Coil unit

Abstract

The invention provides a coil unit capable of suppressing an increase in weight and improving cooling efficiency. A coil unit for a vehicle is provided with: a housing (11); a coil (13) that acquires AC power transmitted in a non-contact manner from the power transmission device (T); and a support member (31). The housing (11) has a surface (11A) exposed to the outside below the vehicle body. A coil (13) disposed inside the housing (11) is in direct contact with the housing (11) via a heat dissipation member (11b) provided on the inner surface (11B) of the housing (11). The support member (31) is in contact with the inner surface (11B) of the housing (11) and the heat dissipation member (11b), and covers the surface of the coil (13). The width of the support member (31) in the direction orthogonal to the direction in which the heat dissipation member (11b) protrudes changes in an increasing tendency from the tip side of the heat dissipation member (11b) toward the inner surface (11B) in the direction in which the heat dissipation member (11b) protrudes.

Description

Technical Field

[0001] The present invention relates to a coil unit. Background Art

[0002] In recent years, in order to ensure that more people can obtain sustainable and advanced energy that is suitable and reliable, research and development related to charging stations for vehicles equipped with secondary batteries that contribute to energy efficiency has been carried out.

[0003] In the past, the following device is known: in a non-contact power transmission system that supplies power to a vehicle from the outside of the vehicle through non-contact power transmission, mechanical strength and heat dissipation are ensured by covering each coil used for power transmission and power reception with a thermally conductive resin (for example, refer to Japanese Patent Gazette No. 2008-87733). Summary of the invention

[0004] In the technology related to the charging and power supply of a vehicle equipped with a secondary battery, it is desired to suppress the increase in weight while ensuring the cooling of the coil unit on the vehicle side. In the non-contact power supply device of the above-mentioned prior art, it is desired to reduce the thermal resistance generated by the housing to the coil and the heat-generating components without the need for a structure such as a cooling device that increases the weight, thereby improving the cooling efficiency.

[0005] An object of an aspect of the present invention is to provide a coil unit capable of improving cooling efficiency while suppressing an increase in weight. In addition, an aspect of the present invention further contributes to improving energy efficiency.

[0006] The coil unit involved in the first scheme of the present invention comprises: a shell having a surface exposed to the outside below a vehicle body; a heat dissipation component that protrudes inward from an inner surface of the shell on the inner side relative to the surface; a coil that is arranged inside the shell and obtains AC power transmitted from a power transmission device in a non-contact manner; and a supporting component that contacts the inner surface of the shell and the heat dissipation component and covers at least a portion of the surface of the coil, and the width of the supporting component in a direction orthogonal to the protruding direction of the heat dissipation component tends to increase along the protruding direction from the top end side of the heat dissipation component toward the inner surface.

[0007] According to a second aspect, in the coil unit according to the first aspect, the support member may be formed of a material having predetermined electrical insulation and thermal conductivity.

[0008] A third option, based on the coil unit described in the second option, may be that the thickness of the supporting member covering the top end surface of the coil in the protruding direction is set according to the electrical insulation, and the thickness of the supporting member covering the surface of the coil on the opposite side to the heat dissipation member in the orthogonal direction is set according to the thermal conductivity.

[0009] A fourth aspect is the coil unit according to any one of the first to third aspects, wherein the case includes the surface having a groove formed thereon, the groove being along a flow direction of wind received during traveling.

[0010] According to the first embodiment, the width of the support member increases as it moves from the top end of the heat dissipation member toward the inner surface of the housing along the protruding direction, thereby increasing the amount of heat transferred to the inner surface and improving the cooling efficiency. For example, compared with a case where the width of the support member is constant along the protruding direction, the weight and volume of the support member can be suppressed from increasing.

[0011] In the case of the second aspect, the desired withstand voltage and heat dissipation can be ensured by the support member having predetermined electrical insulation and thermal conductivity with respect to the heat-generating coil.

[0012] In the case of the third aspect, it is possible to ensure desired withstand voltage and heat dissipation properties while suppressing increases in weight and volume of the support member.

[0013] In the fourth aspect, the coil can be cooled from the surface of the housing by the grooves that efficiently guide the wind when the vehicle is running. The coil is in contact with the housing via the support member, thereby reducing thermal resistance and improving cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an exploded perspective view showing the structure of the coil unit in the embodiment of the present invention.

[0015] Figure 2 is Figure 1 The position of the AA line shown is a cross-sectional view obtained by cutting the coil unit in the embodiment of the present invention along the ZX plane.

[0016] Figure 3 This is a diagram showing an enlarged view of a coil and a case in a coil unit according to an embodiment of the present invention.

[0017] Figure 4 It is a diagram showing a process of integrating the coil and the case in the coil unit according to the embodiment of the present invention. DETAILED DESCRIPTION

[0018] Hereinafter, a coil unit according to an embodiment of the present invention will be described with reference to the drawings.

[0019] Figure 1 It is an exploded perspective view showing the structure of coil unit 10 in the embodiment. Figure 2 is Figure 1 The position of the AA line shown is a cross-sectional view obtained by cutting the coil unit 10 according to the embodiment along the ZX plane.

[0020] Hereinafter, the directions of the X-axis, Y-axis, and Z-axis that are orthogonal to each other in a three-dimensional space are directions parallel to the axes. Figure 1 and Figure 2 As shown, the Z-axis direction is parallel to the up-down direction of a moving body such as a vehicle carrying the coil unit 10, the X-axis direction is parallel to the front-rear direction of the moving body, and the Y-axis direction is parallel to the left-right direction of the moving body. For example, the positive direction of the Z-axis is the upward direction of the moving body, the positive direction of the X-axis is the front direction of the moving body, and the positive direction of the Y-axis is the right direction of the moving body.

[0021] The coil unit 10 of the embodiment is mounted on a vehicle that obtains power from the outside through contactless power transmission, for example. The vehicle is an electric vehicle such as an electric vehicle, a hybrid vehicle, and a fuel cell vehicle. The coil unit 10 is fixed to the lower part of a frame-shaped subframe provided at the lower part of the vehicle body, for example. The coil unit 10 constitutes a part of a power receiving device that obtains AC power from an external power transmission device T through contactless power transmission.

[0022] like Figure 1 and Figure 2 As shown, the coil unit 10 includes, for example, a case 11 , a first cover 12 , a coil 13 , an insulating member 14 , a core member 15 , a back member 16 , an inner member 17 , and a second cover 18 .

[0023] The outer shape of the housing 11 is formed into, for example, a rectangular frame shape. The housing 11 is formed of, for example, a material such as a resin having a predetermined thermal conductivity. The housing 11 includes, for example, a first housing portion 21 and a second housing portion 22. The coil 13, the insulating member 14, and the core member 15 described later are arranged in the first housing portion 21. The substrates 23, 26, 27, the capacitor 24, and the semiconductor element 28 described later are arranged in the second housing portion 22. The first housing portion 21 is, for example, provided to surround the lower side of the up-down direction and the inner and outer sides in the direction orthogonal to the up-down direction with respect to the coil 13, the insulating member 14, and the core member 15 described later. The second housing portion 22 is, for example, provided at a position further back than the first housing portion 21 in the front-rear direction. The second housing portion 22 is, for example, provided to surround the lower side of the up-down direction and the outer sides in the direction orthogonal to the up-down direction with respect to the substrates 23, 26, 27, the capacitor 24, and the semiconductor element 28 described later.

[0024] The housing 11 includes a surface 11A on which a plurality of grooves 11a are formed, for example. The surface 11A of the housing 11 (ie, the surface on the lower side in the up-down direction, ie, the lower surface) is exposed to the outside below the vehicle body.

[0025] The plurality of grooves 11 a are provided along the flow direction of wind (travel wind) received by the vehicle when it travels, for example, formed along the front-rear direction.

[0026] The housing 11 includes, for example, a plurality of heat dissipating members 11 b protruding from an inner surface 11B on the inner side relative to the surface 11A. The heat dissipating members 11 b have, for example, a plate-like fin shape. The plurality of heat dissipating members 11 b are in contact with the coil 13 .

[0027] The outer shape of the first cover 12 is, for example, a rectangular plate having a through hole 12a formed in the thickness direction. The first cover 12 is, for example, provided to surround the upper side in the up-down direction relative to the coil 13, the insulating member 14, and the core member 15 described later. The first cover 12 forms a housing space for housing the coil 13, the insulating member 14, and the core member 15 between the first cover 12 and the inner surface 11B of the housing 11. The first cover 12 blocks the open end of the first housing portion 21 of the housing 11 that houses the coil 13, the insulating member 14, and the core member 15.

[0028] The outer shape of the coil 13 is formed in, for example, a rectangular spiral shape along the inner surface 11B of the housing 11. The coil 13 is disposed, for example, on the upper side of the inner surface 11B. The wire of the coil 13 is in direct contact with the plurality of heat dissipating members 11b.

[0029] The insulating member 14 has a rectangular sheet shape with a through hole 14 a formed in the thickness direction. The insulating member 14 is made of a material having electrical insulation. The insulating member 14 is disposed, for example, above the coil 13 .

[0030] The outer shape of the core member 15 is, for example, a rectangular plate having a through hole 15a formed in the thickness direction. The core member 15 is, for example, formed of a magnetic material having a relatively large magnetic permeability, such as a non-directional (isotropic) magnetic material such as ferrite, an electromagnetic steel plate such as a silicon steel plate, or a directional (anisotropic) magnetic material such as a soft magnetic material such as a nanocrystalline soft magnetic material. The core member 15 is, for example, arranged on the upper side of the insulating member 14.

[0031] The outer shape of the back member 16 is formed, for example, in a rectangular plate shape with a through hole formed in the thickness direction. The outer shape of the inner member 17 is formed, for example, in a box shape having a rectangular frame-shaped wall portion and a cover portion that blocks the lower open end of the wall portion. The inner member 17 protrudes downward in the vertical direction from the peripheral portion surrounding the through hole of the back member 16. The back member 16 and the inner member 17 are integrally formed of a magnetic material having a relatively large magnetic permeability, such as an electromagnetic steel sheet such as a silicon steel sheet.

[0032] The back member 16 is disposed, for example, on the upper side in the up-down direction with respect to the first cover 12 .

[0033] The inner member 17 is inserted into the through holes 12a, 15a, 14a of the first cover 12, the core member 15, and the insulating member 14, the hollow region 13a of the coil 13, and the through hole 11c in the thickness direction of the case 11. The inner member 17 protrudes downward from the surface 11A of the case 11, for example.

[0034] The outer shape of the second cover 18 is formed into a hip roof type, for example. The second cover 18 forms a storage space for storing the substrates 23, 26, 27, the capacitor 24, and the semiconductor element 28 between the second cover 18 and the inner surface 11B of the housing 11. The second cover 18 blocks the open end of the second storage portion 22 of the housing 11 that stores the substrates 23, 26, 27, the capacitor 24, and the semiconductor element 28.

[0035] Capacitor substrate 23 fixes a plurality of capacitors 24 such as film capacitors. Capacitor 24 is, for example, a resonance capacitor connected to coil 13. Capacitors 24 are fixed to capacitor substrate 23 and contact inner surface 11B of housing 11 via heat conductive material 25 such as thermal compound.

[0036] The control substrate 26 is, for example, arranged above the capacitor substrate 23. The control substrate 26 controls, for example, power conversion of the power receiving device and communication with the external power transmitting device T. The control substrate 26 is a software function unit that performs functions by executing a predetermined program by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU (Electronic Control Unit), which has a processor such as a CPU, a ROM (Read Only Memory) for storing programs, a RAM (Random Access Memory) for temporarily storing data, and electronic circuits such as a timer. It should be noted that at least a part of the control substrate 26 may also be an integrated circuit such as an LSI (Large Scale Integration).

[0037] The control substrate 26 generates a control signal input to the gate drive substrate 27 according to the target output of the power receiving device, for example. The control signal is, for example, a signal indicating the timing of driving a plurality of switching elements constituting the power conversion unit of the power receiving device to be turned on (conducted) / off (cut off). For example, the control signal is a pulse width modulated signal, etc.

[0038] The gate drive substrate 27 is, for example, disposed above the control substrate 26. The gate drive substrate 27 is, for example, connected to gates of a plurality of switching elements constituting a power conversion unit of the power receiving device. The gate drive substrate 27 includes, for example, an integrated circuit, a plurality of gate resistors, and the like.

[0039] The gate drive substrate 27 generates a gate signal for actually driving each switching element to be turned on (conducting) or off (cutting off) based on the control signal received from the control substrate 26 .

[0040] For example, the gate driving substrate 27 performs amplification and level shifting of a control signal to generate a gate signal.

[0041] The semiconductor element 28 is, for example, a switching element and a rectifying element constituting the power conversion unit of the power receiving device. The switching element is, for example, a transistor such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) of SiC (Silicon Carbide). The rectifying element is, for example, a freewheeling diode connected in parallel with each transistor. The plurality of semiconductor elements 28 are, for example, fixed to the upper portion of the gate drive substrate 27 and arranged between the gate drive substrate 27 and the inner surface 18A of the second cover 18.

[0042] The second cover 18 includes a heat sink 29 disposed on an outer surface (surface) 18B on the opposite side to the inner surface 18A. The heat sink 29 is, for example, a cooling device including a plurality of fin members protruding to the outside.

[0043] In the coil unit 10 , the coil 13 , the insulating member 14 , and the core member 15 are sequentially stacked in the up-down direction and arranged in the first housing portion 21 of the case 11 .

[0044] Figure 3 This is a diagram showing an enlarged view of the coil 13 and the case 11 in the coil unit 10 according to the embodiment.

[0045] like Figure 3 As shown, the coil 13 is fixed to the heat dissipation member 11b of the housing 11 via the support member 31, for example. The support member 31 is formed of a material such as a resin having a specified electrical insulation and thermal conductivity. The specified material is, for example, polyarylate (PAR), polyphenylene sulfide (PPS) and polyurethane (PU). The insulation breakdown voltage of the specified material is, for example, about 10 to 20 kV / mm. The thermal conductivity of the specified material is, for example, about 0.2 to 4 W / mK. The support member 31 is formed of a material such as a thermosetting resin by a process such as so-called casting or injection molding such as vacuum injection molding.

[0046] Figure 4The diagram shows a step (casting step) of integrating the coil 13 and the case 11 in the coil unit 10 according to the embodiment.

[0047] like Figure 4 As shown, first, the spiral coil 13 is inserted between the plurality of heat dissipating members 11b inside the housing 11 and is arranged to be separated from the inner surface 11B and the heat dissipating members 11b by a predetermined distance (step S01).

[0048] Next, the plurality of cores 32 are inserted between the plurality of heat dissipating members 11b and arranged to be separated from the coil 13 by a predetermined distance (step S02). The shape of each core 32 is formed according to the shape of the supporting member 31 described later.

[0049] Next, a material such as a thermosetting resin is injected into a space around the coil 13 formed by the inner surface 11B of the case 11 , the heat dissipating members 11 b , and the cores 32 by so-called potting (step S03 ).

[0050] Next, after the material such as the thermosetting resin injected into the space around the coil 13 is cured to form the support member 31 , each core 32 is removed from the inside of the case 11 (step S04 ).

[0051] like Figure 3 As shown, the outer shape of the support member 31 covering the coil 13 is, for example, the following shape: along the direction (Z-axis direction) in which each heat dissipation member 11b protrudes from the inner surface 11B of the shell 11 (protruding direction), the thickness of the support member 31 in the direction orthogonal to the protruding direction tends to increase from the top side of each heat dissipation member 11b toward the inner surface 11B.

[0052] The outer shape of the support member 31 is, for example, a shape defined by a first thickness Wa and a second thickness Wb. The first thickness Wa is set, for example, based on the electrical insulation of the support member 31, and is a thickness (for example, several mm) required to ensure a predetermined electrical insulation (for example, a dielectric withstand voltage of several tens of kV, etc.). The second thickness Wb is set, for example, based on the thermal conductivity of the support member 31, and is a thickness required to ensure a predetermined thermal conductivity (for example, a heat transfer, etc.).

[0053] The first thickness Wa is, for example, the thickness of the portion covering the top end surface 13A of the coil 13 at the top end side of the heat dissipation member 11b in the direction along the protruding direction (Z-axis direction). The second thickness Wb is, for example, the thickness of the portion from the surface (end surface 13B) of the coil 13 on the side opposite to the heat dissipation member 11b side to the end of the support member 31 in the direction orthogonal to the protruding direction (for example, the X-axis direction) in the portion in contact with the inner surface 11B of the housing 11, that is, the thickness of the portion covering the end surface 13B of the coil 13.

[0054] In the support member 31 , each thickness of a portion between the coil 13 and the heat dissipation member 11 b and a portion between the coil 13 and the inner surface 11B is a constant thickness such as the first thickness Wa.

[0055] In the supporting member 31, the thickness of the portion covering the end face 13B of the coil 13 in the orthogonal direction tends to increase from a first thickness Wa to a second thickness Wb, for example, from the top end side of the heat dissipation member 11b toward the inner surface 11B in the direction along the protruding direction (Z-axis direction).

[0056] As described above, according to the coil unit 10 of the embodiment, the width of the supporting member 31 in the direction orthogonal to the protruding direction tends to increase along the protruding direction from the top end side of the heat dissipation member 11b toward the inner surface 11B of the shell 11, thereby increasing the heat transfer on the inner surface 11B side and improving the cooling efficiency.

[0057] Since the second thickness Wb is set on the inner surface 11B side where the heat transfer is relatively large, compared with the case where a constant thickness such as the second thickness Wb is set in the range of the protruding direction, it is possible to suppress an increase in weight and volume of the support member 31 while ensuring desired thermal conductivity.

[0058] The support member 31 having predetermined electrical insulation and thermal conductivity with respect to the coil 13 generating heat can ensure desired withstand voltage and heat dissipation.

[0059] It is possible to ensure desired withstand voltage and heat dissipation properties while suppressing an increase in the weight and volume of the support member 31 .

[0060] The grooves 11a efficiently guide the wind when the vehicle is running, so that the coil 13 can be cooled from the surface 11A of the case 11. The coil 13 is in contact with the case 11 via the support member 31, so that the thermal resistance can be reduced and the cooling efficiency can be improved.

[0061] (Variation Example)

[0062] It should be noted that in the above embodiment, the support member 31 is formed by vacuum injection molding using thermosetting resin as a material, but the present invention is not limited thereto. The support member 31 may be formed by other processes such as injection molding and other materials other than thermosetting resin.

[0063] The embodiments of the present invention are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are included in the invention and its equivalent scope as they are included in the scope and purpose of the invention.

Claims

1. A coil unit, wherein: The coil unit comprises: a housing having a surface exposed to the outside below the vehicle body; a heat dissipation member protruding inward from an inner surface of the housing on the inner side relative to the surface; a coil disposed inside the housing and receiving AC power transmitted from the power transmission device in a contactless manner; as well as a supporting member that contacts the inner surface of the housing and the heat dissipating member and covers at least a portion of the surface of the coil, The width of the support member in a direction orthogonal to the protruding direction of the heat dissipation member changes in a tendency to increase as it goes from the leading end side of the heat dissipation member toward the inner surface along the protruding direction.

2. The coil unit according to claim 1, wherein: The supporting member is formed of a material having predetermined electrical insulation and thermal conductivity.

3. The coil unit according to claim 2, wherein: The thickness of the support member covering the distal end surface of the coil in the protruding direction is set according to the electrical insulation. The thickness of the support member covering the surface of the coil on the side opposite to the heat dissipation member in the orthogonal direction is set according to the thermal conductivity.

4. The coil unit according to any one of claims 1 to 3, wherein: The housing includes the surface having grooves formed thereon, the grooves being along the flow direction of wind received during traveling.

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