Temperature sensor and application in wireless charging

Abstract

Some embodiments of the present disclosure relate to systems and methods for sensing temperature using a bimetallic thermocouple embedded in a printed circuit board (PCB). In some embodiments, the PCB includes a thermocouple embedded in the PCB. The thermocouple includes a first metal trace and a second metal trace. The thermocouple is configured to generate a voltage indicative of a temperature associated with the PCB. In some embodiments, a thermocouple or thermistor is used by a wireless charging pad to sense temperature.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 487,554, filed on February 28, 2023, entitled “TEMPERATURE SENSING IN WIRELESSCHARGING,” the technical disclosure of which is incorporated herein by reference in its entirety and for all purposes. Technical Field

[0003] The present disclosure relates to systems and methods for temperature sensing. More particularly, embodiments of the present disclosure relate to temperature sensors and circuits or components for sensing temperature. Background Art

[0004] A variety of temperature sensors can be used by a device or system to detect one or more temperatures associated with the device or system. For example, bimetallic thermocouples, which generate a voltage signal between two metal traces, are used in various devices to detect temperature. Temperature sensing can be implemented in a variety of applications. Summary of the Invention

[0005] The systems, methods, and devices of the present disclosure each have several innovative embodiments, no single one of which is solely responsible for all of the desirable properties disclosed herein. The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below.

[0006] In some aspects, the technology described herein relates to a printed circuit board (PCB) comprising: a thermocouple embedded in the PCB, the thermocouple comprising a first metal trace and a second metal trace, wherein the thermocouple is configured to generate a voltage indicative of a temperature.

[0007] In some aspects, the technology described herein relates to a PCB wherein the first metal trace comprises copper, and wherein the second metal trace comprises constantan.

[0008] In some aspects, the technology described herein relates to a PCB further comprising a dielectric layer positioned between a first metal trace and a second metal trace.

[0009] In some aspects, the technology described herein relates to a PCB further comprising a second dielectric layer and a third dielectric layer, wherein the first metal trace and the second metal trace are positioned between the second dielectric layer and the third dielectric layer.

[0010] In some aspects, the technology described herein relates to a PCB, further comprising a second thermocouple embedded in the PCB, the second thermocouple configured to generate a second voltage indicative of a second temperature, wherein the temperature and the second temperature are associated with different locations.

[0011] In some aspects, the technology described herein relates to a PCB in which a first metal trace of a second thermocouple has an end shorted to the first metal trace of the thermocouple, and in which a second metal trace of the second thermocouple has an end shorted to the second metal trace of the thermocouple.

[0012] In some aspects, the technology described herein relates to a PCB in which a thermocouple and a second thermocouple are arranged in parallel.

[0013] In some aspects, the technology described herein relates to a PCB in which a thermocouple and a second thermocouple are connected to the same thermal wire.

[0014] In some aspects, the technology described herein relates to a PCB further comprising: a surface layer positioned above the thermocouple, wherein the surface layer includes a coil configured to generate an electromagnetic field for wireless charging.

[0015] In some aspects, the technology described herein involves a PCB that also includes 100 additional embedded thermocouples.

[0016] In some aspects, the technology described herein relates to a wireless charging pad that includes a PCB.

[0017] In some aspects, the technology described herein relates to a PCB assembly that includes a PCB and processing circuitry configured to determine temperature based on voltage.

[0018] In some aspects, the technology described herein relates to a charging pad comprising: a coil configured to generate an electromagnetic field for wireless charging; one or more sensors configured to generate one or more sensing signals for thermal detection of an object positioned above the coil; and processing circuitry in communication with the one or more sensors, the processing circuitry configured to control operation of the charging pad based at least on the one or more sensing signals.

[0019] In some aspects, the technology described herein relates to a charging pad configured to thermally detect an object while a coil wirelessly transfers power to a second coil in a vehicle pad of a vehicle.

[0020] In some aspects, the technology described herein relates to a charging pad in which one or more sensors include thermocouples embedded in a printed circuit board.

[0021] In some aspects, the technology described herein relates to a charging pad, wherein the thermocouple is a T-type thermocouple.

[0022] In some aspects, the technology described herein relates to a charging pad, wherein the one or more sensors include a surface mounted thermocouple.

[0023] In some aspects, the technology described herein relates to a charging pad, wherein the one or more sensors include one hundred thermistors.

[0024] In some aspects, the technology described herein relates to a charging pad, wherein the processing circuit is configured to control operation of the charging pad based at least on the one or more sense signals by at least: determining, based on the one or more sense signals, that an object is positioned above the coil; and causing the coil to stop generating an electromagnetic field in response to determining that the object is positioned above the coil.

[0025] In some aspects, the technology described herein relates to a charging pad, wherein a maximum dimension of the object is less than 50 millimeters.

[0026] In some aspects, the technology described herein relates to a charging pad, wherein the charging pad is configured to be connected to an external power source, and the charging pad size is set to be positioned under a vehicle.

[0027] In some aspects, the technology described herein relates to a method of wireless charging with hot object detection, the method comprising: when wirelessly transferring power between a wireless charging pad and a vehicle pad of a vehicle, thermally detecting an object positioned between the wireless charging pad and the vehicle pad; and in response to the thermal detection, stopping the wirelessly transferring power.

[0028] In some aspects, the technology described herein relates to a method, wherein the object is positioned on a surface of the wireless charging pad.

[0029] In some aspects, the technology described herein relates to a method, wherein the object has a maximum dimension of 50 millimeters or less.

[0030] In some aspects, the technology described herein relates to a method, wherein the object includes metal.

[0031] In some aspects, the technology described herein relates to a method, wherein the thermal detection is performed using a thermocouple embedded in a printed circuit board. BRIEF DESCRIPTION OF DRAWINGS

[0032] Throughout the drawings, reference numbers will be reused to indicate correspondence between referenced elements. The drawings are provided to illustrate examples of the subject matter described herein and not to limit the scope of it.

[0033] Embodiments of the present disclosure are described with reference to the accompanying drawings, wherein like reference numerals refer to like elements, and wherein:

[0034] Figure 1 An example bimetallic thermocouple is illustrated.

[0035] Figure 2 An example printed circuit board (PCB) with an embedded bimetallic thermocouple is shown, according to some embodiments of the present disclosure.

[0036] Figure 3A Illustrated are example connections between bimetallic thermocouples according to embodiments of the present disclosure.

[0037] Figure 3B Example patterns of bimetallic thermocouples according to various aspects of the present disclosure are illustrated.

[0038] Figure 4A is a diagram of a wireless charging system including a wireless charger in which a temperature sensor can be deployed according to various aspects of the present disclosure.

[0039] Figure 4B An example of a wireless charger and a vehicle according to an embodiment of the present disclosure is illustrated.

[0040] Figure 4C Illustrated is a top view of an example of a wireless charger and a vehicle according to an embodiment of the present disclosure.

[0041] Figure 4D is a block diagram illustrating an example of a wireless charger and a vehicle according to an embodiment of the present disclosure.

[0042] Figure 5A is a schematic diagram illustrating an example wireless charger according to an embodiment of the present disclosure.

[0043] Figure 5B The embodiment of the present disclosure is shown in FIG. Figure 5A Example components inside a wireless charger.

[0044] Figure 5C The diagram shows an integrated Figure 5A An example temperature sensor inside a wireless charger.

[0045] Figure 5D The embodiment according to the present disclosure is shown Figure 5A Example representation of objects that can be detected above a wireless charger. DETAILED DESCRIPTION

[0046] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be implemented in a variety of different ways, for example, as defined and encompassed by the claims. In this specification, reference is made to the accompanying drawings in which the same reference numerals and / or terms can indicate identical or functionally similar elements. It should be understood that the elements illustrated in the figures are not necessarily drawn to scale. In addition, it should be understood that certain embodiments can include more elements than those illustrated in the drawings and / or a subset of the elements illustrated in the drawings. Further, some embodiments can include any suitable combination of features from two or more drawings. Titles are provided for convenience only and do not affect the scope or meaning of the claims.

[0047] In general, one or more aspects of the present disclosure relate to systems and methods for sensing temperature using one or more bimetallic thermocouples embedded in a printed circuit board (PCB). More specifically, some embodiments of the present disclosure relate to one or more bimetallic thermocouples, each of which comprises two metal traces located in one or more metal layers of the PCB. Instead of deploying one or more bimetallic thermocouples on the surface of the PCB, embedding (multiple) bimetallic thermocouples in (multiple) metal layers of the PCB can advantageously save area on the surface (e.g., top surface) of the PCB; increase the integration of the bimetallic thermocouples and associated metal traces with the PCB; reduce manufacturing costs and assembly complexity; or any suitable combination thereof.

[0048] In some embodiments, a bimetallic thermocouple embedded in a PCB (e.g., embedded in one or more metal layers of the PCB) can be made from certain combinations of metals. This can balance the temperature sensing performance of the bimetallic thermocouple with the cost of manufacturing the PCB. For example, a bimetallic thermocouple embedded in a PCB can include one metal trace made from copper and another metal trace made from constantan.

[0049] In some embodiments, multiple bimetallic thermocouples and / or other suitable thermal sensors can be used by the wireless charging mat to sense one or more temperatures associated with the wireless charging mat (e.g., the temperature at a specific location on the wireless charging mat or the average temperature over a larger or entire area of ​​the wireless charging mat). To reduce signal processing complexity and the number of temperature measurements, in some embodiments, some traces between the multiple bimetallic thermocouples can be shorted so that the average temperature associated with various locations on the PCB can be determined in a single sensed signal measurement. In some embodiments, bimetallic thermocouples (e.g., embedded in the PCB or mounted on the surface of the PCB) and / or other suitable types of thermal sensors (e.g., thermistors) can be used by the wireless charging mat to thermally detect foreign objects (e.g., metal objects) between the wireless charging mat and another wireless charging mat.

[0050] A variety of temperature sensors can be used by a device or system to detect one or more temperatures associated with the device or system. For example, bimetallic thermocouples that generate a voltage signal between the two ends of two metal traces are used to sense temperature in various devices. Typically, the metal traces of the bimetallic thermocouple are routed on or above the top of a board (e.g., a coil board, a PCB, etc.) for sensing temperature. Routing the metal traces of the bimetallic thermocouple on top of the board may take up surface area of ​​the board that could otherwise be used for other purposes (e.g., for mounting and / or connecting other circuit systems of the system). Additionally, since the top surface area of ​​a board with thermocouple traces on the PCB surface is limited, the design complexity and cost associated with manufacturing the board may increase. Therefore, it may be necessary to embed the bimetallic thermocouple into one or more layers of the board.

[0051] Embedding or integrating bimetallic thermocouples into one or more layers of a board can be challenging. For example, routing certain types of metal in layers of a PCB may not be feasible while meeting technical specifications for both the thermocouple's sensing performance and the PCB's manufacturing costs. More specifically, some thermocouple types may provide the desired temperature sensing performance (e.g., sensitivity, accuracy, etc.) but may be too expensive to embed in a metal layer of a PCB, while other thermocouple types may be more economically embedded in a metal layer of a PCB but exhibit poor temperature sensing performance.

[0052] To address at least a portion of the technical issues identified above, some aspects of the disclosed technology relate to a PCB having one or more embedded bimetallic thermocouples in one or more metal layers of the PCB for sensing a temperature associated with the PCB. To achieve accurate temperature sensing using the bimetallic thermocouples while maintaining PCB manufacturing parameters, the one or more bimetallic thermocouples may be T-type thermocouples. More specifically, the one or more bimetallic thermocouples embedded in the PCB may use copper as one metal trace and constantan as another metal trace.

[0053] In some embodiments, the PCB may include a first bimetallic thermocouple located in one or more metal layers of the PCB. The first bimetallic thermocouple may include a copper trace and a constantan trace. The first bimetallic thermocouple may be configured to sense a temperature at and / or in an area of ​​the PCB (e.g., the upper right corner). For example, an end of the copper trace of the first bimetallic thermocouple may be shorted to an end of the constantan trace of the first bimetallic thermocouple. A voltage difference between the other end of the copper trace of the first bimetallic thermocouple and the other end of the constantan trace of the first bimetallic thermocouple may be measured by processing circuitry to determine the temperature at the location of the PCB.

[0054] In some embodiments, the PCB may include a second bimetallic thermocouple located in one or more metal layers of the PCB. The second bimetallic thermocouple may include a copper trace and a constantan trace, wherein an end of the copper trace is shorted to an end of the constantan trace. The second bimetallic thermocouple may be configured to sense the temperature at another location on the PCB (e.g., the lower left corner).

[0055] In some embodiments, to reduce signal processing complexity and the number of temperature measurements, the copper trace of the first bimetallic thermocouple and the copper trace of the second bimetallic thermocouple may be shorted, and the constantan trace of the first bimetallic thermocouple and the constantan trace of the second bimetallic thermocouple may be shorted. Thus, the average temperature of the temperature sensed by the first bimetallic thermocouple and the temperature sensed by the second bimetallic thermocouple can be determined.

[0056] More specifically, the copper trace of the first bimetallic thermocouple and the copper trace of the second bimetallic thermocouple can be connected to an input terminal of the processing circuit, and the constantan trace of the first bimetallic thermocouple and the constantan trace of the second bimetallic thermocouple can be connected to another input terminal of the processing circuit. Therefore, the voltage difference measured by the processing circuit can be a weighted average of the voltage differences between the copper trace and the constantan trace of the first bimetallic thermocouple and the second bimetallic thermocouple (based on the relative resistance between the first bimetallic thermocouple and the second bimetallic thermocouple). Therefore, the processing circuit can measure the average temperature associated with the first bimetallic thermocouple and the second bimetallic thermocouple in a single electrical signal measurement.

[0057] In wireless charging applications, such as those associated with charging a vehicle's battery pack, thermal object detection is desirable. Heated objects on the surface of a wireless charging mat can be detected using thermal object detection. For example, this can detect metal objects positioned on the wireless charging mat that can become hot during wireless charging. Wireless charging can be stopped in response to the detection of a metal object. This can prevent metal objects in good contact with the surface of the wireless charging mat from catching fire during wireless charging.

[0058] In some embodiments, a bimetallic thermocouple embedded in a PCB can be used by a wireless charging pad to thermally detect foreign object(s) between the wireless charging pad and another wireless charging pad. In addition to using a bimetallic thermocouple embedded in a PCB, other types of bimetallic thermocouples (e.g., surface-mounted bimetallic thermocouples) and / or thermal sensors (e.g., thermistors) can be used by a wireless charging pad to thermally detect foreign objects.

[0059] For example, in some embodiments, a wireless charging mat may include a first coil, one or more temperature sensors (e.g., a bimetallic thermocouple embedded in a PCB, a surface-mounted bimetallic thermocouple, a thermistor), and a processing circuit or processor in communication with the one or more temperature sensors. The wireless charging mat may be configured to wirelessly transfer power between the first coil and a second coil. The first coil may be configured to generate an electromagnetic field for wireless charging. The one or more temperature sensors may be configured to generate one or more sensing signals for thermally detecting an object positioned between the first coil and the second coil. The processing circuit may be configured to control the operation of the first coil based at least on the one or more sensing signals. For example, thermal object detection may be capable of detecting a metal object. For example, upon detecting a metal object, the processing circuit may cause the wireless charging mat to stop wirelessly transferring power. This may prevent the metal object from overheating and / or catching fire.

[0060] Although aspects of the present disclosure will be described in terms of illustrative components, interactions, and routines, those skilled in the relevant art will appreciate that one or more aspects of the present disclosure can be implemented in accordance with various environments, system architectures, client computing device architectures, and the like. Similarly, references to specific devices (such as wireless charging pads) can be considered general references and are not intended to provide additional meaning or configurations for individual wireless charging pads. Further, the illustrations and exemplary configurations are not intended to be limiting and should not be interpreted as limiting the scope of the present disclosure. Additionally, these examples are intended to be illustrative in nature and should not be interpreted as limiting.

[0061] Overview of Bimetallic Thermocouples

[0062] Figure 1An example bimetallic thermocouple 100 is shown. The bimetallic thermocouple 100 includes a first metal trace 102 and a second metal trace 104. The first metal trace 102 and the second metal trace 104 are made of different types of metals and / or alloys having different Seebeck coefficients (e.g., iron, chromel, alumel, platinum, rhodium, copper, constantan, etc.). The type of metal used to make the first metal trace 102 and the second metal trace 104 can be selected based on the desired temperature sensing range (e.g., chromel and alumel can be selected to sense a temperature range between -270°C and 1370°C) and / or the application.

[0063] like Figure 1 As shown, the ends of first metal trace 102 and second metal trace 104 are shorted together to form junction 106 (e.g., the "hot" junction). The other end 108 of first metal trace 102 and the other end 110 of second metal trace 104 are not electrically connected and can be maintained at approximately the same temperature, and can be considered the "cold" junction. Due to different temperature sensing characteristics, when a temperature difference occurs between the "hot" junction and the "cold" junction, a voltage difference can be measured at the "cold" junction (e.g., between the other end 108 of first metal trace 102 and the other end 110 of second metal trace 104). By measuring and processing the voltage difference, the temperature associated with bimetallic thermocouple 100 (e.g., the temperature at junction 106) can be determined. The thermocouple output voltage across metal trace ends 108 and 110 can be used as a function of the hot junction temperature. Based on an equation relating the hot junction temperature to the thermocouple output voltage for the specific material of the thermocouple's metal traces, the hot junction temperature can be determined from the measured thermocouple output voltage.

[0064] PCB embedded bimetallic thermocouple

[0065] Figure 2 An example PCB 200 with embedded bimetallic thermocouples according to some embodiments of the present disclosure is shown. PCB 200 includes bimetallic thermocouple 202, bimetallic thermocouple 204, bimetallic thermocouple 206, bimetallic thermocouple 208, bimetallic thermocouple 212, bimetallic thermocouple 214, bimetallic thermocouple 216, and bimetallic thermocouple 218. Figure 2 As illustrated, bimetallic thermocouples 202 , 204 , 206 , and 208 are located in the flexible section of PCB 200 , and bimetallic thermocouples 212 , 214 , 216 , and 218 are located in the rigid section of PCB 200 (made of a material that is either more rigid or less flexible than the flexible section).

[0066] In some embodiments, each of bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 can be a T-type (e.g., including copper traces and constantan traces) thermocouple. Advantageously, T-type thermocouples can be easier to print during PCB manufacturing processes compared to other types of thermocouples. Therefore, using T-type thermocouples can reduce the cost and / or complexity of embedding thermocouples into PCBs.

[0067] The bimetallic thermocouple 202 may include copper traces and constantan traces. Constantan is a copper-nickel alloy that can be 55% copper and 45% nickel. A thermocouple having copper traces and constantan traces can be used to detect temperatures in the range of -200°C to 400°C. Such a thermocouple can have an electromotive force in the temperature range of -6.258 millivolts (mV) to 20.872 mV. In addition, such a thermocouple can have a Seebeck coefficient of 38.75 μV / °C at 0°C. Although Figure 2 It can be described with reference to a T-type thermocouple, but Figure 2 Any suitable principles and advantages discussed with respect to the present invention and / or any other embodiment can be applied to any suitable type of thermocouple.

[0068] like Figure 2 As shown, the copper and constantan traces at the ends of bimetallic thermocouple 202 are shorted together to form junction 202-1 (e.g., the "hot" junction). By measuring and processing the voltage difference between the other ends of bimetallic thermocouple 202, processing circuit 260 is able to determine the temperature at junction 202-1. The copper and constantan traces at the ends of bimetallic thermocouples 204, 206, and 208 can also be shorted together to form junctions 204-1, 206-1, and 208-1 (e.g., the "hot" junctions), respectively.

[0069] In some embodiments, the processing circuit 260 may include a reference resistive thermal device (RTD) 262, an amplifier and filter module 264, and a power supply circuit 266. The reference RTD 262 may change its resistance depending on temperature, thereby providing a reference voltage for the processing circuit 260. The amplifier and filter module 264 may amplify the voltage signal received from each of the bimetallic thermocouples embedded in the PCB 200. The power supply circuit 266 may generate a supply voltage for the processing circuit 260. For example, the power supply circuit 266 may generate a 3V rail for the processing circuit 260. The processing circuit 260 may include any suitable circuitry to process the output signal(s) from the thermocouple(s) and / or control the operation of the wireless charging (e.g., stop wireless charging) in response to detecting an object.

[0070] like Figure 2As shown, PCB 200 has layer 232 (e.g., a top layer), layer 234 (e.g., a dielectric layer), layer 236 (e.g., a copper layer), layer 238 (e.g., a dielectric layer), layer 240 (e.g., a constantan layer), layer 242 (e.g., a dielectric layer), and layer 244 (e.g., a bottom layer). Copper traces of bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 may be located in layer 236, and constantan traces of bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 may be located in layer 240. The traces of the bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 may be routed in any other suitable layered configuration associated with the PCB 200 and / or other suitable PCB (e.g., copper traces routed in layer 244 and constantan traces routed in layer 240; copper traces routed in layer 232 and constantan traces routed in layer 236). Although Figure 2 Bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 are shown as being connected substantially in parallel, but it should be noted that the bimetallic thermocouples embedded in PCB 200 may correspond to any other suitable pattern, including various geometric patterns (e.g., a radial pattern or any other regular or irregular pattern).

[0071] In some embodiments, for each of bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218, processing circuit 260 may measure the voltage and determine the temperature. Thus, processing circuit 260 may make eight voltage measurements to determine eight temperature values. In some other embodiments (e.g., Figure 3A As shown, the copper traces of some of the bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 may be shorted, and the constantan traces of some of the bimetallic thermocouples 202, 204, 206, 208, 212, 214, 216, and 218 may be shorted to measure the average temperature using fewer measurements, more details of which will be referenced below. Figure 3A to describe.

[0072] Figure 3AThe diagram illustrates example connections between bimetallic thermocouples 202, 204, 206, and 208 embedded in PCB 200. As mentioned above, the copper and constantan traces of bimetallic thermocouple 202 can be shorted to form junction 202-1; the copper and constantan traces of bimetallic thermocouple 204 can be shorted to form junction 204-1; the copper and constantan traces of bimetallic thermocouple 206 can be shorted to form junction 206-1; and the copper and constantan traces of bimetallic thermocouple 208 can be shorted to form junction 208-1. Although bimetallic thermocouples 202, 204, 206, and 208 are shown as being substantially connected in parallel, other geometric arrangements or patterns (e.g., radial patterns, tree patterns, etc.) can also be utilized.

[0073] like Figure 3A As shown, the copper traces of the bimetallic thermocouples 202, 204, 206, and 208 are shorted, and the constantan traces of the bimetallic thermocouples 202, 204, 206, and 208 are shorted. The copper traces of the bimetallic thermocouples 202, 204, 206, and 208 may be connected to input terminals 364 of the processing circuit 260, and the constantan traces of the bimetallic thermocouples 202, 204, 206, and 208 may be connected to input terminals 362 of the processing circuit 260. Since the copper traces and the constantan traces are shorted, respectively, the voltage difference between the input terminals 362 and the input terminals 364 may be a weighted average of the voltage differences between the copper traces and the constantan traces of the bimetallic thermocouples 202, 204, 206, and 208. The weighted average can be based on the relative resistance between the bimetallic thermocouples 202, 204, 206, and 208, which can be related to the length and / or thickness of the traces of the bimetallic thermocouples 202, 204, 206, and 208. Thus, the processing circuit 260 can measure the average temperature associated with the bimetallic thermocouples 202, 204, 206, and 208 in one measurement.

[0074] For example, without shorting any copper traces (or constantan traces) to each other, assuming that the voltage difference between the copper trace and the constantan trace of bimetallic thermocouple 202 is V1, the voltage difference between the copper trace and the constantan trace of bimetallic thermocouple 204 is V2, the voltage difference between the copper trace and the constantan trace of bimetallic thermocouple 206 is V3, and the voltage difference between the copper trace and the constantan trace of bimetallic thermocouple 208 is V4. By shorting the copper traces of bimetallic thermocouples 202, 204, 206, and 208 and the constantan traces of bimetallic thermocouples 202, 204, 206, and 208, the voltage difference between input terminal 362 and input terminal 364 can be the average value of V1, V2, V3, and V4, which are assumed to be equally weighted when averaged. Thus, rather than measuring four voltage differences and processing them individually to determine four temperatures, processing circuitry 260 can make one measurement and process the average voltage difference to determine an average temperature. Advantageously, by shorting the first and second metal traces of the thermocouple, processing circuitry 260 can determine an average temperature over a large area associated with PCB 200 with reduced signal processing complexity and a reduced number of voltage measurements.

[0075] Figure 3B An example wiring pattern 350 of a bimetallic thermocouple embedded in a PCB according to some embodiments of the present disclosure is illustrated. Figure 3B As shown, the wiring pattern 350 includes bimetallic thermocouples 320-1, 320-2, 320-3, and 320-4. The bimetallic thermocouple 320 includes a radial pattern in which each of the bimetallic thermocouples 320-1, 320-2, 320-3, 320-4, etc. is wired to radiate outward from a central region. The object 330 generating heat can be Figure 3B 3 is detected above the wiring pattern 350 in the PCB. In some embodiments, some of the bimetallic thermocouples 320-1, 320-2, 320-3, 320-4, etc. can share one or more "hot" wires. For example, bimetallic thermocouples 320-4 and 320-3 share "hot" wire 340. It should be noted that according to other embodiments of the present disclosure, other types of connections between bimetallic thermocouples (e.g., tree-like connections) can also be used to embed the bimetallic thermocouples into the PCB.

[0076] Thermocouples embedded in PCBs can be used in a variety of applications. Example applications of thermocouples embedded in PCBs include, but are not limited to, integrated magnetic devices, low power field effect transistors, and / or other integrated circuits, temperature sensing associated with wireless charging (e.g., embedded in a PCB on which a coil for wireless charging is positioned), or for battery temperature measurement. In battery temperature measurement, embedded thermocouples can be implemented at a flexible PCB for fast and accurate temperature measurement. Embedded thermocouple plates can include more measurement points, relatively low cost, and relatively low design effort. Parallel thermocouples in accordance with any suitable principles and advantages disclosed herein can be implemented in applications in which an average measurement is desired rather than an individual measurement and / or collective measurement of a larger area.

[0077] Thermal sensing for wireless charging

[0078] In accordance with one or more aspects of the disclosure, a temperature sensor such as a bimetallic thermocouple embedded in the PCB 200 illustrated above, one or more other types of bimetallic thermocouples (e.g., surface mount bimetallic thermocouples), and / or one or more other suitable thermal sensors (e.g., thermistors) can be integrated into a wireless charging pad (e.g., a ground pad) of a wireless charging system for sensing temperature, which can be useful for various applications. With the temperature sensor, one or more objects positioned between coils of the wireless charging pad can be detected. In some embodiments, the temperature sensor is configured to monitor a surface temperature of the wireless charging pad. For example, a PCB embedded with a bimetallic thermocouple can be deployed inside the wireless charging pad to determine a surface temperature of the wireless charging pad. As mentioned above, a bimetallic thermocouple includes two metal strips or traces that are associated with different Seebeck coefficients. When the bimetallic thermocouple is exposed to different environmental inputs (e.g., temperature changes), electrons can diffuse along the wires to create a voltage difference at the end of the metal traces at the cold wire for indicating a sensed temperature.

[0079] In some embodiments, a wireless charging pad can include a PCB printed with a plurality of bimetallic thermocouples to enable temperature monitoring of a determined and / or defined surface area of the wireless charging pad. In some embodiments, a plurality of bimetallic thermocouples with wire nodes can be deployed (e.g., under a surface of the wireless charging pad) to sense a temperature over an entire surface area or a particular portion of the surface area of the wireless charging pad.

[0080] In some embodiments, bimetallic thermocouples can be included in the wireless charging mat for thermal detection of one or more objects on or near the surface of the wireless charging mat, thereby mitigating unwanted heat generation that could lead to fire. Alternatively or additionally, one or more other types of sensors (e.g., magnetic field sensing, inductance change sensing, etc.) can be included in the wireless charging mat for detecting object(s) positioned between the coils during wireless charging. For example, a matrix of passive sensing mini-coils on top of a wireless charging mat (e.g., a grounded mat) can be used to detect objects (e.g., metal objects) by monitoring magnetic field disturbances caused by these objects during inductive charging. As another example, a collection of active drive coils on top of a grounded mat can be used to detect objects by monitoring changes in coil characteristics (e.g., inductance changes) caused by these objects during inductive charging. In another example related to hot object detection, a wireless charging mat can utilize a thermal camera (e.g., integrated as part of the wireless charging mat or external to the wireless charging mat) to monitor areas of the wireless charging mat for changes in temperature or a threshold temperature for object detection and / or operational safety.

[0081] In some embodiments, a sensed signal generated by a temperature sensor integrated with a wireless charging mat of a wireless charging system can be provided as temperature input data to a control circuit system (e.g., a processor or any other suitable circuit system) associated with the wireless charging system. The temperature input data can be monitored to detect whether the wireless charging mat may be experiencing a thermal issue. For example, the input can be processed by comparing a temperature threshold, a temperature change threshold, and / or other processing rules. Based on the processed temperature input (and in some cases one or more other inputs), the control circuit system can mitigate and / or determine the characterized thermal issue. Thermal issue mitigation techniques can include, but are not limited to, termination of a wireless charging process, modification of one or more operating parameters, initiation of a self-test process, initiation of a thermal management process (e.g., a fire extinguishing process, a ventilation process), an alarm and / or warning process, a notification process, the like, or any suitable combination thereof.

[0082] Overview of Wireless Charging

[0083] Figures 4A to 4C 4 is a diagram of an example of a wireless charging system 400 in which a temperature sensor disclosed herein (e.g., a bimetallic thermocouple embedded in a PCB, a surface-mounted bimetallic thermocouple, a thermistor, etc.) can be integrated for thermal detection of an object. More specifically, according to some embodiments, a wireless charger 410 (also referred to as a "wireless charging pad" or "grounding pad") can be configured to charge a battery pack included in a vehicle. For illustrative purposes, an electric vehicle 412 ( Figure 4B andFigure 4C ). However, only an electric vehicle 412 is illustrated, and the wireless charger 410 can be configured to charge any battery-powered device, equipment, or platform capable of receiving wireless energy from the wireless charger. For example, according to the embodiments disclosed herein, any battery-powered electronic device, robot, watercraft, unmanned aerial vehicle, etc. having a component for receiving energy generated from a wireless charger (e.g., a receiver coil connected to a battery pack for charging the battery pack) can be coupled to a wireless charger for charging the battery pack. The wireless charging disclosed herein can be applied to any suitable vehicle, including electric vehicles with battery packs and hybrid vehicles including an internal combustion engine and a battery pack.

[0084] Figure 4A is a diagram of a wireless charging system 400 including a wireless charger 410 (such as an induction-based wireless charger) in accordance with various aspects of the present disclosure. Wireless charging system 400 illustratively can correspond to commercial implementations such as parking lots, parking spaces, charging kiosks, and the like. Wireless charging system 400 can also correspond to private or other non-commercial implementations such as private homes, garages, and the like. By way of illustrative example, in accordance with some embodiments, wireless charger 410 can be configured to generate a variable electromagnetic field.

[0085] Likewise Figure 4A As shown, wireless charger 410 (which can also be referred to as a transmission component) can correspond to an independent component that can be operated to be installed or placed on a floor or other flat surface. In other embodiments, wireless charger 410 can be integrated or combined with one or more other devices or components.

[0086] The wireless charger 410 can be connected to one or more energy sources (e.g., a power source), such as input from a utility company, a real-time power source (e.g., solar cells or wind power), a storage battery, or any suitable combination thereof. The energy source can be configured to provide input AC power as described herein. In some examples, the wireless charger 410 can be connected to the power source via a direct electrical connection 420, such as via an energy source 430 located on a wall surface (e.g., a junction box).

[0087] like Figure 4A As further depicted in FIG, the wireless charger 410 can be designed to have a form factor that is allowed within a specified area, which is determined by the form factor of the device intended to receive power from the wireless charger 410. For example, if the wireless charger 410 is intended to power a vehicle 412 ( Figure 4BIf a battery pack (shown in FIG. 4 ) is to be charged by wireless charger 410, the form factor of wireless charger 410 will allow vehicle 412 to be positioned directly above the top surface of wireless charger 410. The dimensions of wireless charger 410 (such as its height and / or width) can be determined to ensure that the gap between the top surface of wireless charger 410 and the bottom surface of the receiver device falls within a specific range. This range can be a factor used to enhance and / or optimize energy transfer between wireless charger 410 and the receiver device and can be defined by a minimum distance and a maximum distance that promote efficient energy transfer. The appropriate distance can vary depending on the specific application. In some embodiments, wireless charger 410 can include one or additional mechanisms for adjusting (e.g., statically and / or dynamically adjusting) this distance or changing the relative positioning between wireless charger 410 and the receiver device to enhance and / or optimize charging efficiency.

[0088] The wireless charger 410 can provide sufficient power to charge the battery pack of the electric vehicle and can also perform thermal detection on (multiple) objects. In some embodiments, the wireless charger 410 can be configured to charge the battery pack of the vehicle, wherein the battery pack can have a nominal voltage exceeding 200 volts (e.g., a nominal voltage of approximately 350 volts or 355 volts) and a maximum voltage of 400 volts. In some embodiments, the wireless charger 410 can be configured to supply 800 volts of DC power. In some embodiments, the wireless charger 410 can supply a voltage in the range of approximately 200 volts to 800 volts.

[0089] Figure 4B and Figure 4C An example of a wireless charger 410 and a vehicle 412 (eg, an electric vehicle) is illustrated. Figure 4C Pictured Figure 4B A top view of an example of a wireless charger 410 and a vehicle 412 is shown. Figure 4B and Figure 4C As shown, the wireless charger 410 and the vehicle 412 can be coupled to charge the battery pack ( Figure 4B and Figure 4C For example, wireless charger 410 and receiver coil 404 of vehicle 412 can be coupled at a threshold distance. The threshold distance can be defined as a distance range that provides efficient energy transfer between wireless charger 410 and receiver coil 404. For example, if efficient energy transfer is defined as 85% of the energy generated by wireless charger 410, then the threshold distance can correspond to a distance that provides at least 85% of the energy transfer between wireless charger 410 and receiver coil 404 of vehicle 412.

[0090] According to aspects of the present disclosure, the wireless charger 410 can be configured to transfer energy via inductive coupling with the receiver coil 404, such that the receiver coil 404 can be configured to receive energy from the wireless charger 410 via inductive coupling with the wireless charger 410. Illustratively, the wireless charger 410 can include an energy transfer component, such as a transmitter coil. This transmitter coil can be an inductive coil. The wireless charger 410 can be generally referred to as a charging station, charging pad, or grounding pad. This transmitter coil can be configured to induce an electromagnetic field from power received from an energy source. The power can be provided as alternating current (AC) from a power source (such as a wall outlet, an external battery, etc.). This alternating current (AC) can pass through the transmitter coil. For example, this AC current can flow into the transmitter coil, causing charge to move through the transmitter coil. This movement in the transmitter coil can induce (or induce) an electromagnetic field. Illustratively, receiver coil 404 included in vehicle 412 can receive an electromagnetic field by being positioned within a specific distance from wireless charger 410 (e.g., receiver coil 404 is positioned above wireless charger 410 within a threshold distance). The threshold distance can be determined based on the strength of the generated electromagnetic field and criteria defining the ratio of transferred energy between wireless charger 410 and receiver coil 404. When receiver coil 404 receives the electromagnetic field generated by the transmitter coil of wireless charger 410, the strength of the electromagnetic field can fluctuate based, at least in part, on variations or fluctuations in the AC amplitude. This variation in the electromagnetic field can generate an alternating current in the receiver coil on vehicle 412. The AC current induced in receiver coil 404 can then be converted to DC current to charge the battery of vehicle 412. For example, the induced AC current can be transmitted through a rectifier, which can convert the induced AC current into DC current. Vehicle 412 can then be configured to use the DC current to charge its battery, provide operating power, or a combination thereof.

[0091] Figure 4D The figure shows a general block diagram of a wireless charging system including a wireless charger 410 wirelessly coupled to a vehicle 412. The wireless coupling can be via an induction-based electromagnetic field induced by a transmitter coil of the wireless charger 410. The wireless charger 410 is also connected to one or more energy sources 430, such as a power wall, an external battery, an external generator (e.g., solar power), etc. Although the wireless charger 410 is shown as being directly connected to the energy source 430, at least some portion of the input AC power can also be provided via wireless transmission methods. Additionally, in embodiments with multiple power sources, the environment can also include various switching components to enable selection of energy from the energy source 430 or a combination of energy sources 430.

[0092] In some embodiments, as Figure 4DAs shown, wireless charger 410 and vehicle 412 are coupled via an electromagnetic field generated by a transmitter coil of wireless charger 410. According to aspects of the present disclosure, wireless charger 410 can be configured to transfer energy via inductive coupling with a receiver coil 404 of vehicle 412, such that receiver coil 404 is configured to receive energy from wireless charger 410 via inductive coupling with wireless charger 410. In some embodiments, energy source(s) 430 can provide input AC power to wireless charger 410. This AC power comprises an AC current and passes through the transmitter coil. Electromagnetic fields can be induced by the transmitter coil due to the AC current. The induced electromagnetic fields can radiate outward (e.g., from wireless charger 410) in a certain direction, such as a vertical direction on the wireless charger (e.g., if the transmitter coil is implemented in the wireless charger so that it faces vertically upward from wireless charger 410). In some cases, the strength of these vertically propagating electromagnetic fields can decrease in proportion to the distance from the top surface of wireless charger 410. Thus, the vehicle 412 (eg, the receiver coil 404 ) can be positioned above the wireless charger 410 within a threshold distance that can provide a desired strength of the electromagnetic field.

[0093] Example Applications in Wireless Charging

[0094] Figure 5A FIG. 4 illustrates a block diagram of a wireless charger 410 in which embodiments of the present disclosure can be implemented. The wireless charger 410 can include at least one coil ( Figures 5B to 5C ) for generating a magnetic field from an input current provided by a self-energy source 430. Figure 5A As illustrated, the input current can be provided by a direct electrical connection 420 .

[0095] In some embodiments, the core portion 502 of the wireless charger 410 can include a temperature sensor, such as bimetallic thermocouple(s) embedded in a PCB, a surface-mounted bimetallic thermocouple, a thermistor, or any suitable combination thereof. More specifically, a plurality of bimetallic thermocouples and / or thermistors can be disposed below the surface of the core portion 502 for sensing temperature(s) associated with various locations of the core portion 502 of the wireless charger 410. For example, the plurality of bimetallic thermocouples and / or thermistors can sense temperature to enable the wireless charger 410 to perform thermal detection of heated objects above the core portion 502.

[0096] In some embodiments, the wireless charger 410 can also include various sensor components 504 (e.g., radar sensors) for various applications. By way of illustration, the sensor components 504A, 504B, 504C, and 504D can be configured for various functions, such as object detection, vehicle 412 detection, distance measurement to vehicle 412, environmental sensing (e.g., using a temperature sensor, humidity sensor, etc.), pressure sensing, and the like. In some embodiments, the sensor component 504 can include a radar sensor. The sensor component 504 can include logic and processing components related to the charging process, including object detection, temperature measurement, operational measurement, operational control, safety measurement, communication components, and the like, or any suitable combination thereof.

[0097] Figure 5B 4 shows example layers of components within the wireless charger 410 according to some embodiments of the present disclosure. In some embodiments, the transmitter coil 510 can be located above or below the center portion 502 of the wireless charger 410. Additionally, various sensor components 504 can be disposed around the transmitter coil 510 of the wireless charger 410.

[0098] like Figure 5B As shown, the transmitter coil 510 can be configured to induce an electromagnetic field by receiving AC from the energy source(s) 430. The transmitter coil 510 may be capable of operating within various power ranges, such as up to approximately 500 kilowatts (kW). In some embodiments, the transmitter coil 510 can include a circular shape, and in some other embodiments, various shapes, such as a rectangular shape, can be used.

[0099] In some embodiments, the wireless charger 410 can further include a PCB 520 (e.g., a control board for controlling the operation of the wireless charger 410). The PCB 520 can be or include one or more PCBs, such as the PCB 200 that includes embedded bimetallic thermocouple(s) for sensing the temperature associated with the wireless charger 410. Other temperature sensors (e.g., thermistors) can alternatively or additionally be disposed in and / or on the PCB 520. Thus, the PCB 520 can utilize bimetallic thermocouples or other temperature sensors to measure the temperature associated with the wireless charger 410 for various purposes, such as detecting heated objects on the wireless charger 410.

[0100] In some embodiments, PCB 520 can be positioned in a layer below transmitter coil 510. In addition to one or more bimetallic thermocouples, PCB 520 can also include at least one or more processors and a power supply module thereon. For example, various electronic components (such as memory, communication modules, etc.) can be implemented in PCB 520. These electronic components are provided as examples only, and PCB 520 can include more or fewer components thereon based on the specific application.

[0101] Figure 5C An example temperature sensor is shown integrated into a wireless charger 410 including a transmitter coil 510 according to some embodiments of the present disclosure. Figure 5C As shown, multiple temperature sensors 506 and 508 may be disposed on or below the central portion 502 of the wireless charger 410. The multiple temperature sensors 506 and 508 can include any suitable combination of bimetallic thermocouples, thermistors, or other types of temperature sensors. In some embodiments, the number of temperature sensors 506 and / or 508 may be determined based on the area of ​​the wireless charger 410, the type of temperature sensor utilized, and the desired application. The minimum size of the object to be thermally detected may influence the number of temperature sensors included in the wireless charger 410. In some embodiments, to detect heated object(s) having a maximum size of approximately 50 millimeters (mm), more than 500 temperature sensors 506 and / or 508 may be integrated into the wireless charger 410. For example, there may be more than 500 bimetallic thermocouples embedded in one or more metal layers of the PCB 520, or there may be more than 500 surface-mounted thermocouples. To detect smaller objects, more temperature sensors may be included in the wireless charger 410. On the other hand, to detect larger objects, fewer temperature sensors may be included. In some other embodiments, there may be more than one hundred temperature sensors (such as thermistors) in and / or on PCB 520 for detecting heated object(s) having a length of approximately 50 mm.

[0102] Figure 5D An example representation of an object 550 positioned above wireless charger 410 according to an embodiment of the present disclosure is shown. Object 550 may be a metal object positioned above wireless charger 410 during a wireless charging process. As a result, object 550 may be heated. Temperature sensors 506 and / or 508 (e.g., bimetallic thermocouples and / or other types of temperature sensors) may be used to detect object 550.

[0103] In some embodiments, the number of temperature sensors 506 and / or 508 may be determined based on the size of object 550. More specifically, the surface of wireless charger 410 may not spread or conduct heat well due to its low thermal conductivity. Consequently, most of the heat generated during wireless charging may accumulate within object 550. Therefore, the density of temperature sensors 506 and / or 508 may be related to the size of object 550. For example, if object 550 is a coin with a diameter of 50 mm, the number of temperature sensors 506 and / or 508 may need to be a value (e.g., 100, 200, 300, 400, 500, etc., depending on the surface area of ​​wireless charger 410) such that every 50 mm of wireless charger 410 is covered by the temperature sensing capability of a temperature sensor.

[0104] in conclusion

[0105] The foregoing disclosure is not intended to limit the present disclosure to the precise form disclosed or to the specific field of use. Therefore, it is contemplated that various alternate embodiments of the present disclosure and / or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the present disclosure. Having thus described the embodiments of the present disclosure, one of ordinary skill in the art will recognize that changes in form and detail may be made without departing from the scope of the present disclosure. Therefore, the present disclosure is limited only by the claims.

[0106] It should be understood that not all objectives or advantages may be achieved according to any particular example described herein. Thus, for example, one skilled in the art will recognize that some examples may operate in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as may be taught or suggested herein.

[0107] All processes described herein can be implemented in software code modules and fully automated via the software code modules, which are executed by a computing system including a computer or processor. The code modules can be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all of the methods can be implemented in dedicated computer hardware.

[0108] Many other variations other than those described herein will be apparent from this disclosure. For example, depending on the example, some actions, events, or functions of any algorithm described herein can be performed in a different order, can be added, merged, or omitted entirely (e.g., not all described actions or events are necessary for the practice of the algorithm). Additionally, in some examples, actions or events can be performed simultaneously, for example, by multithreading, interrupt handling, or multiple processors or processor cores, or on other parallel architectures, rather than sequentially. Additionally, different tasks or processes can be performed by different machines and / or computing systems that can work together.

[0109] The various illustrative logic blocks and modules described in conjunction with the examples disclosed herein can be implemented or performed by a machine designed to perform the functions described herein, such as a processing unit or processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The processor can be a microprocessor, but in alternative embodiments, the processor can be a controller, a microcontroller, or a state machine, a combination thereof, or the like. The processor can include circuitry for processing computer-executable instructions. In some examples, the processor includes an FPGA or other programmable device that performs logic operations without processing computer-executable instructions. The processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, a microprocessor together with a DSP core, or any other such configuration. Although primarily described herein with respect to digital technology, the processor can also include primarily analog components. The computing environment can include any type of computer system, including but not limited to a microprocessor-based computer system, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computing engine within an appliance, to name a few.

[0110] The elements of the methods, processes, routines, or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly in hardware, in software modules executed by a processor device, or in a combination of the two. The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of non-transitory computer-readable storage medium. An exemplary storage medium can be coupled to the processor device so that the processor device can read information from the storage medium and write information to the storage medium. In an alternative embodiment, the storage medium can be an integral part of the processor device. The processor device and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In an alternative embodiment, the processor device and the storage medium can reside in a user terminal as discrete components.

[0111] The processes described herein or illustrated in the drawings of the present disclosure can be started in response to an event, such as starting according to a predetermined or dynamically determined schedule, starting on demand when initiated by a user or system administrator, or starting in response to some other event. When such a process is initiated, an executable program instruction set stored on one or more non-transitory computer-readable media (e.g., a hard drive, flash memory, removable media, etc.) can be loaded into the memory (e.g., RAM) of a server or other computing device. The executable instructions can then be executed by a hardware-based computer processor of the computing device. In some embodiments, such a process or portions thereof can be implemented serially or in parallel on multiple computing devices and / or multiple processors.

[0112] Unless otherwise specifically noted, conditional language (such as "can," "could," "might," or "may," etc.) is understood within the context as generally used to convey that some examples include certain features, elements, and / or steps, while other examples do not. Thus, such conditional language is generally not intended to imply that features, elements, and / or steps are in any way examples, or that examples necessarily include logic for deciding, with or without user input or prompting, whether such features, elements, and / or steps are included in any particular example or will be performed in any particular example.

[0113] Unless specifically noted otherwise, disjunctive language (such as the phrase "at least one of X, Y, or Z") should be understood in context as generally used to indicate that an item, term, etc. can be X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctive language is generally not intended to, and should not, imply that some examples require the presence of at least one X, at least one Y, or at least one Z, respectively.

[0114] Any process description, element, or block in the flowcharts described herein and / or depicted in the accompanying drawings should be understood to potentially represent a module, segment, or portion of code that includes executable instructions for implementing the specific logical functions or elements in the process. Alternative examples are included within the scope of the examples described herein, in which elements or functions may be deleted, executed out of the order shown or discussed, including substantially simultaneously, or executed in reverse order, depending on the functionality involved, as will be understood by those skilled in the art.

[0115] It should be emphasized that many variations and modifications may be made to the above examples, and that the elements of these examples should be understood as being within other acceptable examples. All such modifications and variations are intended to be included within the scope of the present disclosure.

[0116] Any process description, element or block in the flowcharts described herein and / or depicted in the accompanying drawings should be understood to potentially represent a module, segment or portion of code that includes executable instructions for implementing the specific logical functions or elements in the process. Alternate implementations are included within the scope of the examples described herein, in which elements or functions may be deleted, executed out of the order shown or discussed, including substantially simultaneously or in reverse order, depending on the functionality involved, as will be understood by those skilled in the art.

[0117] Unless expressly stated otherwise, articles such as "a" or "an" should generally be construed to include one or more of the described items. Thus, a phrase such as "a device configured to perform XXX" is intended to include one or more of the recited devices. Such one or more recited devices can also be collectively configured to perform the recited statements. For example, "a processor configured to perform statements A, B, and C" can include a first processor configured to perform statement A working together with a second processor configured to perform statements B and C.

Claims

1. A printed circuit board (PCB), comprising: a thermocouple embedded in the PCB, the thermocouple comprising a first metal trace and a second metal trace, The thermocouple is configured to generate a voltage indicative of temperature. 2 . The PCB of claim 1 , wherein the first metal trace comprises copper, and wherein the second metal trace comprises constantan. 3 . The PCB of claim 1 , further comprising a dielectric layer positioned between the first metal trace and the second metal trace. 4 . The PCB of claim 3 , further comprising a second dielectric layer and a third dielectric layer, wherein the first metal trace and the second metal trace are positioned between the second dielectric layer and the third dielectric layer. 5 . The PCB of claim 1 , further comprising a second thermocouple embedded in the PCB, the second thermocouple configured to generate a second voltage indicative of a second temperature, wherein the temperature and the second temperature are associated with different locations.

6. The PCB of claim 5, wherein the first metal trace of the second thermocouple has an end shorted to the first metal trace of the thermocouple, and wherein the second metal trace of the second thermocouple has an end shorted to the second metal trace of the thermocouple. The PCB according to claim 5 , wherein the thermocouple and the second thermocouple are arranged in parallel. The PCB of claim 5 , wherein the thermocouple and the second thermocouple are connected to the same thermal wire.

9. The PCB according to claim 1, further comprising: The surface layer, positioned above the thermocouple, The surface layer includes a coil configured to generate an electromagnetic field for wireless charging.

10. The PCB of claim 1, further comprising 100 additional embedded thermocouples.

11. A wireless charging pad comprising the PCB according to claim 1.

12. A PCB assembly comprising the PCB of claim 1 and a processing circuit configured to determine the temperature based on the voltage.

13. A charging pad comprising: a coil configured to generate an electromagnetic field for wireless charging; one or more sensors configured to generate one or more sensing signals for thermally detecting an object positioned above the coil; as well as Processing circuitry is in communication with the one or more sensors, the processing circuitry being configured to control operation of the charging pad based at least on the one or more sensed signals.

14. The charging pad of claim 13, wherein the charging pad is configured to thermally detect the object while the coil is wirelessly transferring power to a second coil in a vehicle pad of a vehicle.

15. The charging pad of claim 13, wherein the one or more sensors comprise thermocouples embedded in a printed circuit board. The charging pad of claim 15 , wherein the thermocouple is a T-type thermocouple.

17. The charging pad of claim 13, wherein the one or more sensors comprise surface mounted thermocouples.

18. The charging pad of claim 13, wherein the one or more sensors include one hundred thermistors.

19. The charging pad of claim 13, wherein the processing circuit is configured to control the operation of the charging pad based at least on the one or more sensing signals by at least the following steps: determining that the object is positioned above the coil based on the one or more sensing signals; and In response to determining that the object is positioned above the coil, the coil is caused to cease generating the electromagnetic field.

20. The charging pad of claim 13, wherein the largest dimension of the object is less than 50 mm.

21. The charging pad of claim 13, wherein the charging pad is configured to be connected to an external power source and is sized to be positioned under a vehicle.

22. A wireless charging method with hot object detection, the method comprising: thermally detecting an object positioned between the wireless charging pad and the vehicle pad of the vehicle while wirelessly transferring power between the wireless charging pad and the vehicle pad; as well as In response to the heat detection, the wireless transfer of power is stopped.

23. The method of claim 22, wherein the object is positioned on a surface of the wireless charging pad.

24. The method of claim 22, wherein the object has a maximum dimension of 50 mm or less.

25. The method of claim 22, wherein the object comprises metal.

26. The method of claim 22, wherein the thermal detection is performed using thermocouples embedded in a printed circuit board.

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