KR101394508B1 - Soft magnetism sheet, wireless power receiving apparatus and wireless charging method of the same - Google Patents

Abstract

A wireless power receiving apparatus capable of performing a wireless power charging operation according to one embodiment of the present invention includes a substrate, a first soft magnetic layer which is laminated on the substrate and is made of soft magnetic materials, a second soft magnetic layer which is laminated on the first soft magnetic layer, is made of the soft magnetic materials, and includes a hole, a receiving antenna which is laminated on the second soft magnetic layer and receives electromagnetic energy from the wireless power receiving apparatus, a circuit unit which is connected to the receiving antenna and converts electromagnetic energy into electric energy, and a battery charged with the electric energy.

Description

TECHNICAL FIELD [0001] The present invention relates to a soft magnetic sheet, a wireless power receiving device, and a wireless charging method therefor. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft magnetic sheet, a wireless power receiving apparatus and a wireless charging method thereof, and more particularly to a structure of a soft magnetic sheet for an antenna included in a wireless power receiving apparatus.

Background Art [0002] With the development of wireless communication technology, there is a growing interest in wireless power transmission / reception technology for wirelessly supplying electric power to electronic devices. Such wireless power transmission / reception technology can be applied not only to battery charging of a portable terminal, but also to power supply for household electric appliances, power supply to electric vehicles and subways.

Typical wireless power transmission and reception techniques utilize the principles of magnetic induction or self-resonance. For example, when electrical energy is applied to a transmission antenna of a wireless power transmission device, the transmission antenna can convert electrical energy into electromagnetic energy and radiate it to the surroundings. The receiving antenna of the wireless power receiving apparatus can receive the electromagnetic energy radiated from the transmitting antenna and convert it into electric energy.

At this time, in order to increase the power transmission / reception efficiency, it is necessary to minimize the energy loss between the wireless power transmission apparatus and the wireless power reception apparatus. To this end, it is necessary to align the transmitting and receiving antennas within the effective distance. In addition, it is necessary to dispose the soft magnetic material around the transmitting antenna and the receiving antenna so that the electromagnetic energy radiated from the transmitting antenna is focused in the direction of the receiving antenna.

Such a soft magnetic material for the receiving antenna may vary depending on the frequency range and the principle (for example, magnetic induction, self resonance).

Generally, the soft magnetic material for the receiving antenna includes at least one of a soft magnetic material (e.g., at least one of Fe-Si-Al, Fe-Si-Cr, and Fe-Si-B, Composite) or a ferrite material is used.

On the other hand, in order to align the transmitting antenna with the receiving antenna, the wireless power transmitting device may include a permanent magnet. When a wireless power receiving device (e.g., a smart phone) is placed on a wireless power transmitting device (e.g., a transmitting pad) for wireless charging, the wireless power receiving device is moved by the force of the permanent magnet included in the wireless power transmitting device So that the transmission antenna and the reception antenna can be calibrated to the optimum position.

However, such a permanent magnet does not greatly affect the soft magnetic material for the transmission antenna having a relatively large thickness, but it can lower the magnetic permeability of the soft magnetic material for the reception antenna. This is because the soft magnetic material having a small thickness has a high magnetic permeability in the planar direction, so that the magnetization value of the soft magnetic material for the receiving antenna can be saturated by the magnetic field generated from the permanent magnet. As a result, the electromagnetic energy from the transmitting antenna leaks, and the transmission efficiency between the transmitting antenna and the receiving antenna is lowered.

Accordingly, a technique of obtaining a soft magnetic material having a high saturation magnetization by using a metal material has been proposed. However, even when such a soft magnetic material is used, a low power receiving efficiency is obtained as compared with the case of using a wireless power transmitting apparatus not including a permanent magnet.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure of a soft magnetic sheet for a receiving antenna for improving wireless power receiving efficiency of a wireless power receiving apparatus.

Another object of the present invention is to provide a structure of a soft magnetic sheet capable of simultaneously mounting a wireless power transmission / reception function and a local communication function.

A wireless power receiving apparatus for wirelessly charging power according to an embodiment of the present invention includes a substrate, a first soft magnetic layer stacked on the substrate and made of a soft magnetic material, a second soft magnetic layer stacked on the first soft magnetic layer, A second soft magnetic layer formed of a soft magnetic material and including a hole, a reception antenna stacked on the second soft magnetic layer and configured to receive electromagnetic energy emitted from a wireless power transmission device, A circuit for converting the electromagnetic energy to electrical energy, and a battery for charging the electrical energy.

The magnetic permeability of the first soft magnetic layer may be higher than that of the second soft magnetic layer.

The first soft magnetic layer and the second soft magnetic layer may be attached with an adhesive sheet of an insulating material.

The second soft magnetic layer may further include a near field communication (NFC) antenna formed of a ferrite material and stacked on the second soft magnetic layer and surrounding the receive antenna.

The first soft magnetic layer may be formed of a heat-treated amorphous ribbon.

At least one crack may be formed in the first soft magnetic layer.

The reception antenna may comprise a coil surface wound on the second soft magnetic layer in a direction parallel to the second soft magnetic layer, and the hole may be formed inside the coil surface.

The first soft magnetic layer may cover at least a part of the coil surface.

The hole may be formed at a position opposite to the permanent magnet included in the wireless power transmission device, and the diameter of the hole may be 0.5 to 1.5 times the diameter of the permanent magnet.

A wireless charging method of a wireless power receiving apparatus according to an embodiment of the present invention includes the steps of passing a magnetic field generated from a permanent magnet of a wireless power transmission apparatus through a hole formed in a first soft magnetic layer of the wireless power receiving apparatus, Collecting electromagnetic energy radiated from a transmitting antenna of the wireless power transmission apparatus, converting the collected electromagnetic energy into electrical energy, converting the electromagnetic energy into electrical energy, And charging using the converted electrical energy.

A soft magnetic sheet of a wireless power receiving apparatus according to an embodiment of the present invention includes a first soft magnetic layer made of a soft magnetic material, a second soft magnetic layer stacked on the first soft magnetic layer and made of a soft magnetic material, A second soft magnetic layer, and a receiving antenna stacked on the second soft magnetic layer and receiving electromagnetic energy emitted from the wireless power transmission device.

According to the embodiment of the present invention, the electromagnetic energy focusing performance of the receiving antenna can be enhanced in the wireless power receiving apparatus, and the wireless power transmitting / receiving efficiency can be maximized. In addition, it is possible to obtain a desired electromagnetic energy focusing effect even in a thin thickness, and thus it can be applied to a variety of electronic devices (eg, TV, portable terminal, notebook, and tablet PC) having a slim trend.

Further, since the electromagnetic energy focusing performance is excellent and the material cost is low, it can be applied to large-sized applications such as electric vehicles, subways, and electric trains.

Further, even if the wireless power transmission apparatus includes a permanent magnet, the influence of the permanent magnet can be absorbed, and high power transmission efficiency can be obtained. It is also compatible with the case where the wireless power transmission device does not include a permanent magnet.

Further, the process for manufacturing the soft magnetic sheet is simple, and the burden of the additional cost increase is small.

In particular, a soft magnetic sheet can be obtained that simultaneously ensures NFC performance and WPC performance.

1 is a block diagram illustrating a wireless power transceiver system in accordance with an embodiment of the present invention.
FIG. 2 is a diagram showing a part of a wireless power transmission apparatus, and FIG. 3 is a diagram showing a part of a wireless power reception apparatus.
FIG. 4 is a cross-sectional view of a soft magnetic layer included in a wireless power receiving apparatus, and FIG. 5 is a diagram showing a magnetic saturation phenomenon of the soft magnetic layer of FIG.
FIG. 6 is another example of a cross-sectional view of a soft magnetic layer included in a wireless power receiving apparatus, FIG. 7 is a top view of the soft magnetic layer of FIG. 6, and FIG. 8 is a diagram showing a magnetic saturation phenomenon of the soft magnetic layer of FIG.
FIG. 9 is a cross-sectional view of a soft magnetic layer included in a wireless power receiving apparatus according to an embodiment of the present invention, and FIG. 10 is a diagram illustrating a magnetic path formed around the soft magnetic layer in FIG.
11 is a flowchart showing a wireless charging method of a wireless power receiving apparatus according to an embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 is a block diagram illustrating a wireless power transceiver system in accordance with an embodiment of the present invention.

Referring to FIG. 1, a wireless power transmission / reception system includes a wireless power transmission apparatus 100 and a wireless power reception apparatus 200. The wireless power transmission apparatus 100 applies electrical energy to a transmission antenna, and the transmission antenna converts electrical energy into electromagnetic energy and radiates it to the surroundings. The wireless power receiving apparatus 200 receives electromagnetic energy radiated from a transmitting antenna using a receiving antenna and converts the received electromagnetic energy into electric energy to charge the antenna.

Here, the wireless power transmission apparatus 100 is, for example, a transmission pad. The wireless power receiving apparatus 200 may be a portable terminal to which wireless power transmission / reception technology is applied, a household / personal electronic product, a transportation means, and the like. A mobile terminal to which the wireless power transmission / reception technology is applied, a household / personal electronic product, a transportation means, etc. may include only the wireless power receiving apparatus 200 or may include both the wireless power transmitting apparatus 100 and the wireless power receiving apparatus 200 Can be set.

Meanwhile, the wireless power receiving apparatus 200 may be configured to include a module having both a wireless power conversion (WPC) function and a near field communication (NFC) function. At this time, the wireless power receiving apparatus 200 may perform short-range wireless communication with the external apparatus 300 including the NFC module.

FIG. 2 is a diagram showing a part of a wireless power transmission apparatus, and FIG. 3 is a diagram showing a part of a wireless power reception apparatus.

2, the wireless power transmission apparatus 100 includes a transmission circuit (not shown), a soft magnetic core 110, a transmission antenna 120, and a permanent magnet 130.

The soft magnetic core 110 may be made of a soft magnetic material having a thickness of several mm. The transmission antenna 120 may be a transmission coil, and the permanent magnet 130 may be surrounded by a transmission antenna 120.

Referring to FIG. 3, the wireless power transmission apparatus 200 includes a reception circuit (not shown), a soft magnetic layer 210, and a reception antenna 220. The soft magnetic layer 210 may be laminated on a substrate (not shown). The substrate may be composed of multiple layers of fixed sheets and may be bonded to the soft magnetic layer 210 to fix the soft magnetic layer 210.

The soft magnetic layer 210 concentrates the electromagnetic energy radiated from the transmitting antenna 120 of the wireless power transmission apparatus 100.

The soft magnetic layer 210 may be formed of a metal material or a ferrite material and the soft magnetic layer 210 may be formed in various forms such as a sintered body (pellet), a plate, a ribbon, a foil, . ≪ / RTI > As an example, the soft magnetic layer 210 may be in the form of a composite comprising a single metal or alloy powder flake comprising at least one of Fe, Co, Ni and a polymeric resin. As another example, the soft magnetic layer 210 may be an alloy ribbon, laminated ribbon, foil or film comprising at least one of Fe, Co, and Ni. As another example, the soft magnetic layer 210 may be a composite containing 90 wt% or more of FeSiCr flakes and 10 wt% or less of the polymer resin. As another example, the soft magnetic layer 210 may be a sheet, ribbon, foil or film containing Ni-Zn ferrite.

A reception antenna 220 is stacked on the soft magnetic layer 210. The receiving antenna 220 may be a coiled surface wound in a direction parallel to the soft magnetic layer 210 on the soft magnetic layer 210. For example, a receiving antenna applied to a smart phone may be in the form of a spiral coil having an outer diameter of 50 mm or less and an inner diameter of 20 mm or more. The receiving circuit converts the electromagnetic energy received through the receiving antenna 220 into electric energy, and charges the battery (not shown) with the converted electric energy.

Although not shown, a heat dissipation layer may be further included between the soft magnetic layer 210 and the reception antenna 220. In this specification, the soft magnetic layer 210 and the receiving antenna 220 may be referred to as a soft magnetic sheet. The soft magnetic sheet may mean not only a flexible structure but also a rigid structure such as a sintered body, a plate and the like.

When the wireless power receiving apparatus 200 has the WPC function and the NFC function at the same time, the NFC coil 230 may be further stacked on the soft magnetic layer 210. The NFC coil 230 may be formed to surround the outside of the receiving antenna 220.

Each of the reception antenna 220 and the NFC coil 230 may be electrically connected to each other through a terminal 240.

Equation (1) represents the magnetic inductance coupling coefficient.

Where Lx is the self inductance of the receiving antenna, L _Tx is the self inductance of the transmitting antenna, and M is the inductance of the transmitting antenna and the receiving antenna, where k is the inductive coupling coefficient, L _Rx is the self- (mutual inductance).

In the case where the wireless power transmission apparatus includes a permanent magnet and the distance between the transmission antenna and the reception antenna is 5 mm and the thickness of the soft magnetic layer in which the reception antenna is stacked is 0.2 mm, And has a value of 0.75 to 0.8. In other words, it is common to obtain a transmission efficiency of 6-70% considering the loss of conduction and the loss of circuit.

FIG. 4 is a cross-sectional view of a soft magnetic layer included in a wireless power receiving apparatus, and FIG. 5 is a diagram showing a magnetic saturation phenomenon of the soft magnetic layer of FIG. For ease of explanation, FIG. 5 shows only some of the components of the soft magnetic layer of FIG. 4, and FIG. 4 is inverted 180 degrees to illustrate interaction with a wireless power transmission device.

Referring to FIG. 4, a reception antenna 220 and an NFC coil 230 are stacked on the soft magnetic layer 210. The adhesive sheet 400 may be used for bonding the soft magnetic layer 210 and the receiving antenna 220 and the NFC coil 230. [ A polyimide (PI) film 410 may be further laminated on the reception antenna 220 and the NFC coil 230. Here, the thickness of the soft magnetic layer 210 is 0.1 to 0.3 mm, and the thickness of the reception antenna 220 and the NFC coil 230 is 0.05 to 0.15 mm. The thickness of the adhesive sheet 400 is 0.02 mm to 0.06 mm, and the thickness of the PI film 410 is 0.01 mm to 0.05 mm. For example, the thickness of the soft magnetic layer 210 may be 0.2 mm, and the thickness of the reception antenna 220 and the NFC coil 230 may be 0.1 mm. The thickness of the adhesive sheet 400 is 0.04 mm, and the thickness of the PI film 410 may be 0.03 mm. Further, a heat radiation sheet (not shown) having a thickness of 0.07 to 0.1 mm may be further attached under the soft magnetic layer 210.

4 and 5, when the wireless power transmission apparatus 100 includes the permanent magnet 130, the soft magnetic layer 210 is saturated by the magnetic field generated by the permanent magnet 130. Accordingly, the electromagnetic energy transmitted from the transmitting antenna 120 can not be sufficiently focused on the receiving antenna 220, resulting in a low power transmission efficiency.

FIG. 6 is another example of a cross-sectional view of a soft magnetic layer included in a wireless power receiving apparatus, FIG. 7 is a top view of the soft magnetic layer of FIG. 6, and FIG. 8 is a diagram showing a magnetic saturation phenomenon of the soft magnetic layer of FIG. For ease of explanation, FIG. 8 shows only some of the components of the soft magnetic layer of FIG. 6 and is illustrated with FIG. 6 inverted 180 degrees to illustrate the interaction with the wireless power transmission device.

Referring to FIG. 6, a reception antenna 220 and an NFC coil 230 are stacked on the soft magnetic layer 210. The adhesive sheet 400 may be used for bonding the soft magnetic layer 210 and the receiving antenna 220 and the NFC coil 230. [ The PI film 410 may be further laminated on the reception antenna 220 and the NFC coil 230.

6 to 8, the soft magnetic layer 210 includes a hole 600. The hole 600 may be formed at a position opposite to the permanent magnet 130 included in the wireless power transmission apparatus 100 (e.g., inside the coil surface forming the receiving antenna 220). The hole 600 may be formed at a level of 0.5 to 1.5 times the diameter of the permanent magnet 130. For example, when the diameter of the permanent magnet 130 is 12 mm, the diameter of the hole 230 may be 6 mm to 18 mm. Thus, by passing the magnetic field generated by the permanent magnet 130 by the hole 600, the area of the soft magnetic layer 210 exposed to the magnetic field can be reduced. However, the magnetic field passing through the hole 600 can flow again through the soft magnetic layer 210. Accordingly, although the magnetization value of the soft magnetic layer 210 can be lowered compared with the case where the holes 600 are not provided, the magnetization value of the soft magnetic layer 210 is still high, and a satisfactory power transmission efficiency may not be obtained.

On the other hand, ferrite materials are cheaper than metal materials and have high reliability. In addition, the ferrite material exhibits high magnetic permeability and low loss rate in the NFC frequency band, while the metal material exhibits low permeability and high loss ratio in the NFC frequency band.

Accordingly, if the effect of the ferrite-based soft magnetic layer on the permanent magnet can be reduced, it is possible not only to increase the power transmission efficiency, but also to obtain a soft magnetic layer capable of satisfying NFC performance and WPC performance at the same time.

In the embodiment of the present invention, the structure of the soft magnetic layer in which the reception antennas are stacked is changed to enhance the efficiency of wireless power transmission / reception. That is, the magnetization value of the soft magnetic layer is intended to be lowered by changing the path of the magnetic field generated by the permanent magnet of the wireless power transmission device. Further, it is intended to obtain a soft magnetic sheet which satisfies NFC performance and WPC performance at the same time by increasing the power transmission efficiency of the ferromagnetic soft magnetic layer.

FIG. 9 is a cross-sectional view of a soft magnetic layer included in a wireless power receiving apparatus according to an embodiment of the present invention, and FIG. 10 is a diagram illustrating a magnetic path formed around the soft magnetic layer in FIG. For convenience of illustration, FIG. 10 shows only some of the components of the soft magnetic layer of FIG. 9 and is illustrated with FIG. 9 inverted 180 degrees to illustrate interaction with a wireless power transmission device. The description of the elements overlapping with those of FIGS. 1 to 8 with respect to the soft magnetic layer 210, the reception antenna 220, the NFC coil 230, the hole 600, etc. will be omitted.

9, a soft magnetic layer 210 is laminated on a ribbon 900 made of a soft magnetic material, and a receiving antenna 220 and an NFC coil 230 are laminated on the soft magnetic layer 210. The adhesive sheet 400 may be used for bonding the soft magnetic layer 210 and the receiving antenna 220 and the NFC coil 230. [ A polyimide (PI) film 410 may be further laminated on the reception antenna 220 and the NFC coil 230. The soft magnetic layer 210 includes at least one hole 600. The holes 600 may have various shapes such as circular, oval, and polygonal.

The ribbon 900 may be a heat-treated amorphous ribbon, and the permeability of the ribbon 900 is higher than that of the soft magnetic layer 210. The ribbon 900 may be made of a soft magnetic material. For example, the ribbon 900 may be a metal composite material including at least one of Fe, Co, and Ni, or may be made of a ferrite material. The ribbon 900 and the soft magnetic layer 210 may be attached to an adhesive sheet 910 of an insulating material. The ribbon 900 may be formed in the same size as the soft magnetic layer 210, but is not limited thereto. When the ribbon 900 is formed to cover at least a part of the receiving antenna 220, the magnetic field from the permanent magnet 130 can be collected. In this specification, the ribbon 900 may be mixed with the first soft magnetic layer, and the soft magnetic layer 210 may be mixed with the second soft magnetic layer.

9 and 10, when the wireless power transmission apparatus 100 includes the permanent magnet 130, the magnetic field generated by the permanent magnet 130 passes through the hole 600 formed in the soft magnetic layer 210 do. The magnetic field passing through the hole 600 is transmitted to the ribbon 900. The magnetic field flowing along the planar direction of the ribbon 900 again forms a magnetic path to the soft magnetic core 110 of the wireless power transmission device 100.

The magnetic field generated by the permanent magnet 130 hardly affects the magnetization value of the soft magnetic layer 210 and the electromagnetic energy transmitted by the transmission antenna 120 is sufficiently focused on the reception antenna 220 And the power transmission efficiency is increased.

The thickness of the soft magnetic layer 210 is 0.1 to 0.3 mm and the thickness of the reception antenna 220 and the NFC coil 230 is 0.05 to 0.15 mm. The thickness of the adhesive sheet 400 is 0.02 mm to 0.06 mm, and the thickness of the PI film 410 is 0.01 mm to 0.05 mm. The thickness of the ribbon 900 is 0.01 mm to 0.05 mm, and the thickness of the adhesive sheet 910 is 0.01 to 0.03 mm. For example, the thickness of the soft magnetic layer 210 may be 0.2 mm, and the thickness of the reception antenna 220 and the NFC coil 230 may be 0.1 mm. The thickness of the adhesive sheet 400 is 0.04 mm, and the thickness of the PI film 410 may be 0.03 mm. The thickness of the ribbon 900 is 0.03 mm, and the thickness of the adhesive sheet 910 may be 0.01 mm. Thus, even if the ribbon 900 is added, the overall thickness does not increase significantly. Therefore, a wireless power receiving apparatus having a high power transmission efficiency and a small thickness can be realized.

Although not shown, the ribbon 900 may include at least one crack. The crack means a crack or a crack formed in the ribbon 900. The crack can be formed in the process of manufacturing the ribbon 900. For example, it is possible to increase the frequency of cracks formed in the ribbon 900 by adjusting the temperature or the pressure in the course of manufacturing the ribbon 900. The cracks formed on the ribbon 900 can block the eddy current that may flow on the ribbon 900 by the electromotive force. Accordingly, it is possible to reduce the loss due to the eddy current and to increase the quality factor at high frequencies.

Table 1 shows the experimental results of the power transmission efficiency according to the soft magnetic layer of the wireless power receiving apparatus. The permanent magnet used in the experiment was a NdFeB permanent magnet having a diameter of 12 mm and a composite material (permeability: 50) containing 0.2 wt% of FeSiCr flake in a metal material of 90 wt% or more was used as the soft magnetic layer of the ferrite material. A Ni-Zn ferrite sheet (permeability: 120 to 130) having a thickness of 0.2 mm was used. The hole formed in the soft magnetic layer had a diameter of 18 mm and a 0.03 mm thick FeSiB amorphous ribbon (permeability: 800 to 1000) heat treated at 380 ° C for 1 hour was used, and the ribbon and soft magnetic layer were both- Respectively. The transmission power efficiency was measured with the distance between the transmitting antenna and the receiving antenna adjusted to 5 mm.

No. Permanent magnet Soft magnetic layer material hall ribbon Power Transmission Efficiency (%) One Not included Ferrite material × × 66.2 2 include Ferrite material × × 53.8 3 include Ferrite material ○ × 56 4 include Ferrite material ○ ○ 61.5 5 Not included Metal material × × 62.2 6 include Metal material × × 58.2 7 include Metal material ○ × 59 8 include Metal material ○ ○ 61.1

According to Table 1, when the wireless power transmission device does not include a permanent magnet, the power transmission efficiency of the soft magnetic layer of the metal material is 62.2% and the power transmission efficiency of the ferrite soft magnetic layer is 66.2%. However, when the wireless power transmission device includes a permanent magnet, the power transmission efficiency of the soft magnetic layer of the metal material is 57.6%, and the power transmission efficiency of the ferrite soft magnetic layer is reduced to 53.8%. From this, it can be seen that the ferromagnetic material layer of the ferrite material is more affected by the permanent magnet.

On the other hand, when holes are formed in the soft magnetic layer of the ferrite material, the power transmission efficiency is increased to 56%, but the power transmission efficiency is further increased to 61.5% when the ribbon is added. As described above, it can be seen that the addition of the ribbon prevents the magnetic saturation phenomenon of the ferrite-based soft magnetic layer by 60% or more (7.7 (= 61.5-53.8) /12.4 (66.2-53.8) * 100).

In the case of a soft magnetic layer made of a metal material, the power transmission efficiency is increased to 59% when the hole is formed, but it is increased to 61.1% when the ribbon is added. As described above, it can be seen that the addition of the ribbon prevents the magnetic saturation phenomenon of the soft magnetic layer of the metal material by 70% or more (2.9 (61.1-58.2) / 4 (62.2-58.2) * 100).

Thus, by adding a ribbon to the soft magnetic layer in which the holes are formed, the influence of the magnetic field generated from the permanent magnet can be minimized, and the power transmission efficiency can be maximized.

In particular, ferrite materials are cheaper than metal materials and have high reliability. In addition, the ferrite material exhibits high magnetic permeability and low loss rate in the NFC frequency band, while the metal material exhibits low permeability and high loss ratio in the NFC frequency band.

Thus, by reducing the influence of the ferrite-based soft magnetic layer on the permanent magnet, a soft magnetic layer capable of satisfying NFC performance and WPC performance can be obtained at the same time.

Hereinafter, a wireless charging method using a wireless power receiving apparatus including a soft magnetic layer according to an embodiment of the present invention will be described.

11 is a flowchart showing a wireless charging method of a wireless power receiving apparatus according to an embodiment of the present invention.

11, the wireless power receiving apparatus 200 allows a magnetic field, which is generated from the permanent magnet 130 of the wireless power transmission apparatus 100, to pass through a hole formed in the soft magnetic layer 210 (S1100).

Next, the magnetic field passing through the holes is concentrated using the ribbon 900 attached to the soft magnetic layer 210 (S1110). Accordingly, the magnetic field flows along the planar direction of the ribbon 900, and then forms a magnetic path to the soft magnetic core 110 of the wireless power transmission device 100.

The receiving antenna 220 of the wireless power receiving apparatus 200 collects the electromagnetic energy radiated from the transmitting antenna 120 of the wireless power transmitting apparatus 100 (S1120). The receiving circuit of the wireless power receiving apparatus 200 converts the electromagnetic energy collected by the receiving antenna 220 into electrical energy (S1130), and charges the electrical energy using the converted electrical energy (S1140).

As described above, the magnetic field from the permanent magnet is passed through the hole formed in the soft magnetic layer of the wireless power receiver, and then flows along the ribbon, thereby preventing the magnetic field from being transmitted through the plane direction of the soft magnetic layer, Saturation can be prevented. Thus, the power transmission efficiency from the transmitting antenna to the receiving antenna can be increased.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

200: Wireless power receiving device
210: soft magnetic layer
220: receiving antenna
230: NFC coil
600: hole
900: Ribbon

Claims (6)

1. A wireless power receiving apparatus for wirelessly charging power, comprising:
Board,
A first soft magnetic layer formed on the substrate and made of a soft magnetic material,
A second soft magnetic layer laminated on the first soft magnetic layer and made of a soft magnetic material and including a hole,
A receiving antenna that is stacked on the second soft magnetic layer and receives electromagnetic energy radiated from the wireless power transmission device,
A circuit unit connected to the reception antenna and converting the electromagnetic energy into electric energy, and
A battery for charging the electric energy
And the wireless power receiving device. The method according to claim 1,
Wherein the magnetic permeability of the first soft magnetic layer is higher than that of the second soft magnetic layer. The method according to claim 1,
Wherein the first soft magnetic layer and the second soft magnetic layer are attached as an adhesive sheet of an insulating material. The method according to claim 1,
Wherein the second soft magnetic layer is made of a ferrite material,
And a near field communication (NFC) antenna stacked on the second soft magnetic layer and surrounding the receiving antenna. The method according to claim 1,
Wherein the first soft magnetic layer comprises a heat-treated amorphous ribbon. The method according to claim 1,
Wherein at least one crack is formed in the first soft magnetic layer.

Images