KR20210070760A - Magnetic pad, prepration method thereof, and wireless charging device - Google Patents

Abstract

By simply adding a heat dissipation filler with a controlled electrical property and particle size to an organic/inorganic composite magnetic pad, a magnetic pad according to one embodiment is capable of improving a magnetic property and a heat dissipation property of the magnetic pad simultaneously, and being manufactured by a simple process. Accordingly, a wireless charging device comprising the magnetic pad may be usefully used in an electric vehicle and the like requiring a large-capacity power transmission between a transmitter and a receiver. The magnetic pad comprises: a polymer resin; a metal-based magnetic filler; and a heat dissipation filler.

Description

Magnetic pad, manufacturing method thereof, and wireless charging device including same {MAGNETIC PAD, PREPRATION METHOD THEREOF, AND WIRELESS CHARGING DEVICE}

Embodiments relate to a magnetic pad, a method for manufacturing the same, and a wireless charging device including the same. More specifically, the embodiment relates to a magnetic pad having high magnetic properties that can be used in an electric vehicle (EV), a method for manufacturing the same, and a wireless charging device including the same.

Today, the information and communication field is developing at a very fast pace, and various technologies that comprehensively combine electricity, electronics, communication, and semiconductor are continuously being developed. In addition, as the trend toward mobile electronic devices increases, research on wireless communication and wireless power transmission technology is actively conducted in the communication field. In particular, research on a method of wirelessly transmitting power to an electronic device or the like is being actively conducted.

The wireless power transmission wirelessly transmits power through space using an electromagnetic field resonance structure such as magnetic coupling, capacitive coupling, or an antenna without physical contact between a transmitter that supplies power and a receiver that receives power. will be sent to The wireless power transmission is suitable for portable communication devices and electric vehicles that require a large-capacity battery, and since the contacts are not exposed, there is little risk of a short circuit, and a wired charging failure phenomenon can be prevented.

Meanwhile, as interest in electric vehicles has rapidly increased in recent years, interest in building charging infrastructure is increasing. Various charging methods such as electric vehicle charging using home chargers, battery replacement, fast charging devices, and wireless charging devices have already appeared, and new charging business models have also begun to appear (refer to Korean Patent Application Laid-Open No. 2011-0042403). In addition, electric vehicles and charging stations that are being tested in Europe are starting to stand out, and in Japan, car manufacturers and electric power companies are piloting electric vehicles and charging stations.

Korean Patent Publication No. 2011-0042403

A wireless charging device generally includes a magnetic pad for focusing a magnetic field, and as such a magnetic pad, an organic-inorganic composite magnetic pad having flexibility rather than a rigid ferrite sintered sheet is preferred. However, as shown in FIG. 2 , in the conventional organic-inorganic composite magnetic pad 101 , the eddy current increases due to the formation of the conductive network 150 by the contact between the magnetic fillers 110 having conductivity, so that the investment loss compared to the ferrite sintered sheet and increased heat generation.

In addition, a heat dissipation filler may be added to the magnetic pad to reduce heat generation, but it is difficult to prevent the formation of a conductive network between the magnetic fillers because the carbon-based heat dissipation filler generally used has conductivity, or a non-conductive heat dissipation filler is applied to the magnetic pad. Even with the addition, it was not easy to implement effective insulating properties between the magnetic fillers. In addition, insulating coating the surface of the magnetic filler may be considered to prevent eddy currents, but the process cost and time required for the additional insulating coating are required, and the magnetic properties are easily degraded by the insulating coating, and there is a limit to improving the heat dissipation of the magnetic pad there is

As a result of research conducted by the present inventors, it was found that the magnetic and heat dissipation characteristics of the magnetic pad could be simultaneously improved by simply adding a heat dissipation filler with controlled electrical properties and particle size to the organic/inorganic composite magnetic pad.

Accordingly, embodiments are to provide a magnetic pad that can exhibit additional heat dissipation performance while suppressing heat dissipation and deterioration of magnetic properties due to aggregation between magnetic fillers and can be manufactured by a simple process and a wireless charging device including the same.

According to one embodiment, a polymer resin; a metal-based magnetic filler dispersed in the polymer resin; and a heat dissipation filler dispersed in the polymer resin and having insulating properties, satisfying the following formula (1), a magnetic pad is provided:

5 ≤ d1/d2 ≤ 500 (1)

In the above formula, d1 and d2 are the average particle diameters of the magnetic filler and the heat dissipation filler, respectively.

According to another embodiment, a polymer resin; a metal-based magnetic filler dispersed in the polymer resin; and a heat dissipation filler dispersed in the polymer resin and having insulation, wherein the heat dissipation filler surrounds the magnetic filler, a magnetic pad is provided.

According to another embodiment, there is provided a wireless charging device including the magnetic pad according to the embodiment.

The magnetic pad according to the embodiment can improve the magnetic and heat dissipation characteristics of the magnetic pad at the same time by simply adding a heat dissipation filler whose electrical characteristics and particle size are controlled to the organic-inorganic composite magnetic pad, and can be manufactured by a simple process.

In particular, since the particle size ratio between the magnetic filler and the heat-dissipating filler is adjusted to a specific range, the heat-dissipating filler can easily form a structure surrounding the magnetic filler, thereby reducing magnetic properties due to aggregation between the magnetic fillers and heat generation due to the formation of a conductive network. It is possible to further improve heat dissipation while preventing it.

Accordingly, the wireless charging device including the magnetic pad may be usefully used in an electric vehicle requiring large-capacity power transmission between a transmitter and a receiver.

1 is a cross-sectional view of a magnetic pad according to an embodiment.
2 is a cross-sectional view of a conventional organic-inorganic composite magnetic pad.
3 is a diagram illustrating a configuration of a wireless charging device according to an embodiment.
4 illustrates an electric vehicle including a wireless charging device according to an exemplary embodiment.

In the description of the embodiments below, one component is described as being formed above or below another component, one component is directly above or below another component, or indirectly through another component including all that are formed by

In addition, the reference for the upper / lower of each component will be described based on the drawings. The size of each component in the drawings may be exaggerated for explanation, and may be different from the size actually applied.

In the present specification, "including" any component means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in this specification are modified by the term "about" in all cases unless otherwise specified.

In the present specification, unless otherwise specified, the expression "a" or "a" is interpreted as meaning including the singular or the plural as interpreted in context.

[magnetic pad]

1 is a cross-sectional view of a magnetic pad according to an embodiment.

Referring to Figure 1, the magnetic pad 100 is a polymer resin; a metal-based magnetic filler 110 dispersed in the polymer resin; and a heat dissipation filler 120 dispersed in the polymer resin and having insulation.

In addition, in the magnetic pad 100 , the heat dissipation pillar 120 includes a structure surrounding the magnetic pillar 110 . Accordingly, there may be no direct contact between the magnetic pillars 110 by the heat dissipation pillar 120 .

Hereinafter, each component and characteristic of the magnetic pad will be described in detail.

Filler particle size and content

The magnetic pad according to the embodiment satisfies the following formula (1):

5 ≤ d1/d2 ≤ 500 (1)

In the above formula, d1 and d2 are the average particle diameters of the magnetic filler and the heat dissipation filler, respectively.

When the particle size ratio is within the range, it is advantageous to have a structure in which the magnetic filler is surrounded by the heat dissipation filler in the magnetic pad. If the particle size ratio is out of the range, the magnetic filler in the magnetic pad does not have a structure surrounded by the heat dissipation filler, so that the magnetic filler aggregates to form a conductive network through direct contact between them, resulting in an increase in eddy current This can generate a lot of heat.

For example, the d1/d2 ratio may be 5 or more, 10 or more, 20 or more, 50 or more, 100 or more, or 200 or more, and may be 500 or less, 300 or less, 200 or less, or 100 or less. Specifically, the d1/d2 ratio may be 10 to 500, 20 to 500, 5 to 300, or 5 to 200. More specifically, the d1/d2 ratio may be 10 to 100, or 20 to 100.

In this case, the average particle diameter (d1) of the magnetic filler may be 3 nm to 1 mm, 1 µm to 300 µm, 1 µm to 50 µm, or 1 µm to 10 µm.

In addition, the average particle diameter (d2) of the heat dissipation filler may be 10 nm to 10 μm.

Specifically, the average particle diameter (d2) of the heat dissipation filler may be 10 nm to 5 μm.

The magnetic pad according to the embodiment may further satisfy Equation (2) below:

1 ≤ c1/c2 ≤ 200 (2)

In the above formula, c1 and c2 are the contents of the magnetic filler and the heat dissipation filler, respectively.

When the content ratio is within the range, the magnetic property by the magnetic filler and the heat dissipation property by the heat dissipation filler are sufficient, and insulation can also be secured by the magnetic filler being surrounded by the heat dissipation filler.

For example, the c1/c2 ratio may be 1 or more, 10 or more, 20 or more, 50 or more, or 200 or more, and may be 200 or less, 150 or less, 100 or less, or 50 or less. Specifically, the c1/c2 ratio may be 10 to 100, or 30 to 50.

The content of the magnetic filler may be 50 wt% or more, or 70 wt% or more, based on the weight of the magnetic pad. For example, the content of the magnetic filler may be 50 wt% to 95 wt%, 70 wt% to 95 wt%, 70 wt% to 90 wt%, 75 wt% to 90 wt%, based on the weight of the magnetic pad. %, 75 wt% to 95 wt%, 80 wt% to 95 wt%, or 80 wt% to 90 wt%.

In addition, the content of the heat dissipation filler, based on the weight of the magnetic pad, 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, 0.1 wt% to 3 wt%, or 0.1 wt% to 2 wt% can be

Specifically, the magnetic pad may include 50 wt% to 95 wt% of the magnetic filler, and 1 wt% to 10 wt% of the heat dissipation filler, based on the weight of the magnetic pad.

Meanwhile, in order to maximize the magnetic properties and heat dissipation properties of the magnetic pad, the magnetic filler and the heat dissipation filler contained in the magnetic pad may be comprehensively considered between their particle diameters and content.

As an example, the magnetic pad may further satisfy the following equation (3):

2.5 ≤ (d1/d2) / (c1/c2) ≤ 500 (3)

In the above formula, d1 and d2 are the average particle diameters of the magnetic filler and the heat dissipation filler, respectively, and c1 and c2 are the contents of the magnetic filler and the heat dissipation filler, respectively.

When it is within the above range, the ratio of the heat dissipation filler present between the magnetic pillars is maximized, and effective heat dissipation can be realized while preventing eddy currents and improving magnetic properties.

For example, the (d1/d2) / (c1/c2) ratio may be 2.5 or more, 5 or more, 10 or more, 50 or more, 100 or more, or 200 or more, and also 500 or less, 300 or less, 200 or less, or 100 or less. Specifically, the (d1/d2) / (c1/c2) ratio may be 2.5 to 300, 2.5 to 100, 5 to 500, 10 to 500, or 50 to 500.

Accordingly, the magnetic pad may further satisfy the following equation (4):

5 < c3/c4 (4)

In the above formula, c3 is the content of the magnetic filler in which the heat dissipation filler is present between the magnetic fillers, and c4 is the content of the magnetic filler in which the heat dissipation filler is not present between the magnetic fillers.

Specifically, the C3/c4 ratio may be 5 or more, 10 or more, 50 or more, or 100 or more, and more specifically, 5 to 1000, 10 to 1000, 50 to 1000, or 100 to 1000.

magnetic filler

The type of the magnetic filler is not particularly limited as long as it is a metallic magnetic filler. For example, the magnetic filler may include a ferritic, Fe-based nanocrystalline (nanocrystal)-based, Fe-based amorphous (amorphous)-based material.

Specifically, the magnetic filler may include oxide magnetic particles such as ferrite (Ni-Zn-based, Mg-Zn-based, Mn-Zn-based ferrite, etc.); metal magnetic particles such as permalloy, sandust, Fe-Si-Cr alloy and Fe-Si-nanocrystal; or mixtures thereof. More specifically, the magnetic particles may be sandus particles having a Fe-Si-Al alloy composition.

As an example, the magnetic filler may have a composition of Chemical Formula 1 below.

[Formula 1]

Fe _1-abc Si _a X _b Y _c

wherein X is Al, Cr, Ni, Cu, or a combination thereof; Y is Mn, B, Co, Mo, or a combination thereof; 0.01 ≤ a ≤ 0.2, 0.01 ≤ b ≤ 0.1, and 0 ≤ c ≤ 0.05.

heat dissipation filler

The heat dissipation filler is not particularly limited to the type as long as it has both insulating properties and heat dissipation properties. That is, the heat dissipation filler may have high thermal conductivity with high specific resistance.

For example, the specific resistance of the heat dissipation filler may be 10 ¹ Ωm or more, specifically, 10 ⁶ Ωm or more. In addition, the thermal conductivity of the heat dissipation filler may be 5 W/mK or more, specifically, 10 W/mK or more. More specifically, the heat dissipation filler may have ^{a resistivity of 10 6} Ωm to 10 ¹⁶ Ωm and a thermal conductivity of 5 W/mK to 5000 W/mK.

The heat dissipation filler may include a non-carbonous inorganic material. That is, the heat dissipation filler included in the magnetic pad is not a carbon-based filler such as graphite or carbon nanotubes.

For example, the heat dissipation filler may include a ceramic. Specifically, the heat dissipation filler may include at least one selected from the group consisting of alumina, silica, aluminum nitride, and magnesium oxide.

On the other hand, it is preferable that the magnetic pad does not include a conductive heat dissipation filler in order to insulate the magnetic particles. That is, the magnetic pad may not include a conductive heat dissipation filler or may include a small amount. For example, the magnetic pad may not include a carbon-based filler having conductivity, such as graphite particles or carbon nanotubes, or may include only a trace amount. Specifically, the content of the carbon-based filler in the magnetic pad may be less than 1% by weight, less than 0.1% by weight, or less than 0.01% by weight.

polymer resin

The polymer resin may be a curable resin. Specifically, the polymer resin may include a photocurable resin, a thermosetting resin, and/or a high heat-resistant thermoplastic resin, preferably a thermosetting resin.

As a resin capable of exhibiting adhesiveness by being cured in this way, it includes at least one functional group or site that can be cured by heat, such as a glycidyl group, an isocyanate group, a hydroxyl group, a carboxyl group, or an amide group; or at least one functional group or site that can be cured by active energy such as an epoxide group, a cyclic ether group, a sulfide group, an acetal group, or a lactone group resin can be used. Such a functional group or moiety may be, for example, an isocyanate group (-NCO), a hydroxyl group (-OH), or a carboxyl group (-COOH).

Specifically, the curable resin may be exemplified by a polyurethane resin, an acrylic resin, a polyester resin, an isocyanate resin, or an epoxy resin having at least one functional group or site as described above, but is not limited thereto.

As an example, the polymer resin may include a polyurethane-based resin, an isocyanate-based curing agent, and an epoxy-based resin. The guide member may contain the polymer resin in an amount of 5 wt% to 40 wt%, 5 wt% to 20 wt%, 5 wt% to 15 wt%, or 7 wt% to 15 wt%. In addition, the guide member, based on the total weight thereof, as the polymer resin, 6 wt% to 12 wt% of a polyurethane-based resin, 0.5 wt% to 2 wt% of an isocyanate-based curing agent, and 0.3 wt% to 1.5 wt% of an epoxy It may contain a system resin.

Area and thickness of magnetic pad

The magnetic pad may have a large area, specifically 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more. Also, the magnetic pad may have an area of ^{10,000 cm 2 or less.} The large-area magnetic pad may be configured by combining a plurality of unit magnetic pads, and in this case, the area of the unit magnetic pad may be 60 cm ² or more, 90 cm ² , or 95 cm ² to 900 cm ² .

The magnetic pad may be in the form of a magnetic sheet, a magnetic sheet laminate, or a magnetic block.

The thickness of the magnetic sheet may be 15 μm or more, 50 μm or more, 80 μm or more, 15 μm to 150 μm, 15 μm to 35 μm, or 85 μm to 150 μm. Such a magnetic sheet may be manufactured by a method for manufacturing a conventional film or sheet.

The magnetic sheet laminate may be one in which 20 or more magnetic sheets or 50 or more magnetic sheets are laminated. In this case, the magnetic sheet laminate may be a stack of 150 or less magnetic sheets or 100 or less magnetic sheets.

In addition, the thickness of the magnetic block may be 1 mm or more, 2 mm or more, 3 mm or more, or 4 mm or more. In this case, the thickness of the magnetic block may be 30 mm or less, 10 mm or less, or 6 mm or less.

Method for manufacturing magnetic pad

The magnetic pad may be manufactured using a composition in which a metal-based magnetic filler and a heat-dissipating filler having insulation properties are dispersed in a polymer resin. For example, the magnetic pad may be molded into a desired shape by extruding the composition into a sheet or injecting it into a mold.

As an example, the magnetic pad may be molded into a sheet, and specifically, it may be manufactured by a method comprising mixing a magnetic filler, a heat dissipating filler, and a polymer resin, forming a sheet, and drying the magnetic pad. In this case, the magnetic filler, the heat dissipation filler, and the polymer resin may be used in the same type and content as previously exemplified.

Specifically, the magnetic pad comprises the steps of (i) dispersing a magnetic filler and a heat dissipation filler in a polymer resin and a solvent to prepare a slurry; and (ii) forming a sheet using the slurry and then drying the sheet.

More specifically, in the magnetic pad, a magnetic filler and a heat dissipation filler are added to a solvent together with a polymer resin, and dispersed by a disperser (planetary mixer, homo mixer, no-bead mill, etc.) to have a viscosity of about 100 cPs to 10,000 cPs After preparing the composition, the composition is extruded while controlling the speed and temperature to form a sheet having a desired thickness, and the solvent is removed through a dryer to prepare a polymer-type magnetic sheet (PMS). In addition, the dried sheet may be cured by thermal pressure or the like. Specifically, the polymer resin may be cured by thermally pressing the dried sheet at a pressure of 1 MPa to 100 MPa and a temperature of 100°C to 300°C.

As another example, the magnetic pad may be manufactured as a large-area polymer-type magnetic block having a constant thickness by a molding process using a mold.

The molding may be performed by injecting the raw material of the magnetic pad into the mold by injection molding. Specifically, the magnetic pad may be manufactured by mixing a magnetic powder and a polymer resin composition to obtain a raw material composition, and then injecting the raw material composition into a mold by an injection molding machine. In this case, the three-dimensional structure of the magnetic pad may be easily realized by designing the internal shape of the mold as a three-dimensional structure. Such a process is impossible when using a conventional sintered ferrite sheet as a magnetic pad.

magnetic properties

The magnetic pad may have a certain level of magnetic properties in the vicinity of a wireless charging standard frequency of an electric vehicle. The wireless charging standard frequency of the electric vehicle may be less than 100 kHz, specifically 79 kHz to 90 kHz, more specifically about 85 kHz, which is a band distinct from a frequency applied to mobile electronic devices such as cell phones.

The magnetic pad has a high magnetic permeability in a wireless charging frequency band, while a low investment loss, so that the charging efficiency is excellent.

For example, the magnetic permeability of the magnetic pad may be 10 or more, 50 or more, 100 or more, or 150 or more in a frequency band of 79 kHz to 90 kHz. Specifically, the magnetic permeability of the magnetic pad may be 10 to 500, 50 to 300, or 100 to 200 in a 79 kHz to 90 kHz frequency band.

In addition, the investment loss of the magnetic pad of the magnetic pad may be 100 or less, 50 or less, 20 or less, or 10 or less in a frequency band of 79 kHz to 90 kHz. Specifically, the investment loss of the magnetic pad of the magnetic pad may be 1 to 100, 1 to 50, 1 to 20, or 1 to 15 in a frequency band of 79 kHz to 90 kHz.

In addition, the magnetic permeability/loss permeability ratio of the magnetic pad may be 5 or more, 10 or more, or 15 or more in a frequency band of 79 kHz to 90 kHz. Specifically, the magnetic permeability/loss permeability ratio of the magnetic pad may be 10 or more in a frequency band of 79 kHz to 90 kHz. More specifically, the magnetic permeability/loss ratio of the magnetic pad may be 5 to 50, 10 to 40, 10 to 30, or 10 to 20 in a 79 kHz to 90 kHz frequency band.

[Wireless Charging Element]

A wireless charging device according to an embodiment includes the magnetic pad according to the embodiment.

3 is a diagram illustrating a configuration of a wireless charging device according to an embodiment.

Referring to FIG. 3 , the wireless charging element 10 includes a coil 200 including a conductive wire; a metal plate 300 disposed on one surface of the coil 200; and a magnetic pad 100 disposed between the coil 200 and the metal plate 300 .

The wireless charging element 10 may further include a support plate 400 supporting the coil 200 . The material and structure of the support plate may adopt the material and structure of a conventional support plate used for a wireless charging pad. The support plate may have a flat plate structure or a structure in which a groove is dug along a coil shape to fix the coil.

In addition, the wireless charging device 10 includes a spacer for securing a space between the metal plate 300 and the magnetic pad 100 , and components such as the coil 200 , the metal plate 300 , and the magnetic pad 100 . It may further include a housing that protects and properly disposes them.

coil

The conductive wire constituting the coil may include a conductive material, specifically, a conductive metal. More specifically, the conductive wire may include at least one metal selected from the group consisting of copper, nickel, gold, silver, zinc, and tin.

In addition, the conductive wire may have an insulating sheath. For example, the insulating shell may include an insulating polymer resin. Specifically, the insulating shell may include a polyvinyl chloride (PVC) resin, a polyethylene (PE) resin, a Teflon resin, a silicone resin, a polyurethane resin, and the like.

The diameter of the conductive wire may be, for example, in the range of 1 mm to 10 mm, in the range of 1 mm to 5 mm, or in the range of 1 mm to 3 mm.

The conductive wire may be wound in the form of a flat coil. Specifically, the planar coil may include a planar spiral coil. At this time, the shape of the planar coil may be an elliptical shape, a polygonal shape, or a polygonal shape with rounded corners, but is not particularly limited.

The outer diameter of the planar coil may be 5 cm to 100 cm, 10 cm to 50 cm, 10 cm to 30 cm, 20 cm to 80 cm, or 50 cm to 100 cm. As a specific example, the planar coil may have an outer diameter of 10 cm to 50 cm.

In addition, the inner diameter of the planar coil may be 0.5 cm to 30 cm, 1 cm to 20 cm, or 2 cm to 15 cm.

The number of windings of the flat coil may be 5 to 50 times, 10 to 30 times, 5 to 30 times, 15 to 50 times, or 20 to 50 times. As a specific example, the flat coil may be formed by winding the conductive wire 10 to 30 times.

In addition, the distance between the conductive wires in the planar coil shape may be 0.1 cm to 1 cm, 0.1 cm to 0.5 cm, or 0.5 cm to 1 cm.

When it is within the preferred planar coil dimensions and standard ranges as described above, it may be more suitable for fields requiring large-capacity power transmission, such as electric vehicles.

plate

The metal plate is disposed on one surface of the coil.

The metal plate serves to increase the wireless charging efficiency through electromagnetic wave shielding.

The material of the metal plate may be aluminum, and other metal or alloy materials having electromagnetic wave shielding ability may be used.

The thickness of the metal plate may be 0.2 mm to 10 mm, 0.5 mm to 5 mm, or 1 mm to 3 mm. In addition, the area of the metal plate may be 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more.

magnetic pad

The magnetic pad is disposed between the coil and the metal plate.

The magnetic pad may be disposed to be spaced apart from the metal plate by a predetermined interval. For example, the separation distance between the magnetic pad and the metal plate may be 3 mm or more, 5 mm or more, 3 mm to 10 mm, or 4 mm to 7 mm.

Also, the magnetic pad may be disposed to be spaced apart from the coil by a predetermined interval. For example, the separation distance between the magnetic pad and the coil may be 0.2 mm or more, 0.5 mm or more, 0.2 mm to 3 mm, or 0.5 mm to 1.5 mm.

Components and characteristics constituting the magnetic pad included in the wireless charging device are the same as those described for the magnetic pad according to the above-described embodiment.

The magnetic pad according to the embodiment can improve the magnetic properties and heat dissipation properties of the magnetic pad at the same time by simply adding a heat dissipation filler with controlled electrical properties and particle size to the organic-inorganic composite magnetic pad. Accordingly, the magnetic pad according to the embodiment may exhibit additional heat dissipation performance while suppressing heat generation and deterioration of magnetic properties due to aggregation between magnetic fillers and may be manufactured by a simple process.

Accordingly, the wireless charging device including the magnetic pad may be usefully used in an electric vehicle requiring large-capacity power transmission between a transmitter and a receiver. For example, the wireless charging device may be a terminal used for wireless charging of an electric vehicle, that is, a transmitter or a receiver.

[Electric Vehicle]

4 shows an electric vehicle to which a wireless charging device is applied. The electric vehicle may be charged wirelessly in a parking area equipped with a wireless charging system for an electric vehicle.

Referring to FIG. 4 , the electric vehicle 1 according to the embodiment may include the wireless charging device 10 according to the embodiment as a receiver. That is, the wireless charging element may serve as a receiver of wireless charging of the electric vehicle 1 and receive power from the transmitter 22 of wireless charging.

The configuration and characteristics of each component of the wireless charging device included in the electric vehicle are the same as those described in the previous embodiment.

The wireless charging element (receiver) may be provided under the vehicle.

The electric vehicle may further include a battery receiving power from the wireless charging device (receiver). The wireless charging element (receiver) may receive power wirelessly and transmit it to the battery, and the battery may supply power to a driving system of the electric vehicle. The battery may be charged by power transmitted from the wireless charging device (receiver) or other additional wired charging devices.

In addition, the electric vehicle may further include a signal transmitter for transmitting information about charging to the transmitter of the wireless charging system for the electric vehicle. The information about such charging may be charging efficiency such as charging speed, charging degree, and the like.

[Example]

More specific embodiments are described below, but are not limited to the scope of these embodiments.

Materials used in the following examples are as follows.

- Magnetic filler: sandust powder, average particle diameter 65 ㎛

- Heat radiation filler: Al ₂ O ₃ powder, average particle size 2 ㎛

- Polymer resin: contains polyurethane-based resin, epoxy-based resin and isocyanate-based curing agent

- Organic solvent: toluene

Example 1: Preparation of magnetic pad

50 parts by weight of a magnetic filler, 5 parts by weight of a heat dissipation filler, 10 parts by weight of a polymer resin, and 33 parts by weight of an organic solvent were mixed in a mixer at a speed of 40 rpm for 2 hours to prepare a magnetic powder slurry.

The previously prepared magnetic powder slurry was coated on a carrier film by a comma coater, and dried at a temperature of about 110° C. to form a dry magnetic pad. The dried magnetic pad was compression-hardened by a hot press process at a temperature of about 170° C. to obtain a magnetic pad having a thickness of 5 mm.

Comparative Example 1: Preparation of magnetic pad

The same procedure as in Example 1 was repeated, but without adding the heat dissipation filler, a magnetic pad having a thickness of 5 mm was obtained.

Test Example 1: Magnetic properties

Through the impedance analysis equipment, the magnetic permeability and investment loss for the magnetic pad at 85 kHz were measured. The results are summarized in the table below.

division permeability investment loss Permeability / Investment Loss Ratio Example 1 122 8 15 Comparative Example 1 188 20 9

As shown in the table, the magnetic pad of Example 1 had a permeability higher than an appropriate level, but had a significantly lower investment loss than the magnetic pad of Comparative Example 1, and thus had a very high magnetic permeability/investment loss ratio.

Test Example 2: Heat dissipation characteristics

A wireless charging device was manufactured by combining a magnetic pad with a coil, a metal plate, a support plate, and the like, and wireless charging was performed for 30 minutes. At this time, the initial temperature of the magnetic pad and the temperature after 30 minutes of charging were measured, and the results are summarized in the table below.

division initial temperature Temperature after 30 minutes of charging Example 1 25℃ 80℃ Comparative Example 1 25℃ 110℃

As shown in the table, the temperature of the magnetic pad of Example 1 was significantly lower than that of Comparative Example 1 after wireless charging for 30 minutes.

1: electric vehicle,
10: wireless charging element (receiver), 20: wireless charging element (transmitter),
100: a magnetic pad according to an embodiment, 101: a conventional organic-inorganic composite magnetic pad,
110, 210: magnetic filler, 120: heat dissipation filler,
150: conductive network, 200: coil,
300: metal plate, 400: support plate,

Claims (15)

polymer resin;
a metal-based magnetic filler dispersed in the polymer resin; and
and a heat dissipation filler dispersed in the polymer resin and having insulation,
A magnetic pad satisfying the following formula (1):
5 ≤ d1/d2 ≤ 500 (1)
in the above formula
d1 and d2 are the average particle diameters of the magnetic filler and the heat dissipation filler, respectively.
The method of claim 1,
The magnetic pad, wherein the heat dissipation filler has ^{a resistivity of 10 6} Ωm to 10 ¹⁶ Ωm and a thermal conductivity of 5 W/mK to 5000 W/mK.
The method of claim 1,
The magnetic pad, wherein the heat dissipation filler includes a non-carbonous inorganic material.
The method of claim 1,
The magnetic pad, wherein the heat dissipation filler comprises a ceramic.
The method of claim 1,
The heat dissipation filler comprising at least one selected from the group consisting of alumina, silica, aluminum nitride and magnesium oxide, magnetic pad.
The method of claim 1,
The d1/d2 ratio is 10 to 100, the magnetic pad.
7. The method of claim 6,
The d2 is 10 nm to 10 μm, the magnetic pad.
The method of claim 1,
A magnetic pad, wherein the magnetic pad further satisfies the following formula (2):
1 ≤ c1/c2 ≤ 200 (2)
in the above formula
c1 and c2 are the contents of the magnetic filler and the heat dissipation filler, respectively.
The method of claim 1,
The magnetic pad, based on the total weight of the magnetic pad,
50% to 95% by weight of the magnetic filler,
A magnetic pad comprising 1 wt% to 10 wt% of the heat dissipation filler.
The method of claim 1,
A magnetic pad, wherein the magnetic pad further satisfies the following formula (3):
2.5 ≤ (d1/d2) / (c1/c2) ≤ 500 (3)
in the above formula
d1 and d2 are the average particle diameters of the magnetic filler and the heat dissipation filler, respectively,
c1 and c2 are the contents of the magnetic filler and the heat dissipation filler, respectively.
The method of claim 1,
The magnetic pad has a magnetic permeability/loss of investment ratio of 10 or more in a frequency band of 79 kHz to 90 kHz.
polymer resin;
a metal-based magnetic filler dispersed in the polymer resin; and
and a heat dissipation filler dispersed in the polymer resin and having insulation,
and the heat dissipation pillar surrounds the magnetic pillar.
13. The method of claim 12,
The magnetic pad has no direct contact between the magnetic pillars by the heat dissipation pillar.
A wireless charging device comprising the magnetic pad of claim 1 .
15. The method of claim 14,
The wireless charging element is used in an electric vehicle, a wireless charging element.

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