KR102765996B1 - Wireless charging pad, wireless charging device, and electric vehicle comprising same - Google Patents

Abstract

A wireless charging pad according to an embodiment of the present invention can improve charging efficiency and heat dissipation characteristics by applying a three-dimensional structure to a magnetic material. Therefore, the wireless charging pad and a wireless charging device employing the structure thereof can 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 COMPRISING SAME}

The embodiments relate to a wireless charging pad, a wireless charging device, and an electric vehicle including the same. More specifically, the embodiments relate to a wireless charging pad, a wireless charging device, and an electric vehicle including the same, wherein charging efficiency is improved by applying a heat dissipation structure.

Today, the information and communication field is developing at a very fast pace, and various technologies that comprehensively combine electricity, electronics, communications, and semiconductors are continuously being developed. In addition, as the trend toward mobile electronic devices increases, research on wireless communication and wireless power transmission technologies is also actively being conducted in the communications field. In particular, research on methods for wirelessly transmitting power to electronic devices is actively being conducted.

The above wireless power transmission is a method of wirelessly transmitting power through space using inductive coupling, capacitive coupling, or an electromagnetic resonance structure such as an antenna without physical contact between a transmitter that supplies power and a receiver that receives power. The above wireless power transmission is suitable for portable communication devices and electric vehicles that require large-capacity batteries, and since the contact points are not exposed, there is almost no risk of current leakage, and the charging failure phenomenon of the wired method can be prevented.

Meanwhile, as interest in electric vehicles has been rapidly increasing, interest in building charging infrastructure has also been increasing. Various charging methods have already appeared, including charging electric vehicles using home chargers, battery replacement, rapid charging devices, and wireless charging devices, and new charging business models have also begun to appear (see Korean Patent Publication No. 2011-0042403). In addition, in Europe, test-operated electric vehicles and charging stations have begun to be noticed, and in Japan, automobile manufacturers and power companies are taking the lead in pilot operation of electric vehicles and charging stations.

Korean Patent Publication No. 2011-0042403

In a conventional wireless charging pad used in electric vehicles, etc., with reference to FIG. 3, a magnetic material (300') is placed adjacent to a coil (200') to improve wireless charging efficiency, and a shield part (400') for electromagnetic shielding is placed at a certain distance from the magnetic material (300').

The wireless charging pad generates heat due to the resistance of the coil and the magnetic loss of the magnetic material during the wireless charging operation. In particular, the magnetic material inside the wireless charging pad generates heat near the coil where the electromagnetic wave energy density is high, and the generated heat changes the magnetic properties of the magnetic material, causing an impedance mismatch between the transmitting pad and the receiving pad, which reduces the charging efficiency and causes heat generation to worsen again. However, since these wireless charging pads are installed on the bottom of electric vehicles, they adopt a sealed structure for dustproofing, waterproofing, and shock absorption, making it difficult to implement a heat dissipation structure.

Accordingly, as a result of research conducted by the inventors of the present invention, it was discovered that charging efficiency and heat dissipation characteristics can be improved by applying a three-dimensional structure to the magnetic material used in the wireless charging pad.

Therefore, the task of the embodiment is to provide a wireless charging pad, a wireless charging device, and an electric vehicle including the same with improved charging efficiency and heat dissipation characteristics by applying a magnetic material having a three-dimensional structure.

According to one embodiment, a wireless charging pad is provided, comprising: a coil including a conductive wire; a shield portion disposed on the coil; and a first magnetic material disposed between the coil and the shield portion, wherein when a region corresponding to the coil in the first magnetic material is defined as a first region and another region is defined as a second region, the first region of the first magnetic material has a thicker thickness than the second region.

According to another embodiment, a wireless charging device is provided, comprising: 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 disposed between the coil and the shield portion, wherein when a region corresponding to the coil in the first magnetic material is defined as a first region and another region is defined as a second region, the first region of the first magnetic material has a thicker thickness than the second region.

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

According to the above implementation example, by applying a three-dimensional structure to the magnetic material used in the wireless charging pad, the charging efficiency and heat dissipation characteristics can be improved.

Specifically, according to an embodiment, by increasing the thickness of the magnetic material at the rear of the coil where electromagnetic energy is concentrated during wireless charging and decreasing the thickness of the magnetic material at the center where the electromagnetic energy density is relatively low, the wireless charging efficiency can be increased while reducing the heat generated from the magnetic material.

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

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

In the description of the implementation examples below, when it is described that one component is formed on or below another component, it includes both that one component is formed directly on or below the other component, or indirectly through the interposition of another component.

In addition, the upper/lower criteria for each component are explained based on the drawing. The size of each component in the drawing may be exaggerated for explanation and may differ from the size actually applied.

In this specification, the term "including" a component does not exclude other components, unless otherwise specifically stated, but rather means that other components may be included.

In addition, it should be understood that all numerical ranges indicating characteristic values, dimensions, etc. of the components described in this specification are qualified by the term “about” in all cases unless otherwise specified.

In this specification, singular expressions should be interpreted to include the singular or plural as interpreted by the context, unless otherwise specified.

[Wireless charging pad]

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

Referring to FIG. 1, a wireless charging pad (10) according to one embodiment includes a coil (200) including a conductive wire; a shield portion (400) disposed on the coil (200); and a first magnetic material (300) disposed between the coil (200) and the shield portion (400). When a region corresponding to the coil in the first magnetic material (300) is defined as a first region (310) and other regions are defined as second regions (320), the first region (310) of the first magnetic material has a thicker thickness than the second region (320).

Below, each component of the wireless charging pad is described in detail.

Support plate

The wireless charging pad (10) may further include a support plate (100) that supports the coil (200). The material and structure of the support plate may adopt the material and structure of a typical support plate used in a wireless charging pad. The support plate may have a flat structure or a structure in which a groove is dug along the coil shape so as to fix the coil.

coil

The above coil includes a conductive wire.

The conductive wire comprises a conductive material. For example, the conductive wire may comprise a conductive metal. Specifically, the conductive wire may comprise 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 outer sheath. For example, the insulating outer sheath may include an insulating polymer resin. Specifically, the insulating outer sheath 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 planar 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 thereto.

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

Additionally, the inner diameter of the flat coil may be 0.5 cm to 30 cm, 1 cm to 20 cm, or 2 cm to 15 cm.

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

Additionally, the spacing between the conductive wires within the flat coil shape may be 0.1 cm to 1 cm, 0.1 cm to 0.5 cm, or 0.5 cm to 1 cm.

Within the above desirable plane coil dimensions and specification ranges, it can be suitable for fields requiring large-capacity power transmission, such as electric vehicles.

Shield department

The above shield portion is placed on the coil.

The above shield portion suppresses electromagnetic interference (EMI) that may occur when electromagnetic waves leak to the outside through electromagnetic shielding.

The shield portion may be positioned at a predetermined distance from the coil. For example, the distance between the shield portion and the coil may be 10 mm or more or 15 mm or more, and specifically, may be 10 mm to 30 mm, or 10 mm to 20 mm.

The material of the above shield part may be, for example, metal, and accordingly, 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 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 portion may be 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more.

First magnetic material

The above first magnetic material is placed between the coil and the shield portion.

The first magnetic material may be arranged at a predetermined distance from the coil. For example, the 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.

Additionally, the first magnetic material may be positioned at a predetermined distance from the shield portion. For example, the 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.

Alternatively, a part of the first magnetic material may contact the shield portion. For example, as shown in FIG. 2a, the first region (310) of the first magnetic material (300) may contact the shield portion (400). Specifically, at least a part of the first region of the first magnetic material may contact the shield portion. Alternatively, the entire first region of the first magnetic material may contact the shield portion. In this case, the second region of the first magnetic material may not contact the shield portion.

Three-dimensional structure of the first magnetic material

According to the above embodiment, by applying a three-dimensional structure to the first magnetic material, the charging efficiency and heat dissipation characteristics can be improved. That is, when the region corresponding to the coil in the first magnetic material is defined as the first region, and the other region is defined as the second region, the first region of the first magnetic material has a thicker thickness than the second region. At this time, the first region and the second region in the first magnetic material can be formed integrally with each other.

By increasing the thickness of the magnetic material at the rear of the coil where electromagnetic energy is concentrated during wireless charging and reducing the thickness of the magnetic material at the center where the electromagnetic energy density is relatively low, the electromagnetic waves concentrated around the coil are effectively focused, thereby not only improving charging efficiency, but also making it possible to firmly maintain the distance between the coil and the shield without a separate spacer, thereby reducing material costs and process costs associated with the use of spacers, etc.

In the above first magnetic material, the first region may have a thickness that is 1.5 times or more thicker than the second region. At the above thickness ratio, electromagnetic waves concentrated around the coil can be more effectively focused, thereby improving charging efficiency and also advantageous in heat generation and weight reduction. Specifically, the thickness ratio of the first region/second region in the first magnetic material 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 also 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 also 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.

In addition, the thickness of the second region of the first magnetic material may be 0. That is, as shown in FIG. 2b, the first magnetic material (300) may have a hollow shape in the second region (320). In this case, the first magnetic material can effectively improve the 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, an area of 200 cm ² or more, 400 cm ² or more, or 600 cm ² or more. In addition, 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 composed of a combination of a plurality of unit magnetic materials, and at this time, the area of the unit magnetic material may be 60 cm ² or more, 90 cm ² , or 95 cm ² to 900 cm ² .

Alternatively, the first magnetic material may have a hollow shape in the second region, in which case it may have an area corresponding to the area of the first region, i.e., the coil.

The above first magnetic material may be a magnetic block manufactured by a method such as molding through a mold. For example, the above 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 binder resin and injecting them into a mold by injection molding or the like.

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

Specifically, the laminate of the magnetic sheets may have one or more additional magnetic sheets laminated only on the second region of the first magnetic material.

At this time, the thickness of the individual magnetic sheets may be 80 ㎛ or more, or 85 ㎛ to 150 ㎛. These magnetic sheets may be manufactured by a conventional sheet-making process, such as mixing magnetic powder and binder resin to make a slurry, forming it into a sheet shape, and curing it.

magnetic powder

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

Accordingly, the first magnetic material can have a small number of defects overall over a large area and be less susceptible to damage by impact since the magnetic powders are bound to each other by the binder resin.

The above magnetic powder may be an oxide-based magnetic powder such as a ferrite (Ni-Zn-based, Mg-Zn-based, Mn-Zn-based ferrite, etc.); a metal-based magnetic powder such as a permalloy, a sentust, a nanocrystalline magnetic material; or a mixed powder thereof. More specifically, the magnetic powder may be a sentust particle having an Fe-Si-Al alloy composition.

As an example, the magnetic powder may have a composition represented by the following chemical formula 1.

[Chemical Formula 1]

Fe _1-abc Si _a X _b Y _c

In the above formula, 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.

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

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

For example, the first magnetic material can contain the magnetic powder in an amount of 50 wt% to 99 wt%, 70 wt% to 95 wt%, 70 wt% to 90 wt%, 75 wt% to 90 wt%, 75 wt% to 95 wt%, 80 wt% to 95 wt%, or 80 wt% to 90 wt%.

Binder resin

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

As a resin that can be cured in this way to exhibit adhesiveness, a resin can be used that includes at least one functional group or site capable of being cured by heat, such as a glycidyl group, an isocyanate group, a hydroxyl group, a carboxyl group, or an amide group; or a resin that includes at least one functional group or site capable of being cured by activation energy, such as an epoxide group, a cyclic ether group, a sulfide group, an acetal group, or a lactone group. Such a functional group or site can be, for example, an isocyanate group, a hydroxyl group, or a carboxyl group.

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

As an example, the binder resin may include a polyurethane-based resin, an isocyanate-based curing agent, and an epoxy-based resin.

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, the first magnetic material may include, based on its weight, 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 as the binder resin.

Magnetic properties of the first magnetic material

The above first magnetic material can have a certain level of magnetic properties near the standard frequency for wireless charging of electric vehicles.

The standard frequency for wireless charging of the above 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 band distinct from the frequency applied to mobile electronic devices such as mobile phones.

The permeability of the first magnetic material in the frequency band of 79 kHz to 90 kHz may vary depending on the material, but may be 5 or more, for example, 5 to 150,000, and may be 5 to 300, 500 to 3,500, or 10,000 to 150,000 depending on the specific material. In addition, the permeability loss of the first magnetic material in the frequency band of 79 kHz to 90 kHz may vary depending on the material, but may be 0 or more, for example, 0 to 50,000, and may be 0 to 1,000, 1 to 100, 100 to 1,000, or 5,000 to 50,000 depending on the specific material.

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

Characteristics of the first magnetic material

The above first magnetic material can be elongated at a certain ratio. For example, the elongation of the first magnetic material can be 0.5% or more. The above elongation characteristic is difficult to obtain in a ceramic 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 can 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 when the content of the polymer resin increases to improve the elongation, the characteristics of the magnetic material, such as inductance, may deteriorate, and therefore, it is preferable that the elongation is 10% or less.

The above first magnetic material has a small rate of change in characteristics before and after impact, and is far superior to general sintered ferrite magnetic sheets.

In this specification, the change rate (%) of characteristics before and after impact can be calculated by the following equation.

Characteristic change rate (%) = |Characteristic value before impact - Characteristic value after impact| / Characteristic value before impact × 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%. Within the above range, the inductance change rate before and after the impact is relatively small, so that the stability of the magnetic material can be further improved.

In addition, the first magnetic material may have a quality factor (Q factor) change rate of 0% to 5%, 0.001% to 4%, or 0.01% to 2.5% before and after an impact applied by free falling from a height of 1 m. Within the above range, the change in characteristics before and after the impact is small, so that 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. Within the above range, the resistance value can be well maintained below a certain level even when repeatedly applied in an environment where actual impact and vibration are applied.

In addition, the first magnetic material may have a change in charging efficiency before and after an impact applied by free falling from a height of 1 m of 0% to 6.8%, 0.001% to 5.8%, or 0.01% to 3.4%. Within the above range, the large-area magnetic material can maintain its characteristics more stably even when impact or distortion occurs repeatedly.

Second magnetic material

The wireless charging pad according to the above embodiment can improve the charging efficiency and heat dissipation characteristics by including an additional second magnetic material in addition to the first magnetic material. Specifically, as shown in FIG. 2c, the wireless charging pad can additionally include a second magnetic material (500) disposed on the first region (310) of the first magnetic material (300).

The second magnetic material may be disposed on one surface of the shield portion facing the first magnetic material. That is, the second magnetic material may be disposed between the shield portion and the first magnetic material.

For example, the second magnetic material is attached to one surface of the shield portion, so that heat generated from the second magnetic material can be effectively discharged through the shield portion. Specifically, the second magnetic material is attached to one surface of the shield portion with a heat-conductive adhesive, so that the heat dissipation effect can be further enhanced.

The above thermally conductive adhesive may include a thermally conductive material such as a metal-based, carbon-based, or ceramic-based adhesive, and may be, for example, an adhesive resin in which thermally conductive particles are dispersed.

The second magnetic material may be arranged at a predetermined distance from the first magnetic material. For example, the distance between the first magnetic material and the second magnetic material may be 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.

The second magnetic material may have a sheet shape or a ribbon shape. 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 a large area, similar to that of 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. Additionally, 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 on the first region of the first magnetic material, the second magnetic material may have an area corresponding to the area of the first region. In addition, accordingly, the second magnetic material may be disposed corresponding to the region where the coil exists, and may have an area corresponding to the area of the coil. In this case, the second magnetic material may effectively improve charging efficiency and heat dissipation characteristics even with a small area.

Properties of the second magnetic material

The above second magnetic material may have magnetic properties in a specific range near the standard frequency for wireless charging of electric vehicles.

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

As a specific example, when the second magnetic material is a nanocrystalline magnetic material, the permeability may be 500 to 3,000, or 10,000 to 150,000, and the investment loss may be 100 to 1,000, or 8,000 to 50,000 in a frequency band of 79 kHz to 90 kHz.

Preferably, the second magnetic material has a relatively high magnetic permeability compared to the first magnetic material, thereby improving the charging efficiency of the wireless charging pad. For example, the second magnetic material may have a high magnetic permeability at 79 kHz to 90 kHz compared to the first magnetic material. Specifically, the difference in the magnetic 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, 1,000 or more, or 10,000 or more, and specifically may be 100 to 200,000, 500 to 50,000, or 1,000 to 10,000.

During wireless charging, the magnetic flux density is higher the closer it is to the coil, but if there is a magnetic material around the coil, the magnetic flux is concentrated on the magnetic material, and if there is more than one magnetic material, the magnetic flux density increases in the order of the magnetic permeability of the magnetic material. Therefore, if the second magnetic material with a higher permeability than the first magnetic material is appropriately arranged, the magnetic flux can be effectively distributed.

In addition, the horizontal thermal conductivity of the second magnetic material may be 1 W/mK or more, for example, 1 W/mK to 30 W/mK, or 10 W/mK to 20 W/mK. In addition, the vertical thermal conductivity of the second magnetic material may be 0.1 W/mK or more, for example, 0.1 W/mK to 2 W/mK, or 0.5 W/mK to 1.5 W/mK. Specifically, the second magnetic material may have horizontal thermal conductivity of 1 W/mK to 30 W/mK and vertical thermal conductivity of 0.1 W/mK to 2 W/mK.

Therefore, heat generated during wireless charging due to investment loss in the second magnetic material can be discharged through the shield portion adjacent to the second magnetic material.

Composition of the second magnetic material

The above second magnetic material may include a metal-based magnetic material.

The second magnetic material may include a nanocrystalline magnetic material.

When a nanocrystalline magnetic material is applied as the second magnetic material, the inductance (Ls) of the coil decreases as the distance from the coil increases, but the resistance (Rs) decreases further, thereby increasing the quality factor (Q factor: Ls/Rs) of the coil, thereby improving charging efficiency and reducing heat generation.

For example, the second magnetic material may be an Fe-based nanocrystalline magnetic material, and specifically, may be an Fe-Si-Al-based nanocrystalline magnetic material, an Fe-Si-Cr-based nanocrystalline magnetic material, or an Fe-Si-B-Cu-Nb-based nanocrystalline magnetic material.

More specifically, the second magnetic material may be a Fe-Si-B-Cu-Nb nanocrystalline magnetic material, in which case, Fe may be 70 to 85 element%, the sum of Si and B may be 10 to 29 element%, and the sum of Cu and Nb may be 1 to 5 element% (here, the element% means the percentage of the number of a specific element with respect to the total number of elements forming the magnetic material). In the above composition range, the Fe-Si-B-Cu-Nb alloy can be easily formed into a nanocrystalline magnetic material by heat treatment.

Method for manufacturing a second magnetic material

The above nanocrystalline magnetic material can be manufactured by, for example, manufacturing an Fe-based alloy by a rapid solidification method (RSP) using melt spinning, and performing a non-magnetic field heat treatment at a temperature range of 300°C to 700°C for 30 minutes to 2 hours so as to obtain a desired permeability.

If the heat treatment temperature is less than 300℃, nanocrystals are not sufficiently formed, so the desired investment rate cannot be obtained and the heat treatment time may be long. If it exceeds 700℃, the investment rate may be significantly reduced due to overheat treatment. In addition, if the heat treatment temperature is low, the treatment time is long, and conversely, if the heat treatment temperature is high, the treatment time is preferably shortened.

Nanocrystalline magnetic materials are difficult to manufacture with a thick thickness in the manufacturing process, and can be formed as thin film sheets having a thickness of, for example, 15 ㎛ to 35 ㎛. Therefore, a plurality of such thin film sheets can be laminated to form a magnetic material. At this time, an adhesive layer, such as an adhesive tape, can be inserted between the thin film sheets. In addition, the magnetic material can be manufactured to include a plurality of nanocrystalline micro-pieces by forming a plurality of cracks in the thin film sheets by crushing them with a pressure roll or the like at the end of the manufacturing process.

[Wireless charging device]

FIGS. 2A to 2C are cross-sectional views of a wireless charging device according to an embodiment. Referring to FIGS. 2A to 2C, a 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 portion (400) disposed on the coil (200); and a first magnetic material (300) disposed between the coil (200) and the shield portion (400). When a region corresponding to the coil (200) in the first magnetic material (300) is defined as a first region (310) and other regions are defined as second regions (320), the first region (310) of the first magnetic material has a thicker thickness than the second region (320).

The above housing enables components such as the coil, shield, and magnetic material to be appropriately 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 above embodiment may further include a support plate that supports the coil. The configuration and characteristics of the support plate, coil, shield, and magnetic material of the wireless charging device are as described above for the wireless charging pad. Therefore, the wireless charging device substantially includes the configuration and characteristics of the wireless charging pad.

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

The wireless charging device described above can improve charging efficiency and heat dissipation characteristics by applying a three-dimensional structure to a magnetic material. Therefore, the wireless charging device described above can be usefully used in electric vehicles that require large-capacity power transmission between a transmitter and a receiver.

[Electric car]

Figure 4 illustrates an electric vehicle equipped with a wireless charging device.

The above electric vehicle can be wirelessly charged in a parking area equipped with a wireless charging system for electric vehicles.

Referring to FIG. 4, an electric vehicle (1) according to one embodiment includes a wireless charging device according to the embodiment as a receiver (21).

The above wireless charging device acts as a wireless charging receiver (21) of an electric vehicle (1) and can receive power from a wireless charging transmitter (22).

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 disposed between the coil and the shield portion, wherein when a region corresponding to the coil in the first magnetic material is defined as a first region and another region is defined as a second region, the first region of the first magnetic material has a thicker thickness than the second region.

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

The above wireless charging device may be installed on the lower part of the vehicle.

The electric vehicle may further include a battery that receives power from the wireless charging device. The wireless charging device may wirelessly receive power and transmit it to the battery, and the battery may supply power to the drivetrain 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 a transmitter of a wireless charging system for the electric vehicle. The information about charging may be charging efficiency, charging status, etc., such as charging speed.

1: Electric car, 10, 10': Wireless charging pad,
11: Wireless charging device,
21: Receiver, 22: Transmitter,
100, 100': Support plate, 200, 200': Coil,
300: 1st magnetic material, 300': Magnetic material,
310: Area 1, 320: Area 2,
400, 400': Shield, 500: Second magnetic material,
600: Housing.

Claims (11)

A coil comprising a conductive wire;
A shield portion arranged on the above coil; and
Including a first magnetic material arranged between the coil and the shield portion,
When defining the region corresponding to the coil in the first magnetic material as the first region and defining the other region as the second region, the first region of the first magnetic material has a thickness that is 1.5 times or more thicker than the second region, and the thickness of the second region is 0.1 mm or more,
A wireless charging pad further comprising a second magnetic material disposed on the first region of the first magnetic material, wherein the second magnetic material has a magnetic permeability that is 100 or higher at 79 kHz to 90 kHz compared to the first magnetic material.
delete In paragraph 1,
A wireless charging pad, wherein the first region of the first magnetic material has a thickness of 5 mm to 11 mm, and the second region has a thickness of 0.1 mm to 5 mm.
In paragraph 1,
A wireless charging pad, wherein the first magnetic material comprises a binder resin and magnetic powder dispersed within the binder resin.
In paragraph 1,
A wireless charging pad, wherein at least a portion of the first region of the first magnetic material is in contact with the shield portion.
In paragraph 1,
A wireless charging pad, wherein the first magnetic material has a hollow shape in the second region.
In paragraph 1,
A wireless charging pad, wherein the first magnetic material is formed into a three-dimensional structure through a mold.
delete In paragraph 1,
A wireless charging pad, wherein the second magnetic material includes a nanocrystalline magnetic material.
housing;
A coil disposed within the housing and including a conductive wire;
A shield portion arranged on the above coil; and
Including a first magnetic material arranged between the coil and the shield portion,
When defining the region corresponding to the coil in the first magnetic material as the first region and defining the other region as the second region, the first region of the first magnetic material has a thickness that is 1.5 times or more thicker than the second region, and the thickness of the second region is 0.1 mm or more,
A wireless charging device further comprising a second magnetic material disposed on the first region of the first magnetic material, wherein the second magnetic material has a magnetic permeability that is 100 or higher at 79 kHz to 90 kHz compared to the first magnetic material.
An electric vehicle comprising a wireless charging device according to claim 10.

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