KR101919039B1 - Soft magnetic sheet for antenna of receiving part in wireless power supply system - Google Patents

Abstract

In the embodiment of the present invention, two or more layers of soft magnetic metal ribbons are laminated, an insulating layer is included between the soft magnetic ribbon layers, a magnetic shielding treatment is performed on the side surface of the soft magnetic sheet, The present invention relates to a soft magnetic sheet for a power receiving antenna of a wireless power transmission system capable of minimizing loss of magnetic flux in a thickness direction of a wireless power transmission system. In addition, in the wireless power transmission system, by forming fine cracks and slits in the soft magnetic ribbon, the resistivity is increased to raise the frequency to the near field communications (NFC) band, and the magnetic permeability is efficiently used So that the power transmission efficiency can be increased.

Description

TECHNICAL FIELD [0001] The present invention relates to a soft magnetic sheet for a power receiving unit antenna of a wireless power system,

An embodiment of the present invention relates to a soft magnetic sheet for a power receiving antenna of a wireless power system.

In the 1800s, electric motors and transformers using electromagnetic induction principles began to be used, and then radio waves and lasers were used to transmit the electric energy to the desired devices wirelessly. A method of transmitting electrical energy by radiating the same electromagnetic wave has also been attempted. Our electric toothbrushes and some wireless shavers are actually charged with electromagnetic induction.

Electromagnetic induction is a phenomenon in which a voltage is induced and a current flows when a magnetic field is changed around a conductor. The principle of simply receiving the electromagnetic energy generated around the transmitting antenna while applying the electric energy to the transmitting antenna is converted into the electric energy by receiving the receiving antenna. The transmit and receive antennas show the highest power transmission rates when facing each other at close distances. In this case, the soft magnetic material is used for focusing the electromagnetic energy radiated to the surroundings toward the receiving antenna, so that the receiving antenna can receive more energy. Since the power receiver is included in a smart phone or the like, a thin thickness is required, and a sheet-shaped soft magnetic material is used for miniaturization and thinning. The soft magnetic sheet is also used as a shielding member for the back surface. In order to obtain a sufficient shielding effect, the permeability is large, and as the area and thickness increase, a more effective shielding effect can be obtained.

As such a soft magnetic sheet, a magnetic material such as an amorphous ribbon, a ferrite, or a polymer sheet containing magnetic powder is generally used. The magnetic field focusing effect for enhancing magnetic shielding and additional function is good in the order of amorphous ribbon having high magnetic permeability, ferrite, and polymer sheet containing magnetic powder.

The center of the power transmission section includes permanent magnets irrespective of the implementation of the functions of magnetic induction and self-resonance. The reason why the permanent magnet is installed is to correct the position of the transmitting antenna and the receiving antenna to the optimum position. That is, when the smart phone is placed on the transmission pad provided with the power transmission unit, the smart phone is moved by the force of the permanent magnet in order to set the optimal position. At this time, the center of the receiving antenna of the smartphone may also include a protruding soft magnetic core. If the permanent magnet is placed at the center of the transmitting antenna, the soft magnetic sheet of the receiving part is affected and the magnetic permeability is lowered.

Since the soft magnetic core of the transmitter is thick and has a thickness of about several millimeters, the magnetic permeability of the certain portion adjacent to the permanent magnet is low. However, the soft magnetic sheet having a thickness of about 0.1 mm to 0.3 mm has a high The magnetization value is saturated due to the adjacent permanent magnet. As a result, electromagnetic energy leakage from the transmission antenna and the reception antenna can not be prevented, and the transmission efficiency is lowered.

The embodiments of the present invention are designed to overcome the problems of the prior art as described above, and it is an object of the present invention to provide a soft magnetic metal ribbon having a magnetic permeability of 10 to 500,000, The present invention provides a soft magnetic sheet for a power receiving antenna of a wireless power transmission system including an insulating layer on a side surface of a soft magnetic sheet and a magnetic shielding circuit formed on a side surface of the soft magnetic sheet.

A wireless charging apparatus according to an embodiment of the present invention includes: a plurality of soft magnetic ribbons including an Fe-based soft magnetic alloy; And a plurality of soft magnetic ribbons disposed on the plurality of soft magnetic ribbons, wherein the plurality of soft magnetic ribbons comprise at least one of a lowermost soft magnetic ribbon, an uppermost soft magnetic ribbon, and at least one Wherein at least one of the lowermost soft magnetic ribbon and the top soft magnetic ribbon is located on the outermost side of at least one of the middle layer soft magnetic ribbons Wherein the extension is disposed on a side of the middle layer soft magnetic ribbon to reduce leakage flux that radiates to the side of the middle soft magnetic ribbon.
The middle layer soft magnetic ribbon may include a first middle layer soft magnetic ribbon disposed on the lowermost soft magnetic ribbon and a second middle layer soft magnetic ribbon disposed on the first middle layer soft magnetic ribbon.
The extension may extend from the lowermost soft magnetic ribbon and be disposed on a side of the first middle layer soft magnetic ribbon.
The extension of the lowermost soft magnetic ribbon may be disposed on a side of the second intermediate layer soft magnetic ribbon.
The extension may extend from the lowermost soft magnetic ribbon and be in contact with the top soft magnetic ribbon.
The extension may extend from the top layer soft magnetic ribbon and be disposed on a side of the second middle layer soft magnetic ribbon.
An extension of the uppermost soft magnetic ribbon may be disposed on a side of the first intermediate layer soft magnetic ribbon.
The extension may extend from the topmost soft magnetic ribbon and the top soft magnetic ribbon may contact the bottom soft magnetic ribbon.
An insulating layer may be further disposed on at least one of the bottom soft magnetic ribbon and the at least one middle soft magnetic ribbon and between the at least one middle soft magnetic ribbon and the top soft magnetic ribbon.
At least one of the plurality of soft magnetic ribbons may be cracked.
The Fe-based soft magnetic alloy includes Fe-Si-B based soft magnetic alloy, Fe-Si-Al based soft magnetic alloy, Fe-Hf-C based soft magnetic alloy, Fe-Cu-Nb- Fe-Si-N based soft magnetic alloy, Co-Fe-Si-B based soft magnetic alloy and Co-Fe-Ni-Si-B based soft magnetic alloy.
The extension may be disposed on at least a portion of the side of the middle layer soft magnetic ribbon.
A wireless charging device according to an embodiment of the present invention includes a first soft magnetic ribbon, a second soft magnetic ribbon disposed on the first soft magnetic ribbon, and a third soft magnetic ribbon disposed on the second soft magnetic ribbon. A plurality of soft magnetic ribbons; And a wireless charging coil disposed on the third soft magnetic ribbon, wherein the plurality of soft magnetic ribbons comprises an Fe-based soft magnetic alloy, and wherein between the first soft magnetic ribbon and the second soft magnetic ribbon and between the first soft magnetic ribbon and the second soft magnetic ribbon, Wherein an insulating layer is disposed on at least one of the second soft magnetic ribbon and the third soft magnetic ribbon and the first soft magnetic ribbon is disposed on the outermost side of the second soft magnetic ribbon As shown in Fig.
The plurality of soft magnetic ribbons may further include a fourth soft magnetic ribbon disposed between the second soft magnetic ribbon and the third soft magnetic ribbon.
The first soft magnetic ribbon may be further extended to be disposed on the side of the fourth soft magnetic ribbon.
The first soft magnetic ribbon may be in contact with the third soft magnetic ribbon.
And an insulating layer disposed between the second soft magnetic ribbon and the fourth soft magnetic ribbon.
The Fe-based soft magnetic alloy includes Fe-Si-B based soft magnetic alloy, Fe-Si-Al based soft magnetic alloy, Fe-Hf-C based soft magnetic alloy, Fe-Cu-Nb- Fe-Si-N based soft magnetic alloy, Co-Fe-Si-B based soft magnetic alloy and Co-Fe-Ni-Si-B based soft magnetic alloy.
Each of the first soft magnetic ribbon to the fourth soft magnetic ribbon may have a thickness of 1 탆 to 30 탆.
The thickness of each of the first soft magnetic ribbon to the fourth soft magnetic ribbon may be 15 mu m to 30 mu m.
The thickness of each of the insulating layers may be 1 nm to 30 탆.
The insulating layer may be formed of a resin such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyvinyl chloride, polyvinyl alcohol resin, silicone resin, epoxy resin, acrylate resin, urethane resin, polyamide resin and polyimide resin And the like.
The insulating layer may have a thermal conductivity of 1 W / mK or more.
A crack may be formed on at least one surface of the plurality of soft magnetic ribbons.
A wireless charging device according to an embodiment of the present invention includes a first soft magnetic ribbon, a second soft magnetic ribbon disposed on the first soft magnetic ribbon, and a third soft magnetic ribbon disposed on the second soft magnetic ribbon. A plurality of soft magnetic ribbons; And a wireless charging coil disposed on the third soft magnetic ribbon, wherein the plurality of soft magnetic ribbons comprises an Fe-based soft magnetic alloy, and the first soft magnetic ribbon and the second soft magnetic ribbon Wherein an insulating layer is disposed on at least one of the second soft magnetic ribbon and the third soft magnetic ribbon and the third soft magnetic ribbon is disposed on the side of the second soft magnetic ribbon, And extends further outward than the outer side.
The third soft magnetic ribbon may be disposed on at least a portion of the side of the second soft magnetic ribbon.
The third soft magnetic ribbon may be in contact with the first soft magnetic ribbon.

According to the embodiment, two or more soft magnetic metal ribbons having a relative magnetic permeability of 10 to 500,000 and a thickness of 1 to 30 탆 are stacked, and an insulating layer is included between the soft magnetic ribbon layers, The magnetic shielding process is performed on the power receiving antenna of the wireless power transmission system in which the closed magnetic circuit is formed and the magnetic flux loss in the thickness direction of the soft magnetic sheet is minimized to enhance the power transmission effect. In addition, in the wireless power transmission system, by increasing the specific resistance by forming fine cracks and slits in the soft magnetic ribbon, the frequency is increased from 100 kHz to 200 kHz to the near field communications (NFC) band of 13.56 MHz, Accordingly, it is possible to increase the power transmission efficiency by efficiently using the permeability.

1 is a schematic view of a soft magnetic sheet for a power receiving antenna of a wireless power transmission system according to the present embodiment.
2 is a schematic diagram showing the magnetic flux distribution in the conventional soft magnetic sheet.
3 is a schematic diagram showing the magnetic flux distribution in the soft magnetic sheet according to the present embodiment.
4 is a photograph showing micro-cracks formed on the surface of the soft magnetic ribbon according to this embodiment.
5 is a graph showing the skin depth before and after formation of micro cracks according to the present embodiment.
6 is a schematic view showing a slit formed in the soft magnetic ribbon according to this embodiment.
Fig. 7 is a schematic view of a soft magnetic sheet laminated in such a manner that the magnetization easy axes intersect and perpendicular to each other according to this embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the embodiments described in the present specification and the constitutions shown in the drawings are only a preferred embodiment of the present invention, and that various equivalents and modifications can be made at the time of filing of the present application . DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the subject matter of the present invention. The following terms are defined in consideration of the functions of the present invention, and the meaning of each term should be interpreted based on the contents throughout this specification. The same reference numerals are used for portions having similar functions and functions throughout the drawings.

1 is a schematic diagram of a soft magnetic sheet for a power receiving antenna of a wireless power transmission system according to an embodiment of the present invention.

1, a soft magnetic sheet 100 according to an embodiment of the present invention includes two or more layers of soft magnetic metal ribbons 10, and an insulating layer 20 is interposed between soft magnetic ribbons 10 .

The soft magnetic ribbon 10 may use a thin ribbon of Fe-based or Co-based amorphous alloy or nanocrystalline alloy most suitable for performance and price for wireless power transmission. Examples of the Fe-based amorphous alloy include Fe-Si-B, Fe-Si-Al, Fe-Hf-C, Fe-Cu-Nb-Si- The Co-based amorphous alloy includes, for example, Co-Fe-Si-B or Co-Fe-Ni-Si-B. The amorphous alloy ribbon may be heat treated at 400-600 DEG C in a nitrogen atmosphere so as to have nanocrystalline microstructure and may be subjected to heat treatment at a temperature below the crystallization temperature, for example, 100-400 DEG C, It is also possible to increase the brittleness of the alloy ribbon.

The total thickness of the soft magnetic metal sheet 100 is appropriately adjusted according to the type of the device to which the soft magnetic metal sheet 100 is applied and the thickness of each soft magnetic metal ribbon 11, 12, 13, 14, 15, 16 according to recent trends of thinning and weight- Is preferably 1 mu m to 30 mu m. The thinner the ribbon, the more likely it is to break the ribbon even after a slight impact during handling after heat treatment. The amorphous soft magnetic ribbon exhibits optimal soft magnetic properties in the range of 15 μm to 30 μm. When the amorphous forming ability is excellent, the soft magnetic characteristics are improved as the thickness is increased, and rapidly decreased as the thickness exceeds 50 μm . The nanocrystalline ribbon shows optimal soft magnetic properties in the range of 10 to 30 μm.

In one preferred example, the soft magnetic ribbon 10 is made of an Fe-based or Co-based amorphous alloy having a thickness of 15 μm to 30 μm, an Fe-based or Co-based nanocrystalline alloy having a thickness of 10 μm to 25 μm, And an alloy containing at least one ferromagnetic element selected from the group consisting of Fe, Ni, and Co.

In FIG. 1, six soft magnetic ribbons 10 are laminated 11, 12, 13, 14, 15 and 16, but the number of laminations is not particularly limited and the kind of soft magnetic metal, Can be properly adjusted. For example, since the Fe-based amorphous alloy has a higher saturation magnetic field than the nano-crystal alloy, it is preferable to use 2 to 8 layers laminated, and it is preferable to use 3 to 5 layers because a high magnetic permeability is obtained. When a soft magnetic ribbon made of a nanocrystalline alloy is used, 4 to 12 layers can be laminated, and 7 to 9 layers can be used because a high magnetic permeability can be obtained.

In another example, when a permanent magnet is employed in a transmitter to calibrate the position of a transmitting antenna and a receiving antenna to an optimum position in a wireless power transmission apparatus, the number of layers of the ribbon sheet It is necessary to determine the number. On the other hand, in the case where the permanent magnet is not employed in the transmitting device of the wireless charger, it is also possible to use a relatively small number of amorphous ribbon sheets as compared with the case of employing permanent magnets.

Specific Permeability (μr) of the soft magnetic metal ribbon 10 may be 10 to 500,000.

The insulating layer 20 inserted between the soft magnetic ribbons 11,12,13,14,15,16 may be made of a thermoplastic resin such as, for example, polyethylene, polypropylene, polyethylene terephthalate, polystyrene or polyvinyl chloride Or a mixture of two or more selected from the group consisting of a polyvinyl alcohol resin, a silicone resin, an epoxy resin, an acrylate resin, a urethane resin, a polyamide resin and a polyimide resin. It is not limited. The thickness of the insulating layer may be 1 nm to 30 탆, preferably 1 탆 to 20 탆. In one preferred example, the insulating layer 20 may be a thermally conductive composite film having a thermal conductivity of 1 W / mK or more. Also, the insulating layer may have a relative permeability ranging from 10 to 200.

FIG. 2 is a view showing distribution of magnetic fluxes M 'in the conventional soft magnetic sheet 1, and FIG. 3 is a graph showing distribution of magnetic fluxes M in the soft magnetic sheet 100 subjected to the magnetic shielding treatment according to an example of the present invention. Fig.

First, in Fig. 2, the conventional ribbon-laminated soft magnetic sheet 1 generates leaked magnetic flux M ' ₁ at the side, thereby reducing power transmission efficiency. Thus, in the present invention, a magnetic circuit is formed by magnetic shielding in order to minimize the leakage magnetic flux M ' ₁ generated on the side surface of the soft magnetic sheet 1.

3, in the soft magnetic sheet 100 in which a plurality of soft magnetic ribbons are laminated, the uppermost layer ribbon 11 and the lowermost layer ribbon 16 are mutually connected in the thickness direction so that the eddy current loss can be effectively And the power transmission efficiency is increased. 3, the laminated uppermost layer 11 is extended to come in contact with the lowermost layer 16, but it is not limited to this as long as it is shielded on the side of the soft magnetic sheet. For example, the lowermost layer may be extended and connected to the uppermost layer, or both the uppermost layer and the lowermost layer may be extended to provide contact in the middle of the side, or the uppermost layer and the lowermost layer may be formed of one connected soft magnetic ribbon.

4 is a photograph showing micro cracks formed in the longitudinal direction of the soft magnetic ribbon in this embodiment. The method of forming the microcracks is not particularly limited. For example, microcracks are formed on the surface when the soft magnetic sheet is heat treated at about 350 ° C to 450 ° C for about 1 hour and then bent more than 25 degrees in the longitudinal direction of the sheet.

The reason why fine cracks are formed on the surface of the soft magnetic ribbon in order to improve the high frequency characteristics by increasing the resistivity of the ribbon. For example, the resistivity of the FeSiB amorphous ribbon increases from 40 mu OMEGA cm to 60 mu OMEGA cm by 400 times at 120 mu OMEGA cm to 140 mu OMEGA cm when a crack is generated. Specifically, when microcracks are formed on the soft magnetic sheet, the reduction of the magnetoresistance R becomes larger than the decrease of the inductance (L) value. As a result, the quality factor Q of the resonant circuit formed by the reception antenna increases, and the power transmission efficiency increases. In addition, the microcrack reduces the loss due to the eddy current, thereby preventing the heat generation of the battery.

FIG. 5 shows a graph showing the skin depth before and after formation of micro cracks. Referring to FIG. 5, it can be seen that the ribbon of 30 .mu.m thickness before the crack is formed can be used up to 1.8 MHz, and after the crack is formed, the used frequency band is extended up to 600 MHz. That is, the ribbons after cracking can be used without difficulty in the NFC band.

Referring to FIG. 6 according to an embodiment of the present invention, when microcracks are formed in the soft magnetic ribbon 10 in the longitudinal direction, the specific resistance increases by 400 times in the direction perpendicular to the crack. However, since the increase of the resistivity in the crack direction is not so large, a process of forming the slit 40 at an interval of 2 mm or more in the direction perpendicular to the direction of the fine crack (the longitudinal direction of the ribbon) in order to increase the resistivity in the crack direction Conduct. When the distance between the slits 40 is less than 2 mm, the volume ratio of the ribbon removed by the slitting process becomes large, so that the overall permeability is lowered and the power transmission efficiency is reduced. The present inventors have experimentally found that the ribbon-laminated sheet having slits formed at intervals of 2 mm in the direction perpendicular to the cracks effectively reduces the eddy current loss and increases the power transmission efficiency by 0.2 to 0.5%.

7 schematically shows a soft magnetic laminated sheet 100 according to an embodiment of the present invention.

7, in the wireless power transmission system, the soft magnetic sheet 100 has a spiral coil 30 formed thereon, and the receiving antenna 30 forms a resonant circuit. Therefore, 100) affects the inductance of the resonant circuit. Since the voltage induced by the upper receiving antenna pattern 30 is determined by the Faraday's law and the Lenz's law, in order to obtain a high voltage signal, the larger the amount of magnetic flux linking with the receiving antenna, the more advantageous . The amount of the magnetic flux increases as the amount of the soft magnetic material contained in the receiving antenna coil 30 increases or as the magnetic permeability of the soft magnetic material increases.

The magnetic field generated by the soft magnetic sheet 100 is generated in the X and Y axes, respectively. When fine cracks are formed in the longitudinal direction of the soft magnetic ribbon, an easy magnetization axis is formed in a longitudinal direction in which cracks are formed. While the magnetic permeability axis decreases perpendicular to the magnetization axis. In the present invention, as shown in FIG. 7, the soft magnetic layers are alternately laminated such that the easy magnetization axes cross each other to effectively block the magnetic field. Specifically, according to the experiment of the present inventors, when a ribbon-laminated sheet laminated by crossing the easy magnetization axes of the ribbon was used, an increase in the power transmission efficiency of 0.5% to 1% was observed when the ribbon laminated sheet was not used.

The present invention provides a soft magnetic sheet for a receiving antenna of a wireless power transmission system that exhibits a high magnetic permeability and minimizes electromagnetic energy leakage while minimizing the influence of eddy current on the surface of the soft magnetic ribbon and preventing magnetization saturation caused by the permanent magnet .

While the present invention has been described in connection with certain exemplary embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

100: Soft magnetic sheet for power receiving antenna
10: Soft magnetic ribbon
20: Insulation layer
30: Power receiving antenna pattern
40: slit

Claims (27)

A plurality of soft magnetic ribbons; And
And a wireless charging coil disposed on the plurality of soft magnetic ribbons,
Wherein the plurality of soft magnetic ribbons comprises a bottom soft magnetic ribbon, a top soft magnetic ribbon, and an interlayer soft magnetic ribbon between the bottom soft magnetic ribbon and the top soft magnetic ribbon,
Wherein the wireless charging coil is disposed on the top layer soft magnetic ribbon,
Wherein each of the plurality of soft magnetic ribbons comprises an Fe-based soft magnetic alloy,
Further comprising an insulating layer disposed between the uppermost soft magnetic ribbon and the middle soft magnetic ribbon and between the bottom soft magnetic ribbon and the middle soft magnetic ribbon,
Wherein at least one of the lowermost soft magnetic ribbon and the top soft magnetic ribbon includes an extension that extends further outward than the outermost side of the middle soft magnetic ribbon,
Wherein the extension is disposed on a side of the middle layer soft magnetic ribbon to reduce leakage flux radiated to a side of the middle soft magnetic ribbon. The method according to claim 1,
The middle layer soft magnetic ribbon
A first interlayer soft magnetic ribbon disposed on the lowermost soft magnetic ribbon and a second interlayer soft magnetic ribbon disposed on the first interlayer soft magnetic ribbon. 3. The method of claim 2,
Wherein the extension extends from the lowermost soft magnetic ribbon and is disposed on a side of the first middle layer soft magnetic ribbon. The method of claim 3,
Wherein an extension of the lowermost soft magnetic ribbon is disposed on a side of the second intermediate soft magnetic ribbon. The method according to claim 1,
Wherein the extension extends from the lowermost soft magnetic ribbon and contacts the top soft magnetic ribbon. 3. The method of claim 2,
Wherein the extension extends from the top layer soft magnetic ribbon and is disposed on a side of the second middle layer soft magnetic ribbon. The method according to claim 6,
Wherein the extension of the top layer soft magnetic ribbon is disposed on a side of the first middle layer soft magnetic ribbon. The method according to claim 1,
Wherein the extension extends from the topmost soft magnetic ribbon and the top soft magnetic ribbon contacts the bottom soft magnetic ribbon. delete The method according to claim 1,
And a crack is formed in at least one of the plurality of soft magnetic ribbons. The method according to claim 1,
The Fe-based soft magnetic alloy includes Fe-Si-B based soft magnetic alloy, Fe-Si-Al based soft magnetic alloy, Fe-Hf-C based soft magnetic alloy, Fe-Cu-Nb- A Fe-Si-N based soft magnetic alloy, a Co-Fe-Si-B based soft magnetic alloy and a Co-Fe-Ni-Si-B based soft magnetic alloy. The method according to claim 1,
Wherein the extension is disposed on at least a portion of the side of the middle layer soft magnetic ribbon. The first soft magnetic ribbon,
A second soft magnetic ribbon disposed on the first soft magnetic ribbon, and
A plurality of soft magnetic ribbons including a third soft magnetic ribbon disposed on the second soft magnetic ribbon;
A wireless charging coil disposed on the third soft magnetic ribbon; And
And an insulating layer disposed between the first soft magnetic ribbon and the second soft magnetic ribbon and between the second soft magnetic ribbon and the third soft magnetic ribbon, respectively
Wherein each of the plurality of soft magnetic ribbons comprises an Fe-based soft magnetic alloy,
Wherein the first soft magnetic ribbon extends further outward than the outermost side of the second soft magnetic ribbon and is disposed on a side of the second soft magnetic ribbon. 14. The method of claim 13,
Wherein the plurality of soft magnetic ribbons further comprise a fourth soft magnetic ribbon disposed between the second soft magnetic ribbon and the third soft magnetic ribbon. 15. The method of claim 14,
Wherein the first soft magnetic ribbon extends further to be disposed on a side of the fourth soft magnetic ribbon. 16. The method of claim 15,
And the first soft magnetic ribbon is in contact with the third soft magnetic ribbon. 15. The method of claim 14,
And an insulating layer disposed between the second soft magnetic ribbon and the fourth soft magnetic ribbon. 14. The method of claim 13,
The Fe-based soft magnetic alloy includes Fe-Si-B based soft magnetic alloy, Fe-Si-Al based soft magnetic alloy, Fe-Hf-C based soft magnetic alloy, Fe-Cu-Nb- A Fe-Si-N based soft magnetic alloy, a Co-Fe-Si-B based soft magnetic alloy and a Co-Fe-Ni-Si-B based soft magnetic alloy. 15. The method of claim 14,
Wherein each of the first soft magnetic ribbon to the fourth soft magnetic ribbon has a thickness of 1 占 퐉 to 30 占 퐉. 15. The method of claim 14,
And each of the first soft magnetic ribbon to the fourth soft magnetic ribbon has a thickness of 15 mu m to 30 mu m. 14. The method of claim 13,
Wherein each of the insulating layers has a thickness of 1 nm to 30 占 퐉. 14. The method of claim 13,
The insulating layer may be formed of a resin such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyvinyl chloride, polyvinyl alcohol resin, silicone resin, epoxy resin, acrylate resin, urethane resin, polyamide resin and polyimide resin The wireless charging device comprising: 14. The method of claim 13,
Wherein the insulating layer has a thermal conductivity of 1 W / mK or more. 15. The method of claim 14,
Wherein a crack is formed on at least one surface of the plurality of soft magnetic ribbons. The first soft magnetic ribbon,
A second soft magnetic ribbon disposed on the first soft magnetic ribbon, and
A plurality of soft magnetic ribbons including a third soft magnetic ribbon disposed on the second soft magnetic ribbon;
A wireless charging coil disposed on the third soft magnetic ribbon; And
And an insulating layer disposed between the first soft magnetic ribbon and the second soft magnetic ribbon and between the second soft magnetic ribbon and the third soft magnetic ribbon,
Wherein each of the plurality of soft magnetic ribbons comprises an Fe-based soft magnetic alloy,
The third soft magnetic ribbon
Wherein the second soft magnetic ribbon extends further outward than the outermost side of the second soft magnetic ribbon and is disposed on a side of the second soft magnetic ribbon. 26. The method of claim 25,
And the third soft magnetic ribbon is disposed on at least a portion of the side of the second soft magnetic ribbon. 26. The method of claim 25,
And the third soft magnetic ribbon is in contact with the first soft magnetic ribbon.

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