HK1229062A1 - Wireless charging coil - Google Patents

Abstract

A wireless charging coil is provided herein. More specifically, provided herein is a wireless charging coil comprising a first stamped coil having a first spiral trace, the first spiral trace defining a first space between windings, and a second stamped coil having a second spiral trace, the second spiral trace defining a second space between windings, the first stamped coil and second stamped coil in co-planar relation, the first stamped coil positioned within the second space of the second stamped coil, and the second stamped coil positioned within the first space of the first stamped coil, the first and second coils electronically connected and an adhesive covering and surrounding the first stamped coil and the second stamped coil to bond the coils together and to insulate the coils.

Description

Wireless charging coil

Technical Field

The present disclosure relates to wireless charging coils and methods for making the same. More particularly, the present disclosure relates to a series connected wireless charging coil that is two-wire wound in parallel.

Background

Wireless power transfer is the transfer of electrical power from a base station (that transfers power) to a mobile device (that consumes power) by electromagnetic induction (inductive power) and/or resonant frequency methods. Wireless power transfer is becoming increasingly popular in mobile devices and especially in smart phones. A popular standard for inductive charging technology is the Qi interface standard developed by the wireless power consortium, which has several protocols that allow for wireless transfer of electrical power between electronic devices. Other standards may utilize electromagnetic induction or resonant frequencies to wirelessly charge the device. The mobile device (or any other electronic device) has to meet certain requirements and performance standards in order to be Qi compatible.

Consumers generally want their mobile devices to be small, thin, powerful and efficient, which is often a conflicting goal. More specifically, the charging coil must change material thickness to reduce resistance and improve efficiency. Additionally, maximizing these goals can lead to performance and manufacturing limitations.

What would be desirable, but not yet developed, is a thinner and more efficient wireless charging coil for wireless power transfer between electronic devices.

Disclosure of Invention

The present disclosure relates to wireless charging coils and methods for making the same. More particularly, the present disclosure relates to planar dual-wire parallel-wound series-connected wireless charging coils. The coil has a thinner thickness (e.g., low profile), increased density (e.g., high fill factor), and higher efficiency (e.g., lower resistance) than conventional wireless charging coils.

Drawings

The foregoing features of the present disclosure will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

figure 1 is a schematic diagram showing the process steps for manufacturing a wireless charging coil;

FIG. 2 is a schematic view of a first stamped coil with tie bars (tie bars);

FIG. 3 is a schematic view of a second stamped coil with tie bars;

FIG. 4 is a schematic view of the assembled coil after the tie bars of the first stamped coil and the second stamped coil have been removed;

figure 5 is a schematic diagram of an assembled wireless charging coil with attached jumpers;

FIG. 6 is a close-up view of portion A of FIG. 5;

figure 7 is a schematic diagram of an electrical component assembly including a wireless charging coil and an NFC antenna;

figure 8 is a schematic diagram of an assembled wireless charging coil with a planar two-wire coil;

figure 9 is a cross-sectional view of a portion of the wireless charging coil of figure 8;

figure 10 is a schematic diagram of an assembled wireless charging coil with stacked two-wire coils;

figure 11 is a cross-sectional view of a portion of the wireless charging coil of figure 10;

FIG. 12 is a perspective view of an electrical component assembly;

FIG. 13 is an exploded view of the electrical component assembly of FIG. 12;

fig. 14 is a perspective view of a resonance coil;

fig. 15 is a perspective view of a resonance coil assembly;

FIG. 16 is a perspective view of a folded stamped resonant coil;

FIG. 17 is a partially open perspective view of the coil of FIG. 16;

FIG. 18 is a fully open perspective view of the coil of FIG. 16;

FIG. 19 is an exploded view of the low profile electrical component assembly; and is

FIG. 20 is a perspective view of the fill material of FIG. 19;

figure 21 is a schematic diagram showing the process steps for making a wireless charging coil with adhesive;

FIG. 22 is a partial cross-sectional view of a first stamped coil as applied to a first laminate;

FIG. 23 is a partial cross-sectional view of an assembled coil positioned between a first laminate and a second laminate;

FIG. 24 is a partial cross-sectional view of the assembled coil;

FIG. 25 is a partial top view of the assembled coil of FIG. 24; and is

Fig. 26 is a top view of an assembled coil of the present disclosure.

Detailed Description

The present disclosure relates to wireless charging coils and methods of making the same. As discussed in more detail below in connection with fig. 1-7, a stamped metal wireless charging coil includes a series of parallel traces (trace) connected in a two-wire fashion. In other words, the wireless charging coil includes a first coil and a second coil that are parallel, closely spaced, and connected in series such that the first coil and the second coil have parallel currents. The first and second coils can be stacked or planar and connected in series and/or parallel to meet performance requirements (e.g., electrical requirements, power requirements, etc.). The wireless charging coil can be used in any battery-powered device, particularly in mobile devices (e.g., smart phones, tablets, watches, etc.). The wireless charging coil can be made Qi compatible, but can be adjusted to conform to any wireless transmission protocol. Wireless charging coils with large amounts of conductive material (e.g., copper) can be positioned within a given space by varying (e.g., increasing) the thickness of the coil, which improves energy availability. The wireless charging coils described herein exhibit increased magnetic coupling effectiveness (e.g., magnetic field strength) and thus transfer energy with greater efficiency than other wireless charging coils.

Figure 1 is a schematic diagram illustrating process steps 10 for manufacturing a wireless charging coil of the present disclosure. In step 12, a metal sheet is stamped to form a first coil with tie bars. The metal sheet can be any of a variety of materials suitable for wireless power transmission (e.g., copper alloys, aluminum alloys, etc.). In step 14, a metal sheet (e.g., the same metal sheet or a different metal sheet) is stamped to form a second coil with tie bars. In step 16, the first coil is stamped to remove the tie bars. In step 18, the second coil is stamped to remove the tie bars. In step 20, the first coil and the second coil are assembled together. In step 22, the assembled coil is applied to a ferrite substrate. In step 24, a jumper (e.g., a lead) is attached to electrically connect the first coil and the second coil in series (e.g., an inner end of the first coil is electrically connected with an outer end of the second coil via the jumper).

The above steps can be interchanged, combined or omitted entirely. For example, the coil can be stamped without first forming tie bars, and/or the first and second coils can be applied directly to the ferrite (without first being assembled), and so forth. Furthermore, the coils can be photo-chemically etched or machined instead of stamped or made by any other suitable manufacturing process.

Fig. 2 is a view of a first stamped coil 30 with tie bars. The first coil 30 can be a generally rectangular planar spiral trace 31, although the trace 31 can form any suitable shape (e.g., a circular planar spiral). The dimensions of the coil 30 can vary depending on the application of the coil 30 (e.g., as used in mobile devices, wearable devices, automobiles, etc.). The coil 30 can have any suitable thickness, such as between 0.003 inches and 0.020 inches, etc., but can be thicker for higher powered applications. The coil 30 can have any suitable overall dimension, such as a width between 0.25 inches and 4 inches, and/or a height between 0.25 inches and 4 inches. The traces 31 can also have any suitable dimensions. For example, the width of the traces 31 can be between 0.005 inches and 0.250 inches. The size can vary depending on the physical requirements and performance requirements (e.g., required frequency) of the mobile device. The coil 30 can be made of any suitable material for wireless power transfer (e.g., copper alloy, aluminum alloy, tempered copper alloy (e.g., C110), etc.).

The trace 31 of the coil 30 is rotated about a center any number of times (e.g., 5 times, 10 times, etc.) in order to meet any inductive or resonant power requirements. The trace 31 spirals to form an inner portion 32 in the center of the coil 30. As a result, the coil 30 has an inner end 34 and an outer end 36. The spacing 38 between the traces 31 is configured to be wide enough (e.g., 0.0285 inches) to accommodate a second stamped coil (described in more detail below). The tie bars 40 can be positioned at multiple locations in the spaces 38 to maintain the general shape of the coil 30 (e.g., to prevent unwinding or deformation of the shape), for example, during transportation of the coil 30 between locations or between stations. The outer end 36 can extend outwardly at an angle (e.g., approximately ninety degrees). The inner end 34 and the outer end 36 can be disposed toward the same side of the coil 50, but can be at any of a variety of locations in the coil 50.

Fig. 3 is a view of a second stamped coil 50 with tie bars. The second coil 50 shares most of the same features and characteristics of the first coil shown in fig. 2. The second coil 50 can be a generally rectangular planar spiral trace 51, although the trace 51 can form any suitable shape (e.g., a circular planar spiral). The dimensions of the coil 50 can vary depending on the application of the coil 50 (e.g., as used in mobile devices, wearable devices, automobiles, etc.). The coil 50 can have any suitable thickness, such as between 0.003 inches and 0.020 inches, etc., but can be thicker for higher powered applications. The coil 50 can have any suitable overall dimension, such as a width between 0.25 inches and 4 inches, and/or a height between 0.25 inches and 4 inches. The traces 51 can also have any suitable dimensions. For example, the width of the traces 51 can be between 0.005 inches and 0.250 inches. The size can vary depending on the physical requirements and performance size (e.g., required frequency) of the mobile device. The coil 50 can be made of any suitable material possessing wireless power transfer, such as copper, copper alloys, aluminum alloys, tempered copper alloys (e.g., C110), and the like.

The trace 51 of the coil 50 is rotated about a center any number of times (e.g., 5 times, 10 times, etc.) in order to meet any inductive or resonant power requirements. The trace 51 spirals to form an inner portion 52 in the center of the coil 50. As a result, the coil 50 has an inner end 54 and an outer end 56. The spacing 58 between the traces 51 is configured to be wide enough (e.g., 0.0285 inches) to accommodate the first stamped coil 30 (described above). The tie bars 60 can be positioned at multiple locations in these spacings 58 to maintain the general shape of the coil 50 (e.g., to prevent unwinding or deformation of the shape), for example, during transportation of the coil 50 between locations or between stations. The outer end 56 does not extend outwardly as (but can) extend out of the first coil 30. The inner end 54 and the outer end 56 can be disposed toward the same side of the coil 50, but can be at any of a variety of locations in the coil 50.

Fig. 4 is a view of the assembled coil 170 after the tie bars of the first stamped coil 130 and the second stamped coil 150 have been removed. As shown, the first coil 130 and the second coil 150 are encased within each other. More specifically, the first coil 130 is fitted into the space formed between the traces 151 of the second coil 150, and conversely, the second coil 150 is fitted into the space formed between the traces 131 of the first coil 130. However, when assembled, there is a small gap (e.g., 0.003 inches, 0.004 inches, etc.) between the trace 131 of the first coil 130 and the trace 151 of the second coil 150, as discussed in more detail below. As a result, together with the first coil 130 and the second coil 150, a parallel planar spiral is formed. As shown, the inner end 134 of the first coil 130 is adjacent to the inner end 154 of the second coil 150, and the outer end 136 of the first coil 130 is adjacent to the outer end 156 of the second coil 150. However, the ends can be any relative distance from each other. The stamping process can have an average pitch width variation of at least about 0.003 inches for the assembled coil 170. The maximum variance and the minimum variance depend on the assembled coil 170 dimensions (e.g., overall height and width).

The tight tolerances and rectangular cross-sectional shape of the traces 130, 131 can result in a fill rate (e.g., 85%) that is greater than current industrial coils (e.g., winding coils, etched coils, etc.) (e.g., 65%). For example, a rectangular cross-sectional shape (see fig. 9 below) achieved by stamping provides a potentially higher fill rate than a round cross-sectional shape of a round cable (e.g., a round copper cable). More specifically, a 0.010 inch diameter insulated round cable (0.009 diameter with 0.0005 inch insulation) can provide a 65% fill ratio compared to a stamped coil of rectangular cross section with a 0.006 thickness and 0.003 pitch gap. In addition, the wireless charging coil 170 is capable of operating at higher ambient temperatures than other current industrial cables (e.g., Litz cables) and is not susceptible to degradation by vibration, shock, or heat. This is in part because the wireless charging coil 170 is made of a single piece of conductor (e.g., not a stranded cable). This can be compared to the single strands of Litz cable, which has each separate insulating material in the individual strands that cannot withstand higher temperatures.

Figure 5 is a view of an assembled wireless charging coil 270 with jumper wires attached. Although not shown, a jumper can be attached to the first exterior end 236. As shown, the inner end 234 of the first coil 230 is electrically connected to the outer end 256 of the second coil 250 by a first jumper 274. These ends 234, 256 are relatively close to each other and are disposed on the same side of the coil 270 to allow for a short jumper 274. The second jumper 276 then serves to electrically connect the inner end 254 of the second coil with the mobile device circuitry. The outer end 236 and the inner end 254 are relatively close and disposed toward the same side of the coil 270 to provide a short jumper 276 and for facilitating electrical wiring with the electronic device. The result is a parallel pair of closely spaced coils 230, 250 connected in series such that the first trace 230 and the second trace 250 have parallel currents (e.g., the current of each trace is in the same clockwise or counterclockwise direction).

When fully assembled with other components of the electronic device, the inner portion 272 of the assembled coil 270 is insulated (e.g., by plastic and glue) to ensure proper performance. The assembled wireless charging coil 270 can have any number of windings depending on the electrical requirements. Wireless charging coil 270 can be used in any battery-powered device (e.g., a smartphone). The assembled coil 270 can have any suitable overall dimensions (e.g., 1.142 inches wide and 1.457 inches high, etc.). The coil length can have any suitable length (e.g., 48.459 inches).

Fig. 6 is a close-up view of portion a of fig. 5. As shown, there is a small gap 278 (e.g., air gap) between the trace 231 of the first coil 230 and the trace 251 of the second coil 250 (e.g., 0.003 inches, 0.004 inches, etc.), although there can be an increased gap 280 at the corners to account for the bend in the traces 231, 251 (e.g., making the gap an alternative). These tight tolerances enable greater fill rates than current industrial processes.

The assembled wireless charging coil 270 can provide a Direct Current (DC) resistance (ohms), an Alternating Current (AC) resistance, and/or an AC/DC resistance ratio at a number of different values depending on the size of the charging coil 270 and the material(s) used in the configuration of the charging coil. These values can be adjusted to achieve high AC/DC ratios to meet the induction criteria. The coil dimensions can be varied to achieve varying resistances depending on the desired performance characteristics. For example, for a resistance of 0.232 ohms using the C110 alloy, the traces 230, 250 can have 0.0001234 inches²Can have a cross-section (e.g., 0.005 inch thick and 0.0246 inch wide, or 0.004 inch thick and 0.0308 inch wide, etc.), and the traces 230, 250 can have 0.0000953 inches for a resistance of 0.300 ohms using C110 alloy²E.g., 0.005 inches thick and 0.019 inches wide, or 0.004 inches thick and 0.0238 inches wide, etc.). The stamped wireless charging coil 270 enables high trace thickness and/or high overall aspect ratio compared to other current industrial methods, such as Printed Circuit Board (PCB) etched coils.

Figure 7 is a view of an electrical component assembly 390 including a wireless charging coil 370. More specifically, wireless charging coil 370 is attached to a ferrite substrate 392 and is associated with a Near Field Communication (NFC) antenna 394 having a contact paddle. The wireless charging coil 370 and NFC antenna 394 can have contact pads (e.g., gold) that connect the wireless charging coil 370 and NFC antenna 394 to circuitry of the mobile device. The assembly includes a first jumper 374, a second jumper 376, and a third jumper 377 that connect respective ends of the coil 370, as explained in more detail above. There can be a film (e.g., clear plastic) on the wireless charging coil 370 and the NFC antenna 394 with the jumpers 374, 376, 377 through the film at the top of the film and only at the connection points. This prevents inadvertently shorting any electrical connections of the coil 370. Alternatively, the jumpers 374, 376, 377 can be insulated such that no film is required. To minimize spacing, the wireless charging coil 370 is within the NFC antenna 394 with the jumpers 376, 377 extending outside of the NFC antenna 394. However, the NFC antenna 394 and the jumpers 376, 377 can be placed at any location relative to the NFC antenna 394.

The overall thickness of the assembly can vary depending on various possible needs and requirements. For example, for a total wireless charging coil thickness of about 0.36mm, the jumper can be 0.05-0.08mm thick, the film can be 0.03mm thick, the NFC antenna 394 and coil 370 can be 0.08mm thick, and the ferrite 392 can be 0.2mm thick.

Fig. 8 is a schematic diagram of an assembled wireless charging coil 470 with a planar two-wire coil. As discussed above, wireless charging coil 470 includes first coil 430 (e.g., a trace) and second coil 450 (e.g., a trace). The assembled coil 470 is manufactured and operated in the manner discussed above with reference to fig. 1-7. The first coil 430 and the second coil 450 can have any desired thickness in order to meet different power requirements. The first coil 430 and the second coil 450 can be connected in series or in parallel.

The width of first coil 430 and/or second coil 450 can be varied along the length of the coil to optimize performance of the assembled wireless charging coil 470. Similarly, the thickness of the first coil 430 and the second coil 450 can vary with the length of the coils. For example, the width (and/or thickness) of the first coil 430 can gradually increase (or narrow) from the first end 434 toward the middle of the first coil 430, and the width (and/or thickness) can similarly gradually narrow (or increase) from the middle of the coil 430 to the second end 436 (e.g., a wide-narrow-wide spiral coil), thereby changing the cross-sectional area therethrough. Any variation in width (e.g., cross-section) or thickness can be used, and/or these dimensions can be maintained constant across portions of the coil, depending on the desired performance characteristics.

Additionally (or alternatively), the spacing between the windings of the coil can be varied to optimize the performance of wireless charging coil 470. For example, the gap width between the traces can widen toward the outside of the first coil 430 and narrow toward the inside of the first coil 430 (or vice versa). Similarly, the distance between first coil 430 and second coil 450 in assembled coil 470 can also be varied to optimize performance. In addition, the geometry of the edges of the coils can be altered (e.g., scalloped, castellated, etc.) to reduce eddy currents.

Figure 9 is a cross-sectional view of a portion of the wireless charging coil of figure 8. The first coil 430 includes a cross section 414 and 424 and the second coil 450 includes a cross section 402 and 412. As shown, the cross-section of the first coil 430 gradually widens and then narrows from the first end to the second end of the first coil 430. As a result, sections 414 and 424 are narrowest (e.g., 0.025 inch), followed by sections 404 and 422 (e.g., 0.030 inch), and sections 418 and 420 are widest (e.g., 0.035 inch). In the same manner, the cross-section of the second coil 450 gradually widens and then narrows from the first end to the second end of the second coil 450. As a result, sections 402 and 412 are the narrowest, and sections 406 and 408 are the widest. The variation in the size of the cross-section of the antenna can be similarly varied in other ways.

Fig. 10 is a schematic diagram of an assembled wireless charging coil 570 with stacked two-wire coils. As discussed above, wireless charging coil 570 includes first coil 530 and second coil 550. Assembled coil 570 is manufactured and operated in the manner discussed above with reference to fig. 1-7 and in the manner discussed in fig. 8-9, except that first coil 530 and second coil 550 are stacked rather than planar. The first coil 530 includes a first end 534 and a second end 536, and the second coil 550 includes a first end 554 and a second end 556. In addition, varying the skew or offset (e.g., stacking distance) of first coil 530 relative to second coil 550 can affect the performance of wireless charging coil 570. The first coil 530 and the second coil 550 can be connected in series or in parallel.

Figure 11 is a cross-sectional view of a portion of the wireless charging coil of figure 10. The coil 570 is similar to the coil of fig. 8-9, including a first coil 530 having sections 514-524 and a second coil 550 having sections 502-512, except that the first coil 530 and the second coil 550 are stacked rather than planar.

Fig. 12 to 13 are views showing the electrical component assembly 690. More specifically, fig. 12 is a perspective view of electrical component assembly 690. The electrical component assembly 690 includes a ferrite shield 692, a Pressure Sensitive Adhesive (PSA) layer 602 positioned on the ferrite shield 692, an assembled coil 670 (e.g., a bifilar coil) positioned therebetween, and jumpers 674, 676 positioned on the PSA layer 602.

Fig. 13 is an exploded view of the electrical component assembly 690 of fig. 12. Bifilar coil 670 includes a first coil 630 having an inner end 634 and an outer end 636 interconnected with a second coil 650 having an inner end 654 and an outer end 656. For ease of use and assembly, the inner and outer ends are on the same side of the assembled coil 670 (e.g., distance minimized to electrically connect the ends).

The ferrite shield 692 includes a first aperture 696 and a second aperture 698 positioned in relation to the placement of the inner end 634 of the first coil 630 and the inner end 654 of the second coil 650 (e.g., when the coil 670 is placed on the ferrite shield 692). Although the apertures 696, 698 are shown as circular, any shape and size opening (e.g., a rectangular opening, etc.) can be used. These holes 696, 698 facilitate assembly and welding of the electrical component assembly 690.

The PSA layer 602 and the ferrite shield 692 are similar in size to each other, and although shown as rectangular, both can have any shape (e.g., circular). The PSA layer fixes the relative placement of the assembled coil 670 and ferrite shield 692. The PSA layer 602 can have adhesive on one or both sides, and can include a polyethylene terephthalate (PET) film region 604 independent of the adhesive on one or both sides. The PET film region 604 facilitates assembly and soldering of the electrical component assembly 690.

The PSA layer 602 includes first and second apertures 606, 608 in the PET film region 604, which are positioned in relation to the placement of the inner ends 634, 654 of the first and second coils 630, 650 (and the first and second apertures 696, 698 of the ferrite substrate 692). Although the apertures 606, 608 are shown as circular, any shape and size opening (e.g., a rectangular opening) can be used. The holes 606, 608 provide access through the PSA layer 602 to electrically connect the jumpers 674, 676 with the inner ends 634, 654 of the assembled coil 670. The PET film region 604 facilitates attachment of the jumpers 674, 676 to the assembly 690.

Fig. 14 is a perspective view of the resonance coil 730. The resonant coil 730 can be a generally rectangular planar spiral trace 731, although the trace 731 can form any suitable shape. The resonance coil 730 includes an inner end 734 and an outer end 736. Traces 731 are stamped on a metal strip or sheet (e.g., copper, aluminum, etc.). The dimensions of the coil 730 can vary depending on the application of the coil 730. The coil 730 can have any suitable thickness and have any suitable overall dimensions. Trace 731 can also have any suitable size. The dimensions can vary depending on physical and performance requirements. The coil 730 can be made of any suitable material for wireless power transfer (e.g., copper alloy, aluminum alloy, tempered copper alloy (e.g., C110), etc.). Due to performance requirements, the gap between the windings of trace 731 is larger for resonant coils than for other types of inductive coils.

Stamping provides a scalable process for high volume production with high throughput. The stamped trace 731 is not easily unwound and can allow for thicker traces. This is advantageous compared to other prior art. For example, it is difficult to wind a coil (e.g., copper) into a specific pattern on a surface, and the wire can be unwound. In addition, etching copper is expensive and can be limited to a maximum thickness (e.g., 0.004 inches thick).

Trace 731 of resonant coil 730 includes a first side 737 and a second side 739 offset from first side 737 by an angular portion 741 of trace 731. The angular portions 741 are aligned with each other (e.g., along line B-B) and are angled in the same direction. In other words, the angled portions 741 are all angled toward a particular side of the coil 730 (e.g., a side toward line a-a) such that a first portion 737 (e.g., an upper portion) of the coil 730 is displaced relative to a second portion 739 (e.g., a lower portion) of the coil 730.

Fig. 15 is a perspective view of a resonant coil assembly 790 including a first resonant coil 730 from fig. 14. The resonance coil assembly 790 includes a first coil 730 and a second coil 750, which are identical to each other (which minimizes manufacturing costs). The resonant coil assembly 790 can be laminated such that the first coil 730 and the second coil 750 are laminated to the membrane 702 (e.g., a PET membrane), for example, by an adhesive (e.g., heat activated, pressure sensitive, etc.) to provide more stability in downstream operations. The first coil 730 can be bonded to one side of the membrane 702 and the second coil 750 can be bonded to the opposite side of the membrane 702.

First coil 730 includes an outer end 736 and an inner end 734, and second coil 750 includes an outer end 756 and an inner end 754. The first coil 730 and the second coil 750 can have coils of exactly the same size and shape, except that the second coil 750 is rotated 180 degrees around the wire D-D. In this way, trace 731 of first coil 730 is positioned between the gaps formed by the windings of trace 751 of second coil 750 (and vice versa), except at the angular portion of each coil along line D-D, where the traces cross each other. The inner end 734 of the first coil 730 can be adjacent to (and electrically connected with) the inner end 754 of the second coil 750, and the outer end 736 of the first coil 730 can be adjacent to the outer end 756 of the second coil 750.

Fig. 16-18 are views of a stamped resonant coil 870. Fig. 16 is a perspective view of a folded stamped resonant coil 870. Coil 870 includes a connector piece 871, a first set of traces 831 of a first coil portion 830 having ends connected to an edge of connector piece 871 at connection point 873, and a second set of traces 851 of a second coil portion 850 having ends connected to the same edge of connector piece 871 at connection point 873. To create the stamped resonant coil 870, a (single) piece of metal is stamped to form the first set of traces 831 and the second set of traces 851 (e.g., such that the arcs of each of the first set of traces 831 and the second set of traces 851 are oriented in the same direction). Each end of the first and second sets of traces 831 and 851 are then connected to the same edge of the connector piece 871 (e.g., an insulating material). The connector sheet 871 facilitates the wiring of the respective sets of traces 831, 851 to each other and the connection of the stamped resonant coil 870 to an electronic circuit. The ends of the first and second sets of traces 831 and 851 are then wired to each other, for example, by using a series of jumpers and/or traces. For example, jumpers and/or traces can be in the connector piece 871 and can extend parallel to the connector piece (and perpendicular to the first and second sets of traces 831 and 851).

Fig. 17 is a partially opened perspective view of the coil 870 of fig. 16. As shown, the first set 831 of traces of the first coil portion 830 is bent at the connection point 873. Fig. 18 is a fully open perspective view of the coil 870 of fig. 16. As shown, the first set 831 of traces of the first coil portion 830 continues to be bent at the connection point 873 until the first coil portion 830 is planar with respect to the second coil portion 850. Bending of the traces can lead to fractures on their outer surfaces, in which case ultrasonic welding can be used to ensure electrical connectivity. Alternatively, the first and second sets of traces 831 and 851 can be connected to opposite edges of the connector sheet 871 such that bending can be eliminated. Stamping (and bending) in this way reduces the amount of scrap generated, thereby increasing material utilization.

Figure 19 is an exploded view of the low profile electrical component assembly 990. More specifically, the low-profile electrical component assembly 990 includes a substrate 992 (e.g., a PET layer), a layer of filler material 933 (e.g., rubber, foam, durometer, etc.), a coil 930 (e.g., a resonant coil), and a protective layer 902. The protective layer 902 can be partially translucent and can include a tab (tab) (e.g., for application or removal).

Fig. 20 is a perspective view of the filling material 933 of fig. 19. The filling material 933 includes grooves 935 that correspond in size and shape to the size and shape of the coil 930. In this way, the coil 930 is embedded in the filler material 933, which protects the coil shape from bending and/or deformation. Such an assembly facilitates handling of the coil 930 for subsequent operations.

Figure 21 is a schematic diagram illustrating process steps 1000 for manufacturing a wireless charging coil with an adhesive (e.g., glue). In step 1002, a metal sheet is stamped to form a first coil with tie bars. In step 1004, a metal sheet is stamped to form a second coil with tie bars. In step 1006, a first coil is applied to a first laminate (e.g., plastic substrate, Transilwrap) having an adhesive bonded thereto. In step 1008, a second coil is applied to a second laminate (e.g., plastic substrate, Transilwrap) having an adhesive bonded thereto. In step 1010, the first coil is stamped to remove the tie bars. In step 1012, the second coil is stamped to remove the tie bars. Thus, the first coil and the second coil are fixed in place as a result of the adhesive layer on the plastic laminate. In step 1014, a first coil having a laminate bonded thereto is assembled with a second coil having a laminate bonded thereto. More specifically, as discussed above, the first coil having the spiral trace is fitted into the space formed between the traces of the second coil, and conversely, the second coil is fitted into the space formed between the traces of the first coil, thereby forming an assembled coil. As a result, the assembled coil is positioned (e.g., sandwiched) between the first laminate and the second laminate.

In step 1016, a heat press is applied to the assembled coil to displace and dispose the adhesive layer from the first and second laminates. More specifically, the heat applied should be hot enough to melt the adhesive (e.g., in excess of 220-. The applied pressure pushes the first coil towards the second laminate sheet such that the adhesive of the second laminate sheet positioned between the traces of the second coil is displaced and forced between the spacing between the first trace of the first coil and the second trace of the second coil. Pressing the first and second coils together (e.g., with heat and/or pressure) migrates the adhesive into the spaces between the traces (e.g., to insulate them from one another). This covers or coats the traces of the first and second coils and bonds the first coil to the second coil. The pressure, heat, and duration can vary depending on the desired cycle time for manufacturing the assembled coil. It is noted that such a process can result in the planes of the first and second coils being offset when assembled together.

Fig. 22 is a partial cross-sectional view of the first stamped coil 1130 as applied to the first laminate 1123. The first laminate 1123 includes an adhesive layer 1127 applied to a surface thereof. When the first stamped coil 1130 is applied to the first laminate 1123, some of the adhesive 1127 is displaced to each side such that the displaced adhesive 1127 accumulates against each side of the traces 1131 of the first laminate 1123. Thus, the adhesive 1127 on each side and under the traces 1131 of the first stamped coil 1130 prevents the traces 1131 from moving relative to the first laminate 1123.

Fig. 23 is a partial cross-sectional view of an assembled coil positioned between a first laminate 1123 and a second laminate 1125. As described above, when assembled, the first coil 1130 having the first trace 1131 is fitted into the space formed between the second traces 1151 of the second coil 1150, and conversely, the second coil 1150 is fitted into the space formed between the first traces 1131 of the first coil 1130, thereby forming the assembled coil 1170. As a result, the assembled coil 1170 is positioned (e.g., sandwiched) between the first laminate 1123 and the second laminate 1125. This displaces the first adhesive 1127 between the first traces 1131 of the first coil 1130 and displaces the second adhesive 1129 between the second traces 1151 of the second coil 1150.

When the first adhesive 1127 and the second adhesive 1129 are disposed (e.g., by pressure and/or heat), the adhesive covers the surfaces of the traces 1131, 1151 (e.g., by melting) and acts as an insulator and stabilizing means for the traces 1131, 1151. In other words, the first coil 1130 and the second coil 1150 are combined together. This prevents relative movement of the traces 1131, 1151, which prevents the first stamped coil 1130 from contacting the second stamped coil 1150 and shorting the assembled coil 1170. As an example, for a total thickness of 0.0225 inches, the first stamped coil 1130 and the second stamped coil 1150 can each be 0.0125 inches thick, and each adhesive layer 1127, 1129 can be 0.0055 inches thick. The total thickness can be 0.0205 inches with a total bond movement of 0.002 inches after pressure and/or heat has been applied.

Fig. 24-25 are partial views of an assembled coil 1170. More specifically, fig. 24 is a partial cross-sectional view of an assembled coil 1170, and fig. 25 is a partial top view of the assembled coil 1170 of fig. 24. As described in detail above, the first stamped coil 1030 includes a planar spiral trace 1031 that spirals to form an inner portion 1032 at the center of the coil 1030. The assembled coil 1170 includes (as discussed above) a first coil having spiral traces 1131 that fit into the space formed between the traces 1151 of the second coil 1150, and conversely, the second coil 1150 fits into the space formed between the traces 1131 of the first coil 1130. Thus, the first and second coils 1130, 1150 form a parallel planar spiral.

As discussed above, a first laminate 1123 (e.g., a transferwrap) having a first adhesive layer is applied to a first stamped coil 1130, and a second laminate 1125 (e.g., a transferwrap) having a second adhesive layer is applied to a second stamped coil 1150. As a result, the first and second stamped coils 1130, 1150 are positioned between the first and second laminates 1123, 1125. When the first and second coils 1130, 1150 are assembled with each other, the adhesive 1127 (colored black for clarity) is displaced to fill the space between the first and second traces 1131, 1151.

Fig. 25 illustrates displacement of the adhesive 1127 when the first and second coils 1130, 1150 are assembled. More specifically, an adhesive 1127 (colored black for clarity) is shown between the first and second traces 1131, 1151. Additionally, in the particular example shown, more pressure has been applied on the left first and second traces 1131a, 1151a than on the right traces 1131b, 1151 b. As a result, less adhesive 1127 has been displaced on the right side than on the left side, thereby making the right side trace 1151b less visible than the left side trace 1151a (due to the black colored adhesive 1127).

Fig. 26 is a top view of an assembled coil 1270 of the present disclosure. As discussed above, the assembled coil 1270 includes: a first coil 1030 having a first spiral trace 1031, the first spiral trace 1031 having an inner end 1034 and an outer end 1036; a second coil 1050 having a second spiral trace 1051, the second spiral trace 1051 having an inner end 1054 and an outer end 1056; a first jumper 1277 attached to the outer end 1236 of the first coil 1230; a second jumper 1274 attached to the inner end 1234 of the first coil 1230 and the outer end 1256 of the second coil 1250; and a third jumper 1276 attached to the inner end 1254 of the second coil 1250. The first spiral coil 1030 and the second spiral coil 1050 form an inner portion 1272.

A laminate 1227 (e.g., a film, an adhesive film, a plastic film, etc.) covers the assembled coil 1270 including the inner portion 1272. As explained above, the adhesive layer of the laminate 1227 stabilizes and insulates the first coil 1230 and the second coil 1250. This prevents relative movement of the first and second coils 1230 and 1250 and prevents the first and second coils 1230 and 1250 from accidentally contacting each other and shorting the assembled coil 1270.

The laminate 1227 can define one or more openings (cutouts). More specifically, the laminate 1227 can define an interior opening 1223 to provide access to (e.g., expose) the first interior end 1234 of the first coil 1230 and the second interior end 1254 of the second coil 1250. The laminate 1227 can also define an exterior aperture 1225 to provide access to (e.g., expose) the first exterior end 1236 of the first coil 1230 and the second exterior end 1256 of the second coil 1250. The first aperture 1223 can extend to substantially the inner portion 1272. The assembled coil 1270 (and its first and second coils 1230, 1250) can be any material and/or pattern (e.g., a6 pattern coil).

For any of the embodiments discussed above, the wireless charging coil (e.g., dual coil) can be configured and then the first and second coils of the wireless charging coil (e.g., at different locations and/or times), whether stacked or planar, can be electrically connected to each other in series or in parallel depending on electrical requirements.

Having described the systems and methods in detail, it is to be understood that the foregoing description is not intended to limit the spirit and scope thereof. It is to be understood that the embodiments of the present disclosure described herein are merely exemplary, and that those skilled in the art may make any variations and modifications without departing from the spirit and scope of the present disclosure. All such variations and modifications, including those discussed above, are intended to be included within the scope of the present disclosure.

Claims (19)

1. A wireless charging coil, comprising:

a first stamped coil having a first spiral trace defining a first pitch between windings; and

a second stamped coil having a second spiral trace defining a second pitch between windings,

the first stamped coil and the second stamped coil being in a coplanar relationship, the first stamped coil being positioned within the second pitch of the second stamped coil and the second stamped coil being positioned within the first pitch of the first stamped coil, the first and second coils being electrically connected; and

an adhesive covering and surrounding the first stamped coil and the second stamped coil to bond the coils together and insulate the coils.

2. The wireless charging coil of claim 1, further comprising a first laminate and a second laminate, wherein the first stamped coil and the second stamped coil are positioned between the first laminate and the second laminate.

3. The wireless charging coil of claim 1, wherein the first stamped coil and the second stamped coil are connected in series.

4. The wireless charging coil of claim 1, wherein the first stamped coil and the second stamped coil are connected in parallel.

5. The wireless charging coil of claim 1, wherein the first stamped coil comprises an inner end and an outer end, the inner end disposed on the same side of the first stamped coil as the outer end.

6. The wireless charging coil of claim 5, further comprising a first jumper attached to the outer end of the first coil.

7. The wireless charging coil of claim 6, wherein the second stamped coil comprises an inside end and an outside end, and further comprising a second jumper attached to the inside end of the first coil and the outside end of the second coil.

8. The wireless charging coil of claim 7, further comprising a third jumper attached to the inside end of the second coil.

9. A method of making a wireless charging coil, comprising:

stamping a metal sheet to form a first coil having a first spiral trace defining a first pitch between windings;

applying a first stamped coil to the first laminate via the adhesive of the first laminate;

stamping the sheet metal to form a second coil having a second spiral trace defining a second pitch between the windings;

applying a second stamped coil to the second laminate via the adhesive of the second laminate;

inserting the first stamped coil and the second stamped coil to form a planar coil assembly having a first stamped coil and a second stamped coil, wherein the first stamped coil is positioned within the second pitch of the second stamped coil and the second stamped coil is positioned within the first pitch of the first stamped coil and the second stamped coil are positioned between the first laminate sheet and the second laminate sheet;

heating and pressing the planar coil assembly to displace the adhesive of the first and second laminates and to dispose the adhesive of the first and second laminates around and bond the first and second coils together.

10. The method of claim 9, wherein the heat applied by the hot press melts the adhesive but does not melt the laminate.

11. The method of claim 10, wherein the pressure applied by the heat press displaces and compresses the adhesive between the first trace of the first coil and the second trace of the second coil to insulate the coils.

12. The method of claim 9, wherein stamping the metal sheet forms the first coil with tie bars.

13. The method of claim 12, further comprising stamping the first coil to remove the tie bar.

14. The method of claim 9, wherein the first stamped coil and the second stamped coil are connected in series.

15. The method of claim 9, wherein the first stamped coil and the second stamped coil are connected in parallel.

16. The wireless charging coil of claim 9, wherein the first stamped coil comprises an inner end and an outer end, the inner end disposed on the same side of the first stamped coil as the outer end.

17. The wireless charging coil of claim 16, further comprising a first jumper attached to the outer end of the first coil.

18. The wireless charging coil of claim 17, wherein the second stamped coil comprises an inside end and an outside end, and further comprising a second jumper attached to the inside end of the first coil and the outside end of the second coil.

19. The wireless charging coil of claim 18, further comprising a third jumper attached to the inside end of the second coil.