Wireless power transmission device

Abstract

A wireless power transmission device (10) comprises: an extracorporeal housing (20) having a first wall (21) on the side that faces a living body and a second wall (22) on the opposite side from the living body; a power transmission coil (131) disposed in the extracorporeal housing (20); a power transmission resonance capacitor (132) constituting a resonance circuit with the power transmission coil (131); a magnetic sheet (30) disposed in the extracorporeal housing (20); and a power transmission circuit board (129) disposed in the extracorporeal housing (20) and on which a power semiconductor element (120) handling DC power supply is mounted. The power transmission coil (131), the magnetic sheet (30), and the power transmission circuit board (129) are arranged in this order from the first wall (21) to the second wall (22). The power transmission circuit board (129) has a mounting surface (1291) for the power semiconductor element (120) facing the magnetic sheet (30). The wireless power transmission device (10) comprises: a first TIM material (41) that is disposed between the power semiconductor element (120) and the magnetic sheet (30) and abuts the power semiconductor element (120) and the magnetic sheet (30); a second TIM material (42) that is disposed between the power transmission circuit board (129) and the second wall (22) and abuts the power transmission circuit board (129) and the second wall (22); and a heat insulation sheet (50) that is disposed closer to the first wall (21) side than the power transmission coil (131). The wireless power transmission device (10) forms a first heat path (HP1) that passes through the first TIM material (41) and has a first average thermal resistance. The wireless power transmission device (10) forms a second heat path (HP2) that passes through the second TIM material (42) and has a second average thermal resistance. The wireless power transmission device (10) forms a third heat path (HP3) including the heat insulation sheet (50) and having a third average thermal resistance. The third average thermal resistance is greater than the first average thermal resistance and the second average thermal resistance.

Description

Wireless power transmission device

[0001] The present invention relates to an implantable medical device that is implanted in a living body such as a human or animal body and receives power wirelessly from outside the body.

[0002] In recent years, implantable medical devices for neurostimulation, neurosensing, etc. have been researched and developed. These implantable medical devices are becoming increasingly multifunctional and multichannel.

[0003] This increases power consumption and increases the burden on patients due to battery replacement, which has led to the need to implement wireless power transfer in implantable medical devices.

[0004] As an example of a general wireless power supply, Patent Document 1 describes a system that wirelessly supplies power to drive units that are externally attached to both feet of a person.

[0005] JP 2010-258437 A

[0006] The power consumption of implantable medical devices is increasing due to their increasing functionality. For this reason, wireless power transmitters for implantable medical devices are required to achieve high power efficiency in their wireless power supply systems. In wireless power transmitters for implantable medical devices, when the transmitted power increases, the power loss becomes Joule heat, generating heat, which tends to result in a large temperature rise.

[0007] For this reason, wireless power transmitters for implantable medical devices require temperature control and suppression of heat that affects the living body in which the medical device is implanted. In particular, power transmitters for medical devices are required to be waterproof and dustproof, and require a sealed structure. The sealed structure makes temperature rise in the wireless power transmitter, which contains a power transmission circuit and power transmission coil that act as a heat source, even more problematic, making it necessary to suppress heat that affects the living body and to further manage the temperature.

[0008] An object of the present invention is to provide a wireless power transmission device for an implantable medical device that achieves high power efficiency in wireless power supply while suppressing the effects of heat generation that affects the living body and suppressing temperature rise in the living body.

[0009] A wireless power transmitter according to one embodiment of the present invention includes an extracorporeal housing having a first wall facing a living body and a second wall facing away from the living body, a power transmitting coil disposed within the extracorporeal housing, a power transmitting resonant capacitor forming a resonant circuit together with the power transmitting coil, a magnetic sheet disposed within the extracorporeal housing, and a power transmitting circuit board mounted with a power semiconductor element that handles a DC power supply. The power transmitting coil, magnetic sheet, and power transmitting circuit board are disposed in this order from the first wall toward the second wall.

[0010] The power transmission circuit board has a mounting surface for the power semiconductors facing the magnetic sheet.

[0011] The wireless power transmission device includes a first TIM material arranged between the power semiconductor element and the magnetic sheet and in contact with the power semiconductor element and the magnetic sheet, a second TIM material arranged between the power transmission circuit board and the second wall and in contact with the power transmission circuit board and the second wall, and a heat insulating sheet arranged closer to the first wall than the power transmission coil, or a gap between the power transmission coil and the first wall.

[0012] The wireless power transmitter forms a first thermal path through the first TIM material and has a first average thermal resistance. The wireless power transmitter forms a second thermal path through the second TIM material and has a second average thermal resistance. The wireless power transmitter includes an insulating sheet or an air gap and forms a third thermal path having a third average thermal resistance. The third average thermal resistance is greater than the first and second average thermal resistances.

[0013] A wireless power transmitter according to one embodiment of the present invention includes an extracorporeal housing having a first wall facing a living body and a second wall facing away from the living body, a power transmitting coil disposed within the extracorporeal housing, a power transmitting resonant capacitor forming a resonant circuit together with the power transmitting coil, a magnetic sheet disposed within the extracorporeal housing, and a power transmitting circuit board mounted with a power semiconductor element that handles a DC power supply. The power transmitting coil, magnetic sheet, and power transmitting circuit board are disposed in this order from the first wall toward the second wall.

[0014] The power transmitting circuit board has a mounting surface for the power semiconductor devices facing the second wall.

[0015] The wireless power transmission device includes a first TIM material arranged between the power transmission circuit board and the magnetic sheet and in contact with the power transmission circuit board and the magnetic sheet, a second TIM material arranged between the power semiconductor element and the second wall and in contact with the power semiconductor and the second wall, and a heat insulating sheet arranged closer to the first wall than the power transmission coil, or a gap between the power transmission coil and the first wall.

[0016] The wireless power transmitter forms a first thermal path through the first TIM material and has a first average thermal resistance. The wireless power transmitter forms a second thermal path through the second TIM material and has a second average thermal resistance. The wireless power transmitter includes an insulating sheet or an air gap and forms a third thermal path having a third average thermal resistance. The third average thermal resistance is greater than the first and second average thermal resistances.

[0017] In these configurations, the wireless power transmitter conducts heat generated in the power semiconductor to the magnetic sheet via a first heat path, suppressing the local temperature on the first wall side through thermal diffusion by the magnetic sheet. The wireless power transmitter conducts heat generated in the power semiconductor to the second wall via a second heat path, and radiates heat from the second wall to the outside of the housing, suppressing heat generation. The wireless power transmitter insulates heat that reaches the first heat path from the first wall side through a third heat path, suppressing heat generation in a living body. The wireless power transmitter increases the power efficiency of electromagnetic field coupling resonance wireless power transfer through a magnetic path formed by the arrangement of the power transmission coil and magnetic sheet, suppressing heat generation due to power loss. The wireless power transmitter suppresses the impact of heat generation on a living body through temperature management of heat conduction, thermal diffusion, heat radiation, and insulation via the first, second, and third heat paths.

[0018] According to this invention, the wireless power transmission device of the present invention achieves high power efficiency in electromagnetic field resonance wireless power supply operation through electromagnetic field coupling using the electromagnetic field resonance phenomenon, while its temperature management structure suppresses the effects of heat generation that affects living organisms and suppresses temperature rise in the living organism.

[0019] FIG. 1 is a functional block diagram showing a schematic configuration of a wireless power supply system according to a first embodiment of the present invention. FIG. 2 is a side cross-sectional view showing the configuration of a wireless power transmission device according to the first embodiment. FIG. 3 is an exploded perspective view of the wireless power transmission device according to the first embodiment. FIG. 4(A) is a diagram showing an overview of thermal paths, and FIG. 4(B) is a diagram showing an example of the state of heat conduction in each thermal path. FIG. 5 is a side cross-sectional view showing the configuration of a wireless power transmission device according to a second embodiment. FIG. 6 is a side cross-sectional view showing the configuration of a wireless power transmission device according to a third embodiment. FIG. 7 is a side cross-sectional view showing the configuration of a wireless power transmission device according to a fourth embodiment. FIG. 8 is a side cross-sectional view showing the configuration of a wireless power transmission device according to a fifth embodiment. FIG. 9 is a side cross-sectional view showing the configuration of a wireless power transmission device according to a sixth embodiment.

[0020] First Embodiment A wireless power supply system including a wireless power transmitting device according to a first embodiment of the present invention will be described with reference to the drawings.

[0021] (Functional Configuration of Wireless Power Supply System 1) Fig. 1 is a functional block diagram showing a schematic configuration of a wireless power supply system according to a first embodiment of the present invention. As shown in Fig. 1, the wireless power supply system 1 includes a wireless power transmitter 10 and a wireless power receiver 90.

[0022] Specifically, the wireless power receiving device 90 is an implantable medical device in vivo. The wireless power transmitting device 10 is placed outside the living body in which the wireless power receiving device 90 is implanted.

[0023] The wireless power transmitter 10 includes a power transmission circuit 12 and a power transmission resonant circuit 13 .

[0024] The power transmitting circuit 12 is connected to a DC power source. The power transmitting circuit 12 includes a power semiconductor element 120. The power semiconductor element 120 is a semiconductor including a switching element. The power transmitting circuit 12 converts DC power from the DC power source into AC power of a predetermined frequency by controlling the switching of the switching element at a predetermined frequency (operating frequency), thereby generating a transmission current. The power transmitting circuit 12 supplies the transmission current to the power transmitting resonant circuit 13.

[0025] The power transmitting resonant circuit 13 includes a power transmitting coil 131 and a power transmitting resonant capacitor 132. The power transmitting coil 131 and the power transmitting resonant capacitor 132 are connected in series. The resonant frequency of the power transmitting resonant circuit 13 (power transmitting resonant frequency) is approximately the same as the frequency of the power transmitting current.

[0026] The power transmission coil 131 generates an alternating magnetic field at a resonant frequency due to the supplied power transmission current.

[0027] The wireless power receiving device 90 includes a power receiving resonant circuit 901, a power receiving circuit 991, and a load circuit 992. The load circuit 992 includes, for example, a sensor that acquires various measurement signals for medical use.

[0028] The power receiving resonant circuit 901 includes a power receiving coil 92 and a power receiving resonant capacitor 902. The power receiving coil 92 and the power receiving resonant capacitor 902 are connected in series. The resonant frequency of the power receiving resonant circuit 901 (power receiving resonant frequency) is approximately the same as the frequency of the alternating magnetic field, i.e., the power transmitting resonant frequency.

[0029] When the power receiving coil 92 is arranged so as to be coupled to an alternating magnetic field (see the magnetic path (dotted arrow) shown in FIG. 2), a receiving current flows through the power receiving coil 92 .

[0030] At this time, since the power transmitting resonant frequency, the frequency of the alternating magnetic field, and the power receiving resonant frequency are substantially the same, an electromagnetic resonant field is formed between the power transmitting coil 131 and the power receiving coil 92 .

[0031] As a result, the wireless power supply system 1 can achieve low-loss wireless power supply from the wireless power transmitter 10 to the wireless power receiver 90 .

[0032] The frequency bands of the power transmission resonance frequency, the frequency of the alternating magnetic field, and the power receiving resonance frequency, in other words, the operating frequency band of the power semiconductor, are preferably in the 6.78 MHz band or the 13.56 MHz band.

[0033] The power receiving resonant circuit 901 outputs a receiving current to the power receiving circuit 991. The power receiving circuit 991 rectifies and smoothes the receiving current at the power receiving resonant frequency, and supplies DC power to the load circuit 992. The load circuit 992 operates using the supplied DC power.

[0034] (Structure of wireless power transmitter 10 and wireless power receiver 90) Fig. 2 is a side cross-sectional view showing the configuration of a wireless power transmitter according to the first embodiment. Fig. 3 is an exploded perspective view of the wireless power transmitter according to the first embodiment. Note that Fig. 3 shows only a portion of the housing, and does not show electronic components other than the power semiconductors.

[0035] (General Structure of Wireless Power Receiver 90) First, before describing the structure of the wireless power transmitter 10, a portion of the structure of the wireless power receiver 90 will be described with reference to FIG.

[0036] The wireless power receiving device 90 includes a housing 91. The housing 91 has an enclosed space inside. The housing 91 is implanted in a living body. The housing 91 houses a power receiving coil 92, a power receiving magnetic sheet 93, and a power receiving electronic circuit board. The power receiving electronic circuit board is mounted with electronic circuit components that realize the above-mentioned power receiving resonant capacitor 902, a power receiving circuit 991, and electronic circuit components that realize a load circuit 992.

[0037] The housing 91 includes a window member 911 that is disposed on the surface side of the living body. The window member 911 is a flat plate that is disposed substantially parallel to the surface of the part of the living body where the wireless power receiving device 90 is to be implanted.

[0038] The power receiving coil 92 has a flat membrane shape and includes an annular conductor having an axis perpendicular to the membrane surface. The power receiving coil 92 is disposed adjacent to the window member 911.

[0039] The power-receiving-side magnetic sheet 93 has a flat film shape and is disposed adjacent to the power-receiving coil 92 on the side opposite the window member 911 of the power-receiving coil 92 .

[0040] The power receiving side electronic circuit board is disposed on the opposite side of the power receiving coil 92 side of the power receiving side magnetic sheet 93. With this configuration, the magnetic path of the alternating magnetic field is confined by the power receiving side magnetic sheet 93 on the wireless power receiving device 90 side (see the dotted arrow in FIG. 2 ), preventing the alternating magnetic field from leaking to the power receiving side electronic circuit board. This prevents a decrease in the power receiving efficiency of the wireless power receiving device 90.

[0041] The window member 911 is made of a non-metallic biocompatible material. Specifically, the window member 911 is made of sapphire glass, sapphire, ruby, glass, ceramic, or the like. Using such a material for the window member 911 can reduce effects on and from the living body. The power receiving coil 92 disposed within the housing 91 can be coupled to the alternating magnetic field generated by the power transmitting coil 131.

[0042] The portions of the housing 91 other than the window member 911 are made of Ti (titanium), a Ti (titanium) alloy (for example, Ti-6Al-4V), or the like. By using such a material for the portions of the housing 91 other than the window member 911, it is possible to suppress effects on and from the living body. Note that as a metallic biocompatible material, a material containing Ti (titanium) as the main component is preferred.

[0043] In contrast to the wireless power receiving device 90 having such a structure, the wireless power transmitting device 10 has the following structure.

[0044] (Structure of wireless power transmission device 10) As shown in Figures 2 and 3 , the wireless power transmission device 10 includes an extracorporeal housing 20, a magnetic sheet 30, a first TIM material 41, a second TIM material 42, a heat insulating sheet 50, a power semiconductor element 120, a plurality of electronic circuit components 128, a power transmission circuit board 129, a power transmission coil 131, a wiring pattern 139, and a power wiring cable 290.

[0045] The extracorporeal housing 20 includes a first wall 21 on the side facing the living body, a second wall 22 on the side facing away from the living body, and a side wall 23. The first wall 21 and the second wall 22 are, for example, rectangular in plan view. Note that the shapes of the first wall 21 and the second wall 22 are not limited to rectangular. The extracorporeal housing 20 is made of insulating resin that allows an electromagnetic field to pass through.

[0046] The first wall 21 has an outer surface 211 and an inner surface 212. The second wall 22 has an outer surface 221 and an inner surface 222. The outer surface 211 and the outer surface 221 face the outside of the extracorporeal casing 20, and the inner surface 212 and the inner surface 222 face the inside of the extracorporeal casing 20 (toward the internal space 200).

[0047] The side wall 23 is disposed along the outer periphery of the first wall 21 and the second wall 22 and is connected to the first wall 21 and the second wall 22. This allows the extracorporeal housing 20 to have an internal space 200. A ceiling 29 is formed in the second wall 22, and a power wiring cable 290 is drawn from the internal space 200 of the extracorporeal housing 20 to the outside through the ceiling 29.

[0048] With this configuration, the external housing 20 forms a substantially sealed internal space 200. This allows the external housing 20 to be waterproof and dustproof, and the wireless power transmitting device 10 has a configuration suitable for a power transmitting device for a medical device.

[0049] The power transmitting coil 131 has a flat membrane shape. The power transmitting coil 131 includes an annular conductor 1310 having an axis perpendicular to the flat membrane surface. The power transmitting coil 131 is positioned so that the flat membrane surface is parallel to the first wall 21 and the second wall 22 of the extracorporeal housing 20. The power transmitting coil 131 is electrically connected to the power transmitting circuit board 129 via a wiring pattern 139.

[0050] The power transmitting circuit board 129 has a flat plate shape. The power transmitting circuit board 129 has a configuration in which a conductor pattern is formed on an insulating base material. The power transmitting circuit board 129 has a mounting surface 1291 and a back surface 1292. The power semiconductor element 120 and the plurality of electronic circuit components 128 are mounted on the mounting surface 1291.

[0051] The magnetic sheet 30 has a flat film shape and is made of iron oxide or the like.

[0052] The first TIM material 41 and the second TIM material 42 have a flat film shape. TIM is an abbreviation for Thermal Interface Material. The first TIM material 41 and the second TIM material 42 are made of a material with high thermal conductivity, in other words, a material with high thermal conductivity. The thermal conductivity of the first TIM material 41 and the second TIM material 42 is, for example, 2.0 W / m·k or more. For example, the first TIM material 41 and the second TIM material 42 are made of an acrylic material, α-gel, Sarcon, or the like.

[0053] The heat insulating sheet 50 has a flat membrane shape. The heat insulating sheet 50 is made of a material with high heat insulating performance, in other words, a material with low thermal conductivity. The thermal conductivity of the heat insulating sheet 50 is, for example, 0.03 W / m·k or less.

[0054] The power transmission coil 131, the power transmission circuit board 129, the magnetic sheet 30, the first TIM material 41, the second TIM material 42, and the heat insulating sheet 50 are arranged in the internal space 200 of the extracorporeal housing 20. At this time, the power transmission coil 131, the power transmission circuit board 129, the magnetic sheet 30, the first TIM material 41, the second TIM material 42, and the heat insulating sheet 50 are arranged so that their respective flat membrane surfaces are parallel to the first wall 21 and the second wall 22.

[0055] The power transmission coil 131, the power transmission circuit board 129, the magnetic sheet 30, the first TIM material 41, the second TIM material 42, and the insulating sheet 50 are arranged in the following order from the first wall 21 to the second wall 22: insulating sheet 50, power transmission coil 131, magnetic sheet 30, the first TIM material 41, the power transmission circuit board 129, and the second TIM material 42.

[0056] More specifically, these have the following layout relationship with respect to the power semiconductor device 120.

[0057] First, the first wall 21 side from the power transmission circuit board 129 is as follows.

[0058] The power transmission circuit board 129 is arranged so that a mounting surface 1291 on which the power semiconductor element 120 is mounted faces the first wall 21. A first TIM material 41 is arranged on the first wall 21 side of the power semiconductor element 120.

[0059] The first TIM material 41 has an area equal to or larger than that of the power semiconductor element 120 in a plan view. The first TIM material 41 faces the top surface (the surface opposite to the mounting surface) of the power semiconductor element 120. The first TIM material 41 overlaps substantially the entire surface of the power semiconductor element 120 and abuts against the power semiconductor element 120.

[0060] The magnetic sheet 30 has an area larger than the first TIM material 41 in a plan view and is equal to or larger than the area of ​​the power transmitting coil 131. The magnetic sheet 30 faces the mounting surface 1291 of the power transmitting circuit board 129 and the first TIM material 41. The magnetic sheet 30 overlaps substantially the entire surface of the first TIM material 41 and abuts against the first TIM material 41.

[0061] The power transmission coil 131 faces the magnetic sheet 30. The power transmission coil 131 overlaps the magnetic sheet 30 and abuts against the magnetic sheet 30.

[0062] The heat insulating sheet 50 has an area equal to or larger than the power transmitting coil 131 in a plan view. The heat insulating sheet 50 faces the power transmitting coil 131. The heat insulating sheet 50 overlaps substantially the entire power transmitting coil 131 and abuts against the power transmitting coil 131.

[0063] The heat insulating sheet 50 faces and abuts against the inner surface 212 of the first wall 21. The heat insulating sheet 50 does not have to abut against the inner surface 212 of the first wall 21. However, by having the heat insulating sheet 50 abut against the inner surface 212 of the first wall 21, the distance between the power transmission coil 131 and the first wall 21 can be shortened.

[0064] Next, the second wall 22 side from the power transmission circuit board 129 is as follows.

[0065] The second TIM material 42 has an area, in plan view, equal to or larger than the power transmitting circuit board 129. The second TIM material 42 overlaps substantially the entire surface of the power transmitting circuit board 129 in plan view and abuts against the power transmitting circuit board 129.

[0066] The second TIM material 42 abuts the inner surface 222 of the second wall 22 .

[0067] In such a configuration, when the power semiconductor element 120 is driven and generates heat, the heat from the power semiconductor element 120, which is the heat source, is conducted as follows.

[0068] FIG. 4A is a diagram showing an outline of the heat paths, and FIG. 4B is a diagram showing an example of the heat conduction state in each heat path.

[0069] As shown in FIGS. 4A and 4B, the heat generated from the power semiconductor device 120 is conducted to the first wall 21 side and the second wall 22 side.

[0070] (First wall 21 side) On the first wall 21 side, heat from the power semiconductor element 120 is conducted to the first TIM material 41. The heat conducted to the first TIM material 41 is conducted to the magnetic sheet 30. The area of ​​the magnetic sheet 30 is larger than that of the first TIM material 41. That is, the heat conducted to the first TIM material 41 is diffused within the magnetic sheet 30.

[0071] The heat conduction path including the first TIM material 41 and the magnetic sheet 30 is the first heat path HP1.

[0072] The heat conducted to the surface of the magnetic sheet 30 that contacts the power transmission coil 131 is conducted to the power transmission coil 131. Note that the heat conducted to the portion of the magnetic sheet 30 other than the surface that contacts the power transmission coil 131 is diffused from the magnetic sheet 30 into the internal space 200, for example.

[0073] The heat conducted to the power transmission coil 131 reaches the surface of the heat insulating sheet 50 .

[0074] The heat conduction path including the power transmission coil 131 and the heat insulating sheet 50 is the third heat path HP3.

[0075] (Second Wall 22 Side) On the second wall 22 side, the heat of the power semiconductor element 120 is conducted to the second TIM material 42 through the power transmission circuit board 129. The heat conducted to the second TIM material 42 is conducted to the second wall 22.

[0076] The heat conduction path including the power transmission circuit board 129 and the second TIM material 42 is the second heat path HP2.

[0077] In this configuration, the first thermal path HP1 includes a first TIM material 41, the second thermal path HP2 includes a second TIM material 42, and the third thermal path HP3 includes an insulating sheet 50. Therefore, the first average thermal resistance of the first thermal path HP1 and the second average thermal resistance of the second thermal path HP2 are less than the third average thermal resistance of the third thermal path HP3.

[0078] As a result, on the second wall 22 side, heat from the power semiconductor element 120 is effectively conducted through the second thermal path HP2 to the second wall 22 of the extracorporeal housing 20. The heat conducted to the second wall 22 is mainly dissipated from the second wall 22 to the outside of the extracorporeal housing 20.

[0079] On the other hand, on the first wall 21 side, the heat generated by the power semiconductor element 120 is effectively conducted through the first thermal path HP1 to the power transmitting coil 131. However, the third thermal path HP3 prevents this heat from being conducted to the first wall 21. This prevents the temperature of the first wall 21 from rising.

[0080] The heat diffused through the first heat path HP1 and the heat blocked by the third heat path HP3 are diffused into the internal space 200. The heat conducted to the internal space 200 is dissipated to the outside of the external housing 20 from the side wall 23 and the second wall 22 of the external housing 20.

[0081] In this case, it is preferable that the thermal conductivity of the external housing 20 is set lower than that of the first TIM material 41 and the second TIM material 42 and higher than that of the heat insulating sheet 50. This makes it possible to suppress heat conduction to the first wall 21 through the side wall 23 while realizing heat dissipation from the second wall 22 and the side wall 23, thereby suppressing a temperature rise in the first wall 21.

[0082] As described above, the wireless power transmitting device 10 conducts heat generated in the power semiconductor element 120 to the magnetic sheet 30 via the first heat path HP1, and suppresses the local temperature on the first wall 21 side by thermal diffusion in the magnetic sheet 30.

[0083] The wireless power transmitter 10 conducts heat generated in the power semiconductor element 120 to the second wall 22 via the second heat path HP2, and radiates the heat from the second wall 22 to the outside of the external housing 20, thereby suppressing heat generation.

[0084] The wireless power transmitter 10 insulates the heat that has reached the first heat path HP1 from the first wall 21 side via the third heat path HP3, thereby suppressing heat generation in the living body.

[0085] Furthermore, the wireless power transmitter 10 more reliably forms an electromagnetic field coupling resonance field (see the dotted arrow in FIG. 2 ) through electromagnetic field coupling using the electromagnetic field resonance phenomenon, due to the magnetic path created by the arrangement of the power transmission coil 131 and the magnetic sheet 30. This increases the power efficiency of the wireless power transmitter 10 in electromagnetic field resonance wireless power feeding operation. Therefore, the wireless power transmitter 10 suppresses heat generation due to power loss.

[0086] As described above, the wireless power transmission device 10 can suppress the effects of heat generation on living organisms by temperature control of thermal conduction, thermal diffusion, thermal radiation, and insulation via the first thermal path HP1, the second thermal path HP2, and the third thermal path HP3, and can also achieve high power supply efficiency.

[0087] Second Embodiment A wireless power transmission device according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 5 is a side cross-sectional view showing the configuration of the wireless power transmission device according to the second embodiment.

[0088] 5 , the wireless power transmitter 10A according to the second embodiment differs from the wireless power transmitter 10 according to the first embodiment in that it includes a first TIM material 41A and a gap 500. The other configuration of the wireless power transmitter 10A according to the second embodiment is similar to that of the wireless power transmitter 10 according to the first embodiment, and a description of similar parts will be omitted.

[0089] In the wireless power transmitter 10A, the first TIM material 41A has approximately the same area as the power transmitting circuit board 129. The first TIM material 41A is disposed over the entire surface of the power transmitting circuit board 129 where the magnetic sheet 30 overlaps.

[0090] In this case, it is preferable that the first TIM material 41A also abuts against heat-generating electronic circuit components mounted on the power transmission circuit board 129 other than the power semiconductor element 120. This allows the wireless power transmitter 10A to improve the overall heat dissipation effect of the power transmission circuit board 129 via the first heat path HP1.

[0091] The wireless power transmitter 10A has a gap 500 between the power transmitting coil 131 and the inner surface 212 of the first wall 21. The gap 500 is an air layer of a predetermined thickness, and therefore has low thermal conductivity. Therefore, the gap 500 can achieve the same heat insulating function as the heat insulating sheet 50.

[0092] With this configuration, the wireless power transmitter 10A achieves the same effects as the wireless power transmitter 10.

[0093] Note that the wireless power transmitter 10A may adopt either the configuration including the large-area first TIM material 41A or the configuration including the voids 500. For example, the wireless power transmitter 10A may have a configuration including the voids 500 and the first TIM material 41 according to the first embodiment, or may have a configuration including the first TIM material 41A and the heat insulating sheet 50 according to the first embodiment.

[0094] [Third embodiment] A wireless power transmission device according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 6 is a side cross-sectional view showing the configuration of the wireless power transmission device according to the third embodiment.

[0095] 6 , the wireless power transmitter 10B according to the third embodiment differs from the wireless power transmitter 10 according to the first embodiment in the position of the heat insulating sheet 50. Other configurations of the wireless power transmitter 10B according to the third embodiment are similar to those of the wireless power transmitter 10 according to the first embodiment, and a description of similar parts will be omitted.

[0096] The heat insulating sheet 50 is disposed in contact with the outer surface 211 of the first wall 21 of the extracorporeal housing 20B. The heat insulating sheet 50 is disposed so as to overlap the entire surface of the power transmission coil 131 in plan view, and is disposed over substantially the entire surface of the outer surface 211 of the first wall 21.

[0097] The power transmitting coil 131 abuts against the inner surface 212 of the first wall 21 .

[0098] With this configuration, the wireless power transmitter 10B achieves the same effects as the wireless power transmitter 10. Furthermore, even if the wireless power transmitter 10B comes into contact with the surface of a living body, the heat insulating sheet 50 comes into direct contact with the surface of the living body. This allows the wireless power transmitter 10B to more reliably suppress heat generation in the living body.

[0099] The wireless power transmitter 10B may have a gap between the power transmitting coil 131 and the inner surface 212 of the first wall 21. This further improves the heat insulating effect on the living body side. In this case, it is preferable that the thickness of the gap is small (for example, smaller than the thickness of the heat insulating sheet 50). This allows the distance between the power transmitting coil 131 and the power receiving coil 92 to be as short as possible while improving the heat insulating effect.

[0100] [Fourth embodiment] A wireless power transmission device according to a fourth embodiment of the present invention will be described with reference to the drawings. Fig. 7 is a side cross-sectional view showing the configuration of the wireless power transmission device according to the fourth embodiment.

[0101] 7 , a wireless power transmitter 10C according to the fourth embodiment differs from the wireless power transmitter 10 according to the first embodiment in that the mounting surface 1291 and the back surface 1292 of the power transmission circuit board 129 are reversed. Other configurations of the wireless power transmitter 10C according to the fourth embodiment are the same as those of the wireless power transmitter 10 according to the first embodiment, and a description of similar parts will be omitted.

[0102] The power transmitting circuit board 129 is disposed so that the mounting surface 1291 faces the second wall 22. In other words, the back surface 1292 of the power transmitting circuit board 129 faces the first wall 21.

[0103] The first TIM material 41 abuts against the rear surface 1292 of the power transmission circuit board 129. At this time, the first TIM material 41 is disposed so as to overlap the power semiconductor element 120 in plan view.

[0104] The first TIM material 41A as shown in the second embodiment may be used instead of the first TIM material 41. In this case, the first TIM material 41A abuts on substantially the entire back surface 1292.

[0105] The second TIM material 42 abuts the power semiconductor element 120 .

[0106] With this configuration, the wireless power transmitter 10C achieves the same effects as the wireless power transmitter 10. Furthermore, in the wireless power transmitter 10C, a power transmission circuit board 129 is inserted between the power semiconductor element 120, which is a heat source, and the first wall 21 (living body side). This allows the wireless power transmitter 10C to further suppress heat conduction toward the first wall 21 side.

[0107] Fifth Embodiment A wireless power transmission device according to a fifth embodiment of the present invention will be described with reference to the drawings. Fig. 8 is a side cross-sectional view showing the configuration of the wireless power transmission device according to the fifth embodiment.

[0108] 8 , a wireless power transmitter 10D according to the fifth embodiment differs from the wireless power transmitter 10 according to the first embodiment in that it includes an extracorporeal housing 20D. Other configurations of the wireless power transmitter 10D according to the fifth embodiment are similar to those of the wireless power transmitter 10 according to the first embodiment, and a description of similar parts will be omitted.

[0109] The extracorporeal housing 20D includes a first wall 21, a second wall 22D, and a side wall 23D. The first wall 21 is made of insulating resin that allows an electromagnetic field to pass through. The second wall 22D and the side wall 23D are made of metal.

[0110] With this configuration, wireless power transmitter 10D achieves the same effects as wireless power transmitter 10. Furthermore, in wireless power transmitter 10D, second wall 22D and side wall 23D are made of metal, and therefore have high thermal conductivity. Therefore, wireless power transmitter 10D can achieve a higher heat dissipation effect while achieving wireless power feeding.

[0111] Although the second wall 22D and the side wall 23D of the wireless power transmitter 10D are made of metal, the second wall 22D may be made of metal and the side wall 23D may be made of insulating resin.Furthermore, the side wall 23D facing the second wall 22D may be made of metal and the side wall 23D facing the first wall 21 may be made of insulating resin.

[0112] Sixth Embodiment A wireless power transmission device according to a sixth embodiment of the present invention will be described with reference to the drawings. Fig. 9 is a side cross-sectional view showing the configuration of the wireless power transmission device according to the sixth embodiment.

[0113] 9 , a wireless power transmitter 10E according to the sixth embodiment differs from the wireless power transmitter 10 according to the first embodiment in that it includes a first TIM material 41E. Other configurations of the wireless power transmitter 10E according to the sixth embodiment are similar to those of the wireless power transmitter 10 according to the first embodiment, and a description of similar parts will be omitted.

[0114] The first TIM material 41E has a three-dimensional shape in which the area of ​​the surface that contacts the magnetic sheet 30 is larger than the area of ​​the surface that contacts the power semiconductor element 120.

[0115] With this configuration, the wireless power transmitter 10E achieves the same effects as the wireless power transmitter 10. Furthermore, the wireless power transmitter 10E makes it easier to achieve heat diffusion in the magnetic sheet 30 when heat is conducted from the power semiconductor element 120 to the magnetic sheet 30.

[0116] The configurations of the above-described embodiments can be combined as appropriate, and effects according to each combination can be achieved.

[0117] <1> An extracorporeal casing comprising: an extracorporeal casing having a first wall facing a living body and a second wall facing away from the living body; a power transmitting coil arranged in the extracorporeal casing; a power transmitting resonant capacitor forming a resonant circuit together with the power transmitting coil; a magnetic sheet arranged in the extracorporeal casing; and a power transmitting circuit board arranged in the extracorporeal casing and having mounted thereon a power semiconductor element that handles a DC power source, wherein the power transmitting coil, the magnetic sheet, and the power transmitting circuit board are arranged in this order from the first wall to the second wall, and the power transmitting circuit board has a mounting surface for the power semiconductor element facing the magnetic sheet, a first TIM material arranged between the power semiconductor element and the magnetic sheet and in contact with the power semiconductor element and the magnetic sheet, a second TIM material arranged between the power transmitting circuit board and the second wall and in contact with the power transmitting circuit board and the second wall, and a heat insulating sheet arranged closer to the first wall than the power transmitting coil, or a gap between the power transmitting coil and the first wall. a first heat path passing through the first TIM material and having a first average thermal resistance; a second heat path passing through the second TIM material and having a second average thermal resistance; a third heat path including the heat insulating sheet or the gap and having a third average thermal resistance, the third average thermal resistance being greater than the first average thermal resistance and the second average thermal resistance; heat generated in the power semiconductor element is thermally conducted to the magnetic sheet via the first heat path, and a local temperature on the first wall side is suppressed by thermal diffusion in the magnetic sheet; heat generated in the power semiconductor element is thermally conducted to the second wall via the second heat path, and heat is radiated from the second wall to the outside of the extracorporeal casing, and heat generation is suppressed; heat that has reached the first heat path is insulated from the first wall side by the third heat path, and heat generation in a living body is suppressed; power efficiency is increased in electromagnetic resonance wireless power feeding operation by electromagnetic field coupling using an electromagnetic resonance phenomenon by a magnetic path formed by the arrangement of the power transmitting coil and the magnetic sheet, and heat generation due to power loss is suppressed; A wireless power transmission device that suppresses the effects of heat generation on a living body by a temperature management structure of thermal conduction, thermal diffusion, thermal radiation, and thermal insulation by the first thermal path, the second thermal path, and the third thermal path.

[0118] <2> An extracorporeal casing comprising: an extracorporeal casing having a first wall facing a living body and a second wall facing away from the living body; a power transmitting coil disposed within the extracorporeal casing; a power transmitting resonant capacitor forming a resonant circuit together with the power transmitting coil; a magnetic sheet disposed within the extracorporeal casing; and a power transmitting circuit board disposed within the extracorporeal casing and having a power semiconductor element that handles DC power mounted thereon, wherein the power transmitting coil, the magnetic sheet, and the power transmitting circuit board are disposed in this order from the first wall toward the second wall, and the mounting surface of the power semiconductor element of the power transmitting circuit board faces the second wall, a first TIM material disposed between the power transmitting circuit board and the magnetic sheet and in contact with the power transmitting circuit board and the magnetic sheet, a second TIM material disposed between the power semiconductor element and the second wall and in contact with the power semiconductor element and the second wall, and a heat insulating sheet disposed closer to the first wall than the power transmitting coil, or a gap between the power transmitting coil and the first wall. a first heat path passing through the first TIM material and having a first average thermal resistance; a second heat path passing through the second TIM material and having a second average thermal resistance; a third heat path including the heat insulating sheet or the gap and having a third average thermal resistance, the third average thermal resistance being greater than the first average thermal resistance and the second average thermal resistance; heat generated in the power semiconductor element is thermally conducted to the magnetic sheet via the first heat path, and a local temperature on the first wall side is suppressed by thermal diffusion in the magnetic sheet; heat generated in the power semiconductor element is thermally conducted to the second wall via the second heat path, and heat is radiated from the second wall to the outside of the extracorporeal casing, and heat generation is suppressed; heat that has reached the first heat path is insulated from the first wall side by the third heat path, and heat generation in a living body is suppressed; power efficiency is increased in electromagnetic resonance wireless power feeding operation by electromagnetic field coupling using an electromagnetic resonance phenomenon by a magnetic path formed by the arrangement of the power transmitting coil and the magnetic sheet, and heat generation due to power loss is suppressed; A wireless power transmission device that suppresses the effects of heat generation on a living body by a temperature management structure of thermal conduction, thermal diffusion, thermal radiation, and thermal insulation by the first thermal path, the second thermal path, and the third thermal path.

[0119] <3> The wireless power transmitting device according to <1> or <2>, wherein the thermal conductivity of the first TIM material and the thermal conductivity of the second TIM material are 2.0 W / m·k or more.

[0120] <4> The wireless power transmitting device according to any one of <1> to <3>, wherein the thermal conductivity of the heat insulating sheet is 0.03 W / m·k or less.

[0121] <5> The wireless power transmitting device according to any one of <1> to <4>, wherein the first wall has a lower thermal conductivity than the second wall.

[0122] <6> The wireless power transmitting device according to <5>, wherein the first wall is made of an insulating resin, and the second wall is made of a metal.

[0123] <7> The wireless power transmitting device according to any one of <1> to <6>, wherein the operating frequency band of the power semiconductor element is the 6.78 MHz band or the 13.56 MHz band.

[0124] <8> The wireless power transmitting device according to any one of <1> to <7>, wherein the first TIM material is disposed over the entire surface of the power transmitting circuit board facing the magnetic sheet, the surface being overlaid with the magnetic sheet.

[0125] <9> The wireless power transmitting device according to any one of <1> to <8>, wherein the second TIM material is disposed over the entire surface of the power transmitting circuit board on the second wall side.

[0126] <10> The wireless power transmitting device according to any one of <1> to <9>, wherein, when the heat insulating sheet is used, the heat insulating sheet is disposed inside the extracorporeal housing.

[0127] <11> The wireless power transmitting device according to any one of <1> to <10>, wherein, when the heat insulating sheet is used, the heat insulating sheet is disposed on an outer surface of the first wall.

[0128] 1: Wireless power supply system 10, 10A, 10B, 10C, 10D, 10E: Wireless power transmitter 12: Power transmission circuit 13: Power transmission resonant circuit 20, 20B, 20D: Extracorporeal housing 21: First wall 22, 22D: Second wall 23, 23D: Side wall 29: Ceiling 30: Magnetic sheet 41, 41A, 41E: First TIM material 42: Second TIM material 50: Heat insulating sheet 90: Wireless power receiver 91: Housing 92: Power receiving coil 93: Power receiving side magnetic sheet 120: Power semiconductor element 128: Electronic circuit component 129: Power transmission circuit board 131: Power transmission coil 132: Power transmission resonant capacitor 139: Wiring pattern 200: Internal space 211, 221: Outer surface 212, 222: Inner surface 290: Power supply wiring cable 500: Air gap 901: Power receiving resonance circuit 902: Power receiving resonance capacitor 911: Window member 991: Power receiving circuit 992: Load circuit 1291: Mounting surface 1292: Back surface 1310: Ring conductor HP1: First heat path HP2: Second heat path HP3: Third heat path

Claims

1. An external housing having a first wall on the side facing the living body and a second wall on the side opposite the living body, A power transmission coil arranged inside the external housing, The power transmission coil and the power transmission resonant capacitor that constitute the resonant circuit, A magnetic sheet disposed inside the external housing, A power transmission circuit board, which is placed inside the external housing and on which power semiconductor elements that handle DC power are mounted, Equipped with, The power transmission coil, the magnetic sheet, and the power transmission circuit board are arranged in that order from the first wall toward the second wall. The power transmission circuit board has a mounting surface for the power semiconductor elements facing the magnetic sheet. A first TIM material is disposed between the power semiconductor element and the magnetic sheet and is in contact with the power semiconductor element and the magnetic sheet, A second TIM material is disposed between the power transmission circuit board and the second wall and is in contact with the power transmission circuit board and the second wall, An insulating sheet positioned on the first wall side of the power transmission coil, or the gap between the power transmission coil and the first wall, Equipped with, A first heat path having a first average thermal resistance is formed by passing through the first TIM material. A second heat path having a second average thermal resistance is formed by passing through the second TIM material. The insulating sheet or the void forms a third heat path having a third average thermal resistance, The third average thermal resistance is greater than the first average thermal resistance and the second average thermal resistance. The heat generated in the power semiconductor element is conducted to the magnetic sheet by the first heat path, and the local temperature on the first wall side is suppressed by heat diffusion in the magnetic sheet. The heat generated in the power semiconductor element is conducted to the second wall by the second heat path, and the heat is radiated from the second wall to the outside of the external housing to suppress heat generation. The heat that reaches the first heat path is insulated from the first wall side by the third heat path, thereby suppressing heat transfer to the living body. The magnetic path formed by the arrangement of the power transmission coil and the magnetic sheet increases the power efficiency in electromagnetic field resonance wireless power transfer operation using electromagnetic field coupling based on the electromagnetic field resonance phenomenon, thereby suppressing heat generation due to power loss. The temperature control structure, comprising heat conduction, heat diffusion, heat radiation, and thermal insulation through the first, second, and third heat paths, suppresses the effects of heat generation on living organisms. Wireless power transmission device.

2. An external housing having a first wall on the side facing the living body and a second wall on the side opposite the living body, A power transmission coil arranged inside the external housing, The power transmission coil and the power transmission resonant capacitor that constitute the resonant circuit, A magnetic sheet disposed inside the external housing, A power transmission circuit board is placed inside the external housing and has power semiconductor elements that handle DC power mounted on it, Equipped with, The power transmission coil, the magnetic sheet, and the power transmission circuit board are arranged in that order from the first wall toward the second wall. The power transmission circuit board has a mounting surface for the power semiconductor elements facing the second wall, A first TIM material is disposed between the power transmission circuit board and the magnetic sheet and is in contact with the power transmission circuit board and the magnetic sheet, A second TIM material is disposed between the power semiconductor element and the second wall and is in contact with the power semiconductor element and the second wall, An insulating sheet positioned on the first wall side of the power transmission coil, or the gap between the power transmission coil and the first wall, Equipped with, A first heat path having a first average thermal resistance is formed by passing through the first TIM material. A second heat path having a second average thermal resistance is formed by passing through the second TIM material. The insulating sheet or the void forms a third heat path having a third average thermal resistance, The third average thermal resistance is greater than the first average thermal resistance and the second average thermal resistance. The heat generated in the power semiconductor element is conducted to the magnetic sheet by the first heat path, and the local temperature on the first wall side is suppressed by heat diffusion in the magnetic sheet. The heat generated in the power semiconductor element is conducted to the second wall by the second heat path, and the heat is radiated from the second wall to the outside of the external housing to suppress heat generation. The heat that reaches the first heat path is insulated from the first wall side by the third heat path, thereby suppressing heat transfer to the living body. The magnetic path formed by the arrangement of the power transmission coil and the magnetic sheet increases the power efficiency in electromagnetic field resonance wireless power transfer operation using electromagnetic field coupling based on the electromagnetic field resonance phenomenon, thereby suppressing heat generation due to power loss. The temperature control structure, comprising heat conduction, heat diffusion, heat radiation, and thermal insulation through the first, second, and third heat paths, suppresses the effects of heat generation on living organisms. Wireless power transmission device.

3. The thermal conductivity of the first TIM material and the thermal conductivity of the second TIM material are 2.0 W / m·k or higher. A wireless power transmission device according to claim 1 or claim 2.

4. The thermal conductivity of the aforementioned insulation sheet is 0.03 W / m·K or less. A wireless power transmission device according to claim 1 or claim 2.

5. The thermal conductivity of the first wall is lower than that of the second wall. A wireless power transmission device according to claim 1 or claim 2.

6. The first wall is made of an insulating resin, The aforementioned second wall is made of metal. The wireless power transmission device according to claim 5.

7. The operating frequency band of the power semiconductor element is either 6.78 MHz or 13.56 MHz. A wireless power transmission device according to claim 1 or claim 2.

8. The first TIM material is arranged over the entire surface of the magnetic sheet on the magnetic sheet side of the power transmission circuit board where the magnetic sheets overlap. A wireless power transmission device according to claim 1 or claim 2.

9. The second TIM material is arranged across the entire surface of the second wall-side surface of the power transmission circuit board. A wireless power transmission device according to claim 1 or claim 2.

10. When the aforementioned heat insulating sheet is used, the heat insulating sheet is placed inside the external housing. A wireless power transmission device according to claim 1 or claim 2.

11. When the aforementioned heat insulating sheet is used, the heat insulating sheet is placed on the outer surface of the first wall. A wireless power transmission device according to claim 1 or claim 2.