Shielding structure for wireless charging system

Abstract

This disclosure relates to a "shielding structure for a wireless charging system." Specific embodiments described herein provide systems and methods for wireless charging. In one embodiment, a portable electronic device includes a housing, a planar inductor coil, and a ferromagnetic shield. The planar inductor coil is disposed within the housing and includes a conductive wire wound multiple times around a central point with an increasing radius. The ferromagnetic shield is disposed within the housing and overlaps with the planar inductor coil. The ferromagnetic shield includes: a first layer comprising a first plurality of iron-based nanocrystal strips arranged in adjacent rows along a first direction; and a second layer comprising a second plurality of iron-based nanocrystal strips overlapping the first layer. The second plurality of iron-based nanocrystal strips are arranged in adjacent rows along a second direction different from the first direction.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 167,815, entitled “SHIELDING STRUCTURES FOR WIRELESSCHARGING SYSTEMS”, filed on March 30, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] Various aspects of this disclosure relate to systems and methods for wireless charging, and more specifically to managing magnetic flux in a wireless charging system using a shielding structure. Background Technology

[0004] Many portable electronic devices, such as smartphones, tablets, smartwatches, and personal computers, are battery-powered. These devices can incorporate wireless charging circuitry to recharge their batteries, allowing for charging without cables. However, wireless charging systems may experience energy loss during charging, reducing charging efficiency. Summary of the Invention

[0005] The specific embodiments described and claimed herein address the foregoing by providing systems and methods for wireless charging. In one embodiment, a portable electronic device includes a housing, a planar inductor coil, and a ferromagnetic shield. The planar inductor coil is disposed within the housing and includes a conductive wire wound multiple times around a central point with an increasing radius. The ferromagnetic shield is disposed within the housing and overlaps with the planar inductor coil. The ferromagnetic shield includes: a first layer comprising a first plurality of iron-based nanocrystal strips arranged in adjacent rows along a first direction; and a second layer comprising a second plurality of iron-based nanocrystal strips overlapping the first layer. The second plurality of iron-based nanocrystal strips are arranged in adjacent rows along a second direction different from the first direction.

[0006] In another embodiment, a portable electronic device includes a housing, a planar inductor coil, and a ferromagnetic shield. The planar inductor coil is disposed within the housing and includes a conductive wire wound multiple times around a central point with increasing radius. The ferromagnetic shield is disposed within the housing and overlaps with the planar inductor coil. The ferromagnetic shield includes a substrate and multiple wires comprising an iron-based nanocrystalline material. The multiple wires are disposed on the substrate. Each of the multiple wires extends radially outward from a common region of the substrate to define a two-dimensional radial pattern.

[0007] In another embodiment, a magnetic component includes a first layer and a second layer. The first layer includes a first plurality of iron-based nanocrystal strips arranged in adjacent rows along a first direction. The second layer includes a second plurality of iron-based nanocrystal strips overlapping the first layer. The second plurality of iron-based nanocrystal strips are arranged in adjacent rows along a second direction different from the first direction.

[0008] In another embodiment, a magnetic component includes a substrate and a plurality of wires. The plurality of wires comprise an iron-based nanocrystalline material. The plurality of wires are disposed on the substrate. Each of the plurality of wires extends radially outward from a common region of the substrate to define a two-dimensional radial pattern.

[0009] Other specific embodiments are also described and illustrated herein. Furthermore, while several specific embodiments are disclosed, other specific embodiments of the technology disclosed herein will become apparent to those skilled in the art from the following detailed description illustrating and describing exemplary specific embodiments of the technology disclosed herein. As will be appreciated, modifications may be made to the technology disclosed herein in various aspects without departing from the spirit and scope of the technology disclosed herein. Therefore, the drawings and detailed descriptions are to be regarded substantially as illustrative rather than restrictive. Attached Figure Description

[0010] Figure 1 An exploded view of an exemplary portable electronic device including an exemplary ferromagnetic shield is shown.

[0011] Figure 2 A side view of a ferromagnetic shield including an exemplary stack of laminated nanocrystals is shown.

[0012] Figure 3A A top view of an exemplary first nanocrystal layer of a laminated nanocrystal stack is shown.

[0013] Figure 3B A top view of an exemplary second nanocrystal layer of a laminated nanocrystal stack is shown.

[0014] Figure 3C A top view of an exemplary nanocrystal strip of the first nanocrystal layer is shown.

[0015] Figure 4 Another exemplary ferromagnetic shielding device containing nanowires is shown.

[0016] Figure 5 Nanowires arranged in an exemplary two-dimensional radial pattern are shown.

[0017] Figure 6A graph showing the inductance versus frequency of a magnetic material placed on one side of a test coil according to the technique disclosed in this invention, wherein the frequency is in the range of 10 kHz to 3 MHz.

[0018] Figure 7 A graph showing the loss factor Q of a magnetic material placed on one side of a test coil as a function of frequency, in the range of 10 kHz to 3 MHz, is shown according to the technique disclosed in this invention.

[0019] Figure 8 A graph showing the inductance versus frequency of a magnetic material placed on both sides of a test coil according to the technique disclosed in this invention, wherein the frequency is in the range of 10 kHz to 3 MHz.

[0020] Figure 9 A graph showing the loss factor Q of a magnetic material placed on both sides of a test coil as a function of frequency, in the range of 10 kHz to 3 MHz, is shown according to the technique disclosed in this invention. Detailed Implementation

[0021] The aspects of the technology disclosed in this invention relate to systems and methods for managing magnetic flux in a wireless charging system. Battery-powered portable electronic devices can support wireless charging as an alternative to or supplement to wired charging. For example, a portable electronic device can be wirelessly charged when positioned on a charging surface of a wireless charging device. A transmitter coil disposed below the charging surface generates magnetic flux, which induces a current in a corresponding receiving coil in a wireless power receiver of the portable electronic device. The wireless power receiver rectifies the induced current and applies the resulting power for battery charging and / or other device operation. The technology disclosed in this invention reduces energy loss during wireless charging.

[0022] In one aspect, a magnetic component includes one or more nanocrystalline shielding structures that manage magnetic flux during wireless charging of a portable electronic device. The magnetic component may be disposed within a housing of the portable electronic device. The portable electronic device includes an inductor coil overlapping the nanocrystalline shielding structure. The inductor coil may be disposed within the housing and includes conductive wire wound multiple turns around a central point with increasing radius, such that the inductor coil is substantially planar. The nanocrystalline shielding structure can at least partially form a ferromagnetic shield with low eddy current losses over a high operating frequency range. The nanocrystalline shielding structure may be formed using an iron-based nanocrystalline material.

[0023] The nanocrystalline shielding structure may include one or more layers, each layer being formed of multiple nanocrystalline strips. Each nanocrystalline strip includes multiple grains. The nanocrystalline strips may contain cracked nanocrystalline material with air gaps formed between adjacent grains and / or between nanocrystalline strips. The presence of air gaps and multiple grains manages magnetic flux during wireless charging to reduce eddy current losses and permeability.

[0024] The nanocrystalline shielding structure may include multiple lines arranged in one or more two-dimensional radial patterns on a substrate. Each two-dimensional radial pattern may be defined by multiple lines extending outward from a common region of the substrate. The nanocrystalline lines provide high in-plane permeability in a plane parallel to the substrate and low through-plane permeability in a direction perpendicular to the substrate. The nanocrystalline lines manage magnetic flux without eddy current losses during wireless charging.

[0025] To begin a detailed description of the exemplary portable electronic device 100, refer to Figure 1 Portable electronic device 100 is an electronic device that includes a rechargeable power source such as a battery. Portable electronic device 100 can be specifically designed to perform various functions for a user. In one particular implementation, portable electronic device 100 is a consumer electronic device, such as a smartphone, tablet computer, laptop computer, smartwatch, etc.

[0026] Portable electronic device 100 includes electronic components that operate using a power source. The power source for portable electronic device 100 may include a battery for releasing stored energy to power the electronic components of portable electronic device 100. In one embodiment, to supplement the energy released to power the electronic components, portable electronic device 100 includes a wireless charging system. In some examples, the wireless charging system is a bidirectional wireless charging system that both wirelessly receives and wirelessly transmits power.

[0027] like Figure 1 As shown, the portable electronic device 100 includes a housing surrounding internal components within an internal cavity. The housing may be formed of a top housing 126 and a bottom housing 125. In one embodiment, the internal components include a wireless power module 101, a coil 105, an electromagnetic shield 106, a ferromagnetic shield 110, a thermal shield 115, and an adhesive component 120. The wireless power module 101 may include a device detection coil 108 positioned around the periphery of the electromagnetic shield 106.

[0028] In one embodiment, an electromagnetic shield 106 is positioned in front of the coil 105 such that magnetic flux passes through the electromagnetic shield 106 before reaching the coil 105. For example, when the coil 105 operates as a receiver coil, magnetic flux passes through the electromagnetic shield 106, and when the coil 105 operates as a transmitter coil, magnetic flux is directed toward the electromagnetic shield 106. An exemplary electromagnetic shield 106 is positioned between the coil 105 and the housing 125. In one embodiment, the electromagnetic shield 106 may be a shielding layer that is substantially transparent to magnetic flux, allowing a large amount of magnetic flux to pass through. The electromagnetic shield 106 may also be substantially opaque to electric fields, such that electric fields generated during operation are substantially blocked by the electromagnetic shield 106. Any voltage generated in the electromagnetic shield 106 due to the blocking of electric fields can be discharged to ground. Blocking electric fields can mitigate noise originating from voltage build-up on the coil 105. The electromagnetic shield 106 may be made of any material suitable for blocking electric fields while allowing electromagnetic fields to pass through, such as a thin layer of silver.

[0029] The thermal shield 115 may include a thermal insulation layer (e.g., graphite) that provides thermal isolation between the wireless power module 101, the battery, and other components of the portable electronic device 100 in which the wireless power module 101 is incorporated. The thermal shield 115 may also include a copper layer that is connected to a ground and helps to provide thermal shielding while capturing stray magnetic flux.

[0030] The adhesive component 120 attaches the wireless power module 101 to the housing 125. In one embodiment, the adhesive component 120 comprises one or more sheets of adhesive material. For example, the adhesive component 120 may comprise a single sheet of adhesive material such as pressure-sensitive adhesive (PSA) that attaches the wireless power module 101 to the housing 125. In one embodiment, the wireless power module 101 is attached to the housing 125 within a cutout region 130, the size and shape of which are configured to receive the wireless power module 101. The cutout region 130 thus saves space within the internal cavity and minimizes the thickness of the portable electronic device 100. The electromagnetic shield 106 and the adhesive component 120 may include a central opening corresponding to the inner diameter of the coil 105.

[0031] Coil 105 may include one or more inductor coils configured to interact with and / or generate magnetic flux. In one embodiment, the inductor coil of coil 105 includes a conductive wire wound around a central point with multiple turns of increasing radius, such that the inductor coil is substantially planar. In other words, the conductive wire is wound in a helical configuration from the inner diameter to the outer diameter, such that the overall shape is a planar inductor coil formed by multiple turns of patterned lines on a flexible substrate. Termination ends located in the inner diameter of the inductor coil may be guided to the outer diameter by means of conductive traces. A charging circuit may be coupled to the inductor coil at an edge location to operate coil 105 to correspondingly transmit and / or receive power.

[0032] exist Figure 1 In one example, the portable electronic device 100 includes a heat shield 115 disposed adjacent to a ferromagnetic shield 110 on a first side of a coil 105, and an electromagnetic shield 106 disposed opposite to the heat shield 115 and the ferromagnetic shield 110 on a second side of the coil 105. The ferromagnetic shield 110 may be formed using a nanocrystalline material as described herein.

[0033] In one embodiment, a ferromagnetic shield 110 is positioned between the coil 105 and the thermal shield 115. The ferromagnetic shield 110 acts as a magnetic field shield to direct magnetic flux toward the coil 105, thereby improving charging efficiency. In doing so, the ferromagnetic shield 110 also serves to direct stray magnetic flux away from non-coil regions of the portable electronic device 100, which may have internal components sensitive to magnetic flux. An exemplary ferromagnetic shield 110 includes one or more nanocrystalline shielding structures.

[0034] In one embodiment, the nanocrystalline shielding structure of the ferromagnetic shield 110 includes one or more nanocrystalline layers. The nanocrystalline layers may be arranged in an overlapping relationship. Each nanocrystalline layer includes a plurality of nanocrystalline strips arranged relative to each other. For example, a first nanocrystalline layer may include a first plurality of nanocrystalline strips arranged in adjacent rows along a first direction, and a second nanocrystalline layer may include a second plurality of nanocrystalline strips arranged in adjacent rows along a second direction. The first and second directions may be different. For example, the first direction may be perpendicular to the second direction.

[0035] Nanocrystalline ribbons can be formed from cracked nanocrystalline material. For example, a nanocrystalline ribbon may comprise multiple grains having a small size (e.g., ranging from about 1 μm to 2 μm in width). In one embodiment, such fine grains in the nanocrystalline ribbon are formed by rolling a strip of nanocrystalline material under mechanical pressure to form cracked nanocrystalline material. During this process, air gaps are formed between the grains. Air gaps may also exist between adjacent nanocrystalline ribbons in a shielding structure. The cracked nanocrystalline material of the nanocrystalline ribbon has low eddy current losses and reduced permeability. More specifically, due to the presence of air gaps and the formation of fine grains in the cracked nanocrystalline material, eddy current losses at high operating frequencies can be significantly reduced.

[0036] In one embodiment, the nanocrystalline layers comprising the cracked nanocrystalline ribbons each form a sheet (e.g., with a thickness in the range of 14 μm to 20 μm), wherein the grains elongate in a plane along a first direction (e.g., a horizontal direction, such as the X or Y direction). The resulting ferromagnetic shield 110 structure has high in-plane permeability in the first direction and low through-plane permeability in a second direction (e.g., a vertical direction, such as the Z direction perpendicular to the XY plane). The nanocrystalline material has very high permeability in the first direction, for example, greater than 10,000 H / m.

[0037] Compared to soft ferrites and similar materials, nanocrystalline materials can be iron-based, offering optimized metallic properties, including high conductivity. Iron-based nanocrystalline materials exhibit high magnetic field (B) saturation (e.g., greater than 1 Tesla) compared to soft ferrite materials. Therefore, iron-based nanocrystalline materials operate well in permanent magnet environments such as direct current (DC) magnetic fields. However, at some wireless power transmission operating frequencies, nanocrystalline materials can exhibit high eddy current losses. For example, consider that implementations of the Wireless Power Consortium Qi standard for wireless power transmission typically operate at around 100 kHz to 120 kHz, with some specific implementations extending to 200 kHz and 400 kHz. Wireless charging typically operates at frequencies ranging from around 100 kHz to 360 kHz. Notably, eddy current losses in nanocrystalline materials are significantly higher at higher operating frequencies of 200 kHz and above, relative to operating frequencies of 100 kHz to 200 kHz. In a specific implementation of the nanocrystalline shielding structure of the ferromagnetic shielding component 110, the cracked nanocrystalline strips with air gaps between the fine grains reduce eddy current losses at the relevant operating frequencies of the portable electronic device 100. Eddy current losses decrease as the grain size decreases. The permeability also decreases due to the air gaps added between the fine grains.

[0038] In one embodiment, the nanocrystalline shielding structure of the ferromagnetic shield 110 includes multiple lines comprising nanocrystalline material disposed on a substrate (e.g., a planar substrate). The multiple lines can be arranged on the substrate in one or more two-dimensional patterns, such as radial patterns. In some examples, each line extends radially outward from a common region of the substrate to define a two-dimensional radial pattern extending outward from a central region. Multiple two-dimensional radial patterns can be formed and disposed above each other in such a way that the lines of each two-dimensional radial pattern do not overlap. Examples of nanocrystalline shielding structures including nanocrystalline lines have high in-plane permeability (e.g., 10,000 H / m or greater) in a plane parallel to the substrate, and significantly lower through-plane permeability (e.g., 10 H / m or less) in a direction perpendicular to the substrate. Nanocrystalline shielding structures comprising multiple lines made of nanocrystalline material have no eddy current losses or have negligible eddy current losses.

[0039] Overall, the ferromagnetic material of the ferromagnetic shield 110 remains unsaturated during operation of the portable electronic device 100 to wirelessly receive power using a planar inductor coil at wireless power operating frequencies of approximately 100 kHz to 400 kHz. The ferromagnetic material of the ferromagnetic shield 110 remains unsaturated during operation of the portable electronic device 100 to wirelessly receive power using a planar inductor coil at a rated power level of at least 15 watts.

[0040] Go to Figure 2 The image shows a side view of an exemplary nanocrystal shielding structure 200 comprising a stack of nanocrystals. In one embodiment, the nanocrystal shielding structure 200 includes a top layer 202, a bottom layer 208, and one or more metal foils 206 (e.g., 206A-206C) interleaved with one or more dielectric layers 204. The top layer 202 and the bottom layer 208 may each be a plastic film formed of polyethylene terephthalate (PET) or a similar material. The dielectric layers 204 may be formed of an adhesive such as PSA, epoxy resin, fiberglass reinforced epoxy resin, etc.

[0041] The metal foil 206 may form one or more nanocrystalline layers. In one embodiment, the top layer 202 is disposed above the top dielectric layer of the dielectric layer 204, while the bottom layer 208 is positioned below the bottom dielectric layer of the dielectric layer 204. The metal foil 206 may be formed of an iron-based nanocrystalline material. The nanocrystalline shielding structure 200 may include any number of metal foils 206, such as one, two, three, four, five, six, or seven, etc.

[0042] Figure 3AA top view of a first metal foil 206A is shown. In one embodiment, the first metal foil 206A includes a first plurality of nanocrystal strips 302 arranged in adjacent rows in a first direction. For example, the first direction may be aligned with the X-direction. A top view of a second metal foil 206B is also shown. Figure 3B As can be understood, the second metal foil 206B includes a second plurality of nanocrystal strips 304 arranged in adjacent rows aligned along a second direction, such as the Y direction. The first direction may be different from the second direction. For example, the first direction may be perpendicular to the second direction. The second plurality of nanocrystal strips 304 of the second metal foil 206B may adhere to the first metal foil 206A.

[0043] It should be understood that metal foil 206 may include additional metal foils. For example, metal foil 206 may include a third metal foil 206C bonded to the second metal foil 206B. The third metal foil 206C includes a third plurality of nanocrystalline strips aligned with the X direction. More layers may be added in a similar manner to obtain layers of metal foil 206 arranged in alternating directions in the stack of shielding structure 200. For example, odd-numbered layers of metal foil 206 may be aligned with the X direction, while even-numbered layers of metal foil 206 may be aligned with the Y direction, or vice versa. In this arrangement, the metal foils 206 are firmly bonded together. The arrangement of the nanocrystalline strips may be varied similarly within metal foil 206. For example, nanocrystalline strips in odd-numbered layers may be aligned at 45° with the X direction, while nanocrystalline strips in even-numbered layers may be aligned at 90° with nanocrystalline strips in odd-numbered layers.

[0044] In one embodiment, each of the first plurality of nanocrystal strips 302 has a common first width, and each of the second plurality of nanocrystal strips 304 has a common second width. The first common width and the second common width may be different or the same. In another embodiment, the first plurality of nanocrystal strips 302 and / or the second plurality of nanocrystal strips 304 include strips of different widths. Each metal foil in the metal foil 206 may have a layer thickness of less than 25 μm. For example, each metal foil in the metal foil 206 may have a layer thickness in the range of about 5 μm to 25 μm. In one example, the layer thickness is 5 μm or greater. In another example, the layer thickness is 10 μm or greater. In another example, the layer thickness is 15 μm or greater. In another example, the layer thickness is 20 μm or greater. Similarly, in one example, the layer thickness is 25 μm or less. In another example, the layer thickness is 20 μm or less. In another example, the layer thickness is 15 μm or less. In another example, the layer thickness is 10 μm or less. In a non-limiting example, each of the metal foils 206 may be about 22 μm thick, each of the dielectric layers 204 may be about 3 μm thick, and each of the top layer 202 and the bottom layer 208 may be about 5 μm thick. When the number of metal foils 206 is four, the nanocrystal shielding structure 200 may have a total thickness of about 105 μm and dimensions of about 5 cm wide × about 5 cm long.

[0045] See Figure 3C The image shows a top view of an exemplary nanocrystalline strip 306 of a metal foil 206. In one embodiment, the nanocrystalline strip 306 is made of a cracked nanocrystalline material. More specifically, the nanocrystalline strip 306 includes a plurality of air gaps 308 disposed between a plurality of grains 310. For example, at least two or more adjacent grains 310 may be separated by air gaps 308. Each of the plurality of grains 306 may be small, for example, having an average grain size in the range of about 1 nm to 1 μm. Thus, one or more strips, such as a first plurality of nanocrystalline strips 302, a second plurality of nanocrystalline strips 304, etc., may be cracked between the plurality of grains 310. Air gaps 308 may be further disposed between adjacent cracked nanocrystalline strips.

[0046] The nanocrystalline ribbon 306 of the metal foil 206 can be formed by rotation and rapid cooling followed by stretching. The nanocrystalline ribbon 306 can have a thickness ranging from about 15 μm to 30 μm. In one example, the nanocrystalline ribbon 306 comprises a polycrystalline material with a grain size of less than 100 nm. The nanocrystalline ribbon 306 can be iron-based. Such iron-based nanocrystalline materials of the nanocrystalline ribbon 306 provide optimized magnetic properties. For example, the nanocrystalline ribbon 306 can have a high permeability (e.g., 10,000 to 15,000) relative to the permeability of ferrite (e.g., 3,000). The nanocrystalline ribbon 306 can also have a high in-plane permeability (e.g., in the XY plane) relative to a lower through-plane permeability (e.g., in the Z direction perpendicular to the XY plane). For example, the nanocrystalline ribbon 306 can have a permeability of less than 10 in the Z direction. The nanocrystalline ribbon 306 may contain 8.0 wt% to 9.4 wt% silicon (Si), 4.8 wt% to 6.4 wt% niobium (Nb), 1.0 wt% to 2.2 wt% boron (B) and 0.80 wt% to 2.20 wt% copper (Cu), with iron (Fe) as the balance.

[0047] In one embodiment, the nanocrystalline material sheet is cut into strips prior to rolling. For example, the strips may be about 1 cm to 2 cm wide. Rolling and cracking can be accomplished using rollers at room temperature. The cracked nanocrystalline material is rolled to form a nanocrystalline strip 306, wherein air gaps 308 are formed between grains 310. The rolling pattern and pressure of the rollers can vary depending on the level of cracking. The degree of cracking in the nanocrystalline strip 306 can be measured by the degree of magnetic permeability. The rolled strip reduces the magnetic permeability in the resulting cracked nanocrystalline material. The cracked nanocrystalline material may have a reduced magnetic permeability of about 200, significantly lower than that of the nanocrystalline material sheet, which may have, for example, a magnetic permeability of 10,000 to 15,000.

[0048] In one embodiment, the cracked nanocrystalline material of the nanocrystalline ribbon 306 is annealed at a high temperature in the range of about 300°C to 550°C to produce optimized magnetic properties. Annealing promotes the alignment of grains 310. For example, the nanocrystalline ribbon 306 may be annealed at a first temperature (e.g., 300°C) for a first time period (e.g., 1 hour) and annealed at a second temperature (e.g., 450°C) above the first temperature for a second time period (e.g., 1 hour).

[0049] The grain size of the cracked nanocrystalline material of the nanocrystalline ribbon 306 can be about 50 nm or smaller. In one example, the grain size is 40 nm or smaller. In another example, the grain size is 30 nm or smaller. In another example, the grain size is 20 nm or smaller. In another example, the grain size is 10 nm or smaller. In another example, the grain size is 5 nm or smaller. In another example, the grain size is 1 nm or smaller. The nanocrystalline ribbon 306 can have a thickness in the range of about 10 μm to 25 μm. The nanocrystalline ribbon 306 can have a thickness of about 7.0 g / cm³. 3 Or even higher densities. In one example, nanocrystal strip 306 has a density of 7.1 g / cm³. 3 Or even higher densities. In another example, nanocrystalline strip 306 has a density of 7.2 g / cm³. 3 Or even higher densities. In another example, nanocrystalline strip 306 has a density of 7.3 g / cm³. 3 Or a higher density.

[0050] The nanocrystalline shielding structure 200 may have an in-plane permeability in the range of about 100 to 300 in its plane. In one example, the nanocrystalline shielding structure 200 has an in-plane permeability of 300 or less in its plane. In another example, the nanocrystalline shielding structure 200 has an in-plane permeability of 250 or less in its plane. In yet another example, the nanocrystalline shielding structure 200 has an in-plane permeability of 200 or less in its plane. In yet another example, the nanocrystalline shielding structure 200 has an in-plane permeability of 150 or less in its plane.

[0051] Similarly, in one example, the nanocrystalline shielding structure 200 has an in-plane permeability of 100 or greater in its plane. In another example, the nanocrystalline shielding structure 200 has an in-plane permeability of 150 or greater in its plane. In yet another example, the nanocrystalline shielding structure 200 has an in-plane permeability of 200 or greater in its plane. In yet another example, the nanocrystalline shielding structure 200 has an in-plane permeability of 250 or greater in its plane.

[0052] The nanocrystalline shielding structure 200 may have a permeability of 10 or less in the direction perpendicular to its surface. In one example, the nanocrystalline shielding structure 200 has a permeability of 5 or less in the direction perpendicular to its surface. In another example, the nanocrystalline shielding structure 200 has a permeability of 3 or less in the direction perpendicular to its surface. In yet another example, the nanocrystalline shielding structure 200 has a permeability of 1 or less in the direction perpendicular to its surface.

[0053] As described herein, the portable electronic device 100 is operable to receive wireless power transmissions in a frequency range of approximately 100 kHz to 300 kHz. The ferromagnetic material of the nanocrystalline shielding structure 200 remains unsaturated during operation of the portable electronic device 100 to wirelessly receive power using the coil 105 at a rated power level of at least 15 watts. As used herein, rated power refers to the maximum wireless power level under which an electronic device such as the portable electronic device 100 is rated to operate. For example, in conjunction with the Wireless Power Consortium Qi standard, electronic devices using a base power curve are typically rated for 5-watt operation, and electronic devices using an extended power curve are typically rated for 15-watt operation.

[0054] Go to Figures 4 to 5 In one embodiment, the ferromagnetic shield 110 is formed of a nanocrystalline shielding structure 400, which includes multiple lines (e.g., nanowires) arranged in one or more patterns on a substrate 402. The substrate 402 may be planar. The patterns may each be two-dimensional patterns, such as two-dimensional radial patterns with a certain angle.

[0055] In one embodiment, the nanocrystal shielding structure 400 includes a first plurality of nanocrystal wires 404. Each nanocrystal wire 404 has a first end 406A and a second end 406B. The first end 406A of each nanocrystal wire 404 is connected to a common region 408 on a substrate 402. Two adjacent nanocrystal wires 404 may be separated by a first angle 410. Each nanocrystal wire 404 extends radially outward from the common region 408 in a plane to form a first two-dimensional radial pattern 412.

[0056] In one embodiment, the nanocrystal shielding structure 400 may include a second plurality of nanocrystal lines 504 defining a second two-dimensional radial pattern 500, such as from... Figure 5As can be understood. In one specific implementation, the first two-dimensional radial pattern 412 is positioned above the second two-dimensional radial pattern 500, and the first plurality of nanocrystal lines 404 do not overlap with the second plurality of nanocrystal lines 504. For example... Figure 5 As shown, each of the second plurality of nanocrystal wires 504 has a first end 506A and a second end 506B. The first end 506A of each nanocrystal wire 504 is connected to a second common region 508 of the substrate 402 and extends radially outward from the second common region 508 in a plane to form a second two-dimensional radial pattern 500. Two adjacent nanocrystal wires 504 are separated by a second angle 510. The second two-dimensional radial pattern 500 may be disposed above the first two-dimensional radial pattern 412. The second common region 508 of the second two-dimensional radial pattern 500 may be aligned with the common region 408 of the first two-dimensional radial pattern 412. The second two-dimensional radial pattern 500 may be offset from the first two-dimensional radial pattern 412 at a certain angle.

[0057] In one embodiment, the first plurality of lines 404 do not overlap with the second plurality of lines 504. The common region 408 may overlap with the center point of the coil 105. In one embodiment, the second common region 508 may overlap with the common region 408. The first angle 410 between two adjacent nanocrystal lines of the first two-dimensional radial pattern 412 may be a first constant. The second angle 510 between two adjacent nanocrystal lines of the second two-dimensional radial pattern 500 may be a second constant. The first angle 410 may be different from the second angle 510. Each line in the second plurality of lines 504 defining the second two-dimensional radial pattern 500 is equidistant from its adjacent lines.

[0058] In one embodiment, nanocrystal wires 404 and 504 comprise nanocrystal material. The two-dimensional radial patterns 412 and 500 have a high permeability of approximately 10,000 to 15,000 in the radial direction, such that the nanocrystal shielding structure 400 has a high planar permeability (e.g., in the XY plane) relative to a low through-plane permeability (e.g., in the Z direction perpendicular to the XY plane). For example, the nanocrystal shielding structure 400 may have a permeability of 10 or less in the Z direction. The nanocrystal shielding structure 400 has an in-plane permeability of 10,000 or greater and a through-plane permeability of 10 or less. The ferromagnetic shield 110 formed by the nanocrystal shielding structure 400 has no eddy current losses or has negligible eddy current losses.

[0059] As described herein, the portable electronic device 100 is operable to receive wireless power transmission at frequencies ranging from approximately 100 kHz to 300 kHz. The ferromagnetic material of the nanocrystalline shielding structure 400 remains unsaturated during operation of the portable electronic device 100 to wirelessly receive power using the coil 105 at a rated power level of at least 15 watts.

[0060] In one specific embodiment, the nanocrystal wires of the nanocrystal shielding structure 400 have a diameter ranging from about 0.1 mm to 1.0 mm. In one example, the nanocrystal wires have a diameter of 1.0 mm or less. In another example, the nanocrystal wires have a diameter of 0.7 mm or less. In another example, the nanocrystal wires have a diameter of 0.5 mm or less. In another example, the nanocrystal wires have a diameter of 0.3 mm or less. Similarly, in one example, the nanocrystal wires have a diameter of 0.1 mm or less. In another example, the nanocrystal wires have a diameter of 0.3 mm or less. In another example, the nanocrystal wires have a diameter of 0.5 mm or less. In another example, the nanocrystal wires have a diameter of 0.7 mm or less. The nanocrystal wires of the nanocrystal shielding structure 400 may contain 8.0 wt% to 9.4 wt% Si, 4.8 wt% to 6.4 wt% Nb, 1.0 wt% to 2.2 wt% B and 0.80 wt% to 2.20 wt% Cu, with Fe as the balance.

[0061] See Figures 6 to 9 Various examples of the techniques disclosed in this invention are provided. It should be understood that the examples and results are merely illustrative and are not intended to be limiting. L and Q tests of magnetic materials were performed using an E4990A impedance analyzer from 10 kHz to 3 MHz with L and Q scans. Tests were performed using magnetic materials placed on one side of the test coil, and then using magnetic materials placed on both sides of the test coil.

[0062] Table 1 lists the tested samples. Samples 2-6 exhibit reduced permeability due to cracking. Sample 6 has the lowest permeability of 200 and the largest cracking among all samples 2-6. Sample 1 does not exhibit cracking.

[0063] Table 1

[0064]

[0065]

[0066] Figure 6 The graph shows the inductance versus frequency of a magnetic material placed on one side of a test coil. Figure 6As shown, the inductance Ls of all materials remains flat until approximately 1 MHz. The inductance Ls also decreases with increasing cracking, as can be understood by comparing sample 1 with samples 2–6. Due to its higher permeability than ferrite, sample 1 (nanocrystalline material) has a higher inductance than samples 8–10 (ferrite).

[0067] Figure 7 It shows Figure 6 The graph shows the loss factor Q versus frequency for the magnetic materials. As can be understood by comparing sample 1 (nanocrystalline material) with samples 8-10 (ferrite), the ferrite material results in higher losses than the nanocrystalline material. For the same material, a larger size of 1 mm results in higher losses than a smaller size of 0.1 mm, as shown in samples 2 to 7 of Fe-based nanocrystalline materials with the same cracking. As cracking increases, samples 2-6 show that the peak value of the loss factor Q shifts to a higher frequency with increasing cracking and decreasing permeability.

[0068] Figure 8 The graph shows the inductance versus frequency of the magnetic materials placed on both sides of the test coil. Figure 8 As shown, the inductance Ls of all materials remains flat until approximately 1 MHz. Furthermore, the inductance Ls remains flat until approximately 1 MHz. The inductance Ls decreases with increasing cracking, as shown in the comparison between sample 1 and samples 2-6. Due to its higher permeability relative to ferrite, sample 1 (nanocrystalline material) has a higher inductance than samples 8-10 (ferrite).

[0069] Figure 9 It shows Figure 8 The graph shows the loss factor Q versus frequency for the magnetic materials. As shown, the peak value of the loss factor Q for samples 1-6 shifts to a higher frequency with increasing cracking and decreasing permeability. Although a similar trend was observed as with magnetic materials placed on one side, the inductance and loss factor values ​​differed for magnetic materials placed on both sides.

[0070] Table 2 lists the inductance (Ls), loss factor (Q), and resistance (R) values ​​of the cracked soft magnetic nanocrystal sample, namely sample 6 (MS200-0.1 mm), at various operating frequencies ranging from 100 kHz to 500 kHz. Values ​​for the magnetic material placed on one or both sides of the coil are shown.

[0071] Table 2

[0072]

[0073] Table 3 lists the Ls, Q, and R values ​​of samples 1 and 6 (MS200-0.1mm) with magnetic materials placed on both sides at different frequencies. It should be noted that at the same frequency, the resistance of sample 1 is much higher than that of sample 6, while the loss factor Q of sample 1 is lower than that of sample 6.

[0074] Table 3

[0075]

[0076] Any ranges referenced herein include the extreme values. The terms “substantially” and “about” as used throughout this specification are used to describe and indicate small fluctuations. For example, these terms may refer to ±5%.

[0077] It should be understood that the specific order or hierarchical structure of the steps in the methods disclosed in this invention is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchical structure of the steps in the methods may be rearranged while remaining within the scope of the subject matter disclosed in this invention. The appended method claims present elements of various steps in the sample order and are not necessarily limited to the specific order or hierarchical structure presented.

[0078] While this disclosure has been described with reference to various specific embodiments, it should be understood that these embodiments are exemplary and the scope of this disclosure is not limited to these specific embodiments. Many variations, modifications, additions, and improvements are possible. More generally, embodiments according to this disclosure have been described in the context of specific embodiments. In the various embodiments of this disclosure, functions may be separated or combined in a frame in different ways, or described in different terms. These and other variations, modifications, additions, and improvements may fall within the scope of this disclosure as defined in the following claims.

Claims

1. A portable electronic device, comprising: shell; A planar inductor coil, the planar inductor coil being disposed within the housing and comprising a conductive wire wound around a central point with multiple turns of increasing radius; as well as A ferromagnetic shielding element, disposed within the housing and overlapping the planar inductor coil, the ferromagnetic shielding element comprising: A first layer, the first layer comprising a first plurality of iron-based nanocrystal strips arranged in adjacent rows along a first direction; and The second layer includes a second plurality of iron-based nanocrystal strips overlapping the first layer, the second plurality of iron-based nanocrystal strips being arranged in adjacent rows along a second direction different from the first direction, wherein the ferromagnetic shielding has an in-plane permeability of at least 10,000 and a through-plane permeability of less than 10.

2. The portable electronic device according to claim 1, wherein, The second direction is perpendicular to the first direction.

3. The portable electronic device according to claim 1, wherein, Each of the first plurality of iron-based nanocrystal strips has a common first width, and each of the second plurality of iron-based nanocrystal strips has a common second width.

4. The portable electronic device according to claim 1, wherein, Each of the first plurality of iron-based nanocrystal strips includes a plurality of grains, wherein at least two adjacent grains are separated by an air gap.

5. The portable electronic device according to claim 1, wherein, One or more of the first plurality of iron-based nanocrystal strips are formed from cracked nanocrystal material.

6. A magnetic component, comprising: The first layer includes a first plurality of iron-based nanocrystal strips arranged in adjacent rows along a first direction; and The second layer includes a second plurality of iron-based nanocrystal strips overlapping the first layer. The second plurality of iron-based nanocrystal strips are arranged in adjacent rows along a second direction different from the first direction. The first plurality of iron-based nanocrystal strips and the second plurality of iron-based nanocrystal strips form a ferromagnetic shield having an in-plane permeability of at least 10,000 and a through-plane permeability of less than 10.

7. The magnetic component according to claim 6, wherein, The second direction is perpendicular to the first direction.

8. The magnetic component according to claim 6, wherein, Each of the first plurality of iron-based nanocrystal strips has a common first width, and each of the second plurality of iron-based nanocrystal strips has a common second width.

9. The magnetic component according to claim 8, wherein, The common first width and the common second width are different.

10. The magnetic component according to claim 6, wherein, At least one of the first plurality of iron-based nanocrystal strips or the second plurality of iron-based nanocrystal strips includes strips of different widths.

11. The magnetic component according to claim 6, wherein, The ferromagnetic material of the ferromagnetic shield remains unsaturated during operation of the portable electronic device, enabling the planar inductor coil of the portable electronic device to wirelessly receive power at wireless power operating frequencies from 100 kHz to 400 kHz.

12. The magnetic component according to claim 11, wherein, The ferromagnetic material of the ferromagnetic shield remains unsaturated during operation of the portable electronic device, enabling the planar inductor coil to wirelessly receive power at a rated power level of at least 15 watts.

13. The magnetic component according to claim 6, wherein, The first plurality of iron-based nanocrystal bands have an average grain size of 1 nm to 100 nm.

14. The magnetic component according to claim 6, wherein, Each of the first plurality of iron-based nanocrystal strips includes a plurality of grains, wherein at least two adjacent grains are separated by an air gap.

15. The magnetic component according to claim 6, wherein, One or more of the first plurality of iron-based nanocrystal strips are formed from cracked nanocrystal material.

16. The magnetic component of claim 6, further comprising an adhesive disposed on at least one of the first layer or the second layer.

17. The magnetic component of claim 6 further comprises a dielectric layer adhered between the first layer and the second layer.

18. The magnetic component according to claim 6, wherein, Each of the first and second layers has a thickness of 25µm or less.

19. The magnetic component according to claim 6, wherein, The first plurality of iron-based nanocrystal ribbons and the second plurality of iron-based nanocrystal ribbons comprise from 8.0 wt% to 9.4 wt% of Si, from 4.8 wt% to 6.4 wt% of Nb, from 1.0 wt% to 2.2 wt% of B, and from 0.80 wt% to 2.20 wt% of Cu, with Fe as the balance.

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