The field relates to integrated device packages, and in particular, to integrated device packages that include a thermoelectric generator (TEG) device.
Integrated device packages can be used in a variety of larger electronic systems to provide sensors, transducers, processors, memory devices, or other types of devices for use in a variety of environments. In some environments, it may be challenging to provide electrical power and/or electrical communication between the integrated device package (or the larger electronic system) and an external device disposed in another environment or location. For example, in some systems, it may be economically or technically inefficient or physically challenging to provide electrical power or communications lines between the integrated device package and the external device. Use of a battery for powering such devices can result in critical downtime for operation of the packaged device between depletion and recharging or replacement of the battery. Accordingly, there remains a continuing need for improved integrated device packages for use in different environments.
In one embodiment, an integrated device package is disclosed. The integrated device package can include a package substrate and a thermoelectric generator (“TEG”) device electrically connected to the package substrate, the TEG device configured to convert thermal energy to electrical current. A magnet can be disposed over a front side of the TEG device, the magnet configured to connect to a heat source and to define a thermally conductive pathway between the heat source and the TEG device.
In another embodiment, integrated device package can include a package substrate comprising an aperture and a thermoelectric generator (“TEG”) device positioned in the aperture and electrically connected to the package substrate, the TEG device configured to convert thermal energy to electrical current. A thermally conductive element can be disposed over a first side of the TEG device, the thermally conductive element configured to define a thermally conductive pathway between a heat source and the TEG device.
In another embodiment, an integrated device package can include a first thermally conductive element and a second thermally conductive element. The package can include a package substrate disposed between the first and the second thermally conductive elements. A thermoelectric generator (“TEG”) device can be disposed between the first and second thermally conductive elements and electrically connected to the package substrate. The TEG device can be configured to generate electricity from thermal energy based on a temperature difference between the first and second thermally conductive elements
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. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.
Specific implementations of the invention will now be described with reference to the following drawings, which are provided by way of example, and not limitation.
Various embodiments disclosed herein relate to integrated device packages that include one or more thermoelectric generator (“TEG”) devices. A TEG device generates electrical current from thermal energy based on a temperature difference (ΔT) between a first side of the TEG device (e.g., a hot side of the TEG device) and a second side of the TEG device (e.g., a cold side of the TEG device). In various TEG devices, the greater the temperature difference ΔT, the greater amount of electrical energy the TEG may generate. The embodiments disclosed herein can utilize a TEG device in connection with a high temperature heat source such as a steam pipe, a radioactive element (such as those used in space probes), a tailpipe or engine of an automobile, etc. The embodiments disclosed herein can be configured to monitor vibration of steam pipes or boiler walls in a power plant, to monitor vibration of water pumps in a water treatment plant, and any other suitable sensing application. One challenge to manufacturing an efficient thermoelectric generator system is to provide high thermal conductivity between the first and second sides of the TEG device (e.g., between the hot and cold sides of the TEG), as well as a large ΔT throughout the operation of the system. Various embodiments disclosed herein provide an integrated device package with a TEG device that can operate at a wide range of temperature differences ΔT, and may be particularly beneficial for systems used with relatively small temperature difference between first and second sides of the TEG device. The embodiments disclosed herein can also provide a very low thermal resistance so as to reduce thermal losses in the system.
The embodiments disclosed herein may be beneficial for electronic systems having sensors that operate for a relatively long duration, and/or for multiple series of measurements without replacement. The embodiments disclosed herein may also be particularly beneficial for systems used in remote and/or inaccessible places where an electrical power source may not be easily reachable and/or where replacement of an electricity source may be difficult. The integrated device packages disclosed herein can be mechanically and thermally connected to a support structure, which can act as a first heat source for the package. For example, the support structure or heat source (such as a steam pipe) can have a relatively high temperature so as to act as a heat source for the integrated device package and TEG device. Thermal energy from the support structure or heat source can be converted to electrical current by the TEG device. The electrical current generated by the TEG device can be supplied to provide electrical power to one or more integrated device dies of the package. For example, in some embodiments, the electrical current can supply power to a sensor die, a processor die configured to process signals (e.g., signals transduced by the sensor die), a communications die (e.g., a transmitter configured to wirelessly transmit wireless signals to an external device), a memory die, and/or any other suitable type of integrated device die, either directly or indirectly through a battery that the TEG device recharges. In some embodiments, the integrated device dies can monitor the operational environment, including, e.g., the temperature, humidity, etc. of a steam pipe to which the package is attached.
Beneficially, the integrated device package can generate electrical power sufficient to power the operation of the integrated device package, without requiring connection to an external power supply. Moreover, the integrated device package can electrically communicate with an external device (such as a computing device) over a wireless network by one or more communications dies in the package, which also may be powered, directly or indirectly, by the TEG device. Thus, the embodiments disclosed herein enable sensing, processing, and/or communications capabilities in remote environments without requiring a connection to an external power source.
The substrate 14 can comprise any suitable type of package substrate. In the illustrated embodiment, the substrate 14 comprises a laminate substrate (e.g., a printed circuit board), but in other embodiments, the substrate 14 can comprise a leadframe, a molded leadframe, a ceramic substrate, a polymer substrate, etc. As shown in
In some embodiments, the second thermally conductive element 12 can comprise, or can act as, a heat sink. As shown in
As shown in
As shown in
The thermal interface element 11 may comprise a material configured to reduce or eliminate the stresses transmitted to the TEG device 16 (e.g., to the first side 31) and/or the first element 10, by providing the thermal interface element 11 as a sufficiently compliant buffer material to absorb expansion and/or contraction of the first element 10 relative to the TEG device 16, and by absorbing vibrations. In some embodiments, the thermal interface element 11 may comprise any suitable flexible or compliant material that is thermally conductive, such as an amine epoxy, amide epoxy, cycloaliphatic epoxy, amine adduct epoxy or any other suitable materials for the operational environment. In various embodiments, the thermal interface element 11 can comprise a thermal pad, a thermal grease, etc. The thermal interface element 11 can thereby enable the first thermally conductive element 10 to mechanically float over the TEG device 16 while providing a low thermal resistance pathway to the TEG device 16.
The TEG device 16 can generate electrical current based on a temperature difference ΔT between the first (e.g., bottom) side 31 of the TEG device 16 and the second (e.g., top) side 33 of the TEG device 16 opposite the first side 31. In various embodiments, the TEG device 16 can comprise a multi-layered semiconductor die that creates electrical current in the presence of a thermal gradient across the layers. In some embodiments, the TEG device 16 can comprise a microelectromechanical systems (MEMS) die, but other types of TEG devices may be used. In various embodiments, the TEG device 16 can comprise a TEG die including an integrated single chip thermoelectric energy harvester that comprises a plurality of electrically connected n-type and p-type thermoelectric element. In some embodiments, the TEG device 16 can convert thermal energy to electricity for temperature differences ΔT of at least 5° C., at least 10° C., or at least 15° C. The TEG device 16 can generate electrical current at an electrical power level that is in a range of 0.00001% to 0.1% of a thermal power level provided to the TEG device 16, or in a range of 0.0001 to 0.1% of the thermal power level. The TEG device 16 may generate 25 microwatts to 150 microwatts per 10° C. in temperature difference ΔT. For example, at a temperature difference ΔT of about 10° C., 1 W of thermal power supplied to the TEG device 16 can generate about 0.1 mW of electrical power in some arrangements. For additional examples of such a TEG, the following reference is hereby incorporated by reference herein in its entirety and for all purposes: U.S. Patent Publication No. 2014/0246066 A1, entitled “WAFER SCALE THERMOELECTRIC ENERGY HARVESTER,” published Sep. 4, 2014. As shown in
The first thermally conductive element 10 can contact the heat source 22 (which may be outside the package or electronic device, such as a pipe carrying hot fluid) along a first thermal interface surface 24 to transfer first thermal energy between the heat source 22 and the first side 31 of the TEG device 16, such that the first element 10 defines a thermally conductive pathway between the first heat source 22 and the first side 31 of the TEG device 16. The first element 10 may comprise any thermally conductive material that efficiently conducts heat, such as iron, copper, tungsten, etc. In some embodiments, e.g., if a delay in heat transfer is desired, lower thermally conductive materials may be used. In other arrangements, the package can comprise one or more energy storage devices (such as a battery) to store electrical energy generated by the TEG device. In the illustrated embodiment, the first thermally conductive element 10 comprises a magnetic material, or magnet, such that the thermally conductive element 10 can be directly mechanically and thermally connected to the heat source 22. Advantageously, using a magnetic, thermally conductive material for the first element 10 can enable the first element 10 to act as both a thermally conductive pathway and a mechanical connector for attaching the package 1 to the external heat source 22. Such an arrangement can simplify the design of the package 1, reduce the overall size of the package 1, and/or increase the efficiency of heat conductivity between the first thermal interface surface 24 and the first side 31 of the TEG device 16.
As explained above, the second thermally conductive element 12 can connect to the second side 33 of the TEG device 16. The second side 33 of the TEG device 16 and the second thermally conductive element 12 can define a second thermal pathway between the TEG device 16 and the outside environs (e.g., by way of the fins 12b and corresponding air gaps therebetween). The resulting temperature difference ΔT between the first and second thermally conductive elements 10, 12 can create a thermal gradient across the TEG device 16 sufficient to generate electrical current.
The plurality of electrical components 18 can include one or more of a sensor die, a wireless communications die (e.g., a wireless transmitter die and/or receiver die), a processor die or microcontroller, a memory die, and other components suitable for the purpose of operating the package 1. The electrical current generated by the TEG device 16 can be transmitted to the substrate 14 (e.g., by way of bonding wires) and to the electrical components 18 by way of conductive traces of the substrate 14. For example, in some embodiments, the package 1 can include sensor dies, such as one or more of temperature sensors, optical sensors, pressure sensors, humidity or moisture sensors, and/or motion sensors. The package 1 can also include a processor or microcontroller die to process signals transduced by the sensor dies and a communications die to wirelessly transmit and/or receive processed data to and/or from an external computing device. The package 1 can be used in a variety of operational environments. For example, the first thermally conductive element 10 of the package 1 can be attached to a steam pipe, or to a tailpipe of an automobile, to measure various parameters of these systems. The second thermally conductive element 12 can be exposed to ambient air. The TEG device 16 can generate electrical current based on the temperature difference ΔT between the steam pipe or tailpipe and ambient air. The package 1 can thereby provide electrical power to the electrical components 18, directly or indirectly by way of a battery, without requiring an external power source.
In some embodiments, the heat source 22 can comprise a hot steam pipe and the second heat source 32 can comprise a cold water pipe. Accordingly, one of the so-called “heat sources” is in fact cold compared to the other. The first element 10 transfers heat from the first heat source 22 to the first side 31 of the TEG 16. The second element 12 similarly transfers heat from the second side 33 of the TEG 16 to a second thermal interface surface 25 between the second element 12 and the second heat source 32. The temperature difference ΔT between the first side 31 and the second side 33 of the TEG device 16 can generate electrical current to provide power to the electrical components 18 on the substrate 14.
It should be appreciated that the package 1 can be connected to any suitable device(s) that create a thermal gradient (e.g., a temperature difference ΔT) across the TEG device 16. In some embodiments, as in
Unless otherwise noted, the features of
Although disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. In addition, while several variations have been shown and described in detail, other modifications, which are within the scope of this disclosure, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the present disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the aspects that follow.
Number | Date | Country | |
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62464995 | Feb 2017 | US |