Cavity resonance power transmission device and wireless power transmission system

Abstract

A cavity resonance power transmission device 100 comprises: a structure 10 which is entirely surrounded by an electromagnetic wave shielding member having conductivity; a power transmitter 20 which wirelessly supplies power to a product 31 via a power receiver 30 disposed in the internal space of the structure 10; and a partition body 40 which separates the power receiver 30 and the power transmitter 20. The structure 10 has a bottom portion 11, a top portion 12 facing the bottom portion 11, and a side portion 13 connecting the outer edges of the bottom portion 11 and the top portion 12. The power transmitter 20 is provided in contact with an inner surface of the bottom portion 11.

Description

Cavity resonance type power transmission device and wireless power transmission system

[0001] The present invention relates to a cavity resonance type power transmitter and a wireless power transmission system, and more particularly to a cavity resonance type power transmitter and a wireless power transmission system for efficiently transmitting wireless power.

[0002] Many electronic devices these days are equipped with secondary batteries that allow for repeated charging. These products are manufactured by manufacturers, then packaged, shipped, and displayed in retail stores such as mass retailers.

[0003] The secondary batteries installed in electronic devices thus displayed gradually lose battery power due to dark current. If they reach an over-discharge state, discharging beyond the safe discharge range, this can cause deterioration or damage to the secondary batteries.

[0004] To avoid over-discharge, shipped electronic devices must be charged after a certain period of time. However, electronic devices displayed in stores are generally packaged in some form, so in order to return the electronic device to a charged state, the package must be opened, the electronic device removed, charged, and then repackaged after charging is complete.

[0005] Unpacking, charging, and then repacking the device is costly. However, if the device could be charged while still in its packaging, costs could be reduced. The number of electronic devices collected from mass retailers for charging varies depending on the volume of products in circulation. Therefore, it is sometimes desirable to be able to charge a large number of products uniformly at once.

[0006] Patent Document 1 discloses a method for extracting energy from a solar cell module by using impedance, the method including the steps of generating an oscillating magnetic field by supplying energy to at least one wireless energy supply source using electrical energy from the solar cell module and configuring the supply source to present an impedance to the solar cell module. By utilizing the wireless power supply disclosed in Patent Document 1, batteries can be charged without unpacking multiple products. However, the method disclosed in Patent Document 1 has a problem in that the amount of charge that can be charged by the power receiver decreases as the distance from the power transmitter increases.

[0007] In response to this, Patent Document 2 discloses a method for efficiently supplying power even at a location far from the power transmitter by exciting a resonant mode within the entire space surrounded by a conductor and utilizing this.

[0008] Special Publication No. 2015-502726 Publication Patent No. 7307933

[0009] However, in Patent Document 2, the power transmitter is placed on the top of the housing, so it can only support wireless power supply of small amounts of energy. In order to transmit power to a large number of products as in Patent Document 1, the power transmitter must be bloated, which reduces the stability of the housing.

[0010] To solve this problem, it has been considered to place the power transmitter on the bottom of the housing, but it has been discovered that in a device with a power transmitter on the bottom of the housing, when the power receiver is stacked, it is difficult to sufficiently charge the power receiver placed on the bottom side of the housing. This is a new problem discovered by the inventors.

[0011] The present invention has been made to solve the above-mentioned problems, and aims to provide an apparatus and system that can transmit power to multiple receivers simultaneously and supply power evenly without attenuation with distance from the transmitter.

[0012] The cavity resonant type power transmitter of the present invention comprises a structure entirely surrounded by a conductive electromagnetic wave shielding member, a power transmitter that wirelessly supplies power to a product via a power receiver placed in the internal space of the structure, and a partition that separates the power receiver and the power transmitter, wherein the structure has a bottom, a top opposite to the bottom, and a side that connects the outer edges of the bottom and the top, and the power transmitter is provided in contact with the inner surface of the bottom.

[0013] The wireless power transmission system of the present invention comprises a cavity resonance type power transmitter of the present invention and a power receiver arranged in the internal space of a structure of the cavity resonance type power transmitter, and is configured to wirelessly supply power to a product from the power transmitter via the power receiver.

[0014] According to the present invention, it is possible to provide a device and a system that can transmit power to a plurality of power receivers simultaneously and supply power evenly without attenuation depending on the distance from the power transmitter.

[0015] FIG. 1 is a schematic perspective view showing an example of a wireless power transmission system according to a first embodiment of the present invention. FIG. 2 is a schematic view of an example of a power transmitter according to the present invention. FIG. 3 is a schematic view of an example of a power receiver according to the present invention. FIG. 4 is a schematic view of an example of a power receiver and a product according to the present invention. FIG. 5 is a schematic view showing an example of an electric field intensity distribution in TE mode in the internal space of a cavity resonance type power transmitter. FIG. 6 is a schematic perspective view showing an example of a wireless power transmission system according to a second embodiment of the present invention. FIG. 7 is a schematic perspective view showing an example of a wireless power transmission system according to a third embodiment of the present invention. FIG. 8 is a schematic cross-sectional view showing an example of a wireless power transmission system according to a fourth embodiment of the present invention. FIG. 9 is a schematic cross-sectional view showing another example of a wireless power transmission system according to the fourth embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing another example of a wireless power transmission system according to the present invention.

[0016] The following describes a cavity resonance type power transmitter and a wireless power transmission system according to the present invention. However, the present invention is not limited to the following embodiments and can be modified as appropriate within the scope of the present invention. Note that a combination of two or more of the individual preferred configurations of the present invention described below also constitutes the present invention.

[0017] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. From the second embodiment onwards, a description of the matters common to the first embodiment will be omitted, and only the differences will be described. In particular, similar effects due to similar configurations will not be mentioned in each embodiment.

[0018] In the following description, when there is no need to particularly distinguish between the embodiments, they will simply be referred to as "the cavity resonance type power transmitting device of the present invention" and "the wireless power transmission system of the present invention."

[0019] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, and other scales may differ from those of the actual product. The same or equivalent parts in the drawings will be designated by the same reference numerals. Furthermore, the same elements in each drawing will be designated by the same reference numerals, and redundant explanations will be omitted.

[0020] In this specification, terms indicating the relationship between elements (e.g., "perpendicular," "parallel," "orthogonal," etc.) and terms indicating the shapes of elements are not expressions that only express a strict meaning, but are expressions that mean that a range of substantial equivalence, for example, a difference of about several percent, is also included. Furthermore, in this specification, "constant" is not an expression that means only when something is completely constant, but is an expression that means when something is substantially constant, for example, a difference of about several percent.

[0021] In this specification, the width direction, length direction, and height direction are defined as directions defined by X, Y, and Z, respectively, as shown in FIG. 1 and the like. The width direction X, length direction Y, and height direction Z are perpendicular to one another. Furthermore, a direction perpendicular to the height direction Z and including the width direction X and length direction Y is defined as a planar direction (XY plane direction). In this specification, it is preferable that the height direction Z is the vertical direction. In this case, the XY plane is a horizontal plane.

[0022] A first embodiment of a wireless power transmission system according to the present invention will be described below with reference to Fig. 1. Fig. 1 is a schematic perspective view showing an example of a wireless power transmission system according to the first embodiment of the present invention. In Fig. 1, a wireless power transmission system 500 includes a cavity resonance type power transmitter 100 and a power receiver 30 disposed in an internal space of a structure 10 of the cavity resonance type power transmitter 100, and is configured to wirelessly feed power from the power transmitter 20 to a product 31 via the power receiver 30. The cavity resonance type power transmitter 100 includes the structure 10 entirely surrounded by a conductive electromagnetic wave shielding member, the power transmitter 20 that wirelessly feeds power to the product 31 via the power receiver 30 disposed in the internal space of the structure 10, and a partition 40 that separates the power receiver 30 and the power transmitter 20.

[0023] The structure 10 has, for example, a rectangular parallelepiped shape and includes a bottom 11, a top 12 facing the bottom 11, and a side 13 connecting the outer edges of the bottom 11 and the top 12. The bottom 11 and the top 12 face each other in the Z direction, with the bottom 11 located lower in the Z direction and the top 12 located upper in the Z direction. The bottom 11 and the top 12 are, for example, surfaces parallel to the XY plane, as shown in FIG. 1 . As shown in FIG. 1 , the structure 10 preferably has a shape whose longitudinal direction extends in the Z direction from the bottom 11 to the top 12. The shape of the structure 10 is not limited to a rectangular parallelepiped shape, and may be, for example, a pentagonal prism shape in which the XY plane is a pentagon, a quadrangular prism shape in which the XY plane is a trapezoid, or a semicircular cylinder shape in which the XY plane is a semicircle. However, in any of these shapes, it is preferable that the longitudinal direction extend in the Z direction from the bottom 11 to the top 12.

[0024] The cavity resonance type power transmission device 100 utilizes a resonance mode in the structure 10. The structure 10 has an internal space shielded by an electromagnetic wave shielding member, and can be considered as a resonator. When the resonator has a width dimension a (X direction), a length dimension b (Y direction), and a vertical dimension c (Z direction), the resonance frequency f ｒ can be determined as in Equation 1.

[0025] [Formula 1] f ｒ = v / (2π × (μｒ ×ε ｒ ) １／２ ) × {(mπ / a) ２ +(nπ / b) ２ +(pπ / c) ２} １／２

[0026] where v is the speed of light, μ ｒ is the relative permeability, ε ｒ In the cavity resonance type power transmitting device 100, m is an index in the width direction (X direction) of the resonator (structure 10), n is an index in the length direction (Y direction) of the resonator (structure 10), and p is an index in the vertical direction (Z direction) of the resonator (structure 10).

[0027] The material of the electromagnetic wave shielding member is not particularly limited as long as it is conductive, but preferred examples include metal materials such as copper, aluminum, iron, stainless steel, and nickel. Other examples include conductive oxide materials such as zinc oxide, titanium oxide, and indium tin oxide (ITO), graphite, and organic conductive materials. Furthermore, alloys or mixtures may also be used as long as they are conductive. The electromagnetic wave shielding member may have a multilayer structure made of these materials.

[0028] The electromagnetic wave shielding member may be in the form of a plate, mesh, film, porous, or the like, as long as it shields electromagnetic waves at the frequency at which power is supplied. Furthermore, the electromagnetic wave shielding member may be covered with an electromagnetic wave-transmitting material for purposes such as surface protection. Note that the electromagnetic wave shielding provided by the electromagnetic wave shielding member only needs to shield electromagnetic waves at the frequency used for wireless power transmission. In other words, it is also possible to use the member without shielding against communications at frequencies other than the frequency used for wireless power transmission.

[0029] 1 , the power transmitter 20 is provided in the center of the bottom 11 of the structure 10, in contact only with the inner surface of the bottom 11. The position of the power transmitter 20 may be in contact with the inner surface of the side portion 13, as long as it is in contact with the inner surface of the bottom 11. Furthermore, the position of the power transmitter 20 may be shifted from the center of the bottom 11 of the structure 10.

[0030] The configuration of the power transmitter 20 will be described with reference to Fig. 2. Fig. 2 is a schematic diagram of an example of a power transmitter according to the present invention. The power transmitter 20 includes, for example, a metal rod 21 and a power transmitting antenna wiring 22 arranged perpendicular to the metal rod 21. The metal rod 21 is preferably installed substantially perpendicular to the electromagnetic shielding member. In this case, the metal rod 21 is installed so as not to be in electrical contact with the electromagnetic shielding member, and penetrates the electromagnetic shielding member to be electrically connected to a matching circuit and a high-frequency power source (not shown) installed outside the resonator (structure 10).

[0031] The matching circuit is connected between the power transmitter 20 and the high-frequency power source. The matching circuit is adjusted to achieve impedance matching with the resonator at a preset power transmission frequency. Note that if the reference potentials of the matching circuit and the high-frequency power source are substantially the same as the reference potential of the electromagnetic wave shielding material, a connector such as an SMA (Sub Miniature Type A) terminal may be used for connection as appropriate. If the reference potentials of the matching circuit and the high-frequency power source are different from the reference potential of the electromagnetic wave shielding material, a similar effect can be achieved by using a dipole antenna 37 or a loop antenna (not shown), as with the power receiver 30 described below. The power transmitting antenna wiring 22 may be wired on a printed circuit board or the like, or may be wired by bending the metal rod 21. The power transmitting antenna wiring 22 may also be bent as appropriate within the wiring plane. It is preferable that the power transmission antenna wiring 22 be formed approximately parallel to the wall surface of the resonator (structure 10) made of an electromagnetic wave shielding material when power is transmitted using an electric field, and approximately perpendicular to the wall surface of the resonator (structure 10) made of an electromagnetic wave shielding material when power is transmitted using a magnetic field.

[0032] The partition 40 is, for example, a flat plate with a rectangular main surface, as shown in FIG. 1 . The partition 40 is preferably provided so that the main surface is parallel to the bottom 11 of the structure 10. In FIG. 1 , the partition 40 has four legs 41 with ends joined to the four corners of the rectangle, and the other ends of the legs 41 are in contact with the bottom 11 of the structure 10. The other ends of the legs 41 may be fixed to the bottom 11 of the structure 10. The shape of the main surface of the partition 40 may be the same as the bottom 11 of the structure 10. In this case, the edge of the main surface of the partition 40 may be joined to the inside of the side 13 of the structure 10. The partition 40 may also be a flat plate with a shape other than a rectangle. The partition 40 is preferably made of a material that is insulating in the resonant frequency band used in the present invention. Examples of such materials include synthetic resin materials, paper, and wood, but more preferable materials include fluororesin and polystyrene resin with a low dielectric constant. If mechanical strength allows, the partition 40 does not have to be bulky like polystyrene foam.

[0033] If the power receiver 30 is too close to the power transmitter 20, the impedance change becomes significant, the resonant frequency shifts, and charging becomes insufficient. In order to separate the power receiver 30 and the power transmitter 20, the partition 40 is spaced apart from the power transmitter 20 in FIG. 1 . The separation distance between the partition 40 and the power transmitter 20 is preferably at least ⅓ of the wavelength of the resonant frequency used for wireless power transfer. Meanwhile, the upper limit of the separation distance between the partition 40 and the power transmitter 20 is a position that allows the antenna of the power receiver 30 (described below) to be separated from the top 12 by at least ⅓ of the wavelength of the resonant frequency used for wireless power transfer. The resonant frequency used for wireless power transfer is, for example, 2.00 GHz or more and 3.00 GHz or less. When the resonant frequency is in the above range, the wavelength is 99.93 mm or more and 149.90 mm or less. The partition 40 is preferably disposed closer to the bottom 11 than to the top 12 in order to provide a larger space for arranging the power receiver 30 .

[0034] The partition 40 may be in contact with the power transmitter 20. In this case, the partition 40 preferably has a thickness in the Z direction that is equal to or greater than one-third of the wavelength of the resonant frequency used for wireless power feeding in order to separate the power receiver 30 and the power transmitter 20. The partition 40 may have a space inside.

[0035] In the cavity resonance type power transmitting device 100, it is preferable that a guide 50 is provided in the region of the internal space where the power receiver 30 is placed, to limit the position and direction of the power receiver 30. The guide 50 is, for example, a rectangular plate-shaped member, and recesses into which the power receivers 30 are fitted are evenly provided on the main surface. When a plurality of power receivers 30 are provided in the internal space, it is preferable that the guide 50 is provided so that power is fed evenly to all of the power receivers 30. When the mode has a characteristic power feeding direction, such as TE110, it is preferable to limit the direction of the power receiver 30.

[0036] In FIG. 1 , the guide 50 is fixed vertically to the upper main surface of the partition 40. Instead of being fixed to the partition 40, the guide 50 may be fitted into a frame (not shown) on the upper main surface of the partition 40 so that the guide 50 can be inserted into and removed from the cavity resonance type power transmitter 100. Fitting the guide 50 into the frame can fix the position of the guide 50 within the cavity resonance type power transmitter 100. When the guide 50 is a plate-like member, there may be one or more guides 50 in the internal space. When there are two or more guides 50, they may be arranged side by side in the Y direction, for example, but this is not particularly limited. The shape of the guide 50 is not limited to a plate-like member, as long as it limits the position and direction of the power receiver 30.

[0037] 1 , three power receivers 30 are arranged in the X direction and ten in the Z direction within the cavity resonance type power transmitter 100. The number and arrangement direction of the power receivers 30 are not particularly limited, but from the viewpoint of efficiency, it is preferable that a plurality of power receivers 30 are provided, that a plurality of power receivers 30 are arranged in the Z direction, and that all of the power receivers 30 are oriented in the same direction.

[0038] The configuration of the power receiver 30 will be described with reference to FIG. 3. FIG. 3 is a schematic diagram of an example of a power receiver according to the present invention. The power receiver 30 is composed of, for example, an electrical wiring section 37 serving as an antenna and a rectifier circuit 38. A switch, a matching circuit, and the like may be attached as necessary. A dipole antenna 37 or a loop antenna (not shown) is typically suitable as the antenna. The dipole antenna 37 may be bent as appropriate. An inverted F-type structure may also be employed, in which part of the wiring is short-circuited to the ground or a part that serves as the reference potential of the power receiver 30. The corresponding frequency can also be adjusted by inserting a capacitor or inductor into part of the antenna wiring. These may be selected according to the resonant frequency derived from the resonator formed by the electromagnetic wave shielding material.

[0039] 1, a product 31 equipped with a power receiver 30 therein is disposed in the internal space of the structure 10. Examples of the product 31 include electronic devices such as wireless earphones, smart watches, electronic pens, rechargeable toys, power tools, drive recorders, laptops, remote controls, IoT devices such as drones, smart meters, wireless speakers, batteries, and sensor modules.

[0040] The power receiver 30 may be separable from the product 31 as shown in Fig. 4. Fig. 4 is a schematic diagram of an example of a power receiver and a product according to the present invention. The wireless power transmission system 500 may be configured to connect the power receiver 30 to a charging terminal provided on the product 31 and wirelessly supply power to the product 31 and the power receiver 30 in a state where the product 31 and the power receiver 30 are disposed in the internal space of the structure 10.

[0041] In the cavity resonance type power transmitting device 100, it is preferable to transmit power by switching at least one of the indexes m and n of the resonance frequencies in the internal space between odd and even numbers. In this specification, 0 is not included in the even numbers. The indexes m and n are preferably odd or even numbers greater than or equal to 1 and less than or equal to 10, and more preferably odd or even numbers greater than or equal to 1 and less than or equal to 5. Specific examples include TE110, TE210, and TE120.

[0042] The index values ​​and the electric field intensity distribution will be described with reference to FIG. 5 . FIG. 5 is a schematic diagram showing an example of the electric field intensity distribution of the TE mode in the internal space of a cavity resonance type power transmitter. As shown in FIG. 5 , in the TE110 mode where the indexes m and n are 1 and p is 0, the electric field is strong in the central portion of the internal space in the X direction. In the TE210 mode where the indexes m is 2, n is 1, and p is 0, the electric field is weak in the central portion of the internal space in the X direction, and the electric field around that portion is strong. In the TE310 mode where the indexes m is 3, n is 1, and p is 0, regions of strong electric field, weak electric field, and strong electric field appear from the central portion to both ends in the X direction. By switching at least one of the indexes m and n between odd and even numbers during power transmission, it is possible to transmit power uniformly and efficiently to all power receivers 30, even when multiple power receivers are arranged over a wide range in the X and Y directions.

[0043] The cavity resonance type power transmitting device 100 preferably has a resonant frequency in the internal space in the TE110 mode, because when a plurality of power receivers are arranged in the Z direction from the bottom to the top, power can be efficiently supplied to all of the power receivers.

[0044] When the cavity resonance type power transmitting device 100 has a resonant frequency in the (m, n, p) mode, it is preferable to transmit power by switching so that any one of m, n, and p is 0. When any one of m, n, and p is 0, the electric field in the direction of 0 becomes constant. Therefore, by transmitting power by switching, it is possible to transmit power uniformly to all of the power receivers 30 even when the multiple power receivers 30 are randomly arranged.

[0045] In the cavity resonance type power transmitter 100, it is preferable to switch the resonant frequency at intervals of 0.3 seconds or more. Switching the resonant frequency at intervals of 0.3 seconds or more ensures sufficient power and allows the DC / DC converter that operates the power transmitter to operate normally. On the other hand, it is preferable to switch the resonant frequency at intervals of 1 second or less.

[0046] A wireless power transmission system 510 according to a second embodiment of the present invention will be described below with reference to Fig. 6. Only differences from the wireless power transmission system 500 will be described.

[0047] Fig. 6 is a schematic perspective view showing an example of a wireless power transmission system according to a second embodiment of the present invention. The wireless power transmission system 510 includes a cavity resonance type power transmitter 110. The cavity resonance type power transmitter 110 does not include a guide 50. In the wireless power transmission system 510 shown in Fig. 6, a product 31 including a power receiver 30 therein is packaged in a box 32, and the box 32 is placed directly on a main surface of a partition 40. Three boxes 32 are arranged in the X direction, and five boxes 32 are stacked in the Z direction. The number and arrangement of the boxes 32 placed on the partition 40 are not particularly limited, but it is preferable that a plurality of boxes 32 are stacked in the Z direction.

[0048] In order to transmit power evenly to the multiple power receivers 30, it is preferable that the orientation of the power receivers 30 is uniform, but the orientation of the power receivers 30 does not have to be uniform. The product 31 equipped with the power receiver 30 inside does not have to be packed in the box 32.

[0049] A wireless power transmission system 520 according to a third embodiment of the present invention will be described below with reference to Fig. 7. Only differences from the wireless power transmission system 510 will be described.

[0050] FIG. 7 is a schematic perspective view illustrating an example of a wireless power transmission system according to a third embodiment of the present invention. The wireless power transmission system 520 includes a cavity resonance type power transmitter 120. In the cavity resonance type power transmitter 120, a shelf 42 for placing a power receiver 30 is further provided between the partition 40 and the top 12. As shown in FIG. 7 , the shelf 42 is, for example, a rectangular flat plate whose main surface has the same area as the partition 40. The shelf 42 is preferably provided so that its main surface is parallel to the main surface of the partition 40. In FIG. 7 , the shelf 42 has four legs 43, the ends of which are joined to the four corners of the rectangle, and the other ends of the legs 43 are in contact with the main surface of the partition 40 on the top 12 side. The other ends of the legs 43 may be fixed to the partition 40. The shelf 42 may have the same shape as the bottom 11 of the structure 10, in which case the edge of the main surface of the shelf 42 may be joined to the inside of the side 13 of the structure 10. The shelf 42 may be a flat plate having a shape other than a rectangle. Two or more shelves 42 may be provided spaced apart in the Z direction.

[0051] In the cavity resonance type power transmitting device 120, the products 31 each having a power receiver 30 therein are packed in boxes 32, and three boxes 32 are arranged in the X direction on the main surface of the partition 40 and on the main surface of the shelf 42. The number and arrangement of the boxes 32 on the partition 40 and the shelf 42 are not particularly limited. For example, a plurality of boxes 32 may be stacked in the Z direction on each of the partition 40 and the shelf 42. Furthermore, no boxes 32 may be placed on the partition 40.

[0052] In contrast to the wireless power transmission system 520 shown in FIG. 7 , in the wireless power transmission system 500 shown in FIG. 1 , the power receiver 30 and the product 31 are in an unpackaged state, and the power transmitter 20 is configured to wirelessly supply power to the product 31 via the unpackaged power receiver 30.

[0053] A wireless power transmission system 600 according to a fourth embodiment of the present invention will be described below with reference to Fig. 8. Only differences from the wireless power transmission system 500 will be described.

[0054] FIG. 8 is a schematic cross-sectional view showing an example of a wireless power transmission system according to a fourth embodiment of the present invention. The wireless power transmission system 600 includes a cavity resonance type power transmitter 200. The structure 10 has, for example, a rectangular parallelepiped shape and includes a bottom 11, a top 12 facing the bottom 11, a first side 14 connecting the outer edges of the bottom 11 and the top 12, and a second side 15 facing the first side 14. The structure 10 further includes a third side 16 adjacent to the first side 14 or the second side 15, and a fourth side (not shown) facing the third side 16. As shown in FIG. 8, the structure 10 preferably has a shape having a longitudinal direction extending from the first side 14 to the second side 15. The shape of the structure 10 of this embodiment is not limited to a rectangular parallelepiped shape, and may be, for example, a pentagonal prism shape in which the XY planes are pentagonal, a quadrangular prism shape in which the XY planes are trapezoidal, or a semi-cylinder shape in which the XY planes are semicircular. In any of these shapes, however, it is preferable that the shape has a longitudinal direction in the Y direction from the first side portion 14 to the second side portion 15.

[0055] In the cavity resonance type power transmitting device 200, the power transmitter 20 is provided in contact with the inner surface of the bottom portion 11 and the inner surface of the first side portion 14. In the cavity resonance type power transmitting device 200, when the width of the resonator (structure 10) is a (X direction) and b (Y direction) and the vertical length is c (Z direction), the resonance frequency f ｒ can be determined as in Equation 2.

[0056] [Formula 2] f ｒ = v / (2π × (μ ｒ ×ε ｒ ) １／２ ) × {(mπ / a) ２ +(pπ / b) ２ +(nπ / c) ２} １／２

[0057] where v is the speed of light, μ ｒ is the relative permeability, ε ｒIn the cavity resonance type power transmitting device 200, m is an index in the width direction (X direction) of the resonator (structure 10), n is an index in the vertical direction (Z direction) of the resonator (structure 10), and p is an index in the length direction (Y direction) of the resonator (structure 10).

[0058] In the cavity resonance type power transmitter 200, the partition 40 is preferably a flat plate having the same height as the first side portion 14 of the structure 10 and is provided so as to be parallel to the first side portion 14. In Fig. 8 , the edges of the partition 40 are in contact with the bottom portion 11 and the top portion 12 of the structure 10. The partition 40 is preferably disposed closer to the first side portion 14 than to the second side portion 15 in order to provide a larger space for arranging the power receiver 30.

[0059] Next, a wireless power transmission system 610, which is a modification of the fourth embodiment, will be described below with reference to Fig. 9. Only the differences from the wireless power transmission system 600 will be described here.

[0060] 9 is a schematic cross-sectional view showing another example of a wireless power transmission system according to the fourth embodiment of the present invention. The wireless power transmission system 610 includes a cavity resonance type power transmitter 210. In the cavity resonance type power transmitter 210, the power transmitter 20 is disposed at the center of the inner surface of the first side portion 14, and is in direct contact with the inner surface of the first side portion 14 and indirect contact with the inner surface of the bottom portion 11. A footing 23 is provided below the power transmitter 20 to apply the weight of the power transmitter 20 to the bottom portion 11.

[0061] The wireless power transmission system of the present invention may include two or more cavity resonance type power transmitters. Fig. 10 is a cross-sectional schematic diagram showing another example of the wireless power transmission system of the present invention. The wireless power transmission system 611 includes three cavity resonance type power transmitters 210. As shown in Fig. 10, a plurality of the wireless power transmission systems 611 can be provided in the height direction by placing the cavity resonance type power transmitters 210 on a stand 300.

[0062] When the wireless power transmission system of the present invention includes two or more cavity resonance type power transmitters, it is preferable that at least one of the cavity resonance type power transmitters is the cavity resonance type power transmitter of the present invention, and it is more preferable that all of the cavity resonance type power transmitters are the cavity resonance type power transmitters of the present invention. When two or more cavity resonance type power transmitters are the cavity resonance type power transmitters of the present invention, all of them may be the cavity resonance type power transmitters of the same embodiment, or some or all of them may be cavity resonance type power transmitters of different embodiments.

[0063] The present invention also includes a cavity resonance type power transmitting device provided in the wireless power transmission system of the present invention.

[0064] The present specification discloses the following:

[0065] <1> A cavity resonance type power transmitting device comprising: a structure entirely surrounded by a conductive electromagnetic wave shielding member; a power transmitter that wirelessly supplies power to a product via a power receiver placed in an internal space of the structure; and a partition that separates the power receiver and the power transmitter, wherein the structure has a bottom, a top that faces the bottom, and a side that connects outer edges of the bottom and the top, and the power transmitter is provided in contact with the inner surface of the bottom.

[0066] <2> The cavity resonance type power transmitting device according to <1>, wherein the partition is provided at a distance from the power transmitter.

[0067] <3> The cavity resonance type power transmitting device according to <1> or <2>, wherein the separation distance between the partition and the power transmitter is equal to or greater than one-third of the wavelength of a resonance frequency used for wireless power feeding.

[0068] <4> The cavity resonance type power transmitting device according to any one of <1> to <3>, wherein a guide for restricting the position and direction of the power receiver is provided in an area of ​​the internal space where the power receiver is placed.

[0069] <5> The cavity resonance type power transmitting device according to any one of <1> to <4>, wherein power is transmitted by switching at least one of the indexes m and n of the resonance frequency in the internal space between odd and even numbers.

[0070] <6> The cavity resonance type power transmitting device according to any one of <1> to <5>, wherein when the resonance frequency is in an (m, n, p) mode, power is transmitted by switching so that one of m, n, and p becomes 0.

[0071] <7> The cavity resonance type power transmitting device according to <5> or <6>, wherein the resonant frequency is switched at intervals of 0.3 seconds or more.

[0072] <8> The cavity resonance type power transmitting device according to any one of <1> to <7>, wherein the power transmitter is provided in contact only with the inner surface of the bottom of the structure.

[0073] <9> The cavity resonance type power transmitting device according to any one of <1> to <8>, wherein the structure has a shape having a longitudinal direction from the bottom to the top.

[0074] <10> The cavity resonance type power transmitting device according to <9>, wherein the partition is disposed closer to the bottom than to the top.

[0075] <11> The cavity resonance type power transmitting device according to <9> or <10>, further comprising a shelf for placing the power receiver between the partition and the top.

[0076] <12> The cavity resonance type power transmitting device according to any one of <1> to <11>, wherein the resonance frequency in the internal space is a TE110 mode.

[0077] <13> The cavity resonance type power transmitting device according to any one of <1> to <7>, wherein the side of the structure has a first side and a second side facing the first side, and the power transmitter is provided in contact with an inner surface of the bottom and an inner surface of the first side.

[0078] <14> The cavity resonance type power transmitting device according to <13>, wherein the structure has a shape having a longitudinal direction extending from the first side portion to the second side portion.

[0079] <15> The cavity resonance type power transmitting device according to <13> or <14>, wherein the partition is disposed closer to the first side portion than to the second side portion.

[0080] <16> The cavity resonance type power transmitting device according to any one of <13> to <15>, wherein the power transmitter is provided in indirect contact with the inner surface of the bottom portion and in direct contact with the inner surface of the first side portion.

[0081] <17> A wireless power transmission system comprising: the cavity resonance type power transmitter according to any one of <1> to <16>; and a power receiver disposed in an internal space of a structure of the cavity resonance type power transmitter, wherein the wireless power transmission system is configured to wirelessly supply power to a product from the power transmitter via the power receiver.

[0082] <18> The wireless power transmission system according to <17>, wherein a plurality of the power receivers are provided.

[0083] <19> The wireless power transmission system according to <17> or <18>, wherein the power receiver is separable from the product, the power receiver is connected to a charging terminal provided in the product, and power is supplied wirelessly to the product while the product is placed in the internal space of the structure.

[0084] <20> The wireless power transmission system according to any one of <17> to <19>, wherein the power receiver is in an unpackaged state, and the power transmitter wirelessly supplies power to the product via the unpackaged power receiver.

[0085] <21> The wireless power transmission system according to any one of <17> to <19>, wherein the power receiver and the product are packaged, and the power transmitter wirelessly supplies power to the product via the packaged power receiver.

[0086] <22> The wireless power transmission system according to <21>, wherein the power receiver and the product are stacked on a partition in a packaged state.

[0087] DESCRIPTION OF SYMBOLS 10 Structure 11 Bottom 12 Top 13 Side 14 First side 15 Second side 16 Third side 20 Power transmitter 21 Metal rod 22 Power transmission antenna wiring 23 Scaffolding 30 Power receiver 31 Product 32 Box 37 Dipole antenna (electrical wiring section) 38 Rectifier circuit 40 Partition 41, 43 Leg 42 Shelf 50 Guide 100, 110, 120, 200, 210 Cavity resonance type power transmission device 300 Frame 500, 510, 520, 600, 610, 611 Wireless power transmission system

Claims

1. A cavity resonant type power transmitting device comprising a structure entirely surrounded by a conductive electromagnetic wave shielding material, a power transmitter that wirelessly supplies power to a product via a power receiver placed in the internal space of the structure, and a partition that separates the power receiver and the power transmitter, wherein the structure has a bottom, a top opposite the bottom, and a side that connects the outer edges of the bottom and the top, and the power transmitter is provided in contact with the inner surface of the bottom.

2. The cavity resonance type power transmitting device according to claim 1, wherein the partition is provided at a distance from the power transmitter.

3. A cavity resonance type power transmitting device according to claim 1 or 2, wherein the distance between the partition and the power transmitter is equal to or greater than 1 / 3 of the wavelength of the resonant frequency used for wireless power supply.

4. A cavity resonance type power transmission device according to any one of claims 1 to 3, wherein a guide for restricting the position and orientation of the power receiver is provided in an area of ​​the internal space in which the power receiver is placed.

5. A cavity resonance type power transmitting device according to any one of claims 1 to 4, which transmits power by switching at least one of the indexes m and n of the resonance frequencies in the internal space between odd and even numbers.

6. A cavity resonance type power transmitting device according to any one of claims 1 to 5, which transmits power by switching so that any one of m, n, and p becomes 0 when the resonant frequency is in the (m, n, p) mode.

7. A cavity resonance type power transmitting device according to claim 5 or 6, characterized in that the resonant frequency is switched at intervals of 0.3 seconds or more.

8. A cavity resonance type power transmitting device according to any one of claims 1 to 7, wherein the power transmitter is provided in contact only with the inner surface of the bottom of the structure.

9. A cavity resonance type power transmitting device according to any one of claims 1 to 8, wherein the structure has a shape having a longitudinal direction from the bottom to the top.

10. A cavity resonance type power transmitting device according to claim 9, wherein the partition is disposed closer to the bottom than to the top.

11. The cavity resonance type power transmitting device according to claim 9 or 10, further comprising a shelf between the partition and the top for placing the power receiver thereon.

12. A cavity resonance type power transmitting device according to any one of claims 1 to 11, wherein the resonance frequency in the internal space is a TE110 mode.

13. A cavity resonant type power transmitting device as described in any one of claims 1 to 7, wherein the side of the structure has a first side and a second side opposite the first side, and the power transmitter is provided in contact with the inner surface of the bottom and the inner surface of the first side.

14. A cavity resonator type power transmitting device according to claim 13, wherein the structure has a shape having a longitudinal direction extending from the first side portion to the second side portion.

15. A cavity resonance type power transmitting device according to claim 13 or 14, wherein the partition is disposed closer to the first side portion than to the second side portion.

16. A cavity resonant type power transmitting device according to any one of claims 13 to 15, wherein the power transmitter is provided in indirect contact with the inner surface of the bottom portion and in direct contact with the inner surface of the first side portion.

17. A wireless power transmission system comprising: a cavity resonance type power transmitter according to any one of claims 1 to 16; and a power receiver arranged in an internal space of a structure of the cavity resonance type power transmitter, configured to wirelessly supply power to a product from the power transmitter via the power receiver.

18. The wireless power transmission system according to claim 17, comprising a plurality of the power receivers.

19. A wireless power transmission system as described in claim 17 or 18, wherein the receiver is separable from the product, the receiver is connected to a charging terminal provided on the product, and power is supplied wirelessly to the product while the product is placed in the internal space of the structure.

20. A wireless power transmission system as described in any one of claims 17 to 19, wherein the receiver is in an unpackaged state, and the transmitter wirelessly supplies power to the product via the receiver in the unpackaged state.

21. A wireless power transmission system according to any one of claims 17 to 19, wherein the receiver and the product are in a packaged state, and the transmitter wirelessly supplies power to the product via the receiver in the packaged state.

22. The wireless power transmission system according to claim 21, wherein the receiver and the product are stacked on a partition in a packaged state.

Images