A thermoelectric device and its fabrication method

Abstract

The present invention proposes a thermoelectric device and a preparation method thereof, which belong to the field of preparation technology. The method includes configuring raw materials for printing thermoelectric structures; using the configured raw materials for printing thermoelectric structures to print thermoelectric structures using 3D printing ink direct writing technology; configuring thermal conductive materials, thermal insulating materials, heat absorbing materials, and reflective materials, and using the configured thermal conductive materials, thermal insulating materials, heat absorbing materials, and reflective materials to print thermal conductive structures, thermal insulating structures, heat absorbing structures, and reflective structures using 3D printing ink direct writing technology; assembling the 3D printed thermoelectric structures, thermal conductive structures, thermal insulating structures, heat absorbing structures, and reflective materials into thermoelectric devices. In addition, the present invention also proposes a thermoelectric device prepared by the above method. The present invention simplifies the manufacturing process and reduces the waste of raw materials, can manufacture fine structures, and has a relatively broad application prospect. All structures in this application are prepared and formed using 3D printing technology.

Description

Technical Field

[0001] This invention belongs to the technical field of novel energy harvesting structure design and its fabrication process, and particularly relates to a thermoelectric device and its fabrication method. Background Technology

[0002] With climate change and population growth, people's daily energy needs are increasing, but Earth's resources are finite. Therefore, it is necessary to develop new energy sources to meet future energy demands. Thermal energy is a clean and ubiquitous energy source. Using thermoelectric conversion technology, temperature differences can be converted into voltage differences, collecting waste heat generated in the natural environment and human activities, which will be a huge energy source.

[0003] Traditional thermoelectric generator manufacturing is a challenging and tedious process, typically employing techniques such as hot pressing, spark plasma sintering, and zone melting. These processes usually involve high temperatures and are complex, consuming significant energy and time. The sintered structures are also blocky and rigid, making it difficult to create intricate and complex structures and wasting substantial amounts of raw materials, hindering the widespread manufacturing and application of thermoelectric power generation. Therefore, to achieve high-precision three-dimensional structures, simplify the manufacturing process, and enable multi-material bonding, additive manufacturing technology has emerged as a highly promising processing technology. Additive manufacturing, often referred to as 3D printing, is a method for rapidly prototyping complex geometries. It involves depositing raw materials layer by layer, with process parameters determined by computer-controlled algorithms. Because it requires minimal rework, waste is negligible, and it is applicable to a wide variety of materials—theoretically, various materials can be configured into rheological inks and printed into complex structures—significantly reducing the manufacturing difficulty of thermoelectric devices and increasing structural complexity.

[0004] There are currently few publicly reported technologies for 3D printing of thermoelectric materials. The main potential problems include: 1. The manufacture of thermoelectric devices requires multiple materials, such as N-type thermoelectric materials, P-type thermoelectric materials, and electrode materials. Achieving 3D printing of thermoelectric devices requires multi-material collaborative printing, which is quite difficult; 2. Direct writing technology for 3D printing ink is a good way to print functional materials. Using this technology requires configuring the functional materials into rheological printable inks. The proportions of various materials in the thermoelectric device need to be adjusted to meet printing requirements, requiring continuous adjustment and improvement; 3. The ability to achieve three-dimensional structures is an advantage of 3D printing. However, during the printing process, collapse may occur at suspended points due to the ink not solidifying in time. Therefore, the successful printing of three-dimensional structures also requires careful design. Summary of the Invention

[0005] The purpose of this invention is to provide a thermoelectric device and its fabrication method. A novel structure is achieved through different structural layers of 3D printing to improve the output performance of the thermoelectric structure. By using additive manufacturing with direct ink writing through 3D printing, the thermoelectric material is configured into printable ink, avoiding the cumbersome process of traditional thermoelectric device manufacturing. A refined new structure is designed, solving the technical problems of application defects and material waste in the traditional process in the prior art.

[0006] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0007] A method for fabricating a thermoelectric device includes the following steps:

[0008] Step S1: Configure the raw materials for thermoelectric structure printing, which include support material, N-type 3D printing thermoelectric ink, and P-type 3D printing thermoelectric ink;

[0009] Step S2: Using the configured thermoelectric structure printing raw materials, the thermoelectric structure is printed using 3D printing ink direct writing technology; the thermoelectric structure includes a support structure, an N-type planar thermoelectric structure, a P-type thermoelectric planar structure, a three-dimensional N-type thermoelectric leg, a three-dimensional P-type thermoelectric leg, and an electrode connection part;

[0010] Step S3: Perform heat treatment on the 3D-printed thermoelectric structure;

[0011] Step S4: Configure the thermally conductive material and use the configured thermally conductive material to print the thermally conductive structure using 3D printing ink direct writing technology;

[0012] Step S5: Configure the thermal insulation material and use the configured thermal insulation material to print the thermal insulation structure using 3D printing ink direct writing technology;

[0013] Step S6: Configure the heat-absorbing material and use the configured heat-absorbing material to print the heat-absorbing structure using 3D printing ink direct writing technology;

[0014] Step S7: Configure the reflective material and use the configured reflective material to print the reflective structure using 3D printing ink direct writing technology;

[0015] Step S8: Assemble the 3D-printed thermoelectric structure, thermally conductive structure, thermally insulating structure, thermally absorbing structure, and reflective material into a thermoelectric device.

[0016] Further, step S1 includes the following steps:

[0017] Step S11: Prepare the support material: Mix polydimethylsiloxane (PDMS1700) and crosslinking agent at a mass ratio of 10:1 to obtain the support material; and transfer it to the barrel required for 3D printing.

[0018] Step S12: Preparation of epoxy resin base liquid: 2-Ethyl-4-methyl-1H-imidazolium-1-propionitrile (EMIP) is used as a catalyst, accounting for 1% by mass; polypropylene glycol diglycidyl ether (PPGDGE) and bisphenol F diglycidyl ether (BPFDGE) are uniformly mixed in a 1:1 mass ratio to form liquid epoxy resin, accounting for 60.4% by mass; methyl hexahydrophthalic anhydride (MHHPA) is used as a curing agent, accounting for 38.6% by mass; the catalyst, liquid epoxy resin and curing agent are uniformly mixed to obtain epoxy resin base liquid;

[0019] Step S13: Prepare N-type 3D printing thermoelectric ink: using bismuth telluride (Bi2Te) 2.7 Se 0.3 As N-type thermoelectric powder, the mass ratio of N-type thermoelectric powder to epoxy resin base liquid is 5:1, and volatile diluent n-butyl acetate is added for dilution; the mixture is then used in a ball mill at a speed of 400 r / min for 4 h to ensure uniform mixing of the thermoelectric ink, thus obtaining N-type 3D printing thermoelectric ink; the N-type thermoelectric ink is then transferred to the barrel required for 3D printing and degassed using a vacuum stirring degassing machine.

[0020] Step S14: Prepare P-type 3D printing thermoelectric ink: Use antimony telluride Sb2Te3 as P-type thermoelectric powder, and make the mass ratio of P-type thermoelectric powder to epoxy resin base liquid 6:1. Add volatile diluent n-butyl acetate for dilution; use a ball mill at a speed of 400 r / min for 4 h to mix the thermoelectric ink evenly and obtain P-type 3D printing thermoelectric ink; transfer the P-type thermoelectric ink to the barrel to be used for 3D printing, and use a vacuum stirring degassing machine for degassing treatment.

[0021] Further, step S2 includes the following steps:

[0022] Step S21: Print 7 support structures on the glass substrate using support material; each support structure is 35mm long, 1.5mm wide, and 1.3mm high. The support structures are printed evenly on the glass substrate with a 6mm gap between each other along their long sides.

[0023] Step S22: Print an N-type planar thermoelectric structure using N-type 3D printing thermoelectric ink; the N-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high; the N-type planar thermoelectric structure is printed in the gap of the support structure, and the long side of the N-type planar thermoelectric structure is perpendicular to the long side of the support structure; in the direction perpendicular to the long side of the support structure, the N-type planar thermoelectric structure and the P-type thermoelectric planar structure are printed alternately in the gap of the support structure; in the direction parallel to the long side of the support structure, the N-type planar thermoelectric structure and the P-type thermoelectric planar structure are printed alternately in the gap of the support structure, and the N-type planar thermoelectric structure and the P-type thermoelectric planar structure are spaced one support structure width apart, i.e., 1.5mm apart;

[0024] Step S23: Print a P-type planar thermoelectric structure using P-type 3D printing thermoelectric ink; the P-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high; the P-type planar thermoelectric structure is printed in the gap of the support structure, and the long side of the P-type planar thermoelectric structure is perpendicular to the long side of the support structure; in the direction perpendicular to the long side of the support structure, the P-type planar thermoelectric structure and the N-type thermoelectric planar structure are printed alternately in the gap of the support structure; in the direction parallel to the long side of the support structure, the N-type planar thermoelectric structure and the P-type thermoelectric planar structure are printed alternately in the gap of the support structure.

[0025] Step S24: Print N-type thermoelectric legs using N-type 3D printing thermoelectric ink; the N-type thermoelectric legs are 2mm long, 2mm wide, and 1mm high; the N-type thermoelectric legs are printed on top of the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the supporting structure. The N-type thermoelectric legs and P-type thermoelectric legs are printed alternately on both sides of the supporting structure. The P-type thermoelectric legs 22 and N-type thermoelectric legs 23 in the gap of the supporting structure form a Π-shaped structure with the P-type planar thermoelectric structure 21 or N-type planar thermoelectric structure 24 below.

[0026] Step S25: Print P-type thermoelectric legs using P-type 3D printing thermoelectric ink; N-type thermoelectric legs are 2mm long, 2mm wide, and 1mm high; P-type thermoelectric legs are printed on top of the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the support structure, and P-type thermoelectric legs and N-type thermoelectric legs are printed alternately on both sides of the support structure.

[0027] Step S26: Print the electrode connection part using N-type 3D printed thermoelectric ink. The electrode connection part is 5.5mm long, 2mm wide, and 0.3mm high. The electrode connection part includes a top electrode and a bottom electrode. Print the top electrode above the support structure, so that the top electrode spans the support structure and connects the N-type thermoelectric legs and P-type thermoelectric legs on both sides of the support structure, so that it forms a Π-type structure with the N-type thermoelectric legs and P-type thermoelectric legs. Print the bottom electrode on the substrate, so that the bottom electrode connects the N-type planar thermoelectric structure and P-type planar thermoelectric structure on each row of edges to form a series connection.

[0028] Further, step S4 includes the following steps:

[0029] Step S41: The thermal conductive material is composed of polydimethylsiloxane (PDMS184) and boron nitride; the polydimethylsiloxane (PDMS184) is mixed at a mass ratio of 70% and the boron nitride is mixed at a mass ratio of 30% and stirred evenly to obtain the thermal conductive material, and the thermal conductive material is transferred to the material cylinder required for 3D printing;

[0030] Step S42: Using the prepared thermally conductive material and 3D printing ink direct writing technology, print multiple cuboid thermally conductive structures with a length of 35mm, a width of 6mm, and a height of 2mm; perform heat treatment at 70 degrees Celsius for 1 hour on the 3D printed cuboid thermally conductive structures.

[0031] Further, step S5 includes the following steps:

[0032] Step S51: The thermal insulation material is composed of silica aerogel and PVA aqueous solution. The silica aerogel has a particle size of 800 mesh and a mass percentage of 10%, while the PVA aqueous solution has a mass percentage of 90%, wherein the PVA aqueous solution is made by dissolving 12.5% ​​PVA in water at 90 degrees Celsius. The silica aerogel and PVA aqueous solution are mixed and stirred evenly to prepare the thermal insulation material, which is then transferred to the material cylinder required for 3D printing.

[0033] Step S52: Using the prepared thermal insulation material and 3D printing ink direct writing technology, print multiple cuboid thermal insulation structures with a length of 35mm, a width of 6mm, and a height of 2mm; perform heat treatment at 70 degrees Celsius for 1 hour on the 3D printed cuboid thermal insulation structures.

[0034] Further, step S6 includes the following steps:

[0035] Step S61: The heat-absorbing material is composed of carbon black and polydimethylsiloxane (PDMS184). The polydimethylsiloxane (PDMS184) is mixed with carbon black at a mass ratio of 91.5% and stirred evenly to obtain the heat-absorbing material. The heat-absorbing material is then transferred to the material cylinder required for 3D printing.

[0036] Step S62: Using the prepared heat-absorbing material and 3D printing ink direct writing technology, print multiple cuboid heat-absorbing structures with a length of 35mm, a width of 6mm, and a height of 0.3mm; heat-treat the 3D-printed cuboid heat-absorbing structures at 70 degrees Celsius for 1 hour.

[0037] Further, step S7 includes the following steps:

[0038] Step S71: The reflective material is composed of silica aerogel and PVA aqueous solution; wherein the silica aerogel has a particle size of 800 mesh and a mass ratio of 10%, and the PVA aqueous solution has a mass ratio of 90%, wherein the PVA aqueous solution is made by dissolving 12.5% ​​PVA in water at 90 degrees Celsius; the silica aerogel and PVA aqueous solution are mixed and stirred evenly to prepare the reflective material, and the reflective material is transferred to the material cylinder required for 3D printing;

[0039] Step S72: Using the prepared reflective material and 3D printing ink direct writing technology, print multiple cuboid reflective structures with a length of 35mm, a width of 6mm, and a height of 0.3mm; perform heat treatment at 70 degrees Celsius for 1 hour on the 3D printed cuboid reflective structures.

[0040] Further, step S8 includes the following steps:

[0041] The 3D-printed thermally conductive and thermally insulating structures are placed side by side and alternately. A thermoelectric structure is placed above the thermally conductive and thermally insulating structures. The thermally conductive and thermally insulating structures are both located directly below the supporting structure. A heat-absorbing structure and a reflective structure are placed above the thermoelectric structure. The heat-absorbing and reflective structures are placed side by side and alternately, with the heat-absorbing structure connected to the top electrode of the thermoelectric structure and the reflective structure located at the interval of the top electrode, thus forming a thermoelectric device.

[0042] Furthermore, the present invention also proposes a thermoelectric device prepared by a method for preparing thermoelectric devices, wherein the thermoelectric device includes a reflective and heat-absorbing layer, a thermoelectric structure, and a heat-conducting and heat-insulating layer.

[0043] Furthermore, the thermally conductive and thermally insulating layer is composed of a thermally conductive structure and a thermally insulating structure; multiple thermally conductive structures and multiple thermally insulating structures are placed side by side and alternately along the long side;

[0044] The thermoelectric structure consists of a P-type planar thermoelectric structure, P-type thermoelectric legs, N-type thermoelectric legs, an N-type planar thermoelectric structure, a support structure, a bottom electrode, and a top electrode. Multiple support structures are placed side-by-side at intervals along their long sides. Each support structure is 35mm long, 1.5mm wide, and 1.3mm high, with a 6mm gap between them. The P-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high; the N-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high; the P-type thermoelectric legs are 2mm long, 2mm wide, and 1mm high; and the N-type thermoelectric legs are also 2mm long, 2mm wide, and 1mm high. The P-type and N-type planar thermoelectric structures are alternately placed in the gaps between the support structures, and the width of the long side of each P-type and N-type planar thermoelectric structure is exactly equal to the width of the gap between the support structures. The long sides of the P-type and N-type planar thermoelectric structures are perpendicular to the long sides of the support structures, and they are arranged in several rows.

[0045] The P-type thermoelectric leg and the N-type thermoelectric leg are located above the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the support structure. The N-type thermoelectric leg and the P-type thermoelectric leg are alternately arranged on both sides of the support structure. The P-type thermoelectric leg and the N-type thermoelectric leg in the gap of the support structure form a Π-shaped structure with the P-type planar thermoelectric structure or the N-type planar thermoelectric structure below.

[0046] The bottom electrode connects the edge N-type planar structure and P-type planar structure of each row to form a series connection; the top electrode spans the support structure and connects the P-type thermoelectric leg and N-type thermoelectric leg on both sides of the support structure, so that it forms a Π-type structure with the N-type thermoelectric leg and P-type thermoelectric leg.

[0047] A thermoelectric structure is placed above the heat-conducting and heat-insulating layer, so that both the heat-conducting and heat-insulating structures are located directly below the supporting structure.

[0048] A reflective and heat-absorbing layer is placed on top of the thermoelectric structure; the reflective and heat-absorbing layer is composed of heat-absorbing structures and reflective structures, with multiple heat-absorbing structures and multiple reflective structures placed side by side and alternately; the heat-absorbing structure is connected to the top electrode of the thermoelectric structure, and the reflective structure is located at the interval between the two top electrodes.

[0049] Compared with the prior art, the present invention has the following beneficial technical effects:

[0050] 1) This invention enables the rapid fabrication of thermoelectric devices using 3D printing ink direct writing technology, overcoming the drawbacks of traditional manufacturing processes such as cumbersome operation, excessive raw material waste, and difficulty in manufacturing fine structures; 2) The thermally conductive and insulating layers designed in this invention can transfer the planar temperature difference on the skin side to the hot and cold ends of the thermoelectric device, establishing a temperature difference on one side of the plane and thus improving output; 3) The heat-absorbing and reflective layers designed in this invention can absorb and reflect sunlight, thereby increasing the temperature of the hot end of the thermoelectric device and decreasing the temperature of the cold end, establishing a three-dimensional temperature difference and thus improving output; 4) The overall structure of this invention, combined with the temperature difference on one side of the skin plane and the three-dimensional temperature difference through absorption and reflection of sunlight, achieves the goal of multi-segment temperature difference, improving the output performance of wearable thermoelectric devices. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This invention relates to a 3D-printed thermoelectric device.

[0053] Figure 2 (a) is a printed diagram of the heat-conducting structure of the present invention, (b) is a printed diagram of the heat-insulating structure of the present invention, (c) is a printed diagram of the heat-absorbing structure of the present invention, and (d) is a printed diagram of the reflective structure of the present invention.

[0054] Figure 3This is a printed image of the thermoelectric device of this invention.

[0055] Figure 4 This is a schematic diagram of the overall structure of the thermoelectric device of the present invention.

[0056] Figure 5 This is a schematic diagram of the heat absorption structure and the reflection structure of the present invention.

[0057] Figure 6 This is a schematic diagram of the thermoelectric structure of the present invention.

[0058] Figure 7 This is a schematic diagram of the heat-conducting structure and heat-insulating structure of the present invention.

[0059] Figure 8 This is a schematic cross-sectional view of the thermoelectric device of the present invention.

[0060] Figure 9 This is a schematic diagram illustrating the temperature difference achieved by the thermoelectric device of the present invention and the current generated by the temperature difference.

[0061] Figure 10 The graph shows the test data for the heat-absorbing and reflective structures.

[0062] Figure 11 The graph shows the test data for the thermally conductive and thermally insulating structures.

[0063] The markings in the diagram are as follows: 1. Reflective and heat-absorbing layer; 2. Thermoelectric structure; 3. Heat-conducting and heat-insulating layer; 11. Heat-absorbing structure; 12. Reflective structure; 21. P-type thermoelectric planar structure; 22. P-type thermoelectric leg; 23. N-type thermoelectric leg; 24. N-type thermoelectric planar structure; 25. Support structure; 26. Bottom electrode; 27. Top electrode; 31. Heat-insulating structure; 32. Heat-conducting structure. Detailed Implementation

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] The present invention proposes a method for fabricating thermoelectric devices by printing different structural layers using multi-material collaborative 3D printing technology. The method includes the following steps:

[0066] Step S1: Configure the raw materials for thermoelectric structure printing, which include support material, N-type 3D printing thermoelectric ink, P-type 3D printing thermoelectric ink, and epoxy resin base liquid.

[0067] Specifically, step S1 includes the following steps:

[0068] Step S11: Prepare the support material: Mix polydimethylsiloxane (PDMS1700) and crosslinking agent at a mass ratio of 10:1 to obtain the support material; and transfer it to the barrel to be used in 3D printing.

[0069] Step S12: Prepare epoxy resin base liquid: Use 2-ethyl-4-methyl-1H-imidazolium-1-propionitrile (EMIP) as catalyst, with a mass ratio of 1%; use polypropylene glycol diglycidyl ether (PPGDGE) and bisphenol F diglycidyl ether (BPFDGE) mixed uniformly in a 1:1 mass ratio as liquid epoxy resin, with a total mass ratio of 60.4%; use methyl hexahydrophthalic anhydride (MHHPA) as curing agent, with a mass ratio of 38.6%. Mix the catalyst, liquid epoxy resin and curing agent uniformly to obtain epoxy resin base liquid.

[0070] Step S13: Prepare N-type 3D printing thermoelectric ink: using bismuth telluride (Bi2Te) 2.7 Se 0.3 (Particle size 1250 mesh) was used as the N-type thermoelectric powder. The mass ratio of N-type thermoelectric powder to epoxy resin base liquid was 5:1, and volatile diluent n-butyl acetate was added for dilution. The mixture was ball-milled at 400 rpm for 4 hours to ensure uniform mixing, thus obtaining the N-type 3D printing thermoelectric ink. The N-type thermoelectric ink was transferred to the barrel required for 3D printing and degassed using a vacuum stirring and degassing machine.

[0071] Step S14: Prepare P-type 3D printing thermoelectric ink: Use antimony telluride Sb₂Te₃ (particle size 1250 mesh) as the P-type thermoelectric powder, making the mass ratio of P-type thermoelectric powder to epoxy resin base liquid 6:1, and add volatile diluent n-butyl acetate for dilution. Mix using a ball mill at 400 r / min for 4 hours to ensure uniform mixing of the thermoelectric ink, obtaining the P-type 3D printing thermoelectric ink. Transfer the P-type thermoelectric ink to the barrel required for 3D printing and degas it using a vacuum stirring degassing machine.

[0072] Step S2: Using the configured thermoelectric structure printing raw materials, print the thermoelectric structure using 3D printing ink direct writing technology, such as... Figure 1 As shown, the thermoelectric structure includes a support structure, an N-type planar thermoelectric structure, a P-type planar thermoelectric structure, a three-dimensional N-type thermoelectric leg, a three-dimensional P-type thermoelectric leg, and an electrode connection portion.

[0073] Specifically, step S2 includes the following steps:

[0074] Step S21: Print 7 support structures on the glass substrate using support material; each support structure is 35mm long, 1.5mm wide, and 1.3mm high. The support structures are printed evenly on the glass substrate with a 6mm gap between each other along their long sides.

[0075] Step S22: Print an N-type planar thermoelectric structure using N-type 3D printing thermoelectric ink. The N-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high. The N-type planar thermoelectric structure is printed in the gap between the support structures, with its long side perpendicular to the long side of the support structure, and the length of the long side of the N-type planar thermoelectric structure exactly equal to the gap between the support structures. In the direction perpendicular to the long side of the support structure, N-type planar thermoelectric structures and P-type thermoelectric planar structures are printed alternately in the gap between the support structures. In the direction parallel to the long side of the support structure, N-type planar thermoelectric structures and P-type thermoelectric planar structures are printed alternately in the gap between the support structures, with a gap of one support structure width (1.5mm) between the N-type and P-type thermoelectric planar structures.

[0076] Step S23: Print a P-type planar thermoelectric structure using P-type 3D printing thermoelectric ink. The P-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high. The P-type planar thermoelectric structure is printed in the gap between the support structures, with its long side perpendicular to the long side of the support structure, and the length of the long side of the P-type planar thermoelectric structure exactly equal to the gap between the support structures. In the direction perpendicular to the long side of the support structure, P-type planar thermoelectric structures and N-type thermoelectric planar structures are printed alternately in the gap between the support structures. In the direction parallel to the long side of the support structure, N-type planar thermoelectric structures and P-type thermoelectric planar structures are printed alternately in the gap between the support structures.

[0077] Eight rows of printed N-type planar thermoelectric structures and eight rows of printed P-type planar thermoelectric structures are combined along the long side of the vertical support structure and the long side of the parallel support structure.

[0078] Step S24: Print N-type thermoelectric legs using N-type 3D printing thermoelectric ink; the N-type thermoelectric legs are 2mm long, 2mm wide, and 1mm high. The N-type thermoelectric legs are printed on top of the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the support structure. The N-type thermoelectric legs and P-type thermoelectric legs are printed alternately on both sides of the support structure. The P-type thermoelectric legs 22 and N-type thermoelectric legs 23 in the gap of the support structure form a Π-shaped structure with the P-type planar thermoelectric structure 21 or N-type planar thermoelectric structure 24 below.

[0079] Step S25: Print P-type thermoelectric legs using P-type 3D printing thermoelectric ink; N-type thermoelectric legs are 2mm long, 2mm wide, and 1mm high. P-type thermoelectric legs are printed on top of the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the support structure. P-type thermoelectric legs and N-type thermoelectric legs are printed alternately on both sides of the support structure. P-type thermoelectric legs 22 and N-type thermoelectric legs 23 in the gap of the support structure form a Π-shaped structure with the P-type planar thermoelectric structure 21 or N-type planar thermoelectric structure 24 below.

[0080] Step S26: Print the electrode connection part using N-type 3D printed thermoelectric ink. The electrode connection part includes a top electrode and a bottom electrode, with a length of 5.5mm, a width of 2mm, and a height of 0.3mm. The electrode connection part connects the N-type planar thermoelectric structure and the P-type planar thermoelectric structure. Print the top electrode above the support structure, making the top electrode span the support structure and connect the N-type thermoelectric legs and P-type thermoelectric legs on both sides of the support structure, so that it forms a Π-shaped structure with the N-type thermoelectric legs and P-type thermoelectric legs. Print the bottom electrode on the substrate, so that the bottom electrode connects the N-type planar thermoelectric structures and P-type planar thermoelectric structures at each row of edges, forming a series connection.

[0081] Step S3: Perform heat treatment on the 3D printed thermoelectric structure.

[0082] Specifically, the 3D-printed thermoelectric structure is first pretreated at 120 degrees Celsius for 2 hours, and then heat-treated at 350 degrees Celsius for 4 hours in a muffle furnace under nitrogen atmosphere.

[0083] Step S4: Configure the thermally conductive material and use the configured thermally conductive material to print the thermally conductive structure using 3D printing ink direct writing technology.

[0084] Specifically, in step S41: the thermally conductive material is composed of polydimethylsiloxane (PDMS184) and boron nitride. The slurry containing 70% PDMS184 and 30% boron nitride by mass is stirred until homogeneous to obtain the thermally conductive material. This thermally conductive material is then transferred to the cartridge required for 3D printing.

[0085] Step S42: Using the prepared thermally conductive material and 3D printing ink direct writing technology, print multiple cuboid thermally conductive structures with a length of 35mm, a width of 6mm, and a height of 2mm, such as... Figure 2 As shown in (a), the 3D-printed cuboid thermally conductive structure was heat-treated at 70 degrees Celsius for 1 hour.

[0086] Step S5: Configure the insulation material and use the configured insulation material to print the insulation structure using 3D printing ink direct writing technology.

[0087] Specifically, in step S51: the thermal insulation material is composed of silica aerogel and PVA aqueous solution. The silica aerogel has a particle size of 800 mesh and accounts for 10% by mass, while the PVA aqueous solution accounts for 90% by mass, wherein the PVA aqueous solution is made by dissolving 12.5% ​​by mass of PVA in water at 90 degrees Celsius. The silica aerogel and PVA aqueous solution are mixed and stirred evenly to prepare the thermal insulation material, which is then transferred to the material cylinder required for 3D printing.

[0088] Step S52: Using the prepared insulation material and 3D printing ink direct writing technology, print multiple cuboid insulation structures with a length of 35mm, a width of 6mm, and a height of 2mm, such as... Figure 2 As shown in (b), the 3D-printed cuboid thermal insulation structure was heat-treated at 70 degrees Celsius for 1 hour.

[0089] Step S6: Configure the heat-absorbing material and use the configured heat-absorbing material to print the heat-absorbing structure using 3D printing ink direct writing technology.

[0090] Specifically, in step S61: the heat-absorbing material is composed of carbon black and polydimethylsiloxane (PDMS184). The polydimethylsiloxane (PDMS184) is mixed at a mass ratio of 91.5% and the carbon black is mixed at a mass ratio of 8.5% to form a uniform slurry, and the heat-absorbing material is then transferred to the material cylinder required for 3D printing.

[0091] Step S62: Using the prepared heat-absorbing material and 3D printing ink direct writing technology, print multiple cuboid heat-absorbing structures with a length of 35mm, a width of 6mm, and a height of 0.3mm, such as... Figure 2 (c) The 3D-printed cuboid heat-absorbing structure was heat-treated at 70 degrees Celsius for 1 hour.

[0092] Step S7: Configure the reflective material and use the configured reflective material to print the reflective structure using 3D printing ink direct writing technology.

[0093] Specifically, in step S71: the reflective material is composed of silica aerogel and PVA aqueous solution; wherein the silica aerogel has a particle size of 800 mesh and accounts for 10% by mass, and the PVA aqueous solution accounts for 90% by mass, wherein the PVA aqueous solution is made by dissolving 12.5% ​​by mass of PVA in water at 90 degrees Celsius. The silica aerogel and PVA aqueous solution are mixed and stirred evenly to obtain the reflective material, which is then transferred to the material cylinder required for 3D printing.

[0094] Step S72: Using the prepared reflective material and 3D printing ink direct writing technology, print multiple cuboid reflective structures with a length of 35mm, a width of 6mm, and a height of 0.3mm, such as... Figure 2As shown in (d), the 3D-printed cuboid reflective structure was heat-treated at 70 degrees Celsius for 1 hour.

[0095] Step S8: Assemble the 3D-printed thermoelectric structure, thermally conductive structure, thermally insulating structure, thermally absorbing structure, and reflective material into a thermoelectric device.

[0096] Specifically, 3D-printed thermally conductive and thermally insulating structures are placed side-by-side alternately, with a thermoelectric structure placed above them. Both the thermally conductive and thermally insulating structures are positioned directly below the supporting structure. A heat-absorbing and reflective structure is placed above the thermoelectric structure; these structures are placed side-by-side alternately, with the heat-absorbing structure connected to the top electrode of the thermoelectric structure and the reflective structure positioned at the intervals between the top electrodes, forming a thermoelectric device. A physical image of the thermoelectric device is shown below. Figure 3 .

[0097] This invention also proposes a thermoelectric device prepared by the above-described thermoelectric device preparation method, such as... Figure 4-7 As shown, the thermoelectric device includes a reflective and heat-absorbing layer 1, a thermoelectric structure 2, and a thermally conductive and heat-insulating layer 3.

[0098] The thermally conductive and insulating layer 3 is composed of a thermally conductive structure 32 and a thermally insulating structure 31. Multiple thermally conductive structures 32 and multiple thermally insulating structures 31 are placed side by side and alternately along the long side.

[0099] The thermoelectric structure 2 consists of a P-type planar thermoelectric structure 21, a P-type thermoelectric leg 22, an N-type thermoelectric leg 23, an N-type planar thermoelectric structure 24, a support structure 25, a bottom electrode 26, and a top electrode 27. Multiple support structures are placed side-by-side at intervals along their long sides. Support structure 25 is 35mm long, 1.5mm wide, and 1.3mm high, with a 6mm gap between them; P-type planar thermoelectric structure 21 is 6mm long, 2mm wide, and 0.3mm high; N-type planar thermoelectric structure 24 is 6mm long, 2mm wide, and 0.3mm high; P-type thermoelectric leg 22 is 2mm long, 2mm wide, and 1mm high; and N-type thermoelectric leg 23 is 2mm long, 2mm wide, and 1mm high. P-type planar thermoelectric structure 21 and N-type planar thermoelectric structure 24 are alternately arranged in the gap of support structure 25, and the width of the long side of P-type planar thermoelectric structure 21 and N-type planar thermoelectric structure 24 is exactly equal to the width of the gap of support structure; the long side of P-type planar thermoelectric structure 21 and N-type planar thermoelectric structure 24 is perpendicular to the long side of support structure 25, and they are arranged in several rows.

[0100] P-type thermoelectric leg 22 and N-type thermoelectric leg 23 are located above the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the supporting structure. The N-type thermoelectric leg and the P-type thermoelectric leg are alternately arranged on both sides of the supporting structure. The P-type thermoelectric leg 22 and the N-type thermoelectric leg 23 in the gap of the supporting structure form a Π-shaped structure with the P-type planar thermoelectric structure 21 or the N-type planar thermoelectric structure 24 below.

[0101] The bottom electrode 26 connects the edge N-type planar structure and P-type planar structure of each row to form a series connection; the top electrode 27 spans the support structure and connects the P-type thermoelectric leg 22 and N-type thermoelectric leg 23 on both sides of the support structure, so that it forms a Π-type structure with the N-type thermoelectric leg and the P-type thermoelectric leg.

[0102] The thermoelectric structure 2 is placed above the heat-conducting and heat-insulating layer 3, so that both the heat-conducting structure and the heat-insulating structure are located directly below the supporting structure.

[0103] A reflective and heat-absorbing layer 1 is placed above the thermoelectric structure 2. The reflective and heat-absorbing layer 1 is composed of heat-absorbing structures 11 and reflective structures 12, with multiple heat-absorbing structures 11 and multiple reflective structures 12 placed side by side alternately. The heat-absorbing structures 11 are connected to the top electrode 27 of the thermoelectric structure, and the reflective structures 12 are located at the interval between two top electrodes.

[0104] Furthermore, Figure 8 This is a cross-sectional diagram of a thermoelectric device, showing the connection relationships between its various components. The heat-absorbing structure 11 absorbs sunlight to raise the temperature of the hot end, the reflective structure 12 reflects sunlight to lower the temperature of the cold end, the heat-insulating structure 31 blocks some heat conduction, and the heat-conducting structure 32 conducts heat, thus achieving the desired temperature difference. A schematic diagram of the temperature difference and current in the thermoelectric device is shown below. Figure 9 As shown, based on the principle of thermoelectric power generation, majority carriers in N-type and P-type thermoelectric materials will move from areas of high temperature to areas of low temperature. The temperature difference created by the thermoelectric device can generate... Figure 9 A continuous current.

[0105] To verify the functionality of the thermoelectric device, performance tests will be conducted on each structure below:

[0106] The performance of the printed heat-absorbing and reflective structures was tested by irradiating them with a simulated solar light source under intense sunlight. Temperature sensors were placed beneath the structures to measure temperature changes. The test results are as follows: Figure 10 As shown, the results indicate that the heat-absorbing structure can absorb sunlight to increase the temperature, while the reflective structure can reflect sunlight to decrease the temperature. The combination of the two can achieve a temperature difference.

[0107] Performance testing of the printed thermal insulation and thermal conduction structures involved heating the structures from room temperature to 70 degrees Celsius using a heating plate. Temperature sensors were placed on both structures to monitor temperature changes. The test results are as follows: Figure 11 As shown, the results indicate that the thermal insulation structure can suppress the temperature, while the thermally conductive structure can transmit the energy for temperature transfer. The combination of the two can achieve a temperature difference.

[0108] Performance testing of the planar printed thermoelectric device involved placing the printed thermoelectric structure on a heating stage at 37 degrees Celsius. Subsequently, printed heat-conducting, heat-insulating, heat-absorbing, and reflective structures were added. The device was then exposed to sunlight at a simulated solar intensity, producing a maximum output of 22mV. Due to heat diffusion, the output slowly decreased over time. In contrast, when the planar thermoelectric structure was directly heated without the addition of heat-conducting, heat-absorbing, and reflective structures, the output was zero because there was no temperature difference between the cold and hot ends. Therefore, the above results demonstrate that adding this structure can generate multiple temperature differences to improve the thermoelectric output.

[0109] For the performance testing of the 3D printed thermoelectric device, the printed thermoelectric structure was placed on a heating stage with a temperature of 37 degrees Celsius. Subsequently, a heat-conducting structure and a heat-insulating structure were added, and the test output was 25.9mV. After adding a heat-absorbing structure and a reflective structure, a solar simulated light source was used to irradiate the device with intense sunlight, and the output voltage was 70.1mV. This demonstrates that the design structure can achieve multiple temperature differences and improve the thermoelectric output performance.

[0110] The above test results show that the present invention realizes the rapid fabrication of thermoelectric devices through 3D printing. Furthermore, the heat insulation structure and the heat conduction structure establish a temperature difference by isolating the temperature to the cold end of the thermoelectric device and conducting the temperature to the hot end of the thermoelectric device, thereby improving the output performance of the thermoelectric device. Conversely, the heat absorption structure and the reflection structure establish a temperature difference by absorbing sunlight to the hot end of the thermoelectric device and reflecting sunlight to the cold end of the thermoelectric generator, thereby improving the output performance of the thermoelectric device.

[0111] The thermoelectric device prepared by this invention can be used to improve the output performance of wearable thermoelectric generators. It is manufactured using 3D printing technology, which simplifies the operation process and reduces raw material waste. Furthermore, the unique structure of the thermoelectric device is designed so that a temperature difference on the skin side can be established through a heat-conducting structure and a heat-insulating structure, and a temperature difference between the skin side and the environment side can be increased through a heat-absorbing structure and a reflective structure, thereby improving the output performance of the thermoelectric generator. It can be used to power wearable sensing devices, realize a self-powered wearable sensing system, and reduce its dependence on batteries.

[0112] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for fabricating a thermoelectric device, characterized in that, The steps include: Step S1: Configure the raw materials for thermoelectric structure printing, which include support material, N-type 3D printing thermoelectric ink, and P-type 3D printing thermoelectric ink; Step S2: Using the configured thermoelectric structure printing raw materials, the thermoelectric structure is printed using 3D printing ink direct writing technology; the thermoelectric structure includes a support structure, an N-type planar thermoelectric structure, a P-type thermoelectric planar structure, a three-dimensional N-type thermoelectric leg, a three-dimensional P-type thermoelectric leg, and an electrode connection part; Step S3: Perform heat treatment on the 3D-printed thermoelectric structure; Step S4: Configure the thermally conductive material and use the configured thermally conductive material to print the thermally conductive structure using 3D printing ink direct writing technology; Step S5: Configure the thermal insulation material and use the configured thermal insulation material to print the thermal insulation structure using 3D printing ink direct writing technology; Step S6: Configure the heat-absorbing material and use the configured heat-absorbing material to print the heat-absorbing structure using 3D printing ink direct writing technology; Step S7: Configure the reflective material and use the configured reflective material to print the reflective structure using 3D printing ink direct writing technology; Step S8: Assemble the 3D-printed thermoelectric structure, thermally conductive structure, thermally insulating structure, thermally absorbing structure, and reflective material into a thermoelectric device.

2. The method for preparing the thermoelectric device according to claim 1, characterized in that, Step S1 includes the following steps: Step S11: Prepare the support material: Mix polydimethylsiloxane (PDMS1700) and crosslinking agent at a mass ratio of 10:1 to obtain the support material; and transfer it to the barrel required for 3D printing. Step S12: Preparation of epoxy resin base liquid: 2-Ethyl-4-methyl-1H-imidazolium-1-propionitrile (EMIP) is used as a catalyst, accounting for 1% by mass; polypropylene glycol diglycidyl ether (PPGDGE) and bisphenol F diglycidyl ether (BPFDGE) are uniformly mixed in a 1:1 mass ratio to form liquid epoxy resin, accounting for 60.4% by mass; methyl hexahydrophthalic anhydride (MHHPA) is used as a curing agent, accounting for 38.6% by mass; the catalyst, liquid epoxy resin and curing agent are uniformly mixed to obtain epoxy resin base liquid; Step S13: Prepare N-type 3D printing thermoelectric ink: using bismuth telluride (Bi2Te) 2.7 Se 0.3 As N-type thermoelectric powder, the mass ratio of N-type thermoelectric powder to epoxy resin base liquid is 5:1, and volatile diluent n-butyl acetate is added for dilution; the mixture is then used in a ball mill at a speed of 400 r / min for 4 h to ensure uniform mixing of the thermoelectric ink, thus obtaining N-type 3D printing thermoelectric ink; the N-type thermoelectric ink is then transferred to the barrel required for 3D printing and degassed using a vacuum stirring degassing machine. Step S14: Prepare P-type 3D printing thermoelectric ink: Use antimony telluride Sb2Te3 as P-type thermoelectric powder, and make the mass ratio of P-type thermoelectric powder to epoxy resin base liquid 6:

1. Add volatile diluent n-butyl acetate for dilution; use a ball mill at a speed of 400 r / min for 4 h to mix the thermoelectric ink evenly and obtain P-type 3D printing thermoelectric ink; transfer the P-type thermoelectric ink to the barrel to be used for 3D printing, and use a vacuum stirring degassing machine for degassing treatment.

3. The method for preparing a thermoelectric device according to claim 1, characterized in that, Step S2 includes the following steps: Step S21: Print a support structure on the glass substrate using a support material; the support structure is 35mm long, 1.5mm wide, and 1.3mm high; the support structure is printed evenly on the glass substrate with a 6mm gap between each other along its long side; Step S22: Print an N-type planar thermoelectric structure using N-type 3D printing thermoelectric ink; the N-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high; the N-type planar thermoelectric structure is printed in the gap of the support structure, and the long side of the N-type planar thermoelectric structure is perpendicular to the long side of the support structure. Along the long side of the vertical support structure, N-type planar thermoelectric structures and P-type thermoelectric planar structures are printed alternately in the gaps between the support structures. Along the long side of the parallel support structure, N-type planar thermoelectric structures and P-type thermoelectric planar structures are printed alternately in the gap between the support structures, with a gap of one support structure width between the N-type planar thermoelectric structures and the P-type thermoelectric planar structures, i.e., a gap of 1.5mm. Step S23: Print a P-type planar thermoelectric structure using P-type 3D printing thermoelectric ink; the P-type planar thermoelectric structure is 6mm long, 2mm wide, and 0.3mm high; the P-type planar thermoelectric structure is printed in the gap of the support structure, and the long side of the P-type planar thermoelectric structure is perpendicular to the long side of the support structure. Along the long side of the vertical support structure, P-type planar thermoelectric structures and N-type thermoelectric planar structures are printed alternately in the gaps between the support structures; along the long side of the parallel support structure, N-type planar thermoelectric structures and P-type thermoelectric planar structures are printed alternately in the gaps between the support structures. Step S24: Print N-type thermoelectric legs using N-type 3D printing thermoelectric ink; the length of the N-type thermoelectric leg is 2mm, the width is 2mm, and the height is 1mm; the N-type thermoelectric leg is printed on the N-type planar thermoelectric structure or the P-type planar thermoelectric structure above the planar structure, close to the support structure, the N-type thermoelectric leg and the P-type thermoelectric leg are printed alternately on both sides of the support structure, the P-type thermoelectric leg (22) and the N-type thermoelectric leg (23) in the gap of the support structure form a Π-shaped structure with the P-type planar thermoelectric structure (21) or the N-type planar thermoelectric structure (24) below; Step S25: Print P-type thermoelectric legs using P-type 3D printing thermoelectric ink; N-type thermoelectric legs are 2mm long, 2mm wide, and 1mm high; P-type thermoelectric legs are printed on top of the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the support structure, and P-type thermoelectric legs and N-type thermoelectric legs are printed alternately on both sides of the support structure. Step S26: Print the electrode connection part using N-type 3D printed thermoelectric ink. The electrode connection part is 5.5mm long, 2mm wide, and 0.3mm high. The electrode connection part includes a top electrode and a bottom electrode. Print the top electrode above the support structure so that the top electrode spans the support structure and connects the N-type thermoelectric legs and P-type thermoelectric legs on both sides of the support structure, so that it forms a Π-type structure with the N-type thermoelectric legs and P-type thermoelectric legs. Print the bottom electrode on the substrate so that the bottom electrode connects the N-type planar thermoelectric structures and P-type planar thermoelectric structures on each row of edges to form a series connection.

4. The method for preparing a thermoelectric device according to claim 1, characterized in that, Step S4 includes the following steps: Step S41: The thermal conductive material is composed of polydimethylsiloxane (PDMS184) and boron nitride; the polydimethylsiloxane (PDMS184) is mixed at a mass ratio of 70% and the boron nitride is mixed at a mass ratio of 30% and stirred evenly to obtain the thermal conductive material, and the thermal conductive material is transferred to the material cylinder required for 3D printing; Step S42: Using the prepared thermally conductive material and 3D printing ink direct writing technology, print multiple cuboid thermally conductive structures with a length of 35mm, a width of 6mm, and a height of 2mm; perform heat treatment at 70 degrees Celsius for 1 hour on the 3D printed cuboid thermally conductive structures.

5. The method for preparing a thermoelectric device according to claim 1, characterized in that, Step S5 includes the following steps: Step S51: The thermal insulation material is composed of silica aerogel and PVA aqueous solution; the silica aerogel has a particle size of 800 mesh and a mass ratio of 10%, and the PVA aqueous solution has a mass ratio of 90%, wherein the PVA aqueous solution is made by dissolving 12.5% ​​PVA in water at 90 degrees Celsius; the silica aerogel and PVA aqueous solution are mixed and stirred evenly to prepare the thermal insulation material, and the thermal insulation material is transferred to the material cylinder required for 3D printing; Step S52: Using the prepared thermal insulation material and 3D printing ink direct writing technology, print multiple cuboid thermal insulation structures with a length of 35mm, a width of 6mm, and a height of 2mm; perform heat treatment at 70 degrees Celsius for 1 hour on the 3D printed cuboid thermal insulation structures.

6. The method for preparing a thermoelectric device according to claim 1, characterized in that, Step S6 includes the following steps: Step S61: The heat-absorbing material is composed of carbon black and polydimethylsiloxane (PDMS184). The polydimethylsiloxane (PDMS184) is mixed with carbon black at a mass ratio of 91.5% and stirred evenly to obtain the heat-absorbing material. The heat-absorbing material is then transferred to the material cylinder required for 3D printing. Step S62: Using the prepared heat-absorbing material and 3D printing ink direct writing technology, print multiple cuboid heat-absorbing structures with a length of 35mm, a width of 6mm, and a height of 0.3mm; heat-treat the 3D-printed cuboid heat-absorbing structures at 70 degrees Celsius for 1 hour.

7. The method for preparing a thermoelectric device according to claim 1, characterized in that, Step S7 includes the following steps: Step S71: The reflective material is composed of silica aerogel and PVA aqueous solution; wherein the silica aerogel has a particle size of 800 mesh and a mass ratio of 10%, and the PVA aqueous solution has a mass ratio of 90%, wherein the PVA aqueous solution is made by dissolving 12.5% ​​PVA in water at 90 degrees Celsius; the silica aerogel and PVA aqueous solution are mixed and stirred evenly to prepare the reflective material, and the reflective material is transferred to the material cylinder required for 3D printing; Step S72: Using the prepared reflective material and 3D printing ink direct writing technology, print multiple cuboid reflective structures with a length of 35mm, a width of 6mm, and a height of 0.3mm; perform heat treatment at 70 degrees Celsius for 1 hour on the 3D printed cuboid reflective structures.

8. The method for preparing a thermoelectric device according to claim 1, characterized in that, Step S8 includes the following steps: Place the 3D-printed thermally conductive and thermally insulating structures side by side alternately, and place the thermoelectric structure above the thermally conductive and thermally insulating structures; so that the thermally conductive and thermally insulating structures are both located directly below the supporting structure; A heat-absorbing structure and a reflective structure are placed above the thermoelectric structure; the heat-absorbing structure and the reflective structure are placed side by side and alternately, so that the heat-absorbing structure is connected to the top electrode of the thermoelectric structure, and the reflective structure is located at the interval of the top electrode, thus forming a thermoelectric device.

9. A thermoelectric device, characterized in that, The thermoelectric device is prepared by the method of any one of claims 1 to 8, and the thermoelectric device includes a reflective and heat-absorbing layer (1), a thermoelectric structure (2), and a heat-conducting and heat-insulating layer (3).

10. The thermoelectric device according to claim 9, characterized in that, The thermally conductive and insulating layer (3) is composed of a thermally conductive structure (32) and a thermally insulating structure (31); multiple thermally conductive structures (32) and multiple thermally insulating structures (31) are placed side by side alternately along the long side; The thermoelectric structure (2) consists of a P-type planar thermoelectric structure (21), a P-type thermoelectric leg (22), an N-type thermoelectric leg (23), an N-type planar thermoelectric structure (24), a support structure (25), a bottom electrode (26), and a top electrode (27). Multiple support structures are placed side-by-side at intervals along their long sides. The support structure (25) is 35mm long, 1.5mm wide, and 1.3mm high, with a gap of 6mm. The P-type planar thermoelectric structure (21) is 6mm long, 2mm wide, and 0.3mm high. The N-type planar thermoelectric structure (24) is 6mm long, 2mm wide, and 0.3mm high. 0.3mm; the length of the P-type thermoelectric leg (22) is 2mm, the width is 2mm, and the height is 1mm; the length of the N-type thermoelectric leg (23) is 2mm, the width is 2mm, and the height is 1mm; the P-type planar thermoelectric structure (21) and the N-type planar thermoelectric structure (24) are alternately arranged in the gap of the support structure (25), and the width of the long side of the P-type planar thermoelectric structure (21) and the N-type planar thermoelectric structure (24) is exactly equal to the gap width of the support structure; the long side of the P-type planar thermoelectric structure (21) and the N-type planar thermoelectric structure (24) is perpendicular to the long side of the support structure (25), and they are arranged in several rows; The P-type thermoelectric leg (22) and the N-type thermoelectric leg (23) are located above the N-type planar thermoelectric structure or the P-type planar thermoelectric structure, close to the support structure. The N-type thermoelectric leg and the P-type thermoelectric leg are alternately arranged on both sides of the support structure. The P-type thermoelectric leg (22) and the N-type thermoelectric leg (23) in the gap of the support structure form a Π-type structure with the P-type planar thermoelectric structure (21) or the N-type planar thermoelectric structure (24) below. The bottom electrode (26) connects the edge N-type planar structure and P-type planar structure of each row to form a series connection; the top electrode (27) spans the support structure and connects the P-type thermoelectric leg (22) and N-type thermoelectric leg (23) on both sides of the support structure, so that it forms a Π-type structure with the N-type thermoelectric leg and the P-type thermoelectric leg. The thermoelectric structure (2) is placed above the heat-conducting and heat-insulating layer (3), so that both the heat-conducting structure and the heat-insulating structure are located directly below the supporting structure; A reflective and heat-absorbing layer (1) is placed above the thermoelectric structure (2); the reflective and heat-absorbing layer (1) is composed of a heat-absorbing structure (11) and a reflective structure (12), and multiple heat-absorbing structures (11) and multiple reflective structures (12) are placed side by side alternately; the heat-absorbing structure (11) is connected to the top electrode (27) of the thermoelectric structure, and the reflective structure (12) is located at the interval between the two top electrodes.

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