KR102442546B1 - Wireless charging device and vehicle comprising same - Google Patents

Abstract

The wireless charging device according to an embodiment uses two or more types of hybrid magnetic parts having different magnetic permeability, but by disposing a magnetic part having a higher magnetic permeability in the center of the magnetic part, heat can be effectively dispersed, thereby It is possible to further improve charging efficiency and heat reduction characteristics during charging.
Therefore, the wireless charging device can be usefully used in electric vehicles that require large-capacity power transmission between a transmitter and a receiver.

Description

Wireless charging device and means of transportation including the same

The embodiment relates to a wireless charging device and a mobile means including the same. More specifically, the embodiment relates to a wireless charging device with improved charging efficiency by applying a structure capable of effectively dissipating heat, and a moving means including the same.

Recently, as interest in electric vehicles has rapidly increased, 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 under test operation are starting to stand out in Europe, and in Japan, car manufacturers and electric power companies are piloting electric vehicles and charging stations.

In a conventional wireless charging device used for electric vehicles, etc., a magnetic part is disposed adjacent to a coil part to improve wireless charging efficiency, and a shield part (metal plate) for shielding is disposed spaced apart from the magnetic part by a predetermined interval.

The wireless charging device generates heat by the resistance of the coil part and the magnetic loss of the magnetic part during the wireless charging operation. In particular, the magnetic part in the wireless charging device generates heat in a portion close to the coil part with high electromagnetic wave energy density, and the generated heat changes the magnetic properties of the magnetic part to cause an impedance mismatch between the transmitting pad and the receiving pad, and the charging efficiency is lowered. As a result, there was a problem in that the heat was intensified again.

In particular, in the conventional wireless charging device, the magnetic part is mainly disposed between the sintered ferrite sheet and the coil part and the shield part, especially on one surface close to the coil part. The sintered ferrite sheet has low impact resistance and heavy specific gravity, and when it is placed close to the coil part, heat is generated from the coil part and the sintered ferrite sheet during charging. Alternatively, it is difficult to transmit and dissipate heat to the spacer part. Accordingly, the sintered ferrite sheet having an elevated temperature may have a problem in that the magnetic properties are lowered and the inductance value of the coil portion is changed accordingly, thereby lowering charging efficiency and causing more severe heat generation.

Korean Patent Publication No. 2011-0042403

The present invention is devised to solve the problems of the prior art.

The technical problem to be solved by the present invention is to use two or more types of hybrid magnetic parts having different permeability, but by disposing a magnetic part having a higher magnetic permeability in the center of the magnetic part, heat can be effectively dispersed, Accordingly, it is to provide a wireless charging device capable of improving charging efficiency and heat reduction characteristics during wireless charging.

Another technical problem to be solved by the present invention is to provide a moving means including the wireless charging device.

According to one embodiment, the coil unit; and a magnetic part disposed on the coil part, wherein the magnetic part includes a first magnetic part and a second magnetic part, and the second magnetic part is located in the center of the magnetic part, and the entire surface or the circumferential surface of the second magnetic part is Surrounded by the first magnetic portion, the second magnetic portion of the magnetic permeability is higher than the magnetic permeability of the first wireless charging device is provided.

According to another embodiment, a mobile means including a wireless charging device is provided.

According to the embodiment, two or more hybrid (hybrid) type magnetic parts having different permeability are used, but by arranging a magnetic part having a higher magnetic permeability in the center of the magnetic part, the magnetic flux focused during wireless charging, the magnetic flux distribution is relatively more A small amount can be dispersed in the central direction. As a result, it is possible to effectively disperse magnetic flux and heat, thereby effectively improving heat reduction characteristics and wireless charging efficiency during wireless charging.

Therefore, the wireless charging device may be usefully used in a moving means such as an electric vehicle that requires a large-capacity power transmission between a transmitter and a receiver.

1 shows an exploded perspective view of a wireless charging device according to each embodiment.
Figure 2 shows a perspective view of the wireless charging device according to the embodiment.
Figure 3a shows a cross-sectional view of the wireless charging device according to the embodiment.
3B to 3D are cross-sectional views of wireless charging devices according to various embodiments.
4 is a diagram for defining a structure of a second magnetic unit included in the wireless charging device.
5 is a cross-sectional view of the wireless charging device of Examples 1 and 2, and Comparative Examples 1 to 3;
6 is a graph showing the charging efficiency of the wireless charging device according to the charging holding time of Example 1 and Comparative Example 1.
7 is a graph showing the exothermic temperature according to the charge holding time of Example 1 and Comparative Example 1;
8 illustrates a process of forming a magnetic part through a mold according to an exemplary embodiment.
9 illustrates a moving means (electric vehicle) having a wireless charging device according to an embodiment.

Hereinafter, specific embodiments for implementing the spirit of the present invention will be described in detail with reference to the drawings.

In addition, in the description of the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated, and the size of each component does not fully reflect the actual size.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In this specification, like reference numerals refer to like elements.

In this specification, a component described as being formed above or below another component means that a component is formed directly above or below another component or indirectly through another component. include

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

Also, the meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and other specific characteristic, region, integer, step, operation, element, component and It does not exclude the presence or addition of/or groups.

In addition, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in the present 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.

[Wireless charging device]

1 is an exploded perspective view of a wireless charging device according to an embodiment, FIG. 2 is a perspective view of a wireless charging device according to the embodiment, and FIG. 3A is a cross-sectional view of a wireless charging device according to the embodiment. . Also, FIGS. 3B to 3D are cross-sectional views of various wireless charging devices.

The drawings shown in FIGS. 1 to 3 are illustratively shown according to embodiments, and may be variously changed as long as the effects of the present invention are not impaired.

Referring to FIG. 1 , a wireless charging device 10 according to an embodiment includes a coil unit 200 ; a magnetic part disposed on the coil part 200 , the magnetic part includes a first magnetic part 300 and a second magnetic part 500 , and the second magnetic part 500 is a central part of the magnetic part is located, the entire surface or the circumferential surface of the second magnetic part 500 is surrounded by the first magnetic part 300 , and the magnetic permeability of the second magnetic part 500 is the first magnetic part 300 . higher than the permeability of

In general, in the case of a wireless charging device including a coil part and a magnetic part, when measuring magnetic flux density, the magnetic flux is concentrated in a part corresponding to the coil part, so that the magnetic flux density is high. For example, since there is no coil in the center of the magnetic part, the magnetic flux density is measured to be relatively low. In this case, the magnetic flux is not evenly distributed, so heat is intensively generated in the portion corresponding to the heating imbalance, that is, the coil portion with high magnetic flux density. As a result, charging efficiency may be lowered, and heat generation may intensify again.

Accordingly, according to one embodiment of the present invention, two or more types of hybrid magnetic units (including the first magnetic unit and the second magnetic unit) having different magnetic permeability are used, and in this case, a first magnetic unit having higher magnetic permeability than the first magnetic unit is used. By arranging the two magnetic units at the center of the magnetic unit, the magnetic flux that is focused during wireless charging can be dispersed in the direction of the center having a relatively smaller magnetic flux distribution. Therefore, by lowering the magnetic flux density in the part corresponding to the coil part and increasing the magnetic flux density in the center where there is no coil part, the distribution of magnetic flux and heat is evenly distributed, thereby effectively improving heat reduction characteristics and wireless charging efficiency during wireless charging. have.

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

coil part

A wireless charging device according to an embodiment of the present invention includes a coil unit through which an alternating current flows to generate a magnetic field.

The coil unit may include 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 one or more metals 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, 1 mm to 10 mm, 2 mm to 7 mm, or 3 mm to 5 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 addition, 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 1 to 50 times, 5 to 30 times, 5 to 20 times, or 7 to 15 times. As a specific example, the flat coil may be formed by winding the conductive wire 7 to 15 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 dimension and specification range as described above, it may be suitable for a field requiring large-capacity power transmission, such as an electric vehicle.

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

magnetic part

The magnetic part may form a magnetic path of a magnetic field generated around the coil part, and is disposed between the coil part and the shield part.

Referring back to FIG. 1 , in the wireless charging device 10 , the magnetic part has a first magnetic part 300 and a second magnetic part 500 having a higher magnetic permeability than that of the first magnetic part 300 . Including, the second magnetic part 500 may be located in the center of the magnetic part, and the entire surface or the circumferential surface of the second magnetic part 500 may be surrounded by the first magnetic part 300 .

In this case, referring to FIG. 4 , the entire surface of the second magnetic part 500 may mean the entire surface including the upper surface 510 , the lower surface 520 , and the circumferential surface 530 of the second magnetic part. . In addition, the circumferential surface 530 of the second magnetic part 500 is a portion obtained by subtracting the upper surface 510 and the lower surface 520 from the entire surface of the second magnetic part, specifically, in the case of FIG. means two pairs of side surfaces (front, rear, left and right sides), and in the case of (b) of FIG. 4 may mean a cylindrical surface. Although the entire surface or circumferential surface of the second magnetic part 500 has been described as an example in the case of a hexahedron and a cylindrical shape, the shape of the second magnetic part 500 may vary.

According to an embodiment of the present invention, by arranging the second magnetic part 500 having a higher magnetic permeability than the first magnetic part 300 in the center of the magnetic part, the magnetic flux focused during wireless charging is relatively distributed It can be dispersed in the direction of the center with fewer ions, thereby reducing the heating temperature during wireless charging, thereby further improving charging efficiency.

If only one of the first magnetic part and the second magnetic part is applied, or if the arrangement of the first magnetic part and the second magnetic part deviate from the embodiment of the present invention, the magnetic part in the wireless charging device includes a coil part with high electromagnetic wave energy density and A lot of heat is generated in the corresponding part, and the generated heat changes the magnetic properties of the magnetic part and causes an impedance mismatch between the transmitter and the receiver, which lowers the charging efficiency, which intensifies heat generation again, and causes deformation and damage of the device structure. can happen

According to an embodiment of the present invention, when the coil unit 200 receives wireless power from the outside, more heat may be generated in the second magnetic unit 500 than in the first magnetic unit 300 . That is, the amount of heat generated by the second magnetic part 500 may be higher than that of the first magnetic part 300 .

Since the hybrid magnetic part has different magnetic properties and heat generation, depending on the method of arranging and combining them, the magnetic flux concentration during wireless charging can be distributed in the desired direction by using the tendency of the magnetic flux density to increase in the order of the magnetic permeability. And, it is possible to effectively reduce the heating temperature by using the tendency that the amount of heating increases in proportion to the amount of magnetic flux and the size of the investment loss, thereby improving charging efficiency.

Therefore, according to an embodiment of the present invention, by arranging the second magnetic part 500 having a greater magnetic permeability and heating value during wireless charging compared to the first magnetic part 300 in the center of the magnetic part, magnetic flux and heat are reduced. It is possible to effectively disperse and reduce the heating temperature of the magnetic part, thereby increasing the wireless charging efficiency. In the wireless charging device according to an embodiment of the present invention, the magnetic unit may improve the heat reduction effect by having a temperature in a specific range or a temperature increase tendency in a specific range when the coil unit receives wireless power from the outside.

Specifically, the heating temperature of the lower surface of the magnetic part when the magnetic part wireless power having a frequency of 85 kHz and an output of 6.6 kW is transmitted to the coil part for 15 minutes is T ₁₅ , and the wireless power is transmitted for 30 minutes When the exothermic temperature of the lower surface of the magnetic part when it becomes T ₃₀ , it may be further increased from T ₁₅ to T ₃₀ to 30 ℃ or less, for example, 28 ℃ or less, 27 ℃ or less.

If the T ₁₅ to T ₃₀ is further increased to more than 30° C., the magnetic flux and heat generation are not uniformly dispersed, so that the heat generation temperature rapidly rises, thereby reducing charging efficiency. In particular, the heating temperature may further increase during fast charging and high-power wireless charging, and in this case, safety problems such as damage to the wireless charging device and possible destruction of the power conversion circuit may cause restrictions on usability or a sharp decrease in charging efficiency. have.

The T ₁₅ may be 40 °C to 65 °C, for example 45 °C to 63 °C, for example 50 °C to 62 °C.

The T ₃₀ may be 50 °C to 95 °C, for example 55 °C to 92 °C, for example 60 °C to 89 °C.

When T ₁₅ and T ₃₀ respectively satisfy the above ranges, charging efficiency and heat reduction characteristics may be maximized.

On the other hand, when only one of the first magnetic part and the second magnetic part is used, or the arrangement of the first magnetic part and the second magnetic part is out of the embodiment of the present invention, the heating temperature during fast charging and high-power wireless charging may be increased. In this case, safety problems such as damage to the wireless charging device and the possibility of breaking the power conversion circuit may cause restrictions on usability or reduce charging efficiency.

According to an embodiment of the present invention, the wireless charging device is magnetic when, in the SAE J2954 WPT2 Z2 class Standard TEST charging efficiency measurement condition, wireless power having a frequency of 85 kHz and an output of 6.6 kW is transmitted to the coil unit for 30 minutes. The negative surface temperature was measured. In the SAE J2954 WPT2 Z2 class Standard TEST, Society of Automotive Engineers (SAE) J2954 can produce performance, interoperability, and rated output for each capacity of a wireless power transmission system using magnetic induction for electric vehicles. It is a standard that includes various contents such as vertical and horizontal separation distance standards, communication methods between transmitting and receiving pads, operating frequency, EMI (Electromagnetic Interface)/EMC (Electromagnetic Compatibility), and stability. Since this standard provides not only the system performance but also the specification of the transmission/reception pad for each capacity group, most automobile manufacturers follow the configuration and size of the transmission/reception pad suggested in the standard when manufacturing the transmission/reception pad.

The surface temperature of the magnetic part is measured on the lower surface of the magnetic part using T/GUARD 405-SYSTEM manufactured by Qualitrol. Specifically, the surface temperature of the magnetic part is measured based on the center (maximum heating temperature, T) of the first magnetic part, which is a position corresponding to the coil part (see FIG. 5 ).

Meanwhile, the second magnetic part has a thermal conductivity of 0.1 W/m·K to 6 W/m·K, 0.5 W/m·K to 5 W/m·K, or 1 W/m·K compared to the first magnetic unit. K to 4 W/m·K may be higher. Since the second magnetic part having higher thermal conductivity than the first magnetic part is located in the center of the magnetic part, the heat generated during wireless charging is effectively dispersed through the uniform distribution of magnetic flux, and the durability against external shock or distortion is improved. can do it

In addition, by adjusting the amount (volume) used for each magnetic part in consideration of the magnetic properties and physical properties of the two or more kinds of magnetic parts, it is possible to improve the impact resistance and reduce the manufacturing cost without impairing charging efficiency. For example, the first magnetic part may have a volume 2 to 9.5 times larger than that of the second magnetic part.

Hereinafter, the first magnetic part and the second magnetic part will be described in detail.

first magnetic part

Type of first magnetic part

The first magnetic part may include a magnetic powder and a binder resin.

Accordingly, since the magnetic powders are combined with each other by the binder resin, the first magnetic part may have fewer defects and less damage due to impact in a large area.

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 sendust 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 part 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 portion contains 10 wt% to 99 wt%, 10 wt% to 95 wt%, 50 wt% to 95 wt%, 50 wt% to 92 wt%, 70 wt% to 95 wt% of the magnetic powder. weight %, 80% to 95% by weight, or 80% to 90% by weight.

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 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 moiety 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 part 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 part, 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 an epoxy-based resin.

Structural features of the first magnetic part

The first magnetic part is disposed between the coil part and the shield part.

The first magnetic part may be disposed to be spaced apart from the coil part by a predetermined interval. For example, the separation distance between the first magnetic part and the coil part may be 0.2 mm or more, 0.5 mm or more, 0.2 mm to 3 mm, or 0.5 mm to 2 mm.

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

According to an embodiment of the present invention, the first magnetic part may have a three-dimensional structure, and in this case, charging efficiency and heat dissipation characteristics may be improved.

1 and 3A , the first magnetic unit 300 may be disposed in a portion (outer portion) corresponding to a portion in which the coil unit 200 is disposed. That is, the first magnetic part 300 having a relatively lower magnetic permeability than the second magnetic part 500 may be disposed in a portion where the coil part 200 in which electromagnetic energy is concentrated is disposed.

In addition, the first magnetic portion may include an outer portion corresponding to a portion on which the coil portion is disposed; and a central portion surrounded by the outer portion, wherein a thickness of the outer portion may be greater than a thickness of the central portion. In this case, in the first magnetic part, the outer part and the central part may be integrally formed with each other.

In addition, referring to FIG. 3B , the first magnetic part may include an outer part corresponding to a part where the coil part is disposed; and a central portion surrounded by the outer portion, wherein the center (central portion) of the central portion does not include the first magnetic portion so that the second magnetic portion is inserted, and the first magnetic portion surrounds the entire surface of the second magnetic portion. Additional can be placed. Similarly, in the first magnetic part, the outer part and the central part may be integrally formed with each other.

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

Also, with reference to FIGS. 3C and 3D , at least a portion of the magnetic part may not contact the shield part ( FIG. 3C ), or at least a portion of the magnetic part may contact the shield part ( FIG. 3D ). When at least a portion of the magnetic portion contacts the shield portion, at least a portion of the first magnetic portion and the second magnetic portion may contact the shield portion. Accordingly, heat generated in the first magnetic part and/or the second magnetic part may be effectively discharged through the shield part.

The thickness of the first magnetic part 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 center of the first magnetic part 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 outer portion of the first magnetic portion may have a thickness of 5 mm to 11 mm, and the central portion may have a thickness of 0 mm to 5 mm.

When the thickness of the center of the first magnetic portion is 0, the first magnetic portion may have an empty shape in the center (eg, a donut shape). In this case, the charging efficiency can be effectively improved even with a smaller area of the first magnetic part.

Meanwhile, the first magnetic part may have a large area, and specifically, may have an area of 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more. Also, the first magnetic part may have an area of 10,000 cm ² or less.

The large-area first magnetic part may be configured by combining a plurality of unit magnetic parts, and in this case, the area of the unit magnetic part may be 60 cm ² or more, 90 cm ² , or 95 cm ² to 900 cm ² .

Alternatively, the first magnetic part may have an empty shape in the center, and in this case, the first magnetic part may have an area of the outer part, that is, an area corresponding to the coil part or larger.

The first magnetic part may be a magnetic block manufactured by a method such as molding through a mold. For example, the first magnetic part may be molded into a three-dimensional structure through a mold. The 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.

Specifically, the molding may be performed by injecting the raw material of the magnetic part into the mold by injection molding. More specifically, the magnetic part is manufactured by mixing magnetic powder and a polymer resin composition to obtain a raw material composition, and then injecting the raw material composition 701 into the mold 703 by an injection molding machine 702 as shown in FIG. 8 . can be In this case, by designing the internal shape of the mold 703 as a three-dimensional structure, the three-dimensional structure of the magnetic part can be easily implemented. Such a process may be difficult when an existing sintered ferrite sheet is used as a magnetic part.

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

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 properties of the first magnetic part

The first magnetic part may have a magnetic characteristic of a certain level in the vicinity of a 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 85 kHz frequency band of the first magnetic part may vary depending on the material, but may be, for example, 5 to 500, for example, 5 to 400, for example, 5 to 300, or for example, 10 to 300. have.

When the first magnetic material is a polymer-type magnetic block including magnetic powder and a binder resin, the magnetic permeability in the frequency band of 79 kHz to 90 kHz is 5 to 500, 5 to 400, 5 to 200, 5 to 130, 15 to 80, or 10 to 50, and the investment loss may be 0 to 50, 0 to 20, 0 to 15, or 0 to 5.

Physical properties of the first magnetic part

The first magnetic part may be elongated at a certain rate. For example, the elongation of the first magnetic part may be 0.5% or more. The elongation property is difficult to obtain in a ceramic magnetic part to which a polymer is not applied, and damage can be reduced even when a large-area magnetic part is distorted due to an impact. Specifically, the elongation of the first magnetic part 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 part may be deteriorated, so that the elongation is preferably 10% or less.

The first magnetic part 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 characteristic change rate (%) before and after the impact of a certain characteristic may be calculated by the following formula.

Characteristic change rate (%) = | Property Values Before Impact - Property Values After Impact | / property value before impact x 100

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

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

In addition, the resistance change rate before and after the impact applied by free-falling from a height of 1 m to the first magnetic part may be 0% to 2.8%, 0.001% to 1.8%, or 0.1% to 1.0%. When it is 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 charge efficiency change rate before and after the impact applied by free-falling from a height of 1 m to the first magnetic part may be 0% to 6.8%, 0.001% to 5.8%, or 0.01% to 3.4%. When it is within the above range, the characteristics of the large-area magnetic part may be more stably maintained even if impact or distortion occurs repeatedly.

second magnetic part

Type of second magnetic part

The wireless charging device according to an embodiment of the present invention includes a second magnetic part having a different permeability from the first magnetic part, specifically, higher than the magnetic permeability of the first magnetic part.

The second magnetic part may include a ferritic magnetic material (ferritic magnetic part), and specifically, may include an oxide-based magnetic material, a metal-based magnetic material, or a composite material thereof.

According to the embodiment of the present invention, by using a material having a strong magnetic focusing force as the second magnetic portion, the disadvantage of the first magnetic portion, which may cause a decrease in charging efficiency due to a weak magnetic focusing force (inductance), can be compensated. have.

If only the first magnetic part is used without the second magnetic part, there may be effects such as impact resistance and weight reduction, but the magnetic focusing force (inductance) may be weak, and thus charging efficiency may be deteriorated. On the other hand, although the second magnetic part has a strong magnetic focusing force, it is difficult to process a plate enlargement, and there may be restrictions in manufacturing and processing in the form of a thick film for automobiles. Therefore, by using the second magnetic part having a strong magnetic focusing force together with the first magnetic part having high impact resistance and a weight reduction effect, the performance of the wireless charging device can be efficiently improved.

The oxide-based magnetic material may be a ferrite-based 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, and Ni). 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, and 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 air at a temperature of 800°C to 1100°C for 1 hour to 3 hours, and then adding subcomponents, and thus a binder such as polyvinyl alcohol (PVA) After mixing the resin in an appropriate amount 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. Then, 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 part or a Ni-Fe alloy magnetic part, and more specifically, sendust (sendust) or permalloy (permalloy).

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

The nanocrystalline magnetic material is manufactured by, for example, a Fe-based alloy by a rapid cooling and solidification method (RSP) by melt spinning, in a temperature range of 300 ℃ to 700 ℃ to obtain a desired magnetic permeability for 30 minutes to 2 hours without a magnetic field It can be manufactured by performing heat treatment.

If the heat treatment temperature is less than 300 ℃, nanocrystals are not sufficiently formed, so the desired magnetic permeability is not obtained, and the heat treatment time may take a long time. In addition, when the heat treatment temperature is low, the treatment time is long, and on the contrary, when the heat treatment temperature is high, the treatment time is preferably shortened.

In addition, the nanocrystalline magnetic material may be crushed by a pressure roll or the like at the end of the manufacturing process to form a plurality of cracks in the thin film sheet, so that it may be manufactured to include a plurality of nanocrystalline fine pieces.

The second magnetic part may be made of a magnetic material different from that of the first magnetic part. As a specific example, the first magnetic part includes a polymer-type magnetic part (eg, polymer-type magnetic block (PMB)) including a magnetic powder and a binder resin, and the second magnetic part includes a ferritic magnetic material, a nanocrystalline magnetic material, or a combination thereof. For example, the first magnetic part includes a Fe-Si-Al-based alloy magnetic part, and the second magnetic part includes Mn-Zn-based ferrite, Fe-Si-Al-based nanocrystalline magnetic powder, Fe-Si-Cr-based It may include at least one selected from the group consisting of a magnetic nanocrystalline powder, and a Fe-Si-B-Cu-Nb-based nanocrystalline magnetic powder. The combination of the first magnetic part and the second magnetic part is advantageous in that the second magnetic part has a high magnetic permeability at 79 kHz to 90 kHz, specifically 85 kHz, compared to the first magnetic part.

Structural features of the second magnetic part

The second magnetic part may be located at a center of the magnetic part.

By disposing the second magnetic part having a higher magnetic permeability than the first magnetic part in the central part of the magnetic part, the magnetic flux focused during wireless charging may be dispersed in the direction of the central part having a relatively smaller magnetic flux distribution. Accordingly, by lowering the magnetic flux density in the portion corresponding to the coil portion and increasing the magnetic flux density in the center where there is no coil portion, the magnetic flux and heat distribution are evenly distributed, thereby effectively improving heat reduction characteristics and wireless charging efficiency during wireless charging. .

The second magnetic part may have an entire surface or a circumferential surface of the second magnetic part surrounded by the first magnetic part.

Specifically, with reference to FIGS. 3A, 3C and 3D , the second magnetic part may have a circumferential surface of the second magnetic part surrounded by the first magnetic part.

Also, referring to FIG. 3B , the second magnetic part may have an entire surface surrounded by the first magnetic part.

The second magnetic part may have a sheet shape or a block shape.

The second magnetic part may have the same thickness as the first magnetic part. In addition, the second magnetic portion may have a different thickness from that of the first magnetic portion.

For example, the thickness of the second magnetic part may be 0.5 mm or more, 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.

Also, the thickness of the second magnetic part may be 10 mm or less, 7 mm or less, or 5 mm or less.

The thickness of the second magnetic part 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.

A maximum cross-sectional area in a horizontal direction of the second magnetic part may be 10% to 40% of a total cross-sectional area of the magnetic part. The horizontal maximum cross-sectional area of the second magnetic part is, for example, 10% to 38%, for example, 10% to 35%, for example, 10% to 34%, for example, 10% of the total cross-sectional area of the magnetic part % to 33%, such as 10% to 31%, such as 10% to 30%, such as 10% to 25%, or such as 10% to 20%.

An area of the second magnetic part may be 50 cm ² or more, 70 cm ² or more, or 100 cm ² or more. Also, the area of the second magnetic material may be 4,000 cm ² or less.

The second magnetic part may have a smaller area than the first magnetic part. In this case, the charging efficiency of the second magnetic part can be effectively improved even with a small area.

Magnetic properties of the second magnetic part

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

For example, the magnetic permeability in the frequency band of 79 kHz to 90 kHz of the second magnetic part may vary depending on the material, and may be broadly greater than 500 to 150,000, for example, may have a magnetic permeability of 1,000 to 20,000. In addition, the magnetic permeability of the second magnetic part may be 500 to 3,500, 1,000 to 5,000, more than 5,000 to 20,000, more than 10,000 to 100,000, or 8,000 to 150,000 depending on a specific material.

In addition, the investment loss in the frequency band of 79 kHz to 90 kHz of the second magnetic part 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 part is a ferritic material, the magnetic permeability in a frequency band of 79 kHz to 90 kHz, such as a frequency band of 85 kHz, may be 1,000 to 5,000, more than 1,000 to less than 5,000, or 2,000 to 4,000, and , the investment loss may be 0 to 1,000, 0 to 500, 0 to 100, or 0 to 50.

As another example, when the second magnetic part is a nanocrystalline magnetic material, the magnetic permeability in a frequency band of 79 kHz to 90 kHz, such as 85 kHz, is 5,000 or more, 5,000 or more to 150,000, 5,000 or more to 120,000, or more than 5,000 to 10,000, and may have a permeability of greater than 10,000 to 150,000. In addition, the investment loss may be 100 to 50,000, or 1,000 to 10,000.

According to the embodiment, the second magnetic part has a higher magnetic permeability at a frequency of 85 kHz than the first magnetic part. For example, the difference in permeability at a frequency of 85 kHz between the second magnetic part and the first magnetic part may be 100 or more, 500 or more, or 1,000 or more, specifically 100 to 10,000, 100 to 5,000, 500 to 4,500, or 1,000 to 4,500.

Specifically, the first magnetic portion has a magnetic permeability of 5 to 500, or 5 to 300 at a frequency of 85 kHz, and the second magnetic portion is greater than 500 to 150,000, 1,000 to 20,000, 1,000 to 10,000, or It may have a permeability of greater than 5,000 to 20,000.

In addition, the first magnetic unit may have an investment loss of 0 to 50 at 85 kHz, and the second magnetic unit may have an investment loss of 0 to 500 at 85 kHz.

During wireless charging, the magnetic flux density is higher as it approaches the coil part, but when the magnetic part is around the coil part, the magnetic flux is concentrated in the magnetic part. do. Accordingly, when the second magnetic portion having a higher magnetic permeability than the first magnetic portion is properly disposed, the magnetic flux can be effectively distributed.

shield part

The wireless charging device 10 according to the embodiment may further include a shield unit 400 that serves to increase the wireless charging efficiency through electromagnetic wave shielding.

The shield part is disposed on one surface of the coil.

The shield part includes a metal plate, and the material thereof may be aluminum, and other metal or alloy materials having electromagnetic wave shielding ability may be used.

The thickness of the shield portion 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.

spacer part

The wireless charging device according to the embodiment may further include a spacer unit for securing a space between the shield unit and the magnetic unit.

Specifically, referring back to FIGS. 3A and 3C , the magnetic part, specifically, the first magnetic part 300 and/or the second magnetic part 500 is disposed to be spaced apart from the shield part 400 by a predetermined distance. can be In addition, an empty space or a spacer part 700 may be further included between the first magnetic part 300 and/or the second magnetic part 500 , and the shield part 400 . The material and structure of the spacer part may adopt a material and structure of a typical housing used in a wireless charging device.

housing

The wireless charging device 10 according to the embodiment may further include a housing 600 accommodating the coil unit 200 , the first magnetic unit 300 , and the second magnetic unit 500 .

In addition, the housing 600 is configured such that components such as the coil unit 200, the shield unit 400, the first magnetic unit 300 and the second magnetic unit 500 are properly arranged and assembled. do. The shape (structure) of the housing may be arbitrarily set according to the components included therein or according to the environment. The material and structure of the housing may adopt the material and structure of a typical housing used in a wireless charging device.

support

The wireless charging device 10 according to the embodiment may further include a support part 100 for supporting the coil part 200 . The material and structure of the support part may adopt a material and structure of a conventional support part used in a wireless charging device. The support part may have a flat plate structure or a structure in which a groove is dug along a coil shape to fix the coil part.

On the other hand, the wireless charging device of the present invention can efficiently reduce heat generated when the coil unit receives wireless power from the outside when performing high-power wireless charging of 3 kW to 22 kW, 4 kW to 20 kW, or 5 kW to 18 kW, and charging Since efficiency can be improved, it can be usefully used for high-power wireless charging.

In particular, the wireless charging device can further improve charging efficiency and heat reduction characteristics by applying a three-dimensional structure to the magnetic part.

The charging efficiency of the wireless charging device according to an embodiment of the present invention may be 85% or more, 88% or more, 89% or more, 90% or more, or 91% or more.

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

[transportation]

9 is a moving means to which a wireless charging device is applied, specifically, an electric vehicle, and may be wirelessly charged in a parking area equipped with a wireless charging system for an electric vehicle by providing a wireless charging device at the lower part.

Referring to FIG. 9 , the electric vehicle 1 according to an embodiment includes the wireless charging device according to the embodiment as a receiver 720 .

The wireless charging device may serve as a receiver of wireless charging of the electric vehicle 1 and receive power from the transmitter 730 of wireless charging.

As such, the moving means includes a wireless charging device, and the wireless charging device includes a coil unit; and a magnetic part disposed on the coil part, wherein the magnetic part includes a first magnetic part and a second magnetic part, and the second magnetic part is located in the center of the magnetic part, and the entire surface or the circumferential surface of the second magnetic part is It is surrounded by the first magnetic part, and the magnetic permeability of the second magnetic part is higher than that of the first magnetic part.

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

The moving means 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 moving means may further include a signal transmitter for transmitting information about the charging to the transmitter of the wireless charging system. The information about such charging may be charging efficiency such as charging speed, charging state, and the like.

Hereinafter, specific embodiments of the present invention are presented. However, the examples described below are only for specifically illustrating or explaining the present invention, and the present invention is not limited thereto.

Example

Manufacture of wireless charging device

The wireless charging devices of Examples 1 and 2, and Comparative Examples 1 to 3 below may be provided with reference to FIG. 5 . However, in FIG. 5 , some components are exaggerated, omitted, or schematically illustrated, and the size of each component does not fully reflect the actual size.

Example 1

Step 1: Preparation of the first magnetic part (PMB magnetic part) (three-dimensional structure)

10 wt% of polyamide resin (product name: L1724k, manufacturer Daicel-Evonik) as a binder resin, 85 wt% of sandust (product name: C1F-02A, manufacturer Crystallite Technology) as a filler, and 5 wt% of phosphoric acid and silane as additives to prepare pellets in an extruder under the conditions of a temperature of about 170 to 200 ℃ and 120 to 150 rpm. The pellets were injected in an injection machine at a temperature of about 250° C. to obtain a first magnetic part 300 (thickness of 5 mm) having a three-dimensional structure.

Step 2: Fabrication of a hybrid magnetic part

By inserting a ferritic magnetic material (PC-95 ferrite magnetic sheet of TDK, second magnetic part) (thickness 5 mm) 500 into the first magnetic part 300 prepared in step 1, and fixing it by thermocompression bonding, the A hybrid magnetic part having a structure in which the circumferential surface of the second magnetic part 500 is surrounded by the first magnetic part 300 was obtained.

Step 3: Manufacturing of a wireless charging device

A wireless charging device including a coil unit 200 including a conductive wire, the hybrid magnetic units 300 and 500 and a shield unit 400 using the hybrid magnetic unit of step 2 (FIG. 5(a)) ) was obtained.

Example 2

A first magnetic part 300 having a three-dimensional structure was manufactured in the same manner as in Step 1 of Example 1, but the first magnetic part and a second magnetic part inserted into the first magnetic part (ferritic magnetic material (TDK)) Company's PC-95 ferrite magnetic sheet) was placed in contact with the shield part 400, and the thickness of the first magnetic part and the second magnetic part was changed to 5 mm and 3 mm, respectively, as in Example 1 In the same manner, a wireless charging device (FIG. 5(b)) including a coil unit 200 including a conductive wire, the hybrid magnetic units 300 and 500, and a shield unit 400 was obtained.

Comparative Example 1

Using only the first magnetic part (thickness 5 mm) obtained in Step 1 of Example 1 as the magnetic part, the coil part 200 including the conductive wire, the first magnetic part 300 and the shield part 400 were formed. A wireless charging device (FIG. 5 (c)) was obtained.

Comparative Example 2

Without using the first magnetic part obtained in step 1 of Example 1, using only a nanocrystalline magnetic material (FINEMET FT3, second magnetic part, manufactured by Hitachi) (thickness 5 mm), a coil part 200 including a conductive wire , a wireless charging device (FIG. 5 (d)) including the second magnetic unit 500 and the shield unit 400 was obtained.

Comparative Example 3

The position of the ferritic magnetic body (PC-95 ferrite magnetic sheet manufactured by TDK, the second magnetic part) is determined by the circumferential surface of the first magnetic part 300 by the second magnetic part 500 as shown in FIG. 5(e). Wireless charging including a coil unit 200 including a conductive wire, the hybrid magnetic units 300 and 500 and the shield unit 400 in the same manner as in Example 1, except that it is disposed to be surrounded A device (FIG. 5(e)) was obtained.

test example

(1) Measurement of exothermic temperature

The wireless charging device obtained in the above Examples and Comparative Examples was placed in the housing to obtain a wireless charging device.

In the SAE J2954 WPT2 Z2 class Standard TEST charging efficiency measurement condition for the wireless charging device obtained in the Examples and Comparative Examples, when wireless power having a frequency of 85 kHz and an output of 6.6 kW is transmitted to the coil unit for 30 minutes, magnetic The negative surface temperature was measured.

Specifically, the surface temperature of the magnetic part is measured based on the center (maximum heating temperature) of the position corresponding to the coil part among the lower surfaces of the magnetic part of Examples and Comparative Examples using T/GUARD 405-SYSTEM of Qualitrol Corporation. (Exothermic temperature (T), see FIG. 5).

(2) Charging Efficiency Measurement

Charging efficiency was measured by SAE J2954 WPT2 Z2 Class standard TEST method. Specifically, SAE J2954 WPT2 Z2 Class standard TEST standard coil part and frame are applied and magnetic part, spacer, and aluminum plate are stacked to manufacture receiving pad (35 cm X 35 cm) and transmitting pad (75 cm X 60 cm). Therefore, the charging efficiency was evaluated under the same conditions with an output power of 6.6 kW at a frequency of 85 kHz.

The measurement results are shown in Table 1 and FIGS. 6 and 7 below.

As shown in Table 1 and FIGS. 6 and 7, two types of hybrid magnetic parts having different permeability are used, and in this case, a second magnetic part having a higher magnetic permeability than the first magnetic part is disposed in the center of the magnetic part. The wireless charging device of 1 and 2 is a hybrid type including the first magnetic part and the second magnetic part, as well as the wireless charging device of Comparative Example 1 using only the first magnetic part and the wireless charging device of Comparative Example 2 using only the second magnetic part, but the present application It was confirmed that, compared to the wireless charging device of Comparative Example 3 having different inventions and structures, it was possible to effectively disperse magnetic flux and heat to significantly improve heat reduction characteristics and wireless charging efficiency.

Specifically, when the wireless power having a frequency of 85 kHz and an output of 6.6 kW is transmitted to the coil unit for 30 minutes, in the case of the wireless charging devices of Examples 1 and 2, the heating temperature of the magnetic unit is the temperature of Comparative Examples 1 to 3 Compared to the exothermic temperature of the magnetic part, it was lowered to about 12 °C to 80 °C. In addition, when wireless power is transmitted for 30 minutes, the charging efficiency of the wireless charging device of Examples 1 and 2 is about 89.5% and about 89.9%, respectively, whereas the charging efficiency of the wireless charging device of Comparative Example 1 is 87%, The charging efficiency of the wireless charging device of Comparative Example 2 was 79%, the charging efficiency of the wireless charging device of Comparative Example 3 was 87%, and it was confirmed that the charging efficiency of the wireless charging device of Examples 1 and 2 was significantly improved. have.

In particular, the wireless charging device of Example 1 is the heating temperature (T ₁₅ ) of the upper surface of the magnetic part when the wireless power is transmitted for 15 minutes, the heating temperature of the lower surface of the magnetic part when the wireless power is transmitted for 30 minutes ( T ₃₀ ) increased by about 26.4° C., while the wireless charging device of Comparative Example 1 was about 31.6° C. from T ₁₅ to T ₃₀ , and it was found that the exothermic temperature rapidly increased.

On the other hand, like the wireless charging device of Embodiment 2, when the first magnetic part and the second magnetic part contact the shield part, the charging efficiency is higher than the wireless charging device of Embodiment 1 in which the magnetic parts do not contact the shield part. It can be seen that improved

On the other hand, like the wireless charging device of Comparative Example 3, although a hybrid structure including a first magnetic part and a second magnetic part, when the circumferential surface of the first magnetic part is disposed to be surrounded by the second magnetic part, the hybrid type is It can be seen that the heat reduction characteristics and wireless charging efficiency were improved compared to the wireless charging devices of Comparative Examples 1 and 2, but the heat reduction characteristics and the wireless charging efficiency were lowered compared to the wireless charging devices of Examples 1 and 2.

Therefore, it was confirmed that the charging efficiency and heat reduction characteristics of the wireless charging device can be improved in an efficient way according to the embodiment of the present invention.

1: means of transportation (electric vehicle), 10: wireless charging device
100: support part 200: coil part
300: first magnetic part 400: shield part
500: second magnetic part 510: upper surface
520: bottom 530: circumferential surface
600: housing 700: spacer part
701: raw material composition 702: injection molding machine
703 : mold
720: receiver 730: transmitter
T: exothermic temperature (measurement position)

Claims (8)

coil unit;
and a magnetic part disposed on the coil part;
The magnetic part includes a first magnetic part and a second magnetic part,
The second magnetic part is located in the center of the magnetic part,
The entire surface or circumferential surface of the second magnetic part is surrounded by the first magnetic part,
The magnetic permeability of the second magnetic part is higher than the magnetic permeability of the first magnetic part,
When the coil unit receives wireless power from the outside, the heating value of the second magnetic part is higher than that of the first magnetic part, the wireless charging device.
The method of claim 1,
The first magnetic part includes a magnetic powder and a binder resin,
The second magnetic part includes a ferritic magnetic material, a nanocrystalline magnetic material, or a combination thereof, a wireless charging device.
3. The method of claim 2,
The first magnetic part has a magnetic permeability of 5 to 500 at 85 kHz,
The second magnetic portion has a magnetic permeability of greater than 500 to 150,000 at 85 kHz,
wireless charging device.
The method of claim 1,
The horizontal maximum cross-sectional area of the second magnetic part is 10% to 40% of the total cross-sectional area of the magnetic part, the wireless charging device.
The method of claim 1,
T ₁₅ is the heating temperature of the upper surface of the magnetic unit when the magnetic unit transmits wireless power having a frequency of 85 kHz and an output of 6.6 kW to the coil unit for 15 minutes,
When the heating temperature of the lower surface of the magnetic part when the wireless power is transmitted for 30 minutes is T ₃₀ ,
The T ₁₅ to the T ₃₀ to 30 ℃ or less increased further, the wireless charging device.
6. The method of claim 5,
The T ₁₅ is 40 ℃ to 65 ℃,
The T ₃₀ is 50 ℃ to 95 ℃, the wireless charging device.
The method of claim 1,
Further comprising a shield portion disposed on the magnetic portion,
At least a portion of the magnetic portion is in contact with the shield portion, a wireless charging device.
A mobile means comprising the wireless charging device according to claim 1 .

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