Flexible thermoelectric device containing superstructure electrode and preparation method thereof

Abstract

The invention relates to the technical field of thermoelectric conversion, in particular to a flexible thermoelectric device containing a super-structure electrode and a preparation method of the flexible thermoelectric device. The flexible thermoelectric device is prepared from a flexible substrate silica gel plate which can be stretched and bent, silicon resin, the super-structure electrode and a thermoelectric material. The flexible substrate and the superstructure electrode are combined to form an electrode substrate with zero Poisson's ratio, so that the flexible thermoelectric device has high reliability and good compactness under the condition of stretching and bending deformation, and the flexible thermoelectric device has the stretching rate of about 20% under the condition of not influencing the power generation power; after 3000 times of cyclic bending deformation, the output power keeps 98% or above of the original output power, and the maximum power density is 109.2 W / m < 2 > under the temperature difference of 200K for a long time. The preparation method of the flexible thermoelectric device containing the superstructure electrode is simple in process, efficient, energy-saving and low in cost, and the device is wide in application range, high in production efficiency, low in defective rate and capable of being produced on a large scale.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoelectric conversion, and in particular to a flexible thermoelectric device containing a superstructure electrode and a preparation method thereof. Background Art

[0002] Vigorously developing clean energy and improving energy efficiency are important ways to achieve the goals of carbon peak and carbon neutrality. The rapid development of wearable electronic products has prompted people to seek more durable and stable flexible wearable power solutions. Thermoelectric technology can directly convert thermal energy such as solar thermal energy, industrial waste heat, and biological heat into electrical energy, and is an ideal choice for realizing clean energy technology and self-powered electronic products. In order to fit curved surfaces such as industrial pipelines and biological surfaces, flexible thermoelectric devices came into being. In addition, since heat sources such as industrial pipelines and biological surfaces are curved surfaces, and the surface of the organism is constantly changing with the movement, flexible thermoelectric devices with simple bendability are difficult to fit tightly to the surface of the skin when it is extended, which can easily cause it to fall off or be damaged. However, existing flexible thermoelectric devices still face problems such as low power density, low reliability, and difficulty in processing. Therefore, the development of efficient and stable flexible thermoelectric devices and their mass preparation methods is of great significance to the development of energy conservation and carbon reduction and flexible electronics.

[0003] In terms of power density, the Chinese invention patent with publication number CN115274995A discloses a method for preparing an in-plane flexible wearable thermoelectric device using a PVP nanofiber film. In its performance test embodiment, at a temperature difference of 60K, the electromotive force generated by the device is only 1.5mV, which is due to the difficulty in establishing a large temperature difference in the in-plane structure. In the Chinese invention patent with publication number CN11611330A, when the temperature difference between the two ends of the stretchable flexible thermoelectric device prepared by the Ag2S / PEDOT / Mxene flexible thermoelectric film reaches 260K, the output voltage is only 11.2mV. According to the paper corresponding to the Chinese invention patent with publication number CN107046092A (DOI10.1109 / LRA.2017.2734241), its maximum power density is 4.75×10 -2 W / m 2 .

[0004] In terms of reliability, for example, the electrodes and traditional electrode sheets used in the Chinese invention patent with publication number CN107046092A cannot provide stretching and bending functions, and the processing is complicated, which is not conducive to mass production, which has great limitations on the development and application of flexible stretchable thermoelectric devices. In addition, the metal electrode in the Chinese invention patent (CN116471914A) is 100um thick metal copper. This thin electrode is prone to cracks or fractures due to mechanical fatigue, bending or thermal expansion mismatch, affecting long-term stability. The Chinese invention patent (CN115274995A) uses silver paste as the electrode material, which may cause poor contact or detachment between the electrode and the thermoelectric arm under long-term exposure to the environment or mechanical deformation, affecting the stable operation of the device and posing reliability problems.

[0005] In terms of processing difficulty, the existing technology requires secondary positioning of the cold-end copper conductive sheet through 3D printing, which not only increases the complexity of processing, but also easily introduces errors, resulting in low production efficiency and affecting product consistency and quality. In addition, when the thickness of the electrode sheet in the Chinese invention patent (CN116471914A) is 0.1mm, the processing technology requirements are extremely high. In flexible stretchable devices, the electrode material usually needs to be bonded to the flexible substrate, and an electrode sheet that is too thin may be easily deformed or broken during processing.

[0006] Flexible stretchable thermoelectric devices have important application potential in wearable devices and waste heat recovery of industrial pipelines, but technical problems such as low power density and stability still need to be solved. Therefore, there is an urgent need for a stretchable flexible thermoelectric device and its manufacturing method that can be efficiently and cost-effectively mass-produced, and can solve the problems of low power density, low reliability, and high processing difficulty of current stretchable flexible thermoelectric devices, improve the device output power density and reliability, simplify the difficulty of processing and production processes, and realize mass production. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a flexible thermoelectric device containing a superstructure electrode and a preparation method thereof, which solves the technical problems of low power density, low reliability and great processing difficulty still faced by the existing flexible thermoelectric devices.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a flexible thermoelectric device containing superstructure electrodes, comprising a hot-end flexible substrate and a cold-end flexible substrate distributed in parallel up and down or left and right, a plurality of superstructure electrodes distributed in an array are arranged between the hot-end flexible substrate and the cold-end flexible substrate, the superstructure electrode comprises a hot-end stretchable electrode array and a cold-end stretchable electrode array, and are respectively fixed on a surface opposite to the hot-end flexible substrate and the cold-end flexible substrate, grooves matching the hot-end stretchable electrode array and the cold-end stretchable electrode array are arranged on the hot-end flexible substrate and the cold-end flexible substrate, a thermoelectric block array connected to the hot-end stretchable electrode array and the cold-end stretchable electrode array is arranged between the hot-end stretchable electrode array and the cold-end stretchable electrode array, and the thermoelectric block array forms an electrical series structure with the cold-end stretchable electrode array through the hot-end stretchable electrode array.

[0009] Furthermore, the superstructure electrode comprises an N-terminal electrode sheet and a P-terminal electrode sheet which are bonded and fixed in the groove, a connecting portion is provided between the N-terminal electrode sheet and the P-terminal electrode sheet, and the whole presents a symmetrical and stretchable superstructure.

[0010] Furthermore, the connecting portion includes line segment bodies respectively connected to the two sides of the opposite vertical surfaces of the N-terminal electrode sheet and the P-terminal electrode sheet, and a connecting arc forming an integrated structure is arranged between the two line segment bodies, and the connecting portion is composed of a semicircular connecting arc and two 1 / 4 circular connecting arcs.

[0011] Furthermore, the thermoelectric block array includes a plurality of thermoelectric block pairs arranged in an array, each thermoelectric block pair consists of an N-type thermoelectric block and a P-type thermoelectric block, and one end of the bottom surface of the two ends of the P-type thermoelectric block or the N-type thermoelectric block is a hot end bottom surface, and the other end is a cold end bottom surface.

[0012] Furthermore, the superstructure electrode is combined with a flexible substrate to form a flexible electrode substrate with zero Poisson's ratio, which is used to eliminate the torque generated by the unequal elongation of the hot-end and cold-end electrode substrates during the bending process of the flexible thermoelectric device.

[0013] Furthermore, the middle portion of the superstructure electrode has a strong deformation capability, which is used to suppress the interface force between the thermoelectric block array and the superstructure electrode during the stretching and bending process of the thermoelectric device.

[0014] Furthermore, the N-type thermoelectric block and the P-type thermoelectric block have the same shape and size, and are rectangular parallelepipeds with square bottom surfaces.

[0015] The technical solution also provides a method for manufacturing the above-mentioned flexible thermoelectric device, comprising the following steps: S1, cutting the N-type semiconductor thermoelectric material sheet and the P-type semiconductor thermoelectric material sheet into thermoelectric units of N-type thermoelectric blocks and P-type thermoelectric blocks according to size, and cleaning them for later use; S2, using laser cutting of pure copper sheets to form superstructure electrodes, which are new superstructure electrode sheets with stretchable and bendable properties, high conductivity, stability and easy processing after repeated design attempts; S3, evenly coating the inner surface of the hot-end flexible substrate with thermally conductive silicone to make it uniform and sticky; designing a flexible electrode substrate mold with a groove, the shape of the groove is designed and arranged according to the size of the super-structure electrode, so that the electrode sheet can be embedded in the groove; S4. Before the superstructure electrode is embedded into the groove, liquid carbon powder needs to be evenly sprayed on the surface of the flexible electrode substrate mold, and the electrode sheet is placed in the groove after the carbon powder is completely solidified; S5. Press the hot-end flexible substrate with thermally conductive silicone onto the mold, and then place a cubic pressing object on it to make the electrode sheet and the hot-end flexible substrate with thermally conductive silicone fit perfectly. After at least 3 hours, slowly take out the hot-end flexible substrate with the electrode sheet. S6, manufacturing a cold-end flexible substrate with an electrode sheet in the same manner as steps S2-S5; S7. Place the prepared hot-end flexible substrate and cold-end flexible substrate on a screen printer to prepare for coating with conductive solder paste. The screen printer is equipped with a customized substrate positioning grid and bottom plate, which can ensure that the conductive solder paste is evenly and accurately coated on the electrode sheet. Coat the hot-end flexible substrate and the cold-end flexible substrate with low-temperature solder, and remove them for later use after coating. S8, placing the cold-end flexible substrate flat on the auxiliary mold, then pressing the positioning mold for positioning the thermoelectric block array onto the cold-end flexible substrate so that its positioning holes exactly correspond to the positions of each electrode sheet, then placing the N-type thermoelectric block and the P-type thermoelectric block into the positioning mold in an electrically series and thermally parallel arrangement structure, then placing the pillar mold on the positioning grid surface and applying slight pressure to it so that the thermoelectric block array and the conductive solder paste fit tightly, then slowly lifting the positioning mold with the help of the pillar mold to obtain a cold-end flexible substrate with neatly arranged thermoelectric particles; S9, fix the hot-end flexible substrate in position using a positioning mold and cover the neatly arranged thermoelectric particles, so that the thermoelectric block array and the electrode sheet of the hot-end flexible substrate are accurately positioned and closely fitted; S10, placing it on the mold for fixing the thermoelectric device, placing a pressing block, and then applying pressure downward with a bolt spring to make it compact; S11, placing the thermoelectric device and the fixed mold together on a constant temperature heating table for heating and curing; S12. Finally, the electrode sheets are connected with wires, and the tin wire is melted with a high-temperature gun to make liquid droplets on the wires and copper electrodes, so that they are solidified and connected, thereby obtaining a stretchable flexible thermoelectric device.

[0016] By means of the above technical solution, the present invention provides a flexible thermoelectric device containing a superstructure electrode and a preparation method thereof, which has at least the following beneficial effects: 1. The flexible thermoelectric device proposed in the present invention has a simple preparation process, high efficiency and energy saving, low cost, a wide range of applications, high production efficiency and low defective rate, can be mass-produced, and has better stretchability and power generation performance, and also has good bendability.

[0017] 2. The superstructure electrode proposed in the present invention can not only ensure high conductivity, but also maintain excellent flexibility when stretched and bent. The electrode significantly improves the stretchability and bendability of the device, and can achieve a larger elongation ratio when stretched, surpassing the performance of current common electrodes, providing better user experience and reliability, and is easy to mass-produce in industrial production, facilitating commercial application.

[0018] 3. The present invention adopts a silicone plate to replace the traditional polyimide as a flexible substrate, and uses silicone resin glue to replace epoxy resin. The superstructure electrode and the flexible substrate are compounded into a flexible electrode substrate with zero Poisson's ratio, which is used to eliminate the torque generated by the unequal elongation of the hot-end and cold-end electrode substrates during the bending process of the flexible thermoelectric device.

[0019] 4. In order to further improve the performance of flexible thermoelectric devices, the present invention retains the connection mode of electrical series and thermal parallel connection of commercial thermoelectric devices to the greatest extent, which is not only suitable for various high-performance thermoelectric materials, but also conducive to establishing temperature difference and improving output power. At the same time, the structure similar to commercial thermoelectric devices is more conducive to mass production. Therefore, the flexible thermoelectric device has a high power density, high stability, simple structure, simple manufacturing process, low manufacturing cost, can be mass produced, and has good commercial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 is a schematic structural diagram of the flexible thermoelectric device in the present invention; Figure 2 is a schematic diagram of the structure of the superstructure electrode in the present invention; Figure 3 A flow chart for making a flexible thermoelectric device in the present invention; Figure 4 Schematic diagram of the array distribution of superstructure electrodes on the cold-end flexible substrate in the present invention; Figure 5 Schematic diagram of the array distribution of superstructure electrodes on the hot-end flexible substrate in the present invention; Figure 6This is a schematic diagram of a flexible electrode substrate mold having a groove at the cold end of the present invention; Figure 7 It is a schematic diagram of a flexible electrode substrate mold having a groove at the hot end of the present invention; Figure 8 This is a graph showing how the output power of the flexible thermoelectric device tested in the present invention changes with the increase in the number of bends.

[0021] In the figure: 1, hot end flexible substrate; 2, cold end flexible substrate; 3, superstructure electrode; 31, N-end electrode sheet; 32, P-end electrode sheet; 33, connecting part; 331, 1 / 4 circular connecting arc; 332, semicircular connecting arc; 4. Thermoelectric block array; 41. N-type thermoelectric block; 42. P-type thermoelectric block; 5. A flexible electrode substrate mold having a groove at the cold end; 51. The groove; 6. A flexible electrode substrate mold with a groove at the hot end. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. Embodiment 1

[0023] Please refer to Figure 1-Figure 2 This embodiment proposes a flexible thermoelectric device with a superstructure electrode, which uses a silicone plate instead of traditional polyimide as a flexible substrate, and uses silicone resin glue instead of epoxy resin. The high conductivity of the superstructure electrode not only enhances the performance of the device, but also ensures good adaptation between materials. At the same time, a large temperature difference of 200K is established to produce a maximum power density of 109.2W / m 2 It has the advantages of simple preparation process, high efficiency and energy saving, low cost, wide application range, high production efficiency and low defective rate, mass production, better stretchability and power generation performance, and good bendability.

[0024] like Figure 1As shown, the hot-end flexible substrate 1 and the cold-end flexible substrate 2 are arranged in a parallel state of stacking up and down. The hot-end flexible substrate 1 and the cold-end flexible substrate 2 are both silicone plates. The silicone has strong high-temperature stability, good flexibility and elasticity, and has low thermal conductivity, which can effectively isolate the heat source and improve the thermoelectric efficiency. A plurality of super-structure electrodes 3 distributed in an array are arranged between the hot-end flexible substrate 1 and the cold-end flexible substrate 2. The super-structure electrode 3 includes a hot-end stretchable electrode array and a cold-end stretchable electrode array, and is respectively fixed on the opposite surfaces of the hot-end flexible substrate 1 and the cold-end flexible substrate 2. Thermal conductive silicone is evenly coated on the inner surface of the hot and cold-end flexible substrates to make them uniform and sticky; then, a groove of a flexible electrode substrate mold containing a groove at the hot and cold ends of the electrode sheet is designed, and the shape of the groove is designed and arranged according to the size of the super-structure electrode. The length and width of the groove are 7.62mm×2.82mm, and the electrode sheet can be embedded in the groove. Each groove has a concave distance of 0.1mm, and the thickness of the groove is 0.5mm. A thermoelectric block array 4 connected to the hot-end stretchable electrode array and the cold-end stretchable electrode array is provided between the hot-end stretchable electrode array and the cold-end stretchable electrode array. The thermoelectric block array 4 forms an electrical series structure with the cold-end stretchable electrode array through the hot-end stretchable electrode array.

[0025] Specifically, the adhesive between the hot-end stretchable electrode array and the cold-end stretchable electrode array and the thermoelectric block array 4 is silicone resin. Silicone resin has stronger metal adhesion, elasticity and stretchability, can adapt to dynamic environmental changes, avoid damage caused by the external environment, and has excellent high temperature and chemical corrosion resistance, and can adapt to long-term work under harsh conditions.

[0026] This embodiment preferably uses 31 thermoelectric block pairs, which are made of two types of P\N type thermoelectric materials cut into thermoelectric legs with appropriate length, width and height. Each thermoelectric block pair consists of an N type thermoelectric block 41 and a P type thermoelectric block 42. The N type thermoelectric block 41 and the P type thermoelectric block 42 have the same shape and size, with a bottom surface of a square with a side length of 2.5 mm and a height of 3 mm. The bottom surfaces of the two ends of the P type thermoelectric block 42 or the N type thermoelectric block 41 are one hot end bottom surface and the other end is a cold end bottom surface. The material composition of the P type thermoelectric block 42 is Bi 0.5 Sb 1.5 Te3, the material composition of the N-type thermoelectric block 41 is Bi2Te 2.7 Se 0.3 .

[0027] like Figure 2As shown, the superstructure electrode 3 is a superstructure electrode made of pure copper sheets by high-precision laser cutting. The superstructure electrode 3 is a new superstructure electrode sheet with stretchable characteristics after repeated design attempts. It has high conductivity, stretchability, stability and easy processing characteristics. The superstructure electrode greatly improves the stretching length and can establish a large temperature difference, thereby increasing the power density. A connecting portion 33 is provided between the N-terminal electrode sheet 31 and the P-terminal electrode sheet 32, and the whole presents a symmetrical stretchable superstructure. The length, width and thickness of the superstructure electrode 3 are 7.6mm×2.8mm×0.2mm, and the width of the middle portion 33 is 0.2mm. The connection part 33 includes 1 / 4 circular connection arcs 331 connected to the two sides of the opposite vertical surfaces of the N-terminal electrode sheet 31 and the P-terminal electrode sheet 32, and a semicircular connection arc 332 in an integrated structure is arranged between the 1 / 4 circular connection arcs 331 at both ends. The connection part 33 is composed of a 1 / 4 circular connection arc 331 with a radius of 0.4 mm and a semicircular connection arc 332 with a radius of 0.6 mm. The whole presents a symmetrical and stretchable superstructure, and the stretchable characteristics brought by this superstructure array can be clearly seen.

[0028] The flexible thermoelectric device proposed in the present invention is made of a flexible substrate silicone plate that can be stretched and bent, silicone resin, superstructure electrode and commercial bismuth telluride thermoelectric material. The flexible substrate and the superstructure electrode are combined to form an electrode substrate with zero Poisson's ratio, so that the flexible thermoelectric device can be stretched under tensile stress and bending deformation and has high reliability and good compactness. Without affecting the power generation, the flexible thermoelectric device has a stretching rate of about 20%, and the maximum power density is 109.2W / m2 under a temperature difference of 200K for a long time. Embodiment 2

[0029] Please refer to Figure 3-Figure 8 This embodiment proposes a method for preparing a flexible thermoelectric device containing a superstructure electrode. The method has simple process, high efficiency and energy saving, low cost, wide application range, high production efficiency and low defect rate, can be mass-produced, and has better stretchability and power generation performance. In addition, it has good bendability. The output power after 3000 cycles of bending deformation remains more than 98% of the original output power. It can be seen that the output power of the flexible thermoelectric device has good stability. The method comprises the following steps: S1. Cut the N-type semiconductor thermoelectric material sheet and the P-type semiconductor thermoelectric material sheet into thermoelectric units of N-type thermoelectric blocks and P-type thermoelectric blocks according to size, and clean them for later use.

[0030] S2. Use laser-cut pure copper sheets to form superstructure electrodes. This superstructure electrode is a new type of superstructure electrode sheet that has been repeatedly designed and tried, and has stretchable and bendable properties, high conductivity, stability and easy processing.

[0031] S3, evenly apply thermal conductive silicone on the inner surface of the hot-end flexible substrate to make it uniform and sticky; design a hot-end flexible electrode substrate mold with a groove that can be embedded with an electrode sheet, and the shape of the groove 51 is designed according to the size of the super-structure electrode, so that the electrode sheet can be embedded in the groove 51. At the same time, the electrode sheet can be arranged according to the array distribution of the super-structure electrode on the hot-end flexible substrate, so that it can be perfectly attached to the hot-end flexible substrate.

[0032] S4. Before the superstructure electrode is embedded into the groove 51, it is necessary to spray liquid carbon powder evenly on the surface of the groove 51, and put the electrode sheet in after the carbon powder is completely solidified. Specifically, spray carbon powder on the surface of the groove three times and let it stand for 2 hours to ensure that the carbon powder is completely dry to avoid contamination by the silicone resin glue and the undried carbon powder, which will affect the adhesion between the superstructure electrode and the silicone resin. After the carbon powder is completely dry, use tweezers to clip the electrode sheets into the grooves respectively. In order to facilitate the placement of the superstructure electrode with a length and width of 7.6mm×2.8mm, the length and width of the groove are designed to be 7.62mm×2.82mm, and each small groove has a concave distance of 0.1mm to facilitate the fixing of the position of the electrode sheet.

[0033] S5. Press the hot-end flexible substrate with thermally conductive silicone onto the mold, and then place a cubic pressing object on it to make the electrode sheet and the hot-end flexible substrate with thermally conductive silicone fit perfectly. After at least 3 hours, slowly take out the hot-end flexible substrate with the electrode sheet; after putting all the electrode sheets into the hot-end flexible electrode substrate mold with grooves and uniform carbon powder, use silicone resin glue, cold and hot-end flexible substrates, and weight blocks to prepare a flexible substrate with silicone resin glue. First, cut the flexible substrate of 40mm×40mm, and then lay it flat on the weight block of 40mm×40mm×8mm in length, width and height. Since there is a suction force when the weight block and the flexible substrate are pressed tightly, the two can fit closely for a period of time. Then, squeeze the silicone resin glue evenly on the cold and hot end flexible substrates, and after applying it evenly, two cold and hot end flexible substrates with silicone resin are obtained. Then, the side of the cold and hot end flexible substrates with silicone resin is completely fitted with the electrode substrate mold with the superstructure electrode placed, and finally wait for eight hours to take out the hot end flexible substrate 1 with superstructure and the cold end flexible substrate 2 with superstructure. The surface of the cold and hot end flexible substrates taken out is very smooth and clean, with almost no carbon powder pollution, and the combination of the superstructure electrode and silicone resin and the cold and hot end flexible substrates is also very good.

[0034] S6, manufacturing a cold-end flexible substrate with an electrode sheet in the same manner as steps S2-S5; S7, put the prepared hot-end flexible substrate 1 with super-structure electrode and the cold-end flexible substrate 2 with super-structure electrode on the screen printer to prepare for coating with conductive solder paste, and the customized substrate positioning grid and bottom plate on the screen printer can make the conductive solder paste evenly and accurately coated on the electrode sheet. Apply low-temperature solder to both the hot-end flexible substrate and the cold-end flexible substrate, and remove them for use after coating.

[0035] Place the removed hot-end flexible substrate 1 with superstructure electrodes and the removed cold-end flexible substrate 2 with superstructure electrodes in the groove for fixing the hot-end flexible substrate and the groove for fixing the cold-end flexible substrate respectively. The thickness of the groove is 0.5 mm, the same as the thickness of the flexible substrate. The purpose of this is to use the grid to completely fit the electrode sheet, so that it is convenient to brush the conductive solder paste at one time. Then, position the four circular positioning holes of the base on the instrument for brushing the conductive solder paste, adjust the distance so that each electrode sheet and the grid fit correspondingly, and then brush the low-temperature solder evenly. Then, use the rectangular holes to take out the hot-end flexible substrate 1 with superstructure electrodes and the cold-end flexible substrate 2 with superstructure electrodes for use.

[0036] S8. Place the cold-end flexible substrate 2 with superstructure electrodes flatly on the auxiliary mold, and then press the positioning mold for positioning the thermoelectric block array onto the cold-end flexible substrate 2 with superstructure electrodes so that its positioning holes exactly correspond to the positions of each electrode sheet. Then place the N-type thermoelectric block and the P-type thermoelectric block into the positioning mold according to the electrical series and thermal parallel arrangement structure. Then place the pillar mold on the positioning grid surface and apply slight pressure to it so that the thermoelectric block array and the conductive solder paste fit tightly. Then, slowly lift the positioning mold with the help of the pillar mold to obtain a cold-end flexible substrate with neatly arranged thermoelectric particles.

[0037] S9, fix the hot-end flexible substrate 1 with the superstructure electrode in position using a positioning mold and cover it on the neatly arranged thermoelectric particles, so that the thermoelectric block array and the electrode sheet of the hot-end flexible substrate are accurately positioned and closely fitted; S10, placing it on the mold for fixing the thermoelectric device, placing a pressing block, and then applying pressure downward with a bolt spring to make it compact; Specifically, the cold-end flexible substrate 2 with the superstructure electrode is then laid flat on the small base, with the electrode sheet facing upward and the three horizontally arranged electrode sheets facing left. Then, the positioning grid mold is covered directly above the cold-end flexible substrate 2 with the superstructure electrode. The P and N thermoelectric particles that have been cut and cleaned are taken out. First, the N-type thermoelectric particles are filled into the grid holes adjacent to the right of the grid mold holes. Then, the N-type is filled in accordance with the S-shaped surrounding interval. Similarly, the P-type thermoelectric particles are filled. The first P-type is on the right side of the N-type. The grid holes and symmetrical grid holes are not filled with thermoelectric particles. The two extra square copper electrodes are used for soldering and connecting wires. After the P and N-type thermoelectric particles are filled, the pillar mold and the positioning grid mold are overlapped to achieve the effect of slightly compacting the thermoelectric particles. Then, the positioning grid mold can be lifted and removed with the help of the pillar. This design has no effect on the arrangement of the thermoelectric particles and is very convenient. Finally, the hot-end flexible substrate 1 with the superstructure electrode is covered on the surface of the thermoelectric particles.

[0038] The unheated and cured superstructure flexible thermoelectric device is slowly placed on the large base, the small base and the large base are fitted together, and then the weight block is pressed on the hot end flexible substrate 1 with the superstructure electrode, and then the superstructure stretchable flexible thermoelectric device is fixed using a pressurizing device.

[0039] S11, then put the thermoelectric device and the fixed mold together on a constant temperature heating table for heating and curing; finally, raise the temperature of the constant temperature heating table to 260°, place it on the constant temperature heating table for five minutes, and then take it down with pliers and place it on the heat sink to cool down.

[0040] S12. Finally, the electrode sheets are connected with wires, and the tin wire is melted with a high-temperature gun to make liquid droplets on the wires and copper electrodes, so that they are solidified and connected, thereby obtaining a stretchable flexible thermoelectric device.

[0041] like Figure 8 As shown, the prepared flexible thermoelectric device is tested in this embodiment. After the flexible thermoelectric device is cyclically bent and deformed for 3000 times, the output power remains more than 98% of the original output power, which shows that the output power of the flexible thermoelectric device has good stability.

[0042] The flexible thermoelectric device prepared in this embodiment has the characteristics of high conductivity, stretchability, stability and easy processing. The flexible substrate and the superstructure electrode are combined to form an electrode substrate with zero Poisson's ratio, so that the electrode array can be stretched and has good compactness under tensile stress. The flexible thermoelectric device has a stretch rate of about 20% without affecting the power generation. Under a temperature difference of 200K for a long time, the maximum power is 0.174W and the maximum power density is 109.2W / m 2 .

[0043] Compared with the existing technology, the flexible thermoelectric device made by the Chinese invention patent with publication number CN107046092A is not stretchable, and according to its corresponding published paper (DOI10.1109 / LRA.2017.2734241), its maximum power density is 4.75×10 -2 W / m 2 ; The power density of the present invention is about 2300 times that of the present invention. Therefore, the manufacturing method of the present invention and the flexible thermoelectric device obtained have better stretchability and power generation performance.

[0044] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the above embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0045] The above implementation methods have been described in detail. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A flexible thermoelectric device containing a superstructure electrode, comprising a hot-end flexible substrate (1) and a cold-end flexible substrate (2) arranged in parallel vertically or horizontally, characterized in that: A plurality of superstructure electrodes (3) distributed in an array are arranged between the hot-end flexible substrate (1) and the cold-end flexible substrate (2); the superstructure electrodes (3) include a hot-end stretchable electrode array and a cold-end stretchable electrode array, and are respectively fixed on opposite surfaces of the hot-end flexible substrate (1) and the cold-end flexible substrate (2); A thermoelectric block array (4) connected to the hot-end stretchable electrode array and the cold-end stretchable electrode array is provided between the hot-end stretchable electrode array and the cold-end stretchable electrode array, and the thermoelectric block array (4) forms an electrical series structure with the cold-end stretchable electrode array through the hot-end stretchable electrode array.

2. The flexible thermoelectric device according to claim 1, characterized in that: The superstructure electrode (3) comprises an N-terminal electrode sheet (31) and a P-terminal electrode sheet (32) which are bonded and fixed to a hot-end flexible substrate (1) or a cold-end flexible substrate (2); a connecting portion (33) is provided between the N-terminal electrode sheet (31) and the P-terminal electrode sheet (32), and the whole presents a symmetrical and stretchable superstructure.

3. The flexible thermoelectric device according to claim 2, characterized in that: The connecting portion (33) comprises 1 / 4 circular connecting arcs (331) respectively connected to two sides of opposite vertical surfaces of the N-terminal electrode sheet (31) and the P-terminal electrode sheet (32), and a semicircular connecting arc (332) in an integrated structure is arranged between the two 1 / 4 circular connecting arcs (331). The connecting portion (33) consists of a 1 / 4 circular connecting arc 1 (331) and a semicircular connecting arc (332).

4. The flexible thermoelectric device according to claim 1, characterized in that: The thermoelectric block array (4) comprises a plurality of thermoelectric block pairs arranged in an array, each thermoelectric block pair consisting of an N-type thermoelectric block (41) and a P-type thermoelectric block (42), and one end of the bottom surfaces at both ends of the P-type thermoelectric block (42) or the N-type thermoelectric block (41) is a hot end bottom surface, and the other end is a cold end bottom surface.

5. The flexible thermoelectric device according to claim 1, characterized in that: The superstructure electrode (3) is combined with the hot-end flexible substrate (1) or the cold-end flexible substrate (2) to form a flexible electrode substrate with zero Poisson's ratio, which is used to eliminate the torque generated by the unequal elongation of the hot-end and cold-end electrode substrates during the bending process of the flexible thermoelectric device.

6. The flexible thermoelectric device according to claim 1, characterized in that: The middle portion (33) of the superstructure electrode (3) is used to suppress the interface force between the thermoelectric block array (4) and the superstructure electrode (3) during the stretching and bending process of the flexible thermoelectric device.

7. The flexible thermoelectric device according to claim 4, characterized in that: The N-type thermoelectric block (41) and the P-type thermoelectric block (42) have the same shape and size, and are both cuboids with square bottoms.

8. A method for manufacturing the flexible thermoelectric device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, cutting the N-type semiconductor thermoelectric material sheet and the P-type semiconductor thermoelectric material sheet into thermoelectric units of N-type thermoelectric blocks and P-type thermoelectric blocks according to size, and cleaning them for later use; S2, using laser cutting of pure copper sheets to form superstructure electrodes; S3, evenly apply thermal conductive silicone on the inner surface of the hot end flexible substrate to make it uniform and sticky; S4. Design a flexible electrode substrate mold with a groove, spray liquid carbon powder evenly on the surface of the groove of the flexible electrode substrate mold, put the electrode sheet in after the carbon powder is completely solidified, cover the flexible substrate coated with thermal conductive silicone on the electrode sheet and press it, and take out the hot end flexible substrate with the electrode sheet after pressing for at least 3 hours; S5, manufacturing a cold-end flexible substrate with an electrode sheet in the same manner as steps S2-S4; S6, placing the prepared hot-end flexible substrate and cold-end flexible substrate on a screen printer to prepare for coating with conductive solder paste, and removing them for later use after coating; S7, installing the N-type thermoelectric block and the P-type thermoelectric block on the cold-end flexible substrate in an electrically series and thermally parallel arrangement structure, so that the thermoelectric block array and the conductive solder paste are closely attached to obtain a cold-end flexible substrate with neatly arranged thermoelectric particles; S8, cover the hot end flexible substrate on the neatly arranged thermoelectric particles, place a pressure block, and then use a bolt spring to apply pressure downward to make it compact; S9, placing the thermoelectric device and the fixed mold together on a constant temperature heating table for heating and curing; S10. Finally, the electrode sheets are connected with wires, and the tin wire is melted with a high-temperature gun to make liquid droplets on the wires and copper electrodes, so that they are solidified and connected, thereby obtaining a stretchable flexible thermoelectric device.

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