JP2022072731A - Coil device, power transmission device and power receiving device, and power transmission system - Google Patents

Abstract

To provide a coil device and the like capable of stable wireless power transmission while achieving further cost reduction by reducing the number of capacitors, in addition to weight reduction and cost reduction by using a coil consisting of a winding of a thin film conductor winding line.SOLUTION: A power receiving coil RC for non-contact power transmission by a magnetic field resonance method includes a series resonance capacitor CR1 in which a power receiving loop coil RL1 and a power receiving loop coil RL2 each of which is configured by winding a copper thin film wire are laminated with an insulating film sandwiched therebetween, and that is connected between the power receiving loop coil RL1 and the power receiving loop coil RL2, and a difference in inductance between the power receiving loop coil RL1 and the power receiving loop coil RL2 connected to the series resonance capacitor CR1 is set to be equal to or less than a predetermined threshold value.SELECTED DRAWING: Figure 2

Description

The present invention belongs to the technical fields of coil devices, power transmission devices and power receiving devices, and power transmission systems. More specifically, it belongs to the technical field of a coil device used for non-contact type power transmission by a magnetic field resonance method, a non-contact type power transmission device and a power receiving device using the coil device, and a power transmission system.

In recent years, electric vehicles equipped with storage batteries such as lithium-ion batteries have become widespread. In such an electric vehicle, the electric power stored in the storage battery is used to drive and move the motor, so that the storage battery is required to be charged efficiently. Therefore, as a method of charging the storage battery mounted on an electric vehicle without physically connecting a charging plug or the like, so-called wireless power transmission using a power receiving coil and a power transmission coil that are separated from each other and opposed to each other is used. Is being researched.

Here, as the wireless power transmission method, there are generally an electric field coupling method, an electromagnetic induction method, a magnetic field resonance method, and the like. When these methods are compared from the viewpoints of, for example, the frequency of power transmitted and received, the degree of positional freedom in each of the horizontal and vertical directions, and the transmission efficiency, wireless power for charging the storage battery mounted on the electric vehicle is used. As a transmission method, an electric field coupling method using a capacitor or a magnetic field resonance method using a coil is promising, and research and development on these are being actively carried out. Examples of the prior art document that discloses such a background technique include the following Patent Document 1. Patent Document 1 discloses a coil that transmits power by a magnetic field resonance method using a loop coil with one (1 turn) winding and an open coil with five and a half turns (5.5 turns). There is.

On the other hand, the above-mentioned wireless power transmission (contactless power supply) for electric vehicles requires transmission of high output power of at least 3.7 kW (that is, flowing through a coil). Therefore, if the resistance of the conductor (coil) becomes high as a result of passing such high output power (current), the loss as a coil becomes large due to the generation of Joule heat, and the efficiency of wireless power transmission is lowered. It will be.

Therefore, as a method for reducing the resistance caused by the loss of the coil, it is conceivable to configure the coil itself by using a stranded wire (so-called litz wire). However, considering that the power receiving coil is mounted on a private car, the configuration of the coil using the stranded wire leads to an increase in weight and a high price of the coil. As a conventional technique for solving this problem, for example, a core material in which a thin film conductor made of copper and an insulating layer are laminated is patterned and etched into the shape of the coil by using a so-called photolithography method. It is conceivable to manufacture a coil on the insulating layer in which a winding line made of a thin film conductor is wound in a plane.

On the other hand, the frequency of the power transmitted and received by the wireless power transmission is predetermined by, for example, by law for each device responsible for the wireless power transmission, and is set to a high frequency of 85 kHz in the case of power transmission to the electric vehicle. Here, it is generally known that when a high-frequency current is passed through a conductor, the current density is high on the surface of the conductor and decreases toward the center of the conductor. Regarding this point, the higher the frequency of the current, the more the current concentrates on the surface, and as a result, the AC resistance of the conductor increases. This phenomenon is known as the so-called "skin effect of conductors". In the following description, the AC resistance in the conductor when a high frequency current is passed through the conductor is simply referred to as "impedance". Then, in the wireless power transmission using the coil formed on the insulating layer described above, when a high output power is to be transmitted while using a high frequency (for example, 85 kilohertz) current, the high output power (current) is used. As a result of the current, the resistance of the conductor (the coil) becomes higher due to the skin effect, and the loss as the coil due to the Joule heat becomes larger, which also reduces the efficiency of wireless power transmission. It ends up.

Further, as an electrical phenomenon that reduces the efficiency of wireless power transmission as in the above skin effect, the so-called "conductor proximity effect" caused by the close proximity of thin film conductors in winding as a coil. Can be mentioned. Therefore, it is necessary to take measures against the increase in impedance due to this proximity effect.

At this time, as one method of reducing the impedance in the coil, for example, it is conceivable to widen the width (line width) of the thin film conductor constituting the coil by winding. Here, when a laminated coil is used for wireless power transmission by the magnetic field resonance method, the coil itself needs to have a necessary inductance. On the other hand, for example, there is a limit to widening the line width as the coil due to the limitation of the size when mounted on the electric vehicle, and therefore, if there is only one coil made of a thin film conductor, the coil is used. In other words, the required number of turns (in other words, the required inductance) cannot be obtained. For this reason, it becomes necessary to make a plurality of layers of coils formed by winding a winding line of a thin film conductor.

Here, in wireless power transmission by the magnetic field resonance method, it is required that the coil and the capacitor having the required inductance have symmetry on the circuit due to the requirement of stability in the resonance.

Japanese Unexamined Patent Publication No. 2011-2000

However, in the wireless power transmission by the magnetic field resonance method using the multi-layered coil, considering connecting a capacitor for each coil in order to ensure the symmetry, as a result, a capacitor having the same capacity is used as the coil. Only a few minutes are required, and there is a problem that the cost increases as a power transmission system that performs wireless power transmission.

Therefore, the present invention has been made in view of the above-mentioned problems, and one example of the problem is a capacitor in addition to weight reduction and cost reduction by using a coil composed of a coil of a winding line of a thin-film conductor. A coil device that can stably perform wireless power transmission, a non-contact type transmission device and power receiving device using the coil device, and a power transmission system while realizing further cost reduction by reducing the number of Is to provide.

In order to solve the above problems, the invention according to claim 1 is an even number of coils configured by winding a winding line made of a thin film conductor in a coil device for non-contact power transmission by a magnetic field resonance method. A coil comprising a coil laminated with an insulating layer interposed therebetween and a capacitance means for resonance connected between two coils laminated adjacent to each other, and connected to the capacitance means. The difference in inductance between the two coils is configured to be less than or equal to a preset threshold.

According to the first aspect of the present invention, an even number of coils each configured by winding a winding line made of a thin film conductor are laminated, and a capacitance means is provided between two coils laminated adjacent to each other. It is connected, and the difference in inductance between the two coils connected to the capacitive means is set to be equal to or less than the predetermined threshold value. Therefore, by connecting the capacitive means required for the magnetic field resonance method between two coils stacked adjacent to each other and having an inductance difference of less than the predetermined threshold, weight reduction and weight reduction by using a winding line made of a thin film conductor can be achieved. In addition to cost reduction, non-contact power transmission can be stably performed while further cost reduction is realized by reducing the number of capacitance means.

In order to solve the above-mentioned problems, in the invention according to claim 2, in the coil device according to claim 1, the inductance of one of the coils connected to the capacitance means is connected as the threshold value. On the other hand, it is configured to be less than twice the inductance of the coil.

According to the invention of claim 2, in addition to the action of the invention of claim 1, since the inductance of one coil connected to the capacitive means is not more than twice the inductance of the other coil, the magnetic field. Non-contact power transmission by the resonance method can be performed efficiently and stably.

In order to solve the above problems, the invention according to claim 3 has the coil device according to claim 1 or 2, wherein the inductance of one of the coils connected to the capacitive means is used as the threshold value. , 1.5 times or less the inductance of the other connected coil.

According to the invention of claim 3, in addition to the action of the invention of claim 1 or 2, the inductance of one coil connected to the capacitive means is 1.5 times the inductance of the other coil. Since it is as follows, non-contact type power transmission by the magnetic field resonance method can be performed more efficiently and stably.

In order to solve the above problems, the invention according to claim 4 is the center of winding of each of the coils in the winding line in the coil device according to any one of claims 1 to 3. The position coincides in the direction perpendicular to the winding surface of each of the coils, and the number of windings of the winding line in one of the coils connected to the capacitive means is the winding line in the other connected coil. It is configured to be less than twice the number of turns of.

According to the invention of claim 4, in addition to the action of the invention of any one of claims 1 to 3, the position of the center of winding in the winding line of each coil is the position of the center of winding of each coil. Since they match in the direction perpendicular to the winding surface, the number of windings of the winding line in one coil connected to the capacitive means is less than twice the number of windings of the winding line in the other connected coil. , Non-contact power transmission by the magnetic field resonance method can be performed more efficiently and stably.

In order to solve the above problems, the invention according to claim 5 is composed of a power transmission device and a power receiving device separated from the power transmission device, and transmits power from the power transmission device to the power receiving device in a non-contact manner. A power transmission coil including the coil device according to any one of claims 1 to 4, wherein the power transmission device included in the power transmission system is arranged so as to face the power receiving device. And an output means for outputting the electric power to be transmitted to the power transmission coil.

In order to solve the above problems, the invention according to claim 6 is composed of a power transmission device and a power receiving device separated from the power transmission device, and transmits power from the power transmission device to the power receiving device in a non-contact manner. A power receiving coil including the coil device according to any one of claims 1 to 4, wherein the power receiving device included in the power transmission system is arranged so as to face the power transmission device. And an input means connected to the power receiving coil.

In order to solve the above problems, the invention according to claim 7 is the power transmission device according to claim 5 and a power receiving device that is separated from the power transmission device and is arranged so as to face the power transmission coil. A power receiving device for receiving the electric power transmitted from the power transmitting device is provided.

In order to solve the above problems, the invention according to claim 8 is the power transmission device and the power receiving device according to claim 6, which are separated from the power transmission device and the power receiving coil faces the power transmission device. It is provided with a power receiving device for receiving the electric power transmitted from the power transmitting device.

According to the invention according to any one of claims 5 to 8, at least one of the transmission coil provided in the power transmission device constituting the power transmission system and the power receiving coil provided in the power receiving device is claimed. Since the coil device according to any one of claims 1 to 4, the coil device made of a thin film conductor is used when the transmission coil or the power receiving coil is opposed to each other to perform non-contact power transmission. In addition to weight reduction and cost reduction by using it, it is possible to stably perform non-contact power transmission while realizing further cost reduction by reducing the number of capacity means.

According to the present invention, an even number of coils each configured by winding a winding line made of a thin film conductor are laminated, and a capacitive means is connected between two coils laminated adjacent to each other. The difference in inductance between the two coils connected to the capacitive means is set to be less than or equal to the predetermined threshold.

Therefore, by connecting the capacitive means required for the magnetic field resonance method between two coils stacked adjacent to each other and having an inductance difference of less than the predetermined threshold, weight reduction and weight reduction by using a winding line made of a thin film conductor can be achieved. In addition to cost reduction, non-contact power transmission can be stably performed while further cost reduction is realized by reducing the number of capacitance means.

It is a block diagram which shows the outline structure of the power transmission system of an embodiment. It is a circuit diagram or the like which shows the structure of the power transmission device of an embodiment, (a) is the circuit diagram, and (b) is a circuit diagram or the like which shows the structure of the power receiving device of an embodiment. It is a top view (i) which shows the structure of the power receiving coil of an embodiment. It is a top view which shows the structure of the loop coil of an embodiment. It is a top view which shows the structure of the open coil of an embodiment. It is a top view (ii) which shows the structure of the power receiving coil of an embodiment. It is a circuit diagram and the like which show the structure of each of the power transmission device and the power receiving device of the conventional example. It is a circuit diagram or the like which shows the structure of the power receiving device of a modified form.

Next, a mode for carrying out the present invention will be described with reference to the drawings. In the embodiments and modifications described below, the electric power for charging the rechargeable battery mounted on the electric vehicle is transmitted to the electric vehicle equipped with the rechargeable battery in a non-contact manner by a magnetic field resonance method. It is an embodiment and a modification when this invention is applied to a power transmission system.

Here, the electric power transmission system by the magnetic field resonance method of the embodiment and the modified form is arranged so as to be separated from the power transmission coil and face each other (that is, facing each other) and is sent from the power transmission coil. It is equipped with a power receiving coil that receives the generated power. The power transmission coil is composed of a power transmission loop coil, which will be described later, and a power transmission open coil, which will be described later, laminated. Further, the power receiving coil is configured by laminating a power receiving open coil described later and a power receiving loop coil described later. Further, the transmission loop coil and the transmission open coil, and the above-mentioned power receiving open coil and the above power receiving loop coil are each a resonance capacitor (that is, a series resonance capacitor or a parallel resonance capacitor) described later used in the magnetic field resonance method. Is connected.

[Embodiment]
First, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

(I) Overall configuration and operation of the power transmission system of the embodiment
First, the overall configuration and operation of the power transmission system of the embodiment will be described with reference to FIG. Note that FIG. 1 is a block diagram showing an outline configuration of the power transmission system of the embodiment.

As shown in FIG. 1, the power transmission system S of the embodiment includes a power transmission device T including a power transmission unit TR and the power transmission coil TC, and a power reception device R including a power reception unit RV and the power reception coil RC. Has been done. At this time, the power receiving device R is mounted on the electric vehicle and is connected to a storage battery (not shown) mounted on the electric vehicle. On the other hand, the power transmission device T is installed on the ground where the electric vehicle moves or stops. Then, when charging the storage battery, the electric vehicle is operated or stopped so that the power receiving coil RC of the power receiving device R and the power transmission coil TC of the power transmission device T face each other. When charging the storage battery by the power transmission system S of the embodiment, the power transmission device T installed on the ground below the stop position of the power receiving device R mounted on the stopped electric vehicle is used. It can be configured to transmit electric power from the power transmission device T via the power transmission coil TC. In addition, for the power receiving device R mounted on the moving electric vehicle, via the power transmission coil TC of a plurality of power transmission devices T installed in a certain distance section of the road on which the electric vehicle is moving. Therefore, it may be configured to continuously transmit electric power from the power transmission device T. At this time, the power transmission unit TR corresponds to an example of the "output means" of the present invention, and the power receiving unit RV corresponds to an example of the "input means" of the present invention. Further, each of the power transmission coil TC and the power reception coil RC corresponds to an example of the "coil device" of the present invention.

On the other hand, the power transmission coil TC includes a power transmission loop coil TL and a power transmission open coil TO. Further, the power receiving coil RC includes a power receiving open coil RO and a power receiving loop coil RL. In the above configuration, each of the power transmission loop coil TL and the power reception loop coil RL corresponds to an example of the "coil" of the present invention. The power to be transmitted is input from the power transmission unit TR to one of the external connection terminals of the power transmission loop coil TL, and the above-mentioned resonance capacitor is connected to the other of the external connection terminals in the manner described later. The power transmission open coil TO is concentrically laminated with respect to the power transmission loop coil TL, and other resonance capacitors are connected to both ends thereof in a manner described later. On the other hand, the power receiving open coil RO is arranged so as to face the power transmission open coil TO, and one of the above-mentioned resonance capacitors is connected to both ends thereof in a manner described later. The power receiving loop coil RL is concentrically laminated with respect to the power receiving open coil RO, one of the external connection terminals is connected to the power receiving unit RV, and the other of the external connection terminals is the other in the manner described later. The above resonance capacitor is connected. Then, the power receiving loop coil RL outputs the power received from the power transmission coil TC to the power receiving unit RV via the power receiving open coil RO by the magnetic field resonance method. At this time, the power transmission open coil TO is an open coil for reducing the impedance (loss due to Joule heat; the same applies hereinafter) by reducing the current flowing through the power transmission loop coil TL. Further, the power receiving open coil RO is an open coil for reducing the impedance by reducing the current flowing through the power receiving loop coil RL during power transmission using the power transmission system S.

In the above configuration, the power transmission unit TR of the power transmission device T outputs the power to be transmitted to the power reception device R to the power transmission coil TC while complying with the regulations such as the Radio Law in the country where the power transmission system S is used. .. At this time, the above-mentioned regulations and the like regulate the leakage magnetic field so as to be below a predetermined level in consideration of the influence on the human body, for example. Further, in order to be able to use the interconnection between all the power transmission devices T and the power receiving device R, as a result, it is necessary for both to use a frequency within a predetermined range, which is why. The frequency or frequency band in the predetermined range must follow the recommendations of international organizations such as ISO (International Organization for Standardization) or IEC (International Electrotechnical Commission) as the above-mentioned regulations. Further, since the lower limit value of the transmission efficiency in consideration of the predetermined positional deviation between the power transmission coil TC and the power reception coil RC is also defined by the above-mentioned international organization, high transmission efficiency is required for the power transmission system S as well.

On the other hand, the power receiving coil RC of the power receiving device R that has received the power from the power transmission coil TC by the magnetic field resonance method outputs the received power to the power receiving unit RV. As a result, the power receiving unit RV converts the output corresponding to the electric power (for example, the high frequency power of 85 kilohertz) into a DC (direct current) current by a power conversion unit (not shown) and outputs the output to the storage battery of the electric vehicle. .. As a result, the storage battery is charged with a required amount of electric power.

(II) Configuration of power receiving coil RC (power transmission coil TC)
Next, the configurations of the power receiving coil RC and the power transmission coil TC of the embodiment used in the power transmission system S of the above-described embodiment will be described with reference to FIGS. 2 to 6. Note that FIG. 2 is a circuit diagram or the like showing the configuration of the power transmission device T of the embodiment, and FIGS. 3 and 6 are plan views showing the structure of the power receiving coil RC of the embodiment. Further, FIG. 4 is a plan view showing the structure of the loop coil of the embodiment, and FIG. 5 is a plan view showing the structure of the open coil of the embodiment. 3 to 6 are plan views of the power receiving device R when the power receiving coil RC is viewed from the power receiving unit RV side.

First, a specific configuration of the power transmission device T including the power transmission coil TC will be described with reference to the circuit diagram and the like shown in FIG. 2A. As shown as a circuit diagram in FIG. 2A, the power transmission coil TCs are each composed of wound copper thin film wires and laminated so that the centers of the wounds coincide with each other via an insulating film described later. It is provided with two power transmission loop coils TL1 and power transmission loop coil TL2. In these power transmission loop coil TL1 and power transmission loop coil TL2, when the power transmission coil TC is located at a position facing the power reception coil RC, the winding surfaces of the power transmission loop coil TL1 and the power transmission loop coil TL2 are perpendicular to the direction of the power transmission coil RC as seen from the power transmission coil TC. The copper thin film wire is wound so as to be. One terminal of the power transmission loop coil TL1 and the power transmission loop coil TL2 is connected to the power transmission unit TR as described above, and the other terminal of the power transmission loop coil TL1 and the power transmission loop coil TL2 is connected in series as described above. The capacitor CT1 is connected.

Further, as described above, the power transmission open coil TO is concentrically laminated on the power transmission loop coil TL1 and the power transmission loop coil TL2 via an insulating film. The series resonance capacitor CT2 described above is connected to both ends of the power transmission open coil TO. The specific configurations (shape, etc.) of the power transmission loop coil TL1, the power transmission loop coil TL2, and the power transmission open coil TO are as the configurations (shape, etc.) of the power receiving loop coil RL and the power receiving open coil RO having the same configuration. Will be described in detail later with reference to FIGS. 3 to 6.

Here, the relationship between the number of turns of the copper thin film wire in the power transmission loop coil TL1 and the number of turns of the copper thin film wire in the power transmission loop coil TL2 is that one is twice or less, preferably one and a half times or less. Is preferable. Further, the relationship between the inductance of the power transmission loop coil TL1 and the inductance of the power transmission loop coil TL2 is preferably not more than twice, preferably not more than one and a half times that of the other.

Next, a specific configuration of the power receiving device R including the power receiving coil RC will be described with reference to the circuit diagram and the like shown in FIG. 2 (b). As shown as a circuit diagram in FIG. 2B, the power receiving coils RC are each composed of wound copper thin film wires, and are laminated so that the centers of the windings coincide with each other via an insulating film described later. It is provided with two power receiving loop coils RL1 and a power receiving loop coil RL2. In these power receiving loop coil RL1 and power receiving loop coil RL2, when the power receiving coil RC is located at a position facing the power transmission coil TC, the winding surfaces of the power receiving loop coil RL1 and the power receiving loop coil RL2 are perpendicular to the direction of the power transmission coil TC as seen from the power receiving coil RC. The copper thin film wire is wound so as to be. The external connection terminal O1 and the external connection terminal O2 of the power receiving loop coil RL1 and the power receiving loop coil RL2 are connected to the power receiving unit RV as described above, and the connection terminal TR1 and the power receiving loop coil RL2 of the power receiving loop coil RL1 are connected. As described above, the series resonance capacitor CR1 is connected to the terminal TR2.

Further, as described above, the power receiving open coil RO is concentrically laminated on the power receiving loop coil RL1 and the power receiving loop coil RL2 via an insulating film. Both ends of the power receiving open coil RO are a connection terminal T1 and a connection terminal T2 to which the above-mentioned series resonance capacitor CR2 is connected.

Here, the relationship between the number of windings of the copper thin film wire in the power receiving loop coil RL1 and the number of windings of the copper thin film wire in the power receiving loop coil RL2 is that one is twice or less, preferably one and a half times or less. Is preferable. Further, the relationship between the inductance of the power receiving loop coil RL1 and the inductance of the power receiving loop coil RL2 is preferably not more than twice, preferably not more than one and a half times that of the other.

Next, the specific configurations (shape, etc.) of the power transmission loop coil TL1, the power transmission loop coil TL2, and the power transmission open coil TO, and the specific configurations of the power reception loop coil RL1, the power reception loop coil RL2, and the power reception open coil RO (the shape, etc.) The shape and the like) will be described with reference to FIGS. 3 to 6. The configuration of the power transmission loop coil TL1 and the configuration of the power reception loop coil RL1 are the same except for their own sizes. Further, the configuration of the power transmission loop coil TL2 and the configuration of the power reception loop coil RL2 are the same except for the number of turns thereof and the size of each of them. Further, the configuration of the power transmission open coil TO and the configuration of the power reception open coil RO are the same except for the number of turns thereof and the size of each of them. Furthermore, the positional relationship between the power transmission loop coil TL1 and the power transmission loop coil TL2 and the power transmission open coil TO in the power transmission coil TC, and the position of the power reception loop coil RL1 and the power reception loop coil RL2 and the power reception open coil RO in the power reception coil RC. The relationship is the same. Therefore, in the following description, the configurations (shapes, etc.) of the power receiving loop coil RL1, the power receiving loop coil RL2, and the power receiving open coil RO will be described.

As shown in the plan view of FIG. 3, the power receiving coil RC of the embodiment includes a power receiving loop coil RL1 composed of two parallel parallel copper thin film wires RL11 and a copper thin film wire RL12, which will be described later, and FIG. A power receiving loop coil RL2 (not shown) is laminated in a direction perpendicular to the paper surface of FIG. 3 via the insulating film BF (details will be described later). Further, in the power receiving coil RC, the power receiving open coil RO (not shown in FIG. 3) is further laminated directly under the power receiving loop coil RL2 via an insulating film (not shown in FIG. 3) in the direction perpendicular to the paper surface of FIG. Has been done. In this configuration, the copper thin film wire TL11 and the copper thin film wire TL12 correspond to an example of the "winding line" of the present invention. In the embodiment, a film BF is used for insulation between the power receiving loop coil RL1 and the power receiving loop coil RL2, and a similar film is used for insulation between the power receiving loop coil RL2 and the power receiving open coil RO. However, in addition to these, an insulating material such as a glass epoxy material can also be used. Further, in order to efficiently dissipate the heat generated as the power receiving coil RC, for example, a thin film material in which ceramic particles or the like are dispersed can be used. Further, an appropriate void holding material may be used so as to be laminated through the required voids. Furthermore, the center of winding of the copper thin film wire RL11 and the copper thin film wire RL12 constituting the power receiving loop coil RL1 and the winding center of the copper thin film wire described later constituting the power receiving loop coil RL2 and the power receiving open coil RO, respectively. Are the same or substantially the same as each other.

As shown in FIG. 3, the power receiving loop coil RL1 is composed of a copper thin film wire RL11 and a copper thin film wire RL12 wound in parallel with each other in the same layer of the power receiving coil RC, and the outermost peripheral portion thereof. An external connection terminal O1 (see FIG. 2B) that connects one end of the copper thin film wire RL11 and one end of the copper thin film wire RL12 to one side and is connected to the power receiving unit RV, and the other end of the copper thin film wire RL11. It has a connection terminal TR1 (see FIG. 2B) to which the other end of the copper thin film wire RL12 is connected and one end of the series resonance capacitor CR1 is connected. The power receiving loop coil RL1 is configured by winding the copper thin film wire RL11 and the copper thin film wire RL12 three times (3 turns) in parallel, and both ends of each of the copper thin film wire RL11 and the copper thin film wire RL12 (FIG. In the case shown in 3, the center of the right side portion) is connected to the external connection terminal O1 and the connection terminal TR1. The copper thin film wire RL11 and the copper thin film wire RL12 each have the same width and the same thickness over the entire circumference of the power receiving loop coil RL1. Further, the intersecting portions of the copper thin film wire RL11 and the copper thin film wire RL12 in the power receiving loop coil RL1 (two locations shown by a broken line in FIG. 3) are connected by an interlayer connection via an insulating layer or a connection using a jumper wire. The copper thin film wire RL11 and the copper thin film wire RL12 are crossed while maintaining the insulating property at the intersecting portion. Further, in each of the copper thin film wire RL11 and the copper thin film wire RL12, a straight line portion is provided on each of the upper side portion, the lower side portion, the left side portion and the right side portion in FIG. 3, and each straight line portion is connected by a curved portion. There is.

Next, the configuration of the power receiving loop coil RL2 laminated directly under the power receiving loop coil RL1 via the film BF will be described with reference to FIG. Note that FIG. 4 is a plan view showing only the power receiving loop coil RL2 taken out.

As shown in FIG. 4, the power receiving loop coil RL2 is composed of a copper thin film wire RL21 and a copper thin film wire RL22 wound in parallel with each other in the same layer of the power receiving coil RC, and the outermost peripheral portion thereof. A connection terminal TR2 (see FIG. 2B) to which one end of the copper thin film wire RL21 and one end of the copper thin film wire RL22 are connected to one side and the other end of the series resonance capacitor CR1 is connected, and the copper thin film wire. It has an external connection terminal O2 (see FIG. 2B) that connects the other end of the RL 21 and the other end of the copper thin film wire RL22 and is connected to the power receiving unit RV. The power receiving loop coil RL2 is configured by winding the copper thin film wire RL21 and the copper thin film wire RL22 twice (two turns) in parallel, and both ends of each of the copper thin film wire RL21 and the copper thin film wire RL22 (FIG. In the case shown in 4, the center of the right side portion) is connected to the external connection terminal O2 and the connection terminal TR2. The copper thin film wire RL21 and the copper thin film wire RL22 each have the same width and the same thickness over the entire circumference of the power receiving loop coil RL2. Further, at the intersection of the copper thin film wire RL21 and the copper thin film wire RL22 in the power receiving loop coil RL2 (one place shown by a broken line in FIG. 4), an interlayer connection via an insulating layer or a connection using a jumper wire is used. The copper thin film wire RL21 and the copper thin film wire RL22 are crossed while maintaining the insulating property at the intersecting portion.
Further, in each of the copper thin film wire RL21 and the copper thin film wire RL22, a straight line portion is provided on each of the upper side portion, the lower side portion, the left side portion and the right side portion in FIG. 4, and each straight line portion is connected by a curved portion. There is.

Next, the configuration of the power receiving open coil RO laminated directly under the power receiving loop coil RL2 via a film (not shown) will be described with reference to FIG. Note that FIG. 5 is a plan view showing only the power receiving open coil RO taken out.

As shown in FIG. 5, the power receiving open coil RO is composed of a copper thin film wire ROL wound in parallel with each other in the same layer of the power receiving coil RC, and the outermost peripheral portion of the copper thin film wire ROL. And each of the innermost peripheral portion is a connection terminal T1 and a connection terminal T2 (see FIG. 2B) connected to the series resonance capacitor CR2. The power receiving open coil RO is configured by winding a copper thin film wire ROL 12 times (12 turns). The copper thin film wire ROL has the same width and the same thickness over the entire circumference of the power receiving open coil RO. Further, in the copper thin film wire ROL, a straight line portion is provided on each of the upper side portion, the lower side portion, the left side portion, and the right side portion in FIG. 5, and each straight line portion is connected by a curved portion.

Next, the power receiving loop coil RL1 (that is, the copper thin film wire RL11 and the copper thin film wire RL12), the power receiving loop coil RL2 (that is, the copper thin film wire RL21 and the copper thin film wire RL22), and the power receiving open coil RO (that is, the copper thin film wire ROLL) The positional relationship will be described with reference to FIG. FIG. 6 is a plan view showing the overlapping state of the power receiving loop coil RL1, the power receiving loop coil RL2, and the power receiving open coil RO, and the power receiving loop coil RL1 (copper thin film wire RL11 and copper thin film wire RL12) is shown by a solid line. The power receiving loop coil RL2 (copper thin film wire RL21 and copper thin film wire RL22) laminated directly under the film BF (not shown in FIG. 6) is shown by a broken line, and the film (copper thin film wire RL21 and copper thin film wire RL22) is directly below the power receiving loop coil RL2. The power receiving open coil RO (copper thin film wire ROLL) further laminated via (not shown in FIG. 6) is shown by a single point chain wire.

As shown by the solid wire in FIG. 6, the copper thin film wire RL11 and the copper thin film wire RL12 are wound one and a half turns (1.5 turns) counterclockwise from the outer circumference to the inner circumference from the external connection terminal O1. In the power receiving loop coil RL1 which is wound one and a half turns (1.5 turns) from the inner circumference to the outer circumference and connected to the connection terminal TR1, the copper thin film wire RL11 and the copper thin film wire RL12 are wound every one round. The position of the straight portion is inward by one pitch in one turn (that is, the radial distance in winding between the centers between the copper thin film wire RL11 and the copper thin film wire RL12 on each side. The same applies hereinafter). Each curved portion is formed so as to be displaced toward the peripheral side or the outer peripheral side, and the copper thin film wire RL11 and the copper thin film wire RL12 are wound. On the other hand, as shown by the broken line in FIG. 6, the copper thin film wire RL21 and the copper thin film wire RL22 are wound counterclockwise from the connection terminal TR2 from the outer circumference to the inner circumference by one rotation (1 turn), and then the inner circumference. In the power receiving loop coil RL2, which is wound one turn (one turn) from the outer circumference and connected to the external connection terminal O2, one pitch in the winding of the copper thin film wire RL21 and the copper thin film wire RL22 for each round. Each curved portion is formed so that the position of the straight portion is shifted to the inner peripheral side or the outer peripheral side by the amount, and the copper thin film wire RL21 and the copper thin film wire RL22 are wound. Then, as shown in FIG. 6, a series resonance capacitor CR1 is connected to the connection terminal TR1 and the connection terminal TR2.

Next, as shown by the alternate long and short dash line in FIG. 6, the copper thin film wire ROL is wound 12 turns (12 turns) counterclockwise from the outer circumference to the inner circumference from the connection terminal T1, and the innermost circumference thereof is wound. In the power receiving open coil RO, which is the connection terminal T2, each curved portion is formed so that the position of the straight portion is shifted toward the inner circumference by one pitch in the winding of the copper thin film wire ROL. The copper thin film wire ROL is wound around. Then, as shown in FIG. 5, a series resonance capacitor CR2 is connected to the connection terminal T1 and the connection terminal T2.

In manufacturing the power receiving coil RC and the power transmitting coil TC (including each series resonance capacitor) of the embodiment, basically the same manufacturing method as in the conventional method using the so-called photolithography technique can be used.

Next, regarding the effect of power transmission using the power transmission system S of the embodiment including the power receiving coil RC and the power transmission coil TC of the embodiment, the experimental results by the inventor of the present application (simulation results; the same applies hereinafter). ), This will be described with reference to FIG. 7. In the following description, the simulation result of the effect when the power transmission is performed using the power transmission system S of the embodiment is performed by using the power transmission system including the power transmission device and the power reception device of the conventional example. This will be explained while comparing it with the simulation result of the effect of the case. Further, FIG. 7 is a circuit diagram or the like showing the configuration of a power transmission system including the power transmission device and the power reception device of the above-mentioned conventional example.

At this time, as shown in FIG. 7, the power transmission system SX of the conventional example is a transmission loop coil TLX connected to the transmission unit TR similar to the transmission device T of the embodiment via the series resonance capacitor CTX1 and the series resonance capacitor CTX2. A power receiving device including a power receiving loop coil RLX connected to a power receiving unit RV similar to the power receiving device R of the embodiment via a series resonance capacitor CRX1 and a series resonance capacitor CRX2 and a parallel resonance capacitor CRX3. It is composed of RX and. Then, as an experiment of the example, the inventor of the present application performed power transmission using the power transmission system S and the power transmission system SX having the following specifications, and calculated the transmission efficiency of each.

(1) Specifications of power receiving coil RC and power transmission coil TC for which experimental results are shown as examples.
-Overall shape of power transmission coil TC: 570 mm x 470 mm square-Overall shape of power receiving coil RC: 320 mm x 320 mm square-Number of turns of power transmission loop coil TL1: 4
-Number of turns of the power receiving loop coil RL1: 3 (see FIG. 3)
-Number of turns of each of the power transmission loop coil TL2 and the power reception loop coil RL2: 2 (see FIG. 4).
・ Number of turns of power transmission open coil TO: 13
-Number of turns of the power receiving open coil RO: 12 (see Fig. 5)
-Inductance of power transmission loop coil TL1: 13.9 microhenry (μH)
・ Intensity of power receiving loop coil RL1: 2.5 microhenry ・ Inductivity of power transmission loop coil TL2: 4.5 microhenry ・ Intensity of power receiving loop coil RL2: 4.2 microhenry ・ Transmission loop coil TL1 and power transmission loop coil TL2 Combined inductance: 33.7 microhenry, combined inductance of power receiving loop coil RL1 and power receiving loop coil RL2: 11.8 microhenry, inductance of transmission open coil TO: 147.5 microhenry, inductance of power receiving open coil RO: 67.8 Micro Henry ・ Line width of copper thin film wire RL11 etc. in each of power transmission loop coil TL1 and power transmission loop coil TL2 and power receiving loop coil RL1 and power receiving loop coil RL2: all 8 mm ・ power transmission open coil TO and power receiving open coil RO respectively Wire width of copper thin film wire ROLL, etc .: 8 mm in both-Transmission loop coil TL1 and transmission loop coil TL2, and power receiving loop coil RL1 and power receiving loop coil RL2, respectively, in one winding, adjacent copper thin film wires (for example, Spacing between copper thin film wire RL11 and copper thin film wire RL12): all 4 mm ・ Pitch in transmission loop coil TL1 and power receiving loop coil RL1: both 18 mm ・ Pitch in transmission loop coil TL2 and power receiving loop coil RL2: both 10 mm ・ Transmission Pitch in open coil TO and power receiving open coil RO: both 10 mm ・ Thickness of each copper thin film wire RL11 etc. in power receiving loop coil RL1 etc .: 0.2 mm in all ・ Capacity of series resonance capacitor CT1: 84 nanofarad ( nF)
・ Capacitance of series resonance capacitor CR1: 330 nanofarad ・ Capacitance of series resonance capacitor CT2: 5 nanofarad ・ Capacitance of series resonance capacitor CR2: 15 nanofarad

(2) Specifications of power receiving coil RC and power transmission coil TC for which experimental results are shown as conventional examples.
The structure of the power transmission coil and the structure of the power receiving coil as a conventional example are basically the same as the structure of the power transmission coil TC and the structure of the power receiving coil RC of the embodiment except for the part of the resonance capacitor.
-Overall shape of power transmission loop coil TLX: 570 mm x 470 mm square-Overall shape of power receiving loop coil RLX: 320 mm x 320 mm square-Number of turns of power transmission loop coil TLX: 4
-Number of turns of the power receiving loop coil RLX: 3
・ Induction of transmission loop coil TLX: 33.7 microhenry ・ Intensity of power receiving loop coil RLX: 11.8 microhenry ・ Line width of copper thin film wire in each of transmission loop coil TLX and power receiving loop coil RLX: all 8 mm ・ Transmission Pitch in loop coil TLX and power receiving loop coil RLX: 18 mm in both cases ・ Thickness of each copper thin film wire in transmission loop coil TLX and power receiving loop coil RLX: all 0.2 mm ・ Static series resonance capacitor CTX1 and series resonance capacitor CTX2 Capacitance: 168 nanofarads ・ Capacitance of series resonance capacitor CRX1 and series resonance capacitor CRX2: 660 nanofarads

Then, as shown in Table 1 below, when the power transmission system S of the embodiment is used, the number is halved and the capacitance is also halved as compared with the case of using the power transmission system SX of the conventional example. The same transmission efficiency can be obtained by using the series resonance capacitor CT1 and the series resonance capacitor CR1.

As described above, according to the power transmission using the power transmission system S of the embodiment including the power receiving coil RC and the power transmission coil TC of the embodiment, each of them is configured by winding the copper thin film wire RL11 or the like. One power receiving loop coil RL1 and a power receiving loop coil RL2 (transmission loop coil TL1 and power transmission loop coil TL2) are laminated, and between the power receiving loop coil RL1 and the power receiving loop coil RL2 laminated adjacent to each other (transmission loop coil). A series resonance capacitor CR1 (series resonance capacitor CT1) is connected between the TL1 and the transmission loop coil TL2), and the power receiving loop coil RL1 and the power receiving loop coil connected to the series resonance capacitor CR1 (series resonance capacitor CT1). The difference in inductance between the RL2 (between the transmission loop coil TL1 and the transmission loop coil TL2) is not more than twice that of the other, preferably not more than one and a half times. Therefore, the series resonance capacitors required for the magnetic field resonance method are stacked adjacent to each other and the inductance difference is equal to or less than the predetermined threshold value between the power receiving loop coil RL1 and the power receiving loop coil RL2 (the transmission loop coil TL1 and the transmission loop coil TL2). By connecting to (between), in addition to weight reduction and cost reduction by using copper thin film wire RL11 etc., further cost reduction by reducing the number of series resonant capacitors is realized, and non-contact type power supply is realized. The transmission can be performed stably.

Further, when the difference in inductance is one and a half or less, non-contact power transmission by the magnetic field resonance method can be performed more efficiently and stably.

Furthermore, the positions of the winding centers of the power receiving loop coil RL1 and the power receiving loop coil RL2 (power transmission loop coil TL1 and power transmission loop coil TL2) coincide with each other in the direction perpendicular to each winding surface (see FIG. 6). Moreover, since one of the above inductance differences is less than twice that of the other, non-contact power transmission by the magnetic field resonance method can be performed more efficiently and stably.

[Transformation]
Next, a modified form of the present invention will be described with reference to FIG. Note that FIG. 8 is a circuit diagram or the like showing the configuration of the power receiving device in the modified form. Further, in FIG. 8, the same members as those of the power receiving device R of the embodiment are designated by the same member numbers, and detailed description thereof will be omitted.

As the modified form of the power receiving device RM, a power receiving coil RMC provided with the parallel resonance capacitor CP shown in FIG. 7 is used instead of the power receiving open coil RO and the series resonance capacitor CR2 of the power receiving device R in the power transmission system S of the above-described embodiment. You may use it. As the modified power transmission device, it is preferable to use a power transmission device having the same configuration as that of the power transmission device T of the embodiment. Even if the modified power receiving device RM having the above configuration is used, the same effect as that of the power transmission system S of the embodiment using the power receiving device R of the embodiment can be obtained.

Further, as another modification, the power transmission coil TC of the embodiment includes a power transmission loop coil TL1 and a power transmission loop coil TL2 (that is, a two-layer power transmission loop coil), and the power receiving coil RC of the embodiment has a power receiving loop coil RL1 and a power receiving loop. The coil RL2 (that is, a two-layer power transmission loop coil) was provided, but in addition to these, the power transmission coil has four or more layers and an even number of power transmission loop coils, and the power receiving coil has four or more layers and an even number of power receiving loop coils. It is also possible to apply the present invention in some cases. In this case, if a series resonance capacitor corresponding to the series resonance capacitor CR1 or the like of the embodiment is connected between two layers of loop coils (power transmission loop coil or power reception loop coil) stacked adjacent to each other. good.

As described above, the present invention can be used in the field of non-contact power transmission, and is particularly remarkable when applied in the field of power transmission for charging a storage battery mounted on an electric vehicle. The effect is obtained.

S, SX Power transmission system T Transmission device R, RM Power receiving device TR Transmission unit TC Transmission coil RV Power receiving unit RC, RMC Power receiving coil TL, TL1, TL2 Transmission loop coil TO Transmission open coil RO Power receiving open coil RL, RL1, RL2 Loop coil CT1, CT2, CR1, CR2 Series resonance capacitor CP, CRX3 Parallel resonance capacitor O1, O2 External connection terminal TR1, TR2, T1, T2 Connection terminal RL11, RL12, RL21, RL22, ROLL Copper thin film wire BF film

Claims (8)

In a coil device for non-contact power transmission by the magnetic field resonance method
An even number of coils, each of which is configured by winding a winding line made of a thin film conductor, and a coil laminated with an insulating layer sandwiched between them.
Capacitive means for resonance connected between the two coils stacked adjacent to each other, and
Equipped with
A coil device, characterized in that the difference in inductance between the two coils connected to the capacitive means is equal to or less than a preset threshold value. In the coil device according to claim 1,
As the threshold value, the coil device is characterized in that the inductance of one of the coils connected to the capacitance means is not more than twice the inductance of the other connected coil. In the coil device according to claim 1 or 2.
As the threshold value, the coil device is characterized in that the inductance of one of the coils connected to the capacitance means is 1.5 times or less the inductance of the other connected coil. The coil device according to any one of claims 1 to 3.
The position of the center of winding of each coil in the winding line coincides with the direction perpendicular to the winding surface of each coil.
A coil device characterized in that the number of windings of a winding line in one of the coils connected to the capacitive means is twice or less the number of windings of a winding line in the other connected coil. In the power transmission device included in the power transmission system, which is composed of a power transmission device and a power reception device separated from the power transmission device, and transmits power from the power transmission device to the power reception device in a non-contact manner.
A power transmission coil including the coil device according to any one of claims 1 to 4, wherein the power transmission coil is arranged so as to face the power receiving device.
An output means that outputs the power to be transmitted to the power transmission coil,
A power transmission device characterized by being equipped with. In the power receiving device included in the power transmission system, which is composed of a power transmitting device and a power receiving device separated from the power transmitting device, and transmits power from the power transmitting device to the power receiving device in a non-contact manner.
A power receiving coil including the coil device according to any one of claims 1 to 4, wherein the power receiving coil is arranged so as to face the power transmission device.
The input means connected to the power receiving coil and
A power receiving device characterized by being provided with. The power transmission device according to claim 5 and
A power receiving device that is separated from the power transmission device and is arranged so as to face the power transmission coil and that receives power transmitted from the power transmission device.
A non-contact power transmission system characterized by being equipped with. Power transmission equipment and
The power receiving device according to claim 6, wherein the power receiving coil is arranged so as to be separated from the power transmission device and the power receiving coil is opposed to the power transmission device, and receives power transmitted from the power transmission device.
A non-contact power transmission system characterized by being equipped with.

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