Wireless charging device and mobile tool including the same

Abstract

The wireless charging device according to an embodiment includes two magnetic components with different magnetic properties, wherein the two magnetic components can be properly arranged to effectively disperse the heat generated during wireless charging through the distribution of magnetic flux and improve durability to resist external impact and deformation. Therefore, the wireless charging device can be effectively used in mobile tools such as electric vehicles that require a large amount of power to be transmitted between a transmitter and a receiver.

Description

Technical Field

[0001] The present invention relates to a wireless charging device and a mobile tool including the same. More specifically, the present invention relates to a wireless charging device and a mobile tool including the same that improves charging efficiency through a heat dissipation structure. Background Art

[0002] In recent years, the information and communication fields are developing rapidly, and various technologies that comprehensively combine electricity, electronics, communications, and semiconductors are also developing continuously. In addition, as the mobility of electronic devices increases, research on wireless communication and wireless power transmission technology is also being actively carried out in the communication field. In particular, research on methods for wirelessly transmitting electric energy to electronic devices is being actively carried out.

[0003] Wireless power transmission refers to the wireless transmission of power in space using inductive coupling, capacitive coupling, or electromagnetic field resonant structures such as antennas without physical contact between the transmitter that provides power and the receiver that receives power. Wireless power transmission is suitable for portable communication devices, electric vehicles, etc. that require large-capacity batteries. Since the contacts are not exposed, the risk of short circuit is very small, which can prevent charging failure in wired methods.

[0004] At the same time, due to the rapid growth of interest in electric vehicles in recent years, the focus on the construction of charging infrastructure is also increasing. For example, a variety of charging methods for charging electric vehicles using home chargers, battery replacement, fast charging devices, and wireless charging devices have emerged. A new charging business model has also begun to emerge (see Korean Publication Patent, Publication No. 2011-0042403). In addition, electric vehicles and charging stations under testing are also beginning to stand out in Europe. In Japan, electric vehicles and charging stations are being piloted, led by automakers and power companies.

[0005] In a conventional wireless charging device for an electric vehicle, a magnetic material is disposed adjacent to the coil to improve wireless charging efficiency, and a metal plate for shielding is disposed at a preset interval from the magnetic material.

[0006] During the operation of wireless charging, the wireless charging device generates heat due to the coil resistance and the magnetic loss of the magnetic material. In particular, in the wireless charging device, the part of the magnetic material close to the coil with high electromagnetic wave energy density will generate heat. The heat generated will change the magnetic properties of the magnetic material and cause impedance mismatch between the transmitter and the receiver, thereby reducing the charging efficiency. As a result, the heating is aggravated. However, since such wireless charging devices are installed in the lower part of the electric vehicle, they use a sealing structure for dustproof, waterproof and shock absorption. Therefore, it is difficult to set a heat dissipation structure.

[0007] [Prior art literature]

[0008] (Patent Document 1) Korean Patent Publication No. 2011-0042403 Summary of the invention

[0009] Technical issues

[0010] In conventional wireless charging devices, a sintered ferrite sheet as a magnetic material is usually inserted between the coil and the metal plate, especially on the side close to the coil. However, the sintered ferrite sheet has a high specific gravity, and when the distance between the coil and the metal plate is close (for example, 10 mm), the efficiency drops sharply.

[0011] Therefore, a separate structure such as a partition is required to maintain the distance between the coil and the metal plate and stably fix the sintered ferrite sheet. As a result, there is a problem of increased assembly process cost. In addition, the coil and the sintered ferrite sheet generate heat during charging. In particular, the heat generated by the sintered ferrite sheet is difficult to transfer and dissipate into the air or the partition with low thermal conductivity. As a result, the magnetic properties of the sintered ferrite with increased temperature deteriorate, causing the inductance value of the coil to change, thereby reducing the charging efficiency and causing more severe heat generation.

[0012] To solve this problem, if enough magnetic material is used to fill the gap between the coil and the metal plate, the heat dissipation can be improved. However, the high specific gravity of the magnetic material increases the overall weight, which may lead to the problem of reducing the weight of the vehicle and significantly increasing the manufacturing cost. In addition, a method of using heat dissipation material to fill the gap between the magnetic material and the metal plate is currently being considered. In this case, due to the conductivity or insulation of the heat dissipation material, the charging efficiency will be reduced and the manufacturing cost will increase. If the heat dissipation material is only filled in part of the gap between the magnetic material and the metal plate, the heat dissipation performance will be insufficient.

[0013] Therefore, from the research results obtained by the inventors, it has been found that when a hybrid magnetic material is introduced into a wireless charging device, the charging efficiency, heat dissipation and durability can be improved. The above-mentioned hybrid magnetic material combination has two or more magnetic units with different magnetic permeabilities at the frequency used for wireless charging of electric vehicles.

[0014] Therefore, the problem solved by the present embodiment is to provide a wireless charging device that improves charging efficiency, heat dissipation and durability by introducing two or more magnetic materials with different magnetic properties, and a mobile tool including the wireless charging device.

[0015] Solutions to the problem

[0016] As described in one embodiment, a wireless charging device is provided, which includes a coil unit; a shielding unit arranged on the coil unit; and a magnetic unit including a first magnetic unit and a second magnetic unit and arranged between the coil unit and the shielding unit, wherein the magnetic permeability of the second magnetic unit is higher than the magnetic permeability of the first magnetic unit at 85kHz.

[0017] As described in another embodiment, a mobile tool is provided, which includes a wireless charging device, wherein the wireless charging device includes a coil unit; a shielding unit arranged above the coil unit; and a magnetic unit including a first magnetic unit and a second magnetic unit and arranged between the coil unit and the shielding unit, wherein the magnetic permeability of the second magnetic unit is higher than the magnetic permeability of the first magnetic unit at 85kHz.

[0018] Advantageous Effects of the Invention

[0019] Since the wireless charging device according to the embodiment includes two or more magnetic units having different magnetic permeabilities at a frequency used for wireless charging of electric vehicles, the charging efficiency, heat dissipation and durability can be improved.

[0020] Specifically, the two magnetic units have different magnetic properties, such as magnetic permeability. When there is one or more magnetic units, the magnetic flux density increases with the increase in the size of the magnetic permeability. Therefore, by combining the magnetic flux gathered during wireless charging, it can be distributed in the desired direction. In addition, during wireless charging, the heat generated is proportional to the amount of magnetic flux gathered on the magnetic unit and the loss of magnetic permeability. Therefore, when the two magnetic units are arranged at appropriate intervals, the heat can be effectively transferred to the shielding unit and dissipated to the outside, and damage that may be caused by external impact or deformation during vehicle driving can be suppressed.

[0021] Therefore, the wireless charging device can be effectively used in mobile tools such as electric vehicles that require large-capacity power transmission between a transmitter and a receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1a , 2a 3a are respectively an exploded perspective view, a perspective view and a cross-sectional view of a wireless charging device according to an embodiment.

[0023] 1B , 2 b and 3 b are respectively an exploded perspective view, a perspective view and a cross-sectional view of a wireless charging device according to another embodiment.

[0024] Figure 3c and 3d They are respectively cross-sectional views of a wireless charging device according to yet another embodiment.

[0025] Figure 4FIG. 4 is an exploded perspective view of a wireless charging device according to yet another embodiment.

[0026] Figures 5a to 5c They are respectively cross-sectional views of a wireless charging device according to yet another embodiment.

[0027] Figure 6 , 7 8a are respectively an exploded perspective view, a perspective view and a cross-sectional view of a wireless charging device according to yet another embodiment.

[0028] Figures 8b to 9b They are respectively cross-sectional views of a wireless charging device according to yet another embodiment.

[0029] Fig.10 A process of forming a magnetic unit by a mold is illustrated.

[0030] Fig.11 An electric vehicle is shown with a wireless charging device as a receiver.

[0031] <Description of Reference Numerals>

[0032] 1: Mobile tools (electric vehicles)

[0033] 2: Injection molding machine 3: Mold

[0034] 10: Wireless charging device

[0035] 21: Receiver 22: Transmitter

[0036] 100: Support unit 200: Coil unit

[0037] 300: First magnetic unit 301: Raw material composition

[0038] 310: outside 320: center

[0039] 400: shielding unit 500: second magnetic unit

[0040] 600: Shell

[0041] 700: cooling unit 800: tray

[0042] P1: Lower side of the first magnetic unit

[0043] P2: Upper side of the second magnetic unit DETAILED DESCRIPTION

[0044] In the following description of the embodiments, when mentioning that an element is formed "on" or "under" another element, it not only means that one element is directly formed "on" or "under" another element, but also means that one element is indirectly formed on or under another element with other elements (singular or plural other elements) interposed therebetween.

[0045] In addition, the terms above or below related to each element may refer to the drawings. For convenience of explanation, the sizes of individual elements in the drawings are exaggerated and depicted, and they may be different from the actual sizes.

[0046] Throughout the specification, when it is mentioned that a component “includes” an element, it should be understood that it can include other elements rather than excluding the possibility of including other elements, unless explicitly stated otherwise.

[0047] Furthermore, unless otherwise indicated, all numbers expressing physical properties, dimensions, and the like of elements used herein are to be understood as being modified by the term "about."

[0048] In this specification, unless otherwise specified, a singular expression should be understood as including a singular or plural expression, which is interpreted according to the context.

[0049] Wireless charging device

[0050] The wireless charging device as described in the embodiment includes a coil unit, a shielding unit arranged on the coil unit, and a magnetic unit including a first magnetic unit and a second magnetic unit and arranged between the coil unit and the shielding unit, wherein the magnetic permeability of the second magnetic unit is higher than the magnetic permeability of the first magnetic unit at 85kHz.

[0051] Since the wireless charging device according to the embodiment includes two magnetic units with different magnetic permeabilities at a frequency used for wireless charging of electric vehicles, the charging efficiency, heat dissipation characteristics and durability can be improved.

[0052] At the same time, if two or more magnetic units are combined to be used as a hybrid magnetic unit, but are simply stacked and placed without special consideration, the magnetic flux will be improperly distributed during wireless charging, making it impossible to effectively transfer the generated heat to the outside, and it may be easily damaged by external impact during vehicle driving.

[0053] To solve this problem, a second magnetic unit in which heat generated during wireless charging is greater than that of the first magnetic unit may be disposed closer to the shielding unit. For example, when the second magnetic unit is disposed above the first magnetic unit and the coil unit receives wireless power from the outside, more heat may be generated in the second magnetic unit than in the first magnetic unit.

[0054] See also Figure 1a and 1b The wireless charging device (100) as described in the embodiment includes a coil unit (200); a first magnetic unit (300) arranged on the coil unit (200); a second magnetic unit (500) arranged on the first magnetic unit (300); and a shielding unit (400) arranged on the second magnetic unit (500), wherein when the coil unit (200) receives wireless power from the outside, the heat generated in the second magnetic unit (500) can be greater than that in the first magnetic unit (300).

[0055] As described in the above embodiments, two or more magnetic units that generate different amounts of heat during wireless charging are used and arranged in consideration of their characteristics, so that the heat generated during wireless charging can be reduced and the charging efficiency can be further improved. Specifically, since the second magnetic unit that generates more heat in the magnetic unit than the first magnetic unit during wireless charging is disposed closer to the shielding unit, the magnetic flux density and heat dissipation can be effectively distributed to increase the wireless charging efficiency, and the heat generated by the second magnetic unit can be dissipated to the outside through the shielding unit to effectively improve the heat dissipation characteristics.

[0056] In addition, when the magnetic unit used in the wireless charging device uses a three-dimensional structure and the heat dissipation unit is appropriately used in combination with an additional magnetic unit having different magnetic properties, the charging efficiency and heat dissipation properties can be improved. For example, the wireless charging device also includes a heat dissipation unit disposed between the shielding unit and the magnetic unit, wherein the first magnetic unit may include an outer portion corresponding to a portion where the coil unit is disposed; and a central portion surrounded by the outer portion, and the thickness of the outer portion may be greater than the thickness of the central portion.

[0057] See also Figure 4 The wireless charging device (10) as described in the embodiment includes a coil unit (200), the coil unit (200) includes a wire; a shielding unit (400) arranged on the coil unit (200); a magnetic unit arranged between the coil unit (200) and the shielding unit (400) and including a first magnetic unit (300) and a second magnetic unit (500); and a heat dissipation unit (700) arranged between the shielding unit (400) and the second magnetic unit (500), wherein the first magnetic unit (300) may include an outer portion (310) corresponding to a portion where the coil unit (200) is arranged and a central portion (320) surrounded by the outer portion (310), the thickness of the outer portion (310) may be greater than the thickness of the central portion (320), and the magnetic permeability of the second magnetic unit (500) may be higher than the magnetic permeability of the first magnetic unit (300) at 85kHz.

[0058] As described in the above embodiments, when the magnetic unit used in the wireless charging device uses a three-dimensional structure and two magnetic units are used, the charging efficiency and heat dissipation characteristics can be improved at the same time. Specifically, as described in the above embodiments, as the thickness of the magnetic unit near the coil unit where the electromagnetic energy is concentrated during wireless charging increases, and the thickness of the central magnetic unit where the electromagnetic energy density is relatively low decreases, the efficiency of wireless charging can be improved and the heat generation of the magnetic unit can be reduced. In addition, since a second magnetic unit with a higher magnetic permeability than the first magnetic unit is used, the magnetic flux density and heat dissipation can be effectively distributed to increase the wireless charging efficiency, and the heat generated by the second magnetic unit can be dissipated to the outside through the shielding unit to improve the heat dissipation characteristics. In addition, the heat dissipation unit can prevent the magnetic unit from being damaged due to external impact, and at the same time make it easy for the heat of the magnetic unit to be transferred to the shielding unit.

[0059] In addition, as the distance from the shielding unit is adjusted according to the characteristics of the first magnetic unit and the second magnetic unit, the heat generated during wireless charging can be effectively dispersed by distributing the magnetic flux, and the durability can be improved to resist external impact or deformation. Specifically, the second magnetic unit can be disposed on the first magnetic unit (for example, between the first magnetic unit and the shielding unit), and the second magnetic unit can be thermally connected to the shielding layer.

[0060] See also Figure 6 , 7 8a to 9b, the wireless charging device (10) as described in the embodiment includes a coil unit (200); a first magnetic unit (300) arranged on the coil unit (200); a second magnetic unit (500) arranged on the first magnetic unit (300) and having a higher magnetic permeability than the first magnetic unit (300) at 85kHz; and a shielding unit (400) arranged on the coil unit (400), wherein the second magnetic unit (500) can be thermally connected to the shielding layer (400).

[0061] As described in the above embodiment, while using two magnetic units, the magnetic unit with higher magnetic permeability is set adjacent to the shielding unit, so that it can effectively disperse the heat generated during wireless charging by distributing the magnetic flux. In addition, by adjusting the materials of the two magnetic units, the durability can be improved to resist external impact or deformation. Specifically, the two magnetic units have different magnetic properties, such as magnetic permeability. When there is one or more magnetic units, the magnetic flux density increases with the size of the magnetic permeability. Therefore, by combining the magnetic flux gathered during wireless charging, it can be distributed in the desired direction. In addition, during wireless charging, the heat generated is proportional to the amount of magnetic flux gathered on the magnetic unit and the loss of magnetic permeability. Therefore, when the two magnetic units are arranged at appropriate intervals, the heat can be effectively transferred to the shielding unit and dissipated to the outside, and damage caused by external impact or deformation that may be suffered during vehicle driving can be prevented.

[0062] Each constituent element of the wireless charging device will be described in detail below.

[0063] Coil unit

[0064] The coil unit may include a conductive wire.

[0065] The wire includes a conductive material. For example, the wire may include a conductive metal. Specifically, the wire may include at least one metal selected from copper, nickel, gold, silver, zinc and tin.

[0066] In addition, the wire may have an insulating sheath. For example, the insulating sheath may include an insulating polymer resin. Specifically, the insulating sheath may include polyvinyl chloride (PVC) resin, polyethylene (PE) resin, Teflon resin, silicone resin, polyurethane resin, etc.

[0067] The diameter of the wire may be, for example, 1 mm to 10 mm, 1 mm to 5 mm, or 1 mm to 3 mm.

[0068] The 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 circular, elliptical, polygonal, or polygonal with rounded corners, but is not particularly limited thereto.

[0069] The outer diameter of the planar coil may be 5 cm to 10 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 outer diameter of the planar coil may be 10 cm to 50 cm.

[0070] Furthermore, 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.

[0071] The number of turns of the planar coil may be 5 to 50 times, 10 to 30 times, 5 to 30 times, 15 to 50 times, or 20 to 50 times. As a specific example, the planar coil may be formed by winding the wire 10 to 30 times.

[0072] Furthermore, 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.

[0073] Within the preferred size and specification range of the planar coil, it can be applied to fields requiring large-capacity power transmission, such as electric vehicles.

[0074] The coil unit may be disposed to be spaced apart from the first magnetic unit at a preset interval. For example, the distance between the coil unit and the first magnetic unit may be 0.2 mm or more, 0.5 mm or more, 0.2 mm to 0.3 mm, or 0.5 mm to 1.2 mm.

[0075] Shielding unit

[0076] The shielding unit is disposed above the coil and the magnetic unit.

[0077] The shielding unit suppresses electromagnetic interference (EMI) that may be generated by electromagnetic waves leaking to the outside through electromagnetic shielding.

[0078] The shielding unit may be arranged to be spaced apart from the coil unit at a preset interval. For example, the distance between the shielding unit and the coil unit may be 10 mm or more or 15 mm or more, specifically, 10 mm to 30 mm or 10 mm to 20 mm.

[0079] In addition, the shielding unit may be arranged to be spaced apart from the first magnetic unit at a preset interval. For example, the distance between the shielding unit and the first magnetic unit may be 3 mm or more, 5 mm or more, 3 mm to 10 mm, or 4 mm to 7 mm.

[0080] The material of the shielding unit may be, for example, metal. Therefore, the shielding unit may be a metal plate, but is not particularly limited thereto. As a specific example, the material of the shielding unit may be aluminum. Other metal or alloy materials having electromagnetic wave shielding capability may also be used.

[0081] The thickness of the shielding unit 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 shielding unit may be 200 cm 2 or above, 400cm 2 or above or 600cm 2 or above.

[0082] Magnetic unit

[0083] The wireless charging device as described in the embodiment includes a first magnetic unit and a second magnetic unit having a higher magnetic permeability than the first magnetic unit.

[0084] Since a material with a strong magnetic focusing force is used as the above-mentioned second magnetic unit, the disadvantage of the first magnetic unit's reduced charging efficiency due to its weak magnetic focusing force can be compensated. If the first magnetic unit is used alone without the second magnetic unit, it may have the effect of impact resistance and weight reduction, but the magnetic focusing force is weak, which will reduce the charging efficiency. At the same time, although the second magnetic unit has a strong magnetic focusing force, it may be difficult to process it into a large flat plate, and it may be restricted in manufacturing and processing it into a thick layer form for automobiles. Therefore, when the second magnetic unit with a strong magnetic focusing force is used together with the first magnetic unit with high impact resistance and weight reduction effects, the performance of the wireless charging device can be effectively improved.

[0085] For example, the wireless charging device may include a first magnetic unit disposed on the coil unit and a second magnetic unit disposed on the first magnetic unit and having a higher magnetic permeability than the first magnetic unit. In addition, the first magnetic unit and the second magnetic unit may be disposed between the coil unit and the shielding unit.

[0086] As described in detail in the example, the first magnetic unit may include a binder resin and magnetic powder dispersed in the binder resin, and the magnetic unit may include a ferrite-based magnetic material.

[0087] The first magnetic unit and the second magnetic unit may have magnetic properties within a certain range near a standard frequency for wireless charging of electric vehicles. The standard frequency for wireless charging of electric vehicles may be lower than 100kHz, for example, 79kHz to 90kHz, specifically, 81kHz to 90kHz, more specifically, about 85kHz. This is a frequency band different from the frequency used in mobile electronic devices such as mobile phones.

[0088] In particular, the components of the first magnetic unit and the second magnetic unit determine that they have differences in magnetic properties such as permeability and permeability loss. Therefore, the two magnetic units are combined so that it is possible to effectively disperse the heat generated during wireless charging through the distribution of magnetic flux.

[0089] For example, the magnetic permeability of the second magnetic unit may be higher than the magnetic permeability of the first magnetic unit at 85 kHz. In addition, the magnetic permeability loss of the second magnetic unit may be higher than the magnetic permeability loss of the first magnetic unit at 85 kHz.

[0090] Specifically, at 85 kHz, the difference in magnetic permeability between the second magnetic unit and the first magnetic unit may be 100 or more, 500 or more, or 1000 or more, specifically, 100 to 5000, 500 to 4000, or 1000 to 3000. In addition, at 85 kHz, the difference in magnetic permeability loss between the second magnetic unit and the first magnetic unit may be 10 or more, 50 or more, or 100 or more, specifically, 10 to 300, 50 to 250, or 100 to 200.

[0091] Specifically, the first magnetic unit may have a magnetic permeability of 5 to 300 at a frequency of 85 kHz, and the second magnetic unit may have a magnetic permeability of 1000 to 5000 at a frequency of 85 kHz. More specifically, the first magnetic unit may have a magnetic permeability of 5 to 300 and a magnetic permeability loss of 0 to 30 at a frequency of 85 kHz, and the second magnetic unit may have a magnetic permeability of 1000 to 5000 and a magnetic permeability loss of 0 to 300 at a frequency of 85 kHz.

[0092] Although the magnetic flux density increases as it approaches the coil unit during wireless charging, if the magnetic unit surrounds the coil unit, the magnetic flux will be concentrated on the magnetic unit. If two or more magnetic units are used, the magnetic flux density will increase as the magnetic permeability of the magnetic unit increases. Therefore, if the second magnetic unit with a higher magnetic permeability than the first magnetic unit is properly arranged, the magnetic flux can be effectively distributed.

[0093] In addition, since the heat generated during wireless charging is proportional to the amount of magnetic flux gathered on the magnetic unit and the loss of magnetic permeability, there is also a difference in the heat generated by the two magnetic units during wireless charging. For example, during wireless charging such as transmitting or receiving electric energy, specifically, when the coil unit receives wireless power from the outside, the heat generated by the second magnetic unit may be greater than the heat generated by the first magnetic unit.

[0094] Since the two magnetic units described above have different magnetic properties and heat generation, the magnetic flux density gathered during wireless charging can be distributed in a desired direction by using the tendency of the magnetic flux density to increase with the increase in the magnitude of the magnetic permeability, wherein the magnitude of the magnetic permeability depends on the method of arranging and combining the magnetic units. In addition, by using the tendency of the heat generation to increase in proportion to the amount of magnetic flux and the magnitude of the magnetic permeability loss, the heat can be effectively dissipated to the outside.

[0095] See also Figure 1a and 1b, the first magnetic unit (300) is arranged closer to the coil unit (200) than the second magnetic unit (500), and the second magnetic unit (500) is arranged closer to the shielding unit (400) than the first magnetic unit (300). In this case, the second magnetic unit can be thermally connected to the shielding unit. Therefore, a large amount of heat generated in the second magnetic unit can be easily released to the outside through the shielding unit.

[0096] In addition, since the amount (volume) of each magnetic unit is adjusted based on the magnetic properties and physical properties of the two magnetic units, the impact resistance can be improved and the manufacturing cost can be reduced without compromising the charging efficiency. For example, the volume of the first magnetic unit can be larger than the volume of the second magnetic unit.

[0097] The composition and characteristics of each magnetic unit will be described in detail below.

[0098] The first magnetic unit

[0099] The first magnetic unit may include a binder resin and a magnetic powder dispersed in the binder resin.

[0100] For example, the first magnetic unit may be a polymer magnetic material or a polymer-type magnetic block (PMB).

[0101] When the magnetic powders are bonded to each other by the binder resin, the first magnetic unit may have fewer defects over a large area and may be less damaged by impact.

[0102] The magnetic powder may be an oxide-based magnetic powder, a metal-based magnetic powder, and 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, more specifically, a Sendust powder or a Permalloy powder.

[0103] As an example, the composition of the magnetic powder may be as shown in Formula 1 below.

[0104] [Formula 1]

[0105] Fe 1-a-b-c Si a X b Y c

[0106] 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.

[0107] In addition, the magnetic powder can be a nanocrystalline magnetic powder. For example, it can be a Fe-based nanocrystalline magnetic powder. Specifically, it can be a Fe-Si-Al-based nanocrystalline magnetic powder, a Fe-Si-Cr-based nanocrystalline magnetic powder or a Fe-Si-B-Cu-Nb-based nanocrystalline magnetic powder.

[0108] The average particle size of the magnetic powder may range from about 3 nm to 1 mm, from about 1 μm to 300 μm, from about 1 μm to 50 μm, or from about 1 μm to 10 μm.

[0109] The first magnetic unit may include the magnetic powder in an amount of 10% or more by weight, 50% or more by weight, 70% or more by weight, or 85% or more by weight.

[0110] For example, the first magnetic unit may include magnetic powder in an amount of 10% to 99% of its weight, 10% to 95% of its weight, 50% to 95% of its weight, 50% to 92% of its weight, 70% to 95% of its weight, 80% to 95% of its weight, or 80% to 90% of its weight.

[0111] Examples of the binder resin include polyimide resin, polyamide resin, polycarbonate resin, acrylonitrile-butadiene-styrene (ABS) resin, polypropylene resin, polyethylene resin, polystyrene resin, polyphenylene sulfide (PPS) resin, polyether etherketone (PEEK) resin, silicone resin, acrylic resin, polyurethane resin, polyester resin, isocyanate resin and epoxy resin, but are not limited thereto.

[0112] For example, the binder resin may be a curable resin. Specifically, the binder resin may be a photocurable resin and / or a thermosetting resin. In particular, it may be a resin that exhibits adhesiveness when cured. More specifically, the resin that may be used as the binder resin may include at least one functional group or part that is capable of thermal curing, 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 part that can be cured by active energy, such as an epoxy group, a cyclic ether group, a thioether group, an acetal group, or a lactone group. Such a functional group or part may be, for example, an isocyanate group (-NCO), a hydroxyl group (-OH), or a carboxyl group (-COOH).

[0113] The first magnetic unit may include the resin in an amount of 5% to 40% by weight, 5% to 20% by weight, 5% to 15% by weight, or 7% to 15% by weight.

[0114] In addition, based on its weight, the first magnetic unit may include 6% to 12% of its weight of polyurethane resin, 0.5% to 2% of its weight of isocyanate curing agent, and 0.3% to 1.5% of its weight of epoxy resin as a binder resin.

[0115] Characteristics of the first magnetic unit

[0116] The first magnetic unit may have magnetic properties within a certain range around a standard frequency for wireless charging of electric vehicles.

[0117] The magnetic permeability of the first magnetic unit at a frequency of 85kHz may vary depending on the material. Depending on the specific material, it may range from 5 to 150,000, and may specifically be 5 to 300, 500 to 3,500, or 10,000 to 150,000. In addition, the magnetic permeability loss of the first magnetic unit at a frequency of 85kHz may vary depending on the material. Depending on the specific material, it may range from 0 to 50,000, and may specifically be 0 to 1,000, 1 to 100, 100 to 1,000, or 5,000 to 50,000.

[0118] As a specific example, when the first magnetic unit is a polymer magnetic unit including magnetic powder and a binder resin, at a frequency of 85 kHz, its magnetic permeability can be 5 to 500, 5 to 130, 15 to 80 or 10 to 50, and its magnetic permeability loss can be 0 to 50, 0 to 20, 0 to 15 or 0 to 5.

[0119] In addition, the first magnetic unit can be elongated at a certain ratio. For example, the elongation of the first magnetic unit can be 0.5% or more. Ceramic-based magnetic materials that do not apply polymers are difficult to have elongation properties. Even if a large-area magnetic unit is deformed by impact, it can reduce damage. Specifically, the elongation of the first magnetic unit can be 0.5% or more, 1% or more, or 2.5% or more. The upper limit of the elongation is not particularly limited. However, if the elongation is increased by increasing the content of the polymer resin, the inductance and other properties of the magnetic unit may deteriorate. Therefore, the elongation is preferably 10% or less.

[0120] The first magnetic unit has a small change rate of characteristics before and after the impact, and its change rate of characteristics is significantly better than that of the traditional ferrite magnetic sheet. In this specification, the change rate (%) of certain characteristics before and after the impact can be calculated by the following formula.

[0121] Characteristic change rate (%) = |Characteristic value before impact - characteristic value after impact| / characteristic value before impact × 100

[0122] For example, when the first magnetic unit is freely dropped from a height of 1m, the change rate of its inductance before and after the impact may be less than 5% or 3% or less. More specifically, the change rate of the inductance may be 0% to 3%, 0.001% to 2%, or 0.01% to 1.5%. Within the above range, since the change rate of the inductance before and after the impact is relatively small, the stability of the magnetic unit can be further improved.

[0123] In addition, when the first magnetic unit is freely dropped from a height of 1m, the change rate of its Q value (Ls / Rs) before and after the impact can be 0% to 5%, 0.001% to 4%, or 0.01% to 2.5%. Within the above range, since the change rate of the characteristics before and after the impact is small, the stability and impact resistance of the magnetic unit can be further improved.

[0124] In addition, when the first magnetic unit is freely dropped from a height of 1m, the change rate of its resistance before and after the impact can be 0% to 2.8%, 0.001% to 1.8%, or 0.1% to 1.0%. Within the above range, even if repeatedly used in an environment of real impact and vibration, the resistance value can be well maintained below a certain level.

[0125] In addition, when the first magnetic unit falls freely from a height of 1m, the change rate of its charging efficiency before and after the impact can be 0% to 6.8%, 0.001% to 5.8%, or 0.01% to 3.4%. Within the above range, even if the large-area magnetic unit is repeatedly impacted and deformed, it can maintain its characteristics more stably.

[0126] Structural characteristics of the first magnetic unit

[0127] Since the first magnetic unit has a three-dimensional structure, the charging efficiency and heat dissipation characteristics can be further improved. Figure 3b and 3d , the first magnetic unit (300) may include an outer portion (310) corresponding to the setting position of the coil unit (200); and a central portion (320) surrounded by the outer portion (310), wherein the thickness of the outer portion (310) may be greater than the thickness of the central portion (320). That is, the outer portion of the first magnetic unit may be placed corresponding to the portion of the coil unit with a high-density wire. The central portion of the first magnetic unit may be placed corresponding to the portion of the coil unit with a low-density wire. In this case, the outer portion and the central portion of the first magnetic unit may be formed integrally with each other.

[0128] As described above, as the thickness of the magnetic unit near the coil where the electromagnetic energy is concentrated during wireless charging increases, and as the thickness of the central magnetic unit with a relatively low electromagnetic energy density due to being not close to the coil decreases, it can not only effectively gather the electromagnetic waves concentrated around the coil to improve the charging efficiency, but also firmly maintain the distance between the coil and the shielding unit without a separate partition, thereby reducing the material and process costs brought about by the use of partitions, etc.

[0129] In the first magnetic unit, the thickness of the outer part may be 1.5 times or more thicker than the thickness of the central part. Within the above thickness ratio range, the electromagnetic waves concentrated around the coil can be more effectively gathered to improve the charging efficiency, and it is also advantageous for heat generation and weight reduction. Specifically, in the first magnetic unit, the thickness ratio of the outer part and the central part 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.

[0130] The thickness of the outer portion of the first magnetic unit may be 1 mm or more, 3 mm or more, or 5 mm or more, and 30 mm or less, 20 mm or less, or 11 mm or less. In addition, the thickness of the central portion of the first magnetic unit may be 10 mm or less, 7 mm or less, or 5 mm or less, and 0 mm, 0.1 mm or more, or 1 mm or more. Specifically, the thickness of the outer portion of the first magnetic unit may be 5 mm to 11 mm, and the thickness of the central portion thereof may be 0 mm to 5 mm.

[0131] When the thickness of the central portion (320) of the first magnetic unit (300) is 0, the central portion (320) of the first magnetic unit (300) may be empty (e.g., in a circular shape). In this case, even if the area is reduced, the first magnetic unit can effectively improve the charging efficiency.

[0132] Alternatively, the first magnetic unit may have a planar structure rather than a three-dimensional structure. Figure 3a and 3c , in the first magnetic unit (300), the outer portion (310) and the central portion (320) may have the same thickness.

[0133] Composition and characteristics of the second magnetic unit

[0134] The second magnetic unit may include an oxide-based magnetic material, a metal-based magnetic material, or a composite material thereof.

[0135] For example, the oxide-based magnetic material can be a ferrite-based magnetic material. Its specific chemical formula can be expressed as MOFe2O3 (wherein M is one or more divalent metal elements, such as Mn, Zn, Cu and Ni). Considering the magnetic properties such as magnetic permeability, the ferrite-based magnetic material is preferably a sintered body. The ferrite-based magnetic material can be prepared into a sheet or block by mixing raw materials, then calcining, crushing, mixing with a binder resin, molding and sintering.

[0136] More specifically, the ferrite-based magnetic material may be Ni-Zn-based, Mg-Zn-based or Mn-Zn-based ferrite. In particular, Mn-Zn-based ferrite may exhibit high magnetic permeability, low magnetic permeability loss and high saturation magnetic flux density at a frequency of 85 kHz and a temperature range of from room temperature to 100° C. or higher.

[0137] Mn-Zn-based ferrite includes 66 mol% to 70 mol% of Fe2O3, 10 mol% to 20 mol% of ZnO, 8 mol% to 24 mol% of MnO, 0.4 mol% to 2 mol% of NiO as main components, and further includes SiO2, CaO, Nb2O5, ZrO2, SnO and the like as additional minor components. Mn-Zn-based ferrite can be prepared into a sheet or block by mixing the main components in a preset molar ratio, calcining it in air at a temperature of 800°C to 1100°C for 1 hour to 3 hours, adding the minor components thereto and grinding it, mixing it with an appropriate amount of a binder resin such as polyvinyl alcohol (PVA), press-molding it using a press machine, and sintering it at a temperature of 1200°C to 1300°C for 2 hours or more. Thereafter, if necessary, it is processed and cut into a desired size using a wire saw or a water jet.

[0138] In addition, the metal-based magnetic material may be a Fe-Si-Al alloy magnetic material or a Ni-Fe alloy magnetic material, more specifically, Sendust powder or Permalloy powder. In addition, the second magnetic unit may include a nanocrystalline magnetic material. For example, it may be a Fe-based nanocrystalline magnetic material. Specifically, it may include a Fe-Si-Al-based nanocrystalline magnetic material, a Fe-Si-Cr-based nanocrystalline magnetic material, or a Fe-Si-B-Cu-Nb-based nanocrystalline magnetic material. If a nanocrystalline magnetic material is used as the second magnetic unit, the farther the distance from the coil, the lower the resistance (Rs) even if the inductance (Ls) of the coil is reduced. Therefore, the quality factor (Q value: Ls / Rs) of the coil increases, which can improve charging efficiency and reduce heat generation.

[0139] The second magnetic unit may be formed of a magnetic material different from that of the first magnetic unit. As a specific example, the first magnetic unit may include a Fe-Si-Al-based alloy magnetic material, and the second magnetic unit may include one or more selected from Mn-Zn-based ferrites, Fe-Si-Al-based nanocrystalline magnetic materials, Fe-Si-Cr-based nanocrystalline magnetic materials, and Fe-Si-B-Cu-Nb-based nanocrystalline magnetic materials. The combination of these materials is conducive to making the magnetic permeability of the second magnetic unit higher than the magnetic permeability of the first magnetic unit at a frequency of 85kHz.

[0140] The second magnetic unit may have magnetic properties within a certain range around a standard frequency for wireless charging of electric vehicles.

[0141] For example, the magnetic permeability of the second magnetic unit at a frequency of 85kHz may vary depending on the material. Depending on the specific material, it may range from 5 to 150,000, and may specifically be 5 to 300, 500 to 3,500, or 10,000 to 150,000. In addition, the magnetic permeability loss of the second magnetic unit at a frequency of 85kHz may vary depending on the material. Depending on the specific material, it may range from 0 to 50,000, and may specifically be 0 to 1,000, 1 to 100, 100 to 1,000, or 5,000 to 50,000.

[0142] As a specific example, if the second magnetic unit is a ferrite-based magnetic material, its magnetic permeability may be 1000-20000, 1000-5000 or 2000-4000, and its magnetic permeability loss may be 0-1000, 0-100 or 0-50 at a frequency of 85 kHz.

[0143] Area and thickness of the first magnetic unit and the second magnetic unit

[0144] The first magnetic unit has a larger area. Specifically, its area can be 200cm 2 or above, 400cm 2 or above or 600cm 2 In addition, the area of ​​the first magnetic unit can be 10000cm 2 Or less. In addition, a large-area first magnetic unit can be configured by combining a plurality of unit magnetic materials. In this case, the area of ​​a single unit magnetic material can be 60 cm 2 or above, 90cm 2 or above or 95cm 2 Up to 900cm 2 .

[0145] Alternatively, the center of the first magnetic unit may be empty. In this case, the first magnetic unit may have an outer area, that is, an area corresponding to the coil unit.

[0146] The first magnetic unit may be a magnetic block prepared by a method such as mold molding. For example, the first magnetic unit may be a three-dimensional structure molded by a mold. Such a magnetic block may be obtained by mixing magnetic powder and a binder resin and injecting it into a mold by injection molding to mold into a three-dimensional structure.

[0147] Specifically, the raw material of the magnetic unit can be injected into a mold for molding by injection molding. More specifically, the raw material composition can be obtained by mixing magnetic powder and polymer resin components, and then by Fig.10 The injection molding machine (2) shown injects the raw material components (301) into the mold (3) to prepare the magnetic unit. In this case, the internal shape of the mold (3) can be designed as a three-dimensional structure, so that the three-dimensional structure of the magnetic unit can be easily realized. When using a conventional ferrite sheet as the magnetic unit, this process may be difficult to achieve.

[0148] Alternatively, the first magnetic unit may be a magnetic sheet laminate. For example, it may be a laminate of 20 or more or 50 or more magnetic sheets.

[0149] Specifically, in the magnetic sheet laminate, one or more magnetic sheets may be further laminated only on the outside of the first magnetic unit. In this case, the thickness of each magnetic sheet may be 80 μm or more or 85 μm to 150 μm. Such a magnetic sheet may be prepared by a conventional sheet forming process, for example, by mixing a magnetic powder and a binder resin to form a slurry, which is then molded into a sheet shape and cured.

[0150] The second magnetic unit may be in a sheet or block shape.

[0151] The thickness of the second magnetic unit may be 0.5 mm to 5 mm, specifically, 0.5 mm to 3 mm, 0.5 mm to 2 mm, or 1 mm to 2 mm. The thickness of the outer portion of the first magnetic unit may be greater than the thickness of the second magnetic unit. For example, the thickness of the outer portion may be 5 mm to 11 mm, and the thickness of the second magnetic unit may be 0.5 mm to 3 mm.

[0152] At the same time, the second magnetic unit can have a thickness less than that of the first magnetic unit and a higher magnetic permeability than that of the first magnetic unit at a frequency of 85kHz. In a wireless charging device designed to optimize the thickness ratio and magnetic permeability of the first magnetic unit and the second magnetic unit, the characteristics of maximizing charging efficiency and reducing heat generation can be achieved, especially at high power.

[0153] The total thickness of the first magnetic unit and the second magnetic unit may be 2.1 mm to 10 mm, 3.0 mm to 9 mm, or 4.0 mm to 8 mm. If the total thickness of the first magnetic unit and the second magnetic unit is too thin, the weight of the magnetic unit may decrease, which may limit its process or use.

[0154] The area of ​​the second magnetic unit may be the same as or different from the area of ​​the first magnetic unit.

[0155] For example, the second magnetic unit may have the same large area as the first magnetic unit. Specifically, the area of ​​the second magnetic unit may be 200 cm 2 or above, 400cm 2 or above or 600cm 2 In addition, the area of ​​the second magnetic unit can be 10000cm 2 Or less. In addition, a second magnetic unit with a large area can be configured by combining multiple unit magnetic materials. In this case, the area of ​​a single unit magnetic material can be 60cm 2 or above, 90cm 2 or above or 95cm 2 Up to 900cm 2 .

[0156] Alternatively, the second magnetic unit may have an area smaller than the first magnetic unit. For example, if the second magnetic unit is only disposed on the outside of the first magnetic unit, the second magnetic unit may have an area corresponding to the area of ​​the outside. In addition, correspondingly, the second magnetic unit may be disposed at a corresponding position of the coil unit and have an area corresponding to the area of ​​the coil unit. In this case, even if the area is small, the second magnetic unit can effectively improve the charging efficiency and heat dissipation characteristics.

[0157] The heat generated by the first magnetic unit and the second magnetic unit

[0158] The magnetic unit may form a magnetic path around the magnetic field formed by the coil unit, and is disposed between the coil unit and the shielding unit.

[0159] See also Figure 1a and 1b The wireless charging device (10) may include a hybrid magnetic unit that combines a first magnetic unit (300) and a second magnetic unit (500) having different heat dissipation amounts.

[0160] Specifically, the second magnetic unit (500) may be disposed above the first magnetic unit (300). When the coil unit (200) receives wireless power from the outside, more heat is generated in the second magnetic unit (500) than in the first magnetic unit (300).

[0161] Since the second magnetic unit (500) that generates more heat than the first magnetic unit (300) during wireless charging is arranged closer to the shielding unit (400), the magnetic flux density and heat dissipation can be effectively distributed to increase the wireless charging efficiency, and the heat generated by the second magnetic unit (500) can be dissipated to the outside through the shielding unit (400) to improve the heat dissipation characteristics.

[0162] Specifically, when the coil unit receives wireless power from the outside, the magnetic unit may have a temperature within a specific range to enhance the effect of reducing heat generation.

[0163] See also Figures 3a to 3d When the coil unit receives wireless power with a frequency of 85 kHz and an output of 6.6 kW for 10 minutes, the temperature (T1 10 ) can be higher than the temperature (T2) of the upper side (P2) of the second magnetic unit (500) (ie, the side of the second magnetic unit facing the shielding unit) 10 ) is lower by 1°C or more. If the above range is met, the charging efficiency and heat reduction characteristics can be maximized.

[0164] Specifically, when the coil unit receives wireless power for 10 minutes, the temperature (T1 10 ) can be higher than the temperature (T2 10 ) can be 1°C to 5°C lower, for example, can be 1°C to 4°C, 1°C to 3°C, or 2°C to 3°C lower.

[0165] If only one of the first magnetic unit and the second magnetic unit is used, or if the arrangement of the first magnetic unit and the second magnetic unit is changed, it is possible that T1 10 Equal to or higher than T2 10 In this case, heat generation during fast charging and high-power wireless charging increases, which may lead to safety issues such as damage to the wireless charging device and the possibility of power conversion circuit failure, thereby limiting use or reducing charging efficiency.

[0166] The surface temperature of the magnetic unit can be measured under the SAE J2954 WPT2 Z2 class standard test charging efficiency measurement conditions specified by the Society of Automotive Engineers (SAE). The above standards are based on a variety of content, such as the capacity performance of the wireless power transfer system, interoperability, vertical and horizontal spacing benchmarks for generating rated output, communication methods between transceivers, operating frequencies, electromagnetic interface (EMI) / electromagnetic compatibility (EMC), and stability. Since the above standards provide not only system performance but also transceiver specifications for each capacity band, most automakers follow the transceiver configuration and size recommended in the above standards when manufacturing transceivers.

[0167] Specifically, Figures 3a to 3d As shown, when the coil unit receives wireless power with a frequency of 85kHz and an output of 6.6kW for 10 minutes or 60 minutes, a T / GUARD 405-system manufactured by Qualitrol (company name) is used to measure the lower side (P1) of the first magnetic unit and the upper side (P2) of the second magnetic unit, respectively. Herein, the surface temperature can be measured based on the center point of the outside, which corresponds to the coil unit.

[0168] T1 10 It may be, for example, 55°C to 75°C, 57°C to 73°C, 58°C to 70°C, or 58°C to 67°C.

[0169] In addition, T2 10 It may be, for example, 56°C to 76°C, 58°C to 74°C, 59°C to 71°C, or 60°C to 70°C.

[0170] Furthermore, when the coil unit receives wireless power with a frequency of 85 kHz and an output of 6.6 kW for 60 minutes, the temperature (T1 60 ) and the temperature on the upper side of the second magnetic unit (T2 60 ) can be 100°C to 180°C respectively.

[0171] T1 60 It may be, for example, 100°C to 180°C, 120°C to 180°C, 130°C to 180°C, 130°C to 160°C, or 136°C to 150°C.

[0172] In addition, T2 60 It may be, for example, 100°C to 180°C, 120°C to 180°C, 120°C to 170°C, 125°C to 165°C, or 130°C to 160°C.

[0173] Since the first magnetic unit and the second magnetic unit each have a specific temperature range under the above conditions, the charging efficiency and the heat generation reduction characteristics can be maximized.

[0174] If only one of the first magnetic unit and the second magnetic unit is used, or if the arrangement of the first magnetic unit and the second magnetic unit is changed, then T1 60 and T2 60 As a result, the temperature continues to rise and high-temperature heat is generated, which may cause deformation and damage to the device structure.

[0175] Furthermore, when the coil unit receives wireless power with a frequency of 85 kHz and an output of 6.6 kW for 60 minutes, the temperature (T1 60 ) and the temperature on the upper side of the second magnetic unit (T2 60 ) can be 1°C to 15°C. If T1 60 and T2 60 If the difference between them is too large, the magnetic flux during wireless charging will be improperly distributed, so that the generated heat cannot be effectively transferred to the outside, and it is easy to be damaged by external impact during vehicle driving.

[0176] For example, T1 60 and T2 60 The difference (absolute value) between may be 1°C to 15°C, 1°C to 12°C, 2°C to 12°C, 3°C to 12°C or 5°C to 12°C.

[0177] In addition, if Figure 3b and 3d As shown, if the first magnetic unit is a three-dimensional structure and the second magnetic unit is in contact with the shielding unit, then T2 60 Can be lower than T1 60 . Specifically, T2 60 Can be compared to T1 60 The temperature is lower by about 1°C to 10°C, 1°C to 9°C, 1°C to 8°C, 2°C to 8°C, 3°C to 7°C, 4°C to 7°C or 5°C to 7°C. As described above, since the second magnetic unit that generates more heat than the first magnetic unit during wireless charging is arranged to contact the shielding unit, the magnetic flux density and heat dissipation can be effectively distributed to increase the wireless charging efficiency, and the heat generated by the second magnetic unit can be dissipated to the outside through the shielding unit to improve the heat dissipation characteristics.

[0178] In addition, T1 60 Can be compared to T1 10 High 50℃ to 100℃, T2 60 Can be compared to T2 10 50°C to 100°C higher. Specifically, T1 60 Can be compared to T110 High 50℃ to 90℃, 50℃ to 85℃ or 50℃ to 80℃, T2 60 Can be compared to T2 10 50℃ to 100℃, 50℃ to 90℃, 50℃ to 80℃ or 50℃ to 70℃. 60 and T1 10 The difference between 60 and T2 10 If the difference between the two exceeds 100°C, the heat generated by fast charging and high-power wireless charging will increase, which may limit their use due to safety issues.

[0179] In addition, in a wireless charging device, such as Figure 3b and 3d As shown in FIG. 1 , if the first magnetic unit is a three-dimensional structure and the second magnetic unit is in contact with the shielding unit, compared with Figure 3a and 3c In the case where the first magnetic unit is a planar structure and the second magnetic unit does not contact the shielding unit, the heat dissipation effect and charging efficiency can be further improved. Figure 3b and 3d As shown, if the first magnetic unit is a three-dimensional structure and the second magnetic unit is in contact with the shielding unit, then T1 60 and T1 10 The difference between and / or T2 60 and T2 10 The difference between can be 50℃ to 80℃ respectively. On the other hand, if Figure 3a and 3c As shown, if the first magnetic unit is a planar structure or if the second magnetic unit does not contact the shielding unit, then T1 60 and T1 10 The difference between and / or T2 60 and T2 10 The difference between them can be greater than 80°C to 100°C, respectively.

[0180] The thermal conductivity of the second magnetic unit may be 0.1W / m·K to 6W / m·K higher than that of the first magnetic unit. For example, the thermal conductivity of the second magnetic unit may be 0.1W / m·K to 6W / m·K, 0.5W / m·K to 5W / m·K, or 1W / m·K to 4W / m·K higher than that of the first magnetic unit. In this case, since the second magnetic unit having a higher thermal conductivity than the first magnetic unit is disposed adjacent to the shielding unit, the heat generated during wireless charging can be effectively dispersed by the distribution of magnetic flux, and the durability can be improved to resist external impact or deformation.

[0181] Arrangement of the second magnetic unit

[0182] Since the second magnetic unit generates more heat than the first magnetic unit during wireless charging, it is preferably disposed close to the shielding unit. For example, if a ferrite-based magnetic material is used as the second magnetic unit, the ferrite base will generate a large amount of heat, but it can dissipate heat very well. Therefore, since the second magnetic unit having such a heat generation is disposed close to the shielding unit, the characteristic of reducing heat generation can be further improved. If the first magnetic unit including a polymer-type magnetic material having a low heat generation is disposed close to the shielding unit, the polymer component included in the polymer-type magnetic material will store heat, causing the temperature to continue to rise over time, thereby adversely affecting the characteristic of reducing heat generation.

[0183] Specifically, see Figures 3a to 3d The second magnetic unit (500) can be arranged above the first magnetic unit (300), that is, between the first magnetic unit (300) and the shielding unit (400). Since the second magnetic unit having a greater heat generation than the first magnetic unit is arranged close to the shielding unit, the high magnetic flux density around the coil unit can be effectively dispersed, thereby not only improving the charging efficiency, but also effectively dispersing the heat concentrated near the coil unit, compared with the case of using the first magnetic unit alone.

[0184] In this case, if Figure 3b and 3d As shown, at least part of the second magnetic unit (500) can be in contact with the shielding unit (400). As a result, the heat generated in the second magnetic unit can be effectively released through the shielding unit. For example, when the second magnetic unit is in the form of a sheet, one side thereof can be in contact with the shielding unit as a whole. Specifically, the second magnetic unit can be attached to the side of the shielding unit facing the first magnetic unit. More specifically, the second magnetic unit can be attached to one side of the shielding unit by a thermally conductive adhesive to further enhance the heat dissipation effect. The thermally conductive adhesive can include a thermally conductive material such as a metal-based, carbon-based or ceramic-based adhesive, for example, an adhesive resin in which thermally conductive particles are dispersed.

[0185] like Figure 3a As shown, the second magnetic unit (500) can be disposed on both the outer portion (310) and the central portion (320) of the first magnetic unit. Figures 3b to 3d As shown, the second magnetic unit (500) can be arranged only on the outside (310) of the first magnetic unit. As a result, the high magnetic flux density around the coil unit can be effectively dispersed, thereby improving the charging efficiency compared to the case where the first magnetic unit is used alone. Alternatively, the second magnetic unit can be arranged to cover at least part of the outside and center of the first magnetic unit.

[0186] The second magnetic unit may be configured to be combined with or separated from the first magnetic unit.

[0187] As an example, the second magnetic unit may be in contact with the first magnetic unit. Figures 3b to 3d , the second magnetic unit (500) may be attached to the outside of the first magnetic unit (300).

[0188] Alternatively, the first magnetic unit and the second magnetic unit may be arranged to be spaced apart from each other. Specifically, the second magnetic unit may be spaced apart from the first magnetic unit between the shielding unit and the first magnetic unit. As a result, the magnetic flux may be distributed between the first magnetic unit and the second magnetic unit, and the heat generated thereby may be appropriately adjusted. In addition, it may be made to have a certain degree of durability to resist external forces such as impact or deformation to which the electric vehicle is subjected during driving.

[0189] For example, the spacing between the first magnetic unit and the second magnetic unit 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. Specifically, the shortest spacing between the first magnetic unit and the second magnetic unit may be 1 mm to 20 mm. More specifically, the shortest spacing between the first magnetic unit and the second magnetic unit may be 3 mm to 10 mm. Within the above range, it can help to distribute the magnetic flux gathered during wireless charging, help control the heat generated thereby, and can give it a certain durability to resist the external forces applied during vehicle driving.

[0190] Alternatively, see Figure 3d , a groove may be provided on a surface of the first magnetic unit (300) facing the shielding unit (400), and the second magnetic unit (500) may be inserted into the groove.

[0191] In this case, since the first magnetic unit can be used as a shell of the second magnetic unit, the second magnetic unit can be fixed without a separate adhesive or structure. In particular, since the first magnetic unit can be molded into a three-dimensional structure by a mold using a polymer type magnetic material using magnetic powder and an adhesive resin, a groove for inserting the second magnetic unit can be easily formed.

[0192] In this case, at least part of the first magnetic unit and the second magnetic unit may be in contact with the shielding unit. As a result, heat generated in the first magnetic unit and / or the second magnetic unit may be effectively released through the shielding unit.

[0193] The depth of the groove formed on the first magnetic unit may be the same as or different from the thickness (height) of the second magnetic unit. If the depth of the groove is the same as the thickness of the second magnetic unit, the first magnetic unit and the second magnetic unit may contact the shielding unit at the same time. Alternatively, if the depth of the groove is less than the thickness of the second magnetic unit, only the second magnetic unit may contact the shielding unit. On the other hand, if the depth of the groove is greater than the thickness of the second magnetic unit, only the first magnetic unit may contact the shielding unit.

[0194] In addition, see Figure 3a and 3c The second magnetic unit (500) may be arranged to be separated from the shielding unit (400) by a preset interval. In addition, an empty space or a partition may be further included between the second magnetic unit (500) and the shielding unit (400). The material and structure of the partition may be the material and structure of a conventional partition used for a wireless charging device.

[0195] Composition and characteristics of cooling unit

[0196] The wireless charging device as described in the embodiment may further include a heat dissipation unit for effective heat transfer. During wireless charging, a large amount of heat generated in the magnetic unit is proportional to the amount of concentrated magnetic flux and the magnetic permeability loss. The heat dissipation unit can effectively transfer the heat generated in the magnetic unit to the outside.

[0197] The heat dissipation unit may be in a sheet shape, that is, the heat dissipation unit may be a heat sink.

[0198] The heat dissipation unit may include an adhesive resin and a heat dissipation filler dispersed in the adhesive resin. As described above, since the heat dissipation unit includes a polymer component, it can provide adhesion between the shielding unit and the magnetic sheet. In addition, it can prevent the magnetic unit from being damaged due to external impact.

[0199] Examples of the binder resin include polyimide resin, polyamide resin, polycarbonate resin, acrylonitrile-butadiene-styrene (ABS) resin, polypropylene resin, polyethylene resin, polystyrene resin, polyphenylene sulfide (PPS) resin, polyether etherketone (PEEK) resin, silicone resin, acrylic resin, polyurethane resin, polyester resin, isocyanate resin and epoxy resin, but are not limited thereto.

[0200] For example, the binder resin may be a curable resin. Specifically, the binder resin may be a photocurable resin and / or a thermosetting resin. In particular, it may be a resin that exhibits adhesiveness when cured. More specifically, the resin that may be used as the binder resin may include at least one functional group or part that is capable of thermal curing, 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 part that can be cured by active energy, such as an epoxy group, a cyclic ether group, a thioether group, an acetal group, or a lactone group. Such a functional group or part may be, for example, an isocyanate group (-NCO), a hydroxyl group (-OH), or a carboxyl group (-COOH).

[0201] As a specific example, the binder resin may be one or more of a silicon-based resin and an acrylic-based resin.

[0202] In addition, the heat dissipation filler can be one or more of ceramic particles, carbon particles and metal particles. The ceramic particles can include metal oxides or nitrides. Specifically, they can include silicon dioxide, aluminum oxide, boron nitride, aluminum nitride, magnesium oxide, etc. The carbon particles can include stone mill, carbon black, carbon nanotubes, etc. The metal particles can include copper, silver, iron, nickel, etc.

[0203] The content of the heat dissipation filler in the heat dissipation unit may be 70% to 90% by weight, 70% to 85% by weight, or 75% to 90% by weight.

[0204] The heat dissipation unit may have a thermal conductivity of 0.5 W / m·K to 30 W / m·K, specifically, 2 W / m·K to 5 W / m·K.

[0205] The thickness of the heat dissipation unit may be 0.1 mm to 5 mm, specifically, 0.1 mm to 3 mm or 0.2 mm to 1 mm.

[0206] The area of ​​the heat dissipation unit may be the same as or different from that of the first magnetic unit or the second magnetic unit. For example, if the heat dissipation unit is disposed outside the first magnetic unit, the area of ​​the heat dissipation unit corresponds to the area of ​​the outside. In addition, if the heat dissipation unit is disposed between the second magnetic unit and the shielding unit, the area of ​​the heat dissipation unit corresponds to the area of ​​the second magnetic unit. As a result, even a heat dissipation unit of a small area can have excellent heat dissipation characteristics, adhesion and impact resistance.

[0207] Arrangement of cooling unit

[0208] The heat dissipation unit is arranged between the magnetic unit and the shielding unit. The heat dissipation unit may contact the magnetic unit and the shielding unit at the same time. Specifically, the heat dissipation unit may adhere to the magnetic unit and the shielding unit. More specifically, the heat dissipation unit may contact the second magnetic unit and the shielding unit at the same time. In addition, it may adhere to the second magnetic unit and the shielding unit. As a result, the heat generated in the second magnetic unit can be easily released to the outside through the heat dissipation unit.

[0209] like Figure 5a As shown, the second magnetic unit (500) can be arranged on the first magnetic unit (300), and the heat dissipation unit (700) can contact the second magnetic unit (500) and the shielding unit (400) at the same time. Since the second magnetic unit with a higher magnetic permeability than the first magnetic unit is arranged close to the shielding unit, the high magnetic flux density around the coil unit can be effectively dispersed, thereby not only improving the charging efficiency, but also effectively dispersing the heat concentrated near the coil unit compared to the case of using the first magnetic unit alone. In addition, in this article, the heat generated in the second magnetic unit can be effectively transferred to the shielding unit through the heat dissipation unit.

[0210] For example, when the second magnetic unit is sheet-shaped, one side thereof can be integrally attached to the shielding unit via the heat dissipation unit. Specifically, the second magnetic unit can be attached to a side of the shielding unit facing the first magnetic unit via the heat dissipation unit.

[0211] In addition, the second magnetic unit (500) and the heat dissipation unit (700) can be arranged on the outside (310) of the first magnetic unit. As a result, the magnetic flux density concentrated near the coil unit can be dispersed, and the heat generated near the coil unit can be effectively released to the outside.

[0212] like Figure 5b As shown, the first magnetic unit (300) has a groove on its surface facing the shielding unit (400), the second magnetic unit (500) is inserted into the groove, and the heat dissipation unit (700) can contact the first magnetic unit (300) and at least one of the second magnetic unit (500) and the shielding unit (400) at the same time.

[0213] In this case, since the first magnetic unit can be used as a shell of the second magnetic unit, the second magnetic unit can be fixed without a separate adhesive or structure. In particular, since the first magnetic unit can be molded into a three-dimensional structure by using a mold of a polymer-type magnetic material including magnetic powder and an adhesive resin, a groove for inserting the second magnetic unit can be easily formed. In addition, in this article, the heat generated in the first magnetic unit and / or the second magnetic unit can be effectively transferred to the shielding unit through the heat dissipation unit.

[0214] The depth of the groove formed on the first magnetic unit may be the same as or different from the thickness (height) of the second magnetic unit. If the depth of the groove is the same as the thickness of the second magnetic unit, the heat dissipation unit may contact the first magnetic unit, the second magnetic unit, and the shielding unit at the same time. Alternatively, if the depth of the groove is less than the thickness of the second magnetic unit, the heat dissipation unit may only contact the second magnetic unit and the shielding unit. On the other hand, if the depth of the groove is greater than the thickness of the second magnetic unit, the heat dissipation unit may only contact the first magnetic unit and the shielding unit.

[0215] like Figure 5c As shown, the second magnetic unit (500) may be disposed to be embedded in the first magnetic unit (300), and the heat dissipation unit (700) may contact the first magnetic unit (500) and the shielding unit (400) at the same time.

[0216] Even in this case, since the first magnetic unit can be used as a shell of the second magnetic unit, the second magnetic unit can be fixed without a separate adhesive or structure. In particular, since the first magnetic unit can be molded into a three-dimensional structure using a mold of a polymer-type magnetic material using magnetic powder and an adhesive resin, a structure for embedding the second magnetic unit can be easily formed. In addition, in this article, the heat generated by the first magnetic unit can be effectively transferred to the shielding unit through the heat dissipation unit.

[0217] tray

[0218] like Figures 6 to 9b As shown, the wireless charging device (10) may further include a tray (800) disposed between the first magnetic unit (300) and the shielding unit (400). Specifically, the wireless charging device (10) as described in the embodiment may further include a tray (800) disposed between the first magnetic unit (300) and the second magnetic unit (500).

[0219] The tray can be used not only as a housing for fixing the second magnetic unit, but also as a partition for separating the second magnetic unit from the first magnetic unit. That is, the second magnetic unit can be arranged to be separated from the first magnetic unit by the tray.

[0220] The tray may include a seat groove for accommodating the second magnetic unit. As a result, the second magnetic unit may be arranged to be placed in the seat groove. In this case, since the tray may be used as a housing for the second magnetic unit, the second magnetic unit may be fixed without a separate adhesive or structure. For example, the depth of the seat groove formed in the tray may be the same as or different from the thickness (height) of the second magnetic unit. In addition, if a heat dissipation unit is further provided on the second magnetic unit, the depth of the seat groove formed in the tray may be the same as the sum of the thicknesses of the second magnetic unit and the heat dissipation unit.

[0221] In addition, the tray can be in contact with the shielding unit. Specifically, the tray can be fixed to the lower part of the shielding unit. In addition, it can also be arranged to contact the first magnetic unit (for example, the outside of the first magnetic unit).

[0222] Alternatively, the tray may be arranged to be spaced apart from the shielding unit or the first magnetic unit at a preset interval. For example, the spacing between the tray and the shielding unit or the spacing between the tray and the first magnetic unit (e.g., the outside of the first magnetic unit) may be 0.5 mm or more or 1 mm or more, specifically, 0.5 mm to 5 mm or 1 mm to 3 mm.

[0223] The tray may be made of a plastic material. Specifically, it may be made of a heat-resistant plastic material. Specifically, the plastic material may be a thermoplastic polyimide. In addition, the glass transition temperature (Tg) of the plastic material may be 230°C to 360°C, specifically, about 250 to 310°C.

[0224] In addition, the tray may further include a heat dissipation filler. In this case, the material of the heat dissipation filler may be at least one selected from a ceramic-based material, an oxide-based material, and a carbon-based material. More specifically, it may be at least one selected from Al2O3, AlN, SiO2, and Si3N4. As a result, the heat generated in the first magnetic unit or the second magnetic unit may also be transferred to the shielding unit through the tray.

[0225] Support unit

[0226] like Figure 1a and 1b As shown, the wireless charging device (10) further includes a support unit (100) for supporting the coil unit (200). The material and structure of the support unit can be the material and structure of a conventional support unit for a wireless charging device. The support unit can be a flat plate structure or a structure having a groove conforming to the shape of the coil formed thereon to fix the coil unit.

[0227] shell

[0228] like Figure 1a and 1b As shown, the wireless charging device (10) according to the embodiment further includes a housing (600) for accommodating the above components.

[0229] The housing enables components such as the coil unit, the shielding unit, and the magnetic unit to be properly arranged and installed. The material and structure of the housing may be the material and structure of a conventional housing for a wireless charging device. It may be properly designed according to the components used therein.

[0230] Charging efficiency

[0231] At the same time, the wireless charging device of the present invention can effectively reduce heat generation and improve charging efficiency during high-power wireless charging of 3kW to 22kW, 4kW to 20kW or 5kW to 18kW. Therefore, it can be advantageously used for high-power wireless charging.

[0232] In particular, since the magnetic unit of the wireless charging device adopts a three-dimensional structure, the charging efficiency and the heat generation can be further improved.

[0233] For example, the charging efficiency of the wireless charging device as described in the embodiment may be 85% or more, 88% or more, 89% or more, 90% or more, or 91% or more.

[0234] Therefore, the wireless charging device according to the embodiment can be advantageously used in mobile tools that require large-capacity power transmission between a transmitter and a receiver, such as electric vehicles.

[0235] Mobile Tools

[0236] Fig.11 A mobile tool is shown, specifically, a mobile tool provided with a wireless charging device. Since the mobile tool has a wireless charging device on its lower side, wireless charging can be performed in a parking lot equipped with an electric vehicle wireless charging system.

[0237] See also Fig.11 The mobile tool (1) as described in the embodiment includes the wireless charging device as described in the embodiment as a receiver (21). The wireless charging device can be used as a wireless charging receiver of the mobile tool (1) and can receive power from the transmitter (22) for wireless charging.

[0238] As described above, the mobile tool includes the wireless charging device, and the configuration of the wireless charging device is as described above.

[0239] Specifically, the wireless charging device provided in the mobile tool includes a coil unit; a shielding unit provided on the coil unit; and a magnetic unit including a first magnetic unit and a second magnetic unit and provided between the coil unit and the shielding unit, wherein the magnetic permeability of the second magnetic unit is greater than that of the first magnetic unit at 85kHz.

[0240] The configuration and characteristics of each component of the wireless charging device employed in the mobile tool are as described above.

[0241] The mobile tool further includes a battery for receiving power from the wireless charging device. The wireless charging device can wirelessly receive power and transmit it to the battery, and the battery can power the drive system of the electric vehicle. The battery can be charged by power transmitted by the wireless charging device or other additional wired charging devices.

[0242] In addition, the mobile tool may further include a signal transmitter for transmitting information related to charging to the transmitter of the wireless charging system. Such information related to charging may be charging efficiency, such as charging speed, charging status, and the like.

[0243] Embodiments for carrying out the invention

[0244] Hereinafter, examples will be described, but the implementation scope is not limited thereto.

[0245] Example 1: Manufacturing of a wireless charging device

[0246] Step 1: Preparation of the first magnetic unit - three-dimensional structure

[0247] 42.8 parts by weight of magnetic powder, 15.4 parts by weight of polyurethane resin dispersion (polyurethane resin accounts for 25% by weight and 2-butanone accounts for 75% by weight), 1.0 parts by weight of isocyanate-based curing agent dispersion (isocyanate-based curing agent accounts for 62% by weight, n-butyl acetate accounts for 25% by weight and 2-butanone accounts for 13% by weight), 0.4 parts by weight of epoxy resin dispersion (epoxy resin accounts for 70% by weight, n-butyl acetate accounts for 3% by weight, 2-butanone accounts for 15% by weight and toluene accounts for 12% by weight) and 40.5 parts by weight of toluene are mixed in a planetary mixer and stirred at a speed of about 40-50 rpm for about 2 hours to prepare a magnetic powder slurry.

[0248] like Fig.10 As shown, the magnetic powder slurry is injected into a mold (3) by an injection molding machine (2) to give it a three-dimensional structure (corresponding to the outside of the coil: 9 mm, the center part surrounded by the outside: 1 mm). It is dried at a temperature of about 160°C to obtain a first magnetic unit (polymer type magnetic material) having a three-dimensional structure.

[0249] Step 2: Preparation of hybrid magnetic materials

[0250] A ferrite-based magnetic material (PC-95 ferrite magnetic sheet manufactured by TDK Co., Ltd.) with a thickness of 1 mm as the second magnetic unit is arranged on the outside of the first magnetic unit prepared in step 1, which corresponds to the coil unit, and then hot-pressed and bonded to obtain a hybrid magnetic material.

[0251] Step 3: Fabrication of the Wireless Charging Device

[0252] like Figure 3bAs shown, the hybrid magnetic material prepared in step 2 is combined with a support unit, a coil unit, a partition, a shielding unit and a housing to obtain a wireless charging device. Herein, one side of the second magnetic unit (ferrite-based magnetic material) on both sides of the hybrid magnetic material faces the shielding unit.

[0253] Example 2: Manufacturing of wireless charging device

[0254] Step 1: Preparation of the first magnetic unit - planar structure

[0255] The magnetic powder slurry prepared in step 1 of Example 1 is applied to a carrier film by a notch wheel coater and dried at a temperature of about 110°C to form a polymer magnetic material. The polymer magnetic material sheet is obtained by compressing and hardening it by a hot pressing process at a temperature of about 170°C and a pressure of about 9 MPa for about 60 minutes. The content of magnetic powder in the sheet is about 90%, and the thickness of a single sheet is about 100 μm. 40 to 50 sheets of the above sheets are laminated to obtain a first magnetic unit with a thickness of about 4 mm.

[0256] Step 2: Preparation of hybrid magnetic materials

[0257] A ferrite-based magnetic material (PC-95 ferrite magnetic sheet manufactured by TDK Co., Ltd.) with a thickness of 1 mm as a second magnetic unit was placed on the first magnetic unit prepared in step 1, and then thermally pressed to obtain a hybrid magnetic material (thickness of 5 mm).

[0258] Step 3: Fabrication of the Wireless Charging Device

[0259] like Figure 3a As shown, the hybrid magnetic material prepared in step 2 is combined with a support unit, a coil unit, a partition, a shielding unit and a housing to obtain a wireless charging device. Herein, one side of the second magnetic unit (ferrite-based magnetic material) on both sides of the hybrid magnetic material faces the shielding unit.

[0260] Comparative Example 1: Manufacturing of a Wireless Charging Device

[0261] A planar polymer type magnetic material (first magnetic unit) with a thickness of 5 mm was prepared in the same manner as step 1 of Example 2, and was combined with a support unit, a coil unit, a partition, a shielding unit, and a housing to obtain a wireless charging device.

[0262] Comparative Example 2: Manufacturing of Wireless Charging Device

[0263] A ferrite-based magnetic material (PC-95 ferrite magnetic sheet manufactured by TDK Co., Ltd.) having a thickness of 5 mm was combined with a support unit, a coil unit, a partition plate, a shield unit, and a housing to obtain a wireless charging device.

[0264] Test Example 1: Measurement of Magnetic Unit Surface Temperature

[0265] When the coil unit received wireless power with a frequency of 85 kHz and an output of 6.6 kW for 10 minutes or 60 minutes, the surface temperatures of the first and second magnetic units of the wireless charging devices manufactured in the examples and comparative examples were measured under the SAE J2954 WPT2 Z2 class standard test charging efficiency measurement conditions.

[0266] The surface temperature of the lower and upper sides of the magnetic unit was measured using the T / GUARD 405-system manufactured by Qualitrol. Specifically, for Examples 1 and 2, Figure 3a and 3b As shown, the temperatures of the upper and lower sides of the hybrid magnetic material, i.e., the temperatures of the lower side (P1) of the first magnetic unit (300) and the upper side (P2) of the second magnetic unit are measured respectively. In addition, for Comparative Example 1, the temperatures of the lower and upper sides of the first magnetic unit are measured respectively. For Comparative Example 2, the temperatures of the lower and upper sides of the second magnetic unit are measured respectively.

[0267] The measurement results of the surface temperature of the magnetic unit are summarized as follows and shown in Table 1.

[0268] -T1 10 (°C): Temperature of the lower side (P1) of the first magnetic unit when the coil unit receives wireless power for 10 minutes (or the temperature of the lower side of the second magnetic unit of Comparative Example 2)

[0269] -T2 10 (°C): Temperature of the upper side (P2) of the second magnetic unit when the coil unit receives wireless power for 10 minutes (or the temperature of the upper side of the first magnetic unit of Comparative Example 1)

[0270] -T1 60 (°C): Temperature of the lower side (P1) of the first magnetic unit when the coil unit receives wireless power for 60 minutes (or the temperature of the lower side of the second magnetic unit of Comparative Example 2)

[0271] -T2 60 (°C): Temperature of the upper side (P2) of the second magnetic unit when the coil unit receives wireless power for 60 minutes (or the temperature of the upper side of the first magnetic unit of Comparative Example 1)

[0272] In addition, specific temperature measurement positions on the lower and upper sides of the first magnetic unit are set at the center point area of ​​the coil unit (200) where the wire exists (ie, the center point of the outer part (310) of the first magnetic unit).

[0273] Test Example 2: Measurement of Charging Efficiency

[0274] The charging efficiency was measured using the SAE J2954 WPT2 Z2 class standard measurement method. Specifically, a device with a coil unit and a frame under the SAE J2954 WPT2 Z2 class standard test specification was used, and the magnetic unit, the partition, and the aluminum plate were stacked to prepare a transmitter (75cm×60cm). The wireless charging devices in the examples and comparative examples were used as receivers (35cm×35cm), respectively. The charging efficiency was measured at a frequency of 85kHz and an output of 6.6kW.

[0275] The results are shown in Table 1 below.

[0276] [Table 1]

[0277]

[0278] As shown in Table 1, compared with the wireless charging devices in Comparative Examples 1 and 2 that use the first magnetic unit or the second magnetic unit alone, in the wireless charging devices in Examples 1 and 2 that use a hybrid magnetic material, the magnetic flux density and heat dissipation can be effectively distributed, thereby improving the wireless charging efficiency, wherein the hybrid magnetic material combines the first magnetic unit and the second magnetic unit with different heat generation amounts and the second magnetic unit is arranged to be close to the shielding unit.

[0279] Specifically, when the coil unit receives wireless power for 10 minutes, the temperature (T1 10 ) is lower than the temperature on its upper side (T2 10 ) is about 1°C to 3°C, while in the wireless charging devices of Comparative Examples 1 and 2, the temperature of the lower side of the magnetic unit (T1 10 ) and its upper temperature (T2 10 )same.

[0280] Meanwhile, in the wireless charging devices of Examples 1 and 2, when the coil unit receives wireless power for 60 minutes, the temperature (T1 60 ) and the temperature above it (T2 60 ) does not exceed 180°C, and the difference between the two (i.e., T1 60 and T2 60 The difference between T1 and T2 does not exceed 15°C. In addition, in the wireless charging devices of Examples 1 and 2, when the coil unit receives wireless power for 10 minutes and 60 minutes, the temperature change (ie, from T1 to T2) is not more than 15°C.10 To T1 60 Changes and changes from T2 10 To T2 60 The change of temperature shall not exceed 100℃.

[0281] In addition, compared with the wireless charging device of Example 2, in the wireless charging device of Example 1, when the coil unit receives wireless power for 60 minutes, the temperature is significantly reduced. In particular, since the first magnetic unit of the wireless charging device of Example 1 adopts a three-dimensional structure, the temperature (T2 60 ) is lower than the temperature (T1 60 ) was about 6°C lower, confirming the optimal fever reduction effect.

[0282] In contrast, in the wireless charging device of Comparative Example 1, all the temperatures of the magnetic unit (ie, T1 10 、T2 10 、T1 60 and T2 60 )) are significantly higher than Examples 1 and 2, confirming the increase in heat generation. In addition, in the wireless charging device of Comparative Example 2, since only ferrite magnetic sheets are used, its impact resistance may be deteriorated, it may have problems of increased weight and cost, and it requires a separate frame to attach and install the magnetic unit, which is disadvantageous.

Claims

1. A wireless charging device, comprising a coil unit; a shielding unit disposed on the coil unit; and a magnetic unit comprising a first magnetic unit and a second magnetic unit and disposed between the coil unit and the shielding unit, wherein: The second magnetic unit is disposed on the first magnetic unit, the magnetic permeability of the second magnetic unit is higher than the magnetic permeability of the first magnetic unit at 85 kHz, and the thermal conductivity of the second magnetic unit is 0.1 W / m·K to 6 W / m·K higher than the thermal conductivity of the first magnetic unit; Wherein, the thickness of the second magnetic unit is 0.5 mm to 5 mm; The thickness of the second magnetic unit is thinner than that of the first magnetic unit; At 85 kHz, a difference in magnetic permeability between the second magnetic unit and the first magnetic unit is 500 or more.

2. The wireless charging device according to claim 1, wherein: When the coil unit receives wireless power from the outside, more heat is generated in the second magnetic unit than in the first magnetic unit.

3. The wireless charging device according to claim 2, wherein: When the coil unit receives wireless power with a frequency of 85 kHz and an output of 6.6 kW for 10 minutes, the temperature T1 of the lower side of the first magnetic unit 10 T2 than the temperature of the upper side of the second magnetic unit 10 1℃ or more lower.

4. The wireless charging device according to claim 3, wherein: When the coil unit receives wireless power with a frequency of 85kHz and an output of 6.6kW for 60 minutes, the temperature T1 of the lower side of the first magnetic unit 60 and the temperature T2 of the upper side of the second magnetic unit 60 The difference between them is 1°C to 15°C.

5. The wireless charging device according to claim 4, wherein: The temperature T1 of the lower side of the first magnetic unit 60 T1 than the temperature of the lower side of the first magnetic unit 10 50°C to 100°C higher, and the temperature T2 on the upper side of the second magnetic unit 60 T2 than the temperature of the upper side of the second magnetic unit 10 50℃ to 100℃ higher.

6. The wireless charging device according to claim 1, wherein: The wireless charging device also includes a heat dissipation unit arranged between the shielding unit and the magnetic unit, the first magnetic unit includes an outer portion corresponding to the portion where the coil unit is arranged; and a central portion surrounded by the outer portion, and the thickness of the outer portion is greater than the thickness of the central portion.

7. The wireless charging device according to claim 6, wherein: The heat dissipation unit includes an adhesive resin and a heat dissipation filler dispersed in the adhesive resin, and the heat dissipation unit is adhered to the magnetic unit and the shielding unit.

8. The wireless charging device according to claim 6, wherein: The magnetic permeability of the first magnetic unit at 85 kHz is 5 to 300, and the magnetic permeability of the second magnetic unit at 85 kHz is 1000 to 5000.

9. The wireless charging device according to claim 6, wherein: The second magnetic unit and the heat dissipation unit are disposed on the outer portion of the first magnetic unit.

10. The wireless charging device according to claim 6, wherein: The heat dissipation unit contacts the second magnetic unit and the shielding unit simultaneously.

11. The wireless charging device according to claim 1, wherein: The second magnetic unit is thermally connected to the shielding unit.

12. The wireless charging device according to claim 11, wherein: The first magnetic unit and the second magnetic unit are spaced apart from each other, and a shortest distance between the first magnetic unit and the second magnetic unit is 1 mm to 20 mm.

13. The wireless charging device according to claim 11, wherein: The wireless charging device further includes a tray disposed between the first magnetic unit and the second magnetic unit, the tray includes a seat groove for accommodating the second magnetic unit, and the tray is fixed to a lower portion of the shielding unit.

14. A mobile tool, comprising a wireless charging device, wherein: The wireless charging device includes a coil unit; a shielding unit disposed on the coil unit; and a magnetic unit including a first magnetic unit and a second magnetic unit and disposed between the coil unit and the shielding unit, wherein the second magnetic unit is disposed on the first magnetic unit, the magnetic permeability of the second magnetic unit is higher than the magnetic permeability of the first magnetic unit at 85kHz, and the thermal conductivity of the second magnetic unit is 0.1W / m·K to 6W / m·K higher than the thermal conductivity of the first magnetic unit; Wherein, the thickness of the second magnetic unit is 0.5 mm to 5 mm; The thickness of the second magnetic unit is thinner than that of the first magnetic unit; At 85 kHz, a difference in magnetic permeability between the second magnetic unit and the first magnetic unit is 500 or more.

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