Patent Publication Number: US-2018048247-A1

Title: Electricity Generating Wheel and Mat

Description:
CROSS REFERENCES 
     The present application for patent claims priority to U.S. Provisional Patent Application No. 62/372,775 by Gerstenberger, entitled “Electricity Generating Wheel and Matt,” filed Aug. 9, 2016,” which is expressly incorporated herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     The electret material portion of the invention described herein was made with support of the U.S. Government, and the U.S. Government may have certain rights in the invention as provided for by the terms of Grant No. W31PQ-07-1-003 awarded by the Defense Advanced Research Projects Agency (DARPA). 
    
    
     BACKGROUND 
     The following relates to materials which generate electricity when deformed and a converter circuit for the same. 
     Flexible material may be used to generate electricity from routine motions of individuals (e.g., walking). For example U.S. Pat. No. 6,433,465 uses the electrical response phenomenon of electrostrictive polymers in reverse to harvest or generate electrical power from human walking motion. 
     However alternative apparatuses and methods for recovering quantities of electricity from motion may provide increased efficiency and electricity production. 
     SUMMARY 
     The described features generally relate to methods, systems, devices, or apparatuses for generating electricity from a wheel or a mat. Some embodiments relate to devices laid within a type of mat or flooring, roads, sidewalks and paths and within the tires of automobiles and other wheeled vehicles which generate electricity from the movement and pressing of those tires and of people, machinery and other things pressing on the ground, flooring, grass and roadwork of any kind. 
     An embodiment may comprise a DC to DC converter circuit. The circuit may include a voltage input terminal and a voltage output terminal together with a first capacitor element and a second capacitor element, where the second capacitor element comprises a plurality of individual capacitors. The circuit may further include a switch network which has a first phase wherein the plurality of capacitors are in series and connected to the first capacitor element and disconnected from the output terminal and a second phase wherein the plurality of capacitors are in parallel and connected to the output terminal and disconnected from the first capacitor element. Finally, there may be a switch controller that controls the switching between the phases. The switch controller monitors the voltage on the first terminal. The switching may be initiated only if the voltage in the first terminal is sufficiently high. 
     Another embodiment may comprise a DC generation device and storage device. The device may include a power generation section comprising multiple layers of an electret film. A rectifier may be connected to the electret film, which in turn may be connected to a DC to DC converter, for example the converter described immediately above. Finally, a power storage device (e.g., battery or capacitor) may be connected to the converter. 
     Another embodiment may include transferring gathered electricity to the battery system by means of a wireless charging system encompassed both inside and outside a tire. 
     Another embodiment may be the use of various configurations of the electret material inside of a tire or wheel along with other additions to the superstructure of the wheel or tire so that electricity can be collected and transferred. 
     Another embodiment may be the use of various configurations of the electret material inside, on top or underneath a mat of multiple sorts that can then generate and collect electricity from movement above or below the mat. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example of a power generating mat in accordance with aspects of the present disclosure. 
         FIG. 2  illustrates an example of a power generating tire in accordance with aspects of the present disclosure. 
         FIGS. 3A and 3B  illustrate an example of an electret film in accordance with aspects of the present disclosure. 
         FIG. 4  illustrates an example of power generation from a tire or mat in accordance with aspects of the present disclosure. 
         FIG. 5  illustrates an example of a schematic representation of a electret film in accordance with aspects of the present disclosure. 
         FIG. 6  illustrates an example of a circuit in accordance with aspects of the present disclosure. 
         FIG. 7  illustrates an example of a circuit in accordance with aspects of the present disclosure. 
         FIG. 8  illustrates an example of the movement of electricity from a tire to a battery system by means of a wireless charging system in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As used in this specification, the following terms will be defined as follows. 
     “Tire” meaning any form of wheeled conveyance including but not limited to all State authorized vehicles permitted to drive on roads, bicycles, forklifts, tractors, wheeled machinery, etc. 
     “Mat” meaning any form of floor, road or trail covering which could be designed to hold the electret film or other generation device(s) for the purpose of generating electricity or energy by means of pressure either above or below. 
     “Mat” meaning any form of flat surface or any form of floor or road covering which could be designed capable of sandwiching something small between layers including but not limited to a rubber mat, any plastic, asphalt/cement or any amorphous material that can be laid on a road or on a walkway where traffic from walking persons to wheeled conveyances may cross. 
     “Electret film” means a polymer film which has been permanently charged, for example by radiation or corona discharge. In certain embodiments, the film has cavities, cells or voids and the cell walls have been charged after formation of the cavities. In one embodiment, the polymer film is polypropylene, but a great number of different polymers may be used, including but not limited to polyethylene, polytetrafluoroethylene, PVDF, polymethylpentene and cyclic olefin copolymer. In another example, the film is a foam layer having positive and negative charges on opposite internal void surfaces and at least one conductive coating on an outer surface of the layer. Some films may have conductive layers on both outer surfaces while other films may have no conductive layer. In certain embodiments, the cavity, cell, or void sizes will range between 1 μm and 1 mm or any range therein. Non-limiting examples of film thickness may be about 25 μm to about 1 mm or any range in between. Non-limiting examples of such electret films are found in U.S. Pat. Nos. 4,654,546, 6,852,402 and 7,376,239. 
     “Power storage device” means any existing or future developed device capable of storing electrical or other forms of energy including but not limited to batteries, capacitors or supercapacitors. 
     “Wireless Charging System” means current or future forms of wireless energy power transfer device capable of moving energy without the use of wires or other direct connections from the charging device or storage therein to other power storage devices. 
       FIG. 1  illustrates an example of a power generating mat  100  in accordance with aspects of the present disclosure. Mat  100  may include one or more layers of electret film  105  as described herein running both vertically and horizontally inside or outside the two or more layers of the mat as described to generate electricity. The mat  100  may also include electrical leads  110  for electrically coupling the electret film  105  to other components such as a circuit, an energy storage device, or the like. In some examples, the multiple layers of the of electret film  105  may comprise a piezoelectric material. 
       FIG. 2  illustrates an example of a power generating wheel or tire  200  in accordance with aspects of the present disclosure. Tire  200  may include a group or groupings of electret material  205  as described herein running the length and breadth of the tires contact with the ground or whatever it is riding upon inside of a layer of tire sandwiched with another layer of rubber or like flexible or non-flexible material inside. The electret material  205  may be an example of the electret film  105  described with reference to  FIG. 1 . Although  FIG. 2  illustrates only a single layer around the center of the tire  200 , other embodiments may have more layers side by side and also stacked on top of each other to create more electricity. Likewise there are other ways to place the electret material. 
       FIG. 2  also illustrates an example of a design including rows of rubber plates  210  raised from the inside floor of the tire  200  an amount of ½ inch or more (or less) with the layer or layers of electret film  205  riding above those plates inside of a “hammock” like structure  215  whereby the optimal amount of pressure may be put into the electret film rolls  205  by pressing against the hammocks containing them using the force of the roadway or other flooring to distend the tire inward creating that force. In some examples, the plates  210  may be rubber press plates and the electret film coils  515  may be rolled or layered. In some examples, the “hammock” like structure  215  may be rubber or another flexible material and the electric film may be rolled or layered. 
       FIG. 3A  illustrates an example of an electret film  300 - a  as disclosed in U.S. Pat. No. 4,654,546. The electret film  300 - a  may include a plastic matrix  305  having voids or blisters  310  and positively or negatively polarized metal films  315  and  320  on an upper and lower surface of the plastic matrix. 
       FIG. 3B  illustrates a schematic representation of an electret film  300 - b  including ferroelectric film  325 . 
       FIG. 4  illustrates an example of how the power generation section  400  for a tire (e.g., tire  200  from  FIG. 2 ) may be formed. As shown in  FIG. 4 , an electret film  405  may be folded and stacked. The electret film  405  may be an example of aspects of electret film  105  described with reference to  FIG. 1  (e.g., similar to FIG. 2A in U.S. Pat. No. 4,654,546). The folds at bends  405  may result in the same polarity metal surfaces being in contact with one another. Electrical leads  410  and  415  may extend within the folds of the film  405  such that electrical leads  415  contact only one side (i.e., one metal surface layer) of the film  405  and electrical leads  410  only contact the opposite side (polarity) of the film  405 . 
       FIG. 5  illustrates an example of how the power generation section  500  for a shoe may be formed. As shown in  FIG. 5 , an electret film  505  may be rolled. The electret film  505  may be an example of aspects of electret film  105  described with reference to  FIG. 1 . In the embodiment shown, the electret film  505  may be wound around a mechanical support  510 . The purpose of the mechanical support  510  is to enable rolling of the film  505  and to keep the film  505  stack in shape after rolling. The support  510  may be made from low weight material such as plastic or wood or another dielectric material. In addition, electrical contacts (e.g., such as electrical contacts  110  described with reference to  FIG. 1 ) to the film  505  can be made by way of the support. In one embodiment, the support  510  is a circuit board with electrodes patterned for electrical contact to the film  505 . In other embodiments, the mechanical support  510  may be optional. 
     An insulating film  515  may be positioned between the wound layers of the electret film  505  in order that the opposing (polarity) metal surfaces  520  and  525  do not come into electrical contact. In one example, the film thickness is about 50 μm and the total film stack thickness is about 1 cm. Thus, in this example, the total stack would consist of about 100 wraps. The energy output from the film  505  is proportional to the total charge generated. This is proportional to the film area. A larger number of wraps and hence a larger total film area is more readily obtained with a thin film. Some embodiments maintain the film thickness above 10-20 μm as thinner films may be more difficult to handle and process. Although not explicitly show, it will be understood that electrical leads may be attached to metal surfaces  520  and  525  and could connect with a circuit such as illustrated in  FIG. 6 . 
       FIG. 6  illustrates an example of a circuit  600  which may be used in conjunction with a power generating section  605 . The power generating section  605  may be an example of aspects of the tire  200  described with reference to  FIG. 2 , the power generation section  400  described with reference to  FIG. 4 , or the power generation section  500  described with reference to  FIG. 5 . In this circuit  600 , a conventional rectifier  610  may connect to (e.g., electrically couple with) the electrical leads of the folded or rolled electret film from the power generating section  605  (e.g., as shown in  FIG. 4 ) and ensures only a DC current of the correct polarity is directed to a storage device  615  (e.g., a battery) or used immediately. When force is applied to the film of the power generating section  605 , it will generate charge Q. This charge is delivered to the storage device  615  with a voltage V and the total energy is delivered to the storage device  615  is E=QV. In some examples, the storage device  615  may be a battery or a capacitor. 
       FIG. 7  illustrates an example of a circuit  700  that is similar to the circuit  600  described with reference to  FIG. 6 , but further illustrates a conventional stepdown DC to DC converter  715  positioned between rectifier  710  and battery  720 . The step down converter  715  allows higher voltages at the rectifier output than is practical when connecting the rolled/folded electret film stack (e.g., from the power generating section  705 ) directly to a storage device. Because piezoelectric transducers typically have high electrical impedances the output power will be small unless comparatively higher voltages are used. For example, if the DC voltage is 90 V, the energy generated by the transducer is E=QV, is 30 higher than in  FIG. 6  where the power generating section is connected to a 3 volt battery without being stepped down. 
     In some examples the converter  715  may include a voltage input terminal and a voltage output terminal and a first and second capacitor element. The second capacitor element may include a plurality of individual capacitors. The converter  715  may also include a switch network comprising a first phase wherein the plurality of capacitors are in series to the first capacitor element and disconnected from the output terminal. The switch network may also include a second phase wherein the plurality of capacitors are in parallel with the output terminal and disconnected from the first capacitor element. The converter  715  may also include a switch controller that switches to the second phase when a first voltage is created across the first capacitor element and that switches to the first phase when a second, lower voltage is created across the first capacitor element. The switch controller may include an oscillator that turns on when the first voltage is reached. 
     In some examples diodes may be positioned between the individual capacitors in the second capacitor element such that the individual capacitors may be switches between the parallel phase and the series phase. 
       FIG. 8  illustrates an example of the movement of electricity  805  from the tire (or some other energy generating section) to the battery system  810  by means of a wireless charging system  815 . The device may further include a primary charging unit carried within the tire including a charging circuit and a primary coil  820  for inductively providing power to an external capture device including secondary coil  825 . 
     Although the above disclosure has been described in terms of certain specific embodiments, it will be understood that many other obvious modifications and variations may be made to the present invention. All such modifications and variations are intended to fall within the scope of the following claims. 
     The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples. 
     In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. 
     Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.