Lead wires, contactless power transmission devices, and contactless power supply systems

Abstract

To provide a lead wire that can reduce resistance without increasing the width of the conductor foil. [Solution] The lead wire (12) of the present invention is characterized by comprising a plurality of conductor foil pairs (12c) each having a first conductor foil (12a) and a second conductor foil (12b), and an insulator (12d) disposed between the main surface of the first conductor foil (12a) and the main surface of the second conductor foil (12b), and between the plurality of conductor foil pairs (12c).

Description

Technical Field

[0001] The present invention relates to a lead wire, a non-contact power transmission device having the lead wire, and a non-contact power supply system having the non-contact power transmission device.

Background Art

[0002] Conventionally, non-contact power supply is known. In non-contact power supply, power is generated in a coil on the power receiving side by the action of a coil on the power transmission side. A battery is connected to the coil on the power receiving side, and power is stored in the battery. Patent Document 1 discloses a power supply coil unit (non-contact power transmission device) used for non-contact power supply.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a non-contact power transmission device as described in Patent Document 1, a lead wire (power supply cable) is used to transmit power from an AC power supply (high-frequency power supply) to a coil. The inventors of the present invention have devised to make the conductor of the lead wire a thin conductor foil in order to suppress the conductor resistance. Such a lead wire can reduce the adverse effect due to the skin effect because the conductor foil is thin, and can reduce the conductor resistance.

[0005] In order to further reduce the resistance of the lead wire whose conductor is the conductor foil, it is conceivable to increase the width of the conductor foil. However, when the width of the conductor foil is increased, the diameter of a protective tube (FEP tube) that houses and protects the lead wire during laying of the lead wire becomes large, and the required laying space becomes large.

[0006] The object of the present invention is to provide a lead wire that can reduce resistance without increasing the width of the conductor foil, a non-contact power transmission device having the lead wire, and a non-contact power supply system having the non-contact power transmission device. [Means for solving the problem]

[0007] According to one aspect of the present invention for solving the above problems, A plurality of pairs of conductor foils, each having a first conductor foil and a second conductor foil, An insulator is disposed between the main surface of the first conductor foil and the main surface of the second conductor foil, and between the plurality of pairs of conductor foils, A lead wire is provided, characterized by having [a certain feature].

[0008] According to another aspect of the present invention for solving the above problems, An AC power supply having a first terminal and a second terminal, Coil unit and Lead wires that electrically connect the AC power supply and the coil unit, It has, The aforementioned lead wire is the lead wire described above. The plurality of conductor foil pairs are arranged so that the first conductor foil and the second conductor foil alternate. The first conductor foil of each of the plurality of conductor foil pairs is electrically connected to the first terminal of the AC power supply. The second conductor foil of each of the plurality of conductor foil pairs is electrically connected to the second terminal of the AC power supply, A contactless power transmission device is provided.

[0009] According to another aspect of the present invention for solving the above problems, A contactless power supply system is provided, characterized by having the above-mentioned contactless power transmission device. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a lead wire capable of reducing the AC resistance without increasing the width of the conductor foil, a non-contact power transmission device having the lead wire, and a non-contact power supply system having the non-contact power transmission device.

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1A is a schematic diagram of a non-contact power supply system according to an embodiment, and FIG. 1B is a schematic diagram of a non-contact power transmission device. [Figure 2] FIGS. 2A to C are cross-sectional views of a lead wire according to an embodiment. [Figure 3] FIG. 3 is a graph showing the relationship between frequency and conductor resistance. [Figure 4] FIG. 4 is a graph obtained by partially enlarging the graph of FIG. 3.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, a non-contact power supply system, a non-contact power transmission device, and a lead wire according to an embodiment of the present invention will be described. However, the embodiments shown below are merely examples, and the present invention is not limited to the embodiments. The non-contact power supply system and the non-contact power transmission device of the present invention can be used, for example, to charge a battery mounted on an electric vehicle or a plug-in hybrid vehicle in a non-contact state. In this specification, the “~” indicating a numerical range includes the upper limit value and the lower limit value within the numerical range.

[0013] [Non-contact Power Supply System] FIG. 1A is a schematic diagram showing a state in which non-contact power supply is being performed to a battery 3 of an electric vehicle 2 using a non-contact power supply system 1 according to the present embodiment. FIG. 1B is a schematic diagram showing the internal structure of a non-contact power transmission device 10 included in the non-contact power supply system 1 shown in FIG. 1A.

[0014] As shown in FIGS. 1A and 1B, the non-contact power transmission device 10 includes a power source 11, a lead wire 12, and a coil unit 13. In the non-contact power transmission device 10, the current supplied from the power source 11 flows through the lead wire 12 and then flows into the coil unit 13. Due to the action of the coil unit 13 through which the current flows, a current is generated in the coil 4 for power reception that the electric vehicle 2 has, and the battery 3 that the electric vehicle 2 has is non-contact power-fed.

[0015] (Non-contact power transmission device) Hereinafter, the non-contact power transmission device 10 included in the non-contact power feeding system 1 will be described. As described above, the non-contact power transmission device 10 includes a power source 11, a lead wire 12, and a coil unit 13. Here, the lead wire 12 according to the present embodiment has a conductor foil without having a litz wire. Details of the lead wire 12 will be described later. Hereinafter, each component included in the non-contact power transmission device 10 will be described.

[0016] 〈Power source) The power source 11 is an electrical energy source of the non-contact power transmission device 10. In the present embodiment, the power source 11 is an AC power source, and the current supplied to the circuit is an alternating current. From the viewpoint of efficient power feeding, it is preferable that the power source 11 supplies an alternating current having a resonance frequency of the non-contact power feeding system 1. When the non-contact power transmission device 10 is used in the non-contact power feeding system 1 of the electric vehicle 2, the resonance frequency is generally around 85 kHz (80 kHz to 90 kHz). Therefore, it is preferable that the power source 11 can supply an alternating current around 85 kHz (80 to 90 kHz), and it is more preferable that the power source 11 can supply an alternating current of 85 kHz.

[0017] 〈Lead wire〉 As shown in FIG. 1B, the lead wire 12 is electrically connected to the power source 11 and the coil unit 13 to form a circuit. FIGS. 2A to 2C are cross-sectional views of such a lead wire 12, specifically, a cross-sectional view taken along the line A-A of FIG. 1B.

[0018] As shown in Figures 1B and 2A, the lead wire 12 has multiple pairs of conductor foils 12c, each having a first conductor foil 12a and a second conductor foil 12b. The lead wire 12 also has an insulator 12d placed between the first conductor foil 12a and the second conductor foil 12b, and another insulator 12d placed between the multiple pairs of conductor foils 12c. In this embodiment, the lead wire 12 also has a sheath 12e. Having multiple pairs of conductor foils 12c in the lead wire 12 reduces the AC resistance without increasing the width of the first conductor foil 12a and the second conductor foil 12b. Furthermore, this allows the lead wire 12 to be housed in the protective tube 14 without increasing its diameter, as will be described later. The following describes each component of the lead wire 12.

[0019] <<First conductor foil and second conductor foil>> The first conductor foil 12a and the second conductor foil 12b are conductors of the lead wire 12. In this specification, "conductor foil" means a plate-shaped conductor. The length (length in the direction of extension of the lead wire 12) and width (length in the direction perpendicular to the direction of extension and thickness of the lead wire 12) of the conductor foil are greater than the thickness of the conductor foil. The first conductor foil 12a and the second conductor foil 12b may be made of a conductive material, for example, a metal. Examples of metals include copper and copper alloys. In this embodiment, the material of the first conductor foil 12a and the second conductor foil 12b is copper. That is, the first conductor foil 12a and the second conductor foil 12b are copper foils. Furthermore, the surfaces of the first conductor foil 12a and the second conductor foil 12b are smooth.

[0020] The first conductor foil 12a and the second conductor foil 12b extend along the direction in which the lead wire 12 extends. Furthermore, the first conductor foil 12a and the second conductor foil 12b are arranged side-by-side such that one of each of their two main surfaces faces the other. Here, "main surface" refers to the two relatively wide surfaces (the front surface and the back surface) of the conductor foil. The main surface is perpendicular to the thickness direction of the conductor foil and extends in the width and length directions of the conductor foil.

[0021] The distance between the first conductor foil 12a and the second conductor foil 12b, which are arranged side by side as described above (the distance between the two opposing main surfaces), is preferably set so that the increase in AC resistance when an AC current flows is suppressed by the proximity effect. From this viewpoint, the distance between the first conductor foil 12a and the second conductor foil 12b is preferably 1.5 mm or less. On the other hand, if the distance between the first conductor foil 12a and the second conductor foil 12b is too close, the possibility of a short circuit increases. From this viewpoint, the distance between the first conductor foil 12a and the second conductor foil 12b is preferably, for example, 0.5 mm or more.

[0022] Each of the multiple conductor foil pairs 12c has a first conductor foil 12a and a second conductor foil 12b, and the multiple conductor foil pairs 12c are stacked so that the first conductor foil 12a and the second conductor foil 12b alternate. The first conductor foil 12a is electrically connected to the first terminal, which is one of the two terminals of the AC power supply, and the second conductor foil 12b is electrically connected to the second terminal, which is the other of the two terminals. As a result, the current from the power supply 11, which is an AC power supply, flows in opposite directions through the first conductor foil 12a and the second conductor foil 12b. As a result, the AC resistance is reduced due to the proximity effect.

[0023] The number of laminated conductive foil pairs 12c is not particularly limited. For example, the number of conductive foil pairs 12c may be two or three. In this embodiment, the number of laminated conductive foil pairs 12c is two.

[0024] The thicknesses of the first conductor foil 12a and the second conductor foil 12b are preferably set to suppress the increase in AC resistance due to the skin effect when an AC current is passed through them. The skin effect increases as the frequency of the AC current increases, thus increasing resistance. The thicknesses of the first conductor foil 12a and the second conductor foil 12b can be appropriately set according to the frequency of the AC current.

[0025] For example, when the contactless power transmission device 10 is used to charge an electric vehicle 2, an alternating current with a resonant frequency of around 85 kHz (e.g., 80 kHz to 90 Hz) flows from the power supply 11. When a current with a frequency of around 85 kHz flows through the copper foil, the skin depth is 0.227 mm. Skin depth is the depth of the portion of the copper foil where the current flowing is 37% of the surface through which the maximum current flows. For this reason, in order to suppress the skin effect, the thickness of the first conductor foil 12a and the second conductor foil 12b is preferably, for example, 0.5 mm or less. On the other hand, if they are too thin, the cross-sectional area becomes small, making it difficult for current to flow. From this viewpoint, the thickness of the first conductor foil 12a and the second conductor foil 12b is preferably, for example, 0.1 mm or more.

[0026] The widths of the first conductor foil 12a and the second conductor foil 12b are not particularly limited. The upper limit of the width of the first conductor foil 12a and the second conductor foil 12b is, for example, 100 mm or less, in relation to the inner diameter of the protective tube 14, and the lower limit of the width is, for example, 10 mm or more.

[0027] The manner in which the first conductor foil 12a and the second conductor foil 12b are electrically connected to the first terminal 11a and the second terminal 11b of the power supply 11 is not particularly limited. For example, as shown in Figure 1B, one end of each of the first conductor foil 12a and the second conductor foil 12b may be connected to the first terminal 11a and the second terminal 11b of the power supply 11 via rivets 6. Alternatively, for example, holes may be made in the first conductor foil 12a and the second conductor foil 12b and they may be screwed or bolted to the first terminal 11a and the second terminal 11b, respectively. The manner in which the first conductor foil 12a and the second conductor foil 12b are electrically connected to the coil unit 13 is also not particularly limited. The first conductor foil 12a and the second conductor foil 12b may be connected to the first terminal and the second terminal of the coil unit 13 in the same manner as described above.

[0028] <<Insulator>> The insulator 12d is placed between the first conductor foil 12a and the second conductor foil 12b, and between multiple pairs of conductor foils 12c, to perform an insulating function and prevent short circuits between the first conductor foil 12a and the second conductor foil 12b, and between multiple pairs of conductor foils 12c. The insulator 12d is not particularly limited as long as it can perform this function. The insulator 12d is, for example, plate-shaped and extends along the direction in which the lead wire 12 extends.

[0029] In this embodiment, as shown in Figure 2A, a first conductor foil 12a is placed between two tape-shaped insulators 12d, and similarly, a second conductor foil 12b is placed between two tape-shaped insulators 12d, so that the first conductor foil 12a and the second conductor foil 12b are alternately laminated. As a result, there are two layers of insulators 12d between the first conductor foil 12a and the second conductor foil 12b, and also two layers of insulators 12d between the two pairs of conductor foils 12c.

[0030] As shown in Figure 2A, the widthwise length of the insulator 12d is longer than the widthwise length of the first conductor foil 12a and the widthwise length of the second conductor foil 12b. As a result, when the insulator 12d is laminated with the first conductor foil 12a or the second conductor foil 12b, the insulator 12d has ends that protrude on both sides in the widthwise direction relative to the first conductor foil 12a or the second conductor foil 12b. By joining the protruding ends, the first conductor foil 12a and the second conductor foil 12b covered with the insulator 12d can be obtained. The method of bonding the ends of the insulator 12d is not particularly limited. Examples of bonding methods include bonding using adhesives, heat fusion, ultrasonic welding, etc.

[0031] The configuration in which the insulator 12d is placed between the first conductor foil 12a and the second conductor foil 12b is not limited to the example in Figure 2A, but may also be as shown in Figure 2B, for example. That is, as shown in Figure 2B, the periphery of the first conductor foil 12a and the second conductor foil 12b are covered with an insulator 12d. Then, the first conductor foil 12a and the second conductor foil 12b covered with the insulator 12d are stacked. In this way, the insulator 12d may be placed between the first conductor foil 12a and the second conductor foil 12b.

[0032] Alternatively, the arrangement may be as shown in Figure 2C. That is, as shown in Figure 2C, an insulator 12d may be placed between the first conductor foil 12a and the second conductor foil 12b, and the first conductor foil 12a and the second conductor foil 12b may be covered with the insulator 12d from each side. In this case, there is one layer of insulator 12d between the first conductor foil 12a and the second conductor foil 12b, and there are two layers of insulator 12d between multiple pairs of conductor foils 12c.

[0033] The insulator 12d may be formed by extrusion molding or by applying tape.

[0034] The material of the insulator 12d is not particularly limited as long as it can perform insulating functions. Examples of materials for the insulator 12d include resins. Examples of resins include thermoplastic resins. Examples of materials for the insulator 12d include thermoplastic resins, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), and polypropylene (PP).

[0035] The thickness of the insulator 12d placed between the first conductor foil 12a and the second conductor foil 12b is preferably such that a proximity effect occurs between the first conductor foil 12a and the second conductor foil 12b. From this viewpoint, the thickness of the insulator 12d placed between the first conductor foil 12a and the second conductor foil 12b is preferably 1.0 mm or less. On the other hand, if the thickness of the insulator 12d is too thin, sufficient insulation function may not be obtained. From this viewpoint, the thickness of the insulator 12d placed between the first conductor foil 12a and the second conductor foil 12b is preferably 0.1 mm or more.

[0036] The thickness of the insulator 12d placed between multiple pairs of conductor foils 12c is preferably such that a proximity effect occurs between the first conductor foil 12a of one pair of conductor foils 12c and the second conductor foil 12b of the other pair of conductor foils 12c. From this viewpoint, the thickness of the insulator 12d placed between multiple pairs of conductor foils 12c is preferably 1.0 mm or less. On the other hand, if the thickness of the insulator 12d is too thin, sufficient insulation function may not be obtained. From this viewpoint, the thickness of the insulator 12d between multiple pairs of conductor foils 12c is preferably 0.1 mm or more.

[0037] <sheath> The sheath 12e covers the lead wire 12. The sheath 12e has an arbitrary configuration and may or may not be present. In this embodiment, the lead wire 12 has the sheath 12e. The lead wire 12 covered with the sheath 12e is used as a lead cable.

[0038] The sheath 12e extends in the direction of extension of the lead wire 12. The material of the sheath 12e is preferably insulating. Examples of materials for the sheath 12e include resins. Examples of resins include thermoplastic resins. The material of the sheath 12e may be the same as the material of the insulator 12d.

[0039] <Protection tube> The protective conduit 14 covers the lead wire 12. When the lead wire 12 is used for contactless power supply to an electric vehicle 2, the lead wire 12 may be buried underground. Therefore, it is preferable that the protective conduit 14 is suitable for underground burial. The protective conduit 14 is, for example, an FEP conduit.

[0040] <Coil Unit> The coil unit 13 is electrically connected to the lead wire 12. When current is supplied to the coil unit 13 via the lead wire 12, a magnetic field is generated in the coil 13a of the coil unit 13, and this generated magnetic field acts on the coil 4 for receiving power, generating an electric current.

[0041] As shown in Figure 1B, in this embodiment, the coil unit 13 includes a coil 13a, a capacitor 13b, and a housing 13c. Each of these will be described below.

[0042] Coil 13a is made by winding a linear conductor. In this embodiment, the linear conductor is enameled wire, and the enameled wire is wound in a planar manner.

[0043] The basic design of the coil 13a, such as the number of turns, should be adjusted as appropriate in relation to other components to achieve the desired resonant frequency (e.g., 85 kHz). In this embodiment, the coil 13a is sealed with resin within the housing 13c.

[0044] Capacitor 13b is electrically connected to coil 13a and, together with coil 13a, constitutes a resonant circuit of the contactless power transmission device 10, generating a resonance phenomenon. The resonant frequency of the resonant circuit is determined mainly by the inductance of coil 13a and the capacitance of capacitor 13b. Therefore, it is preferable to set the combined capacitance of capacitor 13b so that the resonant frequency of the resonant circuit of the contactless power transmission device 10 approaches a desired frequency (e.g., 85 kHz). The number of capacitors 13b is not particularly limited and is set appropriately according to the required combined capacitance, etc. In this embodiment, multiple capacitors 13b are arranged on two separate substrates. The substrates on which the multiple capacitors 13b are arranged are housed in a predetermined space within the housing 13c, supported by a base.

[0045] Capacitor 13b may be connected in parallel or in series with coil 13a. In this embodiment, capacitor 13b is arranged in series with lead wire 12 and coil 13a. That is, capacitor 13b is placed between the first conductor foil 12a and the second conductor foil 12b and coil 13a.

[0046] <housing> The housing 13c houses the coil 13a and the capacitor 13b. Preferably, the housing 13c can protect the housed coil 13a and the resonant capacitor 13b from the external environment. In this embodiment, the coil unit 13 is buried underground. Therefore, it is preferable that the housing 13c can protect the coil 13a and the capacitor 13b underground. Specifically, it is preferable that the housing 13c has a waterproof function. Furthermore, it is preferable that the coil 13a and the capacitor 13b are sealed with resin inside the housing 13c. This makes the coil 13a and the capacitor 13b less susceptible to the effects of condensation and other factors. It also improves insulation performance.

[0047] The material of the housing 13c is not particularly limited as long as it adequately protects the coil 13a and capacitor 13b. Examples of materials for the housing 13c include polycarbonate, polypropylene, and polyphenylene sulfide (PPS). Examples of resins used to seal the coil 13a and capacitor 13b include silicone resin, epoxy resin, and urethane resin. From the viewpoint of heat resistance, silicone resin is preferred.

[0048] (effect) The lead wire 12 according to this embodiment has a plurality of conductor foil pairs 12c, each having a first conductor foil 12a and a second conductor foil 12b, and the plurality of conductor foil pairs 12c are laminated. As a result, the lead wire according to this embodiment can reduce AC resistance without increasing the width of the conductor foil. Therefore, the lead wire 12 according to this embodiment is suitable for wiring when there are limitations on the installation space. [Examples]

[0049] An experiment was conducted to investigate the difference in conductor resistance with respect to AC current frequency between lead wires using 1 to 3 layers of conductive foil pairs as the conductor and lead wires using Litz wire as the conductor. Copper foil with a thickness of 0.3 mm and a width of 50 mm was used as the conductive foil. On the other hand, 2 m of Litz wire was used, made by twisting together 2000 strands of 0.1 mm diameter enameled wire. Specifically, multiple strands were twisted together and then further twisted in multiple stages to obtain Litz wire.

[0050] (Lead wires in Sample 1, conductor foil pair: 1 layer) A 2m length of the above copper foil was covered with a 0.5mm thick resin tape, except for both ends and the center, to form an insulator and obtain a coated copper foil. The resin tape is made of polyethylene. The coated copper foil was folded in the middle along its length, and the two coated copper foils were overlapped so that they were in contact with each other to form the lead wire of Sample 1. In this lead wire of Sample 1, a 1mm thick insulator, derived from two 0.5mm thick tapes, is placed between the two copper foils. The conductor foil pair of the lead wire of Sample 1 is a single layer. The cross-sectional area of ​​the conductor of the lead wire of Sample 1 is 30mm². 2 That is the case.

[0051] (Lead wires in Sample 2, conductor foil pair: 2 layers) Four 1.05m long copper foils were prepared, and all but the ends were covered with the same resin tape as above to obtain four coated copper foils. The four coated copper foils were stacked so that they were in contact with each other, and holes were made in the ends not covered with tape. The four coated conductors were then fastened together with bolts to ensure electrical conductivity. This lead wire has two layers of conductor foil. In addition, a 1mm thick insulator, derived from two 0.5mm thick tapes, is placed between the two conductor foil pairs. The cross-sectional area of ​​the conductor in Sample 2 is 60mm². 2 That is the case.

[0052] (Lead wires in Sample 3, conductor foil pairs: 3 layers) Sample 3 was constructed in the same manner as Sample 2, except that six coated copper foils were obtained and laminated in the same manner as described above. This lead wire has three layers of conductor foil. The cross-sectional area of ​​the conductor of the lead wire in Sample 3 is 90 mm². 2 That is the case.

[0053] (Lead wires for Sample 4: Litz wire) For comparison, the lead wire of Sample 4, which has Litz wire, was obtained as follows: The 2m Litz wire mentioned above was bent in the middle along its length, creating a 1mm gap between the two bent Litz wires. The cross-sectional area of ​​the conductor of the lead wire of Sample 4 is 31.42mm². 2 That is the case.

[0054] (Connecting the lead wires of samples 1-4 to the AC power supply and measuring their resistance) In each of samples 1 to 3, the ends of the laminated conductor foils were alternately connected to the first and second terminals of the AC power supply, starting from the top. This resulted in current flowing in opposite directions through adjacent laminated conductor foils. On the other hand, in sample 4, one end of the Litz wire was connected to the first terminal and the other end to the second terminal. The conductor resistance was measured for each of the lead wires in samples 1 to 4 when currents with frequencies from 0 kHz to 2000 kHz were passed from the AC power supply. The results are shown in the graph in Figure 3.

[0055] As can be seen from Figure 3, the conductor resistance increased with increasing frequency in each sample. Also, samples 1-3 had lower conductor resistance than sample 4. This is presumed to be because, in samples 1-3, the thinness of the copper foil suppressed the adverse effects of the skin effect, where high-frequency currents concentrate on the surface of the conductor, thus suppressing the increase in resistance. Furthermore, it is presumed that the proximity effect was obtained because the copper foils were arranged side by side. In addition, as can be seen from the comparison of samples 1-3, the conductor resistance decreased as the number of layers of conductor foil pairs increased. This is because increasing the number of layers of conductor foil pairs increases the cross-sectional area of ​​the conductor.

[0056] The graph in Figure 4 is a partially enlarged version of the graph in Figure 3, showing the conductor resistance at frequencies from 0 to 200 kHz. When lead wires are used for contactless power supply in electric vehicles, the AC power supply carries a current at a frequency around 85 kHz, which is the resonant frequency. As can be seen from Figure 4, the same trend as in Figure 3 was observed at frequencies around 85 kHz. In other words, samples 1-3, which have conductor foil pairs, had lower conductor resistance than sample 4, which has litz wire. Furthermore, the conductor resistance decreased as the number of layers of conductor foil pairs increased.

[0057] From this, it was found that the lead wires of Samples 1-3 are suitable for use as lead wires for contactless power supply in electric vehicles. Furthermore, the lead wires of Samples 2 and 3 have lower conductor resistance without increasing their width compared to the lead wire of Sample 1. Therefore, it was found that lead wires with multiple conductor foil pairs laminated together are suitable for efficient power supply when there are limitations on installation space. [Industrial applicability]

[0058] The lead wire, contactless power transmission device, and contactless power supply system of the present invention can be used, for example, for contactless power supply in automobiles. Furthermore, the lead wire of the present invention may be used for applications other than contactless power supply systems and can be used in various devices that require power supply. [Explanation of Symbols]

[0059] 1. Contactless power supply system 2 Electric vehicles 3 batteries 4. 13a coil 6 rivets 10. Contactless power transmission device 11 Power supply 11a 1st terminal 11b 2nd terminal 12 Lead wires 12a First Conductor Foil 12b Second Conductor Foil 12c Conductor Foil Pair 12d insulator 12e Sheath 13 Coil Units 13b Capacitor 13c Housing 14 Protection tube

Claims

1. A plurality of pairs of conductor foils, each having a first conductor foil and a second conductor foil, An insulator is disposed between the main surface of the first conductor foil and the main surface of the second conductor foil, and between the plurality of pairs of conductor foils, A lead wire characterized by having the following features.

2. A lead wire according to claim 1, characterized in that, in each of the plurality of conductor foil pairs, the thickness of the first conductor foil and the second conductor foil are 0.1 mm to 0.5 mm.

3. A lead wire according to claim 1, characterized in that the distance between the first conductor foil and the second conductor foil is 0.5 mm to 1.5 mm.

4. A lead wire according to claim 1, characterized in that the first conductor foil and the second conductor foil are copper foils.

5. An AC power supply having a first terminal and a second terminal, Coil unit and Lead wires that electrically connect the AC power supply and the coil unit, It has, The lead wire is the lead wire described in any one of claims 1 to 4. The plurality of conductor foil pairs are arranged so that the first conductor foil and the second conductor foil alternate. The first conductor foil of each of the plurality of conductor foil pairs is electrically connected to the first terminal of the AC power supply. The second conductor foil of each of the plurality of conductor foil pairs is electrically connected to the second terminal of the AC power supply, Non-contact power transmission device.

6. A contactless power transmission device according to claim 5, characterized in that the frequency of the AC power supply is 80 to 90 kHz.

7. A contactless power supply system characterized by having the contactless power transmission device described in claim 5.

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