WO2016164695A1

WO2016164695A1 - Thermoelectric component and method of making same

Info

Publication number: WO2016164695A1
Application number: PCT/US2016/026601
Authority: WO
Inventors: Kaoru Ueno; Hilda OATLEY; Kei Yoshida; Hiroki HABARA
Original assignee: Nitto Denko Corporation
Priority date: 2015-04-09
Filing date: 2016-04-08
Publication date: 2016-10-13

Abstract

Described herein is a method for making a thermoelectric component, the method comprising orienting alternating sheets of metal and semiconductors at an inclination angle by overlapping disposition of plural components. Also described herein are thermoelectric components made according to these methods and thermoelectric devices incorporating the same.

Description

THERMOELECTRIC COMPONENT AND METHOD OF MAKING SAME

Inventors:

Kauro Ueno, Hilda Oatley, Kei Yoshida, and Hiroki Habara FIELD OF INVENTION

[0001] This disclosure relates to thermoelectric components, a fabrication method of the thermoelectric component and a thermoelectric device.

BACKGROUND

[0002] Thermoelectric generation is a technology for directly converting thermal energy into electric energy using the Seebeck effect, i.e. a phenomenon in which an electromotive force is generated in proportion to a temperature difference created between opposite ends of a substance. However, often times a thermoelectric component may not be flexible.

[0003] Thus there is a need to enhance the utility of thermoelectric components by reducing the thickness of the component, and/or increasing the flexibility of the component. In addition, since there are such multitudes of uses, there is a need for a manufacturing method to cheaply and rapidly manufacture these flexible thermoelectric components.

SUMMARY OF THE INVENTION

[0004] Methods for making thermoelectric components may help to improve the flexibility of the thermoelectric component. Some embodiments include orienting alternating sheets of metal and semiconductors at an inclination angle by overlapping disposition of plural components.

[0005] In some embodiments, a method of preparing a device as described above, is provided. The method comprises: providing plural alternating metal and semiconductor layers; orienting the alternating layers at an inclination angle relative a structural substrate; and affixing the oriented alternating layers on the structural substrate. In some embodiments, the method further comprises removing the oriented layered laminate from the structural substrate in the affixed orientation. In some embodiments, orienting the alternating layers comprises offset layering individual planar segments at an inclination angle relative to the structural substrate. In some embodiments, orienting the alternating layers comprises offset layering by wrapping the alternating layer around the structural substrate.

[0006] These and other embodiments are described in more detail herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 depicts an elevational schematic view showing an embodiment of a thermoelectric power generation component as well as the direction in which the first and second electrodes oppose each other, the direction in which a temperature difference is to be applied, and an inclination angle Θ.

[0008] FIG. 2 is a top view of an embodiment of a thermoelectric generation component.

[0009] FIG. 3 depicts an elevational view of an embodiment of a thermoelectric power generation component during the method of making the same.

[0010] FIG 4 depicts an elevational view of overlapping adjacent alternating metal and semiconductor element portions.

[0011] FIG. 5 depicts an elevational schematic of a thermoelectric generation component disposed between a high temperature body and a lower temperature body.

[0012] FIG. 6 depicts a schematic of an embodiment of a thermoelectric device including a thermoelectric component described herein

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Disclosed herein are thermoelectric components, or components for converting thermal energy to electric energy.

[0014] Some embodiments include a component for converting thermal energy to electric energy comprising a first side and a second side opposite to the first side. The first side is in thermal contact with a higher temperature body, the second side is in thermal contact with a lower temperature body. The distance between the first side and the second side is less than about 100 μιη. The thermoelectric component further comprises a first layer of a first thickness, comprising a first compound, and at least a second layer of a second thickness, comprising a second compound. These first and second layers are parallel to each other and in contact with each other, and are oriented at an inclination angle to a plane defined by the first side. The thermoelectric component is in electrical communication with a circuit or electrical storage device. In some embodiments, the first layer comprises a compound, e.g., a metal, which can be chosen from Cu, Ni, and Al. In some embodiments, the second layer comprises a thermoelectric compound which can be Bi-Te, Bi-Te-Sb, Pb-Ge- Se, PEDOT. In some embodiments, the ratio of the first thickness to the second thickness can be between 9: 1 and 3:7. In some embodiments, the inclination angle of the layers relative to the plane of the surface of the multilayer device can be an oblique angle. In some embodiments, the oblique angle can be between about 0.5° and about 10°.

[0015] As shown in FIG. 1 , an embodiment provides a thermoelectric component 10 comprising a planar thermoelectric layered composite 15. The planar composite has a first side 12 and a second side 14 opposite the first side. The first side 12 is in thermal contact with a higher temperature body 16, and the second side is in thermal contact with a lower temperature body 18. In some embodiments, the layered composite comprises at least one metal layer 20 and a second layer of a thermoelectric material 22.

[0016] Some layered composites comprise plural alternating layers. For example, the layered composite can comprise staggered alternating first layers and second layers, such as alternating metal layer 20 and thermoelectric material layers 22 depicted in FIG. 1 . In such an arrangement, the layer composite may comprise two or more distinct tiles, wherein each tile includes a first layer comprising a first compound or element and a second layer or element. The tiles may be arranged in a staggered configuration. In a staggered configuration, the first layer of one tile partially overlaps with the second layer of an adjacent tile. The overlap may be about 20-80%, about 30-70%, about 40-60%, about 20-40%, about 30-50%, about 40-60%, about 50-70%, or about 60-80% of the area of the tile, the first layer, or the second layer, or may be any area in a range bounded by any of these values. The staggered structure may result in the first layers and the second layers being oriented at the inclination angle with respect to a plane defined by the first side.

[0017] As shown in FIG. 1 , a first electrode 24 and a second electrode 26 can be in electrical communication with the layered composite 15. The layered composite 15 can include plural metal layers 20 in alternating contact with plural semiconductor layers 22. In some embodiments, a temperature difference between the higher temperature body and the lower temperature body may be 1 °C or greater, 5 °C or greater, 50 °C or greater, 100 °C or greater, or 200 °C or greater. A temperature differential between the higher and lower temperature bodies may be any temperature as long as the temperature does not cause melting of components or current interference in the thermoelectric device or module containing the described component.

[0018] As shown in FIG. 2, the thermoelectric component can be generally planar, alternating inclined layers of metal 20 and thermoelectric material 22, electrically connected to electrodes 24 and 26.

[0019] For any thermoelectric component, the distance between the first side and the second side can be any suitable distance, such as less than about 500 μιη, less than about 250 μιη, less than about 150 μιη, less than about 100 μιη, less than about 75 μιη, about 5-500 μιη, about 5-250 μιη, about 5-150 μιη, about 5-100 μιη, about 5-75 μιη, or any distance in a range bounded by any of these values.

[0020] For any thermoelectric component, particularly a planar thermoelectric component, the first layer of the thermoelectric component, or the layer comprising the first compound or element, can comprise a metal, such as a transition metal, including Cu, Ni, and/or a mixture thereof, or Cu, Ni, Al, and/or a mixture thereof. In some embodiments, the first layer may comprise copper metal, e.g. a copper ribbon.

[0021] For any thermoelectric component, particularly a planar thermoelectric component, the second layer, or the layer comprising the second compound or element, can be a thermoelectric material. In some embodiments the thermoelectric material can be an inorganic compound. In some embodiments, the inorganic compound may have a suitable crystallinity. In some embodiments, the second compound or element can comprise bismuth (Bi), antimony (Sb), tellurium (Te), and/or selenium (Se). For example, a formula of the inorganic compound may be A₂M₃ (wherein, A is Bi and/or Sb, and M is Te and/or Se). For example, when a Bi- Te based thermoelectric material is used, thermoelectric performance at around room temperature may be excellent. In some embodiments the inorganic compound can be Bi-Te, Bi-Te-Sb, or Pb-Ge-Se. In some embodiments, the inorganic compound can be Bi₂Te₃, and/or Bio.5Sb1.5Te3.

For some thermoelectric components, the second layer can be a coating deposited upon the first layer. In some embodiments, the second layer compound can be an organic compound. In some embodiments, the second compound can be a hole injection material, such as an optionally substituted compound selected from the following: a polythiophene derivative such as poly(3,4-ethylenedioxythiophene (PEDOT)/polystyrene sulphonic acid (PSS), a benzidine derivative such as N, N, N', N'-tetraphenylbenzidine or poly(N, N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), a triphenylamine or phenylenediamine derivative such as N,N'-bis(4-methylphenyl)- N,N'-bis(phenyl)-1 ,4-phenylenediamine, 4,4',4"-tris(N-(naphthylen-2-yl)-N- phenylamino)triphenylamine, an oxadiazole derivative such as 1 ,3-bis(5-(4- diphenylamino)phenyl-1 ,3,4-oxadiazol-2-yl)benzene, a polyacetylene derivative such as poly(1 ,2-bis-benzylthio-acetylene), and a phthalocyanine metal complex derivative such as phthalocyanine copper.

[0022] In some embodiments, the ratio of the first thickness to the second thickness (metal/thermoelectric semiconductor) can be within the range of about 1 -2.5 (e.g. a first thickness of 35 μιη of Cu and a second thickness of 35 μιη for Bi₂Te₃ is a ratio of about 1 , and a first thickness of 35 μιη of Cu and a second thickness of 15 μιη for Bi₂Te₃ is a ratio of about 2.5), about 0.1 , about 0.5-0.7, about 0.6-0.8, about 0.7-0.9, about 0.8-1 , about 0.9-1 .1 , about 1 -1 .2, about 1 .1 -1 .3, about 1 .2-1 .4, about 1 .3-1 .5, about 1 .4-1.6, about 1 .5-1 .7, about 1 .6-1 .8, about 1 .7-1 .9, about 1 .8-2, about 1 .9-2.1 , about 2-2.2, about 2.1 -2.3, about 2.2-2.4, about 2.3-2.5, about 2.4-2.6, about 2.5-2.7, about 2.6-2.8, about 2.7-2.9, about 2.8-3, about 2.9-3.1 , about 3-3.2, about 3.1 -3.3, about 3.2-3.4, about 3.3-3.5, about 3.4-3.6, about 3.5-3.7, about 3.6-3.8, about 3.7- 3.9, about 3.8-4, about 3.9-4.1 , about 4-4.2, about 4.3-4.5, about 4.4-4.6, about 4.5- 4.7, about 4.6-4.8, about 4.7-4.9, about 4.8-4, about 4.9-5.1 , or any ratio in a range bounded by any of these values

[0023] A thermoelectric component may include first and second electrodes. The first and second electrodes may be disposed to oppose each other. In some embodiments, the thermoelectric component can comprise a laminate, such as a staggered laminate, that is interposed between and electrically connected to the first and second electrodes.

[0024] In some embodiments, the laminate can have a structure in which the lamination surfaces of a semiconductor layer surface and a metal layer surface are inclined at an inclination angle Θ of about 0.5°-20°, about 2-15°, about 5-15°, about 8-12°, about 3.5-12 °, about 10°, 1 -2°, about 1 -3°, about 2-4°, about 3-5°, about 4-6°, about 5-7°, about 6-8°, about 7-9°, about 8-10°, about 9-1 1 °, about 10-12°, about 1 1 - 13°, about 12-14°, about 13-15°, about 14-16°, about 15-17°, about 16-18°, about 17-19°, about 18-20°, about 19-21 °, about 20-22°, or any angle in a range bounded by any of these values, with respect to the direction in which the electrodes of a pair oppose each other, or with respect to the plane formed by the first or second side of the thermoelectric component. In some embodiments, the thermoelectric component can be disposed on a support plate or oriented in relation or in a direction perpendicular to the direction in which the electrodes of a pair oppose each other, as indicated by arrow 28. A temperature difference may be applied in the direction perpendicular to the surface of the support plate, as indicated by arrow 30, so that electric power is obtained through the pair of electrodes. In some embodiments, the inclination angle of the layers relative to the plane of the surface of the planar thermoelectric component can be an oblique angle. In some embodiments, the oblique angle can be between about 0.5° and about 10° relative the surface plane of the planar laminate.

[0025] Referring to FIG. 4, in another embodiment, a method of preparing a device as described above, is provided, the method comprising providing plural alternating metal 20 and semiconductor 22 layers; orienting the alternating layers at an inclination angle Θ relative a structural substrate 40; affixing the oriented alternating layers on the structural substrate; and removing the oriented layered laminate from the structural substrate in the affixed orientation. In another embodiment, orienting the alternating layers comprises offset layering individual planar segments at an inclination angle relative the structural substrate. In some embodiments, orienting the alternating layers comprises offset layering by wrapping the alternating layer around the structural substrate.

[0026] FIGs. 5-6 depict an embodiment of a thermoelectric device including the above described thermoelectric component 10.

[0027] FIG. 5 depicts the thermoelectric component 10 disposed in a plane substantially perpendicular to the direction of the heat differential between higher temperature body 16 and the lower temperature body 18. The thermoelectric element 10, having electrodes 24 and 26 electrically connected on opposite ends of the composite thermoelectric component 10, is disposed in thermal communication with higher temperature body 16. In some embodiments, the higher temperature body 16 can be a first conduit or reservoir for passing or contacting or thermally communicating a thermally conducting media to the thermoelectric component 10. In some embodiments, the thermally conducting media can be a gas or a liquid. In some embodiments, the liquid can be water. In some embodiments, the higher temperature body conduit can be any thermally conductive material. In some embodiments, the thermally conductive material can be metal. In some embodiments, the thermally conductive material can be a molten salt. In some embodiments, the conduit can be a metal pipe passing the higher temperature thermally conductive media, e.g., water, therethrough. Disposed on the second side of the composite thermoelectric component 10 is the lower temperature body 18. In some embodiments, a second conduit can coaxially receive the first conduit therein, defining an annulus 32 between the first conduit and the second conduit. Colder water passes through the annulus 32 such that the thermoelectric component 10 is disposed between the high temperature body 16 and the lower temperature body 18.

[0028] In some embodiments, one of the first electrode and the second electrode may be electrically connected to a power supply or electrically connected to the outside of a thermoelectric module, for example, to an electric device that consumes or stores electric power, such as a battery for example.

[0029] In some embodiments, the method includes providing a metal layer and a semiconductor coating. In some embodiments, the metal layer can be one or more of the metals previously described, e.g., copper. In some embodiments the semiconductor coating can be one or more of the semiconductor materials previously described, e.g., Bi-Te.

[0030] In some embodiments, the second compound, e.g., the semiconductor material described above, can be formed upon the metal surface, e.g., by vapor deposition methods— such as chemical vapor deposition (CVD) or physical vapor deposition (PVD)— laminating, pressing, rolling, soaking, melting, gluing, sol-gel deposition, spin coating, dip coating, bar coating, slot coating, brush coating, sputtering, thermal spraying— including flame spray, plasma spray (DC or RF), or high velocity oxy-fuel spray (HVOF)— atomic layer deposition (ALD), cold spraying, or aerosol deposition. In one embodiment, the second material is dip coated on a metal ribbon. In some embodiments, at least a portion of the second compound coating can be removed from the surface of the first or metal compound. In some embodiments, the at least a portion of the second compound removed can form the longitudinal edge of the coated metal ribbon. In some embodiments, the second compound can be incorporated into the surface of the substrate, e.g., at least partially embedded within the surface.

[0031] In some embodiments, orienting the layered laminate can include offset layering individual planar segments at an angle relative the structural substrate, surfaces of the thermoelectric component 10, perpendicular to the temperature differential and/or perpendicular to the orientation of the first and second electrodes. As shown in FIG. 4, in some embodiments, the amount of overlap "d" by the first segment, e.g., the metal layer 22, overlapping or projecting upon the second segment, e.g., the thermoelectric semiconductor 20, a distance "d" over the width "w" of the segments, can be about 10% to about 90% of the width w of the second segment, when the width of the segment is between about 2 mm to about 4 mm if the tape thickness is about 40 μιη. In some embodiments, the overlap by the first segment can be about 70% to 90% of the width of the second segment, when the width is about 2 mm to about 4 mm.

[0032] In some embodiments, orienting the layered laminate includes offset layering the composite layer by wrapping the composite layer around the structural substrate. FIG. 3 illustrates one such arrangement in which alternating layers of metal layer 20 and thermoelectric material 22 are spiral-wrapped around substrate 40, which is cylindrical in shape. The alternating layers are then covered with a layer 35, which may be a thermoconductive material that facilitates the movement of heat in the direction of arrow 30 through thermoelectric component 10 and into cylindrical substrate 40 or opposite the direction of arrow 30 out of cylindrical substrate 40 and through thermoelectric component 10.

[0033] In some embodiments, a first or substrate rod can be positioned in parallel to a second or threaded dispensing rod. In some embodiments, the substrate rod and the dispensing rod concurrently rotate, such that a thermoelectric semiconductor/metal bilayer dispensed from the dispensing rod or spool can be spirally wrapped around the substrate rod at a distance d relative the width W of the bilayer. Pitch is the distance from the crest of one thread to the next. By varying the pitch on the dispensing rod, the amount of overlap of the ribbon width can be tuned. In some embodiments, the pitch can be between about 1 mm and about 3 mm, e.g., about 2 mm. In one embodiment, the rotation and thread pitch were ascertained to provide about a 50% spiral overlap of the ribbon.

[0034] In some embodiments, the method includes orienting the layered metal and semiconductor layers at an inclination angle. In some embodiments, orienting the layered laminate can include offset layering the individual planar segments at an angle relative to the structural substrate. In some embodiments, orienting the layered laminate includes offset layering the laminated layer by wrapping the laminate around the structural substrate.

[0035] In some embodiments, the method includes affixing the oriented layered laminate at an angle relative the substrate surface plane. In some embodiments, affixing the oriented layered laminate includes applying an adhesive element to the oriented layered laminate to retain the positioned metal and semiconductor layers as overlapped. In some embodiments, the adhesive element can comprise a thermoconductive polymer. In some embodiments, the thermoconductive polymer can be a polyimide. In some embodiments, affixing the oriented layered laminate includes depositing the plural laminate layers as desired upon a softened thermoplastic substrate and hardening the softened substrate to retain the so positioned layers in their position.

[0036] Various thermoplastic materials may be used. In some embodiments, the thermoplastic element comprises acrylic, nylon, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polycarbonate, polyethersulfone (PES), polysulfone, polyether, polyester, polylactic acid, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate (EVA), ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE), or combinations thereof. In some embodiments, the thermoplastic element comprises polytetrafluoroethylene (PTFE). In some embodiments, the thermoplastic element comprises PTFE commercially available as Teflon, from Du Pont). In some embodiments, the thermoplastic element comprises PES commercially available as Udel from Union Carbide. In some embodiments, the thermoplastic comprises ETFE commercially available as Tefzel. In some embodiments, the thermoplastic element comprises polycarbonate, PES, ETFE, EVA, and any combination thereof.

[0037] The T_embeci temperature that the thermoplastic material is heated up to sufficiently soften the thermoplastic material depends on the material itself. All thermoplastics by definition have a melting point T_m, above which the polymer exists as a liquid at atmospheric pressure. Many thermoplastics also exhibit a glass transition temperature T_g (sometimes called a softening point), above which the polymer becomes increasingly soft or pliable with increasing temperature. According to some methods disclosed herein, heat is applied to the thermoplastic element such that the temperature of the thermoplastic element reaches a point at which the thermoplastic element is soft enough for the particles to be embedded into it given the pressure that will be applied. In some embodiments, T_embeci equals or exceeds the T_g of the thermoplastic element but is equal to or less than the T_m of the thermoplastic element. In some embodiments, Tembed is at or near the T_m of the thermoplastic element. In some embodiments, T_embeci is within 100 °C of the T_m of the thermoplastic element. In some embodiments, T_embeci is within 80 °C of the T_m of the thermoplastic element. In some embodiments, T_embeci is within 60 °C of the T_m of the thermoplastic element. In some embodiments, T_embeci is within 40 °C of the T_m of the thermoplastic element. In some embodiments, T_embeci is within 30 °C of the T_m of the thermoplastic element. In some embodiments, T_embeci is within 20 °C of the T_m of the thermoplastic element. In some embodiments, T_embeci is within 10 °C of the T_m of the thermoplastic element. In some embodiments, Tembed is within 5 °C of the T_m of the thermoplastic element. In some embodiments, T_embed is between about 50 °C and about 300 °C. In one embodiment, the thermoplastic substrate can be EVA softened to about 80° C for about 5 minutes.

[0038] In some embodiments, the method includes removing the affixed oriented layered laminate from the substrate surface. In some embodiments, removing the affixed layered laminate from the substrate surface can include detaching the affixed layered laminate from the substrate surface. In some embodiments, the substrate surface can comprise the higher or lower temperature body. In some embodiments, wherein the substrate surface can be a portion of the higher or lower temperature body, the affixed layer can remain on the substrate surface. In some embodiments, the affixed layered laminate can be cut along the longitudinal axis of the substrate. In some embodiments, the cut layered laminate is removed from contacting the substrate.

[0039] The following embodiments are contemplated:

Embodiment 1 . A component for converting thermal energy to electric energy comprising: a. a first side, and a second side opposite the first side, wherein the first side is in thermal contact with a higher temperature body and the second side is in thermal contact with a lower temperature body,

wherein the distance between the first side and the second side is less than about 100 μιη;

b. a first layer of a first thickness, comprising a first compound or element; and

c. a second layer of a second thickness, comprising a second compound or element that is different from the first compound or element;

wherein the first layer and the second layer are parallel to each other and in contact each other, and are oriented at an inclination angle with respect to a plane defined by the first side;

wherein the component is in electrical communication with a circuit or electrical storage device.

Embodiment 2. The component of Embodiment 1 , wherein the first layer comprises Cu, Ni, or Al.

Embodiment 3. The component of Embodiment 2, wherein the first layer comprises copper metal.

Embodiment 4. The component of Embodiment 1 , 2, or 3, wherein the second layer comprises a compound having Bi and Te; a compound having Bi, Te, and

Sb; a compound having Pb, Ge, and Se; or PEDOT.

Embodiment s. The component of Embodiment 1 , 2, 3, or 4, wherein the second layer comprises an inorganic compound of Bi and Te which is dispersed in an organic hole injection material.

Embodiment 6. The component of Embodiment 4 or 5, wherein the second layer comprises Bi₂Te₃.

Embodiment 7. The component of Embodiment 5 or 6, wherein the organic hole injection material comprises poly(3,4-ethylenedioxythiophene).

Embodiment s. The component of Embodiment 1 , 2, 3, 4, 5, 6, or 7, wherein the ratio of the first thickness to the second thickness is between about 1 to about 2.5. Embodiment 9. The component of Embodiment 1 , 2, 3, 4, 5, 6, 7, or 8, wherein the inclination angle of the layers relative to the plane of the surface of the multilayer device is an oblique angle.

Embodiment 10. The component of Embodiment 9, wherein the oblique angle is between about 0.5° to about 20°.

Embodiment 1 1 . An energy storage system comprising the component of

Embodiment 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10 and an electrical storage device.

Embodiment 12. An electrical device comprising the energy storage system of

Embodiment 1 1 .

[0040] It has been discovered that embodiments of the thermoelectric components and methods for making the same described herein improve the flexibility and/or thinness of the thermoelectric component. These benefits are further shown by the following examples, which are intended to be illustrative of the embodiments of the disclosure, but are not intended to limit the scope or underlying principles in any way.

Examples

Process of ribbon roll method and Preparation of TE compound coated metal tape (ribbon)

[0041] This can be carried out either by preparation of metal tape followed by TE compound coating or by TE coating on a metal sheet roll followed by slitting. TE compound can be coated on one side or both sides. In some cases, it is important that the tape edge (long side) be bare. One advantage, then, of coating a large metal sheet roll and then slitting the roll into the desired width is ensuring that the tape edge is bare.

Making the TE/metal ribbon

Electrochemical deposition of TE compound (e.g., Bi₂Te₃)

Pretreatment of Cu foil

[0042] Copper foil about 1 .25 cm (0.5 inches) x 5 cm (2.0 inches) and a thickness of 30 - 40 μιη (Copper tape, 3M, Minneapoli, MN, USA) was sonicated in an acetone bath for about 5 minutes to degrease and then dried for about 1 hour to complete dryness under ambient air conditions. The cleaned foil was immersed in about 200 ml of 0.1 M H₂S04 for about 5 s to remove surface oxide. After that, the cleaned foil was immersed in about 20 ml of 4 M CuCl₂ solution for about 20 s to roughen the surface and then rinsed with about 200 ml of deionized (Dl) water to remove residual CuCI₂ solution from the foil. The etched Cu foil was then immersed in 0.1 M H₂S0₄ for about 10 s to remove CuCI₂ residue and Cu(OH)₂ on the foil surface. Finally, the foil was washed with about 200 ml Dl water thoroughly.

Deposition of Bi₂Te

[0043] An electrolyte solution for electrochemical coating upon the metal foil surface was prepared by dissolving 6.3 g Bi(N0₃)3 (0.013 M) and 2.4 g TeO (0.015 M) in about 1000 ml of 1 M HN0₃ aqueous solution. Electrochemical deposition of the solution upon the cleaned foil was performed on a potentiostat in the above solution (about 150 ml_) at constant cathodic current density (1 .8 - 3.1 mA/cm²) and constant charge amount, for about 15-30 minutes. A platinum gauze (5 cm x 5 cm) was used for a counter electrode. After the deposition, the foil was rinsed with excess water (about 200 ml) and dried in air under ambient temperature and atmospheric conditions to substantial dryness, i.e., about 30 minutes.

[0044] Each piece was trimmed along the longitudinal edge a minimal amount, e.g. , less than about 1 mm, with a razor blade to remove a portion of the deposited Bi/Te material from the longitudinal edge of the Cu foil, while retaining a substantial portion of the deposited Bi/Te material coating, e.g., along the top and/or bottom surfaces, and/or so expose the metal foil.

Casting of TE compound on Cu foil

[0045] TE (e.g. , Bi₂Te₃) powder was dispersed in 5 wt% PEDOT:PSS aqueous solution at a weight ratio (TE powder: PEDOT-PSS solution) of 1 :0 - 1 :2. About 25 ml of the above PEDOT-PSS:TE precursor solution were added by drops onto a 30 cm X 30 cm Cu sheet and dried at room temperature and ambient atmosphere. Or a mixture of PEDOT:PSS and Bi₂Te₃ powder was coated on a Cu sheet (35 μιη). Final TE thickness after drying was 15 - 35 μιη. The TE coated Cu foil was cut along the longitudinal edges, exposing the Cu along the longitudinal edges. Winding on rod

[0046] A wrapping mechanism was constructed where a substrate rod was placed in parallel to a threaded rod, the rod having a threaded dispenser or spool to travel along the substrate rod, e.g., the spool dispenser was in threaded engagement with the threaded rod to move longitudinally down the threaded rod in parallel to a rotating substrate rod for receipt of a dispersed ribbon thereon, the dispersed ribbon being overlapped a selected amount by the thread count of the spool dispenser. A first roll of TE/Cu ribbon was placed into a spool dispenser/winding mechanism adjacent to the rod-like substrate, such that as the spool moved down the threaded spool holder, the TE/Cu ribbon was wrapped around the substrate rod as the spool moved parallel, longitudinally down the substrate rod axis. The TE/Cu ribbon was wrapped around the rod-like substrate at about x rpm as the ribbon spool was concurrently displaced along the longitudinal axis by the threaded spool holder. The thread count, about one thread every 2 mm (12.5 threads per inch) provided an equidistant and/or constant overlapping of about 50% of the width of the ribbon along the longitudinal axis of the substrate rod.

Cut and open

[0047] After winding, the TE/Cu tape was covered with a single strip of polyimide adhesive tape placed length-wise to hold or affix the positioned TE/Cu wound tape. The affixed, wound TE/Cu tape was cut along the rod axis to obtain tilted TE/Cu multilayer on polyimide tape.

Modularization

[0048] The TE coated Cu foil made as described above was cut into 1/4" x 1 /8" pieces with a razor blade. A sheet of EVA (1 " x 3", and 450 μιη thick), used as a substrate, was placed on a 9 cm X 9 cm sheet of polyethylene terephthlate (PET), the sheets were heated to about 70 °C on a hot plate set at "Medium." At this temperature, EVA becomes slightly sticky so it is easy to position, place and align the small TE/Cu pieces.

[0049] A first Cu ribbon (a strip of about 50 mm X 3.2 mm), the future terminal (first) electrode, was placed on a 2.5 cm X 7.5 cm sheet of ethylene-vinyl acetate (EVA) (where purchased). The sheet had been previously made by hot pressing EVA pellets (Sigma-Aldrich, St. Louis, MO, USA). The first piece of TE/Cu coated foil made as described above, was placed longitudinally along the length of the Cu ribbon, on the edge of Cu terminal, overlapping the Cu ribbon by about 2 mm. A second piece of TE/Cu was put on a first TE/Cu piece with about a 50% width overwrap. Additional TE/Cu pieces were placed in a similar manner as just described. After 10 pieces of TE/Cu were aligned on EVA, another Cu ribbon terminal was placed atop the last TE/Cu piece, about 5 mm of the Cu ribbon extending onto the last TE/Cu piece. A second sheet of EVA film (same size as substrate) was put on top of aligned TE/Cu pieces to dispose the aligned TE/Cu pieces between the two EVA sheets. Since EVA is slightly sticky at about 70 °C, the two EVAs (bottom and top) can temporally hold the TE/Cu pieces and Cu terminals as positioned. A second PET film sheet was put on top of EVA for the next step of vacuum lamination.

[0050] The above described PET/EVA/TE/EVA/PET construct was laminated under vacuum (less than 3 kPa) at 80 °C at a pressure of about 100 kPa. At first the laminator was evacuated (less than 3 kPa) for 5 minutes at 80 °C, and then pressed at 100 kPa for 12 minutes. After lamination, the sample was cooled down to RT under ambient atmospheric conditions. At this point, EVA thickness was still about 450 μιη, and the size was almost same as the initial thickness and width, length.

[0051] To make the EVA thinner, the laminated sample (PET/EVA/TE/EVA/PET) was heated to 80 °C under ambient atmosphere for about 1 minute and pressed at about 0.5 MPa for 1 minute. Then, the sample was pressed at about 1 .25 MPa at the same temperature for 1 minute, followed by pressing 2.5 MPa at the same temperature for 1 minute. With this process, the final thickness (EVA/TE/EVA without PET) was about 250 μιη.

Thermoelectric device including the thermoelectric component

[0052] The above described PET/EVA/TE/EVA/PET construct was laminated under vacuum (less than 3 kPa) at 80 °C at a pressure of about 100 kPa. At first the laminator was evacuated (less than 3 kPa) for 5 minutes at 80 °C, and then pressed at 100 kPa for 12 minutes. After lamination, the sample was cooled down to RT under ambient atmospheric conditions. At this point, EVA thickness was still about 450 μιη, and the size was almost same as the initial thickness and width, length. [0053] To make the EVA thinner, the laminated sample (PET/EVA/TE/EVA/PET) was heated to 80 °C under ambient atmosphere for about 1 minute and pressed at about at about 1 .25 MPa at the same temperature for 1 minute, followed by pressing 2.5 MPa at the same temperature for 1 minute. With this process, the final thickness (EVA/TE/EVA without PET) was about 250 urn.

[0054] Consistent with the schematic depicted in FIGs. 4 and 5, a thermoelectric device was constructed. A 10 layer composite thermoelectric component, made as described in above, was disposed approximately in the middle upon the outer surface of a 12 inch section of copper pipe having an inner diameter of about 1 inch. A polycarbonate sleeve having a thickness of about 1/8 of an inch and an inner diameter of about 1 .5 inches, was coaxially positioned over the thermoelectric component and held in place by annular rubber stoppers to define a concentric and coaxial annulus. The annular space was communicated via inlets to the outside to pass cold water, at about 40 °C, through the space. Hot water, at about 80 °C was concurrently passed through the internal copper conduit, creating a temperature differential of about 40 °C. An ammeter/voltmeter was connected to the first and second electrodes. The ammeter registered a voltage of about 0.3 mV generated by the thermoelectric device for a 1 cm long thermoelectric component.

[0055] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0056] The terms "a," "an," "the" and similar referents used in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of any claim. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0057] Groupings of alternative elements or embodiments disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

[0058] Certain embodiments are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, the claims include all modifications and equivalents of the subject matter recited in the claims as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is contemplated unless otherwise indicated herein or otherwise clearly contradicted by context.

[0059] In closing, it is to be understood that the embodiments disclosed herein are illustrative of the principles of the claims. Other modifications that may be employed are within the scope of the claims. Thus, by way of example, but not of limitation, alternative embodiments may be utilized in accordance with the teachings herein. Accordingly, the claims are not limited to embodiments precisely as shown and described.

Claims

Embodiments:

1 . A component for converting thermal energy to electric energy comprising: a. a first side, and a second side opposite the first side, wherein the first side is in thermal contact with a higher temperature body and the second side is in thermal contact with a lower temperature body,

2. The component of Claim 1 , wherein the first layer comprises Cu, Ni, or

Al.

3. The component of Claim 2, wherein the first layer comprises copper metal.

4. The component of Claim 1 , 2, or 3, wherein the second layer comprises a compound having Bi and Te; a compound having Bi, Te, and Sb; a compound having Pb, Ge, and Se; or PEDOT.

5. The component of Claim 1 , 2, 3, or 4, wherein the second layer comprises an inorganic compound of Bi and Te which is dispersed in an organic hole injection material.

6. The component of Claim 4 or 5, wherein the second layer comprises

Bi₂Te₃.

7. The component of Claim 5, wherein the organic hole injection material comprises poly(3,4-ethylenedioxythiophene).

8. The component of Claim 1 , 2, 3, 4, 5, 6, or 7, wherein the ratio of the first thickness to the second thickness is between about 1 to about 2.5.

9. The component of Claim 1 , 2, 3, 4, 5, 6, 7, or 8, wherein the inclination angle of the layers relative to the plane of the surface of the multilayer device is an oblique angle.

10. The component of Claim 9, wherein the oblique angle is between about 0.5° and about 20°.

1 1 . An energy storage system comprising the component of Claim 1 , 2, 3, 4, 5, 6, 7, 8, 9, or 10 and an electrical storage device.

12. An electrical device comprising the energy storage system of claim 1 1 .