Patent ID: 12205740

DESCRIPTION OF EMBODIMENTS

Hereinafter, a planar coil and a transformer, a wireless electric power transmission device, and an electromagnet that include it, in the present disclosure, will be explained in detail, with reference to the drawings.

As illustrated inFIG.1andFIG.2, a planar coil10in the present disclosure has a substrate1that has a first surface1a. Furthermore, the planar coil10includes a first metal layer2athat is positioned on the first surface1a. Furthermore, the first metal layer2ahas a plurality of voids9.

Herein, the substrate1in the planar coil10in the present disclosure is composed of a ceramic(s). For a ceramic(s), it is possible to provide, for example, an aluminum-oxide-based ceramic(s), a silicon-carbide-based ceramic(s), a cordierite-based ceramic(s), a silicon-nitride-based ceramic(s), an aluminum-nitride-based ceramic(s), a mullite-based ceramic(s), or the like. Herein, if the substrate1is composed of an aluminum-oxide-based ceramic(s), it is excellent in processability thereof and is inexpensive.

Herein, for example, an aluminum-oxide-based ceramic(s) contain(s) 70% by mass or more of aluminum oxide among 100% by mass of all components that compose the ceramic(s). Then, it is possible to confirm a material of the substrate1in the planar coil10in the present disclosure according to an undermentioned method. First, the substrate1is measured by using an X-ray diffractometer (XRD) and identification thereof is executed based on an obtained 2θ (where 2θ is a diffraction angle) by using a JCPDS card. Then, quantitative analysis of a contained component(s) is executed by using an X-ray fluorescence analyzer (XRF). Then, for example, if presence of aluminum oxide is confirmed by identification as described above and a content of aluminum oxide (Al2O3) that is converted from a content of aluminum (Al) that is measured by an XRF is 70% by mass or more, it is an aluminum-oxide-based ceramic(s). Additionally, it is also possible to confirm another/other ceramic(s) according to an identical method.

Furthermore, a thermal expansion coefficient(s) of a ceramic(s) is/are generally about 7.2 ppm for an aluminum-oxide-based ceramic(s), about 3.7 ppm for a silicon-carbide-based ceramic(s), about 1.5 ppm for a cordierite-based ceramic(s), about 2.8 ppm for a silicon-nitride-based ceramic(s), about 4.6 ppm for an aluminum-nitride-based ceramic(s), or about 5.0 ppm for a mullite-based ceramic(s).

Furthermore, as illustrated inFIG.1, the substrate1may be of a plate shape. The substrate1may have the first surface1aand a second surface1bthat is positioned on an opposite side of the first surface1a. Furthermore, the first metal layer2amay be positioned on the first surface1aof the substrate1in any arrangement. Furthermore, although the substrate1inFIG.1has a through-hole3that penetrates from a side of the first surface1ato a side of the second surface1b, the through-hole3is not an essential component. Additionally, such a through-hole3is a hole for inserting a magnetic material.

As illustrated inFIG.3andFIG.10, a first metal layer2ahas a void9. Hence, a surface area of the first metal layer2ais greater than that of a metal layer where the void9is absent. Therefore, a planar coil10has a high heat release property.

Furthermore, as illustrated inFIG.3andFIG.10, the first metal layer2amay have a first metal particle4aand a second metal particle4b. The void9may be positioned between the first metal particle4aand the second metal particle4b. In a case where such a configuration is possessed thereby, heat that is generated in the first metal particle4aand the second metal particle4bis absorbed by the void9, so that the planar coil10has a high heat release property.

Herein, a material(s) of the first metal particle4aand the second metal particle4bthat compose the first metal layer2amay be, for example, a stainless one or copper.

Furthermore, as illustrated inFIG.3andFIG.10, a shape(s) of the first metal particle4aand the second metal particle4bmay be, for example, a spherical shape(s), a granular shape(s), a whisker shape(s), or a needle shape(s). In a case where the first metal particle4aand the second metal particle4bare of a whisker shape(s) or a needle shape(s), the first metal particle4aand the second metal particle4bmay be bent. The first metal particle4aand the second metal particle4bmay have a corner part(s). Furthermore, in a case where the first metal particle4aand the second metal particle4bare of a spherical shape(s) or a granular shape(s), a length(s) of the first metal particle4aand the second metal particle4bin a longitudinal direction(s) thereof may be 0.5 μm or greater and 200 μm or less. In a case where the first metal particle4aand the second metal particle4bare of a whisker shape(s) or a needle shape(s), a diameter(s) thereof may be 1 μm or greater and 100 μm or less, and a length(s) thereof may be 100 μm or greater and 5 mm or less.

InFIG.3, the first metal particle4aand the second metal particle4bare of granular shapes. InFIG.10, the first metal particle4aand the second metal particle4bare of whisker shapes. Furthermore, an average thickness of the first metal layer2amay be 1 μm or greater and 5 mm or less.

Furthermore, a porosity of the first metal layer2amay be, for example, 10% or greater and 90% or less. A porosity is provided as an index that indicates a proportion of the void9that is occupied in the first metal layer2a. Herein, it is sufficient that a porosity of the first metal layer2ais measured and calculated by using, for example, an Archimedian method.

Furthermore, as illustrated inFIG.3andFIG.10, the first metal layer2amay have a third metal particle4c. The first metal layer2amay have a weld part between the first metal particle4aand the third metal particle4c. The first metal particle4aand the third metal particle4cdo not simply contact but are welded, so that heat readily transfers between the first metal particle4aand the third metal particle4c. Hence, the first metal layer2ahas a high efficiency of heat conduction as a whole. Therefore, the planar coil10has high reliability.

Furthermore, the first metal layer2ain the planar coil10in the present disclosure may have a resin between the first metal particle4aand the second metal particle4b. If such a configuration is satisfied, it is possible for a resin to absorb stress at a time when the first metal particle4aand the second metal particle4bexpand.

Herein, a resin material may be, for example, a silicone resin. If a resin is a silicone resin, it is elastic as compared with another resin (such as an epoxy resin), so that it is possible to effectively absorb stress at a time when the first metal particle4aand the second metal particle4bexpand and a crack is not readily generated in a substrate1even over a long period of use.

Furthermore, as illustrated inFIG.3, the planar coil10in the present disclosure may include a bonding layer5that is positioned between the first metal layer2aand a first surface1a. If such a configuration is satisfied, the first metal layer2ais not readily released from the substrate1, and the bonding layer5relaxes stress that is generated due to a thermal expansion difference therebetween, so that a crack is not readily generated in the substrate1. Hence, it is possible to execute a longer period of use. Additionally, an average thickness of the bonding layer5may be, for example, 1 μm or greater and 0.5 mm or less.

Furthermore, the bonding layer5in the planar coil10in the present disclosure may be composed of one that is selected from a resin, a metal, and a glass. Herein, for a resin, it is possible to provide, for example, silicone, imidamide, or the like. For a metal, it is possible to provide, for example, nickel, platinum, copper, or the like. For a glass, it is possible to provide, for example, a borosilicate-type glass, a silicate-type glass, or the like. In a case where the bonding layer5includes a material as described above, the first metal layer2aand the substrate1are bonded tightly, so that the first metal layer2ais not readily released from the substrate1.

Herein, if the bonding layer5is composed of a glass, stress that is caused by a thermal expansion difference between the first metal layer2aand the substrate1is effectively relaxed by the bonding layer5because a thermal expansion coefficient of a glass is intermediate between a metal and a ceramic(s), so that a crack is not readily generated in the substrate1. Moreover, if a specific permittivity of a glass that composes the bonding layer5is 2 or greater and 10 or less, it is also possible to relax concentration of electric field.

Alternatively, the bonding layer5in the planar coil10in the present disclosure may be composed of a porous ceramic(s). Herein, it is sufficient that a porous ceramic(s) is/are, for example, a component(s) that is/are identical to a ceramic(s) that compose(s) the substrate1. If such a configuration is satisfied, the first metal particle4aand the second metal particle4bthat compose the first metal layer2apenetrate into an inside of the bonding layer5that is porous, so that the first metal layer2aand the bonding layer5are bonded tightly, and both the substrate1and the bonding layer5are of a ceramic(s), so that the substrate1and the bonding layer5are bonded tightly. Hence, the first metal layer2ais not readily released from the substrate1.

Furthermore,FIG.11is an example of a cross-sectional view ofFIG.1along line A-A′ therein. A substrate1in a planar coil10in the present disclosure may have a flow channel11in an inside thereof. If such a configuration is satisfied, a fluid flows through the flow channel11of the substrate1, so that it is possible to execute temperature adjustment of a first metal layer2a.

Furthermore, as illustrated inFIG.4toFIG.6, a planar coil10in the present disclosure may further include a second metal layer2band a connection conductor6where the second metal layer2bmay be positioned on a second surface1band a first metal layer2aand the second metal layer2bmay be electrically connected through the connection conductor6. If such a configuration is satisfied, the first metal layer2a, the connection conductor6, and the second metal layer2bare provided as a single metal layer, so that it is possible to increase a length of a metal layer on a limited surface of a substrate1.

Herein, the second metal layer2bmay have a plurality of voids9similarly to the first metal layer2a. Furthermore, the first metal layer2amay have a first metal particle4aand a second metal particle4b. A void9may be positioned between the first metal particle4aand the second metal particle4b. Furthermore, a bonding layer5as described above may be positioned between the second metal layer2band the second surface1b.

Furthermore, although it is sufficient that a material that composes the connection conductor6is a metal, it may be a metal(s) that is/are identical to that/those of the first metal particle4aand the second metal particle4bthat compose the first metal layer2aand the second metal layer2b. Furthermore, the connection conductor6may have a plurality of voids9similarly to the first metal layer2aand the second metal layer2b. Furthermore, the first metal layer2amay have the first metal particle4aand the second metal particle4b. The void9may be positioned between the first metal particle4aand the second metal particle4b.

Additionally, although the connection conductor6may be of any shape, a diameter thereof may be 0.3 mm or greater and 2 mm or less if it is of a circularly cylindrical shape. Furthermore, although it is sufficient that a number of a connection conductor(s)6is one or more, a number of the connection conductor(s)6may be increased depending on a magnitude of an electric current that is used.

Furthermore,FIG.5illustrates an example where the connection conductor6is positioned in an inside of the substrate1, and if such a configuration is provided, the connection conductor6is free from a risk of being damaged in a case where a plurality of planar coils10are laminated so as to provide a laminated coil.

Furthermore, as illustrated inFIG.7andFIG.8, a substrate1in a planar coil10in the present disclosure may have a protrusion part7that protrudes from a first surface1a. Herein, as illustrated inFIG.7, a height of the protrusion part7is greater than a height of a first metal layer2a. If such a configuration is satisfied, the protrusion part7contacts a substrate1of another laminated planar coil10in a case where a plurality of planar coils10are laminated so as to provide a laminated coil, so that it is possible to execute lamination thereof without damaging the first metal layer2a.

Additionally, the substrate1may have a protrusion part7that protrudes from a second surface1bin a case where a second metal layer2bis present.

Furthermore, as illustrated inFIG.7, the protrusion part7in the planar coil10in the present disclosure may be positioned around the first metal layer2athat is positioned on the first surface1a. Herein,FIG.7illustrates an example where the substrate1has a protrusion part7aand a protrusion part7bthat are of a frame shapes in a plan view thereof and the first metal layer2ais positioned in a region that is surrounded by such a protrusion part7aand a protrusion part7b. If such a configuration is satisfied, it is possible to laminate the plurality of planar coils10stably without damaging the first metal layer2a.

Furthermore, as illustrated inFIG.9, a protrusion part7in a planar coil10in the present disclosure may have a hole8that penetrates the protrusion part7in a thickness direction thereof. If such a configuration is satisfied, it is possible to pour a gas through a hole of the protrusion part7, so that it is possible to readily cool a first metal layer2a.

Furthermore, as illustrated inFIGS.12A,FIG.12B,FIG.12C, andFIG.12D, a planar coil10in the present disclosure may be included in a transformer100. The transformer100includes one or more planar coils10on an electric power supply side or an electric power receipt side thereof, and an electric current(s) flow(s) through a first metal layer(s)2a, so that it is possible to provide the transformer100that converts an electric voltage. As illustrated inFIG.12AandFIG.12B, the transformer100may include the planar coil10on an electric power supply side thereof. Furthermore, the transformer100may include a planar coil20on an electric power receipt side thereof. An external electric power source is connected to the planar coil10and an electric current flows through a first metal layer2a, so that electromagnetic induction is caused. Hence, an electric current flows through a first metal layer2aof the planar coil20. As illustrated inFIG.12CandFIG.12D, a number of a turn(s) of the first metal layer2ain the planar coil10may be different from a number of a turn(s) of the first metal layer2ain the planar coil20. Numbers of a turn(s) of the planar coil10and the planar coil20are adjusted, so that it is possible to change an electric voltage.

Furthermore, as illustrated inFIGS.13A,FIG.13B, andFIG.13C, a planar coil10in the present disclosure may be included in a wireless electric power transmission device200. The wireless electric power transmission device200may include one or more planar coils10on an electric power supply side or an electric power receipt side thereof. In such a case, an electric current(s) flow(s) through a first metal layer(s)2a, so that it is possible to transmit an electric power. Hence, it is possible to use the planar coil10and a planar coil20in the present disclosure as the wireless electric power transmission device200. The wireless electric power transmission device200inFIG.13AandFIG.13Bmay include the planar coil10on an electric power supply side thereof and the planar coil20on an electric power receipt side thereof. An external electric power source is connected to the planar coil10and an electric current flows through a first metal layer2a, so that electromagnetic induction is caused. Hence, an electric current flows through the first metal layer2aof the planar coil20. Thus, it is possible to use the planar coil20in the present disclosure as the wireless electric power transmission device200that executes delivery of an electric power.

Furthermore, as illustrated inFIG.14, a planar coil10in the present disclosure may be included in an electromagnet300. The electromagnet300may have a through-hole3. The electromagnet300may have a magnetic core13in the though-hole3. The electromagnet300includes one or more planar coils10and an electric current(s) flow(s) through a first metal layer(s)2a, so that magnetic force is generated at the magnetic core13. Hence, it is possible to use the planar coil10in the present disclosure as an electromagnet. Additionally, it is sufficient that a material of a magnetic core is a magnetic material, and it is possible to provide, for example, ferrite, iron, ferrosilicon, an iron-nickel-based alloy, and an iron-cobalt-based alloy. For an example of an iron-nickel-based alloy, it is possible to provide permalloy. Furthermore, for an example of an iron-cobalt-based alloy, it is possible to provide permendur.

Next, an example of a manufacturing method for a planar coil in the present disclosure will be explained.

First, a sintering aid, a binder, a solvent, and the like are added and appropriately mixed to a powder of a raw material (such as aluminum oxide or silicon nitride) that is provided as a main component so as to fabricate a slurry. Then, a green sheet is formed by using such a slurry according to a doctor blade method and punching by a die and/or laser processing is applied thereto, so as to provide a green sheet with a desired shape. Alternatively, such a slurry is sprayed and dried so as to obtain a granulated granule. Subsequently, such a granule is rolled so as to form a green sheet and punching by a die and/or laser processing is applied thereto, so as to provide a green sheet with a desired shape.

Herein, when punching by a die and/or laser processing is applied thereto, a hole or the like that is provided as a flow channel may be formed in a green sheet.

Then, a plurality of green sheets are laminated so as to obtain a molded body. Herein, a flow channel may be formed or a site that is provided as a protrusion part may be formed. Furthermore, a metal paste that is provided as a connection conductor may be embedded in a molded body.

Then, such a molded body is fired so as to obtain a substrate that is composed of a ceramic(s) and has a first surface.

Then, a first metal layer is formed on a first surface of a substrate. First, a mask with a desired shape that is composed of a porous resin is formed on a first surface. Then, for example, a mixed liquid where a plurality of metal particles that include a first metal particle and a second metal particle that are composed of a stainless one or copper are mixed to a liquid such as water is prepared and is poured into a space that is formed by such a mask. Then, a mixed liquid is dried so as to vaporize a liquid. Subsequently, after a mask is eliminated by burning thereof or use of a solvent and pressurization thereof is executed at a predetermined pressure, a substrate is heated or ultrasonic vibration is applied thereto. Thereby, it is possible to weld a first metal particle and a second metal particle. Thereby, a first metal layer that has a void is obtained. Furthermore, it is possible to form a weld part between a first metal particle and a third metal particle.

Additionally, a bonding layer may first be formed on a first surface of a substrate and a first metal layer may subsequently be formed on such a bonding layer, without directly forming the first metal layer on the first surface. Herein, a bonding layer is of a resin, a metal, a glass, or a porous ceramic(s). In a case where a bonding layer is of a metal, it is sufficient that formation thereof is executed by using a sputtering method after formation of a mask as described above or formation thereof is executed by an electroless plating method and/or a metallization method. On the other hand, in a case where a bonding layer is of a resin, a glass, or a porous ceramic(s), it is sufficient that the bonding layer is formed before formation of a mask as described above. In such a case, it is sufficient that a resin, a glass, or a porous ceramic(s) is/are formed by applying a paste that is provided with it as a main component thereof to a first surface and executing heat treatment thereof. Furthermore, a resin, a glass, or a porous ceramic(s) is/are of an insulation property, so that formation thereof may be executed so as to cover a whole of a first surface of a substrate. Additionally, if a porous ceramic(s) is/are a component(s) that is/are identical to a ceramic(s) that compose(s) a substrate, it/they is/are readily bonded to the substrate.

Then, if a bonding layer is of a resin, a metal, or a glass, a first metal layer is formed on the bonding layer and subsequently a substrate is heated, so that the bonding layer is wetted and thereby bonded to the first metal layer. Furthermore, if a bonding layer is of a porous ceramic(s), a metal particle that composes a first metal layer penetrates into the porous ceramic(s) so as to attain bonding thereof. Additionally, if a bonding layer is of a metal, an electric current flows through the bonding layer and a first metal layer so as to bond a metal of the bonding layer and a metal particle that composes the first metal layer, so that it is also possible to bond the bonding layer and the first metal layer.

Additionally, a substrate that has a first metal layer may be obtained by preparing the first metal layer separately and mounting the first metal layer on a bonding layer that is preliminarily formed on a first surface, or applying a paste that is provided as a bonding layer to the first metal layer, subsequently mounting it on a first surface, and heating the substrate. In such a case, a first metal layer is preliminarily fabricated by an undermentioned method. First, for example, a mixed liquid where a plurality of metal particles that are composed of a stainless one or copper are mixed to a liquid such as water is prepared, and is poured into a mold that is provided with a shape of a first metal layer. Then, this is dried so as to vaporize a liquid. Then, pressurization thereof is executed at a predetermined pressure and heating thereof is executed, or ultrasonic vibration is applied, so that a first metal particle and a second metal particle are bonded. Then, if removal thereof from a mold is executed, a first metal layer is obtained where a plurality of metal particles that include a first metal particle and a second metal particle are bonded and it has a void.

Additionally, a first metal layer may be fabricated by an undermentioned method. First, a plurality of metal particles that include a first metal particle and a second metal particle and a binder are mixed, and subsequently, a molded body is fabricated by a mechanical press method. Then, such a molded body is dried so as to vaporize a binder. Subsequently, heating thereof is executed or ultrasonic vibration is applied thereto. Thereby, it is possible to weld a plurality of metal particles that include a first metal particle and a second metal particle together. Thereby, it is possible to form a weld part between a first metal particle and a third metal particle. Thereby, a first metal layer that has a void is obtained.

Furthermore, a second metal layer may be formed on a second surface of a substrate by a method that is identical to that of a first metal layer as described above.

Additionally, the present disclosure is not limited to an embodiment(s) as described above and a variety of modifications, improvements, and/or the like are possible without departing from an essence of the present disclosure.

REFERENCE SIGNS LIST

1: substrate1a: first surface1b: second surface2a: first metal layer2b: second metal layer3: through-hole4a: first metal particle4b: second metal particle4c: third metal particle5: bonding layer6: connection conductor7: protrusion part8: hole9: void10: planar coil11: flow channel12: weld part13: magnetic core