Coil unit

Abstract

This coil unit (10, 10A, 10B, 10C, 10D) comprises: a substrate (12); a cover (11, 11A, 11C, 11D) that forms a sealed space between said cover and the substrate; a magnetic plate (13, 13A, 13B, 13C) that is placed on the substrate in the sealed space; a coil (112, 212) that is for transmitting or receiving alternating-current power and is placed on the magnetic plate in the lamination direction in the sealed space; and a flowable substance sealed in the sealed space and having fluidity.

Description

Coil unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-207670, filed on December 8, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a coil unit.

[0003] A coil unit used in a contactless power transfer system that transfers power from a power transmitting device to a vehicle equipped with a power receiving device is known. The coil unit described in Patent Document 1 houses a device in a device housing space defined by a base and a protective cover, and external forces acting on the protective cover are received by the device in contact with the protective cover, thereby suppressing deformation of the protective cover.

[0004] JP 2017-38436 A

[0005] However, the coil unit described in Patent Document 1 has a risk of being damaged by an external force applied to the equipment. Furthermore, there is a risk of deformation occurring when an external force is applied to a portion of the protective cover that is not in contact with the equipment. Therefore, there is a need for a technology that can suppress deformation of the protective cover while suppressing deformation of the equipment housed in the protective cover.

[0006] The present disclosure can be realized in the following forms.

[0007] According to one aspect of the present disclosure, there is provided a coil unit for use in a contactless power supply system, the coil unit including: a substrate; a cover forming an enclosed space between the substrate and the cover; a magnetic plate placed on the substrate within the enclosed space; a coil for transmitting or receiving AC power, the coil being placed on the magnetic plate in a stacking direction within the enclosed space; and a fluid material having fluidity and sealed in the enclosed space.

[0008] According to this type of coil unit, since the fluid material is enclosed in the sealed space, when the cover is deformed by an external force, the volume of the sealed space contracts, the pressure of the fluid material increases, and a force that resists the contraction of the volume of the sealed space acts from inside the cover. Therefore, it is possible to suppress deformation of the cover due to the external force while suppressing deformation due to the external force acting locally on the equipment housed in the sealed space.

[0009] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an explanatory diagram showing a schematic configuration of a contactless power supply system of a first embodiment, Fig. 2 is an explanatory diagram showing a circuit configuration of the contactless power supply system of the first embodiment, Fig. 3 is an exploded perspective view showing an internal configuration of a coil unit of the first embodiment, Fig. 4 is a plan view schematically showing the coil unit of the first embodiment, Fig. 5 is a cross-sectional view taken along line V-V of Fig. 4 schematically showing the coil unit of the first embodiment, and Fig. 6 is a circuit configuration of a contactless power supply system of a second embodiment. FIG. 7 is a plan view schematically showing the coil unit of the second embodiment, FIG. 8 is a cross-sectional view taken along line VI-VI of FIG. 7, schematically showing the coil unit of the second embodiment, FIG. 9 is a cross-sectional view schematically showing the coil unit of the third embodiment, FIG. 10 is an explanatory diagram showing an enlarged view of a portion of FIG. 9, FIG. 11 is a cross-sectional view schematically showing the coil unit of the fourth embodiment, and FIG. 12 is a cross-sectional view schematically showing the coil unit of the fifth embodiment.

[0010] A. First Embodiment: A1. Configuration of Contactless Power Transfer System 300: A coil unit 10 of the first embodiment will be described with reference to Figs. 1 to 5. The coil unit 10 of the first embodiment is used in a contactless power transfer system 300. As shown in Fig. 1, the contactless power transfer system 300 includes a power transmitter 100 installed on a road RS and a power receiver 205 mounted on a vehicle 200. The contactless power transfer system 300 is a system that can supply power from the power transmitter 100 to the power receiver 205 of the vehicle 200 in a contactless manner. In this embodiment, the coil unit 10 is provided in the power transmitter 100.

[0011] The power transmitter 100 of this embodiment includes a coil unit 10 and a power supply circuit 130. The coil unit 10 includes a power transmission resonant circuit 110 and a power transmission circuit 120. In this embodiment, the coil unit 10 and the power supply circuit 130 are embedded inside the road RS. A plurality of coil units 10 may be provided, for example, arranged continuously along the extension direction of the road RS, which is the traveling direction of the vehicle 200. The coil unit 10 and the power supply circuit 130 do not necessarily need to be embedded inside the road RS. For example, they may be provided in a position on the road RS that does not interfere with the travel of the vehicle 200. The power supply circuit 130 is preferably provided near the coil unit 10. Note that the power transmission resonant circuit 110 and the power transmission circuit 120 may be configured separately from the coil unit 10.

[0012] The power supply circuit 130 supplies AC power from an AC power source such as a grid power supply to the power transmission circuit 120 via a power cable. The power transmission circuit 120 is an AC conversion circuit having a rectifier circuit, an inverter circuit, a filter circuit, etc. The power transmission circuit 120 converts the AC power supplied from the power supply circuit 130 into DC power, converts the DC power into high-frequency AC power that can be transmitted to the power receiver 205 of the vehicle 200, and supplies the DC power to the power transmission resonant circuit 110.

[0013] 2, the power transmitting resonant circuit 110 is an LC circuit in which a power transmitting side capacitor 116 functioning as a resonant capacitor and a power transmitting coil 112 are connected in series. Note that the power transmitting coil 112 and the power transmitting side capacitor 116 may be connected in parallel. The power transmitting resonant circuit 110 transmits AC power induced in the power transmitting coil 112 to the power receiving resonant circuit 210 by utilizing the electromagnetic induction phenomenon. The power transmitting coil 112 is included in the coil unit 10 of this embodiment.

[0014] The vehicle 200 is configured as a vehicle equipped with a drive motor, such as an electric vehicle or a hybrid vehicle. As shown in Fig. 1 , the vehicle 200 includes a power receiver 205 and a battery 230. The power receiver 205 includes a power receiving resonance circuit 210 and a power receiving circuit 220. Note that the vehicle 200 is not limited to an automobile, and may also be configured as a transport robot such as an AGV (Automatic Guided Vehicle) or an AMR (Autonomous Mobile Robot).

[0015] 2 , the power receiving resonant circuit 210 includes a power receiving-side capacitor 216 that functions as a resonant capacitor, and a power receiving coil 212. The power receiving resonant circuit 210 is disposed, for example, on the bottom surface of the vehicle 200. The power receiving resonant circuit 210 receives, from the power receiving coil 212, AC power induced in the power transmitting resonant circuit 110 of the power transmitter 100.

[0016] The power receiving circuit 220 converts the AC power output from the power receiving resonant circuit 210 into DC power. The power receiving circuit 220 includes, for example, a filter circuit, a rectifier circuit that converts the AC power into DC power, and a power conversion circuit that converts the AC power into DC power suitable for charging the battery 230. The battery 230 is, for example, a secondary battery that outputs DC power for driving a drive motor that is the drive source of the vehicle 200. The DC power output from the power receiving circuit 220 can be used to charge the battery 230. The DC power from the power receiving circuit 220 may also be used to charge an auxiliary battery (not shown) or to drive the drive motor or auxiliary equipment.

[0017] A-2. Configuration of the coil unit 10: Next, the configuration of the coil unit 10 will be described with reference to Fig. 3. As shown in Fig. 3, the coil unit 10 includes a cover 11, an aluminum plate 12, a ferrite plate 13, and a power transmitting coil 112. Note that Fig. 3 only illustrates the power transmitting coil 112 of the power transmitting resonant circuit 110 and the power transmitting circuit 120, and does not illustrate the other components. The coil unit 10 may also include, for example, any other components included in the power transmitting resonant circuit 110, the power transmitting circuit 120, and the power supply circuit 130.

[0018] The coil unit 10 further includes a partition plate 31 (see FIG. 4). However, the detailed configuration of the partition plate 31 will be described with reference to the figures from FIG. 4 onward, and is not shown in FIG. 3. The through-holes 41 of the ferrite plate 13 are also not shown.

[0019] The cover 11 is cup-shaped and has a rectangular appearance in a plan view. The cover 11 and the aluminum plate 12 are fitted together via a sealing member (not shown), thereby forming an enclosed space that accommodates the power transmission coil 112, the ferrite plate 13, and the aluminum plate 12. An O-ring, a liquid gasket, or the like may be used as the sealing member. Within the enclosed space, the ferrite plate 13 is placed on the aluminum plate 12, and the power transmission coil 112 is placed on the aluminum plate 12. In the following description, the direction in which the aluminum plate 12, the ferrite plate 13, and the power transmission coil 112 are stacked is also referred to as the "stacking direction." Furthermore, when the cover 11 is positioned on the top, the upper surface of each component in the stacking direction is also referred to as the "upper surface," and the lower surface in the stacking direction is also referred to as the "lower surface."

[0020] The cover 11 is non-conductive and is made of a non-magnetic material such as resin. By making the cover 11 of a non-magnetic material, it is possible to reduce or prevent blocking of the magnetic flux generated from the power transmission coil 112. The upper surface of the cover 11 is the surface of the coil unit 10 that faces the power receiving coil 212 of the vehicle 200. The lower surface of the cover 11 covers the upper surface of the power transmission coil 112 and protects the power transmission coil 112 from the outside air, etc. In this embodiment, the cover 11 is buried in the road RS, but it may also be exposed from the road RS.

[0021] The aluminum plate 12 has a rectangular external shape in a plan view. The aluminum plate 12 is provided with its upper surface abutting the lower surface of the ferrite plate 13. The aluminum plate 12 is made of aluminum or an aluminum alloy. The aluminum plate 12 dissipates heat generated in the power transmission coil 112. The aluminum plate 12 also has a shielding function to prevent magnetic flux generated from the power transmission coil 112 from escaping to the outside. Note that instead of the aluminum plate 12, a plate member for heat dissipation and shielding may be formed using a copper or other metal plate. The aluminum plate 12 corresponds to the "substrate" in this disclosure.

[0022] The ferrite plate 13 has a rectangular external shape in a plan view. The power transmitting coil 112 is placed on the upper surface of the ferrite plate 13. In this embodiment, the ferrite plate 13 is provided in contact with the lower surface of the power transmitting coil 112; however, the ferrite plate 13 may be provided spaced apart from the lower surface of the power transmitting coil 112. The ferrite plate 13 corresponds to the "magnetic plate" in this disclosure. Note that instead of the ferrite plate 13, a plate made of a dust core or a nanocrystalline soft magnetic material may be used as the magnetic plate.

[0023] In this embodiment, the power transmitting coil 112 is formed by winding a conductor such as a magnet wire around the central axis CX. The power transmitting coil 112 may also be formed by resin molding the coiled magnet wire. The power transmitting coil 112 may also be, for example, a spiral coil formed by cutting a conductor into a spiral shape, or may be various other coils such as a helical coil formed by winding a conductor having a circular or rectangular cross section in a spiral shape. When a conductor is used for the power transmitting coil 112, the conductor may be formed of a twisted wire.

[0024] The power transmitting coil 112 has a hollow region containing no conductor at a position including the central axis CX. The central axis CX is the central axis CX of the coil unit 10, and extends in the up-down direction, passing through the centers of the aluminum plate 12, the ferrite plate 13, and the power transmitting coil 112. In this embodiment, the direction in which the central axis CX extends is parallel to the stacking direction. That is, the power transmitting coil 112 in this embodiment is formed by being wound in a direction intersecting the stacking direction.

[0025] When an AC current flows through the power transmitting coil 112, a magnetic flux is formed around the power transmitting coil 112. The magnetic flux formed around the power transmitting coil 112 passes through the hollow region of the power transmitting coil 112, the ferrite plate 13, and the outer periphery of the power transmitting coil 112. When part of the magnetic flux formed around the power transmitting coil 112 interlinks with the power receiving coil 212, an AC current flows through the power receiving coil 212. When an AC current flows through the power receiving coil 212, a magnetic flux is also formed around the power receiving coil 212. The magnetic flux interlinking both the power transmitting coil 112 and the power receiving coil 212 allows the power receiving coil 212 to receive power from the power transmitting coil 112 in a wireless manner.

[0026] For ease of understanding, Fig. 4 does not illustrate the cover 11, but illustrates the components inside the cover 11 as viewed from the cover 11 side. A partition plate 31 is provided inside the cover 11. As shown in Fig. 4, the partition plate 31 has an annular shape with a rectangular outer edge in a plan view, and is disposed in a hollow region of the power transmission coil 112, which is indicated by hatching. Also, as shown in Fig. 5, in this embodiment, the partition plate 31 extends from the lower surface of the cover 11 along the stacking direction and is formed integrally with the cover 11. Note that the partition plate 31 may be formed as a separate member from the cover 11.

[0027] As shown in Fig. 5, the ferrite plate 13 of this embodiment has a through-hole 41. The end of the partition plate 31 is inserted into the through-hole 41 and abuts against the aluminum plate 12 when the cover 11 and the aluminum plate 12 are fitted together. As a result, when an external force is applied to the cover 11, the external force is supported by the aluminum plate 12 via the partition plate 31, thereby preventing the cover 11 from being deformed by the external force. Furthermore, the end of the partition plate 31 in the stacking direction is inserted into the through-hole 41 and does not abut against the ferrite plate 13, preventing the external force applied to the cover 11 from being applied to the ferrite plate 13 and preventing the ferrite plate 13 from being deformed by the external force.

[0028] The partition plate 31 defines a sealed space when the cover 11 and the aluminum plate 12 are fitted together. In other words, the partition plate 31 divides the sealed space formed between the cover 11 and the aluminum plate 12 into a sealed space outside the partition plate 31 and a sealed space inside the partition plate 31. In this embodiment, a fluid substance is sealed in each of the multiple sealed spaces separated by the partition plate 31. In this embodiment, oil is sealed as the fluid substance. When an external force is applied to the cover 11 and the cover 11 is deformed, the volume of the sealed space is reduced, the pressure of the fluid substance increases, and a force that resists the reduction in the volume of the sealed space acts from inside the cover 11. This prevents deformation of the cover 11 due to external force. Furthermore, because the fluid substance has fluidity, the fluid substance can disperse an external force applied to the cover 11, thereby preventing localized external force from acting on the cover 11.

[0029] The coil unit 10 of the first embodiment described above includes a fluid material sealed in a sealed space, so when an external force is applied to the cover 11 and the cover 11 is deformed, the volume of the sealed space is reduced, the pressure of the fluid material increases, and a force that resists the reduction in the volume of the sealed space acts from inside the cover 11. Therefore, it is possible to suppress deformation of the cover 11 due to the external force while suppressing deformation due to localized application of the external force to the equipment housed in the sealed space.

[0030] Furthermore, since the cover 11 is provided with the partition plate 31, the pressure of the fluid material that increases when an external force is applied to the cover 11 can be absorbed by the partition plate 31, thereby preventing localized pressure from being applied to the outer edge of the cover 11.

[0031] Furthermore, the ferrite plate 13 has a through-hole 41, and the partition plate 31 is inserted into the through-hole 41 and does not abut against the ferrite plate 13, so that an external force applied to the cover 11 is prevented from being applied to the ferrite plate 13, and deformation of the ferrite plate 13 due to the external force can be prevented. In addition, since the end of the partition plate 31 is inserted into the through-hole 41 and abuts against the aluminum plate 12, when an external force is applied to the cover 11, the external force can be supported by the aluminum plate 12 via the partition plate 31, and deformation of the cover 11 can be prevented.

[0032] B. Second Embodiment: As shown in Figures 6, 7 and 8, a coil unit 10A of the second embodiment differs from the coil unit 10 of the first embodiment in that it includes a first power transmitting resonant circuit 110a and a second power transmitting resonant circuit 110b instead of the power transmitting resonant circuit 110, a ferrite plate 13A instead of the ferrite plate 13, and partition plates 31a and 31b instead of the partition plate 31. The device configuration of the coil unit 10A of the second embodiment is the same as that of the coil unit 10 of the first embodiment, and therefore the same components are denoted by the same reference numerals and detailed description thereof will be omitted.

[0033] The circuit configurations of the first power transmitting resonant circuit 110a and the second power transmitting resonant circuit 110b will be described with reference to Fig. 6. The first power transmitting resonant circuit 110a has a first power transmitting coil 112a and a first power transmitting side capacitor 116a connected in series to each other. The second power transmitting resonant circuit 110b has a second power transmitting coil 112b and a second power transmitting side capacitor 116b connected in series to each other. Here, the first power transmitting coil 112a corresponds to the "first coil" in this disclosure. The first power transmitting side capacitor 116a corresponds to the "first capacitor" in this disclosure. The second power transmitting coil 112b corresponds to the "second coil" in this disclosure. The second power transmitting side capacitor 116b corresponds to the "second capacitor" in this disclosure.

[0034] The first power transmitting coil 112a of the first power transmitting resonant circuit 110a and the second power transmitting coil 112b of the second power transmitting resonant circuit 110b are not electrically connected to each other. The first power transmitting coil 112a and the first power transmitting side capacitor 116a, and the second power transmitting coil 112b and the second power transmitting side capacitor 116b are configured so that the resonant frequency of the first power transmitting resonant circuit 110a and the resonant frequency of the second power transmitting resonant circuit 110b match each other. By matching the resonant frequency of the first power transmitting resonant circuit 110a and the resonant frequency of the second power transmitting resonant circuit 110b, it is possible to suppress the reactive power component of the AC power in the first power transmitting coils 112a and 112b, and to suppress a decrease in power supply efficiency in the contactless power transfer system 300.

[0035] The configuration of the coil unit 10A of this embodiment will be described with reference to Figures 7 and 8. As shown in Figure 7, the first power transmission coil 112a and the second power transmission coil 112b are concentrically arranged on the ferrite plate 13A and are not electrically connected to each other. In this disclosure, the term "concentrically arranged" does not require that the central axis CX of the first power transmission coil 112a and the central axis CX of the second power transmission coil 112b strictly coincide with each other. Furthermore, the planar shape of the outer edge of each coil is not limited to a circle and may be any annular shape.

[0036] 8, the ferrite plate 13A has a through portion 41a and a through portion 41b. The through portion 41a is provided to correspond to a space formed in a radial gap between the first power transmitting coil 112a and the second power transmitting coil 112b, and the through portion 41b is provided to be located radially inward of the second power transmitting coil 112b.

[0037] 8 , the partition plates 31a and 31b extend from the lower surface of the cover 11A in the stacking direction and are formed integrally with the cover 11A. Note that at least one of the partition plates 31a and 31b may be formed as a separate member from the cover 11A. When the cover 11A and the aluminum plate 12 are fitted together, the end of the partition plate 31b is inserted into the through-hole 41b and abuts against the aluminum plate 12. When the cover 11A and the aluminum plate 12 are fitted together, the end of the partition plate 31a is inserted into the radial gap between the first power feeding coil 112a and the second power feeding coil 112b and the through-hole 41a and abuts against the aluminum plate 12. Therefore, when an external force is applied to the cover 11, the external force is supported by the aluminum plate 12 via the partition plates 31a and 31b, which can further prevent the cover 11 from being deformed by the external force compared to, for example, a configuration in which the cover 11 is supported by the aluminum plate 12 only via the partition plate 31a. Furthermore, the tip of the partition plate 31a is inserted through the radial gap between the first power feeding coil 112a and the second power feeding coil 112b and the through-hole 41a, and does not come into contact with the first power feeding coil 112a, the second power feeding coil 112b, or the ferrite plate 13. This can prevent the external force applied to the cover 11A from being applied to each member, and can prevent each member from being deformed by the external force.

[0038] The coil unit 10A of the second embodiment described above provides the same effects as those of the first embodiment. Furthermore, when the cover 11 and the aluminum plate 12 are fitted together, the end of the partition plate 31a is inserted through the radial gap between the first power transmission coil 112a and the second power transmission coil 112b and the through-hole 41a and comes into contact with the aluminum plate 12. Therefore, an external force can be supported by the aluminum plate 12 via the partition plate 31a at a portion of the cover 11A that corresponds to the radial gap between the first power transmission coil 112a and the second power transmission coil 112b, further preventing the cover 11A from being deformed by the external force.

[0039] Furthermore, since the resonant frequency of the first power transmission resonant circuit 110a and the resonant frequency of the second power transmission resonant circuit 110b are the same, the reactive power component of the AC power in the first power transmission coils 112a and 112b can be suppressed, and a decrease in power supply efficiency in the contactless power supply system 300 can be suppressed.

[0040] C. Third Embodiment: As shown in Figures 9 and 10, the coil unit 10B of the third embodiment differs from the coil unit 10A of the second embodiment in that it includes a ferrite plate 13B instead of the ferrite plate 13A. Since the device configuration of the coil unit 10B of the third embodiment is the same as that of the coil unit 10A of the second embodiment, the same components are denoted by the same reference numerals and detailed description thereof will be omitted. Note that Figure 10 shows an enlarged view of the area AR enclosed by the dashed line in Figure 9.

[0041] 9 and 10 , the ferrite plate 13B has a protrusion 51 that protrudes along the partition plate 31a inserted through the through-hole 41a on the surface on which the first power transmission coil 112a and the second power transmission coil 112b are placed. Compared to a configuration without the through-hole 41a, the configuration with the through-hole 41a increases magnetic resistance due to the interruption of the magnetic material at the through-hole 41a, reducing the power supply efficiency of the contactless power supply system 300. Therefore, in this embodiment, the protrusion 51 increases the area of ​​the portions of the ferrite plate 13B that face each other across the partition plate 31a in the direction perpendicular to the stacking direction. This reduces the reduction in magnetic flux at the portions where the magnetic material is interrupted by the through-hole 41a, thereby reducing the increase in magnetic resistance. This reduces the reduction in power supply efficiency of the contactless power supply system 300. Additionally, in this embodiment, when the partition plate 31a is inserted into the through-hole 41a, the protrusion 51 and the partition plate 31b are in contact with each other, which reduces the distance between the opposing portions of the ferrite plate 13B across the partition plate 31a in the direction perpendicular to the stacking direction, thereby suppressing an increase in magnetic resistance.

[0042] 10 , in this embodiment, the dimension of the protrusion 51 along the stacking direction is larger than the dimensions of the first power transmission coil 112a and the second power transmission coil 112b along the stacking direction. This makes it easier for magnetic flux generated by a current flowing through the first power transmission coil 112a to be induced in the magnetic protrusion 51, and the magnetic flux passes through the second power transmission coil 112b, thereby suppressing eddy current loss generated in the second power transmission coil 112b. This makes it possible to suppress a decrease in power transmission efficiency in the contactless power transfer system 300.

[0043] The coil unit 10 of the third embodiment described above provides the same effects as those of the second embodiment. In addition, since the protrusion 51 is provided, the area of ​​the portions of the ferrite plates 13B that face each other across the partition plate 31a in the direction perpendicular to the stacking direction can be increased, and the reduction in magnetic flux in the portions where the magnetic material is interrupted by the through-holes 41a can be suppressed, thereby suppressing an increase in magnetic resistance. Therefore, a decrease in power supply efficiency in the contactless power supply system 300 can be suppressed.

[0044] D. Fourth Embodiment: As shown in Fig. 11, a coil unit 10C of the fourth embodiment differs from the coil unit 10A of the second embodiment in that it includes a cover 11C instead of the cover 11A, and a ferrite plate 13C instead of the ferrite plate 13A. The device configuration of the coil unit 10C of the fourth embodiment is the same as that of the coil unit 10A of the second embodiment, and therefore the same components are denoted by the same reference numerals and detailed description thereof will be omitted.

[0045] The ferrite plate 13C is formed as a plate-like member without a through-hole. With this type of ferrite plate 13C, there are no interruptions in the magnetic material, so an increase in magnetic resistance can be suppressed compared to a type with a through-hole.

[0046] The cover 11C includes partition plates 31c and 31d instead of the partition plates 31a and 31b included in the cover 11A of the second embodiment. The partition plates 31c and 31d extend from the underside of the cover 11C along the stacking direction and are integrally formed with the cover 11C. In this embodiment, the ends of the partition plates 31c and 31d are spaced apart from the ferrite plates 13C along the stacking direction. Therefore, even if an external force is applied to the cover 11C, the external force is prevented from being transmitted to the ferrite plates 13C, thereby preventing deformation of the ferrite plates 13C. Furthermore, because the cover 11C includes the partition plates 31c and 31d, the pressure of the fluid material that increases when an external force is applied to the cover 11C can be absorbed by the partition plates 31c and 31d, preventing localized pressure from being applied to the outer edge of the cover 11C. Furthermore, since the flow path can be narrowed between the tip ends of the partition plates 31c and 31d and the ferrite plate 13, the flow of the fluid material between the regions partitioned by the partition plates can be suppressed.

[0047] The coil unit 10C of the fourth embodiment described above includes a fluid material sealed in a sealed space, so when an external force is applied to the cover 11C and the cover 11C is deformed, the volume of the sealed space contracts, the pressure of the fluid material increases, and a force acts from inside the cover 11C that resists the contraction of the volume of the sealed space. This makes it possible to suppress deformation of the cover 11C due to external forces.

[0048] Furthermore, because partition plates 31c and 31d are provided, the pressure of the fluid material that increases when an external force is applied to cover 11C can be received by partition plates 31c and 31d, thereby preventing pressure from being applied locally to the outer edge of cover 11C. In addition, the flow path can be narrowed between the tips of partition plates 31c and 31d and ferrite plate 13, preventing the flow of the fluid material between the regions separated by the partition plates.

[0049] Furthermore, the ends of the partition plates 31c and 31d are spaced apart from the ferrite plates 13C in the stacking direction, so that even if an external force is applied to the cover 11C, the external force can be prevented from being transmitted to the ferrite plates 13C, and deformation of the ferrite plates 13C can be prevented.

[0050] E. Fifth Embodiment: As shown in Fig. 12, a coil unit 10D of the fifth embodiment differs from the coil unit 10 of the first embodiment in that a cover 11D is provided instead of the cover 11. The device configuration of the coil unit 10D of the fifth embodiment is the same as that of the coil unit 10 of the first embodiment, and therefore the same components are denoted by the same reference numerals and detailed description thereof will be omitted.

[0051] During the manufacture of coil unit 10D, cover 11D has filling opening 61 and discharge opening 71, as well as filling opening 63 and discharge opening 73. Filling opening 61 and discharge opening 71 are formed to correspond to the sealed space formed outside partition plate 31, and filling opening 63 and discharge opening 73 are formed to correspond to the sealed space formed inside partition plate 31. In this way, when the sealed space is divided into multiple spaces by partition plates, a pair of filling openings and discharge openings is provided for each sealed space. Filling opening 61 and discharge opening 71, as well as filling opening 63 and discharge opening 73, are sealed after the filling of the fluid material is completed.

[0052] The filling port 61 and the filling port 63 communicate between the outside of the cover 11D and the sealed space and are used to fill the sealed space with the fluid material. The discharge port 71 and the discharge port 73 communicate between the outside of the cover 11D and the sealed space and are used to discharge the air present in the sealed space when the fluid material is filled.

[0053] The inner surface of cover 11D is inclined so that the dimension along the stacking direction of the sealed space formed when cover 11D and aluminum plate 12 are fitted together increases from filling inlet 61 toward discharge outlet 71 and from filling inlet 63 toward discharge outlet 73. This makes it easier for air present in the sealed space to be guided to discharge outlet 71, which is located above filling inlet 61, and discharge outlet 73, which is located above filling inlet 63, when the fluid material is filled into the sealed space with cover 11D positioned above aluminum plate 12, thereby preventing air from remaining in the sealed space.

[0054] The coil unit 10D of the fifth embodiment described above achieves the same effects as the first embodiment. In addition, the coil unit 10D further includes an inlet 61 and an outlet 71, and an inlet 63 and an outlet 73. The inner surface of the cover 11D is inclined such that the dimension along the stacking direction of the sealed space formed when the cover 11D and the aluminum plate 12 are fitted together increases from the inlet 61 toward the outlet 71 and from the inlet 63 toward the outlet 73. This makes it easier for air present in the sealed space to be guided to the outlets 71 and 73 when the sealed section is filled with a fluid material with the cover 11D positioned above the aluminum plate 12, thereby preventing air from remaining in the sealed space.

[0055] F. Other Embodiments: (F1) In the above embodiment, the cover 11, the aluminum plate 12, and the ferrite plate 13 have a rectangular external shape in a plan view, but the present disclosure is not limited to this. The cover 11, the aluminum plate 12, and the ferrite plate 13 may have any external shape, such as a trapezoid or a circle in a plan view. The power transmitting coil 112 may be wound to have any shape corresponding to the shapes of the cover 11, the aluminum plate 12, and the ferrite plate 13. Furthermore, the partition plate 31 may have any shape corresponding to the shape of the hollow region formed by the winding of the power transmitting coil 112. A coil unit 10 of this configuration also achieves the same effects as the above embodiment.

[0056] (F2) In the above embodiment, the power transmitting coil 112 is wound in a direction intersecting the stacking direction so that the central axis CX is parallel to the stacking direction, but the present disclosure is not limited to this. The power transmitting coil 112 may be wound so that the central axis CX intersects the stacking direction. This configuration also achieves the same effects as the above embodiment.

[0057] (F3) In the above embodiment, the power transmission coil 112 is formed by winding a conductor such as a magnet wire around the central axis CX, but the present disclosure is not limited to this. The power transmission coil 112 may be formed by a conductive pattern formed on a printed wiring board. A coil unit 10 of this type also achieves the same effects as the above embodiment.

[0058] (F4) In the above embodiment, oil is sealed in the sealed space as the fluid substance, but the present disclosure is not limited to this. The fluid substance may be any substance having fluidity, such as gas, liquid, powder, or gel. Here, a fluid substance having a density higher than air at standard conditions is preferable because it has a greater resistance to volume compression than a substance having a density lower than air at standard conditions. Note that a fluid substance in which powder is mixed with a liquid may also be used.

[0059] It is preferable that the fluid material has a higher viscosity than water, since this increases the resistance when an external force is applied and the fluid material flows in the enclosed space. In this embodiment, most of the external forces applied to the coil unit 10 are loads that are momentarily applied when, for example, a vehicle 200 runs over and passes over the power transmission coil 112. Therefore, the fluid material is not limited to a material that has a constantly high viscosity, and a material whose viscosity temporarily increases when an external force is momentarily applied, more specifically, a dilatant fluid, may also be used.

[0060] Furthermore, the lower the thermal resistance of the fluid material, the more easily it can dissipate heat generated in the power transmission coil 112. Furthermore, the higher the electrical insulation of the fluid material, the more it can suppress leakage of electricity from the power transmission coil 112 and suppress a decrease in power supply efficiency in the contactless power transfer system 300. Furthermore, the fluid material can increase the resistance to deformation of the cover 11 by applying a higher pressure when filling the sealed space. Furthermore, the higher the viscosity of the fluid material, the more it can suppress leakage of the fluid material from the sealed space and suppress a decrease in the resistance to volumetric reduction of the sealed space due to leakage of the fluid material.

[0061] (F5) In the above embodiment, the coil unit 10 is provided in the power transmitter 100, but the present disclosure is not limited to this. The coil unit 10 may be provided in the vehicle 200.

[0062] (F6) In the second embodiment, the first power transmitting coil 112a and the first power transmitting side capacitor 116a, and the second power transmitting coil 112b and the second power transmitting side capacitor 116b are connected in series, but the present disclosure is not limited to this. The first power transmitting coil 112a and the first power transmitting side capacitor 116a may be connected in parallel, and the second power transmitting coil 112b and the second power transmitting side capacitor 116b may be connected in parallel. This configuration also achieves the same effects as the above embodiment.

[0063] (F7) In the third embodiment, when the partition plate 31a is inserted into the through-hole 41a, the protrusion 51 and the partition plate 31b are in contact with each other. However, the present disclosure is not limited to this. A gap may exist between the protrusion 51 and the partition plate 31b. This configuration of the coil unit 10C also achieves the same effects as the third embodiment. In addition, the gap between the protrusion 51 and the partition plate 31b makes it easy to insert the partition plate 31b into the protrusion 51 and the through-hole 41a.

[0064] (F8) In the fourth embodiment, the coil unit 10C includes the first power transmission coil 112a and the second power transmission coil 112b, but the present disclosure is not limited to this. The coil unit 10C may include the power transmission coil 112 as in the first embodiment, and the partition plate 31c may be formed so that its end is spaced apart from the power transmission coil 112 along the stacking direction. This configuration also prevents external forces applied to the cover 11C from being transmitted to the power transmission coil 112 and causing deformation of the power transmission coil 112. In addition, there is no need to separate the coil to prevent contact between the partition plate 31c and the coil, which prevents the configuration of the coil unit from becoming complicated.

[0065] Furthermore, either the partition plate 31c or the partition plate 31d may abut against the power transmitting coil 112 or the ferrite plate 13B. This configuration also makes it possible to prevent the power transmitting coil 112 or the ferrite plate 13B from being deformed by an external force, compared to a configuration in which both the partition plate 31c and the partition plate 31d abut against the power transmitting coil 112 or the ferrite plate 13B.

[0066] (F9) In the above embodiment, the coil unit 10 includes the partition plate 31, but the present disclosure is not limited to this. The coil unit 10 does not need to include the partition plate 31. Even in this embodiment, the coil unit 10 includes a fluid material sealed in a sealed space. Therefore, when an external force is applied to the cover 11 and the cover 11 is deformed, the volume of the sealed space is reduced, the pressure of the fluid material increases, and a force that resists the reduction in the volume of the sealed space acts from inside the cover 11. Therefore, deformation of the cover 11 due to the external force can be suppressed while suppressing deformation due to localized external force acting on the equipment housed in the sealed space.

[0067] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in each embodiment corresponding to the technical features in the form described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. (Mode 1) A coil unit (10, 10A, 10B, 10C, 10D) for use in a contactless power supply system (300), comprising: a substrate (12), a cover (11, 11A, 11C, 11D) forming an enclosed space between the substrate and the cover, a magnetic plate (13, 13A, 13B, 13C) placed on the substrate within the enclosed space, a coil (112, 212) for transmitting or receiving AC power, the coil being placed on the magnetic plate in a stacking direction within the enclosed space, and a fluid material having fluidity and sealed in the enclosed space. (Mode 2) The coil unit according to Mode 1, wherein the fluid material is a material having a density greater than that of air at standard conditions. (Mode 3) The coil unit according to Mode 1 or Mode 2, further comprising a partition plate (31, 31a, 31b, 31c, 31d) extending along the stacking direction within the sealed space. (Mode 4) The coil unit according to Mode 3, wherein the magnetic plate has a through portion (41, 41a, 41b) through which the partition plate is inserted, and an end of the partition plate is inserted into the through portion and abuts against the substrate, dividing the sealed space.(Mode 5) The coil unit according to Mode 4, wherein the coil has a first coil (112a) and a second coil (112b) that are concentrically arranged and are not electrically connected to each other, the through-holes (41a, 41b) are provided to correspond to a space formed in a radial gap between the first coil and the second coil, and the partition plates (31a, 31b) are inserted into the through-holes via the radial gap between the first coil and the second coil and abut against the substrate. (Mode 6) The coil unit according to Mode 5, comprising: a first power transmitting resonant circuit (110a) having the first coil and a first capacitor (116a), and a second power transmitting resonant circuit (116b) having the second coil and a second capacitor (116b), wherein a resonant frequency of the first power transmitting resonant circuit and a resonant frequency of the second power transmitting resonant circuit match each other. (Mode 7) The coil unit according to any one of Modes 4 to 6, wherein the magnetic plate has a protrusion (51) that protrudes along the partition plate inserted into the through-hole on the surface on which the coil is placed. (Mode 8) The coil unit according to Mode 3, wherein an end of the partition plate (31c, 31d) is spaced apart from at least one of the magnetic plate and the coil along the stacking direction. (Form 9) A coil unit described in any one of Forms 1 to 8, wherein the cover (11D) further comprises: an inlet (61, 63) communicating the outside of the cover with the sealed space, the inlet being for sealing the fluid material into the sealed space; and an outlet (71, 73) communicating the outside of the cover with the sealed space, the outlet being for releasing air present in the sealed space when the fluid material is sealed in the sealed space; and the inner surface side of the cover has a slope such that the dimension along the stacking direction of the sealed space increases from the inlet toward the outlet.

Claims

1. A coil unit (10, 10A, 10B, 10C, 10D) for use in a contactless power supply system (300), comprising: a substrate (12); a cover (11, 11A, 11C, 11D) forming an enclosed space between the substrate and the coil; a magnetic plate (13, 13A, 13B, 13C) placed on the substrate within the enclosed space; a coil (112, 212) for transmitting or receiving AC power, the coil being placed on the magnetic plate in a stacking direction within the enclosed space; and a fluid material having fluidity that is sealed in the enclosed space.

2. A coil unit according to claim 1, wherein the fluid material is a material having a density greater than that of air under standard conditions.

3. A coil unit as claimed in claim 1, further comprising a partition plate (31, 31a, 31b, 31c, 31d) extending along the stacking direction within the sealed space.

4. A coil unit as claimed in claim 3, wherein the magnetic plate has a through-portion (41, 41a, 41b) through which the partition plate is inserted, and an end of the partition plate is inserted into the through-portion and abuts against the substrate, dividing the sealed space.

5. A coil unit as described in claim 4, wherein the coil has a first coil (112a) and a second coil (112b) that are concentrically arranged and are not electrically connected to each other, the through-holes (41a, 41b) are provided to correspond to a space formed in a radial gap between the first coil and the second coil, and the partition plates (31a, 31b) are inserted into the through-holes via the radial gap between the first coil and the second coil and abut against the substrate.

6. A coil unit according to claim 5, comprising: a first power transmitting resonant circuit (110a) having the first coil and a first capacitor (116a); and a second power transmitting resonant circuit (116b) having the second coil and a second capacitor (116b), wherein the resonant frequency of the first power transmitting resonant circuit and the resonant frequency of the second power transmitting resonant circuit are mutually identical.

7. A coil unit as claimed in any one of claims 4 to 6, wherein the magnetic plate has a protrusion (51) on the surface on which the coil is placed that protrudes along the partition plate inserted into the through-hole.

8. A coil unit according to claim 3, wherein the ends of the partition plates (31c, 31d) are spaced apart from at least one of the magnetic plate and the coil along the stacking direction.

9. A coil unit as described in any one of claims 1 to 6 and claim 8, wherein the cover (11D) further comprises: an inlet (61, 63) communicating the outside of the cover with the sealed space, for sealing the fluid material in the sealed space; and an outlet (71, 73) communicating the outside of the cover with the sealed space, for releasing air present in the sealed space when the fluid material is sealed in the sealed space, and the inner surface side of the cover has a slope such that the dimension along the stacking direction of the sealed space increases from the inlet toward the outlet.

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