KR20160105079A - Wireless power receiving apparatus and wireless power transmitting system comprising the same - Google Patents

Abstract

A wireless power transmitting system according to an embodiment of the present invention includes a wireless power receiving apparatus which includes an electromagnetic wave shielding core, a transmitting coil formed on the electromagnetic wave shielding core, and a hall sensor arranged on the lower part of the electromagnetic wave shielding core, an electromagnetic wave shielding sheet and a receiving coil formed on the electromagnetic wave shielding sheet. The thickness of the electromagnetic wave shielding sheet is 0.4 mm or less. The wireless power receiving apparatus includes soft magnetic alloy with saturation magnetic flux density which is 1.5T or more. So, the wireless power transmitting system can be manufactured at low costs.

Description

TECHNICAL FIELD [0001] The present invention relates to a wireless power receiving apparatus and a wireless power transmission system including the wireless power receiving apparatus.

The present invention relates to wireless charging, and more particularly, to a wireless power receiving apparatus and a wireless power transmission system including the same.

The wireless power transmission apparatus of the wireless power transmission system senses whether the wireless power reception apparatus is disposed on the surface of the wireless power transmission apparatus, and then transmits power to the wireless power reception apparatus. The wireless power transmission device may periodically send a constant signal to the wireless power reception device to sense the wireless power reception device. In this case, there is a disadvantage that the standby power consumption of the wireless power transmission system is large.

A wireless power transmitting apparatus may be equipped with a hall sensor in order to detect the wireless power receiving apparatus. In this case, the disadvantage that the standby power consumption of the wireless power transmission system is large can be solved. However, in order for the hall sensor to detect the wireless power receiving device, the difference in electromotive force between the wireless power receiving device and the wireless power receiving device must be equal to or greater than a predetermined value.

SUMMARY OF THE INVENTION The present invention provides a wireless power receiving apparatus and a wireless power transmission system including the wireless power receiving apparatus.

A wireless power transmission system according to an embodiment of the present invention includes a wireless power transmission device including an electromagnetic wave shielding core, a transmission coil formed on the electromagnetic wave shielding core, and a Hall sensor disposed under the electromagnetic wave shielding core, Sheet and a receiving coil formed on the electromagnetic wave shielding sheet, wherein the electromagnetic wave shielding sheet has a thickness of 0.4 mm or less and a saturation magnetic flux density of 1.5T or more.

The Hall sensor may be disposed at a distance from the center of the transmission coil by a first distance and a second distance below the electromagnetic wave shielding sheet.

The first distance is 1.5 mm, the second distance is 2 mm, and the difference in electromotive force when the wireless power receiving apparatus is disposed on the wireless power transmitting apparatus and when the wireless power receiving apparatus is not disposed may be 40 gauss or more .

The electromagnetic wave shielding sheet may include a soft magnetic alloy containing Fe and Ni or a soft magnetic alloy containing Fe, Cu, B and Si.

The electromagnetic wave shielding sheet may include a soft magnetic alloy containing at least 89 atom% of Fe and Ni.

The electromagnetic wave shielding sheet may include a soft magnetic alloy having a composition represented by the following chemical formula.

Fe _100-a Ni _a

Here, a is 40 to 60 at%.

The electromagnetic wave shielding sheet may include a soft magnetic alloy having a composition represented by the following chemical formula.

Fe _100-xyz Cu _x B _y Si _z

Where x is 0.1 to 2 at%, y is 1 to 3 at%, and z is 6 to 8 at%.

A wireless power receiving apparatus of a wireless power transmission system according to an embodiment of the present invention includes an electromagnetic wave shielding sheet and a receiving coil formed on the electromagnetic wave shielding sheet, wherein the thickness of the electromagnetic wave shielding sheet is 0.4 mm or less, And a soft magnetic alloy having a density of 1.5 T or more.

According to an embodiment of the present invention, it is possible to easily detect whether a wireless power receiving apparatus is disposed on a wireless power transmitting apparatus in a wireless power transmission system. Particularly, a wireless power receiving apparatus that is excellent in detection performance, slim, and low in manufacturing cost can be obtained.

1 is a magnetic induction equivalent circuit.
FIG. 2 is a block diagram illustrating a transmitter as one of the sub-systems constituting the wireless power transmission system.
FIG. 3 is a block diagram illustrating a receiver as one of subsystems constituting a wireless power transmission system.
4 is a partial cross-sectional view of a wireless power transmission system 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.

Hereinafter, a detailed description will be given with reference to the drawings of a wireless power transmission system according to an embodiment of the present invention. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of an apparatus may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

Embodiments use a variety of frequency bands from low frequency (50 kHz) to high frequency (15 MHz) selectively for wireless power transmission, and it is necessary to support a communication system capable of exchanging data and control signals for system control .

The embodiments can be applied to various industrial fields such as a mobile terminal industry using a battery or an electronic device required, a smart clock industry, a computer and notebook industry, a household appliance industry, an electric car industry, a medical device industry, and a robot industry .

Embodiments may consider a system capable of power transmission to one or more multiple devices using one or more transmit coils that provide the device.

According to the embodiment, it is possible to solve the battery shortage problem in a mobile device such as a smart phone and a notebook. For example, when a wireless charging pad is placed on a table and a smart phone or a notebook is used on the table, the battery is automatically charged and can be used for a long time . In addition, by installing wireless charging pads in public places such as cafes, airports, taxis, offices, restaurants, etc., mobile devices manufacturers can charge various mobile devices regardless of charging terminals. In addition, when wireless power transmission technology is applied to household electrical appliances such as cleaners, electric fans, etc., there is no need to look for power cables and complex wires can be eliminated in the home, which can reduce wiring in buildings and increase the space utilization. In addition, it takes a lot of time to charge the electric car with the current household power, but if the high power is transmitted through the wireless power transmission technology, the charging time can be reduced. If the wireless charging facility is installed at the bottom of the parking lot, It is possible to solve the inconvenience of having to prepare.

The terms and abbreviations used in the examples are as follows.

Wireless Power Transfer System: A system that provides wireless power transmission within a magnetic field region

Wireless Power Transfer System-Charger: A device that provides wireless power transmission to power receivers of multiple devices within a magnetic field area and manages the entire system.

Wireless Power Transfer System-Deivce: A device that is provided with a wireless power transmission from a power transmitter within a magnetic field area.

Charging Area: A region where actual wireless power transmission occurs within the magnetic field region, and may vary depending on the size, required power, and operating frequency of the application product.

Scattering parameter: The S parameter is the ratio of the input port to the output port in terms of the input voltage to the output voltage on the frequency distribution (Transmission S21) or the self reflection value of each input / output port, Reflection (S11, S22) of the reflected output.

Quality factor Q: The value of Q in resonance means the quality of frequency selection. The higher the Q value, the better the resonance characteristics. The Q value is expressed as the ratio of the energy stored in the resonator to the energy lost.

One of the principles of wireless power transmission is magnetic induction.

The magnetic induction method is a noncontact energy transfer technique in which an electromotive force is generated in the load inductor Ll via a magnetic flux generated when the source inductor Ls and the load inductor L1 are brought close to each other and a current is supplied to one of the source inductors Ls .

1 is a magnetic induction equivalent circuit.

Referring to FIG. 1, in a magnetic induction equivalent circuit, a transmitter includes a source voltage Vs, a source resistance Rs, a source capacitor Cs for impedance matching, and a magnetic coupling with a receiving unit, And a load coil Rl for an impedance matching and a load coil Ll for magnetic coupling with a transmitting unit. The load coil Rl may be implemented as a source coil Ls for impedance matching, And the degree of magnetic coupling between the source coil Ls and the load coil Ll can be expressed by mutual inductance Msl.

In FIG. 1, the ratio S21 of the input voltage to the output voltage is obtained from the magnetic induction equivalent circuit consisting only of the coil only without the source capacitor Cs for impedance matching and the load capacitor Cl, The power transmission condition satisfies Equation (1) below.

Equation 1

Ls / Rs = L1 / R1

The maximum power transmission is possible when the ratio of the inductance of the transmission coil Ls to the source resistance Rs and the ratio of the inductance of the load coil Ll to the load resistance Rl are equal to each other. Since there is no capacitor capable of compensating for reactance in a system having only inductance, the self reflection value S11 of the input / output port can not be zero at the point where the maximum power transfer is made, and the mutual inductance Msl, The power transfer efficiency can vary greatly depending on the value. Thus, the source capacitor Cs may be added to the transmitter as a compensation capacitor for impedance matching, and the load capacitor Cl may be added to the receiver. The compensation capacitors Cs and Cl may be connected in series or in parallel to the receiving coil Ls and the load coil Ll, respectively. For impedance matching, a passive element such as an additional capacitor and an inductor may be added to each of the transmitter and the receiver as well as the compensation capacitor.

Based on such a wireless power transmission principle, a wireless power transmission system for transmitting power by a magnetic induction method or a self resonance method will be described.

FIG. 2 is a block diagram illustrating a transmitter as one of the sub-systems constituting the wireless power transmission system.

2, the wireless power transmission system may include a transmitting unit 1000 and a receiving unit 2000 for receiving power wirelessly from the transmitting unit 1000. The transmitting unit 1000 may include a transmitting side AC / A transmission side DC / AC conversion unit 1200, a transmission side impedance matching unit 1300, a transmission coil unit 1400, and a transmission side communication and control unit 1500. In this specification, the transmission unit 1000 can be mixed with a wireless power transmission apparatus.

The transmitting side AC / DC converting unit 1100 is a power converting unit for converting an AC signal provided from the outside under the control of the transmitting side communication and control unit 1500 to a DC signal. The transmitting side AC / DC converting unit 1100 includes: May include a rectifier 1110 and a transmission side DC / DC converter 1120 as a subsystem. The rectifier 1110 converts a supplied AC signal into a DC signal. The rectifier 1110 may be a diode rectifier having a relatively high efficiency in high-frequency operation, a synchronous rectifier capable of one-chip operation, And a hybrid rectifier capable of saving space and having a high degree of freedom in dead time. The transmitting side DC / DC converting unit 1120 adjusts the level of the DC signal provided from the rectifier 1110 under the control of the transmitting side communication and control unit 1500. As an example of implementing the DC signal, A buck converter, a boost converter that boosts the level of the input signal, a buck-boost converter or a Cuk converter that can raise or lower the level of the input signal. Also, the transmission side DC / DC converter 1120 includes a switch element that performs a power conversion control function, an inductor and a capacitor that perform a power conversion medium function or an output voltage smoothing function, a voltage gain control function or an electrical isolation function (insulation function) And may have a function of removing a ripple component or a ripple component (AC component included in the DC signal) included in the input DC signal. The error between the command value of the output signal of the transmitting side DC / DC converting unit 1120 and the actual output value can be adjusted through the feedback method and can be performed by the transmitting side communication and control unit 1500 .

The transmission side DC / AC conversion unit 1200 converts the DC signal output from the transmission side AC / DC conversion unit 1100 into an AC signal under the control of the transmission side communication and control unit 1500 and outputs the converted AC signal frequency A half bridge inverter or a full bridge inverter is an example of implementing this system. The transmission side DC / AC conversion unit 1200 may include an oscillator for generating a frequency of an output signal and a power amplifier for amplifying an output signal.

The transmission-side impedance matching unit 1300 minimizes the reflected waves at points having different impedances to improve the signal flow. Since the two coils of the transmitting unit 1000 and the receiving unit 2000 are spatially separated and the leakage of the magnetic field is large, the impedance difference between the two connecting ends of the transmitting unit 1000 and the receiving unit 2000 is corrected, . The impedance matching unit 1300 may include an inductor, a capacitor, and a resistor. Under the control of the communication and control unit 1500, the inductance of the inductor, the capacitance of the capacitor, The impedance value can be adjusted. The transmission impedance matching unit 1300 may have a series resonance structure or a parallel resonance structure when the magnetic induction type wireless power transmission system transmits electric power and the inductive coupling unit between the transmission unit 1000 and the reception unit 2000 The energy loss can be minimized by increasing the coefficient.

The transmitting coil 1400 may be implemented as a plurality of coils or a plurality of coils. If a plurality of transmitting coils 1400 are provided, they may be spaced apart from each other, The overlapping area can be determined in consideration of the deviation of the magnetic flux density. Also, when the transmission coil 1400 is manufactured, it can be manufactured in consideration of the internal resistance and the radiation resistance. If the resistance component is small, the quality factor can be increased and the transmission efficiency can be increased.

The communication and control unit 1500 may include a transmission side control unit 1510 and a transmission side communication unit 1520 as subsystems. The transmission-side controller 1510 may control the output voltage of the transmission-side AC / DC converter 1100 in consideration of the power demand of the receiver 2000, the current charge amount, and the wireless power scheme. The frequency and switching waveforms for driving the transmission side DC / AC conversion unit 1200 may be generated in consideration of the maximum power transmission efficiency to control power to be transmitted. Also, the overall operation of the receiver 2000 can be controlled by using an algorithm, a program, or an application required for the control read from the storage unit (not shown) of the receiver 2000. Meanwhile, the transmission-side controller 1510 may be referred to as a microprocessor, a microcontroller unit, or a microcomputer. The transmission-side communication unit 1520 can perform communication with the reception-side communication unit 2620, and can use a Bluetooth system as an example of a communication system. The transmission side communication unit 1520 and the reception side communication unit 2620 can transmit and receive the charging status information and the charging control command to each other. The charging status information may include the number of the receiving unit 2000, the remaining battery level, the number of times of charging, the amount of usage, the battery capacity, the battery ratio, and the transmission power amount of the transmission unit 1000. Side communication unit 1520 can transmit a charging function control signal for controlling the charging function of the receiving unit 2000 and the charging function control signal controls the receiving unit 2000 to enable or disable the charging function And may be a control signal for disabling the control signal.

Meanwhile, the transmitting unit 1000 may be configured with hardware different from the transmitting-side communication unit 1520, and the transmitting unit 1000 may be communicated in an out-band format. The transmitting unit 1000 and the transmitting-side communication unit 1520 may be implemented in one piece of hardware, and the transmitting unit 1000 may perform communication in an in-band format. The transmission side communication unit 1520 may be configured to be separate from the transmission side control unit 1510 and the reception side communication unit 2620 may be included in the control unit 2610 of the reception device .

FIG. 3 is a block diagram illustrating a receiver as one of subsystems constituting a wireless power transmission system.

3, the wireless power transmission system may include a transmitting unit 1000 and a receiving unit 2000 for wirelessly transmitting power from the transmitting unit 1000. The receiving unit 2000 includes a receiving coil unit 2100 A receiving side AC / DC converting unit 2300, a receiving side DC / DC converting unit 2400, a load unit 2500, and a receiving side communication and controlling unit 2600 have. In this specification, the receiving unit 2000 can be mixed with a wireless power receiving apparatus.

The receiving side coil part 2100 can receive electric power through a magnetic induction method, and one or a plurality of induction coils can be provided. The receiving side coil part 2100 may be provided with a near field communication antenna. The receiving side coil part 2100 may be the same as the transmitting side coil part 1400 and the dimensions of the receiving antenna may be changed according to the electrical characteristics of the receiving part 200. [

The receiving side matching unit 2200 performs impedance matching between the transmitter 1000 and the receiver 2000. [

The receiving-side AC / DC converter 2300 rectifies the AC signal output from the receiving-side coil part 2100 to generate a DC signal.

The receiving-side DC / DC converting section 2400 can adjust the level of the DC signal output from the receiving-side AC / DC converting section 2300 to match the capacity of the load section 2500.

The load unit 2500 may include a battery, a display, a sound output circuit, a main processor, and various sensors.

The receiving side communication and control unit 2600 can be activated by the wake-up power from the transmitting side communication and control unit 1500 and performs communication with the transmitting side communication and control unit 1500, The operation of the system can be controlled.

The receiving unit 2000 includes a single or a plurality of receiving units 2000, and can simultaneously receive energy from the transmitting unit 1000 wirelessly. That is, a plurality of target reception coil sections are independent from each other in the magnetic induction method, and a plurality of target reception sections 2000 can receive power from one transmission section 1000. At this time, the transmitter matching unit 1300 of the transmitter 1000 may adaptively perform impedance matching between the plurality of receivers 2000.

Further, if the receiving unit 2000 is composed of a plurality of units, the same type of system or different types of systems may be used.

Meanwhile, in the case of the radio power transmission of the magnetic induction type, the transmission side AC / DC conversion unit 1100 in the transmission unit 1000 converts the AC signal of 60 Hz to 110 V to 220 V And the transmission side DC / AC conversion unit 1200 can receive the DC signal and output the AC signal of 125 KHz. The receiving side AC / DC converting unit 2300 of the receiving unit 2000 receives the 125 KHz AC signal and converts it into a DC signal of 10 V to 20 V, and the receiving side DC / DC converting unit 2400 converts the DC For example, a 5V DC signal to the load unit 2500 and output it to the load unit 2500.

Meanwhile, the transmitter of the wireless power transmission system senses whether the receiver is disposed on the surface of the transmitter, and then transmits power to the receiver. The transmitter may periodically send a signal to the receiver to detect the receiver. In this case, there is a disadvantage that the standby power consumption of the wireless power transmission system is large.

In order for the transmitter to detect the receiver, a hall sensor may be mounted on the transmitter. In this case, the disadvantage that the standby power consumption of the wireless power transmission system is large can be solved. However, in order for the Hall sensor to detect the receiving part, the difference in electromotive force between the case where the receiving part is disposed on the transmitting part and the case where the receiving part is not disposed should be 40 G (gauss) or more. That is, the voltage difference between the case where the receiving section is disposed on the transmitting section and the case where the receiving section is not disposed on the transmitting section must be 200 mV or more.

On the other hand, an electromagnetic wave shielding sheet having a thickness of 0.4 mm or less is included in the wireless power receiving apparatus in accordance with the tendency of a wireless power receiving apparatus, for example, a mobile apparatus, to become slim. As a result, the performance of the wireless power transmission system to detect the wireless power reception apparatus becomes low. A permanent magnet or the like can be disposed at the center of the coil of the wireless power receiving apparatus. However, the thickness of the wireless power receiving apparatus is increased due to the permanent magnet, and the manufacturing cost is increased.

According to the embodiment of the present invention, the performance of the wireless power transmission system to detect the wireless power receiving apparatus using the electromagnetic wave shielding sheet included in the wireless power receiving apparatus is improved.

4 is a partial cross-sectional view of a wireless power transmission system according to an embodiment of the present invention. In this specification, the transmitter 100 may be mixed with a wireless power transmission device, and the receiver 200 may be mixed with a wireless power receiving device.

4, the transmitter 100 includes an electromagnetic wave shielding core 110, a transmission coil 120 disposed on the electromagnetic wave shielding core 110, and a Hall sensor (Hall) disposed under the electromagnetic wave shielding core 110. [ sensor 130).

Here, the electromagnetic wave shielding core 110 may include a magnetic material, for example, ferrite, and may have a thickness of several mm, for example, about 1 mm. A permanent magnet 140 is further disposed on the electromagnetic wave shielding core 110 and the permanent magnet 140 may be surrounded by the transmission coil 120.

The Hall sensor 130 may be disposed at a distance from the center of the transmission coil 120 by a first distance and a distance from the center of the transmission coil 120 by a second distance to the bottom of the electromagnetic wave shielding core 110. For example, the Hall sensor 130 may be disposed at a distance of 1.5 mm from the center of the transmission coil 120 and 2 mm away from the bottom of the electromagnetic wave shielding core 110.

The Hall sensor 130 senses a change in the magnetic field. That is, the hall sensor 130 senses the receiving unit 200 using the difference in electromotive force between the case where the receiving unit 200 is disposed on the surface 150 of the transmitting unit 100 and the case where the receiving unit 200 is not disposed, A digital ping phase may be initiated. For example, the hall sensor 130 may be disposed on the surface of the transmission unit 100 when the difference in electromotive force between the case where the receiving unit 200 is disposed on the surface 140 of the transmitting unit 100 and the case where the receiving unit 200 is not disposed is 40 G, It can be determined that the receiving unit 200 is disposed on the receiving unit 150.

The receiving unit 200 includes an electromagnetic wave shielding sheet 210, a receiving coil 220 disposed on the electromagnetic wave shielding sheet 210 and an adhesive layer 230 disposed between the electromagnetic wave shielding sheet 210 and the receiving coil 220. [ ).

Here, the thickness of the electromagnetic wave shielding sheet 210 may be 0.4 mm or less, preferably 0.01 mm to 0.4 mm. If the thickness of the electromagnetic wave shielding sheet 210 exceeds 0.4 mm, the wireless power receiving apparatus becomes thick.

The receiving coil 220 may be a coil surface wound on the electromagnetic wave shielding sheet 210 in a direction parallel to the electromagnetic wave shielding sheet 210.

The thickness of the adhesive layer 230 may be 0.05 mm or less.

According to one embodiment of the present invention, the electromagnetic wave shielding sheet 210 includes a soft magnetic alloy having a saturation magnetic flux density Bs of 1.5 T or more. The electromagnetic wave shielding sheet 210 receives a magnetic field from the permanent magnet 140 of the transmitting unit 100 when the receiving unit 200 to which the electromagnetic wave shielding sheet 210 is applied approaches the surface 150 of the transmitting unit 100. When the thickness of the electromagnetic wave shielding sheet 210 is 0.4 mm or less in the case where the soft magnetic alloy having a saturation magnetic flux density Bs of 1.5 T or more is included in the case where the receiving section 200 is disposed on the transmitting section 100 The difference in electromotive force sensed by the Hall sensor 130 in the case where the Hall sensor 130 is turned on may be 40 G, that is, 200 mV or more. As a result, a wireless power transmission system having a slim yet high detection performance can be obtained.

According to one embodiment of the present invention, the electromagnetic wave shielding sheet 210 comprises a soft magnetic alloy containing Fe and Ni or a soft magnetic alloy containing Fe, Cu, B and Si, and at least one of Fe and Ni Or more and 89 at% or more. For example, the electromagnetic wave shielding sheet 210 may comprise a soft magnetic alloy having the composition of Formula (1).

[Chemical Formula 1]

Fe _{100 - a} Ni _a

Here, a is 40 to 60 at%.

The electromagnetic wave shielding sheet 210 may comprise a soft magnetic alloy having the composition of Formula (2).

(2)

Fe _{100 -xy- z} Cu _x B _y Si _z

Where x is 0.1 to 2 at%, y is 1 to 3 at%, and z is 6 to 8 at%.

Thereby, a soft magnetic alloy having a saturation magnetic flux density of 1.5 T or more can be obtained.

The soft magnetic alloy according to one embodiment of the present invention may be prepared by mixing metal powder according to the composition of Chemical Formula 1 or Chemical Formula 2 and then melting at a temperature of 1500 ° C to 1900 ° C and applying a water quenching technique or a melt spinner spinner method, and a spherical powder can be produced by using a gas atomizer or the like. Thereafter, the spherical powder is annealed through a heat treatment process at 300 to 500 ° C, and can be formed into a plate flake.

According to one embodiment of the present invention, a soft magnetic alloy processed into a flake shape can be applied to an electromagnetic wave shielding sheet. The electromagnetic wave shielding sheet according to an embodiment of the present invention may include a soft magnetic alloy and a binder. The electromagnetic wave shielding sheet according to an embodiment of the present invention may comprise 60 to 95 wt%, preferably 88 to 92 wt% of a soft magnetic alloy and 5 to 40 wt%, preferably 8 to 12 wt% of a binder. When the soft magnetic alloy and the binder according to an embodiment of the present invention are mixed according to the content ratio and then pressurized at a high temperature, the electromagnetic wave shielding sheet according to an embodiment of the present invention can be manufactured. Here, the binder may be a thermoplastic resin, a thermosetting resin, an ultraviolet ray curable resin, a radiation curable resin, or the like. For example, the binder may be selected from the group consisting of an epoxy resin, a silicone resin, a silicone rubber, a phenol resin, a urea resin, a melamine resin and a polyvinyl alcohol (PVA) resin. If the electromagnetic wave shielding sheet contains less than 60 wt% of the soft magnetic alloy according to an embodiment of the present invention, the saturation magnetic flux density may be lowered. If the electromagnetic wave shielding sheet contains more than 95 wt%, the bonding force between flakes may be lowered.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

Table 1 shows the composition (at%), the saturation magnetic flux density (T, Tesla), the thickness (mm) of the electromagnetic wave shielding sheet and the electromotive force difference (mV) sensed by the Hall sensor according to Examples and Comparative Examples .

The soft magnetic alloy according to Examples and Comparative Examples were prepared by dissolving the metal powder according to each composition at 1700 캜, cooling it to room temperature by using a water quenching technique, and using a gas atomizer To produce spherical powder. Then, the spherical powder was heat-treated at 350 ° C and processed into flakes.

The saturation magnetic flux density (T) of the soft magnetic alloy flakes produced according to Examples and Comparative Examples was measured using a VSM (Vibrating Sample Magnetometer) instrument. Then, 90 wt% of soft magnetic alloy flake prepared according to Examples and Comparative Examples was mixed with 10 wt% of binder, and then pressurized at a high temperature to produce an electromagnetic wave shielding sheet having a thickness of 0.4 mm. The receiver including the electromagnetic wave shielding sheet fabricated according to the embodiment and the comparative example was placed on a transmitter section including a Hall sensor disposed at a position 1.5 mm away from the center of the transmission coil and spaced apart by 2 mm from the bottom of the electromagnetic wave shield core The difference in electromotive force between before and after placement was measured.

Experiment number Composition (at.%) Saturation magnetic flux density (T) Thickness (mm) Electromotive force difference (mV) Comparative Example 1 Fe _{honey .} Si ₉ Al ₆ 1.0 0.4 155 Comparative Example 2 Fe _{honey .} Si ₁₁ Cr ₂ 1.4 0.4 190 Example 1 Fe _{honey .} Ni ₅₀ 1.5 0.4 205 Example 2 Fe _{honey .} Cu ₁ B ₂ Si ₇ 1.9 0.4 260

Referring to Table 1, when the saturation magnetic flux density is 1.5 T or more, it can be seen that the difference in electromotive force before and after the placement of the receiving portion on the transmitting portion is 200 mV or more, as in Embodiments 1 and 2. It can be seen that the soft magnetic alloy having the same compositions as in Examples 1 and 2 has a higher saturated magnetic flux density than the Fe-Si-Cr series soft magnetic alloy or the Fe-Si-Al series soft magnetic alloy.

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

1100 Transmitter AC / DC converter section
1110 Rectifier
1120 Transmission side DC / DC converter unit
1200 transmission side DC / AC conversion unit
1300 transmitting side impedance matching unit
1400 transmit coil part
1500 Transmitting side communication and control unit
1510 Transmission side control section
1520 transmission side communication unit
2000 receiver
2100 Receiver side coil part
2200 receiving impedance matching unit
2300 receiving AC / DC converter
2400 receiving side DC / DC converting section
2500 Load section
2600 Receive side communication and control unit
2610 Receiving-
2620 Receiving side communication unit
100 transmitter
200 Receiver

Claims (12)

An electromagnetic wave shielding core, a transmission coil formed on the electromagnetic wave shielding core, and a Hall sensor disposed under the electromagnetic wave shielding core, and
And a receiving coil formed on the electromagnetic wave shielding sheet, wherein the thickness of the electromagnetic wave shielding sheet is 0.4 mm or less, and the saturation magnetic flux density is 1.5T or more.
And a wireless power transmission system. The method according to claim 1,
Wherein the Hall sensor is disposed at a distance from the center of the transmission coil by a first distance and a second distance below the electromagnetic wave shielding sheet. 3. The method of claim 2,
The first distance is 1.5 mm, the second distance is 2 mm,
Wherein the difference in electromotive force between the case where the wireless power receiving apparatus is disposed on the wireless power transmitting apparatus and the case where the wireless power receiving apparatus is not disposed is 40 gauss or more. The method according to claim 1,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy comprising Fe and Ni or a soft magnetic alloy comprising Fe, Cu, B and Si. 5. The method of claim 4,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy including at least 89at% of at least one of Fe and Ni. 6. The method of claim 5,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy having a composition of the following formula:
Fe _100-a Ni _a
Here, a is 40 to 60 at%. 6. The method of claim 5,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy having a composition of the following formula:
Fe _100-xyz Cu _x B _y Si _z
Where x is 0.1 to 2 at%, y is 1 to 3 at%, and z is 6 to 8 at%. A wireless power receiving apparatus of a wireless power transmission system,
Electromagnetic wave shielding sheet, and
And a receiving coil formed on the electromagnetic wave shielding sheet,
Wherein the electromagnetic wave shielding sheet has a thickness of 0.4 mm or less and a saturation magnetic flux density of 1.5T or more. 9. The method of claim 8,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy containing Fe and Ni or a soft magnetic alloy containing Fe, Cu, B and Si. 10. The method of claim 9,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy having a composition of the following formula:
Fe _100-a Ni _a
Here, a is 40 to 60 at%. 10. The method of claim 9,
Wherein the electromagnetic wave shielding sheet comprises a soft magnetic alloy having a composition of the following formula:
Fe _100-xyz Cu _x B _y Si _z
Where x is 0.1 to 2 at%, y is 1 to 3 at%, and z is 6 to 8 at%. 9. The method of claim 8,
And an adhesive layer disposed between the electromagnetic wave shielding sheet and the receiving coil.

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