Thermoelectric generators (TEGs) are solid state devices that can convert a temperature difference (or heat flux) into electrical energy through a phenomenon called the Peltier effect. TEGs have a variety of applications but not yet fully realized. As such, there exists a need for improved TEGs and fabrication processes.
Aspects of the present disclosure are related to flexible thermoelectric devices, which can be used for cooling or heating. Examples of systems, methods of making and uses of the thermoelectric devices are disclosed.
In one aspect, among others, a flexible thermoelectric generator (TEG) comprises vertical voids in a foam block, thermoelectric (TE) legs in the vertical voids, and conductive connectors coupled to TE legs. The foam block can comprise the vertical voids, wherein the vertical voids extend from a top surface to a bottom surface of the foam block. The foam block can comprise horizontal voids, wherein each horizontal void can extend into the foam block a depth as measured from either the top surface of the foam block or the bottom surface of the foam block, wherein the horizontal voids do not extend completely from the top surface of the foam block to the bottom surface of the foam block. Each horizontal void can extend a distance along the top surface or the bottom surface of the foam block, and wherein at least one end of each horizontal void overlaps a vertical void. Each end of at least one of the horizontal voids can overlap a vertical void. Each TE leg can be contained in a vertical void, wherein the TE leg can have a first surface at a first end of the TE leg and a second surface at a second end of the TE leg, wherein the first end is opposite the second end of the TE leg. The entire TE leg except for the first surface and the second surface can be in direct contact with the foam block, wherein the first surface of the TE leg can be level with the bottom of a horizontal void extending into the top surface of the foam block, and wherein the second surface of the TE leg can be level with the bottom of a horizontal void extending into the bottom surface of the foam block. Each conductive connector can be layered on the bottom of a horizontal void, wherein at least one end of each conductive connector is coupled to a first surface or a second surface of at least one of the TE legs. A thickness of each conductive connector can be less than the depth of the horizontal void.
In one or more aspects, the flexible TEG can comprise heat spreading material blocks, wherein each heat spreading material block is placed in the horizontal void on top of the conductive connector present in the horizontal void. A bottom surface of each heat spreading material block can be in direct contact with at least the conductive connector present in the horizontal void and a top surface of each heat spreading material block can be level with either the bottom surface of the foam block or the top surface of the foam block. The flexible TEG can comprise a heat sink, wherein the heat sink can be in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and can be in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the heat sink. The heat sink can form an outer layer of the flexible TEG. The flexible TEG can comprise a compressive material layer, wherein the compressive material layer can be in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and is in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the compressive material layer. The compressive material layer can form an outer layer of the flexible TEG opposite of the heat sink.
In various aspects, the flexible TEG can comprise a compressive material layer, wherein the compressive material layer can be in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and can be in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the compressive material layer. The heat compressive material layer can form an outer layer of the flexible TEG. At least one of the horizontal voids can extend to an edge of the foam block and wherein the conductive connector in contact with the bottom surface of the horizontal void that extends to the edge of the foam block can extend a distance past the edge of the foam block and can be configured to couple to a power source. At least one additional horizontal void can extend to the edge of the foam block and wherein the conductive connector in contact with the bottom surface of the horizontal void that extends to the edge of the foam block can extend a distance past the edge of the foam block and can be configured to couple to a power source.
In some aspects, the foam block can comprises patterned scoring on the top surface, bottom surface, or both the top and the bottom surface of the foam block. The foam block can comprise a polymer, a textile, or a combination of a polymer and a textile thereof. The polymer can be an open cell or a closed cell polymer. The foam layer can be a flexible printed circuit board. The conductive connectors can comprise a conductive film or a filament of metals, a printed material composed of a metallic ink or an ink-polymer composite, a polymer film, or any combination thereof. At least one of the TE legs can be an N-type TE leg or a P-type TE leg. The heat spreading material block can comprise a metal, a polymer composite, a metal or graphene coated material, a carbon or graphene-based thermally conductive films, a highly conductive polymer film, a soft rubbery material that can be loaded with ceramic particles or materials, or any combination thereof. The heat sink can comprise a metal, a polymer composite, a metal or graphene coated material, a carbon or graphene-based thermally conductive films, a highly conductive polymer film, a soft rubbery material that can be loaded with ceramic particles or materials, or any combination thereof. The compressive material layer can comprise: a polymer, a textile, or a combination of a polymer and a textile. The total resistance across all the conductive connectors and contact resistance between the conductive connectors and the TE legs can be less than the total resistance of the TE legs. A total resistance across all the conductive connectors and contact resistance between the conductive connectors and the TE legs can be less than a total resistance of the TE legs.
In another aspect, a system comprises a plurality of the flexible TEG devices. At least one of the flexible TEG devices of the plurality of TEG devices can be coupled to a power source, and wherein each of the TEG devices of the plurality of TEG devices can be coupled to at least one other TEG device of the plurality of TEG devices. At least two of the TEG devices can be coupled in series. At least two of the TEG devices can be coupled in parallel. A cushion or a mattress can comprise one or more flexible TEG devices or a system of flexible TEG devices.
In another aspect, a method of manufacturing a flexible TEG device comprises forming vertical voids in a foam block, wherein the vertical voids extend from a top surface to a bottom surface of the foam block; forming horizontal voids in the foam block; inserting a plurality TE legs into a plurality of the vertical voids; and connecting pairs of TE legs in the plurality of TE legs with conductive connectors. Each horizontal void can extend into the foam block a depth as measured from either the top surface of the foam block or the bottom surface of the foam block, wherein the horizontal voids do not extend completely from the top surface of the foam block to the bottom surface of the foam block. Each horizontal void can extend a distance along the top surface or the bottom surface of the foam block, wherein at least one end of each horizontal void can overlap a vertical void. Each end of at least one of the horizontal voids can overlap a vertical void. A single TE leg can be inserted per vertical void, wherein the TE leg has a first surface at a first end of the TE leg and a second surface at a second end of the TE leg, wherein the first end is opposite the second end of the TE leg. The entire TE leg except for the first surface and the second surface can be in direct contact with the foam block, wherein the first surface of the TE leg can be level with the bottom of a horizontal void extending into the top surface of the foam block, and wherein the second surface of the TE leg can be level with the bottom of a horizontal void extending into the bottom surface of the foam block. Each conductive connector can be layered on the bottom of a horizontal void. At least one end of each conductive connector can be coupled to a first surface or a second surface of a TE leg and the other end of each conductive connector can be coupled to a first surface or a second surface of a different TE leg in the plurality of TE legs. A thickness of each conductive connector can be less than the depth of the horizontal void.
In one or more aspects, the method can comprise coupling a heat spreading material block to the foam block. Each heat spreading material block can be placed in the horizontal void on top of the conductive connector present in the horizontal void. A bottom surface of each heat spreading material block can be in direct contact with the heat spreading block and a top surface of each heat spreading material block can be level with either the bottom surface of the foam block or the top surface of the foam block. The method can comprise coupling a heat sink to the foam block. The heat sink can be in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and can be in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the heat sink. The heat sink can form an outer layer of the flexible TEG. The method can comprise coupling a compressive material layer to the foam block. The compressive material layer can be in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and can be in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the compressive material layer. The compressive material layer can form an outer layer of the flexible TEG opposite of the heat sink.
In various aspects, at least one of the horizontal voids can extend to the edge of the foam block and the conductive connector in contact with the bottom surface of the horizontal void that extends to the edge of the foam block can extend a distance past the edge of the foam block and can be configured to couple to a power source. At least one additional horizontal void can extend to the edge of the foam block and the conductive connector in contact with the bottom surface of the horizontal void that extends to the edge of the foam block can extend a distance past the edge of the foam block and can be configured to couple to a power source. The method can comprise etching or cutting a pattern on the top surface, bottom surface, or both the top and the bottom surface of the foam block. The foam block can comprise a polymer, a textile, or a combination of a polymer and a textile thereof. The conductive connectors can comprise a conductive film or a filament of metals, a printed material composed of a metallic ink or an ink-polymer composite, a polymer film, or any combination thereof. At least one of the TE legs can be an N-type TE leg or a P-type TE leg.
In some aspects, the heat spreading block can comprise a metal, a polymer composite, a metal or graphene coated material, a carbon or graphene-based thermally conductive films, a highly conductive polymer film, a soft rubbery material that can be loaded with ceramic particles or materials, or any combination thereof. The heat sink can comprise a metal, a polymer composite, a metal or graphene coated material, a carbon or graphene-based thermally conductive films, a highly conductive polymer film, a soft rubbery material that can be loaded with ceramic particles or materials, or any combination thereof. The compressive material layer can comprise a polymer, a textile, or a combination of a polymer and a textile. The TE legs can be coupled to the conductive connectors such that a total resistance across all the conductive connectors and contact resistance between the conductive connectors and the TE legs can be less than a total resistance of the TE legs.
Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.
Further aspects of the present disclosure will be readily appreciated upon review of the detailed description of its various embodiments, described below, when taken in conjunction with the accompanying drawings.
Before the present disclosure is described in greater detail, it is to be understood that this disclosure is not limited to particular embodiments described, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described.
All publications and patents cited in this specification are cited to disclose and describe the methods and/or materials in connection with which the publications are cited. All such publications and patents are herein incorporated by references as if each individual publication or patent were specifically and individually indicated to be incorporated by reference. Such incorporation by reference is expressly limited to the methods and/or materials described in the cited publications and patents and does not extend to any lexicographical definitions from the cited publications and patents. Any lexicographical definition in the publications and patents cited that is not also expressly repeated in the instant application should not be treated as such and should not be read as defining any terms appearing in the accompanying claims. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosure. Further, the dates of publication provided could be different from the actual publication dates that may need to be independently confirmed.
As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. Any recited method can be carried out in the order of events recited or in any other order that is logically possible.
It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.
Where a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g. ‘about x, y, z, or less' and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”.
It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.
It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1% to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.
As used herein, “about,” “approximately,” “substantially,” and the like, when used in connection with a numerical variable, can generally refers to the value of the variable and to all values of the variable that are within the experimental error (e.g., within the 95% confidence interval for the mean) or within +/−10% of the indicated value, whichever is greater. As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” can mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.
Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of physics, engineering (e.g. electrical engineering and the like), chemistry, and the like, which are within the skill of the art. Such techniques are explained fully in the literature.
Thermoelectric generators (TEGs) are solid-state devices that can convert a temperature difference (or heat flux) into electrical energy through a phenomenon called the Peltier effect. TEGs have a variety of applications but not all have yet been fully realized. Commercially available TEGs are rigid and very expensive for applications that require the device be employed over a large surface area. As such, there exists a need for improved TEGs and fabrication processes.
With that said, described herein are flexible TEG devices that can be used for energy harvesting and solid-state heating and cooling applications. Also described herein are manufacturing processes that can be scalable and thus provide economic production of the flexible TEG (or TEC) devices described herein. Other compositions, compounds, methods, features, and advantages of the present disclosure will be or become apparent to one having ordinary skill in the art upon examination of the following drawings, detailed description, and examples. It is intended that all such additional compositions, compounds, methods, features, and advantages be included within this description, and be within the scope of the present disclosure.
Flexible TEG Devices and Systems
Discussion of the flexible TEG (or TEC) device begins with
The flexible TEG 100 can further include a heat spreading material block 170, wherein each heat spreading block 170 can be placed in the horizontal void on top of the conductive connector 140 present in the horizontal void, wherein a bottom surface of each heat spreading material block 170 is in direct contact with at least the conductive connector 140 and a top surface of each heat spreading material block is level with either the bottom surface of the foam block 110 or the top surface of the foam block 110.
The flexible TEG 100 can further include a heat sink 160, wherein the heat sink 160 can be in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block 110 and can be in direct contact with the heat spreading material blocks 170 that are level with the surface of the foam block 110 that is in direct contact with the heat sink 160, wherein the heat sink 160 can form an outer layer of the flexible TEG 100.
The flexible TEG 100 can further include a compressive material layer 150, wherein the compressive material layer 150 is in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block 110 and is in direct contact with the heat spreading material blocks 170 that are level with the surface of the foam block 110 that is in direct contact with the compressive material layer 150, wherein the compressive material layer 150 can form an outer layer of the flexible TEG 100 opposite of the heat sink 160.
In some embodiments of the flexible TEG 100, at least one of the horizontal voids can extend to the edge of the foam block 110 and wherein the conductive connector 140 that is in contact with the bottom surface of the horizontal void that extends to the edge of the foam block 110 can extend a distance past the edge of the foam block 110 and can be configured to couple to a power source. In some embodiments of the flexible TEG 100, at least one additional horizontal void can extend to the edge of the foam block 110 and wherein the conductive connector 140 in contact with the bottom surface of the horizontal void that extends to the edge of the foam block 110 can extend a distance past the edge of the foam block 110 and can be configured to couple to a power source.
In some embodiments of the flexible TEG device 100, the foam block 110 can further include patterned scoring on the top surface, bottom surface, or both the top and the bottom surface of the foam block. In some embodiments, the pattern can be a Kirigami styled pattern. The pattern can be a geometric pattern. Cut dimensions and/or shaping can allow for improved and/or altered bending and/or folding of the device. This can allow the device to conform around and/or onto planar and curvilinear surfaces.
The foam block can be made of any suitable materials. Suitable materials can include, but are not limited to, polymers (including, but not limited to, polymer gels, closed or open foam materials), textiles (including, but not limited to, nonwoven textiles, woven textiles, knits, textiles that include spacer fabrics and/or multilayered structures. In some aspects, multiple layers can be coupled or otherwise attached together using, e.g., an adhesive material.
The conductive connectors can be made of any suitable materials. Suitable materials can include but are not limited to, conductive film or filaments of metals (including, but not limited to, Ag, Cu, Au, and combinations thereof). Additionally, printed materials composed of metallic ink or ink-polymer composites can be directly printed and/or patterned directly on the structure supporting the thermoelectric legs in the polymer films and/or on polymer films that can be placed between the thermoelectric legs. The conductive connector can be linear or straight between the ends of the conductive connector. The conductive connector can be curved between the ends of the conductive connector. The conductive connector can be angled at one or more points, e.g., zig-zagged between the ends of the conducive connector. The conductive connector can be any other crimped shape that can provide stretchability of the interconnect without increasing the resistance of the device while bent.
As previously discussed, the flexible TEG device 100 can include TE legs 130. In some embodiments, at least one of the TE legs 130 is an N-type TE leg. In some embodiments, at least one of the TE legs 130 is a P-type TE leg. In some aspects, the flexible TEG device 100 includes both N-type and P-type TE legs. In aspects, the N-type and P-type legs can be put in series. Each leg (and thus each vertical void) can be spaced from each other by a distance in any direction. In some embodiments, the spacing in each direction can be the same (e.g., homogenous or uniform). In some embodiments, the spacing in at least two directions can be different from each other (e.g., heterogeneous or non-uniform). In some embodiments, the spacing in at least two directions can be the same. In some embodiments, the spacing in at least two directions can be different (also heterogeneous). The distance between any two TE legs 130 can range from about 0.1 mm to about 50 mm. In some aspects, the resistance of the interconnect and joint (e.g., a soldering joint) can be less than that of a corresponding thermoelectric leg.
As previously discussed, the flexible TEG device 100 can include heat spreading material blocks 170. The heat spreading material blocks 170 can be made of a suitable material. Suitable materials can include but are not limited to, materials that have a thermal conductivity of greater than about 1 W/m/K (air) or greater than that of the material supporting the thermoelectric legs. This can include metals, polymer composites (e.g., metal or carbon flake), metal or graphene coated materials, carbon or graphene based thermally conductive films, highly conductive polymer films, and/or soft rubbery materials that can be loaded with ceramic particles or materials. Other suitable materials will be appreciated by those of ordinary skill in the art in view of this description.
As previously discussed, the flexible TEG device 100 can include a heat sink 160. The heat sink 160 can be made of a suitable material. Suitable materials can include but are not limited to, materials that have a thermal conductivity of greater than about 1 W/m/K (air) or greater than that of the material supporting the thermoelectric legs. This can include metals, polymer composites (e.g., metal or carbon flake), metal or graphene coated materials, carbon or graphene based thermally conductive films, highly conductive polymer films, soft rubbery materials that can be loaded with ceramic particles or materials. These materials can also be structured to permit heat convection and further enhance heat removal. These materials can also have photonic or emissive properties that improve the radiative removal of heat. Other suitable materials will be appreciated by those of ordinary skill in the art in view of this description.
As previously discussed, the flexible TEG device 100 can include a compressive material layer 150. The compressive material layer 150 can be made of a suitable material. Suitable materials can include but are not limited to, polymers (including but not limited to polymer sheets, rubber sheets, polymer gels, closed and open cell foam materials), textiles (including but not limited to nonwoven materials, knits, and woven materials). Using materials with low thermal conductivity (e.g., less than 1 W/m/K, less than 0.8 W/m/K, less than 0.5 W/m/K, or less than 0.1 W/m/K) can assist in the cooling or heating operations of the TEG device 100. For example, the use of open foams and/or textiles can reduce heat leakage from the hot side to the cold side of the TEG device 100. Fully dense materials can make it easier for heat to leak back to the cold side. In some aspects, the material can be compressed itself while not impeding the compression of an underlying material. The compressive material layer 150 should also be flexible allowing for bending and movement of the TEG device 100 during installation and use. The compressive material layer 150 can provide electrical isolation so that the conductive elements (e.g., TE legs 130 and conductive connectors 140) to avoid electrical shorts in the TEG device 100.
To operate the flexible TEG device 100 described herein as a solid state cooling TEG (or TEC), the flexible TEG 100 can be configured such that the total resistance across all the conductive connectors 140 and any soldering contacts and contact resistance between the conductive connectors 140 and the TE legs 130 is less than the total resistance of the TE legs 130. The materials of the conductive connectors and/or leg spacing can be chosen to achieve such a total resistance.
The thermoelectric cooling phenomenon can be more prominent than joule heating (the I2R term in equation 1 below
In one embodiment, copper foil of about 1 mm thickness can be used as the conductive connector 140. The conductive connectors 140 can have a 10 mm length and about a 2 mm width. The legs can be spaced homogenously from about 5 mm to about 20 mm apart. This can be measured from the end of each leg or from the middle of each leg. In other implementations, the conductive connectors 140 can be provided by, e.g., preprinted flexible circuit boards or printed electronics (e.g., using direct jet, screen printing, etc.) In some embodiments, a standard solder paste can be used to connect the TE legs 130. In some embodiments, a thermoplastic polyurethane film can be used as an adhesive support layer around the conductive connectors. A thermally conductive silicone material can be used as the heat spreading material block 170 as well as the compressive material layer 150. In some embodiments, a laser etched Kirigami inspired design can be scored on the top and/or bottom surface of the foam block 110. In some aspects, a Cu film can be connected to one or more TE legs and can be stabilized with an adhesive base on foam that can be included around one or more of the TE legs 130.
Also described herein are systems that can include a plurality of the flexible TEG devices 100 described herein, wherein at least one of the flexible TEG devices 100 of the plurality of TEG devices 100 can be coupled to a power source, and wherein each of the TEG devices of the plurality of TEG devices 100 can be coupled to at least one other TEG device 100 of the plurality of TEG devices 100. In some embodiments, at least two of the TEG devices 100 can be coupled in series. In some embodiments, at least two of the TEG devices 100 can be coupled in parallel. The arrangement of the flexible TEG devices 100 can be determined based upon the power and/or voltage levels during operation.
Any of the TEG devices 100 or systems thereof described herein can be incorporated into an article. In some aspects, the article can be a cushion, mattress, a garment (including but not limited to an inner garment (e.g., shirt, underwear, base layers etc.), outer garment (e.g., jackets, pants, sweaters (outer shirts), hats, gloves, etc.), shoes and shoe liners, carpets, flexible wraps for use on a subject (e.g., bandages, support wraps), flexible wraps that can be used on an inanimate object (e.g., a wrap for a beverage container, lining of a cooler or bag, etc.), and in any other article that currently uses or can use foam, a spacer fabric, 3D fabric, nonwoven, rubber or film.
Methods of Manufacturing the TEG Devices and Systems
Also described herein are methods of manufacturing the TEG devices and systems thereof described herein. In some embodiments, the method can include forming vertical voids in a foam block, wherein the vertical voids extend from a top surface to a bottom surface of the foam block; forming horizontal voids in the foam block, wherein each horizontal void extends into the foam block a depth as measured from either the top surface of the foam block or the bottom surface of the foam block, wherein the horizontal voids do not extend completely from the top surface of the foam block to the bottom surface of the foam block, wherein each horizontal void extends a distance along the top surface or the bottom surface of the foam block, wherein at least one end of each horizontal void overlaps a vertical void, wherein each end of at least one of the horizontal voids overlaps a vertical void; inserting a plurality TE legs into a plurality of the vertical voids, wherein a single TE leg is inserted per vertical void, wherein the TE leg has a first surface at a first end of the TE leg and a second surface at a second end of the TE leg, wherein the first end is opposite the second end of the TE leg, wherein the entire TE leg except for the first surface and the second surface is in direct contact with the foam block, wherein the first surface of the TE leg is level with the bottom of a horizontal void extending into the top surface of the foam block, and wherein the second surface of the TE leg is level with the bottom of a horizontal void extending into the bottom surface of the foam block; and connecting pairs of TE legs in the plurality of TE legs with conductive connectors, wherein each conductive connector is layered on the bottom of a horizontal void, wherein at least one end of each conductive connector is coupled to a first surface or a second surface of a TE leg and wherein the other end of each conductive connector is coupled to a first surface or a second surface of a different TE leg in the plurality of TE legs, wherein the thickness of each conductive connector is less than the depth of the horizontal void.
The method can further include the step of coupling a heat spreading block to the foam block, wherein each heat spreading block is placed in the horizontal void on top of the conductive connector present in the horizontal void, wherein a bottom surface of each heat spreading block is in direct contact with the heat spreading block and a top surface of each heat spreading block is level with either the bottom surface of the foam block or the top surface of the foam block.
The method can further include the step of coupling a heat sink to the foam block, wherein the heat sink is in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and is in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the heat sink, wherein the heat sink forms an outer layer of the flexible TEG.
The method can further include the step of coupling a compressive material layer to the foam block, wherein the compressive material layer is in direct contact with the top surface or the bottom surface, but not both surfaces, of the foam block and is in direct contact with the heat spreading material blocks that are level with the surface of the foam block that is in direct contact with the compressive material layer, wherein the compressive material layer forms an outer layer of the flexible TEG opposite of the heat sink.
In some embodiments, at least one of the horizontal voids extends to the edge of the foam block and wherein the conductive connector in contact with the bottom surface of the horizontal void that extends to the edge of the foam block extends a distance past the edge of the foam block and is configured to couple to a power source. In some embodiments, at least one additional horizontal void extends to the edge of the foam block and wherein the conductive connector in contact with the bottom surface of the horizontal void that extends to the edge of the foam block extends a distance past the edge of the foam block and is configured to couple to a power source. The TEG device can have one or more termination points, which are where the TEG device is coupled to a power supply. The termination point(s) can exist at any point in the TEG device so long as there is at least two TE legs in series.
The method can further include the step etching (or cutting) a pattern on the top surface, bottom surface, or both the top and the bottom surface of the foam block. This can be completed using laser etching, chemical etching, or other suitable etching (or cutting) techniques. The pattern can also be formed on the top surface, bottom surface, or both the top and bottom surface of the foam block by other manufacturing techniques such as molding based manufacturing processes or 3D printing techniques. Such techniques will be appreciated by those of ordinary skill in the art in view of the description provided herein.
In some embodiments of the flexible TEG device 100, the foam block 110 can further include patterned scoring on the top surface, bottom surface, or both the top and the bottom surface of the foam block. In some embodiments, the pattern can be a Kirigami-styled pattern. The pattern can be a geometric pattern. Cut dimensions and/or shaping can allow for improved and/or altered bending and/or folding of the device. This can allow the device to conform around and/or onto planar and curvilinear surfaces.
The foam block can be made of any suitable materials. Suitable materials can include, but are not limited to, polymers (including, but not limited to, polymer gels, closed or open foam materials), textiles (including, but not limited to, nonwoven textiles, woven textiles, knits, textiles that include spacer fabrics and/or multilayered structures. In some aspects, multiple layers can be coupled or otherwise attached together using an adhesive material. The conductive connectors can be made of any suitable materials. Suitable materials can include, but are not limited to, conductive film or filaments of metals (including, but not limited to, Ag, Cu, Au, and combinations thereof). Additionally, printed materials composed of metallic ink or ink-polymer composites that can be directly printed and/or patterned directly on the structure supporting the thermoelectric legs in the polymer films and/or on polymer films that can be placed between the thermoelectric legs.
As previously discussed, the flexible TEG device 100 can include TE legs 130. In some embodiments, at least one of the TE legs 130 is an N-type TE leg. In some embodiments, at least one of the TE legs 130 is a P-type TE leg. In some aspects, the flexible TEG device 100 includes both N-type and P-type TE legs. In some aspects the TEG leg can be composed at least partially or entirely of bismuth telluride. In some aspects, the TE leg(s) can be made of any material that can be placed in series and have an absolute Seebeck coefficient difference that is greater that zero. In some aspects, the TE legs can be a metal or organic conductor or semiconductor in ceramic or bulk form. In some aspects, the TE legs can be composed, at least partially or entirely, of an ink. Each leg (and thus each vertical void) can be spaced from each other by a distance in any direction. In some embodiments, the spacing in each direction can be the same (e.g., homogenous or uniform). In some embodiments, the spacing in at least two directions can be different from each other (e.g., heterogeneous or non-uniform). In some embodiments, the spacing in at least two directions can be the same. In some embodiments, the spacing in at least two directions can be different (also heterogeneous). The distance between any two TE legs 130 can range from 0.1 mm to 50 mm. The resistance of the interconnect and joint (e.g. a soldering joint) can be less than that of a corresponding thermoelectric leg.
As previously discussed, the flexible TEG device 100 can include heat spreading material blocks 170. The heat spreading material blocks 170 can be made of a suitable material. Suitable materials can include but are not limited to, materials that have a thermal conductivity of greater than about 1 W/m/K (air) or that of the material supporting the thermoelectric legs. This can include metals, polymer composites (e.g. metal or carbon flake), metal or graphene coated materials, carbon or graphene based thermally conductive films, highly conductive polymer films, soft rubbery materials that can be loaded with ceramic particles or materials. Other suitable materials will be appreciated by those of ordinary skill in the art in view of this description.
As previously discussed, the flexible TEG device 100 can include a heat sink 160. The heat sink 160 can be made of a suitable material. Suitable materials can include but are not limited to, materials that have a thermal conductivity of greater than about 1 W/m/K (air) or that of the material supporting the thermoelectric legs. This can include metals, polymer composites (e.g. metal or carbon flake), metal or graphene coated materials, carbon or graphene based thermally conductive films, highly conductive polymer films, soft rubbery materials that can be loaded with ceramic particles or materials. Other suitable materials will be appreciated by those of ordinary skill in the art in view of this description.
As previously discussed, the flexible TEG device 100 can include a compressive material layer 150. The compressive material layer 150 can be made of a suitable material. Suitable materials can include but are not limited to, polymers (including but not limited to polymer gels, closed and open cell foam materials), textiles (including but not limited to nonwoven materials, knits, and woven materials). In some aspects, the material can be compressed itself while not impeding the compression of an underlying material.
The method can include the step of coupling the conductive connectors and TE legs using soldering, where the ends of the conductive connective connector are soldered to the ends of the TE legs.
Now having described the embodiments of the present disclosure, in general, the following Examples describe some additional embodiments of the present disclosure. While embodiments of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit embodiments of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of embodiments of the present disclosure.
In some implementations, openings or voids can be formed between the interconnects to assist in flexibility of the device.
It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.
This application claims priority to, and the benefit of, co-pending U.S. provisional application entitled “Flexible Thermoelectric device, systems thereof, methods of making and uses thereof” having Ser. No. 62/746,883, filed Oct. 17, 2018, the entirety of which is hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/056798 | 10/17/2019 | WO | 00 |
Number | Date | Country | |
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62746883 | Oct 2018 | US |