Patent Publication Number: US-2023150383-A1

Title: Metamaterial panel for enhancing wireless charging of electric vehicles

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to wireless charging and, more particularly, to wireless charging of electric vehicles. 
     BACKGROUND 
     Electric vehicles (EVs) can be wirelessly charged automatically without the use of electric cables. Particularly, an inductive wireless power transfer system (WPTS) with a transmitter coil located proximate or near an EV (e.g., buried in pavement or in a transmitter pad on the pavement) generates an alternating electromagnetic field that intersects a receiver coil of the EV. Intersection of the alternating electromagnetic field with the receiver coil creates an alternating current in the receiver coil and a power converter (e.g., a rectifier) draws the alternating current from the receiver coil and converts the alternating current to direct current that charges a battery of the EV. 
     Inductive WPTSs transmit more power than other (e.g., capacitive) WPTSs due at least in part to relatively higher energy densities of the alternating electromagnetic field in free space. However, if the space or gap between the transmitter coil and the receiver coil is greater than a desired distance, efficiency of a wireless charge is reduced. In addition, different sizes and/or shapes between transmitter coils and receiver coils can result in reduced wireless charging efficiency. 
     The present disclosure addresses the issues of wireless charging efficiency during wireless charging of EVs, among other issues related to wireless charging of EVs. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     In one form of the present disclosure, a panel for wireless charging of an electric vehicle includes a metamaterial panel with a first shape and a second shape different than the first shape. The metamaterial panel is configured to be positioned between a transmitter coil of a wireless power transfer station and a receiver coil of the electric vehicle during wireless charging of the electric vehicle and change between the first shape and the second shape as a function of at least one of a size of the transmitter coil, a size of the receiver coil, and a distance between the transmitter coil and the receiver coil. 
     In another form of the present disclosure, a panel for wireless charging an electric vehicle includes a metamaterial panel configured to change shape from a first shape to a second shape different than the first shape, and from the second shape and the first shape. A robot including a robotic arm and/or a robotic vehicle is included and the metamaterial panel is coupled to the robot. The robot is configured to position the metamaterial panel between a transmitter coil of a charging station and a receiver coil of the electric vehicle during wireless charging of the electric vehicle. 
     In still another form of the present disclosure, a panel for wireless charging an electric vehicle includes a metamaterial panel configured to change shape from a first shape to a second shape different than the first shape, and from the second shape and the first shape, and a robot with a control system. The robot includes at least one of a robotic arm and a robotic vehicle, and the metamaterial panel is coupled to the robot. The controller is configured to command the metamaterial panel to change shape and configured to command the robot to position the metamaterial panel between a transmitter coil of a charging station and a receiver coil of the electric vehicle during wireless charging of the electric vehicle. 
     Further areas of applicability and various methods of enhancing the above coupling technology will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present teachings will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG.  1 A  is a front view of an electric vertical takeoff and landing (eVTOL) vehicle approaching a wireless charging station; 
         FIG.  1 B  is a front view of the eVTOL vehicle in  FIG.  1 A  during wirelessly charging of the eVTOL vehicle; 
         FIG.  2    is a front view of the eVTOL vehicle in  FIG.  1 B  with a metamaterial panel in a first shape between a transmitter coil of an inductive WPTS and a receiver coil of the eVTOL vehicle according to the teachings of the present disclosure; 
         FIG.  3 A  is an isolated front view of the metamaterial panel in  FIG.  2   ; 
         FIG.  3 B  is a top view of the metamaterial panel in  FIG.  3 A ; 
         FIG.  3 C  is a side view of the metamaterial panel in  FIG.  3 A  in a non-planar configuration (shape); 
         FIG.  4    is a front view of the eVTOL in  FIG.  1 A  with the metamaterial panel in  FIG.  2    in a second shape between the transmitter coil of the inductive WPTS and the receiver coil of the eVTOL vehicle according to the teachings of the present disclosure; 
         FIG.  5    is a front view of another eVTOL vehicle with the metamaterial panel in  FIG.  2    in a third shape between the transmitter coil of the inductive WPTS and a receiver coil of the eVTOL vehicle according to the teachings of the present disclosure; 
         FIG.  6    is a front view of the eVTOL in  FIG.  1 A  with the metamaterial panel in  FIG.  2    in a fourth shape between another transmitter coil of the inductive WPTS and the receiver coil of the eVTOL vehicle according to the teachings of the present disclosure; 
         FIG.  7    is a perspective view of a robotic vehicle with the metamaterial panel in  FIGS.  3 A- 3 C  according to the teachings of the present disclosure; 
         FIG.  8    is a perspective view of the robotic vehicle in  FIG.  7    positioned between a transmitter coil of an inductive WPTS and a receiver coil of an eVTOL vehicle according to the teachings of the present disclosure; 
         FIG.  9    is a perspective view of the robotic vehicle in  FIG.  7    between a transmitter coil of an inductive WPTS and a receiver coil of another eVTOL vehicle according to the teachings of the present disclosure; 
         FIG.  10    is a front view of the eVTOL vehicle in  FIG.  1 A  approaching an inductive WPTS with a robotic arm coupled to the metamaterial panel in  FIGS.  3 A- 3 C  according to the teachings of the present disclosure; 
         FIG.  11    is a front view of the eVTOL vehicle in  FIG.  1 A  approaching an inductive WPTS with a robotic arm coupled to the metamaterial panel in  FIGS.  3 A- 3 C  according to the teachings of the present disclosure; and 
         FIG.  12    is a front view of an electric vehicle with the metamaterial panel in  FIGS.  3 A- 3 C  between a transmitter coil of an inductive WPTS and a receiver coil of the electric vehicle according to the teachings of the present disclosure. 
     
    
    
     It should be noted that the figures set forth herein are intended to exemplify the general characteristics of the methods, algorithms, and devices among those of the present technology, for the purpose of the description of certain aspects. These figures may not precisely reflect the characteristics of any given aspect, and are not necessarily intended to define or limit specific embodiments within the scope of this technology. Further, certain aspects may incorporate features from a combination of figures. 
     DETAILED DESCRIPTION 
     The present disclosure generally relates to metamaterial panels that focus alternating electromagnetic fields to increase wireless charging efficiency and decrease electromagnetic field leakage during wireless charging of EVs (e.g., eVTOLs electric automobiles, and electric trucks, among others). The metamaterial panels can have more than one shape such that changes in distance between a transmitter coil of a wireless charging station and a receiver coil of the EV, and different shapes and/or sizes between transmitter coils and receiver coils are compensated for during wireless charging of EVs. In some variations of the present disclosure, a robotic vehicle and/or a robotic arm moves and positions one or more metamaterial panels between the transmitter coil of the wireless charging station and the receiver coil of an EV. 
     Referring to  FIGS.  1 A and  1 B , a front view of an eVTOL vehicle  10  approaching an inductive WPTS  20  is shown in  FIG.  1 A  and wireless charging of the eVTOL vehicle  10  at the inductive WPTS  20  is shown in  FIG.  1 A . The eVTOL vehicle  10  vehicle incudes a battery  12  and a receiver coil  14 , and the inductive WPTS  20  includes a charging station  22  with a transmitter coil  24 , a power source  26 , a processor  28 , and at least one sensor  29 . The receiver coil  14  is positioned a distance ‘h 1 ’ from the transmitter coil  24  during wireless charging and the transmitter coil  24  generates an alternating electromagnetic field  25  that intersects the receiver coil  14 . It should be understood that the eVTOL vehicle  10  can hover at the distance h 1  during wireless charging, or in the alternative, the eVTOL vehicle  10  can land and be supported on the inductive WPTS  20  (or some structure associate with the inductive WPTS  20 ) with the distance h 1  being between the receiver coil  14  and the transmitter coil  24  during wireless charging. However, and due at least in part to the distance h 1  between the receiver coil  14  and the transmitter coil  24 , fluctuations of the distance h 1  during wireless charging, the shape and size of the receiver coil  14 , and/or the shape and size of the transmitter coil  24 , only a portion of the alternating electromagnetic field  25  intersects the receiver coil  14 . In some variations, the at least one sensor  29  includes a distance or proximity sensor  29  configured to detect or determine a distance between the receiver coil  14  and the transmitter coil  24 . And in such variations the proximity sensor  29  can provide a signal to the processor  28  and the processor  28  can initiate wireless charging of the eVTOL vehicle  10  when the receiver coil  14  is at the distance h 1  from the transmitter coil  24 . 
     Referring now to  FIG.  2   , wireless charging of the eVTOL vehicle  10  using a metamaterial panel  100  according to the teachings of the present disclosure is shown. The metamaterial panel  100  is positioned between the receiver coil  14  of the eVTOL vehicle  10  and the transmitter coil  24  of the inductive WPTS  20  and, as illustrated in  FIG.  2   , the metamaterial panel  100  focuses the alternating electromagnetic field  25  onto the receiver coil  14 . That is, the metamaterial panel  100  “bends” the alternating electromagnetic field  25  such that more of the alternating electromagnetic field  25  intersects the receiver coil  14  when compared to the metamaterial panel  100  not being present or used ( FIG.  1 A ). Accordingly, the metamaterial panel  100  focuses the alternating electromagnetic field  25  onto the receiver coil  14  such that the efficiency of wireless charging the eVTOL vehicle  10  is enhanced (increases) and electromagnetic field leakage is decreased compared to when the metamaterial panel  100  is not present or used. 
     As used herein, the term “metamaterial panel” refers to at least one layer of a negative-index metamaterial configured to bend or focus an outgoing electromagnetic field from a transmitter coil that is diverging from a transverse axis of the transmitter coil (e.g., transverse axis ‘A’ of transmitter coil  24  in  FIG.  1 B ) back towards the transverse axis (e.g., see electromagnetic field  25  in  FIG.  2   ). And in some variations the metamaterial panel(s) disclosed herein is a printed circuit board (PCB) metamaterial panel with a metamaterial layer on one or both sides of a circuit board substrate. 
     Not being bound by theory, metamaterials and metamaterial panels disclosed herein have a negative reflective index with an artificial periodic index such that the metamaterial has a negative relative permittivity and/or a negative relative permeability, e.g., as disclosed in the publication “Thin PCB-type metamaterials for improved efficiency and reduced EMF leakage in wireless power transfer systems”,  Microwave Theory and Techniques  64.2 (2016): 353-364, by Cho et al., which is incorporated herein in its entirety by reference. In addition, the resonance frequency, the relative permeability, and the thickness of the metamaterial layer(s) are configured to enhance focusing of the alternating electromagnetic field  25  with intermediate frequencies between 1 kHz to 10 MHz. 
     While an eVTOL vehicle  10  is shown in  FIGS.  1 A- 2   , it should be understood that other vehicles, including but not limited to electric motor vehicles (e.g., see  FIG.  12   ), watercraft, an aircraft, a space craft, a golf cart, a motorcycle, and/or any other form of motorized transport are included in the teachings of the present disclosure. In addition, the eVTOL vehicle  10 , and other electric vehicles disclosed herein, can be a battery electric vehicle, a plug-in hybrid electric vehicle, or any other form of electric vehicle. 
     Referring to  FIGS.  3 A- 3 C , isolated views of the metamaterial panel  100  are shown. In some variations the metamaterial panel  100  includes a plurality of metamaterial sub-panels  102  (also referred to herein simply as “sub-panels  102 ”) coupled to each other with a frame  103 . And in at least one variation, the sub-panels  102  are configured to be positioned or orientated at a non-zero angle (θ) relative to each other and a reference plane ‘P’ as shown in  FIG.  3 C . In some variations, angles between one or more of the sub-panels  102  are equal to each other (e.g., θ 1 =θ 2 =θ 3 ), while in other variations angles between one or more of the sub-panels  102  are not equal to each other (e.g., θ 1 ≠θ 2 ≠θ 3 ). In at least one variation, the sub-panels  102  are configured to be positioned or orientated at a non-zero angle (θ) relative to the reference plane P using one or more hinges  104  between adjacent sub-panels  102 , while in other variations the sub-panels  102  are configured to be positioned or orientated at a non-zero angle (θ) relative to the reference plane P without the use of hinges. For example, the frame  103  can include one or more malleable material portions (e.g., malleable polymer portions) that are configured to be formed into a desired shape without breaking or cracking and/or one or more shape memory material portions (e.g., shape memory polymer portions) configured to be formed into a desired shape without breaking or cracking. 
     Referring now to  FIGS.  4 - 6   , non-limiting examples of the metamaterial panel  100  in a non-planar configuration during wireless charging are shown. For example,  FIG.  4    shows the metamaterial panel  100  in a second shape compared to a first shape shown in  FIG.  2   , and the metamaterial panel  100  in the second shape enhances focusing of the alternating electromagnetic field  25  onto the receiver coil  14  of the eVTOL vehicle  10  compared to the metamaterial panel in the first shape. Referring particularly to  FIG.  5   , the metamaterial panel  100  is in a third shape compared to the second shape shown in  FIG.  4    and the third shape has a larger radius of curvature such that the alternating electromagnetic field  25  is focused onto a receiver coil  14   a  of an eVTOL vehicle  10   a  that is larger than the receiver coil  14  of the eVTOL vehicle  10 . That is, the shape of the metamaterial panel  100  is adjusted such that the efficiency of wireless charging the eVTOL vehicles  10 ,  10   a  using the same transmitter coil  24  is enhanced even though receiver coils  14 ,  14   a , have different sizes. And with reference to  FIG.  6   , the metamaterial panel  100  is in a fourth shape that enhances focusing of an alternating electromagnetic field  25   a  generated from a transmitter coil  24   a  that is larger than the transmitter coil  24  shown in  FIGS.  4  and  5   . That is, the shape of the metamaterial panel  100  is adjusted such that the efficiency of wireless charging the eVTOL vehicle  10  is enhanced even though the transmitter coils  24 ,  24   a  have different sizes. 
     Positioning the metamaterial panel  100  between a receiver coil of an EV and a transmitter coil of a WPTS is performed or provided manually, automatically, or a combination thereof. For example, and with reference to  FIG.  7   , in some variations the metamaterial panel  100  is coupled to a vehicle  30  and the metamaterial panel  100  is rolled into a desired position between a transmitter coil of a WPTS and a receiver coil of an electric vehicle. In such variations the vehicle  30  can include one or more wheels  310 , a base  320  for mounting or coupling to the metamaterial panel  100 , and one or more height actuators  330  coupled to the base  320  and configured to move the metamaterial panel in a height direction (z direction). In operation, the vehicle  30  rolls on a surface ‘S’ and positions the metamaterial panel  100  between a transmitter coil of a WPTS and a receiver coil of an electric vehicle. In addition, the one or more height actuators  330  are configured to adjust the height of the metamaterial panel  100  relative to a transmitter coil and receiver coil, and thereby enhance the efficiency of wireless charging a given or particular electric vehicle. 
     In some variations the vehicle  30  includes one or more shape actuators  340  configured to adjust and change the shape of the metamaterial panel  100  as discussed above. And in such variations the one or more shape actuators  340  can be activated manually to change the shape of the metamaterial panel  100  and/or the vehicle  30  can be a robotic vehicle  30  with a control system  350  configured to receive a signal and command the one or more shape actuators  340  to change the shape of the metamaterial panel  100 . A “control system” as used herein includes any device, component, system, element or arrangement or groups thereof that enable information/data to be used to control the robotic vehicle  30  and/or the metamaterial panel  100 . 
     In at least one variation the control system  350  is configured to receive a signal command the one or more shape actuators  340  to change the shape of the metamaterial panel  100  into one of a plurality of different shapes depending on a given electric vehicle to be or being wirelessly charged and/or as a function of the received signal, e.g., from a first shape to a second shape, from a second shape to a third shape, from the third shape back to the first shape, from the first shape to the third shape, from the third shape to the second shape, among others. In addition, in some variations the control system  350  is configured to command a motor (not shown) of the robotic vehicle  30  in response to receiving a signal such that the robotic vehicle  30  rolls across the surface S into a desired position between a transmitter coil of a WPTS and a receiver coil of an electric vehicle. 
     It should be understood that the components of the vehicle  30  (i.e., the wheels  310 , base  320 , actuators  330  and/or  340 , and control system  350 ) are either transparent to alternating electromagnetic fields or are shielded from alternating electromagnetic fields. For example, the wheels  310 , base  320 , and actuators  330  and/or  340  can be made from polymer materials and the control system  350  and any electrical components of the robotic vehicle can be shielded with a ferrite material. 
     Referring to  FIG.  8   , the vehicle  30  with the metamaterial panel  100  has rolled into a position between the inductive WPTS  20  and an eVTOL vehicle  10   b  with a battery  12   b  (i.e., a battery pack) and a receiver coil  14   b . The eVTOL vehicle  10   b  is positioned at a distance or height ‘h 2 ’ from the inductive WPTS  20  and the metamaterial panel  100  is in a non-planar configuration such that an alternating electromagnetic field  25  generated from the transmitter coil  24  ( FIG.  5   ) is focused on the receiver coil  14   b.    
     Referring to  FIG.  9   , the vehicle  30  with the metamaterial panel  100  has been rolled into a position between the inductive WPTS  20  and another eVTOL vehicle  10   c  with a battery  12   c  and a receiver coil  14   c . The receiver coil  14   c  is larger in size than the receiver coil  14   b  shown in  FIG.  8    and the receiver coil  14   c  is positioned at a distance or height ‘h 3 ’ (which may or may not be equal to h 2 ) from the transmitter coil  24  ( FIG.  5   ). Also, the metamaterial panel  100  is in a non-planar configuration such that the alternating electromagnetic field  25   b  generated from a transmitter coil (not shown) is focused on the receiver coil  14   c . Accordingly, the vehicle  30  with the metamaterial panel  100  provides enhanced wireless charging efficiency and reduced alternating electromagnetic field leakage between a given WPTS and a plurality of eVTOLs having different shapes and sizes. Also, it should be understood that in variations where the eVTOL vehicles  10   b ,  10   c  are hovering over the inductive WPTS  20 , and the heights h 2 , h 3  vary during wireless charging, the control system  350  can be configured to change the shape of the metamaterial panel  100  such that the alternating electromagnetic field  25  remains desirably focused on the receiver coils  14   b ,  14   c.    
     While  FIGS.  7 - 9    show the metamaterial panel coupled to a vehicle, it should be understood that the metamaterial panel  100  can be coupled to members or other structures that move and position the metamaterial panel  100  into a desired position. For example, and with reference to  FIG.  10   , in some variations the metamaterial panel  100  is couple to an arm  120  that extends from a column or wall  130 . In such variations the arm  120  can rotate about an axis ‘B’ such that the metamaterial panel  100  is rotated to a position between the inductive WPTS  20  and the eVTOL vehicle  10 . In addition, in some variations the arm  120  is configured to move up and down (+/−z direction) in order to adjust the height of the metamaterial panel  100  between the transmitter coil  24  of the inductive WPTS  20  and the receiver coil  14  of the eVTOL vehicle  10 . And referring to  FIG.  11   , in at least one variation the metamaterial panel  100  is couple to an arm  140  that extends from a floor ‘F’. In such variations the arm  140  can rotate about an axis ‘C’ such that the metamaterial panel  100  is rotated to a position between the inductive WPTS  20  and the eVTOL vehicle  10 . In addition, in some variations the arm  140  is configured to move up and down (+/−z direction) in order to adjust the height of the metamaterial panel  100  between the transmitter coil  24  of the inductive WPTS  20  and the receiver coil  14  of the eVTOL vehicle  10 . 
     In some variations the arm  120  and/or the arm  140  is a robotic arm configured to be commanded by a control system  125  ( FIG.  10   ),  145  ( FIG.  11   ) to move the metamaterial panel  100  into a desired position between the transmitter coil  24  of the inductive WPTS  20  and the receiver coil  14  of the eVTOL vehicle  10 . And in such variations the control system  125 ,  145  can be configured to command one or more shape actuators (not shown) to change the shape of the metamaterial panel  100  into one of a plurality of different shapes depending on a given electric vehicle to be or being wirelessly charged. In addition, and while the arms  120 ,  140  are shown holding the metamaterial panel  100  in a horizontal position (i.e., in the x-y plane), in some variations the arm  120  and/or the arm  140  are configured to move and position the metamaterial panel  100  in a vertical position (e.g., the y-z plane). For example, in some variations the inductive WPTS  20  includes a transmitter coil  24  extending along the z-axis (i.e., vertically) shown in  FIGS.  10  and  11    such that eVTOLs with a vertically oriented receiver coil can be wirelessly charged while hovering or stationed horizontal to the vertical transmitter coil  24 . And in such variations, the arms  120 ,  140  hold the metamaterial panel  100  in a vertical orientation between the vertical transmitter coil  24  and a vertically oriented receiver coil of an eVTOL. 
     Referring to  FIG.  12   , wireless charging an EV  10   d , i.e., an electric automobile, using the metamaterial panel  100  is shown. It should be understood that the metamaterial panel  100  is positioned between the transmitter coil  24  of the inductive WPTS  20  and a receiver coil  14   d  of the EV  10   d  such that wireless charging efficiency is enhanced. It should also be understood that the metamaterial panel  100  can be moved and positioned between the transmitter coil  24  and the receiver coil  14   d , and change shape, using the same or similar vehicle, arms, and/or control systems as described above. 
     The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. For example, it should be understood that fins with shapes and sizes different than the fins described above are included within the teachings of the present disclosure. Also, work of the presently named inventors, to the extent it may be described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present technology. 
     The systems, components and/or methods described above can be realized in hardware or a combination of hardware and software and can be realized in a centralized fashion in one processing system or in a distributed fashion where different elements are spread across several interconnected processing systems. Any kind of processing system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software can be a processing system with computer-usable program code that, when being loaded and executed, controls the processing system such that it carries out the methods described herein. The systems, components and/or methods also can be embedded in a computer-readable storage, such as a computer program product or other data programs storage device, readable by a machine, tangibly embodying a program of instructions executable by the machine to perform methods and methods described herein. These elements also can be embedded in an application product which comprises all the features enabling the implementation of the methods described herein and, which when loaded in a processing system, is able to carry out these methods. 
     As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical “or.” It should be understood that the various steps within a method may be executed in different order without altering the principles of the present disclosure; various steps may be performed independently or at the same time unless otherwise noted. Disclosure of ranges includes disclosure of all ranges and subdivided ranges within the entire range. 
     The headings (such as “Background” and “Summary”) and sub-headings used herein are intended only for general organization of topics within the present disclosure, and are not intended to limit the disclosure of the technology or any aspect thereof. The recitation of multiple embodiments having stated features is not intended to exclude other embodiments having additional features, or other embodiments incorporating different combinations of the stated features. 
     As used herein, the terms “comprise” and “include” and their variants are intended to be non-limiting, such that recitation of items in succession or a list is not to the exclusion of other like items that may also be useful in the devices and methods of this technology. Similarly, the terms “can” and “may” and their variants are intended to be non-limiting, such that recitation that an embodiment can or may comprise certain elements or features does not exclude other embodiments of the present technology that do not contain those elements or features. 
     The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the specification and the following claims. Reference herein to one aspect, or various aspects means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment or aspect. The appearances of the phrase “in one aspect” (or variations thereof) are not necessarily referring to the same aspect or embodiment. 
     While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended, are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.