Power transmission coil unit

Abstract

To provide a power-transmission coil unit having suppressed parasitic inductance.SOLUTION: A power-transmission coil unit 1 comprises a power transmission coil 2, and a power supply member 3 for supplying power from a power source to the power transmission coil 2, the power supply member being electrically connected to each of the power source and the power transmission coil 2. The power supply member 3 has a first metal plate 31 and a second metal plate 32 which are insulated to one another via an isolation layer 34. When power is supplied from the power source, a current flows to the power transmission coil 2 via one of the first metal plate 31 and the second metal plate 32, and the current having passed through the transmission coil 2 returns to the power source via the other of the first metal plate 31 and the second metal plate 32. The direction of the current flowing in the first metal plate 31 and the direction of the current flowing in the second metal plate 32 are opposite to one another.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power transmission coil unit.

Background Art

[0002] Patent Document 1 discloses a conventional power supply mat (power transmission device) for non-contact power supply, which is formed by connecting a plurality of sheet-like power transmission coil units configured to be able to transmit power to a vehicle in a non-contact manner.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When expanding the power supply mat by connecting power transmission coil units to each other as in the conventional power supply mat described above, as the expansion scale increases, the total value of the wiring lengths of the internal power wirings in each power transmission coil unit increases, so the influence of the parasitic inductance of the power wiring also increases. Therefore, due to the influence of the parasitic inductance, the resonance frequency of the power transmission coil unit may deviate from a preset desired resonance frequency (for example, the resonance frequency of the power receiving coil unit of a power supply target such as a moving body), and there is a risk that the transmission efficiency will decrease.

[0005] The present invention has been made paying attention to such problems, and an object thereof is to keep the parasitic inductance of the power transmission coil unit low.

Means for Solving the Problems

[0006] To solve the above problems, a power transmission coil unit according to one aspect of the present invention comprises a power transmission coil and a power supply member electrically connected to a power source and the power transmission coil, respectively, and supplying power supplied from the power source to the power transmission coil. The power supply member comprises a first metal plate and a second metal plate insulated via an insulating layer, and is configured such that when power is supplied from the power source, current flows to the power transmission coil through either the first metal plate or the second metal plate, and the current that has flowed through the power transmission coil returns to the power source through the other of the first metal plate or the second metal plate, and the direction of the current flowing through the first metal plate and the direction of the current flowing through the second metal plate are opposite. [Effects of the Invention]

[0007] According to this aspect of the present invention, the magnetic field formed by the current flowing through one of the first or second metal plates can be canceled out by the magnetic field formed by the current flowing through the other of the first or second metal plates. Therefore, the parasitic inductance of the power transmission coil unit can be kept low. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view of a power supply mat according to a first embodiment of the present invention. [Figure 2] Figure 2 is a schematic exploded perspective view of a power transmission coil unit according to a first embodiment of the present invention. [Figure 3] Figure 3 is a schematic perspective view of a substrate-type busbar according to the first embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view of a substrate-type busbar along the line IV-IV in Figure 3. [Figure 5A] Figure 5A is a schematic perspective view showing some components of a substrate-type busbar according to the first embodiment of the present invention. [Figure 5B] Figure 5B is a schematic perspective view showing some components of a substrate-type busbar according to the first embodiment of the present invention. [Figure 6] Figure 6 shows how the power transmission coil units are connected to each other. [Figure 7] Figure 7 shows a diagram illustrating that the direction of the current flowing through the first metal plate is opposite to the direction of the current flowing through the second metal plate. [Figure 8] Figure 8 is a schematic perspective view of a substrate-type busbar according to a second embodiment of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view of a substrate-type busbar along the IX-IX line in Figure 8. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the drawings. In the following description, similar components will be given the same reference numeral.

[0010] (First Embodiment) Figure 1 is a schematic perspective view of a power supply mat 100 according to a first embodiment of the present invention.

[0011] The power supply mat 100 is a mat configured to transmit power supplied from a power source, such as an external power source, to a power supply object in a non-contact manner, and comprises at least one sheet-shaped power transmission coil unit 1. The power supply object is not particularly limited in type, as long as it has a power receiving coil unit corresponding to the power transmission coil unit 1, and may be a mobile object such as a vehicle or micropallet, or it may be a communication device or a home appliance.

[0012] As shown in Figure 1, the power transmission coil units 1 are configured to be connectable to one another, thereby allowing the power supply mat 100 to be freely expanded. The details of the power transmission coil units 1 will be described below with reference to Figures 2 to 6.

[0013] Figure 2 is a schematic exploded perspective view of the power transmission coil unit 1. For convenience, in the following explanation, the side of the power transmission coil unit 1 on which the power to be supplied is placed will be referred to as the front side, and the opposite side will be referred to as the back side.

[0014] The power transmission coil unit 1 includes one or more power transmission coils 2, a substrate-type bus bar 3 disposed below the power transmission coils 2, and a cover 4. At this time, for example, a sheet-shaped ferrite can be interposed between the power transmission coils 2 and the substrate-type bus bar 3.

[0015] The power transmission coil 2 forms a resonance circuit together with, for example, a capacitor (not shown), and performs non-contact power transmission by magnetic field resonance coupling (magnetic field resonance) to a power supply target disposed above the power transmission coil unit 1. Note that the power transmission method is not limited to magnetic field resonance coupling, and other power transmission methods such as magnetic field coupling (electromagnetic induction), electric field coupling, and electric field resonance coupling (electric field resonance) may also be used. In FIG. 2, nine power transmission coils 2 are shown.

[0016] The substrate-type bus bar 3 is electrically connected to each of a power supply (not shown) and the power transmission coil 2, and supplies the power supplied from the power supply to the power transmission coil 2. Details of the substrate-type bus bar 3 will be described later with reference to FIGS. 3 to 6.

[0017] The cover 4 is disposed on the front side of the power transmission coil 2 and the back side of the substrate-type bus bar 3, respectively, and protects the power transmission coil 2 and the substrate-type bus bar 3. In the present embodiment, the cover 4 is formed of a flexible member so that the power transmission coil unit 1 can be wound or bent into a roll shape.

[0018] FIG. 3 is a schematic perspective view of the substrate-type bus bar 3. FIG. 4 is a schematic cross-sectional view of the substrate-type bus bar 3 taken along line IV-IV in FIG. 3. FIGS. 5A and 5B are schematic perspective views showing some components of the substrate-type bus bar 3, respectively.

[0019] As shown in Figure 4, the substrate-type busbar 3 comprises a first metal plate 31, a second metal plate 32, a front-side insulating plate 33 positioned on the front side of the first metal plate 31, an intermediate insulating plate 34 positioned between the first metal plate 31 and the second metal plate 32, and a back-side insulating plate 35 positioned on the back side of the second metal plate 32. Figure 5A is a perspective view showing the substrate-type busbar 3 with the front-side insulating plate 33, the first metal plate 31, and the intermediate insulating plate 34 removed (i.e., a perspective view showing the back-side insulating plate 35 and the second metal plate 32 stacked), and Figure 5B is a perspective view showing the substrate-type busbar 3 with only the front-side insulating plate 33 removed (i.e., a perspective view showing the back-side insulating plate 35, the second metal plate 32, the intermediate insulating plate 34, and the first metal plate 31 stacked).

[0020] The substrate-type busbar 3 is insulated from components located on the front side of the substrate-type busbar 3 (the power transmission coil 2 in this embodiment) by the front-side insulating plate 33, and similarly insulated from components located on the back side of the substrate-type busbar 3 (the cover 4 in this embodiment) by the back-side insulating plate 35. The first metal plate 31 and the second metal plate 32 are insulated from each other by an intermediate insulating plate 34 placed between them.

[0021] As shown in Figure 3, the board-type busbar 3 includes a pair of power supply terminals 6 for supplying power from a power source to the board-type busbar 3, and a pair of power transmission coil connection terminals 7 for supplying the power supplied to the board-type busbar 3 to the power transmission coil 2 located on the front side of the board-type busbar 3. Figure 3 shows an example of a board-type busbar 3 that includes two sets of power supply terminals 6 and nine sets of power transmission coil connection terminals 7.

[0022] The power supply terminal 6 is used as a terminal for electrically connecting the board-type busbar 3, and by extension the power transmission coil unit 1, to the power source, and is also used as a terminal for electrically connecting the power transmission coil units 1 to each other when connecting them together.

[0023] One of the pair of power supply terminals 6 (hereinafter referred to as the "first power supply terminal") 6A is electrically connected to the first metal plate 31, and when the power transmission coil unit 1 is connected to a power source, it is electrically connected to one of the pair of output terminals for voltage application of the power source, for example, via a power supply line. Also, as shown in Figure 6, for example, when connecting two power transmission coil units 1 together, the first power supply terminal 6A is electrically connected to the first power supply terminal 6A of the substrate-type busbar 3 of the other power transmission coil unit 1 being connected, for example, via a thin conductive fastener 8.

[0024] On the other hand, the other terminal of the pair of power supply terminals 6 (hereinafter referred to as the "second power supply terminal") 6B is electrically connected to the second metal plate 32, and when the power transmission coil unit 1 is connected to a power source, it is electrically connected to the other output terminal of the pair of voltage-applying output terminals of the power source, for example, via a power supply line. Also, as shown in Figure 6, for example, when connecting power transmission coil units 1 to each other, the second power supply terminal 6B is electrically connected to the second power supply terminal 6B of the substrate-type busbar 3 of the power transmission coil unit 1 to be connected, for example, via a thin conductive fastener 8. In this embodiment, as shown in Figures 3 and 6, the power supply terminals 6 are provided at both the left and right ends of the substrate-type busbar 3, but they may also be provided at both the top and bottom ends. In this way, the power transmission coil units 1 can be connected not only left and right but also top and bottom, so the power supply mat 100 can be expanded in all directions.

[0025] The power transmission coil connection terminal 7 is used as a terminal for electrically connecting the board-type busbar 3 to the power transmission coil 2.

[0026] One of the pair of power transmission coil connection terminals 7 (hereinafter referred to as the "first power transmission coil connection terminal") 7A is electrically connected to the first metal plate 31 and to one end of the power transmission coil 2.

[0027] On the other hand, the other terminal of the pair of power transmission coil connection terminals 7 (hereinafter referred to as the "second power transmission coil connection terminal") 7B is electrically connected to the second metal plate 32 and to the other end of the power transmission coil 2.

[0028] With this configuration, when current is supplied from the power source to the first metal plate 31 via the first power supply terminal 6A, the current flows through the first metal plate 31 and is supplied from the first metal plate 31 to the power transmission coil 2 via the first power transmission coil connection terminal 7A. The current that has flowed through the power transmission coil 2 then flows into the second metal plate 32 via the second power transmission coil connection terminal 7B, flows through the second metal plate 32 and returns to the power source from the second metal plate 32 via the second power supply terminal 6B. Naturally, when current is supplied from the power source to the second metal plate 32 via the second power supply terminal 6B, the current flow is reversed.

[0029] In this embodiment, as shown in Figure 7, the positions of the pair of power supply terminals 6 on the substrate-type busbar 3 are determined such that the direction of the current flowing through the first metal plate 31 and the direction of the current flowing through the second metal plate 32 are opposite. This provides the following advantages.

[0030] In other words, as shown in Figure 7, an insulating layer (an intermediate insulating plate 34 in this embodiment) is provided between the first metal plate 31 and the second metal plate 32, each having a width, and the direction of the current flowing through the first metal plate 31 and the direction of the current flowing through the second metal plate 32 are reversed, thereby making it possible to reverse the direction of the magnetic field formed by the current flowing through the first metal plate 31 (counterclockwise in the example of Figure 7) and the direction of the magnetic field formed by the current flowing through the second metal plate 32 (clockwise in the example of Figure 7).

[0031] This allows the magnetic field formed by the current flowing through one of the metal plates, the first metal plate 31 or the second metal plate 32, to be canceled out by the magnetic field formed by the current flowing through the other metal plate. As a result, the parasitic inductance of the power transmission coil unit 1, that is, the inductance of the power path inside the power transmission coil unit 1 for supplying power from the power source to the power transmission coil 2, can be reduced.

[0032] Furthermore, the shorter the distance in the thickness direction between the first metal plate 31 and the second metal plate 32, that is, the thinner the intermediate insulating plate 34, the greater the magnetic field cancellation effect. For this reason, it is desirable to make the thickness of the intermediate insulating plate 34 as thin as possible while maintaining insulation between the first metal plate 31 and the second metal plate 32.

[0033] The power transmission coil unit 1 according to this embodiment, as described above, comprises a power transmission coil 2 and a substrate-type busbar 3 (power supply member) that is electrically connected to the power source and the power transmission coil 2, respectively, and supplies power supplied from the power source to the power transmission coil 2. The substrate-type busbar 3 comprises a first metal plate 31 and a second metal plate 32 insulated via an intermediate insulating plate 34 (insulating layer). When power is supplied from the power source, current flows to the power transmission coil 2 through either the first metal plate 31 or the second metal plate 32, and the current that has flowed through the power transmission coil 2 returns to the power source through the other of the first metal plate 31 or the second metal plate 32. Furthermore, the direction of the current flowing through the first metal plate 31 and the direction of the current flowing through the second metal plate 32 are opposite.

[0034] This allows the magnetic field formed by the current flowing through one of the metal plates, the first metal plate 31 or the second metal plate 32, to be canceled out by the magnetic field formed by the current flowing through the other metal plate. As a result, the parasitic inductance of the power transmission coil unit 1, that is, the inductance of the power path within the power transmission coil unit 1 for supplying power from the power source to the power transmission coil 2, can be reduced. Furthermore, even when the power transmission coil units 1 are connected to each other to expand the power supply mat 100, the effect of parasitic inductance is small, so it is possible to suppress deviations of the resonant frequency of the power transmission coil unit 1 from a preset desired resonant frequency (for example, the resonant frequency of the receiving coil unit of the power supply target such as a mobile device), thereby suppressing a decrease in transmission efficiency.

[0035] The board-type busbar 3 according to this embodiment includes, in detail, a pair of power supply terminals 6 for supplying power from a power source to the board-type busbar 3, and a pair of power transmission coil connection terminals 7 for supplying the power supplied to the board-type busbar 3 to the power transmission coil 2. One of the pair of power supply terminals 6, the first power supply terminal 6A, is used as a terminal for electrically connecting to one output terminal of the power source and is electrically connected to the first metal plate 31, while the other, the second power supply terminal 6B, is used as a terminal for electrically connecting to the other output terminal of the power source and is electrically connected to the second metal plate 32. In addition, one of the pair of power transmission coil connection terminals 7, the first power transmission coil connection terminal 7A, is used as a terminal for electrically connecting to one end of the power transmission coil 2 and is electrically connected to the first metal plate 31, while the other, the second power transmission coil connection terminal 7B, is used as a terminal for electrically connecting to the other end of the power transmission coil 2 and is electrically connected to the second metal plate 32. The positions of the pair of power supply terminals 6 on the substrate-type busbar 3 are determined such that the direction of the current flowing through the first metal plate 31 and the direction of the current flowing through the second metal plate 32 are opposite.

[0036] In this embodiment, the pair of power supply terminals 6 of the substrate-type busbar 3 are also used as terminals for electrically connecting another power transmission coil unit 1. This makes it easy to expand the power supply mat 100 by connecting power transmission coil units together.

[0037] (Second Embodiment) Next, a second embodiment of the present invention will be described. This embodiment differs from the first embodiment in that a heat dissipation material 36 for dissipating heat from the power transmission coil is provided on the substrate-type busbar 3. The following will focus on explaining this difference.

[0038] Figure 8 is a schematic perspective view of the substrate-type busbar 3 according to this embodiment. Figure 9 is a schematic cross-sectional view of the substrate-type busbar 3 along the line IX-IX in Figure 8.

[0039] As shown in Figures 8 and 9, the substrate-type busbar 3 according to this embodiment includes a heat dissipation material 36 that penetrates from the front side to the back side of the substrate-type busbar 3. As the heat dissipation material 36, a metal with high thermal conductivity, such as aluminum, can be used.

[0040] In this embodiment, the heat dissipation material 36 is attached to four locations in the center of the substrate-type busbar 3, while ensuring insulation from the first metal plate 31 and the second metal plate 32. However, the heat dissipation material 36 can be attached to any position and range on the substrate-type busbar 3, as long as it does not obstruct the flow of current through the first metal plate 31 and the second metal plate 32.

[0041] In this way, by providing a heat dissipation material 36 that penetrates the substrate-type busbar 3 from its front side to its back side, the heat from the power transmission coil 2 located on the front side of the substrate-type busbar 3 can be released by the heat dissipation material 36 to the back side of the substrate-type busbar 3, and consequently to the back side of the power transmission coil unit 1.

[0042] The power transmission coil 2 of the power transmission coil unit 1 according to this embodiment described above is arranged on the surface side of the substrate-type busbar 3 (power supply member), and the substrate-type busbar 3 is equipped with a heat dissipation material 36 that penetrates from the surface side to the back side of the substrate-type busbar 3.

[0043] Specifically, the substrate-type busbar 3 comprises a front-side insulating plate 33 positioned on the front side of the first metal plate 31, an intermediate insulating plate 34 positioned between the first metal plate 31 and the second metal plate 32, and a back-side insulating plate 35 positioned on the back side of the second metal plate 32. The heat dissipation material 36 is attached to the substrate-type busbar 3 so as to penetrate the front-side insulating plate 33, the first metal plate 31, the intermediate insulating plate 34, the second metal plate 32, and the back-side insulating plate 35 to dissipate the heat from the power transmission coil 2 to the back side of the substrate-type busbar 3.

[0044] This allows the heat from the power transmission coil 2, which is positioned on the surface side of the substrate-type busbar 3, to be released by the heat dissipation material 36 to the back side of the substrate-type busbar 3, and consequently to the back side of the power transmission coil unit 1.

[0045] Furthermore, since the power transmission coil 2 is positioned on the surface side of the substrate-type busbar 3, and the front insulating plate 33, first metal plate 31, intermediate insulating plate 34, second metal plate 32, and back insulating plate 35 are arranged in that order from the surface side, the magnetic field generated by the power transmission coil 2 that is directed toward the back side of the power transmission coil unit 1 can be blocked by the first metal plate 31 and the second metal plate 32. Therefore, it is possible to prevent accidental overheating of any components buried in the ground when using the power transmission coil unit 1 and, consequently, the power supply mat 100. Moreover, the greater the combined thickness of the first metal plate 31 and the second metal plate 32, the greater the magnetic field blocking effect.

[0046] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of symbols]

[0047] 1. Power transmission coil unit 2. Transmission coil 3. Circuit board type busbar (power supply component) 6 Power supply terminal 6A 1st power supply terminal 6B 2nd power supply terminal 7 Terminals for connecting power transmission coils 7A Terminal for connecting the first power transmission coil 7B Terminal for connecting the second power transmission coil 31 1st metal plate 32 Second metal plate 33 Front side insulating plate 34 Intermediate insulating plate 35. Insulating plate on the back side 36 Heat dissipation material

Claims

1. Transmission coil and A power supply member is electrically connected to the power source and the power transmission coil, respectively, and supplies power supplied from the power source to the power transmission coil. A power transmission coil unit for contactless power supply, comprising: The aforementioned power supply member is It comprises a first metal plate and a second metal plate insulated via an insulating layer, When power is supplied from the power source, current flows to the power transmission coil through either the first metal plate or the second metal plate, and the current flowing through the power transmission coil returns to the power source through the other of the first metal plate or the second metal plate, and the direction of the current flowing through the first metal plate and the direction of the current flowing through the second metal plate are opposite. Power transmission coil unit.

2. The aforementioned power supply member is It has a pair of power supply terminals for supplying power from the power source to the power supply member, and a pair of power transmission coil connection terminals for supplying the power supplied to the power supply member to the power transmission coil, One of the pair of power supply terminals, the first power supply terminal, It is used as a terminal for electrically connecting to one of the output terminals of the power supply and is electrically connected to the first metal plate. The other of the pair of power supply terminals, the second power supply terminal, It is used as a terminal for electrically connecting to the other output terminal of the power supply and is electrically connected to the second metal plate. One of the pair of terminals for connecting the power transmission coils, the first terminal for connecting the power transmission coil, It is used as a terminal for electrically connecting to one end of the power transmission coil and is electrically connected to the first metal plate. The other of the pair of terminals for connecting the power transmission coils, the second terminal for connecting the power transmission coil, It is used as a terminal for electrically connecting to the other end of the power transmission coil and is electrically connected to the second metal plate. The positions of the pair of power supply terminals on the power supply member are determined such that the direction of the current flowing through the first metal plate and the direction of the current flowing through the second metal plate are opposite. The power transmission coil unit according to claim 1.

3. The pair of power supply terminals are also used as terminals for electrically connecting another power transmission coil unit. The power transmission coil unit according to claim 2.

4. The power transmission coil is positioned on the surface side of the power supply member. The power supply member includes a heat dissipation material that penetrates from the front side to the back side of the power supply member. A power transmission coil unit according to any one of claims 1 to 3.

5. The aforementioned power supply member is A front insulating plate is placed on the front side of the first metal plate, An intermediate insulating plate, which serves as the insulating layer, is disposed between the first metal plate and the second metal plate. A back insulating plate is placed on the back side of the second metal plate, Equipped with, The aforementioned heat dissipation material is The heat from the power transmission coil is dissipated to the back side of the power supply member by penetrating the front insulating plate, the first metal plate, the intermediate insulating plate, the second metal plate, and the back insulating plate. The power transmission coil unit according to claim 4.

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