, the protrusions 32 are also formed radially inward from the innermost turn portion 1101.

[0052] The second holding member 30 is magnetic as a whole. That is, the base 31 and the protrusion 32 are both magnetic. The second holding member 30 uses its magnetism to suppress eddy current loss and leakage flux, and to increase the coupling coefficient, thereby improving coil performance. The relative permeability of the second holding member 30 is preferably 2.0 or more, and may be 2.0 to 10.0. The relative permeability of the second holding member 30 is more preferably 5.0 or more, and may be 5.0 to 10.0. The relative permeability of the second holding member 30 is not particularly limited, but if it is too high, the flexibility and strength of the second holding member 30 may be undesirably impaired. Therefore, the relative permeability of the second holding member 30 may be 200 or less.

[0053] Furthermore, the provision of the protrusion 32 on the second holding member 30 can effectively improve coil performance. The height of the protrusion 32 (the distance between the top of the protrusion 32 and the second surface 11B of the planar coil 11 along the axial direction of the planar coil 11) is not particularly limited, but may be, for example, 0.5 mm or more, or 1.0 mm or more. The higher the protrusion 32, the greater the effect of suppressing eddy current loss and the higher the coupling coefficient tend to be. On the other hand, the higher the protrusion 32, the more likely it is that it will break starting from its base. Therefore, the height of the protrusion 32 may be, for example, 10 mm or less.

[0054] The second holding member 30 in this embodiment includes, for example, a resin and a plurality or an infinite number of magnetic particles made of a magnetic material. The magnetic particles are held by the resin as a holding material.

[0055] The magnetic particles may be made of one or more of ferrite, particularly soft magnetic ferrite, nanocrystalline magnetic material, silicon steel, soft electromagnetic iron, and amorphous metal. The resin used as the holding material may be glass fiber reinforced polyamide. That is, the resin may be made of a material containing polyamide as a thermoplastic resin (thermoplastic material) and glass fiber. However, the molding material of the second holding member 30 is not particularly limited.

[0056] (First magnetic shield member) The first magnetic shield member 40 is provided to suppress magnetic transmission and / or leakage magnetic field. In this embodiment, the first magnetic shield member 40 sandwiches the planar coil 11 and the second holding member 30 with the first holding member 20. The first magnetic shield member 40 is a sheet-like member separate from the planar coil 11, the first holding member 20, and the second holding member 30. The fact that the first magnetic shield member 40 is separate from the planar coil 11, the first holding member 20, and the second holding member 30 means that the first magnetic shield member 40 is not integrated with the planar coil 11, the first holding member 20, and the second holding member 30. However, the first magnetic shield member 40 and the second holding member 30 may be joined via an adhesive layer or the like. The first magnetic shield member 40 is formed to a size that encompasses the planar coil 11 and the second holding member 30 in a planar view. The first magnetic shield member 40 overlaps the planar coil 11 and the second holding member 30. The first magnetic shield member 40 may be in direct contact with the second holding member 30. Alternatively, another layer made of a heat dissipation material or the like may be disposed between the first magnetic shield member 40 and the second holding member 30.

[0057] In this embodiment, the first magnetic shield member 40 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 planar coil 11. The magnetic field generated by the coil component 10 spreads in all directions relative to the central axis C10 of the planar coil 11. In this case, the first magnetic shield member 40, being magnetic, can orient the spreading magnetic flux lines toward the central axis C10. Furthermore, the coil component 10 may be installed in a vehicle. In this case, if the magnetic field generated by the coil component 10 flows toward other vehicle components, it may adversely affect the vehicle components. In such cases, the first magnetic shield member 40 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0058] The first magnetic shield member 40 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the first magnetic shield member 40 includes a ferrite, preferably a soft ferrite.

[0059] The relative permeability of the first magnetic shield member 40 may be equal to or greater than 500, or may be equal to or greater than 1000. The relative permeability of the first magnetic shield member 40 may be equal to or greater than 500 and equal to or greater than 3000, or may be equal to or greater than 1000 and equal to or less than 3000. Note that the relative permeability in this specification is a value measured at a frequency of 85 kHz and an ambient temperature of 23 degrees.

[0060] (Second magnetic shield member) The second magnetic shield member 50 is disposed to cover the first magnetic shield member 40. In this embodiment, the second magnetic shield member 50 sandwiches the first magnetic shield member 40, the planar coil 11, the second holding member 30, and the sealing member 70 with the first holding member 20. The second magnetic shield member 50 may be in direct contact with the first magnetic shield member 40. Alternatively, another layer formed of a heat dissipation material or a spacer may be disposed between the second magnetic shield member 50 and the first magnetic shield member 40. The second magnetic shield member 50 is formed of a metallic material and is conductive. Specifically, the second magnetic shield member 50 in this embodiment is formed of aluminum. In this case, magnetic leakage from the planar coil 11 through the second magnetic shield member 50 is suppressed. The second magnetic shield member 50 may be formed of an aluminum alloy, copper, stainless steel, or the like. When the coil device 10 is attached to an automobile, the second magnetic shield member 50 may be a metal plate constituting the automobile body.

[0061] (Sealing member) 2 and 5, the sealing member 70 is sandwiched between the first holding member 20 and the second magnetic shield member 50. Furthermore, as shown in FIGS. 2 and 4, the sealing member 70 is disposed around the planar coil 11. The sealing members 70 are disposed at the four corners of the first holding member 20.

[0062] 6, the sealing member 70 has a first side 71 along one side of the rectangle formed by the first holding member 20, a second side 72 along the other side connected to the first side, and a third side 73 connecting the first side 71 and the second side 72. Of these, a protruding portion 74 protruding toward the central axis C10 is formed on the third side 73. This protruding portion 74 constitutes a heat absorbing portion 81 of a heat exchanger 80, which will be described later.

[0063] 6 and 7, the sealing member 70 has a first protruding wall 75, an O-ring 76, and a second protruding wall 77. The first protruding wall 75, the O-ring 76, and the second protruding wall 77 are arranged in this order from the inside to the outside of the space surrounded by the sealing member 70 in a plan view. The first protruding wall 75, the O-ring 76, and the second protruding wall 77 are provided around the entire periphery of the sealing member 70. The first protruding wall 75 may be formed integrally with the first holding member 20.

[0064] For example, the second protruding wall 77 may include a resin and a plurality or countless magnetic particles made of a magnetic material. The magnetic particles are held in the resin as a holding material. The magnetic particles may be made of one or more of ferrite, particularly soft magnetic materials, nanocrystalline magnetic material, silicon steel, soft magnetic iron, and amorphous metal. The resin as a holding material may be glass fiber reinforced polyamide. That is, the resin may be made of a material containing polyamide as a thermoplastic resin (thermoplastic material) and glass fiber. However, the molding material of the second protruding wall 77 is not particularly limited.

[0065] In such a coil component 10 (coil intermediate material 10M), a working fluid is enclosed (supplied) within the sealing member 70. A heat exchange section 80 is formed in the area where the sealing member 70 is arranged in a plan view. In this embodiment, the heat exchange section 80 is sealed as a sealed space by the first holding member 20, the second holding member 30, the second magnetic shield member 50, and the sealing member 70. Examples of the working fluid include pure water, ethanol, methanol, and acetone.

[0066] (Heat exchange part) As shown in FIG. 4, the heat exchanger 80 is formed at the four corners of the first holding member 20. As shown in FIGS. 4 to 6, the heat exchanger 80 has a heat absorbing section 81 that absorbs heat from the planar coil 11 using the working fluid, and a heat dissipating section 82 that dissipates heat from the working fluid. Of these, the heat absorbing section 81 protrudes toward the central axis C10. The heat absorbing section 81 overlaps the planar coil 11 in a planar view. This allows the heat absorbing section 81 to efficiently absorb heat from the planar coil 11. On the other hand, the heat dissipating section 82 is a section that dissipates the heat absorbed by the heat absorbing section 81.

[0067] 5 and 6, the depth of the heat exchange section 80 becomes deeper toward the heat absorption section 81. This makes it easier for the working fluid to flow toward the heat absorption section 81. In this embodiment, a depth adjustment member 83 is disposed in the space surrounded by the sealing member 70. This depth adjustment member 83 adjusts the depth of the heat exchange section 80 so that it becomes deeper toward the heat absorption section 81. In the illustrated example, the depth adjustment member 83 is disposed on the first holding member 20. This depth adjustment member 83 may be formed integrally with the first holding member 20.

[0068] Further, the depth adjusting member 83 may be formed with a notch 84 that connects to the heat absorbing portion 81. This allows the working fluid to be stored in the notch 84. Therefore, the liquid working fluid can be efficiently supplied to the heat absorbing portion 81.

[0069] (Connection terminal) 2, the first connection terminal 61 is connected to a radially outer end of the turn portion 1112 of the planar coil 11. The second connection terminal 62 is connected to a radially inner end of the turn portion 1101 of the planar coil 11. The first connection terminal 61 and the second connection terminal 62 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 61 and the turn portion 1112 and the connection between the second connection terminal 62 and the turn portion 1101 may be performed by ultrasonic bonding. However, the connection method is not limited thereto, and for example, a conductive adhesive may be used for connection.

[0070] <Method of manufacturing the coil component 10> Next, an example of a method for manufacturing the coil device 10 will be described.

[0071] First, molds 201 and 202 shown in Fig. 8 are prepared. Of these, mold 202 has a main body 203 and a protruding portion 204 extending from main body 203. Protruding portion 204 has a spiral shape corresponding to the spiral shape of groove 24. Therefore, protruding portion 204 corresponds to the shape of the gap extending between adjacent turn portions 11n of planar coil 11.

[0072] 9, the planar coil 11 is placed on the main body 203 of the mold 202. At this time, the planar coil 11 is placed on the main body 203 so that the protrusions 204 of the mold 202 extend from between the adjacent turn portions 11n of the planar coil 11.

[0073] Also, a material 220 for producing a first holding member is prepared. In the illustrated example, the material 220 is a molding material formed into a plate shape as a whole. Next, the molding material 220 is heated, and as shown in FIG. 9, the molding material 220 is placed on a mold 202 and a planar coil 11. Next, as shown in FIG. 10, the planar coil 11 and the molding material 220 are heat-pressed between the mold 202 and another mold 201.

[0074] The molding material 220 softens and melts between the molds 201 and 202. As a result, grooves 24 corresponding to the protrusions 204 of the mold 202 are formed on one surface of the molding material 220. In this manner, the first holding member 20 having the grooves 24 is formed. As viewed in the coil axial direction, the grooves 24 are formed between adjacent turn portions 11n of the planar coil 11. Furthermore, as the first holding member 20 cools and solidifies, the first holding member 20 and the planar coil 11 are integrated together. At this time, the first protruding wall 75 of the sealing member 70 may also be formed. In this manner, the coil intermediate material 10M shown in FIG. 4 is produced.

[0075] After the coil intermediate material 10M is removed from the molds 201 and 202, as shown in FIG. 11 , the second holding member 30 is formed on the coil intermediate material 10M (more specifically, on the second surface 11B of the planar coil 11). At this time, the groove 24 is filled with the second holding member 30. The second holding member 30 is integrated with the coil intermediate material 10M. At this time, the second protruding wall 77 of the sealing member 70 may also be formed. Thereafter, an O-ring 76 is attached between the first protruding wall 75 and the second protruding wall 77. Then, the first magnetic shield member 40 and the second magnetic shield member 50 are arranged on the second holding member 30. In this manner, the coil device 10 is manufactured.

[0076] <Applications of coil components> 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 described above, and can also be used as a power receiving coil in the power receiving device 2.

[0077] When the coil component 10 is used as a power transmission coil, the first connection terminal 61 and the second connection terminal 62 are connected to the high-frequency current supply unit 1A or AC power supply as shown in FIG. 1. When a high-frequency current is supplied to the coil component 10, the current can flow from the first connection terminal 61 to the planar coil 11, and then from the second connection terminal 62 to the high-frequency current supply unit 1A or AC power supply. Alternatively, the current can flow from the second connection terminal 62 to the planar coil 11, and then from the first connection terminal 61 to the high-frequency current supply unit 1A or AC power supply. This allows a magnetic field including magnetic field lines along the central axis of the planar coil to be generated.

[0078] On the other hand, when the coil component 10 is used as a receiving coil, a high-frequency current can be generated in the planar coil 11 by receiving or generating a magnetic field including magnetic lines of force that pass through the inside of the planar coil 11. Then, this high-frequency current can be supplied to an external device from the first connection terminal 61 or the second connection terminal 62.

[0079] The coil component 10 can also be used in a transformer, an antenna, etc. For example, when the coil component 10 functions as a primary coil of a transformer, the first connection terminal 61 and the second connection terminal 62 are connected to an AC power source. When a high-frequency current is supplied, magnetic flux can be supplied from the center of the planar coil to the iron core.

[0080] <Coil component cooling method> Next, a method for cooling the coil component 10 will be described.

[0081] When such a coil component 10 is used, the planar coil 11 generates heat. When the planar coil 11 generates heat, the working fluid present in the heat absorbing section 81 receives heat from the planar coil 11. The received heat is absorbed as latent heat, and the working fluid evaporates, generating working vapor. The generated working vapor diffuses within the heat exchange section 80. More specifically, the working vapor diffuses in a direction away from the heat absorbing section 81.

[0082] The working steam that leaves the heat absorption section 81 is transported to the heat dissipation section 82, which is a relatively low-temperature area. In the heat dissipation section 82, the working steam is cooled by dissipating heat mainly to the first holding member 20 and the second magnetic shield member 50. The heat that the first holding member 20 and the second magnetic shield member 50 receive from the working steam is transferred to the outside air.

[0083] The working steam loses the latent heat absorbed in the heat absorption section 81 by radiating heat to the first holding member 20, etc. in the heat radiating section 82. As a result, the working steam condenses and a working fluid is generated. In this embodiment, the depth of the heat exchange section 80 increases toward the heat absorbing section 81. Therefore, the generated working fluid flows toward the heat absorbing section 81. In this way, the evaporation of the working fluid and the condensation of the working steam are repeated, thereby cooling the coil component 10.

[0084] <Modification> Various modifications can be made to the above-described embodiment. For example, coil component 10 includes two planar coils 11, but is not limited to this. The number of planar coils included in coil component 10 may be one, or may be three or more.

[0085] Furthermore, the coil component 10 includes, but is not limited to, a plate-shaped planar coil 11 whose cross-sectional shape in the direction in which the planar coil 11 winds in a spiral shape is rectangular. The planar coil 11 does not have to be plate-shaped. The coil component 10 may also include a planar coil formed of a Litz wire. A Litz wire is formed by twisting together multiple conductor wires. In this case, the cross-sectional shape of the planar coil in the direction in which the planar coil winds in a spiral shape may be circular.

[0086] Furthermore, the sealing member 70 has a first side 71 along one side of the rectangle formed by the first holding member 20, a second side 72 along the other side connected to the first side, and a third side 73 connecting the first side 71 and the second side 72, but is not limited to this. For example, as shown in Fig. 12, the sealing member 70 may be a pouch in which a working fluid is sealed. This pouch may be made of a heat-resistant resin.

[0087] Furthermore, although the sealing member 70 is disposed around the planar coil 11, this is not limiting. For example, as shown in Fig. 13, the sealing member 70 may be disposed at the center of the planar coil 11. In this case, the protruding portion 74 may protrude in a direction away from the central axis C10. Note that in Fig. 13, the first magnetic shield member 40 and the second magnetic shield member 50 are not shown in order to clarify the drawing.

[0088] As shown in FIG. 14, even when the sealing member 70 is disposed at the center of the planar coil 11, the depth of the heat exchange section 80 may become deeper toward the heat absorption section 81. In this modification, the depth of the heat exchange section 80 may be adjusted by the depth adjustment member 83 so that it becomes deeper toward the heat absorption section 81. Although not shown, the depth adjustment member 83 may have the above-mentioned notch 84 formed therein. Furthermore, as shown in FIG. 15, the sealing member 70 may be a pouch in which a working fluid is sealed. Furthermore, although not shown, the sealing member 70 may be disposed both around and at the center of the planar coil 11.

[0089] Furthermore, the depth of the heat exchange section 80 increases toward the heat absorption section 81, but is not limited to this. For example, although not shown, grooves through which the working fluid passes may be formed in the heat exchange section 80. Then, the working fluid may be transported to the heat absorption section 81 by capillary action of the grooves.

[0090] The coil device 10 according to the embodiment described above includes a spiral-shaped planar coil 11 including a first surface 11A and a second surface 11B that are opposite each other in an axial direction extending along a central axis C10 of the spiral shape, a first holding member 20 that overlaps the planar coil 11 so as to face the first surface 11A and holds the planar coil 11, a second holding member 30 that sandwiches the planar coil 11 between the first holding member 20, a first magnetic shield member 40 that sandwiches the second holding member 30 between the first holding member 20, a second magnetic shield member 50 that sandwiches the first magnetic shield member 40 between the first holding member 20, and a sealing member 70 that is sandwiched between the first holding member 20 and the second magnetic shield member 50 and is disposed around the planar coil 11. The planar coil 11 includes a plurality of turn portions 11n arranged in a radial direction of the planar coil 11. A working fluid is sealed within the sealing member 70. A heat exchange section 80 is formed in the area where the sealing member 70 is arranged in a plan view. The heat exchange section 80 has a heat absorption section 81 that absorbs heat from the planar coil 11 by the working fluid, and a heat dissipation section 82 that dissipates heat from the working fluid. With such a coil component 10, the coil component 10 is cooled by repeated evaporation of the working fluid and condensation of the working vapor. Therefore, the heat generated in the coil component 10 can be effectively removed.

[0091] In the embodiment described above, the depth of the heat exchange section 80 increases toward the heat absorption section 81. This allows the produced working fluid to flow smoothly toward the heat absorption section 81.

[0092] In the embodiment described above, the heat exchanger 80 is formed at the four corners of the first holding member 20. This allows the heat exchanger 80 to effectively remove the heat generated by the planar coil 11.

[0093] Furthermore, in the embodiment described above, the heat absorbing portion 81 protrudes toward the central axis C10. In plan view, the heat absorbing portion 81 overlaps the planar coil 11. This allows the heat absorbing portion 81 to effectively absorb the heat of the planar coil 11.

[0094] The coil intermediate material 10M according to the embodiment described above includes a spiral-shaped planar coil 11 including a first surface 11A and a second surface 11B that are opposite each other in an axial direction extending on a central axis C10 of the spiral shape, a first holding member 20 that overlaps the planar coil 11 so as to face the first surface 11A and holds the planar coil 11, and a sealing member 70 that is arranged around the planar coil 11. The planar coil 11 includes a plurality of turn portions 11n arranged in the radial direction of the planar coil 11. A heat exchanger 80 to which a working fluid is supplied is formed in a space surrounded by the sealing member 70 in a planar view. The heat exchanger 80 includes a heat absorption portion 81 that absorbs heat from the planar coil 11 by the working fluid and a heat dissipation portion 82 that dissipates heat from the working fluid. With this coil intermediate material 10M, the coil component 10 is cooled by repeated evaporation of the working fluid and condensation of the working vapor. This allows the heat generated in the coil component 10 to be effectively removed.

[0095] The power transmitting device 1 and / or the power receiving device 2 according to the embodiment and its modification described above includes the coil component 10 described above.

[0096] The power transmission system S according to the embodiment and its modification described above includes a power transmitting device 1 and a power receiving device 2. At least one of the power transmitting device 1 and the power receiving device 2 includes the coil component 10 described above.

[0097] Although several modifications of the above-described embodiment have been described, it is of course possible to combine a plurality of modifications as appropriate. [Explanation of symbols]

[0098] 1 Power transmission equipment 1A high frequency current supply 2. Power receiving device 2A conversion unit 10 Coil parts 10M coil intermediate material 11 Planar coil 11A First Side 11B Second Side 11n Turn section 11E Conductor 20 First holding member 24 groove 30 second holding member 31 Base 32 Protrusion 40 First magnetic shield member 50 second magnetic shield member 61 First connection terminal 62 Second connection terminal 70 Sealing member 80 Heat exchange section 81 Heat absorption part 82 Heat radiation part 83 Depth adjustment member 84 Notch 201 Mold 202 Mold 203 Main body 204 Convex 220 Molding materials C10 center axis S Power Transmission System

Claims

1. a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the first surface and holds the planar coil; a second holding member that sandwiches the planar coil between the first holding member and the second holding member; a first magnetic shield member that sandwiches the second holding member with the first holding member; a second magnetic shield member that sandwiches the first magnetic shield member with the first holding member; a sealing member sandwiched between the first holding member and the second magnetic shield member and disposed around or at the center of the planar coil, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, A hydraulic fluid is sealed in the sealing member, a heat exchange portion is formed in a region where the sealing member is arranged in a plan view, The heat exchanger includes a heat absorbing portion that absorbs heat from the planar coil by the working fluid, and a heat dissipating portion that dissipates heat from the working fluid.

2. The coil component according to claim 1 , wherein the depth of the heat exchange portion increases toward the heat absorption portion.

3. The first holding member has a rectangular shape in a plan view, The coil component according to claim 1 , wherein the heat exchange portions are formed at four corners of the first holding member.

4. The heat absorption portion protrudes toward the central axis, The coil component according to claim 1 , wherein the heat absorption portion overlaps the planar coil in a planar view.

5. a planar coil having a spiral shape and including a first surface and a second surface that are opposite to each other in an axial direction extending on a central axis of the spiral shape; a first holding member that overlaps the planar coil so as to face the first surface and holds the planar coil; a sealing member disposed at least either around or at the center of the planar coil, the planar coil includes a plurality of turn portions arranged in a radial direction of the planar coil, A hydraulic fluid is supplied into the sealing member, a heat exchange portion is formed in a region where the sealing member is arranged in a plan view, The heat exchange portion has a heat absorption portion that absorbs heat from the planar coil by the working fluid, and a heat dissipation portion that dissipates heat from the working fluid.

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

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

8. 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 .

Images