Energy harvesting module and method for manufacturing the energy harvesting module

Abstract

[0003] Energy harvesting modules, more particularly, energy harvesting modules configured to be coupled to rotatable components of a vehicle wheel, and methods of manufacturing the energy harvesting modules are disclosed. In some embodiments, an energy harvesting system includes a piezoelectric component configured to generate energy in response to mechanical strain applied to the piezoelectric component, the piezoelectric component configured to deform while subjected to the mechanical strain, the piezoelectric component comprising a piezoelectric material layer, one or more electrically conductive bonding layers, a load support layer, and one or more electrode layers, the load support layer comprising a fiber-reinforced composite material.

Description

[Technical Field]

[0001] The present application relates generally to energy harvesting modules, and more particularly to energy harvesting modules configured to be coupled to rotatable components of a wheel of a vehicle. [Background technology]

[0002] In the field of automotive sensor systems, the demand for advanced sensing applications to complement existing electronic safety systems is attracting significant attention. Examples include measuring temperature, pressure, acceleration, and forces (static and dynamic) acting on tires, wheels, and vehicles. All of these sensors require more frequent operation and data transmission, resulting in increased power demands. Current power sources (e.g., lithium-ion batteries) that power these sensors exhibit drawbacks such as limited capacity, low durability, difficulty in replacement, and, most notably, less sustainability in terms of environmental impact. With increased power loads, these power sources are also subjected to accelerated discharge cycles, resulting in frequent or premature replacement of entire sensor modules. This can increase the overall cost of ownership and maintenance for users.

[0003] The foregoing examples of the related art and limitations associated therewith are intended to be illustrative and not exhaustive. Other limitations of the related art will become apparent upon reading this specification and studying the drawings. Summary of the Invention

[0004] The exemplary embodiments disclosed herein are directed to solving one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent from a review of the following detailed description in conjunction with the accompanying drawings. Exemplary systems, methods, devices, and computer program products, according to various embodiments, are disclosed herein. It is understood, however, that these embodiments are presented by way of example, and not limitation, and it will be apparent to those skilled in the art upon reading this disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the invention.

[0005] In one embodiment, the energy harvesting module includes a piezoelectric component configured to generate energy in response to a mechanical strain applied to the piezoelectric component, the piezoelectric component configured to deform while subjected to the mechanical strain, the piezoelectric component comprising a piezoelectric material layer, one or more conductive bonding layers, a load support layer, and one or more electrode layers, the load support layer comprising a fiber-reinforced composite material.

[0006] In one embodiment, the one or more electrode layers include a first electrode layer, the one or more conductive bonding layers include a first conductive bonding layer, the first conductive bonding layer being vertically above and in direct contact with the load support layer, the piezoelectric material layer being vertically above and in direct contact with the first conductive bonding layer, and the piezoelectric material layer being horizontally surrounded by the first electrode layer.

[0007] In some embodiments, the fiber-reinforced composite material includes at least one of a carbon fiber composite (CFC) material, a glass fiber composite material, a carbon nanotube-reinforced composite material, a graphene-reinforced composite material, and a ceramic matrix composite material. In some examples, the fiber-reinforced composite material is in direct contact with the first electrically conductive bonding layer by removing a surface layer of the fiber-reinforced composite material, where removing the surface layer includes a mechanical etching process, an ablation process, a chemical etching process, a polishing process, or a laser etching process.

[0008] In some embodiments, the fiber reinforced composite material has a modulus of elasticity, and the modulus of elasticity after the surface layer is removed is higher than the modulus of elasticity before the surface layer is removed.

[0009] In some embodiments, the one or more electrode layers include a second electrode layer, the one or more conductive bonding layers include a second conductive bonding layer, the second conductive bonding layer is vertically above and in direct contact with the piezoelectric material layer, and the second electrode layer is vertically above and in direct contact with the second conductive bonding layer. In some examples, the one or more conductive bonding layers include a metal powder and a resin.

[0010] In one embodiment, the energy harvesting module includes a piezoelectric component configured to generate energy in response to a mechanical strain applied to the piezoelectric component, the piezoelectric component configured to deform while subjected to the mechanical strain, the piezoelectric component comprising a piezoelectric material layer, one or more conductive bonding layers, a load support layer, one or more electrode layers, and one or more metal layers, and the load support layer comprises a fiber-reinforced composite material.

[0011] In one embodiment, the one or more metal layers include a first metal layer, the one or more electrode layers include a first electrode layer, the one or more conductive bonding layers include a first conductive bonding layer, the first conductive bonding layer being vertically above and in direct contact with the load support layer, the first metal layer being vertically above and in direct contact with the first conductive bonding layer, the first metal layer being electrically connected to the first conductive bonding layer, and the piezoelectric material layer being vertically above the first metal layer and horizontally surrounded by the first electrode layer.

[0012] In certain embodiments, the piezoelectric component further includes one or more interface layers, the one or more interface layers including a first interface layer vertically above and in direct contact with the first metal layer, and a piezoelectric material layer vertically above and in direct contact with the first interface layer.

[0013] In some embodiments, the one or more metal layers include a second metal layer, the one or more electrode layers include a second electrode layer, the one or more conductive bonding layers include a second conductive bonding layer, and the second metal layer vertically overlies the piezoelectric material layer.

[0014] In one embodiment, the second conductive bonding layer is vertically above and in direct contact with the second metal layer, and the second conductive bonding layer is electrically connected to the second metal layer.

[0015] In some embodiments, one or more of the interfacial layers comprises voids.

[0016] In some embodiments, a method includes forming a load-bearing layer including a fiber-reinforced composite material, forming a conductive bonding layer, forming a piezoelectric material layer including a piezoelectric material, forming an electrode layer, sintering the piezoelectric material in the piezoelectric material layer, applying a compound paste on the piezoelectric material to form an interface layer, drying the piezoelectric material, applying a metal paste on the compound paste to form a metal layer, sintering the metal layer and the compound paste, removing a surface layer of the fiber-reinforced composite material by a mechanical etching process, an ablation process, a chemical etching process, or a laser etching process, laminating a conductive bonding layer on the load-bearing layer, laminating the piezoelectric material having the metal layer on the conductive bonding layer, and laminating an electrode layer on the conductive bonding layer surrounding the piezoelectric material layer. In some embodiments, the surface layer includes a resin layer. [Brief explanation of the drawings]

[0017] Various exemplary embodiments of the present invention are described in detail below with reference to the following figures. The figures are provided for illustrative purposes only and merely depict exemplary embodiments of the present invention. These figures are provided to facilitate the reader's understanding of the present invention and should not be considered as limiting the breadth, scope, or applicability of the present invention. It should be noted that for clarity and ease of illustration, the figures have not necessarily been drawn to scale. [Figure 1] FIG. 1 illustrates a smart wheel sensor system incorporating at least one smart wheel, according to various embodiments. [Figure 2] FIG. 1 is a block diagram of an exemplary computing device, according to various embodiments. [Figure 3A] FIG. 1 is a perspective view of a smart wheel, according to various embodiments. [Figure 3B] 1A and 1B are perspective views of a smart wheel without flexible components, according to various embodiments. [Figure 4A] 1 is a perspective view of an energy harvester according to various embodiments. [Figure 4B]FIG. 1 illustrates a top view of an energy harvester according to various embodiments. [Figure 4C] FIG. 1 is a front view of an energy harvester according to various embodiments. [Figure 4D] FIG. 1 is a rear view of an energy harvester according to various embodiments. [Figure 4E] FIG. 1 illustrates a bottom view of an energy harvester according to various embodiments. [Figure 4F] FIG. 1 is a right side view of an energy harvester according to various embodiments. [Figure 4G] FIG. 1 illustrates a left side view of an energy harvester according to various embodiments. [Figure 5A] 1 is a cross-sectional side view of an energy harvester with a piezoelectric component in an unbiased state, according to various embodiments. FIG. [Figure 5B] FIG. 4 is a cross-sectional side view of an energy harvester with a piezoelectric component 404 in a biased state, according to various embodiments. [Figure 6] FIG. 1 illustrates a perspective view of an integrated energy harvester, according to various embodiments. [Figure 7A] 1 illustrates another example of a piezoelectric component according to an embodiment of the present disclosure. [Figure 7B] 1A-1D show top views of a CFC material with a surface layer and a CFC material with the surface layer removed, according to various embodiments. [Figure 8A] 10 illustrates yet another example of a piezoelectric component, according to an embodiment of the present disclosure. [Figure 8B] 1 illustrates a cross-sectional view of a piezoelectric component according to an embodiment of the present disclosure. [Figure 9A] 10 illustrates yet another example of a piezoelectric component, according to an embodiment of the present disclosure. [Figure 9B] 1 illustrates another cross-sectional view of a piezoelectric component according to an embodiment of the present disclosure. [Figure 10A] 10 illustrates yet another example of a piezoelectric component, according to an embodiment of the present disclosure. [Figure 10B] 10 illustrates yet another example of a cross-sectional view of a piezoelectric component according to an embodiment of the present disclosure. [Figure 11A]10 illustrates yet another example of a piezoelectric component, according to an embodiment of the present disclosure. [Figure 11B] 10 illustrates yet another example of a piezoelectric component, according to an embodiment of the present disclosure. [Figure 11C] 10 illustrates yet another example of a cross-sectional view of a piezoelectric component according to an embodiment of the present disclosure. [Figure 12] 1 illustrates improved power generation using carbon fiber composite materials compared to steel materials, according to various embodiments. [Figure 13] 1 is a flowchart of an energy harvester process according to various embodiments. [Figure 14] 1 illustrates an exemplary method for manufacturing a piezoelectric component, according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] Various exemplary embodiments of the present invention are described below with reference to the accompanying figures to enable those skilled in the art to make and use the present invention. As will be apparent to those skilled in the art, after reading this disclosure, various changes or modifications can be made to the examples described herein without departing from the scope of the present invention. Thus, the present invention is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, any specific order or hierarchy of steps in the methods disclosed herein is merely an example approach. Based on design preferences, the specific order or hierarchy of steps in a disclosed method or process can be rearranged while remaining within the scope of the present invention. Thus, those skilled in the art will understand that the methods and techniques disclosed herein present various steps or operations in a sample order, and that the present invention is not limited to the specific order or hierarchy presented, unless expressly stated otherwise.

[0019] As discussed above, batteries or other disposable energy sources that power vehicle sensor systems exhibit drawbacks such as limited capacity, low durability, difficulty in replacement, and poor environmental sustainability. An alternative to disposable batteries in vehicle sensor systems involves harvesting energy from the environment. Accordingly, novel systems and methods are disclosed herein that utilize energy harvesters to harvest energy from the environment proximate to the wheels, according to various embodiments. These energy harvesters can be devices that convert energy from various sources, such as kinetic energy, heat, light, and / or mechanical energy, into usable electrical energy, according to various embodiments. For example, the energy harvester can utilize piezoelectric transduction to convert tire deformation into electrical energy. The amount of this energy conversion can vary based on the rotational speed of the wheel (e.g., the vehicle's speed as determined by the driver). Additionally, in some embodiments, the energy harvester can be positioned on the wheel rim to more effectively capture energy.

[0020] In various embodiments, the energy harvester may generate sustained power output at various vehicle speeds based on the weight of the vehicle acting through the rim and tire on an underlying surface (e.g., a road). For example, a vehicle may have wheels (e.g., wheels with pneumatic tires). A wheel with an inflated tire and a rigid rim can impart vehicle motion along the bead area of ​​the tire that interfaces with the rigid rim. These vehicle motions may include traction, braking, steering, load bearing, etc. As the wheel rotates, the bottom of the tire may exert forces on the bead area to counteract the weight of the vehicle. These forces may cause the sidewall of the wheel to flex due to the internal air pressure of the tire (e.g., due to intimate contact between the rubber tire and metal rim).

[0021] In various embodiments, the energy harvester may include a substrate and a piezoelectric component. The substrate may be positioned behind (e.g., proximate to) the piezoelectric component to form a cavity that allows the force of the vehicle during motion (e.g., wheel rotation) to displace (e.g., strain or bend) the piezoelectric component to generate an electric charge (e.g., electrical energy). Thus, the energy harvester as a piezoelectric substrate assembly may be arranged along the periphery of the rim and generate continuous power as the wheel rotates. In some embodiments, when the energy harvester is attached to the rim of the wheel, the energy harvester may be separate from the rim and / or tire. Thus, the energy harvester does not need to be replaced or modified when the tire is changed. The energy harvester may also be coupled with an energy storage device (e.g., a rechargeable battery) to provide a recharge cycle that can power an array of sensors located in, on, or proximate to the wheel.

[0022] In some embodiments, the piezoelectric component may utilize strain (e.g., mechanical strain indicative of relative motion / deflection) to generate an electric charge. Additionally, the substrate may be structured to facilitate the development of strain (e.g., relative motion / deflection) in the piezoelectric component when placed between the tire and rim of a wheel.

[0023] In various embodiments, the substrate may have a geometry and be located in a high power density area of ​​the wheel to increase strain (e.g., energy generation) from the piezoelectric components mounted on the substrate. Stated another way, the energy harvester may be a mechanism with specific internal and external geometries that sits between the wheel and tire that converts mechanical force (vehicle weight) and locomotion into usable strain that is generated in the piezoelectric components.

[0024] In some embodiments, the energy harvester may harvest energy from mechanical loads applied to the wheel. For example, the load of the vehicle and forces applied by the vehicle in the presence of a mechanical substrate may induce strains in the piezoelectric components that generate substantial electrical power that can be utilized to power electronic or sensing systems within the vehicle and / or wheel.

[0025] In some embodiments, the energy harvester, including the piezoelectric component and substrate, can be modular and scalable to fit a variety of wheel diameters, energy requirements, and sensor locations. In further embodiments, the substrate can encapsulate the piezoelectric component and other electronics mounted thereon, protecting them from degradation due to exposure. In yet further embodiments, the energy harvester can include the piezoelectric component and a region of the wheel (e.g., a staging surface) configured or constructed to induce strain on the piezoelectric component.

[0026] In various embodiments, the substrate can include a three-dimensionally curved bottom surface that interfaces with the rim (e.g., a rotatable component of a wheel that is separate from the tire (e.g., flexible component) of the wheel). The three-dimensionally curved bottom surface can include a compound curve in three dimensions (e.g., length, height, and width). The length, height, and width can each define mutually orthogonal directions or axes in three-dimensional physical space. For example, the length can be along an axis orthogonal to the height, the height can be along an axis orthogonal to the width, and the width can be along an axis orthogonal to the length. In some embodiments, the length, height, and width can be referred to as the x-axis, z-axis, and y-axis. The substrate can also include a two-dimensionally (e.g., two of the length, height, and width) curved staging surface (e.g., a microcavity or depression) opposite the bottom surface of the substrate. In some embodiments, the two-dimensionally curved staging surface can be convexly or concavely curved, and the piezoelectric component can undergo strain to deform and conform to the two-dimensionally curved staging surface. Thus, the rectangular piezoelectric component can be configured to flex to conform to a two-dimensionally curved staging surface (e.g., by being fixed onto a substrate having a three-dimensionally curved bottom surface) while seated on a rim via a three-dimensionally curved bottom surface.

[0027] In certain embodiments, the piezoelectric component may be formed of multiple layers. For example, the piezoelectric component may include a load-bearing layer. The load-bearing layer may include, for example, a fiber-reinforced composite material having sufficient load flexibility to hold the piezoelectric component together. The piezoelectric component may further include a central piezoelectric material layer that may be configured to generate an electric charge when mechanically deformed. The piezoelectric component may further include an electrode layer that may be formed as a mesh with the central piezoelectric material layer to more effectively harvest the electric charge from the central piezoelectric material layer. In certain embodiments, the electrode layer may include an electrode that is embedded in (e.g., held in place by) a flexible material (e.g., epoxy) and in direct or indirect contact with the piezoelectric material layer.

[0028] In some embodiments, the electrode layer can include flexible interconnects with the electrodes and a flexible material that holds the electrodes and flexible interconnects in place. The flexible interconnects can be configured to electrically connect the electrodes in the electrode layer to other electrical components (e.g., pressure sensors) coupled to the wheel to provide power to the other electrical components or for the other electrical components to perform measurements based on signals received from the flexible interconnects.

[0029] In some embodiments, the piezoelectric component includes two electrode layers, a piezoelectric material layer, two conductive bonding layers, a load-supporting layer, and an electrical wire connected to the first of the two electrode layers. The second of the two electrode layers can be used to indirectly contact the piezoelectric material layer and harvest charge from the piezoelectric material layer. In some embodiments, the two electrode layers can represent different circuits with different potentials such that a potential difference exists between the two electrode layers. Thus, the potential difference between the two electrode layers can be used to power a device of the smart wheel sensor system via the electrical wire. In some embodiments, the piezoelectric material layer is surrounded by the first electrode layer with a gap between the inner and outer peripheries of the first electrode layer to prevent short circuits between the piezoelectric material layer and the first electrode layer. In some embodiments, the gap is 100 μm or greater.

[0030] In various embodiments, the piezoelectric component can be adapted to undergo strain (e.g., generate energy) in any type of wheel to which a force (e.g., to generate strain) is applied during rotation. Examples of different types of wheels can include wheels with pneumatic tires, wheels with airless tires (e.g., non-pneumatic tires or flat-free tires), cylindrical wheels, and spherical wheels. In additional embodiments, the piezoelectric component can be bonded directly to the wheel (e.g., without a substrate) to undergo strain and deform along with the portion of the wheel that can deform in response to a load. For example, the piezoelectric component can be bonded along the outer surface of a spherical tire, along the spokes of an airless tire, or to any other component of the wheel that can deform in response to a load.

[0031] It should be noted that although certain embodiments may refer to piezoelectric components having a particular number of layers in a particular order, the piezoelectric component may include any number of layers in any order as desired for different applications in various embodiments. For example, a piezoelectric component may include four layers, where a load-bearing layer is connected to a top electrode layer, which is connected to a piezoelectric material layer, which is connected to a bottom electrode layer.

[0032] In various embodiments, the energy harvester may be part of a smart wheel sensor system for providing power to at least one sensor of the smart wheel sensor system. For example, the energy harvester may be arranged on a wheel of a vehicle (e.g., a wheel-driven object) along with other sensors of the smart wheel sensor system. The smart wheel sensor system may include multiple types of sensors, each configured to collect different types of smart wheel sensor system data. For example, the smart wheel sensor system may include a height sensor configured to generate barometric pressure sensor data, an acoustic sensor configured to generate acoustic sensor data, an image sensor configured to generate image sensor data, a gas sensor configured to generate gas sensor data, a magnetic sensor configured to generate magnetic sensor data, an accelerometer sensor configured to generate acceleration sensor data, a gyroscope sensor configured to generate gyroscope sensor data, and a humidity sensor configured to generate humidity sensor data. The smart wheel sensor system data generated by the smart wheel sensor system may be analyzed both centrally and locally at a vehicle that relies on the smart wheels for movement (e.g., by a computer or server within or supported by the body of the vehicle) to determine the state of the vehicle and / or individual smart wheels. Advantageously, a smart wheel sensor system may be implemented in an autonomous vehicle as part of a backup sensor system to enhance the safety systems of the autonomous vehicle. In various embodiments, the individual wheels on which the smart wheel sensor system devices are arranged may be referred to as smart wheels.

[0033] 1 is a diagram of a smart wheel sensor system 100 incorporating at least one smart wheel 102, according to various embodiments. The smart wheel sensor system 100 may include a local sensor system 104 (e.g., a local smart wheel sensor system) having a device platform 106 arranged on each smart wheel 102. The device platform 106 may represent a device on the smart wheel, such as an energy harvester and / or a sensor powered by the energy harvester.

[0034] The local sensor system 104 may include a local smart wheel server 108 that communicates with sensors in the device platforms 106. Thus, each device platform 106 may include at least one sensor and may also include an auxiliary interface, such as a communication interface, for communicating with the local smart wheel server 108. The local smart wheel server 108 may also communicate with a local smart wheel data store 110 and any local user devices 112, such as smartphones. For ease of explanation, the term local may refer to devices coupled in or on the body 114 or smart wheel 102 of the vehicle 116.

[0035] In contrast, the term remote may refer to a device that is external to the body 114 of the vehicle 116 or the smart wheel 102. For example, the local smart wheel server 108 may be configured to communicate with a remote network 120, such as the Internet. This remote network 120 may further connect the local smart wheel server 108 to a remote server 122 that communicates with a remote data store 124, or a remote user device 126. Additionally, the local smart wheel server 108 may communicate with external sensors or devices, such as remote satellites 128 for global positioning system (GPS) information.

[0036] In various embodiments, at least some of the devices of the device platform 106 may be configured to communicate with the local smart wheel server 108 via a communication interface. This communication interface may allow the devices to communicate with each other using any communication medium and protocol. Thus, the communication interface 280 may include any suitable hardware, software, or combination of hardware and software capable of coupling the device platform 106 with the local smart wheel server 108. The communication interface may be configured to operate with any suitable technology for controlling information signals using a desired set of communication protocols, services, or operating procedures. The communication interface may comprise an appropriate physical connector for connecting to a corresponding communication medium. In some embodiments, this communication interface may be separate from a controller area network (CAN) bus. For example, the communication interface may facilitate wireless communication within the local sensor system 104 (e.g., between the device platform 106 and the local smart wheel server 108). Further description of such communication interfaces is provided in more detail below.

[0037] In an embodiment, at least some of the devices of device platform 106 may be configured to communicate with remote network 120. For example, sensor data generated by sensors of device platform 106 may be communicated via remote network 120 to remote server 122, remote data store 124, remote user device 126, and / or remote satellite 128. In various embodiments, certain devices of device platform 106 may communicate directly with remote network 120. For example, certain devices of device platform 106 may include a communication interface (described further below) that may be configured to communicate directly with remote network 120 in a manner that bypasses local server 108. In other embodiments, certain devices of device platform 106 may communicate indirectly with remote network 120. For example, a particular device of device platform 106 may include a communication interface (described further below) that may be configured to communicate indirectly with remote network 120 via local server 108, which in turn includes one or more communication interfaces (described further below) for communicating with external devices via various communication protocols (e.g., LTE, 5G, etc.), as described in more detail below.

[0038] These communications from the device platform 106 to the remote server 122, whether direct or indirect, may include sensor data collected by the device platform for analysis by the remote server 122. According to various embodiments, this sensor data may be analyzed by the remote server 122 to determine actions that may be performed by the local server 108. For example, as described in further detail below, this sensor data may be utilized to determine parameter values. A particular action may then be performed (e.g., an alert or notification presented via a user interface) based on the state of the parameter value, for example, in response to the parameter value meeting a certain threshold. This determination of the parameter value may be performed at the remote server 122, and the parameter value may then be communicated to the local server 108 to determine the action to be performed based on the state of the parameter value. In other embodiments, both the determination of the parameter value and the resulting determination of the action may be performed by the remote server 122. The remote server 122 may then communicate instructions of the action to be performed to the local server 108 for implementation (e.g., as instructions to the local server 108 to implement). Although in some embodiments, the sensor data is described as being communicated to a remote server for processing, the sensor data may be processed in other manners as desired for different applications according to various embodiments. For example, the sensor data may be processed locally at the local server 108, with or without additional input provided from a remote server 122, a remote user device 126, and / or a remote satellite 128, as described further below. In some embodiments, the device platform 106 may communicate directly with a user device 112 (e.g., a smartphone), which may then communicate directly or indirectly with the local server 108, the remote network 120, the remote user device 126, and / or the remote satellite 128.In further embodiments, the wheel 102 (e.g., acting as an antenna) and / or the sensor platform 106 may have a direct communication link with a remote user device 126 or a remote satellite 128 (e.g., for internet access and / or GPS purposes).

[0039] FIG. 2 is a block diagram of an exemplary computing device 200, according to various embodiments. As noted above, computing device 200 may represent an exemplary component of a particular local smart wheel server 108, local user device 112, remote server 122, remote user device 126, some devices of device platform 106 (e.g., sensors of the device platform), or remote satellite 128, as described above in connection with FIG. 1. Returning to FIG. 2, in some embodiments, computing device 200 includes hardware unit 225 and software 226. Software 226 may execute on hardware unit 225 (e.g., a processing hardware unit), thereby enabling various applications or programs to be executed on hardware unit 225 by software 226. In some embodiments, functionality of software 226 may be implemented directly in hardware unit 225 (e.g., as a system-on-chip, firmware, field-programmable gate array (“FPGA”), etc.). In some embodiments, hardware unit 225 includes one or more processors, such as processor 230. In some embodiments, processor 230 is an execution unit or "core" on a microprocessor chip. In some embodiments, processor 230 may include a processing unit such as, but not limited to, an integrated circuit ("IC"), an application specific integrated circuit (ASIC), a digital signal processor (DSP), an attached support processor (ASP), a microcomputer, a programmable logic controller ("PLC"), and / or any other programmable circuit. Alternatively, processor 230 may include multiple processing units (e.g., in a multi-core configuration).The above examples are illustrative only and thus do not in any way limit the definition and / or meaning of the term "processor." Hardware unit 225 also includes system memory 232 coupled to processor 230 via system bus 234. Memory 232 can be general-purpose volatile RAM. For example, hardware unit 225 can include a 32-bit microcomputer with 2 Mbits of ROM and 64 Kbits of RAM, and / or gigabytes of RAM. Memory 232 can also be ROM, a network interface (NIC), or any combination of known volatile and / or non-volatile memory devices having appropriate capacities for various desired applications, according to various embodiments.

[0040] In some embodiments, a system bus 234 may couple each of the various system components together. Note that, as used herein, the term "couple" is not limited to a direct mechanical, communicative, and / or electrical connection between components, but may also include an indirect mechanical, communicative, and / or electrical connection between two or more components, or a coupling that is operable through an intermediary element or space. The system bus 234 may be any of several types of bus structure(s), including a memory bus or memory controller, a peripheral or external bus, and / or a local bus using any of a variety of available bus architectures, including, but not limited to, a 9-bit bus, Industrial Standard Architecture (ISA), Micro-Channel Architecture (MSA), Extended ISA (EISA), Intelligent Drive Electronics (IDE), VESA Local Bus (VLB), Peripheral Component Interconnect Card International Association Bus (PCMCIA), Small Computers Interface (SCSI), other proprietary buses, or any custom bus suitable for computing device applications.

[0041] In some embodiments, computing device 200 may also optionally include at least one media output component or display interface 236 for use in presenting information to a user. Display interface 236 may be any component capable of communicating information to a user and may include, but is not limited to, a display device (not shown) (e.g., a liquid crystal display (“LCD”), an organic light emitting diode (“OLED”) display, or an audio output device (e.g., a speaker or headphones). In some embodiments, computing device 200 may provide at least one desktop interface, such as desktop 240. Desktop 240 may be an interactive user environment provided by an operating system and / or applications executing within computing device 200 and may include at least one screen or display image, such as display image 242. Desktop 240 may also accept input from a user in the form of device input, such as keyboard input and mouse input. In some embodiments, desktop 240 may also accept simulated input, such as simulated keyboard input and mouse input. In addition to user input and / or output, desktop 240 may send and receive device data, such as input and / or output to a flash memory device local to the user, or to a local printer.

[0042] In some embodiments, computing device 200 includes an input interface 250 or user interface 250 for receiving input from a user. User interface 250 may include, for example, a keyboard, a pointing device, a mouse, a stylus, a touch-sensitive panel (e.g., a touchpad or touchscreen), a position detector, and / or an audio input device. A single component, such as a touchscreen, may function as both an output device and an input interface for a media output component. In some embodiments, a mobile device, such as a tablet, may be used.

[0043] In some embodiments, computing device 200 may include database 260 as a data store in memory 232, such that various information may be stored in database 260. Alternatively, in some embodiments, database 260 may be included in a remote server (not shown) with file sharing capabilities, such that database 260 may be accessed by computing device 200 and / or remote end users. In some embodiments, computer-executable instructions may be stored in memory 232, such as in one or more computer-readable storage media 270 (only one shown in FIG. 2). Computer-readable storage media 270 includes non-transitory media and may include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules, or other data. The instructions may be executed by processor 230 to perform various functions described herein.

[0044] 2, computing device 200 may be a communication device, a storage device, or any device capable of executing software components. In non-limiting examples, computing device 200 may be, but is not limited to, a local smart wheel server, a local user device, a remote server, a remote user device, a device platform device, a remote satellite, a smartphone, a laptop PC, a desktop PC, a tablet, a Google™ Android™ device, an iPhone®, an iPad®, and a voice-controlled speaker or controller.

[0045] Computing device 200 has a communication interface 280 that allows computing device 200 to communicate with users and other devices using one or more known communication media and protocols, which may be, but are not limited to, the Internet, an intranet, a wide area network (WAN), a local area network (LAN), a wireless network, Bluetooth, WiFi, and a mobile communication network.

[0046] In some embodiments, communications interface 280 may include any suitable hardware, software, or combination of hardware and software capable of coupling computing device 200 to one or more networks and / or additional devices. Communications interface 280 may be configured to operate with any suitable technology for controlling information signals using a desired set of communications protocols, services, or operating procedures. Communications interface 280 may comprise appropriate physical connectors for connecting to a corresponding communications medium, whether wired or wireless. In some embodiments, communications interface 280 includes radio frequency (RF) communications circuitry and at least one antenna for transmitting and receiving RF signals according to various known communications protocols (e.g., LTE, 5G, Wi-Fi, etc.).

[0047] A communication network may be utilized as a means of communication. In various aspects, the network may include a local area network (LAN) and a wide area network (WAN), including, but not limited to, the Internet, wired channels, wireless channels, communication devices including telephones, computers, wired, wireless, optical or other electromagnetic channels, and combinations thereof, as well as other devices and / or components capable of communicating data or associated with communicating data. For example, the communication environment may include intrabody communication, various devices, and various communication modes such as wireless communication, wired communication, and combinations thereof.

[0048] Wireless communication modes include any communication modes between points (e.g., communication nodes) that utilize, at least in part, wireless technology, including radio transmissions, data, and various protocols and combinations of protocols associated with the devices. Communication nodes may include, for example, wireless devices such as mobile terminals, fixed terminals, base stations, access points, smartphones, and other known devices capable of wireless communication via various wireless communication protocols. Further examples of communication nodes may include wireless headsets, audio and multimedia devices and appliances such as audio and multimedia players, telephones including cellular and cordless telephones, and computers and computer-related devices and components such as printers, network-connected machines, and / or any other suitable or third-party device.

[0049] Wired communication modes include any communication mode between points that utilize wired technology, including wired transmission, data, and various protocols and combinations of protocols associated with devices. Points include, for example, devices such as audio and multimedia devices and appliances, such as audio and multimedia players, telephones, including cellular and cordless telephones, and computers, computer-related devices, and components, such as printers, networked machines, and / or any other suitable or third-party devices. In various implementations, wired communication modules may communicate according to several wired protocols. Examples of wired protocols may include Universal Serial Bus (USB) communications, RS-232, RS-422, RS-423, RS-485 serial protocols, FireWire, Ethernet, Fibre Channel, MIDI, ATA, Serial ATA, PCI Express, T-1 (and its variants), Industry Standard Architecture (ISA) parallel communications, Small Computer System Interface (SCSI) communications, or Peripheral Component Interconnect (PCI) communications, to name just a few.

[0050] Thus, in various aspects, communication interface 280 may include one or more interfaces, such as, for example, a wireless communication interface, a wired communication interface, a network interface, a transmit interface, a receive interface, a media interface, a system interface, a component interface, a switching interface, a chip interface, a controller, etc. When implemented by a wireless device or within a wireless system, for example, communication interface 280 may include a wireless interface that comprises (e.g., includes) one or more antennas, transmitters, receivers, transceivers, amplifiers, filters, control logic, etc.

[0051] In various aspects, communication interface 280 may provide data communication functions according to several protocols. Examples of protocols may include various wireless local area network (WLAN) protocols, including the IEEE 802.xx series of protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11a / b / g / n, IEEE 802.16, and IEEE 802.20. Other examples of wireless protocols may include various wireless wide area network (WWAN) protocols, such as the GSM cellular radiotelephone system protocol with GPRS, the CDMA cellular radiotelephone communication system with 1xRTT, the EDGE system, the EV-DO system, the EV-DV system, the HSDPA system, 4G-LTE, and 5G (new wireless). Further examples of wireless protocols may include wireless personal area network (PAN) protocols, such as infrared protocols, protocols from the Bluetooth Special Interest Group (SIG) series of protocols, including Bluetooth Specification versions v1.0, v1.1, v1.2, v2.0, and v2.0 with Enhanced Data Rate (EDR), as well as one or more Bluetooth profiles. Further examples of wireless protocols may include short-range communication techniques and protocols, such as electromagnetic induction (EMI) techniques. An example of an EMI technique may include passive or active radio-frequency identification (RFID) protocols and devices. Other suitable protocols may include Ultra Wide Band (UWB), Digital Office (DO), Digital Home, Trusted Platform Module (TPM), ZigBee, and the like.

[0052] FIG. 3A is a perspective view of a smart wheel 300, according to various embodiments. The smart wheel 300 may include a device platform 302 for at least one device. More specifically, the device platform 302 may include at least one device that is a sensor within a sensor housing 304 and at least one device that is an energy harvester 306. The device platform may be supported by (e.g., positioned along) a rotatable component 308 of the smart wheel 300. The rotatable component 308 may include, for example, a rim of the smart wheel 300, with the periphery of the rotatable component 308 coupled within the smart wheel 300. While the device platform is illustrated with eight pairs of sensor housings 304 and energy harvesters 306, any number of sensor housings and energy harvesters may be implemented on the device platform as desired for different applications in various embodiments. For example, other embodiments may include multiple sensor housings for each energy harvester, and yet further embodiments may include multiple energy harvesters for each sensor housing. While in one embodiment the sensor housing 304 is described as being located directly on the rim 308A of the smart wheel 300 (e.g., on the rim of the rotatable component 308 of the smart wheel 300), the sensor housing may also be located on other portions of the smart wheel 300 as desired for different applications in various embodiments. For example, the sensor housing (and constituent sensors) may be located closer to the center of the rotatable component 308 in certain embodiments, such as along the spokes 308B of the rotatable component 308 or around the center 308C of the rotatable component 308 (e.g., adjacent to the cap).

[0053] In various embodiments, the sensor housing may represent one or more sensors together within the sensor housing, along with a functional module, such as a battery or other energy storage medium, configured to store energy generated by the energy harvester. In some embodiments, the sensor housing may include a system bus (e.g., conductive elements of a printed circuit board) that connects various portions of the sensor housing together.

[0054] Additionally, the sensor housing may include other functional modules, such as a communications interface for communicating sensor data captured by the various sensors of the sensor housing to a local smart wheel server. This communications interface may include, for example, a communications interface for data offload (e.g., via millimeter-wavelength and / or gigahertz-wavelength communications) to the local smart wheel server, other vehicles, infrastructure (e.g., a remote network), and / or user devices. As a further example, this communications interface may facilitate wireless communications, such as via Bluetooth, radio frequency, radio waves, ultrasonic waves, and / or any other type of communications protocol or medium. This communications interface may be configured to communicate, for example, with electronic control units (ECUs) and / or advanced driver-assistance (ADAS) systems onboard the vehicle. Additionally, the sensor housing may optionally include a processor or any other circuitry for facilitating collection, communication, and / or analysis of sensor data generated by the constituent sensors of the sensor housing.

[0055] According to various embodiments, various types of sensors may be integrated with the sensor housing. For example, the sensor housing may include an impact sensor that can sense the amount of electrical potential generated by the energy harvester. The impact sensor may be configured to wake up or otherwise activate sensors and / or functional modules of the sensor housing when a sufficient amount of electrical potential is generated by the energy harvester. Stated differently, the impact sensor may conceptually include the energy harvester, whereby the impact sensor is configured to transition various sensors and / or functional modules of the sensor housing from a low-power or inactive state to a powered-on or active state based on the energy harvester generating more than a threshold amount of energy in response to mechanical deformation. In some embodiments, the energy sensed by the impact sensor may be stored in a battery for standby power when the energy harvester is not generating any energy (e.g., when no mechanical stress is being applied to the energy harvester).

[0056] In certain embodiments, the sensor housing may include a height sensor configured to generate barometric pressure sensor data. The height sensor may therefore be a barometric pressure sensor or barometric air pressure sensor capable of measuring atmospheric pressure, which may indicate altitude or elevation. This barometric pressure sensor data may be utilized, for example, to determine the height of the smart wheel from a reference point, such as the road, and / or relative to other smart wheels on the vehicle. This may enable rollover risk or flat tire determination. As noted above, the height sensor on the smart wheel may be on a rotatable component of the wheel and thus not on the vehicle chassis. Such a height sensor may therefore be capable of providing barometric pressure sensor data regarding which side (e.g., which smart wheel) initiated a rollover (e.g., if such barometric pressure sensor data is generated and recorded continuously or semi-continuously). Furthermore, barometric pressure sensor data generated by the smart wheel may enable more accurate detection of road conditions, such as potholes, compared to sensor data generated from a stationary portion of the vehicle chassis. In some embodiments, the height sensor is also configured to measure deflection of the inner tire surface due to vehicle load or contact patch. In some embodiments, a distance measurement sensor may be positioned within the pressurized portion of the tire. As the tire rotates, the distance of the tire relative to the central rotating rim changes, and this cyclical change in distance can be detected.

[0057] In further embodiments, the sensor housing may include an acoustic sensor configured to generate acoustic sensor data. The acoustic sensor may therefore be any type of acoustic, sound, or vibration sensor, such as a geophone, microphone, seismometer, and sound source detector. The acoustic sensor data may be utilized for audio pattern recognition, such as to sense the audio signature of brakes or rotors on rotatable components (e.g., wheels). This may be used to predict vehicle maintenance schedules and / or generate performance optimization data. In some embodiments, the acoustic sensor data may be analyzed to identify and / or monitor unique signatures for, for example, different damage and wear conditions.

[0058] In various embodiments, the sensor housing may include an image sensor configured to generate image sensor data from the variable attenuation of the waves. Examples of image sensors may include semiconductor charge-coupled devices (CCDs) or active pixel sensors in complementary metal-oxide-semiconductor (CMOS) or N-type metal-oxide-semiconductor (NMOS) technologies. In various embodiments, the device platform including the image sensor may include a lens or other transparent medium on which light waves are focused onto the image sensor from outside the sensor housing. In certain embodiments, the image sensor may include a time-of-flight (TOF) sensor for capturing time-of-flight data that may characterize time-of-flight (TOF). The TOF sensor may be, for example, an ultrasonic TOF sensor configured to collect ultrasonic TOF sensor data. As a more specific example, the image sensor may function as a camera for determining tire tread depth visibility to evaluate tire performance and optimization. Such an image sensor capturing image data characterizing the tire tread depth may also be positioned in a manner that allows it to capture image data of the tire tread (e.g., by having such an image sensor capture image data characterizing the tread depth of a smart tire in which the image sensor is positioned, or image data characterizing the tread depth of a tire in which the image sensor is not positioned). According to various embodiments, the image sensor may be located either inside or outside the rim so that the sensor can image the tire sidewall. In either case, the image sensor may be electrically coupled to an energy harvester. As another example, the image sensor may include an infrared image sensor for authentication or identification. This infrared sensor may be utilized, for example, to scan characteristics of the local environment or local objects (e.g., a person approaching the vehicle) for authentication.

[0059] In certain embodiments, the sensor housing may include a gas sensor configured to generate gas sensor data. The gas sensor may be any type of sensor that monitors and characterizes the gas atmosphere. For example, the gas sensor may utilize any of a variety of mechanisms for gas detection, such as electrochemical gas sensors, catalytic bead gas sensors, photoionization gas sensors, infrared point gas sensors, thermographic gas sensors, semiconductor gas sensors, ultrasonic gas sensors, holographic gas sensors, etc. These gas sensors may detect, for example, specific types of gases, such as exhaust gases, explosive gases (e.g., for battery failure detection), atmospheric humidity, air quality, particulates, pH levels, etc.

[0060] In certain embodiments, the sensor housing may include a magnetic sensor configured to generate magnetic sensor data, such as a magnetometer that measures magnetism for navigation (e.g., inside a building or enclosed environment) using a magnetic field map.

[0061] In additional embodiments, the sensor housing may include an accelerometer sensor configured to generate acceleration sensor data and / or a gyroscope sensor configured to generate gyroscope sensor data. This acceleration sensor data and / or gyroscope sensor data may be utilized for navigation, such as to determine the amount of acceleration for emergency braking system applications. In some embodiments, the accelerometer sensor and / or gyroscope sensor may be part of an inertial navigation system (INS) located on the smart wheel.

[0062] The energy harvester 306 may be disposed along the rotatable component 308 (e.g., rim) of the smart wheel 300 in a manner configured to capture kinetic energy in response to compressive forces acting on a flexible component 310 (e.g., pneumatic or inflatable tire, tube, etc.) of the smart wheel 300 that contacts the road or an object as the rotatable component 308 rotates. In some embodiments, the energy harvester 306 and / or the device platform 302 may be visible from the side of the vehicle or smart wheel 300 (e.g., adjacent to the lateral sidewall of the vehicle or smart wheel 300). However, in other embodiments, the energy harvester 306 and / or the device platform 302 may not be visible from the side of the vehicle or smart wheel 300. The energy harvested by the energy harvester 306 may be used to power various components of the device platform 302, such as various sensors and / or communication interfaces within the sensor housing 304, as described in further detail below.

[0063] In various embodiments, the energy harvester 306 may be disposed on a sidewall of the rotatable component 308. For example, the energy harvester 306 may be disposed between a bead region of the flexible component 310 (e.g., a tire, a tube, a belt, etc.) and the rotatable component 308 (e.g., a rim, a shaft, etc.). Thus, the flexible component 310 may be attached to the rotatable component 308. The energy harvester 306 may generate energy resulting from compressive forces acting on the bead region of the flexible component 310 (e.g., a tire, a tube, etc.) as the vehicle moves over a surface (e.g., a road).

[0064] 3B is a perspective view of a smart wheel 300 without flexible components, according to various embodiments. As shown, the energy harvester 306 may be disposed along the periphery of the rotatable component 308. Thus, the energy harvester 306 may generate energy resulting from the compressive force of a moving object (e.g., a vehicle acting on the bead area of ​​a tire attached to the rotatable component 308). In some embodiments, the compressive force may be due to a load (e.g., acceleration, deceleration, etc.). Thus, the location of the compressive force may change depending on the load. In further embodiments, the energy harvester 306 may capture the kinetic energy of a vehicle moving in response to the rotation of the rotatable component 308. Thus, the energy harvester 306 may generate energy when a mechanical stress is applied to the energy harvester 306.

[0065] 4A is a perspective view 400A of an energy harvester 306, according to various embodiments. The energy harvester 306 may be disposed along the periphery of the rotatable component 308 (e.g., a rim). The energy harvester 306 may include a substrate 402 configured to contact and fixedly couple to the rotatable component 308. The substrate 402 may support a piezoelectric component 404. The piezoelectric component may be a transducer that converts mechanical deformation into energy, according to some embodiments.

[0066] The energy harvester 306 may include a conductive component 406 configured to direct and offload energy generated by the piezoelectric component 404. This conductive component may be connected to other devices of the device platform (e.g., a sensor in a sensor housing) to provide power to other devices of the device platform. In some embodiments, this conductive component 404 may be constructed from a flexible conductive material such as brass or copper. The energy harvester 306 may also include locating pins 408 by which the piezoelectric component 404 may be secured to the substrate 402. For example, the piezoelectric component 404 may include wingtip features 409 having apertures configured so that the locating pins 408 can pass through the apertures and secure the piezoelectric component to the substrate 402 in a secure manner, as described in further detail below.

[0067] In various embodiments, the substrate 402 may include a three-dimensionally curved bottom surface 410 that interfaces with the rotatable component 308 (e.g., a rim) of the smart wheel. The three-dimensionally curved bottom surface 410 may include compound curves in three dimensions (e.g., length, height, and width). As described above, the length, height, and width may each define mutually orthogonal directions or axes in three-dimensional physical space. For example, the length may be along an axis orthogonal to the height, the height may be along an axis orthogonal to the width, and the width may be along an axis orthogonal to the length. In some embodiments, the length, height, and width may be referred to as the x-axis, z-axis, and y-axis, respectively. The substrate 402 may also include a curved staging surface 412 (e.g., a microcavity or depression) opposite the bottom surface 410. The staging surface 412 (e.g., a top surface) may be referred to as the top surface of the substrate. In some embodiments, the curved staging surface 412 is curved in only two of two dimensions (length, height, and width), for example, as described in more detail below. When a force is applied to the piezoelectric component 404, the piezoelectric component 404 deforms to conform to the two-dimensionally curved staging surface 412, thereby limiting the amount of deformation of the piezoelectric component 404. Thus, the piezoelectric component 404 can seat on the rotatable component 308 via the three-dimensionally curved bottom surface 410. Additionally, the rectangular piezoelectric component 404 can be configured to bend within the two-dimensionally curved staging surface 412. In some embodiments, the two-dimensionally curved staging surface 412 can be referred to as a convex surface. Thus, the two-dimensionally curved staging surface 412 can be configured to bend within the two-dimensionally curved staging surface 412. The staging surface 412 may include (e.g., may be convex) a convex surface to which a piezoelectric component 404 having a straight (e.g., non-curved or flat) shape or surface may be attached. In some embodiments, the substrate 402 may be referred to as a teardrop support. Thus, the piezoelectric component 404 may be bent relative to the convex, two-dimensionally curved staging surface 412 to generate a compressive bending strain on the piezoelectric component 404. In other words, the piezoelectric component 404 may be subjected to a strain that causes the piezoelectric component 404 to bend to conform to the convex, two-dimensionally curved staging surface 412 (e.g., bend relative to the convex surface) and generate an electric charge (e.g., via mechanical deformation of the piezoelectric material layer).Thus, the substrate 402 may be structured to allow distortion (e.g., relative movement / deflection) of the piezoelectric component 404 when placed between the wheel tire and the rotatable component 308 (e.g., by the tire pressing down on the piezoelectric component 404).

[0068] In various embodiments, the piezoelectric component 404 may include a piezoelectric material that is at least one of a crystalline and semiconducting material or a polymer and an organic material. Examples of crystalline and semiconducting materials include polyvinylidene fluoride, gallium phosphate, bismuth sodium titanate, lead zirconate titanate, quartz, berlinite (AlPO), sucrose (table sugar), Rochelle salt, topaz, minerals of the tourmaline group, lead titanate (PbTiO), langasite (LaGaSiO), gallium orthophosphate (GaPO), lithium niobate (LiNbO), lithium tantalate (LiTaO), any of the family of ceramics with perovskites, tungsten, and the like. Examples of suitable materials include stainless steel bronze, potassium niobate (KNbO), sodium tungstate (NaWO), BaNaNbO, PbKNbO, potassium sodium niobate ((K,Na)NbO) (e.g., NKN or KNN), bismuth ferrite (BiFeO), sodium niobate (NaNbO), barium titanate (BaTiO), bismuth titanate (BiTiO), sodium bismuth titanate (NaBi(TiO)), zinc blende, GaN, InN, AlN, and ZnO. Examples of polymers and organic materials include polyvinylidene fluoride (PVDF) and its copolymers, polyamides and paralyzed C, polyimides and polyvinylidene chloride (PVDC), and diphenylalanine peptide nanotubes (PNT).

[0069] In various embodiments, the substrate 402 may include at least one material such as brass, steel, spring steel (SS), carbon fiber, aluminum and its alloys, titanium and its alloys, S2 fiberglass rod, fiberglass reinforced polymer laminate (Fiberite HMS / 33), fiberglass, Kevlar laminate, carbon fiber reinforced material, aramid fiber reinforced material, fiber-reinforced plastic (FRP), copper, and alloys.

[0070] 4B is a top view 400B of the energy harvester 306, according to various embodiments. The top view 400B shows how the conductive component 406 may be connected to the piezoelectric component 404 via an interconnect 416. In other words, the interconnect 416 may be a flexible structure that connects the piezoelectric component 404 to the conductive component 406 such that the conductive component 406 may channel and offload energy generated by the piezoelectric component 404. This conductive component may be connected to other devices of the device platform to provide power to the other devices of the device platform.

[0071] The top view 400B also shows how the substrate 402 may also include locating pins 408 that secure the piezoelectric component 404 to the substrate 402. For example, the piezoelectric component 404 may include wingtip features 409 having apertures through which the locating pins 408 are configured to pass and secure the piezoelectric component to the substrate 402. Also shown is a two-dimensional curved staging surface 412 within the cavity formed by the substrate 402. Figure 4B further shows section line AA, which will be further referenced below in connection with Figures 5A and 5B.

[0072] 4C is a front view 400C of the energy harvester 306, according to various embodiments. The front view 400C illustrates how the conductive component 406 may be generally behind the substrate 402. The front view 400C also illustrates another view of how the substrate 402 may also include locating pins 408 for securing the piezoelectric component 404 to the substrate 402. For example, the piezoelectric component 404 may include a wingtip feature 409 having apertures through which the locating pins 408 are configured to pass and secure the piezoelectric component to the substrate 402. Also shown is a two-dimensional curved staging surface 412 within the cavity formed by the substrate 402.

[0073] 4D is a back view 400D of the energy harvester 306, according to various embodiments. The back view 400D illustrates that the conductive component 406 may be generally behind the substrate 402 (e.g., in the foreground in the back view 400D). The back view 400D also includes a three-dimensional curved bottom surface 410 and a physical interconnect feature 420 on the substrate 402. This physical interconnect feature 420 may be utilized to physically connect different substrates 402 together, as described in further detail below. The illustrated physical interconnect feature 420 may be a convex physical interconnect feature 420 configured to interconnect with a concave physical interconnect feature (not shown in FIG. 4D).

[0074] 4E is a bottom view 400E of the energy harvester 306, according to various embodiments. The bottom view 400E illustrates how the conductive component 406 may be generally behind the substrate 402. The bottom view 400E also includes a three-dimensionally curved bottom surface 410 and a physical interconnect feature 420 on the substrate 402. As mentioned above, this physical interconnect feature 420 may be utilized to physically connect different substrates 402 together, as described in further detail below. The illustrated physical interconnect feature 420 may be a convex physical interconnect feature 420 configured to interconnect with a concave physical interconnect feature (not shown in FIG. 4E).

[0075] FIG. 4F is a right side view 400F of the energy harvester 306, according to various embodiments. FIG. 4G also shows a left side view 400G of the energy harvester 306, according to various embodiments. The combination of both FIG. 4F and FIG. 4G may be referred to as a side view. The side view shows the conductive component 406, which may be connected to the piezoelectric component 404 via an interconnect 416. Stated another way, the interconnect 416 may be a flexible structure connecting the piezoelectric component 404 to the conductive component 406 so that the conductive component 406 may channel and offload energy generated by the piezoelectric component 404. This conductive component may be connected to other devices of the device platform to provide power to the other devices of the device platform. The side view also shows the three-dimensionally curved bottom surface 410.

[0076] FIG. 5A is a cross-sectional side view 500A of an energy harvester 306 with the piezoelectric component 404 in an unbiased state, according to various embodiments. The cross-sectional side view 500A may be across section AA shown above in FIG. 4B. Returning to FIG. 5A, the cross-sectional side view 500A shows how the conductive component 406 may be connected to the piezoelectric component 404 via an interconnect 416. Thus, the interconnect 416 may be a flexible structure connecting the piezoelectric component 404 to the conductive component 406 such that the conductive component 406 may channel and offload energy generated by the piezoelectric component 404. This conductive component may be connected to other devices of the device platform to provide power to the other devices of the device platform.

[0077] The cross-sectional side view 500A also shows how the substrate 402 can include locating pins 408 based on which the piezoelectric component 404 can be secured to the substrate 402. Also shown is a two-dimensionally curved staging surface 412 within the cavity formed by the substrate 402. A three-dimensionally curved bottom surface 410 is shown below and opposite the two-dimensionally curved staging surface 412. As shown in FIG. 5A , the two-dimensionally curved staging surface 412 is curved in two dimensions (e.g., width and height directions, but not length direction) to form a 2D convex surface. In contrast, the three-dimensional bottom surface 410 is curved in each of the width, height, and length directions. In some embodiments, the 3D bottom surface 410 has an S-shaped cross-section, as shown in FIG. 5A . The unbiased piezoelectric component 404 may not be under sufficient strain to be biased and may therefore be flat (e.g., not bent) in the unbiased state.

[0078] FIG. 5B is a cross-sectional side view 500B of the energy harvester 306 with the piezoelectric component 404 in a biased state, according to various embodiments. The cross-sectional side view 500B may be across section AA shown above in FIG. 4B. Returning to FIG. 5B, the biased piezoelectric component 404 may experience a sufficient amount of strain to bend the piezoelectric component to conform to the two-dimensionally curved staging surface 412. As described above, the piezoelectric component 404 may alternate between a biased state and an unbiased state as the rotatable component rotates. Thus, loads from the wheels or vehicle may displace the piezoelectric component and generate an electric charge (e.g., electrical energy). In some embodiments, the energy harvester can generate continuous power as the rotatable component rotates. In certain embodiments, this energy may be in the form of an alternating current (AC) signal, which can be rectified into a direct current (DC) signal. In other words, the bending strain experienced by the piezoelectric component may generate energy (e.g., an alternating current (AC) voltage) having a frequency proportional to the rotational frequency of the wheel. In some embodiments, the AC signal is rectified by a rectifier circuit included within the sensor 304 .

[0079] FIG. 6 is a perspective view 600 of an integrated energy harvester 606, according to various embodiments. The integrated energy harvester 606 can be disposed along the periphery of the rotatable component 608 (e.g., a rim) without the need for a substrate. Stated another way, the integrated energy harvester 606 can be integrated within the rotatable component 608, and thus there can be no separate physical substrate structure. The rotatable component 608 can include a curved staging surface 612 (e.g., a microcavity or depression formed on the rotatable component 608) formed thereon. In some embodiments, the curved staging surface 612 is curved in only two dimensions (e.g., height and width, but not length) to form a two-dimensional convex surface 612. The piezoelectric component 614 can deform under strain to conform to the two-dimensionally curved staging surface 612. Additionally, this two-dimensionally curved staging surface 612 can differ from the remainder of the rotatable component 608, which can have a three-dimensionally curved surface. The rectangular piezoelectric component 614 may be configured to bend within the two-dimensionally curved staging surface 612. In some embodiments, the two-dimensionally curved staging surface 612 may be referred to as a convex surface. Thus, the two-dimensionally curved staging surface 612 may include (e.g., be convex) a convex surface to which a piezoelectric component 604 having a straight (e.g., non-curved or flat) shape or surface may be more easily and securely attached compared to a three-dimensionally curved surface. The piezoelectric component 604 may be bent relative to the convex, two-dimensionally curved staging surface 612 to generate a compressive bending strain on the piezoelectric component 614. In other words, the piezoelectric component 614 may be subjected to a strain that causes the piezoelectric component to bend to conform to the convex, two-dimensionally curved staging surface 612 (e.g., bend relative to the convex surface) and generate an electric charge (e.g., via mechanical deformation of the piezoelectric material layer). Thus, the convex two-dimensional curved staging surface 612 of the rotatable component 608 may be structured to allow distortion (e.g., relative movement / deflection) of the piezoelectric component 614 when positioned between the tire of a wheel and the rotatable component 608 (e.g., by the tire pressing down on the piezoelectric component 614).

[0080] The integrated energy harvester 606 may include a conductive component 616 configured to channel and offload energy generated by the piezoelectric component 614. This conductive component may be connected to the leads of a rechargeable battery housed within the device platform's sensor housing 304 ( FIGS. 3A and 3B ) to power the sensor(s) within the sensor housing 304. In some embodiments, this conductive component 616 may be constructed from a flexible conductive material such as brass or copper. The integrated energy harvester 606 may also include locating pins (not shown) for securing the piezoelectric component 614 to the convex, two-dimensionally curved staging surface 612 of the rotatable component 608.

[0081] In some embodiments, the piezoelectric component 614 may be formed of different types of layers. For example, one type of layer of the piezoelectric component 614 may be a load-bearing layer. This load-bearing layer may be, for example, a steel plate with sufficient load flexibility to hold the piezoelectric component together. Another type of layer of the piezoelectric component may be a piezoelectric material layer that may be configured to generate an electric charge through mechanical deformation. Yet another type of layer of the piezoelectric component may be an electrode layer for harvesting electrical energy (e.g., an electric charge) from the piezoelectric material layer.

[0082] In some embodiments, the load support layer, when bonded to the piezoelectric ceramic material of the piezoelectric material layer, ensures that the piezoelectric ceramic material does not crack or buckle under the compressive and / or tensile stresses imposed on the piezoelectric ceramic material during bending. In various embodiments, the electrode layer may be electrically bonded to other layers of the piezoelectric component (e.g., the load support layer and / or the piezoelectric material layer). The load support layer may also be electrically and / or mechanically bonded to the piezoelectric material layer. The assembly of all layers of the piezoelectric component may form the piezoelectric component (which may be referred to in some embodiments as a piezoelectric electrode assembly). In further embodiments, the piezoelectric component may be encapsulated in a protective coating, such as a heat-shrinkable film or polymer, to protect the piezoelectric component from environmental degradation.

[0083] 7A illustrates an example of a piezoelectric component 730 according to one embodiment of the present disclosure. In this example, the piezoelectric component 730 includes an electrode layer 732, a piezoelectric material layer 734, a conductive bonding layer 736, and a load support layer 738. Additional layers may also be implemented but are not shown for ease of illustration.

[0084] The conductive bonding layer 736 may be referred to as a bonding layer used to bond the piezoelectric material layer 734 and the load support layer 738. In one example, the conductive bonding layer 736 includes a metal powder and a resin. In another example, the conductive bonding layer 736 is vertically above and in direct contact with the load support layer 738, the piezoelectric material layer 734 is vertically above the conductive bonding layer 736, and the piezoelectric material layer 734 is horizontally surrounded by the electrode layer 732. In one example, the load support layer 738 includes a fiber-reinforced composite material having a high modulus of elasticity, and the conductive bonding layer 736 is used to transfer the effects of the high modulus of elasticity from the fiber-reinforced composite material to the piezoelectric material layer 734. In this way, when the piezoelectric component 730 deforms under mechanical strain, the piezoelectric component 730 may “bounce back” to its original shape more quickly and more frequently (i.e., over more cycles compared to when steel is used for the load support layer 738). As a result, power can be generated in the energy harvester 306 more efficiently and over more cycles.

[0085] In some embodiments, the load support layer 738 includes a fiber-reinforced composite material and a surface layer. In one example, the surface layer is a resin layer. In another example, the surface layer is between the fiber-reinforced composite material and the conductive bonding layer 736, when the conductive bonding layer 736 is vertically above and in direct contact with the load support layer 738. In some embodiments, the surface layer is removed from the load support layer 738 so that the fiber-reinforced composite material in the load support layer 738 is exposed and in direct contact with the conductive bonding layer 736. In this manner, the modulus of elasticity of the fiber-reinforced composite material after the surface layer is removed can be higher than the modulus of elasticity of the fiber-reinforced composite material before the surface layer is removed. In yet another example, the surface layer is removed using a mechanical etching process or a laser etching process.

[0086] FIG. 7B shows top views of CFC material 742 with a coated surface layer and CFC material 744 with the surface layer removed. In some embodiments, the coated surface layer of CFC material 742 is a resin layer. Removing the coated surface layer of CFC material 742 can increase the elastic modulus. Thus, CFC material 744 with the surface layer removed can exhibit a higher elastic modulus. In this manner, when CFC material 744 is directly connected to a conductive bonding layer that is directly connected to the piezoelectric layer, the piezoelectric layer can quickly return to its original shape after being deformed under mechanical strain. Additionally, removing the surface (resin) layer of CFC material 744 can provide better adhesion and bonding between load-bearing layer 738 and conductive bonding layer 736.

[0087] 8A illustrates yet another example of a piezoelectric component 800 according to one embodiment of the present disclosure. In this example, the piezoelectric component 800 includes two electrode layers 802 and 808, a piezoelectric material layer 806, two electrically conductive bonding layers 804 and 810, a load support layer 812, and an electrical wire 814 connected to the electrode layer 808. Additional layers may also be implemented but are not shown for ease of illustration. The functions of the piezoelectric material layer 806, the electrode layer 808, the electrically conductive bonding layer 810, and the load support layer 812 have been described above with reference to FIG. 7B and will not be repeated here. The additional layers included in this embodiment are the electrode layer 802, the electrically conductive bonding layer 804, and the electrical wire 814, which will now be described in detail.

[0088] Electrode layer 802 may be used to indirectly contact piezoelectric material layer 806 (e.g., via conductive bonding layer 804) to harvest charge from piezoelectric material layer 806. In some embodiments, electrode layers 802 and 808 may represent different circuits with different potentials such that a potential difference exists between electrode layers 802 and 808. Thus, the potential difference between electrode layers 802 and 808 may be used to power devices of the smart wheel sensor system via electrical wires 814.

[0089] The conductive bonding layer 804 can be used to bond the piezoelectric material layer 806 and the electrode layer 802. In some embodiments, the conductive bonding layer 804 includes a metal powder and a resin and is vertically above and in direct contact with the piezoelectric material layer 806.

[0090] 8B shows a cross-sectional view of a piezoelectric component 800 according to one embodiment of the present disclosure. The functions of electrode layers 802 and 808, piezoelectric material layer 806, conductive bonding layers 804 and 810, and load support layer 812 have been described above with reference to FIG. 8A and will not be repeated here. In some embodiments, piezoelectric material layer 806 is surrounded by electrode layer 808 with a gap 814 between the inner periphery of electrode layer 808 and the outer periphery of piezoelectric material layer 806 to prevent shorting between layers 806 and 808. In some embodiments, gap 814 is 100 μm or greater.

[0091] 9A illustrates yet another example of a piezoelectric component 900 in accordance with one embodiment of the present disclosure. In this example, the piezoelectric component 900 comprises an electrode layer 902, a piezoelectric material layer 904, a metal layer 906, a conductive bonding layer 908, and a load support layer 910. Additional layers may also be implemented but are not shown for ease of illustration. The functions of the electrode layer 902, the piezoelectric material layer 904, the conductive bonding layer 908, and the load support layer 910 have been described above with reference to FIG. 7B and will not be repeated here. The additional layer included in this embodiment is the metal layer 906, which will now be described in detail.

[0092] The metal layer 906 may be referred to as a metallic layer used to improve electrical conductivity between the piezoelectric material layer 904 and the conductive bonding layer 908. Examples of the metal layer 906 include a silver (Ag) metal layer, a copper (Cu) metal layer, an aluminum (Al) metal layer, a gold (Au) metal layer, and / or any other type of metal layer.

[0093] In one example, the metal layer 906 has a thickness in the range of 1.0 to 20 μm. In another example, the metal layer 906 has a thickness in the range of 3.0 to 10 μm. In yet another example, the piezoelectric material layer 904 has a thickness in the range of 30 to 500 μm. In yet another example, the piezoelectric material layer 904 has a thickness in the range of 50 to 200 μm. In yet another example, the conductive bonding layer 908 has a thickness in the range of 1.0 to 100 μm. In yet another example, the conductive bonding layer 908 has a thickness in the range of 5.0 to 50 μm. In some embodiments, the conductive bonding layer 908 includes a metal powder and a resin. Examples of the metal powder in the conductive bonding layer 908 include Ag metal powder, Cu metal powder, Al metal powder, Au metal powder, and / or any other type of metal powder.

[0094] In some embodiments, the conductive bonding layer 908 is vertically above and in direct contact with the load support layer 910, the metal layer 906 is vertically above and in direct contact with the conductive bonding layer 908, the piezoelectric material layer 904 and the electrode layer 902 are vertically above and in direct contact with the metal layer 906, and the piezoelectric material layer 904 is horizontally surrounded by and in direct contact with the electrode layer 902.

[0095] FIG. 9B illustrates a microscopic cross-sectional view of a piezoelectric material layer 904, a metal layer 906, a conductive bonding layer 908, and a load-bearing layer 910 in a piezoelectric component 900, according to one embodiment of the present disclosure. In some embodiments, as shown in FIG. 9B , the piezoelectric material layer 904 includes voids 912a-n as shown. The voids 912a-n can be created as a result of the sintering process, particularly during the cooling process following the sintering process. In some embodiments, the metal layer 906 and the piezoelectric material layer 904 are not sintered simultaneously. In some examples, the sintering process is liquid phase sintering, which results in residual stress after the sintering process. The voids 912a-n can arise to relieve the residual stress after the sintering process. Residual stress in a material can be said to be a physical quantity that represents the internal force that adjacent particles of the material exert on each other. The reduction in residual stress in the piezoelectric material layer 904 due to the voids 912a-n makes the piezoelectric material layer 904 less brittle. Thus, the piezoelectric material layer 904 may be less susceptible to fatigue cracking and delamination due to the presence of the voids 912a-n.

[0096] In some examples, the amount of voids in piezoelectric material layer 904 is characterized by a porosity value. The porosity value in a material may be referred to as the percentage of void space in the material. In some embodiments, the porosity value is calculated as the ratio of the volume of voids in the material divided by the total volume of the material. In one example, the porosity value of piezoelectric material layer 904 is in the range of 97% to 99.9%. In another example, the porosity value of piezoelectric material layer 904 is in the range of 98% to 99.5%.

[0097] 10A illustrates yet another example of a piezoelectric component 1000 in accordance with one embodiment of the present disclosure. In this example, the piezoelectric component 1000 comprises an electrode layer 1002, a piezoelectric material layer 1004, an interface layer 1006, a metal layer 1008, a conductive bonding layer 1010, and a load support layer 1012. The functions of the electrode layer 1002, the piezoelectric material layer 1004, the metal layer 1008, the conductive bonding layer 1010, and the load support layer 1012 have been described above with reference to FIG. 9A and will not be repeated here. An additional layer included in this embodiment is the interface layer 1006, which will now be described in detail.

[0098] The interface layer 1006 may be said to be a layer formed between the piezoelectric material layer 1004 and the metal layer 1008 as a result of a sintering process that forms a bond between the piezoelectric material layer 1004 and the metal layer 1008. In some embodiments, the interface layer 1006 is formed to further strengthen the bond between the piezoelectric material layer 1004 and the metal layer 1008.

[0099] In some embodiments, the material of the interface layer 1006 is determined based on the material of the piezoelectric material layer 1004. In one example, the piezoelectric material layer 1004 includes a bismuth (Bi)-based piezoelectric material, and as a result, the interface layer 1006 includes a Bi-based glass frit or a Bi-based paste. In another example, the piezoelectric material layer 1004 includes a lead (Pb)-based piezoelectric material, and as a result, the interface layer 1006 includes lead oxide. In some embodiments, the interface layer 1006 includes amorphous lead oxide or amorphous bismuth oxide. In some other embodiments, the interface layer 1006 includes a low-melting-point material, such as lead (IV) oxide (PbO), which has a melting point of 290° C.

[0100] 10B shows an example cross-sectional scanning electron microscope (SEM) image of the piezoelectric material layer 1004, the interface layer 1006, the metal layer 1008, the conductive bonding layer 1010, and the voids 1014a-n in the piezoelectric component 1000, in accordance with one embodiment of the present disclosure. The functions of the piezoelectric material layer 1004, the interface layer 1006, the metal layer 1008, the conductive bonding layer 1010, and the voids 1014a-n have been described above with reference to FIGS. 9B and 10A and will not be repeated here. In some embodiments, the voids 1014a-n are formed as a result of the sintering process, particularly during the cooling process following the sintering process. In some examples, the voids 1014a-n are formed in the interface layer 1006 to reduce internal stress at the interface between the piezoelectric material layer 1004, the interface layer 1006, and the metal layer 1008. In some examples, the sintering process is liquid phase sintering, which results in residual stress after the sintering process. The voids 1014a-n may occur to relieve residual stress after the sintering process.

[0101] 11A illustrates yet another example of a piezoelectric component 1100 according to one embodiment of the present disclosure. In this example, the piezoelectric component 1100 includes two electrode layers 1102 and 1108, two conductive bonding layers 1104 and 1114, two metal layers 1106 and 1112, a piezoelectric material layer 1110, and a load support layer 1116. The functions of the electrode layers 1102 and 1108, the conductive bonding layers 1104 and 1114, the metal layer 1112, the piezoelectric material layer 1110, and the load support layer 1116 have been described above with reference to FIGS. 8A and 9A and will not be repeated here. An additional layer included in this embodiment is the metal layer 1106. The metal layer 1106 may be used to improve electrical conductivity between the piezoelectric material layer 1110 and the conductive bonding layer 1104.

[0102] 11B illustrates yet another example of a piezoelectric component 1120 according to one embodiment of the present disclosure. In this example, the piezoelectric component 1120 includes two electrode layers 1122 and 1130, two conductive bonding layers 1124 and 1138, two metal layers 1126 and 1136, two interface layers 1128 and 1134, a piezoelectric material layer 1132, and a load-supporting layer 1140. The functions of the electrode layers 1122 and 1130, the conductive bonding layers 1124 and 1138, the metal layers 1126 and 1136, the interface layer 1134, the piezoelectric material layer 1132, and the load-supporting layer 1140 have been described above with reference to FIGS. 10A and 11A and will not be repeated here. An additional layer included in this embodiment is an interface layer 1128. The interface layer 1128 may be formed to strengthen the bond between the piezoelectric material layer 1132 and the metal layer 1126. The material of the interface layer 1128 may be determined based on the material of the piezoelectric material layer 1132 .

[0103] 11C shows another example of a microscopic cross-sectional view of a piezoelectric component 1150 according to an embodiment of the present disclosure. In some embodiments, the piezoelectric component 1150 comprises a conductive bonding layer 1152, a metal layer 1154, a piezoelectric material layer 1156, a metal layer 1158, a conductive bonding layer 1160, a load support layer 1162, and voids 1164a-n. The functions of the conductive bonding layer 1152, the metal layer 1154, the piezoelectric material layer 1156, the metal layer 1158, the conductive bonding layer 1160, the load support layer 1162, and the voids 1164a-n have been described above with reference to FIGS. 9B and 10B and will not be repeated here.

[0104] In some embodiments, the load-bearing layer 1140 may include a fiber-reinforced composite material. Examples of fiber-reinforced composite materials include carbon fiber composite (CFC) materials, glass fiber composite materials, carbon nanotube-reinforced composite materials, graphene-reinforced composite materials, and ceramic matrix composite materials. In some examples, the fiber-reinforced composite material includes a CFC material. In one example, the CFC material has a checkerboard-like interwoven structure. In another example, the CFC material has a quasi-isotropic structure. A quasi-isotropic structure may be described as a structure made of woven carbon fiber with plies oriented at various angles.

[0105] In some embodiments, a CFC structure provides a stiffer material (higher Young's modulus) that results in higher strain generation for the same amount of stress, thus imparting higher strain to the piezoelectric material layer 1132 in the presence of the interface layer 1134. Thus, the energy harvester 306 may generate higher charge output and higher power using a checkerboard-woven CFC structure or a quasi-isotropic CFC structure. For example, referring to FIG. 12 , improved power generation using a carbon fiber composite material is shown compared to a steel material. As can be seen, a CFC voltage generation timing diagram 1224 and a steel voltage generation timing diagram 1226 are shown, with the x-axis representing time in milliseconds and the y-axis representing voltage values ​​generated in the energy harvester 306. In some examples, a load support layer 1140 having a steel material generates a peak-to-peak voltage value of 55 volts, while a load support layer 1140 having a CFC material generates a peak-to-peak voltage value of 85 volts, which is approximately 50% higher than the peak-to-peak voltage value generated by the steel material.

[0106] In some embodiments, the particular microstructure in the checkerboard-woven and quasi-isotropic CFC structures also provides a higher modulus of elasticity, higher tensile strength, higher chemical resistance, higher temperature resistance, lower thermal expansion, and lower weight than those provided by steel embodiments of the load-bearing layer 1140. Examples of modulus of elasticity include Young's modulus, bulk modulus, and shear modulus. In some embodiments, the quasi-isotropic CFC structure provides higher stiffness than the checkerboard-woven CFC structure and therefore generates more strain for the same amount of bending of the structure. In some embodiments, the appropriate selection of the laminated thermosetting epoxy may further increase the stiffness of the checkerboard-woven and quasi-isotropic CFC structures, thus making them more robust to high temperatures.

[0107] In one example, the CFC material of the load support layer 1140 has a resistance of about 1500 kg / m 3 ~About 2000kg / m 3The CFC material of the load support layer 1140 has a density in the range of about 1000 MPa to about 4000 MPa, a tensile strength in the range of about 300 GPa to about 500 GPa, and a Young's modulus in the range of about 300 GPa to about 500 GPa. The higher Young's modulus of the CFC material of the load support layer 1140 may generate higher mechanical strains applied to the piezoelectric components to prevent cracking or degradation due to tensile and / or compressive forces acting on the piezoelectric components. Thus, more deformation in the piezoelectric components may be generated throughout the life of the integrated energy harvester.

[0108] 13 is a flowchart of an energy harvester process 1800, according to various embodiments. Process 1800 may be implemented in a smart wheel sensor system integrating an energy harvester and at least one device configured to be powered by the energy harvester, as introduced above. Note that process 1800 is merely an example and is not intended to limit the present disclosure. Thus, it is understood that additional operations (e.g., blocks) may be provided before, during, and after process 1800 of FIG. 13, that certain operations may be omitted, that certain operations may be performed simultaneously with other operations, and that some other operations may only be briefly described herein.

[0109] In block 1802, a wheel may be moved (e.g., rotated) under a load (e.g., the load of the wheel itself or of an object (e.g., a vehicle) driving the wheel). As described above, the wheel may be a smart wheel or a smart wheel sensor system that integrates an energy harvester and at least one device configured to be powered by the energy harvester. The energy harvester includes a piezoelectric component disposed on a curved staging surface. The curved staging surface may be part of a cavity such that the piezoelectric component may bend into the cavity when strained (e.g., when biased). The curved staging surface may either be formed directly as part of the wheel or may be formed on a substrate attached to a portion of the wheel to facilitate application of strain to the piezoelectric component.

[0110] The energy harvester may further include a piezoelectric component including a piezoelectric material layer and at least one electrode layer. The piezoelectric component may also be connected to an interconnect and a conductive component. The piezoelectric material layer may generate energy when mechanically deformed. The electrode layer may capture the energy generated by the piezoelectric material layer. The electrode layer may be connected to the conductive component via the interconnect. The interconnect may be a flexible structure connecting the piezoelectric component to the conductive component such that the conductive component may channel and offload the energy generated by the piezoelectric component. The conductive component may be connected to other devices of the device platform (e.g., an energy storage medium or a sensor of a smart wheel sensor system) to provide power to the other devices of the device platform.

[0111] In block 1804, the piezoelectric component of the energy harvester may deform (e.g., mechanically deform) to generate energy resulting from a compressive force due to the rotation of a wheel (e.g., a vehicle acting on a bead area of ​​a tire attached to the rotatable component). Stated another way, the piezoelectric component may capture the kinetic energy of a vehicle moving in response to the rotation of the rotatable component. Thus, the piezoelectric component may generate energy when a mechanical stress is applied to the piezoelectric component. For example, this energy may be in the form of an alternating current (AC) signal, which can be rectified to a direct current (DC) signal. Stated another way, the bending strain experienced by the piezoelectric component may generate energy (e.g., an AC voltage) having a frequency proportional to the rotational frequency of the wheel.

[0112] At block 1806, the energy generated by the energy harvester may be transferred to a device of the smart wheel sensor system. As described above, this energy may be transferred to the device by, for example, a conductive component. The conductive component may be any type of conductor configured to transfer the energy generated by the energy harvester, such as a wire, ribbon, or pin made of a conductive material to transfer energy from the energy harvester to the device.

[0113] At block 1808, a device connected to the conductive component may be powered by energy generated by the energy harvester. This device may be, for example, an energy storage medium or a sensor of the smart wheel sensor system. Thus, the energy harvester may be part of the smart wheel sensor system for providing power to at least one energy storage medium or sensor of the smart wheel sensor system. The smart wheel sensor system may include multiple types of sensors, each configured to collect different types of smart wheel sensor system data. For example, the smart wheel sensor system may include a height sensor configured to generate barometric pressure sensor data and / or tire inner surface deflection, an acoustic sensor configured to generate acoustic sensor data, an image sensor configured to generate image sensor data, a gas sensor configured to generate gas sensor data, a magnetic sensor configured to generate magnetic sensor data, an accelerometer sensor configured to generate acceleration sensor data, a gyroscope sensor configured to generate gyroscope sensor data, and a humidity sensor configured to generate humidity sensor data, as described above.

[0114] 14 illustrates an exemplary method 2000 of fabricating a piezoelectric component, according to one embodiment of the present disclosure. The operations of method 2000 presented below are intended to be exemplary. In some embodiments, method 2000 may be accomplished with one or more additional operations not described and / or without one or more of the operations described. Additionally, the order in which the operations of method 2000 are shown in FIG. 14 and described below is not intended to be limiting.

[0115] In step 2002, a load-bearing layer, a conductive bonding layer, a piezoelectric layer including a piezoelectric material, and an electrode layer are formed. In one example, the load-bearing layer includes a fiber-reinforced composite material. In some embodiments, the fiber-reinforced composite material includes a CFC material, which has a checkerboard-like interwoven structure or a quasi-isotropic structure, and the amount and orientation of fibers in the CFC material can be configured during manufacturing to provide a higher modulus of elasticity. In some embodiments, the conductive bonding layer includes a metal powder and a resin used to transfer the effects caused by the high modulus of elasticity of the CFC material from the load-bearing layer to the piezoelectric material layer.

[0116] The piezoelectric body of the piezoelectric layer is sintered in step 2004. In some embodiments, the piezoelectric body is sintered by first forming a lead zirconate titanate (PZT) mold containing polyvinylpyrrolidinone (PVP) as a binder using a dry pressing process, and then sintering the PZT mold at a temperature between 1100°C and 1250°C for 2 to 24 hours.

[0117] In step 2006, a compound paste is applied onto the piezoelectric body to form an interface layer. In some embodiments, the compound paste is applied using a dip-coating process or a screen-printing process. In some examples, the material of the compound paste used to form the interface layer 1106 is determined based on the material of the piezoelectric body, as described above. In one example, the piezoelectric body includes a Bi-based piezoelectric material, and therefore the interface layer is configured to include a Bi-based glass frit or a Bi-based paste. In another example, the piezoelectric body includes a Pb-based piezoelectric material, and therefore the compound paste is configured to include lead monoxide (PbO), lead acetate (Pb(CHCOO)), or a Pb-based glass frit, with the mass fraction of the Pb-based glass frit in the Pb compound paste ranging from about 3% to about 10%, forming voids in the interface layer. In some embodiments, the voids in the interface layer reduce stress levels within the interface layer, making the piezoelectric component less brittle and less susceptible to fatigue cracking and delamination.

[0118] The piezoelectric body is dried in step 2008. In some embodiments, the piezoelectric body is dried at a temperature between about 50° C. and about 80° C. for a duration of 1 to 30 hours.

[0119] In step 2010, a metal paste is applied onto the compound paste to form a metal layer. In some embodiments, the metal paste includes a silver (Ag) paste and is applied onto the surface of the compound paste applied onto the piezoelectric body. In some examples, the metal paste also includes a Pb-based glass frit.

[0120] The metal layer formed by the metal paste, the compound paste, and the piezoelectric body are sintered in step 2012. In some embodiments, the metal layer, the compound paste, and the piezoelectric body are sintered at a temperature of about 300° C. to about 800° C. for a duration of 0.5 to 4 hours.

[0121] In step 2014, a surface layer of the fiber-reinforced composite material in the load-bearing layer is removed. In some examples, the surface layer of CFC material comprises a resin layer. In some embodiments, the surface layer is removed so that the CFC material is exposed on the surface of the load-bearing layer. The surface layer may be removed by a mechanical etching process or a laser etching process. Examples of mechanical etching processes used to remove the surface layer include chemical-mechanical polishing, a milling process, a lathing process, and water-resistant sandpaper polishing.

[0122] In step 2016, the load support layer, the conductive bonding layer, the piezoelectric layer including the metal layer and the interface layer, and the electrode layer are laminated in a lamination process. In some embodiments, the lamination process is carried out by simultaneously laminating the load support layer, the conductive bonding layer, the piezoelectric layer including the metal layer and the interface layer, and the electrode layer using a hydraulic heat press at a pressure of about 0.1-2.0 MPa and a temperature of about 120-170°C for a duration of about 5-100 seconds. In some examples, the laminated layers are passed through a vacuum oven and cured at a temperature of about 120-170°C for a duration of about 15-120 seconds. In some embodiments, a conductive bonding layer is used to bond the load support layer, the piezoelectric layer, and the electrode layer.

[0123] While various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only, and not by way of limitation. Similarly, various figures may depict example structures or configurations provided to enable those skilled in the art to understand exemplary features and functionality of the present invention. However, those skilled in the art will understand that the present invention is not limited to the example structures or configurations shown, but can be implemented using various alternative structures and configurations. In addition, as will be understood by those skilled in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described example embodiments.

[0124] It will also be understood that any reference to elements herein using a designation such as "first," "second," etc., generally does not limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient means of distinguishing between two or more elements or entities of elements. Thus, a reference to a first and a second element does not imply that only two elements can be used or that the first element must precede the second element in any manner.

[0125] Additionally, those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, and symbols that may be referenced in the above description may be represented by, for example, voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0126] Those skilled in the art will further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods, and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., digital implementations, analog implementations, or a combination of the two, which may be designed using source coding or some other technique), various forms of programs or design code incorporating instructions (sometimes referred to herein for convenience as “software” or “software modules”), or a combination of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these techniques, depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0127] Furthermore, those skilled in the art will appreciate that the various example logical blocks, modules, devices, components, and circuits described herein can be implemented in or performed by integrated circuits (ICs), which can include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logical blocks, modules, and circuits can further include an antenna and / or a transceiver for communicating with various components within a network or device. A general-purpose processor can be a microprocessor, but alternatively, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration for performing the functions described herein.

[0128] If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that can enable a computer program or code to be transferred from one place to another. A storage medium can be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0129] As used herein, the term "module" refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purposes of explanation, various modules are described as separate modules. However, one skilled in the art will appreciate that two or more modules may be combined to form a single module that performs the associated functions according to embodiments of the present invention.

[0130] Additionally, embodiments of the invention may use memory or other storage devices, as well as communication components. It will be appreciated that, for clarity, the above description has described embodiments of the invention with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements, or domains may be used without departing from the invention. For example, functionality shown to be performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Accordingly, references to specific functional units do not indicate a strict logical or physical structure or organization, but merely to suitable means for providing the described functionality.

[0131] Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the following claims.

Claims

1. a piezoelectric component configured to generate energy in response to mechanical strain applied to said piezoelectric component; An energy harvesting module comprising: the piezoelectric component is configured to deform while subjected to the mechanical strain; the piezoelectric component comprising a piezoelectric material layer, one or more electrically conductive bonding layers, a load-bearing layer, and one or more electrode layers, the load-bearing layer comprising a fiber-reinforced composite material; Energy harvesting module.

2. the one or more electrode layers include a first electrode layer, the one or more conductive bonding layers include a first conductive bonding layer; the first conductive bonding layer is vertically above and in direct contact with the load support layer; the piezoelectric material layer is vertically above and in direct contact with the first conductive bonding layer, and the piezoelectric material layer is horizontally surrounded by the first electrode layer; The energy harvesting module of claim 1 .

3. 2. The energy harvesting module of claim 1, wherein the fiber-reinforced composite material comprises at least one of a carbon fiber composite material, a glass fiber composite material, a carbon nanotube-reinforced composite material, a graphene-reinforced composite material, and a ceramic matrix composite material.

4. 3. The energy harvesting module of claim 2, wherein the fiber-reinforced composite material is in direct contact with the first electrically conductive bonding layer by removing a surface layer of the fiber-reinforced composite material, and removing the surface layer comprises a mechanical etching process, an ablation process, a chemical etching process, or a laser etching process.

5. 4. The energy harvesting module of claim 3, wherein the fiber-reinforced composite material has an elastic modulus, and the elastic modulus after the surface layer is removed is higher than the elastic modulus before the surface layer is removed.

6. the one or more electrode layers include a second electrode layer, and the one or more conductive bonding layers include a second conductive bonding layer; the second conductive bonding layer is vertically above and in direct contact with the piezoelectric material layer; the second electrode layer is vertically above and in direct contact with the second conductive bonding layer; The energy harvesting module of claim 2 .

7. The energy harvesting module of claim 1 , wherein the one or more conductive bonding layers comprise a metal powder and a resin.

8. a piezoelectric component configured to generate energy in response to mechanical strain applied to said piezoelectric component; An energy harvesting module comprising: the piezoelectric component is configured to deform while subjected to the mechanical strain; the piezoelectric component comprises a piezoelectric material layer, one or more electrically conductive bonding layers, a load-bearing layer, one or more electrode layers, and one or more metal layers, the load-bearing layer comprising a fiber-reinforced composite material; Energy harvesting module.

9. the one or more metal layers include a first metal layer, the one or more electrode layers include a first electrode layer, and the one or more conductive bonding layers include a first conductive bonding layer; the first conductive bonding layer is vertically above and in direct contact with the load support layer; the first metal layer is vertically above and in direct contact with the first conductive bonding layer, and the first metal layer is electrically connected to the first conductive bonding layer; the piezoelectric material layer is vertically above the first metal layer and is horizontally surrounded by the first electrode layer; 9. The energy harvesting module of claim 8.

10. the piezoelectric component further comprising one or more interface layers, the one or more interface layers including a first interface layer; the first interfacial layer is vertically above and in direct contact with the first metal layer; the piezoelectric material layer is vertically above and in direct contact with the first interface layer; 10. The energy harvesting module of claim 9.

11. 10. The energy harvesting module of claim 9, wherein the one or more metal layers include a second metal layer, the one or more electrode layers include a second electrode layer, the one or more conductive bonding layers include a second conductive bonding layer, and the second metal layer is vertically above the piezoelectric material layer.

12. 12. The energy harvesting module of claim 11, wherein the second conductive bonding layer is vertically above the second metal layer and in direct contact with the second metal layer, and the second conductive bonding layer is electrically connected to the second metal layer.

13. The energy harvesting module of claim 8 , wherein the one or more metal layers include a silver (Ag) metal layer, a copper (Cu) metal layer, an aluminum (Al) metal layer, or a gold (Au) metal layer.

14. The energy harvesting module of claim 12 , wherein the one or more interface layers comprise amorphous lead oxide or amorphous bismuth oxide.

15. The energy harvesting module of claim 14 , wherein the one or more interface layers include an air gap.

16. forming a load-bearing layer comprising a fiber-reinforced composite material, the fiber-reinforced composite material including a surface layer, the surface layer including a resin layer; forming a conductive bonding layer; forming a piezoelectric material layer including a piezoelectric body; forming an electrode layer; sintering the piezoelectric body of the piezoelectric material layer; applying a compound paste onto the piezoelectric body to form an interface layer; drying the compound paste on the piezoelectric body; applying a metal paste onto the compound paste to form a metal layer; sintering the metal layer and the compound paste; A method comprising:

17. 17. The method of claim 16, further comprising removing the surface layer of the fiber-reinforced composite material by a mechanical etching process, an ablation process, a chemical etching process, or a laser etching process.

18. laminating the conductive adhesive layer on the load support layer; laminating the piezoelectric material layer on the conductive bonding layer; depositing the electrode layer on the piezoelectric material layer; 20. The method of claim 17, further comprising:

19. When the piezoelectric body contains a lead (Pb)-based piezoelectric material, the compound paste may contain lead monoxide (PbO), lead acetate (Pb(CH ３ COO) ２ ), or Pb-based glass frit, wherein the mass fraction of the Pb-based glass frit in the compound paste is in the range of about 3% to about 10%, and voids are formed in the interface layer; 17. The method of claim 16.

20. When the piezoelectric body contains a bismuth (Bi)-based piezoelectric material, the compound paste contains a Bi-based glass frit or a Bi-based paste.

17. The method of claim 16.

Images