KR102293776B1 - Wireless charging pad, wireless charging device, and electric vehicle comprising same - Google Patents

Abstract

In the wireless charging pad according to an embodiment, charging efficiency and heat dissipation characteristics may be improved together by applying a three-dimensional structure to a magnetic material and utilizing an additional magnetic material. Accordingly, the wireless charging pad and the wireless charging device employing the structure thereof may be usefully used in electric vehicles that require large-capacity power transmission between a transmitter and a receiver.

Description

Wireless charging pad, wireless charging device, and electric vehicle including the same

Embodiments relate to a wireless charging pad, a wireless charging device, and an electric vehicle including the same. More specifically, the embodiment relates to a wireless charging pad with improved charging efficiency by applying a heat dissipation structure, a wireless charging device, and an electric vehicle 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 electronic devices become more mobile, 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.

In a conventional wireless charging pad used for electric vehicles, etc., with reference to FIG. 3 , a magnetic material 300 ′ is disposed adjacent to the coil 200 ′ to improve wireless charging efficiency, and a shield unit 400 ′ for shielding ) is disposed to be spaced apart from the magnetic material 300 ′ by a predetermined interval.

The wireless charging pad generates heat during the wireless charging operation due to the resistance of the coil and the magnetic loss of the magnetic material. In particular, the magnetic material in the wireless charging pad generates heat near the coil with high electromagnetic wave energy density. There was a problem in that the heat was intensified again due to this. However, since such a wireless charging pad is installed in the lower part of the electric vehicle, it is difficult to implement a heat dissipation structure because it adopts a sealed structure for dustproof, waterproof and shock absorption.

Korean Patent Publication No. 2011-0042403

In a conventional wireless charging device, a magnetic material is mainly disposed between a plurality of ferrite sintered sheets between the coil and the shield portion, particularly on one surface close to the coil. Sintered ferrite has a heavy specific gravity, and when the distance between the coil and the shield part gets closer (eg, less than 10 mm), there is a problem that the efficiency rapidly decreases. On the other hand, the thicker the sintered ferrite sheet, the better the charging efficiency and heat generation characteristics, but there is a problem in that the weight increases, so it is generally used in a thickness of 4 to 6 mm. Accordingly, an empty space exists between the sintered ferrite sheet and the shield portion.

In this case, a separate structure such as a spacer is required to maintain the distance between the coil and the shield part and to stably fix the sintered ferrite sheet, and there is a problem in that the cost increases according to the assembly process thereof. In addition, heat is generated from the coil and the sintered ferrite sheet during charging. In particular, the heat generated from the sintered ferrite sheet is difficult to transmit and dissipate to air or spacers having low thermal conductivity properties. Accordingly, the magnetic properties of the sintered ferrite sheet having an elevated temperature are lowered, and the inductance value of the coil is changed accordingly, thereby lowering charging efficiency and causing more severe heat generation.

As a result of research by the present inventors, it was found that charging efficiency and heat dissipation characteristics could be improved by applying a three-dimensional structure to the magnetic material used for the wireless charging pad and utilizing an additional magnetic material having different magnetic properties.

Accordingly, an object of the embodiment is to provide a wireless charging pad, a wireless charging device, and an electric vehicle including the same, in which charging efficiency and heat dissipation characteristics are improved by applying a magnetic material having a three-dimensional structure and utilizing an additional magnetic material.

According to one embodiment, a coil comprising a conductive wire; a shield portion disposed on the coil; and a first magnetic material and a second magnetic material disposed between the coil and the shield, wherein an area corresponding to the coil in the first magnetic material is defined as a first area, and other areas are defined as a second area. When defined as a region, the first region of the first magnetic material has a thicker thickness than the second region, and the second magnetic material has a higher magnetic permeability at 79 kHz to 90 kHz than the first magnetic material. , a wireless charging pad is provided.

According to another embodiment, the housing; a coil disposed within the housing and including a conductive wire; a shield portion disposed on the coil; and a first magnetic material and a second magnetic material disposed between the coil and the shield, wherein an area corresponding to the coil in the first magnetic material is defined as a first area, and other areas are defined as a second area. When defined as a region, the first region of the first magnetic material has a thicker thickness than the second region, and the second magnetic material has a higher magnetic permeability at 79 kHz to 90 kHz than the first magnetic material. , a wireless charging device is provided.

According to another embodiment, an electric vehicle including the wireless charging device according to the embodiment is provided.

According to the above embodiment, by applying a three-dimensional structure to the magnetic material used for the wireless charging pad and having two types of magnetic materials, charging efficiency and heat dissipation characteristics can be improved together.

Specifically, according to the embodiment, by increasing the thickness of the magnetic material in the rear part of the coil where electromagnetic energy is concentrated during wireless charging and lowering the thickness of the magnetic material in the center of the magnetic material having a relatively low electromagnetic energy density, the wireless charging efficiency is increased while in the magnetic material. It can reduce the heat generated. In addition, the introduction of the second magnetic material, which has a higher magnetic permeability compared to the first magnetic material, effectively distributes magnetic flux density and heat dissipation to increase wireless charging efficiency, while dissipating the heat generated from the second magnetic material through the shield unit to dissipate heat dissipation characteristics can also be improved.

Accordingly, the wireless charging pad and the wireless charging device employing the structure thereof may be usefully used in electric vehicles that require large-capacity power transmission between a transmitter and a receiver.

1 shows a configuration diagram of a wireless charging pad according to an embodiment.
2A to 2C are cross-sectional views of a wireless charging device according to an embodiment.
Figure 3 shows the configuration of a conventional wireless charging pad.
4 shows an electric vehicle to which a wireless charging device is applied as a receiver.

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 with reference to 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" a certain component does not exclude other components, unless otherwise stated, means that other components may be further included.

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" and "a" should be construed as meaning including the singular or the plural as interpreted in context.

[Wireless Charging Pad]

1 shows a configuration diagram of a wireless charging pad according to an embodiment.

Referring to FIG. 1 , the wireless charging pad 10 according to an embodiment includes a coil 200 including a conductive wire; a shield unit 400 disposed on the coil 200; It includes a first magnetic material 300 and a second magnetic material 500 disposed between the coil 200 and the shield unit 400, and in the first magnetic material 300 to the coil 200 When a corresponding region is defined as the first region 310 and other regions are defined as the second region 320 , the first region 310 of the first magnetic material 300 is the second region ( 320 ), and the second magnetic material 500 has a higher magnetic permeability at 79 kHz to 90 kHz than the first magnetic material 300 .

Hereinafter, each component of the wireless charging pad will be described in detail.

support plate

The wireless charging pad 10 may further include a support plate 100 for supporting the coil 200 . The material and structure of the support plate may employ 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.

coil

The coil includes a conductive wire.

The conductive wire includes a conductive material. For example, the conductive wire may include a conductive metal. 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. In this case, the planar shape of the 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 within the preferred planar coil dimensions and specifications as described above, it may be suitable for fields requiring large-capacity power transmission, such as electric vehicles.

shield part

The shield part is disposed on the coil.

The shield unit suppresses electromagnetic interference (EMI) that may be generated by leakage of electromagnetic waves to the outside through electromagnetic shielding.

The shield part may be disposed to be spaced apart from the coil by a predetermined interval. For example, a distance between the shield and the coil may be 10 mm or more or 15 mm or more, and specifically, 10 mm to 30 mm, or 10 mm to 20 mm.

The material of the shield part may be, for example, a metal, and thus the shield part may be a metal plate, but is not particularly limited. As a specific example, the material of the shield part may be aluminum, and other metal or alloy materials having electromagnetic wave shielding ability may be used.

The thickness of the shield part 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 shield part may be 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more.

first magnetic material

The first magnetic material is disposed between the coil and the shield unit.

The first magnetic material may be disposed to be spaced apart from the coil by a predetermined interval. For example, the separation distance between the first magnetic material 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.

In addition, the first magnetic material may be disposed to be spaced apart from the shield portion by a predetermined interval. For example, the separation distance between the first magnetic material and the shield portion may be 3 mm or more, 5 mm or more, 3 mm to 10 mm, or 4 mm to 7 mm.

Three-dimensional structure of the first magnetic material

According to the embodiment, charging efficiency and heat dissipation characteristics may be improved by applying a three-dimensional structure to the first magnetic material. That is, when a region corresponding to the coil in the first magnetic material is defined as a first region and other regions are defined as a second region, the first region of the first magnetic material is larger than the second region. have a greater thickness. In this case, in the first magnetic material, the first region and the second region may be integrally formed with each other.

As described above, by increasing the thickness of the magnetic material on the rear side of the coil where electromagnetic energy is concentrated during wireless charging and lowering the thickness of the magnetic material in the center where the electromagnetic energy density is relatively low, the electromagnetic waves concentrated around the coil are effectively focused to improve charging efficiency. Not only can the distance between the coil and the shield part be firmly maintained without a separate spacer, but the material cost and process cost due to the use of the spacer can be reduced.

In the first magnetic material, the first region may have a thickness that is 1.5 times or more thicker than that of the second region. When the thickness ratio is above, it is possible to improve charging efficiency by more effectively focusing electromagnetic waves that are concentrated around the coil, and it is also advantageous for heat generation and weight reduction. Specifically, in the first magnetic material, a thickness ratio of the first region/second region may be 2 or more, 3 or more, or 5 or more. In addition, the thickness ratio may be 100 or less, 50 or less, 30 or less, or 10 or less. More specifically, the thickness ratio may be 1.5 to 100, 2 to 50, 3 to 30, or 5 to 10.

The thickness of the first region of the first magnetic material may be 1 mm or more, 3 mm or more, or 5 mm or more, and may be 30 mm or less, 20 mm or less, or 11 mm or less. In addition, the thickness of the second region of the first magnetic material may be 10 mm or less, 7 mm or less, or 5 mm or less, and may be 0 mm, 0.1 mm or more, or 1 mm or more. Specifically, the first region of the first magnetic material may have a thickness of 5 mm to 11 mm, and the second region may have a thickness of 0 mm to 5 mm.

When the thickness of the second region 320 of the first magnetic material 300 is 0, the first magnetic material 300 may have an empty shape in the second region 320 (eg, a donut). shape). In this case, the first magnetic material can effectively improve charging efficiency even with a smaller area.

Area and thickness of the first magnetic material

The first magnetic material may have a large area, specifically 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more. Also, the first magnetic material may have an area of ^{10,000 cm 2 or less.}

The first magnetic material having a large area may be configured by combining a plurality of unit magnetic materials, in this case, the area of the unit magnetic material is 60 cm ² or more, 90 cm ² , or 95 cm ² to 900 cm ² have.

Alternatively, the first magnetic material may have an empty shape in the second region, and in this case, may have an area of the first region, that is, an area corresponding to the coil.

The first magnetic material may be a magnetic block manufactured by a method such as molding through a mold. For example, the first magnetic material may be molded into a three-dimensional structure through a mold. Such a magnetic sheet may be molded into a three-dimensional structure by mixing magnetic powder and a binder resin and injecting it into a mold by injection molding or the like.

Alternatively, the first magnetic material may be a laminate of magnetic sheets, and for example, 20 or more magnetic sheets, or 50 or more magnetic sheets may be laminated.

Specifically, the magnetic sheet laminate may be one in which one or more additional magnetic sheets are further laminated only in the second region of the first magnetic material. In this case, the thickness of each magnetic sheet may be 80 μm or more, or 85 μm to 150 μm. Such a magnetic sheet may be manufactured by a conventional sheet forming process, such as mixing magnetic powder and a binder resin to form a slurry, then forming and curing the magnetic sheet into a sheet shape.

magnetic powder

The first magnetic material may include a binder resin and magnetic powder dispersed in the binder resin.

Accordingly, in the first magnetic material, since magnetic powders are combined with each other by a binder resin, overall defects in a large area and damage due to impact may be small.

The magnetic powder may be an oxide-based magnetic powder, a metal-based magnetic powder, or a mixed powder thereof. For example, the oxide-based magnetic powder may be a ferrite-based powder, specifically, a Ni-Zn-based, Mg-Zn-based, or Mn-Zn-based ferrite powder. In addition, the metal-based magnetic powder may be a Fe-Si-Al alloy magnetic powder or a Ni-Fe alloy magnetic powder, and more specifically, may be a sandust powder or a permalloy powder.

As an example, the magnetic powder may have a composition of 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.

In addition, the magnetic powder may be a nanocrystalline magnetic powder, for example, may be a Fe-based nanocrystalline magnetic powder, specifically, Fe-Si-Al-based nanocrystalline magnetic powder, Fe-Si-Cr It may be a nanocrystalline magnetic powder based on nanocrystalline or Fe-Si-B-Cu-Nb based nanocrystalline magnetic powder.

The average particle diameter of the magnetic powder may be in the range of about 3 nm to about 1 mm, about 1 μm to 300 μm, about 1 μm to 50 μm, or about 1 μm to 10 μm.

The first magnetic material may include the magnetic powder in an amount of 10 wt% or more, 50 wt% or more, 70 wt% or more, or 85 wt% or more.

For example, the first magnetic material may contain 10 wt% to 99 wt%, 10 wt% to 95 wt%, 50 wt% to 95 wt%, 50 wt% to 92 wt%, 70 wt% to the magnetic powder. 95% by weight, 80% to 95% by weight, or 80% to 90% by weight.

binder resin

As the binder resin, polyimide resin, polyamide resin, polycarbonate resin, acrylonitrile-butadiene-styrene (ABS) resin, polypropylene resin, polyethylene resin, polystyrene resin, polyphenylsulfide (PSS) resin, polyether ether ketone (PEEK) resin, silicone resin, acrylic resin, polyurethane resin, polyester resin, isocyanate resin, epoxy resin and the like may be exemplified, but is not limited thereto.

For example, the binder resin may be a curable resin. Specifically, the binder resin may be a photocurable resin and/or a thermosetting resin, and in particular, may be a resin capable of exhibiting adhesiveness by curing. More specifically, the binder resin may include 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).

The first magnetic material may contain the binder 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, based on the weight of the first magnetic material, as the binder 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 the epoxy-based resin.

Magnetic properties of the first magnetic material

The first magnetic material may have a magnetic property of a certain level in the vicinity of the wireless charging standard frequency of the electric vehicle.

The wireless charging standard frequency of the electric vehicle may be less than 100 kHz, for example, 79 kHz to 90 kHz, specifically 81 kHz to 90 kHz, more specifically about 85 kHz, which is a mobile electronic device such as a mobile phone. It is a band distinct from the applied frequency.

The magnetic permeability in the frequency band of 79 kHz to 90 kHz of the first magnetic material may vary depending on the material, and may be in the range of 5 to 150,000, and in the range of 5 to 300, 500 to 3,500, or 10,000 to 150,000 days depending on the specific material. can In addition, the investment loss in the frequency band of 79 kHz to 90 kHz of the first magnetic material may vary depending on the material, and may be 0 to 50,000 in a wide range, 0 to 1,000, 1 to 100, 100 to 1,000, depending on the specific material , or 5,000 to 50,000.

As a specific example, when the first magnetic material is a polymer-type magnetic block including a magnetic powder and a binder resin, the magnetic permeability in the frequency band of 79 kHz to 90 kHz may be 5 to 130, 15 to 80, or 10 to 50. and the investment loss may be 0 to 20, 0 to 15, or 0 to 5.

Physical properties of the first magnetic material

The first magnetic material may be elongated at a certain rate. For example, the elongation of the first magnetic material may be 0.5% or more. The elongation property is difficult to obtain in a ceramic-based magnetic material that does not apply a polymer, and can reduce damage even when a large-area magnetic material is distorted due to an impact. Specifically, the elongation of the first magnetic material may be 0.5% or more, 1% or more, or 2.5% or more. There is no particular limitation on the upper limit of the elongation, but if the content of the polymer resin is increased to improve the elongation, properties such as inductance of the magnetic material may be deteriorated, so that the elongation is preferably 10% or less.

The first magnetic material has a small rate of change in characteristics before and after impact, and is significantly superior to that of a general ferrite magnetic sheet.

In the present specification, the property change rate (%) before and after the impact of a certain property can be calculated by the following formula. Characteristic change rate (%) = | Property Values Before Impact - Property Values After Impact | / pre-impact property value x 100

For example, the first magnetic material may have an inductance change rate of less than 5% or less than 3% before and after an impact applied by free-falling from a height of 1 m. More specifically, the inductance change rate may be 0% to 3%, 0.001% to 2%, or 0.01% to 1.5%. When within the above range, the inductance change rate before and after the impact is relatively small, so the stability of the magnetic material may be further improved.

In addition, the first magnetic material is free-falling from a height of 1 m and the quality factor (Q factor) change rate before and after the applied impact may be 0% to 5%, 0.001% to 4%, or 0.01% to 2.5%. . When within the above range, the change in properties before and after impact is small, so the stability and impact resistance of the magnetic material can be further improved.

In addition, the first magnetic material may have a resistance change rate of 0% to 2.8%, 0.001% to 1.8%, or 0.1% to 1.0% before and after an impact applied by free falling from a height of 1 m. When within the above range, the resistance value may be well maintained below a certain level even if it is repeatedly applied in an environment to which an actual shock and vibration are applied.

In addition, the first magnetic material may have a rate of change of charging efficiency before and after an impact applied by free falling from a height of 1 m to 0% to 6.8%, 0.001% to 5.8%, or 0.01% to 3.4%. When it is within the above range, the properties of the magnetic material of a large area may be more stably maintained even if an impact or distortion occurs repeatedly.

Magnetic properties of the second magnetic material

The wireless charging pad according to the embodiment further includes a second magnetic material in addition to the first magnetic material.

The second magnetic material may have a magnetic characteristic in a specific range near the wireless charging standard frequency of the electric vehicle.

For example, in the frequency band of 79 kHz to 90 kHz of the second magnetic material, the magnetic permeability may vary depending on the material, and may be in the range of 5 to 150,000, and in the range of 5 to 300, 500 to 3,500, or 10,000 depending on the specific material. to 150,000. In addition, the investment loss in the frequency band of 79 kHz to 90 kHz of the second magnetic material may vary depending on the material, and may be 0 to 50,000 in a wide range, 0 to 1,000, 1 to 100, 100 to 1,000, depending on the specific material , or 5,000 to 50,000.

As a specific example, when the second magnetic material is a ferritic material, the magnetic permeability in the frequency band of 79 kHz to 90 kHz may be 1,000 to 5,000, or 2,000 to 4,000, and the investment loss is 0 to 1,000, 0 to 100, or 0 to 50.

According to the embodiment, the second magnetic material has a higher magnetic permeability at 79 kHz to 90 kHz than the first magnetic material. For example, the difference in permeability between the second magnetic material and the first magnetic material at 79 kHz to 90 kHz may be 100 or more, 500 or more, or 1,000 or more, and specifically 100 to 5,000, 500 to 4,000, or 1,000 to 4,000.

Specifically, the first magnetic material may have a magnetic permeability of 5 to 300 at 79 kHz to 90 kHz, and the second magnetic material may have a magnetic permeability of 1,000 to 5,000 at 79 kHz to 90 kHz.

During wireless charging, the magnetic flux density increases as it approaches the coil, but when a magnetic material is around the coil, the magnetic flux is focused on the magnetic material. will lose Accordingly, when the second magnetic material having a higher magnetic permeability than the first magnetic material is properly disposed, the magnetic flux can be effectively distributed.

Composition and shape of the second magnetic material

The second magnetic material may include an oxide-based magnetic material, a metal-based magnetic material, or a composite material thereof.

For example, the oxide-based magnetic material may be a ferritic material, and a specific chemical formula may be expressed as MOFe ₂ O ₃ (where M is one or more divalent metal elements such as Mn, Zn, Cu, Ni). have. The ferritic material is advantageous in terms of magnetic properties such as magnetic permeability that it is a sintered body. The ferritic material may be manufactured in the form of a sheet or block by mixing raw materials, calcining, pulverizing, mixing this with a binder resin, molding, and firing.

More specifically, the oxide-based magnetic material may be a Ni-Zn-based, Mg-Zn-based, or Mn-Zn-based ferrite. In particular, the Mn-Zn-based ferrite has a temperature of room temperature to 100° C. or higher at a frequency of 79 kHz to 90 kHz. It can exhibit high permeability, low investment loss, and high saturation magnetic flux density over the range.

The Mn-Zn-based ferrite is iron oxide Fe ₂ O ₃ 66 mol% to 70 mol%, ZnO 10 mol% to 20 mol%, MnO 8 mol% to 24 mol%, NiO 0.4 mol% to 2 mol% as a main component. and SiO ₂ , CaO, Nb ₂ O ₅ , ZrO ₂ , SnO and the like as other subcomponents. The Mn-Zn-based ferrite is pulverized by mixing the main component in a predetermined molar ratio, calcining in the air at a temperature of 800 ° C. to 1100 ° C. for 1 hour to 3 hours, and then adding sub-components, and thus a binder such as polyvinyl alcohol (PVA) After mixing an appropriate amount of the resin and press-molding using a press, the temperature is raised to 1200° C. to 1300° C. and calcined for 2 hours or more, thereby producing a sheet or block form. Thereafter, it is cut to a required size through processing using a wire saw or a water jet, if necessary.

In addition, the metal-based magnetic material may be a Fe-Si-Al alloy magnetic material or a Ni-Fe alloy magnetic material, and more specifically, may be sandust or permalloy. In addition, the second magnetic material may include a nanocrystalline magnetic material, for example, a Fe-based nanocrystalline magnetic material, specifically, a Fe-Si-Al-based nanocrystalline magnetic material, Fe-Si- It may include a Cr-based nanocrystalline magnetic material, or a Fe-Si-B-Cu-Nb-based nanocrystalline magnetic material. When the nanocrystalline magnetic material is applied as the second magnetic material, the higher the distance from the coil, the lower the resistance (Rs) even if the inductance (Ls) of the coil is lowered, so that the quality factor (Q factor: Ls) of the coil /Rs) can be increased to improve charging efficiency and reduce heat generation.

The second magnetic material may be composed of a magnetic material different from the first magnetic material. As a specific example, the first magnetic material may include a Fe-Si-Al-based alloy magnetic material, and the second magnetic material may include Mn-Zn-based ferrite. The combination of the first magnetic material and the second magnetic material is advantageous in that the second magnetic material has a higher magnetic permeability at 79 kHz to 90 kHz than the first magnetic material.

The second magnetic material may have a sheet form or a block form.

The thickness of the second magnetic material may be 0.5 mm to 5 mm, specifically, 0.5 mm to 3 mm, 0.5 mm to 2 mm, or 1 mm to 2 mm.

The second magnetic material may have the same area as the first magnetic material or may have a different area.

For example, the second magnetic material may have the same large area as the first magnetic material. Specifically, the area of the second magnetic material may be 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more. Also, the area of the second magnetic material ^{may be 10,000 cm 2} or less.

Alternatively, the second magnetic material may have a smaller area than the first magnetic material. For example, when the second magnetic material is disposed only in the first area of the first magnetic material, the second magnetic material may have an area corresponding to the area of the first area. Also, according to this, the second magnetic material may be disposed to correspond to the area in which the coil exists, and may have an area corresponding to the area of the coil. In this case, the second magnetic material can effectively improve charging efficiency and heat dissipation characteristics even with a small area.

Placement of the second magnetic material

The second magnetic material may be disposed on the first region, the second region, or at least a portion thereof.

As an example, the second magnetic material may be disposed in the first region. Accordingly, a high magnetic flux density around the coil can be effectively dispersed, and charging efficiency can be increased compared to the case of using the first magnetic material alone.

Alternatively, the second magnetic material may be disposed over at least a portion of the first region and the second region.

In addition, the second magnetic material may be disposed to be coupled to or separated from the first magnetic material. As shown in FIG. 2A , the second magnetic material 500 may be disposed between the shield unit 400 and the first magnetic material 300 . As described above, by disposing the second magnetic material having a higher magnetic permeability than the first magnetic material close to the shield part, it is possible to effectively disperse the high magnetic flux density around the coil, and when the first magnetic material is used alone Compared to the above, it is possible to not only increase the charging efficiency but also effectively dissipate the heat that is concentrated in the vicinity of the coil of the first magnetic material.

In this case, at least a portion of the second magnetic material may contact the shield portion. Accordingly, heat generated from the second magnetic material may be effectively discharged through the shield unit. For example, when the second magnetic material is in the form of a sheet, an entire surface of the second magnetic material may contact the shield portion. Specifically, the second magnetic material may be attached to one surface of the shield unit facing the first magnetic material. The second magnetic material is attached to one surface of the shield unit with a thermally conductive adhesive, thereby further enhancing the heat dissipation effect. The thermally conductive adhesive may include a thermally conductive material such as a metal-based, carbon-based, or ceramic-based adhesive, for example, an adhesive resin in which thermally conductive particles are dispersed.

In this case, the second magnetic material may also contact the first magnetic material. For example, the second magnetic material may be attached to the first region of the first magnetic material.

Alternatively, the second magnetic material may be disposed to be spaced apart from the first magnetic material by a predetermined distance. For example, the separation distance between the first magnetic material and the second magnetic material is 1 mm or more, 2 mm or more, 1 mm to 10 mm, 2 mm to 7 mm, 3 mm to 5 mm, or 5 mm to 10 mm can be

As shown in FIG. 2B , the first magnetic material 300 may have a groove on the surface facing the shield unit 400 , and the second magnetic material 500 may be inserted into the groove.

In this case, since the first magnetic material may serve as a housing of the second magnetic material, a separate adhesive or structure for fixing the second magnetic material may not be required. In particular, since the first magnetic material can be molded into a three-dimensional structure through a mold using a polymer-type magnetic material using magnetic powder and a binder resin, a groove for inserting the second magnetic material can be easily formed.

In this case, at least a portion of the first magnetic material and the second magnetic material may contact the shield unit 400 . Accordingly, heat generated from the first magnetic material and/or the second magnetic material may be effectively discharged through the shield unit.

The depth of the groove formed in the first magnetic material may be the same as or different from the thickness (height) of the second magnetic material. When the depth of the groove and the thickness of the second magnetic material are the same, the first magnetic material and the second magnetic material may contact the shield part at the same time. Alternatively, when the depth of the groove is smaller than the thickness of the second magnetic material, only the second magnetic material may contact the shield portion. Conversely, when the depth of the groove is greater than the thickness of the second magnetic material, only the first magnetic material may contact the shield portion.

As shown in FIG. 2C , the second magnetic material 500 may be disposed to be embedded in the first magnetic material 300 .

Even in this case, since the first magnetic material may serve as a housing of the second magnetic material, a separate adhesive or structure for fixing the second magnetic material may not be required. In particular, since the first magnetic material can be molded into a three-dimensional structure through a mold using a magnetic polymer type magnetic material using magnetic powder and a binder resin, a structure for embedding the second magnetic material can be easily formed.

In this case, at least a portion of the first magnetic material may contact the shield unit. Accordingly, heat generated from the first magnetic material may be effectively discharged through the shield unit.

[Wireless charging device]

2A to 2C, the wireless charging device 11 according to an embodiment includes a housing 600; a coil 200 disposed within the housing 600 and including a conductive wire; a shield unit 400 disposed on the coil 200; and a first magnetic material 300 and a second magnetic material 500 disposed between the coil 200 and the shield unit 400, and in the first magnetic material 300, the coil 200 When a region corresponding to , is defined as the first region 310 , and other regions are defined as the second region 320 , the first region 310 of the first magnetic material 300 is the second region It has a thicker thickness than that of 320 , and has a high magnetic permeability at 79 kHz to 90 kHz compared to the first magnetic material 300 .

The housing allows components such as the coil, the shield unit, and the magnetic material to be properly arranged and assembled. The material and structure of the housing may adopt the material and structure of a typical housing used in a wireless charging device.

The wireless charging device according to the embodiment may further include a support plate for supporting the coil. The configuration and characteristics of the support plate, the coil, the shield part, and the magnetic material of the wireless charging device are as described above.

In addition, the wireless charging device according to the embodiment may further include a spacer for securing a space between the shield unit and the magnetic material. The material and structure of the spacer may adopt the material and structure of a typical housing used in a wireless charging device.

The wireless charging device may improve charging efficiency and heat dissipation characteristics by applying a three-dimensional structure to a magnetic material. Accordingly, the wireless charging device may be usefully used in an electric vehicle that requires large-capacity power transmission between a transmitter and 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 an embodiment includes the wireless charging device according to the embodiment as a receiver 21 . The wireless charging device may serve as a receiver 21 for wireless charging of the electric vehicle 1 and receive power from a transmitter 22 for wireless charging.

Specifically, the electric vehicle includes a wireless charging device, and the wireless charging device includes a housing; a coil disposed within the housing and including a conductive wire; a shield portion disposed on the coil; and a first magnetic material and a second magnetic material disposed between the coil and the shield, wherein an area corresponding to the coil in the first magnetic material is defined as a first area, and other areas are defined as a second area. When defined as a region, the first region of the first magnetic material has a greater thickness than the second region, and the second magnetic material has a higher magnetic permeability at 79 kHz to 90 kHz than the first magnetic material. .

The configuration and characteristics of each component of the wireless charging device included in the electric vehicle are as described above.

The wireless charging device may be provided under the vehicle.

The electric vehicle may further include a battery receiving power from the wireless charging device. The wireless charging device 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 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 state, and the like.

1: electric vehicle, 10, 10': wireless charging pad,
11: wireless charging device,
21: receiver, 22: transmitter,
100, 100': support plate, 200, 200': coil,
300: a first magnetic material, 300': a magnetic material,
310: a first area, 320: a second area,
400, 400': a shield unit, 500: a second magnetic material,
600: housing.

Claims (15)

a coil comprising a conductive wire;
a shield portion disposed on the coil; and
A first magnetic material and a second magnetic material disposed between the coil and the shield portion,
When a region corresponding to the coil in the first magnetic material is defined as a first region and other regions are defined as a second region, the first region of the first magnetic material is thicker than the second region. have a thickness,
The second magnetic material has a high permeability at 79 kHz to 90 kHz compared to the first magnetic material, and the first magnetic material and the second magnetic material have a magnetic permeability difference of 500 or more at 79 kHz to 90 kHz, wireless charging pad .
The method of claim 1,
In the first magnetic material, the first region has a thickness of 1.5 times or more thicker than that of the second region, the wireless charging pad.
The method of claim 1,
The first magnetic material comprises a binder resin and magnetic powder dispersed in the binder resin, wireless charging pad.
The method of claim 1,
The first magnetic material has a magnetic permeability of 5 to 300 at 79 kHz to 90 kHz, and the second magnetic material has a magnetic permeability of 1,000 to 5,000 at 79 kHz to 90 kHz, wireless charging pad.
delete The method of claim 1,
The first magnetic material includes a Fe-Si-Al-based alloy magnetic material,
The second magnetic material comprises a Mn-Zn-based ferrite, wireless charging pad.
a coil comprising a conductive wire;
a shield portion disposed on the coil; and
A first magnetic material and a second magnetic material disposed between the coil and the shield portion,
When a region corresponding to the coil in the first magnetic material is defined as a first region and other regions are defined as a second region, the first region of the first magnetic material is thicker than the second region. have a thickness,
The second magnetic material has a high permeability at 79 kHz to 90 kHz compared to the first magnetic material,
The second magnetic material is disposed in the first area, wireless charging pad.
8. The method of claim 7,
The second magnetic material is disposed between the shield portion and the first magnetic material, wireless charging pad.
9. The method of claim 8,
At least a portion of the second magnetic material is in contact with the shield portion, the wireless charging pad.
8. The method of claim 7,
The first magnetic material has a groove on the surface facing the shield,
The second magnetic material is disposed to be inserted into the groove, wireless charging pad.
11. The method of claim 10,
At least a portion of the first magnetic material and the second magnetic material is in contact with the shield portion, the wireless charging pad.
8. The method of claim 7,
The second magnetic material is disposed to be embedded in the inside of the first magnetic material, wireless charging pad.
13. The method of claim 12,
At least a portion of the first area of the first magnetic material is in contact with the shield portion, the wireless charging pad.
housing;
a coil disposed within the housing and including a conductive wire;
a shield portion disposed on the coil; and
A first magnetic material and a second magnetic material disposed between the coil and the shield portion,
When a region corresponding to the coil in the first magnetic material is defined as a first region and other regions are defined as a second region, the first region of the first magnetic material is thicker than the second region. have a thickness,
The second magnetic material has a high magnetic permeability at 79 kHz to 90 kHz compared to the first magnetic material, and the first magnetic material and the second magnetic material have a magnetic permeability difference of 500 or more at 79 kHz to 90 kHz, a wireless charging device .
An electric vehicle comprising the wireless charging device of claim 14 .

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